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157 Cards in this Set
- Front
- Back
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What stain is used to visualize spirochetes spp?
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Warthin-Starry (sliver nitrate) stain
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How is darkfield microscopy advantageous for visualizing Spirochetes spp?
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Enhances the contrast in unstained specimens
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What is unique about Spirochete flagella and how is this advantageous?
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Endoflagella: encapsulated within the cell envelope
prevents recognition of flagellar antigens |
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Describe Borellia cell morphology in regards to spirals
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4-8 spirals per cell; very loose spirals
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Describe Leptospira cell morphology in regards to spirals
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many fine, tight spirals
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Describe Trepenema, serpulina, brachyspira cell morphologies in regards to spirals
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6-14 spirals per cell; regular and angular
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The deer tick transmits which bacteria to which hosts?
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Borellia burgdorferi;
Transmitted to dogs, cats, humans, horses, cattle |
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Borellia burgdorferi causes which disease?
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Lyme disease
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Which culture medium is used to grow Borellia burgdorferi?
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BSK-II
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Which are the infective forms of the tick that transmits Lyme disease? (choose all that apply)
eggs, larvae, nymphs, adults |
nymphs, adults (adults are less virulent)
larvae is the life stage that picks up the bacteria (but is not an infective stage) |
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How many seasons must pass between a tick hatching to the point of becoming infective? When in the life cycle are eggs laid?
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4 seasons (one year--spring to spring);
Eggs are laid in the adult's third spring |
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Under what conditions do Borellia burgdorferi form cysts?
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unsatisfactory culture conditions, presence of antibiotics
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OspA is expressed when Borellia burgdorferi is in the _________ and OspC is expressed when in the _______
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tick; host
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Outer surface protein C (OspC) can be exploited for what purpose?
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Development of vaccines against Borellia burgdorferi
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Do host-adapted or non-host adapted strains of Leptospira create reservoirs and endemic diease?
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Host-adapted strains
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What is the most common zoonosis studied so far?
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Leptospirosis
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How do animals encounter Leptospira?
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from urine of infected rats, cattle, dogs, squirrels, skunks, possums
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Which organ systems can be affected by leptospirosis?
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Kidney--interstitial nephritis, tubular necrosis, impaired capillary permeability
liver, lungs, skin, skeletal muscle, vascular system also affected |
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Which serovar of Leptospira is infective in dogs?
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L. interrogans serovar canicola
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How are canine infections of leptospirosis important for human medicine?
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highly zoonotic, more dogs in suburban areas are contracting the disease, human serovars are related to canine serovars; dogs are the sentinel species
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What is the main cause of swine dysentery?
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Brachyspira hyodysenteriae (a spirochete)
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What are the secondary infective agents of swine dysentery?
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Bacteroides fragilis
Fusobacterium necrophorum |
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What disease is caused by Brachyspira pilosicoli?
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colonic spirochetosis
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How can Brachyspira pilosicoli be indentified in vivo?
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bacteria arranged end-on-end
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Give the catalase results:
Staph Strep |
Staph: catalase positive
Strep: catalase negative |
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What is the hallmark Staphylococcus infection?
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abscess formation
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What toxins do Staphylococci use to lyse neutrophils during abscess formation?
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leukocidin and hemolysins
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Which Staphylococcal enzyme leads to "walling off" of an infection?
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Staph coagulase
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What is the virulence mechanism of the yellow color of some Staphylococcus strains?
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beta-carotene can serve as an electron sink which provides the bacteria with a method of energy absorption; may prevent oxygen-dependent phagocytosis
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How is Staphylococcus encountered?
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it is a commensal of the skin, teats, hair, superficial mucosa
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Protein A and polyuric capsules of Staph provide what advantage?
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prevent phagocytosis
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Coagulase, hyaluronidase and hydrolase provide what advantage to Staph spp?
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promote tissue necrosis which may prevent host immune response
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Which enzymes confers penicillin resistance for Staph spp?
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beta-lactamases
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How does Protein A in Staph spp. prevent phagocytosis?
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Protein A binds IgG in the wrong direction which prevents PMN recognition of bacterium (prevention of opsonization)
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Staphylococcus aureus causes what kind of lesions in cattle?
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supperative lesions in mammary gland epithelium
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Which bacterial toxin causes Scalded Skin Syndrome?
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Staphylococcus aureus exfoliating toxin causes spontaneous exfoliation of the skin
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Which bacteria produces toxic shock syndrome -1 (TSS-1) and what mediators are released?
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Staphylococcus aureus; the superantigen causes release of IL-1
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Which antibacterial may still be effective in killing off a chronic Staph infection?
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vancomycin; resistant to almost all antibiotics
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How do you differentiate S. aureus from S. intermedius? What is this testing for?
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S. aureus is ONPG -
S. intermedius is ONPG + Testing for the presence of beta-galactosidase (exam question) |
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Canine pyoderma can be caused by which bacteria?
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Staphylococcus intermedius
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Which bacteria cause greasy pig disease?
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Staphylococcus hyicus
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How does exfoliating toxin of Staphylococcus actually work?
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Degradation of desmoglein 1
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What is unique about cell division of Streptococci spp.?
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divide in the same plane making strips of cells
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What advantage does hyaluronic acid confer on Strep spp?
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creates an anti-phagocytic capsule
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What advantage do surface fibrils (M proteins) confer on Strep spp.?
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provide adherence to host tissues
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What 3 methods are used to classify Strep spp?
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hemolytic pattern, Lancefield Serological grouping (C-Carbohydrate), serological typing (M proteins)
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Which groups of Strep spp. are of veterinary importance?
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Groups B, C, D, G
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What cell components of Strep are required for adhesion to host tissues?
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M protien, fibronectin binding protein, hyaluronic capsule
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Which is more invasive, Strep or Staph?
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Streptococci are more invasive
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What is the role of streptokinase?
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converts plasminogen to plasmin which can digest fibrin thus inhibiting the "walling off" process
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What is the role of hyaluronidase in Streptococci virulence?
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digests connective tissue to help aid spread
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What is the role of DNAase in Streptococci virulence?
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breaks down DNA released from lysed cells; makes the area less viscous so bacteria can better spread
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T/F Streptococcal infections create a thick, viscous pus
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False; Strep creates a thin, spreading exudate that allows for easy spread of the bacteria
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Streptolysins O and S have what role in Streptococcal infections?
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form pores in PMNs by binding to cholesterol in their membranes
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Streptococcus agalactiae causes what disease and in which animals?
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mastitis in cattle, sheep, goats
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T/F Streptococcus equi may be encountered orally, nasally, transmammary, by ingestion, by aerosols, or flies
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True: all of these are forms of encounter
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Where in the host does S. equi first adhere?
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to epithelial cells in the oropharynx
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How does S. equi spread throughout the host?
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via draining lymph nodes, especially submandibular and retropharyngeal (Strangles)
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What is the cause of bastard strangles?
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Abscess formation in lymph nodes throughout the entire body due to migrating S. equi
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What are some suspected virulence mechanisms of S. equi?
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streptolysins (kill phagocytes); hyaluronic capsule and M proteins (inhibit phagocytosis)
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What disease is described?
rapid, noisy breathing; fever; inflammation of nasal mucosa; intermandibular swelling; pharyngeal pain; purulent nasal discharge |
Equine strangles
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Why does purpera hemorrhagica develop in a horse with strangles?
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immune reaction to M protein on the surface of S. equi
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What is the best vaccination plan for preventing strangles?
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vaccinate the pregnant mare 12 hours prior to foaling; vaccinate foal at 2-3 months of age
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Match these Streptococcus suis capsular types to the correct age group:
type 1, type 2; 4-12 weeks, baby pigs |
Type 1: baby pigs
Type 2: 4-12 week old pigs |
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What diseases can Streptococcus suis cause?
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septicemia and meningitis in young pigs
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What type of disease is seen in humans from Streptococcus suis infection?
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Toxic shock-like syndrome
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How does acute rheumatic fever develop in humans?
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sequelae to strep throat; antibodies generated against M protein begin to attack cardiac myofibers and smooth muscle cells (autoimmune)
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T/F Streptococcus pyogenes causes necrotizing fasctitis in horses.
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False; S. pyogenes is a group A Strep, so it causes necrotizing fascitis in humans
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What is Spe?
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Spe is a superantigen produced by Streptococcus pyogenes that causes necrotizing fascitis
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Put these in order (Bacillus sporulation)
cell lysis, DNA replication, septum formation, protein coat formation, DNA lysis, peptidoglycan layering |
DNA replication, septum formation, peptidoglycan layering, DNA lysis, protein coat formation, cell lysis
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How does Bacillus cereus cause food poisoning?
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forms spores under aerobic conditions, occurs when prepared foods aren't refrigerated well
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match: emetic food poisoning, diarrheal food poisoning; long incubation period, short incubation period
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emetic: short period
diarrheal: long period |
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Which bacteria has a "medusa head" appearance to the edge of the colony? What else makes this colony unique looking?
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Bacillus anthracis; ground glass appearance
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T/F Bacillus cereus causes wool sorters disease
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False; B. antracis causes this disease
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Name the three forms of Bacillus anthracis infections (time frame)
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acute
peracute chronic |
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Name the three presentations of Bacillus anthracis infections.
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cutaneous: malignant pustule
respiratory: hemorrhagic, progressive intestinal: vomiting blood, enteritis, GI difficulty |
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Name the three components of exotoxin of Bacillus anthracis
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Edema factor (EF)
Protective Antigen (PA) Lethal Factor (LF) |
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Give the results of these combinations of exotoxin components of Bacillus:
LF +PA = ; EF +PA = ; EF +LF= ; EF + LF +PA= |
LF +PA = lethal
EF +PA = edema EF +LF= no effect EF + LF +PA= edema, necrosis, lethal |
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What role does PA have in infection by Bacillus anthracis?
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creates tumor endothelial marker 8/capillary morphogenesis protein 2 subunits on the host cell surface; aggregates of subunits allow LF or EF binding
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What is the role of EF in Bacillus anthracis infections?
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increases production of cAMP
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What is the role of LF in Bacillus anthracis infections?
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inhibits production of MAPKK
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What is the basis of PA mutant dominant negative vaccines against Bacillus anthracis?
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a mutant PA is expressed which doesn't allow proper host cell binding, so the process of infection (pore formation) is stopped from the beginning
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What antibiotics should be used for Bacillus anthracis infections?
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large dose oral and IV fluorquinolones may work for peracute infections and cutaneous infections
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Which bacteria comprise the CMN group?
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Corynebacteria, Mycobacteria, Norcardia, Rhodococcus
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Is Rhodococcus a CMN group bacteria?
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Yes; it has mycolic acids in its cell wall
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What is unique about CMN bacteria?
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all have mycolic acid in their cell wall
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Dividing cells of which bacteria have a palasaides pattern?
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Corynebacterium (Y, V, L shapes)
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T/F Corynebacteria are acid-fast
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False; non-acid fast even though they contain mycolic acids
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Corynebacterium diphtheriae causes what clinical signs?
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low fever; pseudomembrane over throat/tonsils/nasopharynx; sore throat
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What is the basic mechanism of action of diphtheriae toxin?
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ADP ribosylation to inactivate translation factors in host cells
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Why is iron important for Corynebacterium diphtheriae virulence?
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toxin synthesis is regulated by iron availability (low iron-->high toxin synthesis to destroy cells and free up more iron)
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What bacteria causes a caseous lymphadenitis?
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Corynebacterium pseudotuberculosis
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What is the function of phospholipase D and sphingomylenase D in Corynebacterium pseudotuberculosis infections?
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degradation of mammalian cell membranes
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Which diseases can be caused by Corynebacterium renale?
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pizzle rot, pyelonephritis, urethritis, cystitis
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How is Corynebacterium renale transmitted?
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via splashing of contaminated urine
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Describe the pathogenesis of pizzle rot.
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Urease in C. renale splits urea to ammonia and CO2-->urine becomes alkalinized-->bacteria can better penetrate renal epithelium; ulceration of prepuce allows better colonization
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What disease is caused by Arcanobacterium pyogenes?
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causes mastitis in herbivores
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What disease is described? Which bacteria?
foal; diffuse bronchial sounds-->cough-->wheeze-->crackling lung sounds; fever; increased respiratory rate |
foal pneumonia; Rhodococcus equi
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Why is it difficult to detect a Rhodococcus equi infection?
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foal becomes critically ill before clinical signs develop; only show weakness after exercise/excitement
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Describe the pathology of an enteric infection of Rhodococcus equi.
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pyogranulomatous mesenteric lymphadenitis and ulcerative colitis
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What are the dangers of hematogenous spread of Rhodococcus equi?
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multiorgan involvement, abortion, placentitis
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What are some virulence factors of Rhodococcus equi?
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inhibition of phagosome-lysosome fusion and respiratory burst; plasmid encoded virulence proteins; cholesterol oxidase
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Which bacteria studied commonly is found in fish, crustaceans and rodents and in decomposing organic matter?
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Erysipelothrix spp.
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How can you differentiate between Erysipelothrix and Listeria?
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Listeria is catalase postive and motile
Erysipelothrix is catalase negative and non-motile |
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T/F Erysipelothrix cells are filamentous and only found as rods
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False; they are filamentous, but are highly pleiomorphic
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What is porcine erisepelas and what bacteria causes it?
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Diamond skin disease; caused by Erysipelothrix
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What causes the diamond pattern seen on the skin of swine with diamond skin disease? (pathogenesis)
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infarcts in the skin due to occlusion of capillary supply
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How does Erysipelothrix enter a host?
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puncture wounds/scratches in skin; ingestion of contaminated feces or soil
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How do septicemic animals shed Erysipelothrix?
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in urine, feces, vomit, saliva
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T/F An animal can carry an Erysipelothrix infection and be asymptomatic
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True; some animals are asymptomatic but carry large numbers of bacteria
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What are some sequelae to Erysipelothrix infections?
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septic emboli, endocarditis, non-supperative arthritis (fibrinous synovitis)
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Name two virulence factors of Erysipelothrix.
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hyaluronidase (causes arthritis)
sialidase (aids in bacterial spread) |
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What forms does a human infection of Erysipelothrix take on?
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vasculitis (localized cutaneous reaction, severe generalized cutaneous reaction), arthritis, septicemia
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Which bacterial growth will be enriched when a culture is grown in a refrigerator?
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Listeria spp. grows well in cold temperatures while other bacteria do not
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T/F Listeria is CAMP positive so the result is an inhibition of hemolysis.
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False; Listeria is CAMP positive, but this will result in an arrowhead pattern of hemolysis
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What is the result of a reverse CAMP test using S. aureus and Corynebacterium pseudotuberculosis?
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inhibition of hemolytic activity of S. aureus
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In which tissue types are you most likely to find Listeria?
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Placenta and CNS
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How does Listeria enter a host?
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ingestion of contaminated silage; direct infection of conjunctiva
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Name the four types of listerioses.
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Intestinal
Visceral/septicemic Abortive (placentitis) Neural (circling disease) |
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Why is Listeria a common cause of food poisoning in humans?
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Listeria can grow well at very low temperatures, so refrigeration is not sufficient to prevent bacterial growth
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Which groups of humans are at the greatest risk for food poisoning caused by listeriosis?
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neonates, pregnant women, elderly
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T/F Listeria are found intracellularly
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True; Listeria exist within host cells and can be transferred between cells without ever being exposed to the outside environment
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Internalin serves what purpose for Listeria cells?
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Allows for adherence to epithelial cells via E cadhearin which leads to phagocytosis of the bacterium
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What does listeriolysin O do in the process of cell-to-cell transfer of Listeria?
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mediates lysis of phagosome that contains the engulfed bacteria
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What does ActA do in the process of cell-to-cell transfer of Listeria?
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activates actin filaments which then propel the bacterium toward the host cell surface
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What does Phospholipase C do in the process of cell-to-cell transfer of Listeria?
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Lyses the double membrane that contains the newly engulfed bacteria (within the new host cell)
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T/F A host that has low iron levels will be more susceptible to a virulent infection of Listeria
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False; Listeria needs iron for survival and virulence, so if a host does not have high iron levels, the bacteria cannot be very virulent
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What do Listeria use to accumulate iron stores?
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siderophores--iron chelators
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Is a Listeria infection relatively easy or difficult to clear from the host? why?
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Difficult: only a small number of bacteria are needed to infect the host; Listeria lives within host cells, so they are not easy to kill
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Explain how acid-fast staining works in an acid-fast cell.
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Carbol-fuschin is retained in the cell wall of CMN group bacteria due to high mycolic acid-->decolorization doesn't remove the stain-->cells remain reddish-pink
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How can Mycobacterium growth be enriched in culture?
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Mycobacterium are resistant to acid and alkali while other cells are not.
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Which bacteria grows in serpentine cords? What causes this and why does it matter?
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Mycobacterium;
cord factor--it confers toxicity and creates granulomas |
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Which bacteria grows the slowest of those studied? What special requirement does it have?
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Mycobacterium; Mycobactin (iron chelator); must be grown with acid or alkali to prevent overgrowth by other bacteria
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How does Mycobacterium prevent phagosome-lysosome fusion?
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inhibition of TACO removal from the phagosome prevents phagosome-lysosome fusion
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Put these layers of Mycobacterium-induced granuloma in order (inner to outer):
lymphocytes; inactivated macrophages; dying macrophages |
inactivated macrophages
dying macrophages lymphocytes |
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What is miliary tuberculosis?
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formation of tubercules in areas distant to the primarily infected areas
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What disease is caused by Mycobacterium avium subspecies paratuberculosis?
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Johne's disease in cattle
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What are the clinical manifestations of Johne's disease in cattle?
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rough, corrugated intestinal mucosa; chronic enteritis; severe diarrhea
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What is the cause of death in cattle affected by Johne's disease?
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malabsorption of nutrients
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T/F Mycobacterial infections are difficult to treat
Give reasons for your answer |
True; bacteria exist within host cells; cell wall doesn't allow drug penetration; long course of treatment required; lack of effective vaccines
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Name two obligate intracellular bacteria.
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Rickettsiae, Chlamydiae
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What is unique about obligate intracellular bacterial reproduction?
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The bacteria must be inside the host cell phagosome to reproduce
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Oxygen-dependent killing requires what enzyme to produce oxygen free radicals?
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NADPH oxidase
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What enzymes are used in oxygen-independent killing?
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proteases, defensins, lysozymes, lactoferrin
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What role does acid phosphatase play for the survival of obligate intracellular pathogens?
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acid phosphatase prevents neutrophil production of superoxide free radicals, so the chain reaction of free radical production (respiratory burst) cannot be initiated
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What is recrudescence? Why does it occur with obligate intracellular pathogens?
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a re-emergence of an infection after a period of inactivity. It occurs with intracellular bacteria because they are never completely cleared from host cells
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How are the Rickettsiaciae bacteria spread?
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vector borne: fleas, lice, ticks
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Where in the host do Rickettciaciae multiply?
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in reticuloendothelial cells, vascular endothelial cells, leukocytes
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Why is glutamate important for Rickettsiaciae survival?
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glutamate is the main substrate for ATP production
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What diseases are caused by the Rickettsiaciae? Why is this important to know?
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typhus, rocky mountain spotted fever; while animals are not clinically infected, they serve as reservoir hosts for human infections
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What should be used to treat a rickettsial infection? (this is a test question)
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tetracycline
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How is Erlichia transmitted between hosts?
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vector-borne; brown dog tick
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What cells are the target of an Erlichia infection?
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white blood cells (not endothelial cells as in rickettsial infections)
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What causes Potomic Horse Fever?
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Erlichia risticii (lethargy, fever, leukopenia, explosive diarrhea)
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What are the clinical signs of canine erlichiosis?
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Pancytopenia
epistaxis hypergammaglobulinemia lymphadenopathy anemia |
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Which bacteria are common causes of bovine mastitis?
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Staphylococcus aureus, Streptococcus agalactiae, coliforms (E.coli, Kelbsiella, Enterobacter), Corynebacterium bovis
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T/F A milk sample with 450,000 somatic cells is considered a good sample.
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False; counts this high indicate a problem
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