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59 Cards in this Set

  • Front
  • Back
Clostridium, general properties
Obligate anaerobic
Gm+ rods
Spore forming
Catalase/ oxidase negative
Toxin producing
Clostridium botulinum, food botulism
-think canned foods
-toxin is heat-labile
-toxin is two subunit, and there are 7 types
-toxin enters nerve cell and blocks release of acetylcholine, leading to flaccid paralysis; think "botox"
-motor, not sensory
-Dx: clinical or detect toxin
-Tx: horse serum antitoxin, toxin type specific
Clostridum tetani
-terminal spores diagnostic
-only one serological type
-neurotoxin inhibits neurotransmitters, resulting in spastic paralysis: convulsive contractions i.e. locked jaw
-motor, not sensory
-Dx: clinical
-Tx: antitoxin, penicillin, immunization with tetanus toxoid (TDAP)
Clostridum difficile
-toxins A&B
-diarrhea with pseudomembranes
-Dx: history of antibiotic use, ELISA for toxins, visualization of pseudomembranes
-Tx: metronidazole or vancomycin
-Prophylaxis: prudent use of antibiotics
Clostridum perfringens
-tissue necrosis
-alpha toxin (lecithinase) damages host cell membrane
-byproducts are gases (H2 and CO2)
-Dx: crepitus upon pressing the skin due to gas in subcu or muscle
-Tx: surgical, penicillin
Clostridum toxins
Botulism: flaccid paralysis
Tetanus: tetanus (locked jaw)
Exotoxins A & B: diarrhea in pseudomembranous colitis due to difficile
Alpha toxin: cause of "gas gangrene" due to perfringens
Clostridium botulinum, subsets
A. Infant botulism
-honey common source
-symptoms more subtle: constipation, flaccid head control, CN deficit
B. Wound-associated botulism
-spores germinate in wound and produce toxin
Anaerobes, overview
Gm+ rods: Proprionibacterium, antinomyces
Gm- rods: Bacteroides, fusobacterium, prevotella, porphyromonas
Gm+ cocci: Peptostreptococcus
Spores: Clostridium
Anaerobes, antibiotics
Penicillin except against Bacteroides fragilis
-use penicillin for anaerobes above the diaphragm
-clindamycin and cefoxitin against B. fragilis
Eikenella corrodens
Penicllin sensitive, aerobic Gm- rod causing human bite infections
Actinomyces
-Gm+ rods
-sulfur granules
-oral, facial, pharynx, GI
Streptococcus viridans
-oral flora
-Gm+ cocci, gamma-hemolytic
-cause of dental plaques
-most common cause of subacute endocarditis
Diphtheroids
-oral flora
-Gm+ rods
Fusobacterium
-needle-like Gm- rods
-penicillin sensitive
-obligate anaerobe, very
-oral flora
Prevotella melaninogenicus
-Gm- rods
-very sensitive to oxygen
-requires hemin
-produces black pigment on blood agar plates
-penicillin sensitive
-oral infections
Porphyromonas (gingivalis)
-Gm- rods
-uses hemin
-brown/black pigment on blood agar plate
-penicillin sensitive
-cause of gingivitis
Peptostreptococcus
-Gm+ cocci
-flora in mouth, GI, and urogenital tracts
B. fragilis
-anaerobic Gm- rod
-oxygen tolerant
-below the diaphragm
-penicillin resistant
Bifidobacterium
-anaerobic Gm+ rods
-flora of GI
-sensitive to penicillin
-generally not pathogenic
Lactobacillus
-anaerobic Gm+ rods
-non-pathogen
-maintains an acidic pH in the colon
-flora of GI
Flora, respiratory tract
-Eikenella corrodens (thoat)
-Staph aureus (nose)
Flora, female genitourinary tract
-fecal flora
-lactobacillus
-Group B strep
Flora, skin
Staph epidermidis
Staph aureus
Diphteroids
Proprionibacterium (acnes species implicated in acne)
Peptococcus
Flora, GI
-bacteroides
-bifidobacterium
-lactobacilli
-clostridium
-coliforms
-enterococcus
-remember abnormal bacterial overgrowth may convert conjugated bile acid to free bile acid, causing fat malabsorption
Flora, oral
-Staph epidermidis (oral)
-Neisseria (oral)
-Strep viridans (oral)
-Fusobacterium (oral)
-Prevotella (oral)
Peptostreptococcus (oral)
Staphylococci, general properties
-aureus coagulase + and yellow and phage receptor + and protein A +, others - and white and phage receptor - and protein A -
-catalase positive, strep isn't
-facultative Gm+ cocci anaerobes
Staphylococcus aureus, bacteriology, epidemiology,
-Gm+, coagulase+
-often infects via foreign bodies (dialysis catheters or IV catheters)
Staphylococcus aureus, pathogenesis, treatment, prevention
-toxin-mediated
-TSS
-synthesizes adhesive molecules that bind host's cellular matrix
-bacteria will colonize, evade host response, syntehsize toxins and enzymes to lyse host tissues, and then spread
-toxins and enzymes responsible for cell lysis: alpha toxin, leukocidins, proteases, coagulase, staphylokinase, hyaluronidase, lipase
-protein A blunts host immune responses by binding IgG Fc
-protein A, enterotoxins A-E, G, H, and I are superantigens, blunting immune effects
-capsular polysaccharides are anti-phagocytic
-Eap (Map), surface protein that impairs neutrophil recruitment
-consequence: localized abscess and not disseminated, or if not contained, invasion into bloodstream
Staphylococcus aureus, clinical symptoms
-Toxin-mediated diseases: many lead to TSS
-Enterotoxins A-E, G, H, and I are superantigens
-Enterotoxin F is TSST-1, same
-these superantigens lead to massive IL-1, IL-2, TNF, inflammation, and TSS
-staph scalded skin syndrome (SSSS) caused by exfoliatins A and B (EtaA and EtaB)
-Invasive diseases characterized by suppuration and abscess formation: impetigo, folliculitis, furuncles, carbuncles, cellulitis, lymphangitis, cather site infections, paronychia, mastitis, penumonia, endocarditis, osteomyelitis, arthirits, abscess, meningitis, sepsis
Staphylococcus aureus, treatment, prevention
Tx: abscess need to be drained, semisynthetic penicillin, vancomycin
Prevention: hand washing, etc
Staphylococcus epidermis
-coagulase-, Gm+ white colonies, catalase+
-sensitive to novobiocin
-foreign bodies
-colonize prosthetic surfaces very efficiently
-forms biofilms
-low grade fever, possible bacteremia, treatment with vancomycin with rifampin and/or gentamicin
Staphylococcus saprophyticus
-G+ cocci, coagulase-, catalase+, resistant to novobiocin
-urinary tract infection with polyuria and dysuria
-Tx: trimethoprim sulfamethoxazol
-norfloxacin (quinolone)
Streptococcus pyogenes, general properties
-Gm+ cocci, anaerobes, aerotolerant, catalse-
-Gamma-hemolysis
-Alpha-hemolysis (green zone, partial)
-Beta-hemolysis (complete, further categorized as Group A, B, C, N, O for C-carbohydrate on cell wall; A further categorized as 1-80 for M-protein)
Group A beta hemolytic streptococcus pyogenes, acute diseases
-puerperal fever
-acute pharyngitis and tonsilitis (strep-throat)
-scarlet fever (caused by exotoxin, speA spe B speC acting as superantigens)
-these superantigens can lead to TSS
-necrotizing faciitis
Streptococcus pyogenes, pathogenesis
-streptolysins A and O, O is oxygen-labile
-streptolysins lyse or injure other cells
-streptokinase, DNAase
-hyaluronic acid capsule (anti-phagocytotic)
-M-proteins
Streptococcus pyogenes group A beta hemolytic, sequelae of infection
-rheumatic fever: 2-3 weeks after strep infection, caused by anti-M-protein abs that x-rct with antigens present in heart and joints
-strep group a beta hemolytic
-acute glomerulonephritis from deposition of immune complexes
Streptococcus pyogenes, diagnosis, treatment
-Beta hemolysis on blood agar plates
-sensitivity to bacitracin, correlates with group A
-agglutination test with tiny plsatic beads coated with anti-group A strep ab
-ELISA
-high titer of ab to streptolysin O (the ASO titer)
-Tx, all streptococcus pyogenes are sensitive to penicillin
Streptococci agalactiae
-group B beta-hemolytic streptococcus
-neonatal infections
Enterococcus faecalis
-group D beta-hemolytic streptococcus
-urinary tract infections
Viridans streptococci
-alpha-hemolytic streptococcus
-universal inhabitants of mouth, nose, pharynx
-most frequent cause of infective endocarditis
Streptococcus pneumoniae (pneumococcus), general properties
-Gm+ diplococci, short dimension apposed (Neisseria: long dimension apposed)
-alpha-hemolytic
-optochin sensitive, while alpha-hemolytic streptococci are resistant)
-Quellung reaction: specific antibody to capsule well swell it, nearly 100 types of serotypically distinct capsules
Streptococcus pneumoniae, pathogenesis, Dx, Tx
-most frequent form of bacterial pneumonia
-Dx: microscopic
-Tx: multiple antibiotic resistance
-prevention: penumococcal vaccine: pneumovaxTM: t-cell independent, 17 serotypes of capsular polysaccharide; or prevnarTM: 7 pneumococcal types and highly immunogenic protein, t-cell dependent
Listeria monocytogenes
-beta-hemolytic
-Gm+ rod
-wide-spread, grows well at refrigerator temperature
-transplacental and can lead to abortion and stillbirth
-facultative intracellular bacterium
-can cross placenta via its mechanism of using actin to propel itself from one cell to the next
Anthrax (bacillus antracis)
-aerobic Gm+ spore-forming rod
-cutaneous anthrax (by spores), intestinal anthrax (rare), inhalation anthrax (by spores)
-anthrax is zoonotic
Spirochetes, general properties
-elongated, flexible, and motile
-twisted spirally
-binary fission, Gm- type of structure
-Genus: Treponema (syphilis, yaws, pinta), Borrelia (relapsing fever and Lyme Disease), Leptospira (leptospirosis)
Treponema pallidum, general properties
-agent of human syphilis
-made visible by darkfield, immunofluoresence, deposition of silver salts on bacterial surface, or e- microscophy
-cannot be cultured
-will survive in blood/tissue specimens for 24 hours
-easily killed, but storable at -80C for years
-can be cultured in testicular tissue of rabbits
-congenital herpes
-usually venereal
Treponema pallidum, pathogenesis
-incubation, primary lesion (chancre), secondary lesions (organsim has disseminated), tertiary lesions (many years after initial infection) damage due to hypersensitivity
Treponema pallidum, modern diagnostic tests, treatment
-non-specific: VDRL (veneral disease research laboratory) test; a flocculation test with cardiolopin
-specific: FTA-ABS (fluorescent treponenal antibody-absorption), micro-hemagglutination test, ELISA, TPI (trep pallidum immobilization test)
-PCR NOT USED
-sensitive to penicillin, resistance not found!
Treponema pallidum, other treponemal diseases
-yaws: T. pertenue
-non-venereal, through open sores
-bejel: T. pallidum subspeces endemicum
-pinta: T. carateum, heals spontaneously, leaving pigmented areas
Borrelia, relapsing fever
-B. hernsii endemic in western US, transmitted by ticks to rodents, and then to man (rodents are reservoir)
-B. recurrentis is epidemic, human to human via body louse
-fever 4-5 days, afebrile for 7-10, then recurs and disappears (3-10 relapses)
-relapse occurs from antigenic variation of surface proteins encoded on a LINEAR PLASMID
Borrelia, Lyme Disease
-Borrelia burgdorferi
-most common tick-borne disease in US
-endemic on east coast and Pacific NW
-White-tailed deer and white-footed moose are the major reservoirs
-first: papule with expanding erythema, second: various neurological and cardiac involvements, third: migrating episodes of arthritis
Dx: bright red rash, ELISA, chronic arthritis (3-5 yrs into disease)
Tx: Tetracylcine or ampicillin
Vx: surface protein A vaccine
UNIQUE: Iron NON-requirement
Leptospira
-a spirochete
-not arthropod borne
-leptospirosis
-transmitted by animals often via urine
-enters blood invades various tissues
-muscular pain, headache, photophobia, fever, chills
-
Mycoplasma, general properties
-smallest organism able to grow and reproduce autonomously
-pleomorphic, no cell wall (can't use penicillin class)
-fried egg appearance
-only bacterial membrane to contain cholesterol
-variable lipoproteins (VLP) help stabilize structure and provides immune diversity
Mycoplasma pneumoniae
-has protein P1 complex that promotes its attachment to host cells
-spotty points of infection, not lobar (atypical pneumonia)
-gliding motility
-produces hydrogen peroxide and superoxide
-inflammation
-Dx: complement fixation test
-Tx: erythromycin
Vibrio cholerae
-Gm- motile, comma shaped, polar flagellum
-O, H, endotoxin, enterotoxin (cholera toxin)
-major colonization factor (toxin coregulated pilus)
-cholera toxin binds to GM1 gangliosides of endothelial cells
-enters cell
-stimulates cAMP production, MASSIVE FLUID LOSS
-Tx: ORT oral rehydration therapy
Campylobacter species
-curved comma-shaped microaerophilic Gm- rods in animal species
-zoonotic disease (half of raw chicken has Campylobacter)
-1/1000 infected will develop autoimmunity to their own nerves
Yersinia pestis
-large rod-shaped or coccobacillary Gm-
-anti-phagocytic capsule (F1 antigen)
-other anti-phagocytic ppts (V, W antigens)
-anti-phagocytic properties present at 37 not 28 (flea temperature)
-transmission flea to mammal (bubonic) or mammal to mammal (primary pneumonic)
Franciscella tularensis
-cause of tularemia
-unencapsulated pleomorphic Gm-
-zoonotic disease from arthropods (ticks, flies, etc) and rbabit
-fever, chills, malaise
-ulceroglandular (skin ulcer and painful adenopathy)
Dx: serologic, fluorescent, dangerous to culture (lab incidents)
Tx: streptomycin
Prevention: vaccine (live attenuated)
Brucella
Pleomorphic fastidious Gm-, grows slowly, requires 10% CO2 for optimal growth
-disease of reticuloendothelial system in humans
-organisms ingested by PMN, multiply in monocytes, form granulomas
-cattle, swine, goats, sheep, etc