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334 Cards in this Set
- Front
- Back
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What Gram stain are spirochetes?
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-neither gram positive nor negative
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What kind of microscopy is necessary to see spirochetes?
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-darkfield microscopy
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What stain is used to visualize spirochetes?
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-warthrin starry silver nitrate stain
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Are spirochetes motile or nonmotile?
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-motile
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why is it difficult to culture spirochetes?
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-spirochetes are anaerobic or aerobic or micoraerophile
-some have to be grown in culture -cultivated in arthropod vectors, vertebrate hosts, embryonated chicken eggs -cultivation is done in the presence of gelatin and rabbit serum -borrelia can be cultured in barbou-stoenner-kelly II (BSK-II) medium |
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How is the spirochete borellia cultured?
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-with BSK-II medium, pH=7, microaerophilic at 30-37 degrees C
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what is the advantage of spirochetes having endoflagella?
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-endoflagella is encased and they are not introducing the host immune response and you can avoid the host attacking you
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axial fibrils?
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-aka endoflagella
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What are insertion pores?
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located on endoflagella of spirochetes
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What makes differentiation of various spirochete genera difficult?
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-spirochetes are relatively inactive biochemically
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What features of spirochetes can be used to differentiate them?
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-length
-width -number of spirals -motility (pattern of motility) -silver nitrate staining |
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Describe which spirochete:
1. has the second longest wavelength 2. has the shortest wave period 3. has the longest wave period |
Longest wave: borrelia
second longest wave: treponema, serpulina, brachyspira shortest wavelength: leptospira |
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Which spirochete causes lyme disease?
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-borrelia burgdorferi
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What are two other spirochetes that have been found to cause lyme disease besides burdorferi?
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-garinii and afzelii
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How long is the life cycle of borrelia burgodorferi?
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-2 years
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What is another name for lyme disease caused by borrelia burgdorferi?
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-erythema cronicum migrans
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Describe the time course of lyme disease caused by borrelia burgdorferi a spirochete.
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Skin rash (2 mo)->heart (after 2 months)->nervous system (after 2 months)->chronic arthritis (after 8-10 months)
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What is the link between lyme disease and alzheimers?
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-cysts can be recovered from skin lesions, tonsils, and hippocampus of patients with concurrent alzheimers disease (AD) and lyme disease patients
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Why are borrelia cysts a problem?
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they can be reactivated to form the spial (spirochete) form of borrelia
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Describe vaccine development for borrelia burgdorferi.
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Outer surface protein A (OspA) was originally thought to be the one to target. But, transmission in the tick causes a change in the outer surface proteins (Osp) of the bacterium.
OspA (tick)-->OspC (host) unfed tick after feeding on blood Now vaccine design is focused on OspC bc of the blood meal that makes it express OspC on the surface, not A. |
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what is the predominate antigen form in infectious B. burgdorferi?
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-OspC
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what is the big concern with leptospira?
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-zoonotic
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Pathogenic organisms of leptospirosis are serovars of?
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-leptospira interrogans
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Nonpathogenic organisms of leptospira are serovars of?
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-leptospira biflexa
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How do you diagnose leptospirosis?
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-serology
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What is the difference between host adapted and nonhost adapted leptospira?
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1. host adapted: infection-->animal is reservoir, infection is endemic
2. non host adapted: infection-->accidental or incidental disease, sporadic infection or outbreaks, how humans contract disease |
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How is leptospira transmitted?
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-through urine of infected or carrier animals
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How does leptospira get into the body?
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-nasal, oral, conjunctival membranes or lesions
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Why is vasculitis caused by leptospira a problem?
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-leads to kidney and liver damage
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How does leptospira cause vasculitis?
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-during acute infection, leptospira multiply in the capillary endothelium, resulting in damage and vasculitis
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What are the clinical manifestations of leptospira secondary to?
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-vasculitis--afffects liver and kidney the most
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why is it important to pay attention to what lepto serovars are in dogs?
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-infecting serovars in humans are antigenically related to the emerging serovars in dogs
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What does leptospira look like under silver nitrate stain?
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-orange background and leptospira are little black organisms
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what are used for diagonsis of lepto in humans?
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-antibodies raised against leptospires are used in serological diagnosis
-antibodies can slow the growth of leptospira in the host, but do not kill th microbe |
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what kind of immune response does leptospira cause?
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-cell mediated immune response
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Cause of swine dysentery?
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-brachyspira hyodysenteria
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How do organism that cause swine dysentery stain?
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-B. hyodysetneria stains gram negative?
They have LPS, but they dont gram stain negative? |
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what kind of hemolysis does brachyspira dysenteria have?
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-beta hemolysis (looks like a cleared yellow area on blood agar)
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How do you contract swine dysentery?
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-disease contracted by ingestion of contaminated feces from other animals
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What age pigs will you see brachyspira dysenteria affect?
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-early post weaning/grower pigs
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Upon necropsy of a pig that has died from swine dysentery caused by brachyspira dysenteria, what will you note?
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-necrohemorrhagic enteritis or enterocolitis in the spiral colon
(think spiral colon=brachySPIRA) |
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What are two secondary agents of swine dysentery?
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1. bacteroides fragilis
2. fusobacterium necrophorum |
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How do you diagnose swine dysentery?
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-staining and serological testing
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How can you distinguish B. hyodysenteriae from B. innocens?
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-B. hyodysenteriae are longer and more loosely coiled than B. innocens, you may also have to use electron microscopy to tell the difference between the two
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B. pilosicoli (a spirochete) is associated with?
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-colonic spirochetosis (CS)
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What is CS?
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-colonic spirochetosis associated with B. pilosicoli (a spirochete) is characterized by END ON END epithelial attachment of brachyspira spirochetes alone or together with certain helicobacter species
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CS is accompanied by?
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-colonic spirochetosis-damage and inflammation of the colonic mucosal surface
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What does brachyspira pilosicoli do in growing pigs?
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-causes colitis (porcine colonic spirochetosis)
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What is porcine colonic spirochetosis characterized by?
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-variable increase in monocytes and neutrophils in the colonic mucosa
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How do spirochetes of porcine colonic spirochetosis attach?
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- END on END attachment to the luminal epithelium this is diagnostic on natural infection
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How can you distinguish B. pilocicoli from B. hyodysenteriae?
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-B. pilocicoli (the end on end ones causing colitis) are weakly beta hemolytic
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B. pilocicoli can infect what other species besides pigs?
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chickens
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See brachyspira pilocicoli and think...
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-end on end attachment/colitis in pigs
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what does treponmea cuniculi (a spirochete) cause?
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rabbit syphilis, a true VD
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How do you tell staph from strep?
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-morphology: staph=clusters, catalase positive
-strep=chains |
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Staph are catalase positive or negative?
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catalase positive, gram positive
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staph: motile or nonmotile?
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-nonmotile
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What kind o2 does staph like?
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-facultative anaerobe
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staph: sugar fermentor or nonfermentor?
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-surgar furmentor
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Doe staph produce any gas?
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-no
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This group of organisms are among the most hardy, most resistant to environmental stress of all of the non-spore forming organisms.
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-staphy: resist dehydration and heat resistant, tolerate many common disinfectants
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staph cause what kind of disease?
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-suppurative=pus forming disease
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what is the hallmark of staph infection?
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-abscess formation
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Intoxication of staph cause?
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-toxic shock syndrome (dogs and humans=think tampons)
-food poisoning (humans) |
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Why does staph aureus have a yellow/gold color?
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-due to production of beta carotene pigment
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How can beta carotene be a virulence factor of staph aureus?
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-conjugated diene that serves as an electron sick for reactive oxygen species (ROS)-can detoxify ROS
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What kinds of staph are consistently more resistant to phagocytic oxygen-dependent killing mechanism?
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-staphs that are pigmented are resistant to ROS
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You culture a teat and you would expect to see what kind of staph?
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-staph epidermidis
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Staph epidermidis: coagulase positive or negative?
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coagulase negative
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All staphs, except epidermidis are: coagulase positive or negative?
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-all are coagulase positive, except epidermidis which is negative
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Is staph epidermidis of high or low virulence?
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-low virulence, an opportunistic pathogen
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What is the most prevalent disease producing staph of dogs and other carnivores?
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-staph intermedius
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What do colonies of staph intermedius look like?
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-non pigmented, coagulase positive (like all staphs except epidermidis)
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what kind of hemolysis does staph intermedius have?
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-weakly beta hemolytic
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How can you differentiate S. aureus from staph intermedius?
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-ONPF and API staph tests
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Among staphylococci, what is the only one that is ONPG positive?
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-staph intermedius!!
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What is the cause of greasy pig disease?
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staph hyicus
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Are staph species very invasive?
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-no they are opportunistic pathogens
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How does staph multiply and spread?
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-Virulence factors:
1. protein A and polyuronic acid capsules: confer resistance to phagocytosis 2. carotenoids and catalase to counter oxidative burst 3. hyaluronidase, hydrolases, toxin production-host tissue necrosis and degradation-Coagulase ="walling off" nectrotic areas |
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What is a biofilm and which organism uses this?
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-biofilm: assemblage of microbes attached to a surface
-staphs use this |
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A client describes this to you over the phone-a local abscess, what organism would you think of?
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staph!
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How does the process of abscess formation work? And what organism is it associated with?
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-staph!
1. release of bacteria products=chemotactic for neutrophils 2. rapid and extensive infiltration of neutrophils=acute inflammation 3. neutrophils lysed by staph leukocidin and hemolysin 4. damaged neutrophils release lysosomal enzymes=surrounding tissue damage |
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What is another virulence factor of staph besides the fact that it can detox ROS?
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-protein A disrupts phagocytosis
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How does protein A of staph disrupt phagocytosis?
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Protein A matches the shape of the Immunoglobulin and masks staph from the PMN cell
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Staph aureus is the major cause of what problem in cattle?
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-mastitis
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Staph intermedius is the common cause of what in dogs?
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-canine pyoderma
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Staph intermedius causes canine pyoderma which causes what kind of infection?
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-staphylococcal cellulitis
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Endogenous Staph intermedius colonize what areas?
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-nasopharynx and skin
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when would you expect to see greasy pig caused by staph hyicus (age)?
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-1-7 week old piglets
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What is the mechanism of staph hyicus to cause greasy pig?
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-exofoliating toxin degrades desmoglein 1 and epithelial cells fall apart
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What is the human version of greasy pig called?
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-staphylococcal scalded skin syndrome
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What is toxic shock caused by and what are some symptoms?
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-caused by staph aureus
-fever, skin rash, hypotension and shock |
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what is the concept behind super antigen for toxic shock caused by staph aureus?
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superantigen binds to T cells and causes them to proliferate thus releasing excess cytokines, thus causes toxic shock
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what is the only antibiotic for MRSA?
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-vancomycin
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How can you distinguish staph from strep, besides their morphology?
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-staphs (except for epidermidis) are catalase positive and strep is catalase negative
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strep: fermentative or nonfermentative?
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-fermentative
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How does strep make ADP?
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-fermentative-converts pyruvate into lactate while oxidizing NADH to NAD under aerobic conditions
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Which strep leads to dental caries?
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-strep mutans
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what is a surface component of strep that increases its pathogenesis?
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-hyaluronic acid capsule
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Strep has surface fibrils composed of _________ for host cell attachment.
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fibrils composed of M proteins
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strep gram stain?
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-positive (have teichoic acid)
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what hemolysis does strep have?
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-alpha, beta, gamma and non-hemolytic
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Serology of strep is based on?
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-C carbohydrate and M protein (in fibrils for adhesion)
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What are two ways to diagnose strep and what does each mean?
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1. lancefield serological GROUPING: C-carbohydrate
2. lancefiled serological TYPING: M-protein |
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what is the cause of most strep infections?
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-opportunistic invasion caused by patient's indigenous flora
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Why are strep more invasive than staph?
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-streptokinase: inhibits walling off
-hyaluronidase: digests CT -DNAse: to thin out deposits of DNA leaking out from lysed inflammatory cells |
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Why do streps produce a thinner, spreading exudate rather than the thick pus of well localized abscesses like staph?
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-bc of DNAse, this makes it more invasive and spreading, also it inhibits walling off with streptokinase
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what kind of tissue damage does strep cause?
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-pyogenic similar to staph, it just isn't localized, suppurative disease, brings in lots of neutrophils
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How does streptolysin prevent walling off?
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-pore formation
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What causes strangles?
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-strep equi
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How is strangles transmitted?
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-horse to horse
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what is this:
Horse, appetite loss, fever 102, purulent discharge from nose, intermandibular area swollen, pharyngeal area is painful. |
-strangles, strep equi
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How can a horse that has had strangles before break with it again?
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strep equi can live in the guttural pouch and reinfect
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What are bastard strangles?
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-when abscessed form in areas toher than the neck region (ie thorax or abdomen)
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what is purpura hemorrhagica?
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occurs in recovering animals, a non-contagious, acute, frequently fatal, ALLERGIC complication (this differentiates it from strangles or bastard strangles)-ALLERGY TO STREPTOCOCCAL M-PROTEIN
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Describe the difference in apprearance of a horse with purpura hemorrhagica and a horse with strangles.
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strangles: nasal discharge and swelling around the throat latch
purpura: swelling on the masseter (like it is an infected tooth) and leg, there is still nasal discharge (he shows a buckskin horse) |
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what is the most common cause of mastitis worldwide?
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-strep agalactiae
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what kind of hemolysis does strep agalactiae have?
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-beta hemolytic
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What are two other streps that cause mastitis besides agalatiae?
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strep dysgalactiae and strep uberis
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What species does strep equisimilis affect?
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-pigs, not horses
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This is a strep commonly found with strep equi and is a widespread commensal in many animal species, and a common cause of wound infections in horses
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strep zooepidemicus
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This causes meningitis and septicemia in young pigs.
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strep suis
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What is so important about strep suis?
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-zoonotic
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What does strep suis do/cause?
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-causes toxic shock like syndrome (like with staph aureus)
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What are the two different types of suis and what are they based on?
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type I:baby pigs
type II: more virulent -based on capsular antigens |
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What causes swine strangles?
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strep porcinous
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what is the sequelae of strep throat?
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-acute rheumatic fever
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what happens with acute rheumatic fever?
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-antibodies which the immune system generates against the M proteins cross react with cardiac myofiber protein myosin and smooth muscle cells of arteries, inducing cytokine release and tissue destruction
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What is the flesh eating bacteria?
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-strep pyogenes, necrotizing fascitis
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superantigen is associated with what two types of bacteria?
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staph and strep
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where are bacilli on the dichotomous key?
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-gram positive
-catalase positive -motile (except bacillus anthracis) |
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Bacillus: aerobic or anaerobic?
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-aerobic, some facultative
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Bacillus: spore forming or non spore forming?
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-spore forming
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How does sporulation with bacilli work?
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chromosome replicates
spetum forms bacterium engulfs newly forming spore peptidoglycan deposited in bacterium protein coat forms around peptidoglycan of the endospore |
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Most bacilli are motile, the one exception is?
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-b. athracis
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B. cereus?
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-food safety hazard
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What are the two forms of B. cereus?
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1. Emetic form (short incubation)
2. Diarrheal form (long incubation) |
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why are food heated repeatedly more likely to have B. cereus?
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-spores of cereulide producing strains are more heat resistant. this my lead to enrichment of cereulide producers in food that are (repeatedly) heat treated
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How does B. athracis grow best?
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-anaerobically
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What kind of hemolysis does B. anthracis have?
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-non-hemolytic or narrow zone of hemolysis
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What morphological feature of B. anthracis helps you to diagnose it?
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-medusa head edges
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What is unique about B. anthracis among bacilli?
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-non-motile
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what kind of pathogen is B. anthracis?
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-frank pathogen
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what is the concern with a vet necropsying an animal with B. anthracis?
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-it's zoonotic
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What is the cause of "wool sorters diease"?
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B. anthracis
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What are the three forms of bacillus anthracis?
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1. peracute
2. acute 3. chronic (rare) |
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what is the cause of these symptoms:
sudden onset, high fever, bleeding from body openings, edema, peracute death in 1-2h, acute in less than 24 hours |
B. anthracis
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B. anthracis presents itself how in a horse?
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-colic, edematous swelling of the throat, neck and shoulders
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How does B. anthracis present in a dog or pig?
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-pharyngeal swelling, gastroenteritis
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What are the three presentations of B. anthracis in the human?
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1. cutaneous anthrax-malignant pustule
2. respiratory anthrax (woolsorters disease) 3. intestinal anthrax |
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What is the major virulence factor of bacillus anthracis?
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-capsule
-EXOTOXIN |
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What are the three components of exotoxin?
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I=edema factor
II=protective antigen III=lethal factor |
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What does LF+PA cause?
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Lethal factor and protective antigen=lethal activity
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What does EF +PA cause?
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edema factor and protective antigen=produce edema
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What does EF and LF cause?
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edema factor and lethal factor=inactive
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What does PA + LF +EF cause?
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protective antigen +lethal factor+edema factor=edema, necrosis and is lethal
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what does each, EF, PA and LF do to increase the virulence of B. anthracis?
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EF and PA increase cAMP-->local edema
LF and PA inhibit cell signalling by proteolytic degradation=cells death |
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Descibe the mechanism of action of B. anthracis toxin.
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-crazy diagram in notes
-basically there is formation of PA pore -tumor endothelial marker 8 and capillary morphogenesis protein 2 are invovled |
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What can be used as a vaccine for B. anthracis?
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-antibodies raised against factor II (PA-protective antigen)
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How do you treat for B. anthracis?
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-large doses of IV or oral antibiotics as early as possible
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Describe the molecular details of protective antigen function- and its potential for a new vaccine for B. anthracis.
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dominant negative PA (the phenotype of mutant protein is dominant, and expressed)
If PA subunits are present and LF or EF bind to the prepore and ther is low pH=pore formations If mutant-dominant negative PA, low pH=no poor formation |
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Corynebacterium: where on the dicotomous key?
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Gram positive, catalase positive, non-motile
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Corynebacterium: gram stain?
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gram positive (purple)
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corynebacterium: motility?
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nonmotile
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corynebacterium: catalase test?
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-catalase negative
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In corynebacterium, what gives it its characteristic brown spots at the end of the green rod?
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-old cells store inorganic phosphate, which appear as metachromatic granules when stained
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why is it interesting that corynebacterium are NOT acid fast?
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-because they have mycolic acid
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Corynebacterium: acid fast?
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-no! even though they have mycolic acids
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corynebacterium: spore forming?
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-no spores
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If swab a dog's skin and find that it has corynebacterium, can I tell the O that this is the cause of the dogs dermatitis for sure?
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-no. corynebacterium is a commensal of the skin and mucous membranes normally, so swabbing and finding it doesn't mean that is the cause of disease
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What is the cause of diphtheria in humans?
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Corynebacterium diphtheriae
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What is one word that can be used to describe the cells of corynebacterium?
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-diphtheroid
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A person tells you they have a soar throat, low grade fever, and an adherent membrane on the tonsils, pharynx and nasal cavity, what do they have?
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-corynebacterium diphtheriae, or diphtheria
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Systemic spread of diphtheria can cause?
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-myocarditis and polyneuritis
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What does the C. diptheriae secrete?
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-secretes neuraminidase to degrade sialic acid
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what does C. dipthereiae make that inactivates IgA?
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-makes diphthin (proease) that inactivates IgA
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What do the toxigenic strains of corynebacterium diphtheriae carry?
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-carry the tox gene, which resides on beta-phages; lysoegnization leads to toxigenicity
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where does the tox gene of corynebacterium diphtheriae reside?
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on beta-phages
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what leads to toxigenicity of corynebacterium diphtheriae?
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-lysogenization
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Why is diphtheria toxin such a threat to human health?
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-it is extremely potent (.1 microgram of toxin per kg is the lethal dose for a human)
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Diptheria toxin action is through?
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ADP ribosomal transferase
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The cause of caseous lymphadenitis?
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-corynebacterium pseudotuberculosis
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How is caseous lymphadenitis spread?
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-ingestion or mechanically by draining the material (esp with shearing sheep)
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What is the important virulence factor of caseous lymphadenitis caused by C. pseudotuberculosis?
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-phospholipase D/sphingomyelinase D; degrades mammalian cell membranes; antibodies against this are protective
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What are the two strains of corynebacterium pseudotuberculosis?
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1. wild-type strain: causes abscess formation at site of infection and spreads to regional lymph nodes
2. mutant strain: reduced ability to establish infection and cannot spread |
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Which of the following members does not belong to the CMN group? aka tell me which are the three that belong in the CMN group?
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C-corynebacterium (including rhodococcus)
M-mycobacterium N-nocardia |
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what is the cause of pizzle rot?
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C. renale
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what is pizzle rot?
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-combo of urine scald and bacterial growth on the prepuce
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which lives longer in the environment, C. pseudotuberculosis or C. renale?
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-C. pseudotuberculosis
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What is the pathogenesis of C. renale?
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-urease adapted for urinary tract; splits urea to ammonia and co2. Alkaline urine-organism can penetrate the renal epithelium
Ammonia causes prepuce irritation and ulceration-allows for colonization |
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-urease adapted for urinary tract; splits urea to ammonia and co2. Alkaline urine-organism can penetrate the renal epithelium
Ammonia causes prepuce irritation and ulceration-allows for colonization what is this organism? |
c. renale=pizzle rot
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Can you vaccinate against pizzle rot?
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-nope. keep your pizzles clean
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why is it thought that C. bovis may be a commensal?
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-it may aid in protection against more virulent pathogens
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This is a major puss former (absceses) in herbivores and mastitis in cows?
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arcanobacterium pyogenes
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What is/are the virulence factor(s) of arcanobacterium pyogenes?
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-produces a single hemolytic exotoxin-pyolysin (PLO)
-antibodies to PLO are passively protective |
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Where does rhodococcus fall on the dicotomous key?
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-same as corynebacterium (fits into CMN)
-non-motile, catalase positive, gram positive rods |
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How do you distinguish between corynebacterium and rhodococcus on a gram stain?
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corynebacterium: club shaped and in a palisade arrangment
rhodococcus: shorter |
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Why can rhodococcus be included in the CMN group?
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-has mycolic acid like the CMN
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What does rhodococcus look like on culture?
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-smooth, round colonies on blood agar that tend to coalesce
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When are rhodococcus acid fast and when are they not acid fast?
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-acid fast if bacteria are isolates from direct smears and fresh clinical isolates
-lost on subculture |
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If you are looking at two blood agar plates and trying to decide which one is corynebacterium and which is rhodococcus how can you tell them apart just by looking?
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corynebacterium colonies are much smaller than rhodococcus's big, round, white, milky looking colonies
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What causes foal pneumonia?
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rhodococcus equi
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How do foals get exposed to R. equi?
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-it is a normal commensal of fecal flora of horses-persists a long time on contaminated pasture
-one tablespoon of dusty contaminated soil kicked up can contain one million bacteria (picture Dr. Evil saying...One m-eeel-ion dollars) |
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You have an owner of a horse farm call in. She describes an 8 week old foal with upper respiratory issues, fever for the past day and a half, and she has done a test and noticed that the colostral antibodies are low in this foal, what does it have?
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foal pneumonia-R. equi (foals 4-12 weeks of age)
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What does foal pneumonia cause in the lungs?
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pyogranulomatous bronchopneumonia with extensive lung abscesses
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why is it often hard to notice foal pneumonia?
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often foals show no signs of illness but fever will appear vigorous
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why is R. equi so well adapted to evading the hosts immune system?
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macrophages the ingest R. equi do not undergo phagosome/lysosome fusion and exhibit irreversible damage
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R. equi not only causes pyogranulomatous mesenteric lymphadenitis in young foals, but it also causes?
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-ulcerative colitits
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what is the basis of pathogenesis of R. equi?
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-destroy alveolar macrophages
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The ability of R. equi to persist in macrophages correlates with the abscence of?
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-phagosome lysosome fusion and inhibition of the respiratory burst
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what are the main virulence factors of R. equi?
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-VapA (encodes a surface lipoprotein)
-VapC -VapH genes these are large virulence plasmid encoding several virulence factors -cholesterol oxidase=damages mammalian cell membranes (cholesterol is the major component of eukaryotic cells membranes) |
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Why are mutant strains of R. equi less virulent?
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-lack of intracellular survival
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What kind of immunity does R. equi cause?
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cell mediated immunity but humoral immunity is involved since passive immunity aids in preventing disease and severity of disease is inversely related to abundance of circulating antibody
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Where does erysipelothrix live on the dichotomous key?
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-gram positive, rod, catalase negative
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How do you distinguish between erysipelothrix and lactobacillus or A. pyogenes?
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-have to use molecular diagnostics
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E. rhusiopathiae: gram stain?
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gram positive
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E. rhusiopathiae: shape?
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rods (short rods)
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E. rhusiopathiae: oxygen?
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-aerobic, microaerophilic and maybe facultative
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How can you tell E. rhusiopathiae from listeria monocytogenes?
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E. rhusiopathiae: nonmotile, catalase negative
Listeria monocytogenes: motile and have flagella |
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What is the hemolytic pattern of E. rhusiopathiae?
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alpha, beta and gamma
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E. rhusiopathiae colony morphology?
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ACUTE: smooth=small, round, smooth, cells are homogenous
CHRONIC: rough=larger with irregular borders -pleiomorphic and filamentous |
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The cause of porcine erysipelas aka diamond skin disease?
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-Erysipelothrix rhusiopathiae
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How do pigs get erysipelas?
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-ingestion of contaminated feces or soil
-can also enter through skin scratched or puncture wounds |
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Why can erysipelas seem to spread so easily?
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-it is very stable
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What are the three forms of porcine erysipelas?
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1. acute
2. subacute 3. chronic |
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The acute form of procine erysipelas causes?
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septic embolic: pus containing bacteria circulates from one part of the body and causes occulusion of blood vessels in another part of the body
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what is the sequelae of porcine erysipelas in the acute and subacute forms?
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-endocarditis
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The chronic form of porcine erysipelas causes?
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-arthritis
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What is a proposed virulence factor of E. rhusiopathiae?
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-hyaluronidase: breaks down hyaluronic acid in joints and tissues=thus arthritis (what the chronic form does)
-Sialidase: like corynebacterium |
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You are doing a necropsy on a pig and you note that the spleen is very enlarged, has rolled, smooth edges, and is very dark, what might this pig have died of? what other features of the pig can you look at to decide the cause of death?
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-think erysipelas with the enlarged spleen, look at the hide to see if there are diamond shaped red patched on it
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Can you as a vet contract erysipelas from a pig you just necrospied?
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yep. it is zoonotic
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What can you use to treat a pig with erysipelas?
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-antibiotics are effective, can use penicillin, erythramycin or clindamycin
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Where does listeria live on the dichotomous key?
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gram positive, rod, catalase positive, motile=lives with bacillus
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what is the predominant pathogenic species of listeria in humans and animals?
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L. monocytogenes
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Listeria monocytogenes: oxygen?
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facultative
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Listeria monocytogenes: spores?
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non-sporulating
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Can you put a plate of listeria monocytogenes in the refrigerator and have it grow?
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-yep it grows well at refridgerator temps. This is the basis of a cold-enrichment technique
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Is pasteurization an effective way to get rid of listeria monocytogenes?
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-on in low bacterial cell density (remember it likes to be refrigerated)
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What test was originally developed to Id strep agalactiae but can also be used to id listeria monocytogenes?
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CAMP test
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On a farm where would you go to find listeria monocytogenes?
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-not the farmers refrigerator in his shop...look in the silage bc it is high in iron
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what is the disease caused by listeria monocytogenes?
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-listeriosis
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What are the four types of listeria monocytogenes infections in animals?
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1. intestinal
2. visceral or septicemic listeriosis 3. abortive 4. neural (encephalitic) |
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Which form of listeriosis is commonly seen in ruminants?
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-neural listeriosis, it is associated with feeding silage
-causes meningoencephalitis -"circling disease" |
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What are the stages of listeria infection?
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1. internalization
2. escape from phagolysosome 3. nucleation of actin filaments 4. cell to cell spread 5. membrane vacuole |
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What is a virulence factor of listeria?
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-iron sequestration=siderophores to chelate iron
-iron enhances growth in vitro |
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what can you use to treat listeria?
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-oral pen or tetracyclin or dexamethasone
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Where are mycobacterium and mycoplasma on the dichotomous key?
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they aren't there
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what is the unique feature of all of the CMN group members?
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-mycolic acids
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Why are mycolic acids (of the CMN group) so important?
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lipid richness confers:
1. hydrophobicity 2. reistance to acid and alkali 3. resistance to humoral defense mechanisms 4. resistance to common antibacterial treatments |
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The CMN group cell wall contains?
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cord factor: trehalose 6,6-dimycolae (TDM) which is one type of mycolic acid
-important in virulence causing a granulomatous reaction |
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Mycobacterium: acid staining?
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-acid fast
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Acid fast bacteria have what in their cell walls?
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-mycolic acid (thus all CMN group members are acid fast)
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What is the primary stain in acid fast staining?
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-carbol fuchsin-contains phenol to solublilize the cell wall
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What is used to increase stain penetration in the cause of acid fast staining?
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-heat
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What is used to decolorize after the primary stain in acid fast staining?
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-acid-alcohol
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what is the counterstain in acid fast staining?
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-methylene blue
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At the end of acid fast staining, cells that are acid fast will be what color?
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reddish pink
non acid fast=blue (counter stain=methylene blue) |
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Mycobacterium: motility?
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nonmotile
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Mycobacterium: shape?
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rods (small rods)
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Mycobacterium: oxygen?
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strict aerobes
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Mycobacterium: speed of growth?
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very slow
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Two media are used to grow mycobacterium, what are both media supplemented with?
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glycerol
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What is the common treatment to kill mycobacterium?
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1:1000 bleach and 2% NaOH
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What is the cause of human TB?
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mycobacterium tuberuclosis
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What is a characteristic response of M. tuberculosis?
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-granulomatous: made of dead macrophages, killed bacteria and live extracellular bacteria
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How is M. tubeculosis established within the body?
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1. M. tuberculosis is inhaled via aerosols into the lung, where they are internalized within alveolar macrophages
2. inside nonactivated macrophages mycobacteria resist destruction 3. macrophage action by T cell dependent cytokines 4. if immunodeficient (HIV/AIDS) T cell function is compromised, unrestricted growth within macrophages causes dissemination of tubercle bacilli |
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How does mycobacterium get engulfed and processed?
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1. entry into macrophage, TAC is recruited to the mycobacterial phagosome (picture a big, hispanic bouncer named "TACO" running over to kick myco out of a bar)
2. this leads to activation of calcium which activates phosphatase calcineurin 3. M. tuberculosis then secretes the acid phosphatase SapM (it starts to cry at the sight of the giant TACO man) and serine/threonine kinase PknG to prevent phagosome-lysosome fusion 4. activated calcineurin blocks phagosome-lysosome fusion, thereby allowing M. tuberculsosis survival ( the tears of myco fight off the binding of phagosome and lysosome coming together to beat him up and he lives) |
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Dissemination of M. tuberculosis leads to what kind of lesion?
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miliary tuberculosis
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Cause of tuberculosis in cattle?
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Mycobacterium bovis
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How can M. bovis spread?
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-airborne and in unpasteurized milk
-transmission congential or sexual in cattle |
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M. bovis on a farm, do you report it?
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-? dont think so, just mycobacterium aviu/ sub paratuberculosis?
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What happens to M. bovis reactive cattle?
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-slaughtered and extensive cleanup required
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why do you have to clean up so well after you find M. bovis positive cattle?
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M. bovis is very stable
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what is the cause of tuberculosis in birds?
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Mycobacterium avium complex
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why do we say that M. avium COMPLEX causes bird tb?
|
-it includes more than one mycobacterium:
avium, paratuberculosis (johnes), hominis (human) |
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How can pigs get TB?
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wild birds
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How do you diagnose M. avium complex?
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-acid-fast staining and culture
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Why is it hard to kill M. avium complex?
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-organism is resistant to standard anti-mycobacterial treatment
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Is Johne's reportable?
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-yep
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what does Johne's cause in cattle?
|
-chronic enteritis and severe diarrhea
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If you necropsy a cow and you find that the ileum and colon are involved and the farmer gave a history of severe diarrhea and general wasting away, what do you diagnose?
|
-Johne's disease, ileum and colon are usually involved
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Are the organisms that cause Johne's acid fast?
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yes. M. paratuberculosis is acid fast
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what mycobacterium infects humans and is carried by nine-banded armadillo?
|
M. leprae
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why is it difficult to kill mycobacterium diseases?
|
-resistant to many common antibiotics
-exists inmany contexts in the body making treatment challenging (intracelluar, extracellular and caseous lesions) -each mycobacterium population has a different metabolic rate and rate of replication |
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What are the two types of parasitism with obligate intracellular bacteria?
|
extracellular pathogens:
intracellular pathogens: multiply within phagocytes cause chronic disease that is recrudescent (recurring disease) -this distinction is based on fate after phagocytosis |
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Do intracellular pathogens ever clear?
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no. that is why they are recrudescent
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What parasites are restricted to intracellular habitat? and what are two examples?
|
True obligate intracellular parasites are restricted to intracellular habitats
-rickettsiae and chlamydiae |
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What parasites can grow either extra or intracellularly? waht are some examples?
|
Facultative intracellular parasites
-grow within professional phagocytes -chronic and/or recurrent disease: ie. TB, Johnes, brucellosis |
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Describe the survival strategy of intracellular bacteria and coping with phagocytosis/endocytosis.
|
1. recognition and attachment
2. internalization (endocytosis) 3. phagosome-lysosome fusion, degranulation or 4. (degranulation) and killing |
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Two types of kill of intracellular pathogens?
|
1. oxygen dependent-respiratory burst
2. oxygen independent-proteases, lysozymes, lactoferrin, defensins |
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what drives the respiratory burst?
|
NADPH oxidase complex
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what are the four ROS that are the result of a respiratory burst?
|
1. singlet oxygen
2. hydrogen peroxide 3. hypochlorite (bleach) 4. hydroxyl radical |
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why can obligate intracellular bacteria survive better?
|
-not as much superoxide?
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How do intracellular pathogens keep the production of PMN O2- low?
|
-bacterial acid phosphatase blocks neutrophil superoxide production
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where does rickettsiae multiply and spread?
|
-obligate intracellular parasites of reticulo-endothelial and vascular endothelial cells or leukocytes
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What are "RE" cells?
|
-reticulo-endothelial
-cells are phagocytic cells located in reticular connective tissue, primarily monocytes and macrophages. These cells accumulate in lymph nodes and the spleen |
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what is the source of energy for rickettsia metabolism?
|
-glutamate (major substrate for energy production)
-glutamine (second most important ATP yielding substrate) |
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How do rickettsia generate energy?
|
-glutamine-->glutamate-->transamination-->aspartate and alpha ketoglutarate-->TCA cycle-->NADH to NAD-->ETC-->ADP to ATP
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what causes typhus?
|
ricketssia prowazekii
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What causes Rocky Mountain Spotted Fever?
|
Rickettsia rickettsii
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Your neighbor tells you that she has been suffering form a skin rash, difficulty swallowing (dyspnea), hypotension, she has even had seizures and delirium and her docs can figure out what it is, the put her on phenobarbital and sent her home, what does she have and what is causing it?
|
Rocky mountain spotted fever caused by rickettsia rickettsii
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what is the major resulting issue of rickettsia that can cause damage?
|
capillary thromib
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What happens to RBCs when you have rickettsia?
|
-hemorrhage
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What is the only antibiotic that can be used to treat rickettsia?
|
tetracyclin
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How does one encounter ehrlichia?
|
-brown dog tick
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|
Here are the clinical signs:
pan-cytopenia esp thrombocytopenia (reduction in platelets), epistaxis (nose bleeding), hypergammaglobinemia, lymphadenopathy, increased RBC sedimentation rate (anemia)...what is it? |
ehrlichia
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What cause equine ehrlichiosis?
|
Ehrlichia equi (same as in dogs)
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What causes canine salmon poisoning?
|
-Neorickettsia helminthoeca
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What is the life cycle of Neorickettsia helminothoeca?
|
-gets in snail, snail eaten may salmon, salmon eaten by dog
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You are necropsying a dog that has a history of: lived in pacific northwest, sever dehydration, blood loss and shock and died within 14 days of the first symptoms of lethargy and dehydration, what killed it?
|
-neorickettsia helminothoeca
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What is the ab of choice for neorickettsia helminothoeca?
|
tetracycline
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|
what is the cause of Potomac Horse Fever?
|
Ehrlichia risticii
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You have a horse with anorexia, fever, depression, leukopenia, explosive diarrhea, dehydration and terminal shock, what is the cause?
|
-Ehrlichia risticii
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This organism can cause massive infections of placentas in cows, sheep, and goats leading to abortions.
|
Coxiella burnettii
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How does Coxiella burnettii differ from Rickettsia?
|
arthropod vector not necessary for Coxiella burnettii, direct contact, inhalation of contaminated dust, usually unstable in host cells, NO RASH, infect macrophages rather than endothelia
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what is the target cell of anaplasmataceae?
|
-RBC is the target cell
|
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what is the cause:
severe anemia, depression, inappetance, fever, dehydration, die from hypoxia when handled. |
anaplasmataceae
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what is the cause of anaplasmosis?
|
-anaplasmataceae (tick transmission)
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How do you diagnose anaplasma marginale?
|
-blood smear or special stains
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If you are looking at a blood smear and you notice bacteria that appear to be located on the margin/edge of infected RBCs, what is the bacteria?
|
-anaplasma MARGINALE (get it? margins, marginale?)
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what stain would you want to use for anaplasma marginale and what would you expect to see if it is anaplasma marginale?
|
-use acridine orange
-anaplasma will be the little brown dot on the edges of yellow/green blobs that are the RBCs |
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Treatement of anaplasma?
|
tetracyclin
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Why are cases of co-infection of anaplasma and something else being diagnosed in the last decade?
|
-ticks carry multiple infectious agents
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where would you find hemobartonella when you look at it under the scope?
|
-on the edges of RBCs just like anaplasma
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What the infectious and the non-infectious forms of chlamydia?
|
infectious: elementary bodies
noninfectious: reticulate or initial bodies |
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|
what is the life cycle of chlamydia?
|
1. elementary body entry
2. conversion of elementary body to reticulate body 3. multiplication of reticulate body 4. conversion of reticulate body to elementary body 5. elementary body and reticulate body within the cell 6. cell lysis, process starts all over again |
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|
what does chlamydia form in epithelial cells?
|
-form membrane inclusion bodies
|
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How does chlamydia contrast to rickettsia?
|
-chlamydia are not free in cytoplasm
-rickettsia is free in cytoplasm |
|
|
what is one virulence factor of chlamydia?
|
-unique cell wall
-contains LPS but lacks peptidoglycan instead it consists of a major outer membrane protein cross linked with disulfide bonds (p layer) |
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|
What is the cause of psittacosis in birds?
|
chlamydophila psittaci
|
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|
A bird is refusing to eat, has yellowish-green diarrhea, has mucus and pus nasal discharge, eyes are pasted shut with exudate, the keel is very prominent, and the bird is dehydrated, what is the cause?
|
chamydophila psittaci
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Treatment for chlamydophila psittaci?
|
tetracyclin, pen is ineffective!
|
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|
This causes infection and inflammation in the fallopian tube and PID, what is it?
|
chlamydia trachomatis (gross...)
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|
What is the cause of cat scratch fever? duh, dum, dah!
|
bartonella henselae
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