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59 Cards in this Set
- Front
- Back
Clostridium, general properties
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Obligate anaerobic
Gm+ rods Spore forming Catalase/ oxidase negative Toxin producing |
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Clostridium botulinum, food botulism
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-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 |
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Clostridum tetani
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-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) |
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Clostridum difficile
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-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 |
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Clostridum perfringens
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-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 |
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Clostridum toxins
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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 |
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Clostridium botulinum, subsets
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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 |
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Anaerobes, overview
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Gm+ rods: Proprionibacterium, antinomyces
Gm- rods: Bacteroides, fusobacterium, prevotella, porphyromonas Gm+ cocci: Peptostreptococcus Spores: Clostridium |
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Anaerobes, antibiotics
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Penicillin except against Bacteroides fragilis
-use penicillin for anaerobes above the diaphragm -clindamycin and cefoxitin against B. fragilis |
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Eikenella corrodens
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Penicllin sensitive, aerobic Gm- rod causing human bite infections
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Actinomyces
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-Gm+ rods
-sulfur granules -oral, facial, pharynx, GI |
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Streptococcus viridans
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-oral flora
-Gm+ cocci, gamma-hemolytic -cause of dental plaques -most common cause of subacute endocarditis |
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Diphtheroids
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-oral flora
-Gm+ rods |
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Fusobacterium
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-needle-like Gm- rods
-penicillin sensitive -obligate anaerobe, very -oral flora |
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Prevotella melaninogenicus
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-Gm- rods
-very sensitive to oxygen -requires hemin -produces black pigment on blood agar plates -penicillin sensitive -oral infections |
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Porphyromonas (gingivalis)
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-Gm- rods
-uses hemin -brown/black pigment on blood agar plate -penicillin sensitive -cause of gingivitis |
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Peptostreptococcus
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-Gm+ cocci
-flora in mouth, GI, and urogenital tracts |
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B. fragilis
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-anaerobic Gm- rod
-oxygen tolerant -below the diaphragm -penicillin resistant |
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Bifidobacterium
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-anaerobic Gm+ rods
-flora of GI -sensitive to penicillin -generally not pathogenic |
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Lactobacillus
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-anaerobic Gm+ rods
-non-pathogen -maintains an acidic pH in the colon -flora of GI |
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Flora, respiratory tract
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-Eikenella corrodens (thoat)
-Staph aureus (nose) |
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Flora, female genitourinary tract
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-fecal flora
-lactobacillus -Group B strep |
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Flora, skin
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Staph epidermidis
Staph aureus Diphteroids Proprionibacterium (acnes species implicated in acne) Peptococcus |
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Flora, GI
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-bacteroides
-bifidobacterium -lactobacilli -clostridium -coliforms -enterococcus -remember abnormal bacterial overgrowth may convert conjugated bile acid to free bile acid, causing fat malabsorption |
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Flora, oral
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-Staph epidermidis (oral)
-Neisseria (oral) -Strep viridans (oral) -Fusobacterium (oral) -Prevotella (oral) Peptostreptococcus (oral) |
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Staphylococci, general properties
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-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 |
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Staphylococcus aureus, bacteriology, epidemiology,
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-Gm+, coagulase+
-often infects via foreign bodies (dialysis catheters or IV catheters) |
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Staphylococcus aureus, pathogenesis, treatment, prevention
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-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 |
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Staphylococcus aureus, clinical symptoms
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-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 |
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Staphylococcus aureus, treatment, prevention
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Tx: abscess need to be drained, semisynthetic penicillin, vancomycin
Prevention: hand washing, etc |
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Staphylococcus epidermis
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-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 |
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Staphylococcus saprophyticus
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-G+ cocci, coagulase-, catalase+, resistant to novobiocin
-urinary tract infection with polyuria and dysuria -Tx: trimethoprim sulfamethoxazol -norfloxacin (quinolone) |
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Streptococcus pyogenes, general properties
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-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) |
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Group A beta hemolytic streptococcus pyogenes, acute diseases
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-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 |
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Streptococcus pyogenes, pathogenesis
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-streptolysins A and O, O is oxygen-labile
-streptolysins lyse or injure other cells -streptokinase, DNAase -hyaluronic acid capsule (anti-phagocytotic) -M-proteins |
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Streptococcus pyogenes group A beta hemolytic, sequelae of infection
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-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 |
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Streptococcus pyogenes, diagnosis, treatment
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-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 |
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Streptococci agalactiae
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-group B beta-hemolytic streptococcus
-neonatal infections |
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Enterococcus faecalis
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-group D beta-hemolytic streptococcus
-urinary tract infections |
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Viridans streptococci
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-alpha-hemolytic streptococcus
-universal inhabitants of mouth, nose, pharynx -most frequent cause of infective endocarditis |
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Streptococcus pneumoniae (pneumococcus), general properties
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-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 |
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Streptococcus pneumoniae, pathogenesis, Dx, Tx
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-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 |
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Listeria monocytogenes
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-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 |
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Anthrax (bacillus antracis)
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-aerobic Gm+ spore-forming rod
-cutaneous anthrax (by spores), intestinal anthrax (rare), inhalation anthrax (by spores) -anthrax is zoonotic |
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Spirochetes, general properties
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-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) |
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Treponema pallidum, general properties
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-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 |
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Treponema pallidum, pathogenesis
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-incubation, primary lesion (chancre), secondary lesions (organsim has disseminated), tertiary lesions (many years after initial infection) damage due to hypersensitivity
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Treponema pallidum, modern diagnostic tests, treatment
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-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! |
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Treponema pallidum, other treponemal diseases
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-yaws: T. pertenue
-non-venereal, through open sores -bejel: T. pallidum subspeces endemicum -pinta: T. carateum, heals spontaneously, leaving pigmented areas |
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Borrelia, relapsing fever
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-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 |
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Borrelia, Lyme Disease
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-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 |
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Leptospira
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-a spirochete
-not arthropod borne -leptospirosis -transmitted by animals often via urine -enters blood invades various tissues -muscular pain, headache, photophobia, fever, chills - |
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Mycoplasma, general properties
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-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 |
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Mycoplasma pneumoniae
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-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 |
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Vibrio cholerae
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-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 |
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Campylobacter species
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-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 |
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Yersinia pestis
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-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) |
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Franciscella tularensis
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-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) |
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Brucella
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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 |