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Bacterial Organisms – Flashcards

Gracie Stone
7 July 2022

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question
  • Gram positive cocci in clusters
  • Catalase positive
  • Facultative anaerobe
  • Ferments mannitol
  • DNase positive
  • Beta-hemolytic
  • Coagulase positive
  • One of the most important human pathogens
  • Causes Scalded Skin Syndrome and Toxic Shock Syndrome
  • Contains the exotoxins coagulase, fibrinolysin, lipase
  • Strains can be resistant to methicillin and vancomycin
  • Grows on PEA, Columbia CNA, and chocolate agar
answer
Staphylococcus aureus
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  • Gram positive cocci in clusters
  • Catalase positive
  • Coagulase negative
  • Does not ferment mannitol
  • DNase negative
  • Normal flora of skin and mucous membranes
  • Opportunistic pathogen; causes prosthetic valve endocarditis, urinary tract infections, wound infections
  • Gamma-hemolytic
  • Susceptible to novobiocin
  • Virulence factor is "slime"
  • Grows on blood, PEA, Columbia CNA, and chocolate agar
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Staphylococcus epidermidis
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  • Gram positive cocci in clusters
  • Found on skin and mucosal membranes of the genitoruinary tract
  • Common cause of urinary tract infections in young, sexually active females
  • Coagulase negative
  • DNase negative
  • Resistant to novobiocin
  • Grows on PEA, Columbia CNA, and chocolate agar
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Staphylococcus saprophyticus
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  • Gram positive cocci in pairs or chains
  • Catalase negative
  • Beta-hemolytic
  • Susceptible to bacitracin
  • Causes bacterial pharyngitis, rheumatic heart disease, acute rheumatic fever, pyoderma, necrotizing fasciitis
  • PYR positive
  • Contains streptolysins O and S, erythrogenic toxin, streptokinase, hyaluronidase
  • Bile esculin negative
  • Hippurate negative
  • A throat swab is used to collect a specimen
  • Catgorized as Lancefield A
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Streptococcus pyogenes (Group A)
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  • Gram positive cocci in pairs or chains
  • Catalase negative
  • Beta- or gamma-hemolytic
  • CAMP factor positive
  • Bacitracin resistant
  • Bile esculin negative
  • May be carried as normal flora in vaginal and gastrointestinal tract
  • Pregnant women should be screened for this bacteria
  • Major cause of neonatal meningitis and sepsis
  • Shows "arrowhead" hemolysis when grown on blood agar with beta-hemolytic S. aureus
  • PYR negative
  • Classified as Lancefield B
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Streptococcus agalactiae (Group B)
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  • Gram positive cocci in pairs that are lancet-shaped and arrange in chains
  • Requires 5-10% carbon dioxide on blood agar
  • Alpha-hemolytic
  • In 24 hr, mucoid colonies with a capsule
  • Susceptible to optochin
  • Causes community acquired pheumonia
  • Transmitted through respiratory droplets
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Streptococcus pneumoniae
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  • Gram positive cocci in pairs or chains
  • Alpha-hemolytic
  • Resistant to optochin
  • Bile resistant
  • Catalase negative
  • Normal flora of human oropharynx, gastrointestinal, and female genital tract
  • Causes subacute bacterial endocarditis
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Viridans streptococcus
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  • Gram positive cocci in pairs or chains
  • Catalase negative
  • Alpha- or gamma-hemolytic on blood agar
  • Bile esculin positive
  • PYR negative
  • Unable to grow in 6.5% NaCl broth
  • Susceptible to penicillin
  • Possess Lancefield Group D antigen
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Streptococcus bovis
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  • Gram positive cocci in pairs or chains
  • Catalase negative
  • Alpha- or gamma-hemolytic
  • Bile esculin positive
  • Grows in 6.5% NaCl broth
  • PYRase positive
  • Penicillin resistant
  • 80-90% of human infections are caused by this species
  • Normal flora of gastrointestinal and genitoruinary tract, on the skin, and in oral cavity
  • May cause urinary tract infections, intra-abdominal abscesses, endocarditis
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Enterococcus faecalis
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  • Gram positive cocci in pairs or chains
  • Catalase negative
  • Alpha- or gamma-hemolytic
  • Bile esculin positive
  • Grow in 6.5% NaCl broth
  • PYRase positive
  • Penicillin resistant
  • Normal flora of the gastrointestinal and genitourinary tract, on the skin, and in oral cavity
  • May cause urinary tract infections, intra-abdominal abscesses, endocarditis
  • Causes 5-10% of human infections
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Enterococcus faecium
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  • Gram negative diplococci with flattened adjacent sides (kidney or coffee bean shape)
  • May resist decolorization
  • Oxidase positive
  • Catalase positive
  • Grows on chocolate agar, Modified Thayer-Martin, Martin-Lewis, New York City, and JEMBEC medium
  • Significant pathogen of urogenital tract
  • Dacron or rayon fibers are used to collect a specimen
  • Requires growth in 3-5% carbon dioxide
  • Utilizes glucose
  • Endocervical specimens are collected from females
  • Small, grayish white, convex, translucent, shiny colonies with either smooth or irregular margins on chocolate agar
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Neiserria gonorrhoeae
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  • Gram negative diplococci with "kidney or coffee bean" shape
  • Catalase positive
  • Oxidase positive
  • Utilizes glucose and maltose
  • Normal flora of upper respiratory tract, but can cause meningococcemia, septic shock  with hemorrhage in the adrenal glands, and bacterial meningitis
  • Infection is spread in college dorms and miltary bases
  • Medium, smooth, round, moist, gray to white colonies on chocolate agar
  • Can grow on Thayer-Martin, modified Thayer-Martin, and Martin-Lewis agar
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Neiserria meningitidis
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  • Gram negative diplococci with "kidney or coffee bean" shape
  • Can resist decolorization and appear as gram positive cocci in pairs, tetrads, and small clusters
  • Oxidase positive
  • DNase positive
  • Cannot utilize carbohydrates
  • Normal commensal of respiratory tract
  • Causes upper respratory tract infections in healthy children and the elderly
  • Large, nonpigmented or gray, "hockey puck" colonies on chocolate agar
  • Clinicall significant when bacteria are accompanied with polymorphonuclear neutrophils
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Moraxella catarrhalis
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  • Gram negative bacilli
  • Catalase negative
  • Gamma-hemolytic
  • Oxidase negative
  • IMViC (indole, methyl red, VP, citrate): + + - -
  • Lysine positive
  • ONPG positive
  • TSI (triple sugar): A/A, H2S negative
  • Yellow colonies on Hektoen Enteric/ XLD agar
  • Pink colonies on MacConkey agar
  • Resistant to penicillins, erythromycin, clindamycin, vancomycin, and ampicillin
  • Causes urinary tract infections, meningitis, Traveler's Diarrhea, dysentery
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Escherichia coli
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  • Gram negative coccobacilli
  • Catalase positive
  • ONPG negative
  • Reduces nitrate to nitrite
  • TSI: K/A, H2S positive
  • IMViC: - + - +
  • Lysine positive
  • Positive motility
  • PYR negative
  • Contains O, H, and Vi antigens
  • Urease negative
  • Gamma-hemolytic
  • Red colonies with black centers on XLD agar
  • Clear colonies on MacConkey agar
  • Causes gastroenteritis and enterocolitis and typhoid fever
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Salmonella typhimurium
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  • Gram negative coccobacilli
  • Catalase positive
  • Oxidase negative
  • TSI: K/A, H2S negative
  • IMViC: V + - -
  • ONPG negative
  • Negative motility
  • Urea negative
  • Gamma-hemolytic
  • Clear colonies on MacConkey agar
  • Green colonies on Hektoen enteric agar
  • Causes bacillary dysentery
  • Contains antigen B
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Shigella flexneri
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  • Gram negative coccobacilli
  • Catalase positive
  • Oxidase negative
  • ODC positive
  • ONPG positive
  • IMViC: V + - -
  • TSI: K/A, H2S negative
  • Negative motility
  • Ornithine decarboxylase positive
  • Gamma-hemolytic
  • Urea negative
  • Smooth, round, bud-like colonies
  • Contains antigen D
  • Causes bacillary dysentery
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Shigella sonnei
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  • Gram negative coccobacilli
  • Oxidase negative
  • IMViC: + + - -
  • TSI: K/A, H2S positive
  • Urea negative
  • Positive motility
  • ONPG negative
  • Most positive for lysin
  • Ferments glucose with gas production
  • Phenylalanine deaminase negative
  • Gamma-hemolytic
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Edwardsiella
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  • Gram negative coccobacilli
  • Oxidase negative
  • IMViC: - + - -
  • Nonmotile at 37 degrees Celsius
  • Urea negative
  • Ferments glucose
  • Reduces nitrate to nitrite
  • Gamma-hemolytic
  • Facultative anerobe
  • Primarily a disease of rodents
  • Agent of black plague
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Yersinia pestis
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  • Gram negative coccobacilli
  • Oxidase negative
  • IMViC: V + - -
  • Urea positive
  • Nonmotile at 37 degrees Celsius
  • "Bull's eye" colonies on CIN agar after 48 hrs.
  • Gamma-hemolytic
  • Can survive cold temperatures
  • Can mimic appendicitus and cause acute enteritis
  • Found in contaminated pork
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Yersinia enterocolitica
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  • Gram negative coccobacilli
  • Oxidase negative
  • Reduces nitrate to nitrite
  • IMViC: - + - -
  • Urea positive
  • Nonmotile at 37 degrees Celsius
  • Gamma-hemolytic
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Yersinia pseudotuberculosis
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  • Gram negative coccobacilli
  • Catalase negative
  • TSI: A/A, H2S negative
  • IMViC: - - + +
  • Negative motility
  • Lysine positive
  • ONPG positive
  • PAD negative
  • Arginine negative
  • Gamma-hemolytic
  • Pink colonies on MacConkey agar
  • Yellow colonies on Hektoen enteric/ XLD agar
  • Causes pneumonia and urinary tract infections
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Klebsiella pneumoniae
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  • Gram negative coccobacilli
  • Catalase positive
  • Oxidase negative
  • IMViC: - - + +
  • TSI: A/A, H2S negative
  • Lysine positive
  • Arginine negative
  • Urea negative
  • Reduces nitrate to nitrite
  • Gamma-hemolytic
  • Slightly mucoid, grey-white colonies
  • Pink colonies on MacConkey agar
  • Yellow colonies on Hektoen enteric/ XLD agar
  • Causes meningitis and urinary and respiratory infections
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Enterobacter aerogenes
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  • Gram negative coccobacilli
  • Catalase positive
  • Oxidase negative
  • IMViC: - - + +
  • TSI: A/A, H2S negative
  • Reduces nitrate to nitrite
  • Urea positive
  • Positive motility
  • Pink colonies on MacConkey agar
  • Yellow colonies on Hektoen enteric/ XLD agar
  • Causes urinary tract infections, endocarditis, septic arthritis, respiratory infections
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Enterobacter cloacae
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  • Gram negative coccobacilli
  • Oxidase negative
  • Catalase negative
  • IMViC: - - + +
  • TSI: A/A, H2S negative
  • Positive motility
  • Reduces nitrate to nitrite
  • ONPG positive
  • Lysine positive
  • Ornithine positive
  • Urease negative
  • Lipase negative
  • Gamma-hemolytic
  • Pink colonies on MacConkey agar
  • Colonies show a red pigment
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Serratia marcescens
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  • Gram negative coccobacilli
  • Oxidase negative
  • Catalase positive
  • IMViC: - + V V
  • TSI: K/A, H2S positive
  • ONPG negative
  • Reduces nitrate to nitrite
  • Produces acid from glucose
  • Arginine negative
  • Lysine negative
  • Swarming motility
  • Ornithine positive
  • Gamma-hemolytic
  • Most frequent isolate from clinical specimens
  • Common cause of urinary tract infections and wound infections
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Proteus mirabilus
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  • Gram negative coccobacilli
  • Oxidase negative
  • Catalase positive
  • IMViC: + + - -
  • TSI: A/A, H2S positive
  • Ornithine negative
  • Urea negative
  • Lysine negative
  • Arginine negative
  • ONPG negative
  • Gamma-hemolytic
  • Swarming motility
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Proteus vulgaris
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  • Gram negative coccobacilli
  • Oxidase negative
  • TSI: K/A, H2S negative
  • Negative motility
  • PAD positive
  • Urea positive
  • Reduces nitrate to nitrite
  • Gamma-hemolytic
  • Clear or pale pink colonies on MacConkey agar
  • Yellow or colorless colonies on Hektoen enteric/ XLD agar
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Providencia
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  • Gram negative coccobacilli
  • Oxidase negative
  • IMViC: + + - -
  • TSI: K/A, H2S negative
  • Urea positive
  • Negative motility
  • PAD positive
  • Ornithine positive
  • Gamma-hemolytic
  • Clear or pale pink colonies on MacConkey agar
  • Colorless or red colonies on Hektoen enteric/ XLD agar
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Morganella
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  • Gram negative coccobacilli surrounded by flagella
  • Catalase positive
  • Oxidase negative
  • IMViC: - + - +
  • TSI: K/A and A/A, H2S positive
  • ONPG positive
  • Lysine negative
  • Ferments glucose, lactose, maltose, and sucrose
  • Low convex, gray, medium sized, translucent to opaque colonies with glossy surfaces
  • Normal flora of gastrointestinal tract
  • Causes urinary and respiratory tract infections, gastroenteritis
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Citrobacter freundii
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  • Gram negative coccobacilli
  • Oxidase negative
  • Positive motility
  • Indole negative
  • Urease negative
  • VP positive
  • Lysine positive
  • ONPG positive
  • Ferments glucose with gas production
  • Gamma-hemolytic
  • Reduces nitrate to nitrite
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Hafnia
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  • Gram negative coccobacilli
  • Oxidase positive
  • Ferments glucose and inositol but not lactose or sucrose
  • Gamma-hemolytic
  • Reduces nitrate to nitrite
  • Motile by a polar flagella
  • Shiny, opaque colonies
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Plesiomonas
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  • Long, thin gram negative bacilli
  • Oxidase positive
  • Utilizes glucose, fructose, and xylose but not lactose or sucrose
  • Single polar flagellum
  • May be encapsulated
  • Aerobic but can grow without oxygen if nitrate is available as a respiratory electron acceptor
  • Aluminum foil or metallic sheen
  • Sweet, fruity odor
  • Characteristic of cystic fibrosis patients
  • Fluoresces under UV light
  • Rough, spreading colonies with ground glass appearance and serrated or jagged edges
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Pseudomonas aeruginosa
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  • Gram negative bacilli
  • Catalase positive
  • Oxidase positive
  • Nonproteolytic
  • Gelatin negative
  • Positive motility
  • Arginine positive
  • Yellow fluorescent colonies
  • Causes urinary tract and wound infections
  • Cannot grow above 35 degrees Celsius
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Pseudomonas putida
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  • Gram negative bacilli
  • Catalase positive
  • Oxidase positive
  • DNase negative
  • Utilizes glucose and mannitol
  • Medium to large, mucoid, smooth, white colonies on blood agar
  • Mostly causes plant infections and food spoilage
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Pseudomonas fluorescens
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  • Gram negative bacilli
  • Weak positive catalase test
  • Positive motility
  • DNase negative
  • Lysine positive
  • Oxidizes glucose, maltose, lactose, and mannitol
  • Lactose negative
  • Resistant to aminoglycosides
  • Smooth and slightly raised yellow or green colonies on blood agar with a "dirt-like" odor
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Burkholderia cepacia
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  • Gram negative bacilli
  • Oxidase positive
  • Positive motility
  • Oxidizes lactose
  • Arginine positive
  • Resistant to colistin and polymyxin B
  • Nonlactose fermentor on MacConkey agar, but can appear pink after 4-7 days
  • Musty or earthy odor
  • Smooth and mucoid or dry and wrinkled colonies on blood agar
  • Etiologic agent of melioidosis
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Burkholderia pseudomallei
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  • Pleomorphic, aerobic gram negative bacilli
  • Appears as coccobacillus in singles, pairs, and short chains
  • Can resemble as gram positive cocci when grown in liquid medium or direct Gram stains
  • Oxidase negative
  • Nonmotile
  • Gamma-hemolytic
  • Nonlactose fermenter
  • Gelatin and lysine negative
  • Called "Iraqibacter"
  • Nosocomial pathogen; causes severe pneumonia and bloodstream and urinary tract infections
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Acinetobacter baumannii
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  • Gram negative bacilli
  • Oxidase negative
  • Catalase positive
  • Weakly oxidizes maltose and glucose
  • DNase positive
  • ONPG positive
  • Arginine negative
  • Ornithine negative
  • Decarboxylates lysine
  • Causes pneumonia and cystic fibrosis, urinary tract infections through Foley catheters, bloodstream infections through intravenous lines
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Stenotrophomonas maltophilia
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  • Gram negative bacilli
  • Oxidase negative
  • Positive motility
  • Nitrate positive but nitrite negative
  • Asaccharolytic
  • "Green apple" odor
  • Thin, spreading colony with irregular edges on blood agar; can produce green discoloration
  • Opportunistic pathogen
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Alcaligenes faecalis
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  • Gram negative bacilli
  • Catalase negative
  • Oxidase positive
  • Oxidizes glucose and xylose
  • Reduces nitrate to nitrite
  • Causes cirrhosis, bacteriemia, meningitis, pneumonia, peritonitis
  • White, smooth, round colonies on blood agar
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Achromobacter
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  • Gram negative bacilli
  • Catalase positive
  • Oxidase positive
  • PDA positive
  • Utilizes glucose, lactose, and sucrose
  • Positive motility
  • Causes urinary tract infections and urosepsis
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Oligella
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  • Gram negative bacilli
  • Polar, sheatheed flagella when grown in broth, but have peritrichous unsheathed flagella when grown on solid media
  • Oxidase positive
  • Facultative anaerobe
  • Urease negative
  • Citrate positive
  • Indole positive
  • Causative agent of cholera or epidemia cholera
  • Must grow on thiosulfate citrate bile salts (TCBS) sucrose agar and other enrichment media
  • Incubation period is 8-48 hrs.
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Vibrio cholerae
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  • Gram negative, straight, comma-shaped, or curved bacilli with a single polar flagellum
  • Catalase positive
  • Sucrose negative
  • Gamma-hemolytic
  • LDC positive
  • ADH negative
  • Requires growing in increased CO2 and salt environment
  • Found in shrimp, oysters, crabs
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Vibrio parahaemolyticus
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  • Gram negative straight, comma-shaped, or curved bacilli with a single polar flagellum
  • Catalase positive
  • LDC positive
  • ADH negative
  • Sucrose negative
  • Grow in increased CO2 and salt environment
  • Found in shrimp, oysters, and crabs
  • Causes gastroenteritis, wound infections, septicemia
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Vibrio vulnificus
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  • Gram negative straight, comma-shaped, or curved bacilli with a single polar flagellum
  • Catalase positive
  • Sucrose negative
  • VP negative
  • Found in shrimp, oysters, and crabs
  • Grow in increased CO2 and salt environment
  • Causes gastroenteritis, wound infections, septicemia
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Vibrio mimicus
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  • Gram negative straight, comma-shaped, or curved bacilli with a single polar flagellum
  • Catalase positive
  • Sucrose positive
  • VP positive
  • LDC positive
  • ADH negative
  • Found in shrimp, oysters, and crabs
  • Grow in increased CO2 and salt environment
  • Causes gastroenteritis, wound infections, and septicemia
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Vibrio anginolyticus
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  • Gram negative bacilli with spirals and seagull wings
  • Catalase positive
  • Oxidase positive
  • Hippurate negative
  • H2S positive
  • CAMPY-BAP is used to isolate this species
  • Must grow in microaerophilic and capnophilic environment with gas mixture of approximately 85% N and 5-10% O2 and 10% CO2
  • Incubation is at 42 degrees Celsius
  • Causes Guillain-Barre
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Camplyobacter
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  • Small gram negative bacilli
  • Catalase positive
  • Oxidase positive
  • Xylose positive
  • ALA negative
  • Reduces nitrates
  • Requires both factors X and V
  • Gamma-hemolytic
  • Most important virulence factor is capsule
  • Most common cause of bacterial otitis media and acute sinusitis
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Haemophilus influenzae
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  • Small gram negative coccobacilli
  • Catalase positive
  • Oxidase positive
  • Xylose negative
  • ALA negative
  • Requires both factors X and V to grow
  • Gamma-hemolytic
  • Causes meningitis in children
  • Likes to grow around S. aureus
  • Needs moisture to grow
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Haemophilus influenzae aegyptius
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  • Tiny gram negative bacilli resembling "school of fish"
  • Catalase positive
  • Oxidase positive
  • ALA negative
  • Gamma-hemolytic
  • Cannot utilize glucose, sucrose, lactose, and fructose
  • Requires X factor to grow
  • Causes chancroid, a venereal disease
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Haemophilus ducreyi
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  • Gram negative bacilli
  • Catalase positive
  • Oxidase negative
  • Ferments glucose
  • Urease negative
  • Requires chocolate agar with IsoVitale XTM or charcoal-yeast agar to grow
  • Agent of tularemia
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Francisella tularensis
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  • Gram negative coccobacilli
  • Catalase positive
  • Oxidase positive
  • Flat, wet colonies on sheep blood and chocolate agars
  • Transmitted through bites, scratches, and licking of skin breaks by dogs, cats, and other animals
  • Contains endotoxin, capsule, hemagglutins, and cytotoxins as virulence factors
  • Purulent material or tissue from bite wound are usually examined
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Pasteurella
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  • Gram negative bacilli
  • Nonmotile
  • Strict aerobe
  • Smooth, mucoid, convex colonies resembling "mercury drops" with a pearly luster on Bordet-Gengou medium with 20% blood with diffuse zone of hemolysis after 7 days
  • Requires 3-7 days incubation in moist container
  • Best cultured on charcoal-containing medium and Bordet-Gengou medium with 20% blood
  • Causes whooping cough
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Bordetella pertussis
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  • Gram negative bacilli
  • Catalase positive
  • Oxidase positive
  • Urease positive
  • Smooth, raised, and translucent colonies
  • Facultative intracellular pathogens that can reside within phagocytic cells
  • Spread through ingestion of unpasteurized milk
  • Causes undulant fever
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Brucella
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  • Gram negative bacilli
  • Catalase negative
  • Indole negative
  • Nitrate positive
  • Requires an increased CO2 (5-10%) environment
  • Usual flora of oral cavity
  • Significant cause of endocarditis
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Aggregatibacter (Haemophilus) aphrophilus
question
  • Gram negative bacilli
  • Catalase negative
  • Oxidase positive
  • Indole positive
  • Nitrate negative
  • Negative motility
  • Star-shaped centered colonies on blood agar
  • Require an increased CO2 (5-10%) environment
  • Will not grow on MacConkey agar
  • Usual flora of oral cavity
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Aggregatibacter (Actinobacillus) actinomycetemcomitans
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  • Gram negative bacilli with bulbous (swollen) ends
  • Catalase negative
  • Oxidase positive
  • Indole positive
  • Urease negative
  • Nitrate negative
  • Glucose, sucrose, and mannitol positive
  • Requires increased CO2 (5-10%) environment
  • Cannot grow on MacConkey agar
  • Causes endocarditis
  • Usual flora of oral cavity
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Cardiobacterium hominis
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  • Gram negative bacilli
  • Oxidase positive
  • Catalase negative
  • Indole negative
  • Nitrate positive
  • Glucose, mannitol, and sucrose negative
  • Requires an increased CO2 (5-10%) environment
  • Significant cause of endocarditis
  • Usual flora of oral cavity
  • Produces a bleach-like odor
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Eikenella corrodens
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  • Gram negative plump bacilli in chains
  • Oxidase positive
  • Catalase negative
  • Indole negative
  • Nitrate negative
  • Glucose positive
  • Colonies show small but distinct zones of beta-hemolysis
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Kingella
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  • Gram negative filamentous bacilli
  • Catalase negative
  • Oxidase negative
  • Indole negative
  • Urease negative
  • Requires media enriched with whole blood, serum or ascitic fluid
  • Circular, convex, gray, smooth, glistening colonies with a fried egg appearance
  • Normal flora of oropharynx of rodents
  • Causes Rat Bite Fever and Haverhill Fever
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Streptobacillus moniliformis
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  • Gram negative bacilli
  • Catalase positive
  • Oxidase positive
  • Ferments glucose, trehalose, N. acetylglucosamine, and gluconate
  • Cannot ferment L-arabinose, D-galactose or D-maltose
  • Rare cause of human infection
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Chromobacterium violaceum
question
  • Gram negative bacilli
  • Catalase positive
  • Oxidase positive
  • Sucrose negative
  • H2S positive
  • Small, opaque, yellow-pigmented, shiny, nonhemolytic colonies
  • Causes bacteriemia following dog bites
answer
Capnocytophaga
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  • Large, sporeforming gram positive bacilli in chians
  • Gamma-hemolytic
  • Spores viable for up to 50 years
  • Produces acid from glucose, sucrose, and maltose
  • Susceptible to penicillin
  • Negative motility
  • Can grow on Columbia colistin-nalidixic acid (CNA) agar, bicarbonate agar, mannitol-egg yolk-polymyxin (MYP), polymyxin-egg yolk-mannitol bromothymol blue agar
  • Causes anthrax, Wollsorters' disease, adn progressive endophthalmitis
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Bacillus anthracis
question
  • Large, sporeforming gram positive bacilli in chains
  • Beta-hemolytic
  • Positive motility
  • Resistant to penicillin
  • Citrate positive
  • VP positive
  • Gelatin hydrolysis positive
  • Associated with fried rice
  • Causes opportunistic infections of the eye, as well as meningitis, septicemia, and osteomyelitis
  • Causes diarrheal syndrome
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Bacillus cereus
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  • Gram positive bacilli, appearing in pallisades and give "Chinese letter" arrangement
  • Catalase positive
  • Does not produce spores
  • Non-acid fast
  • Ferments glucose, maltose, and sucrose
  • Produces a halo on cysteine-tellurite blood agar and modified Tinsdale (TIN) agar
  • Methlyene blue smear is used to detect granules
  • Produces metachromatic graules ("Babes' Ernst" bodies)
  • Causes diphtheria
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Corynebacterium diphtheriae
question
  • Gram positive bacilli
  • Catalase positive
  • Oxidase positive
  • Lipophilic positive
  • Urease negative
  • Non-acid fast
  • Produces no spores
  • Pinpoint, white colonies on blood agar
  • Causes nosocomial infections and septicemia, skin infections,a nd other infections in immunocompromised hosts
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Corynbacterium jeikeium
question
  • Gram positive non-spore forming coccobacilli
  • Catalase positive
  • Ferments glucose
  • VP positive
  • Esculin  hydrolysis positive
  • "Umbrella" motility at 25 degrees Celsius
  • Produces a "block" type of hemolysis in CAMP test
  • Grows in 6.5% NaCL
  • Patients who are immunocompromised and women who are pregnant should avoid eating soft cheeses
answer
Listeria monocytogenes
question
  • Long and filamentous, non-spore forming gram positive bacilli
  • Also may appear as coccobacillary in chains and palisades and pleomorphic gram positive bacilli
  • Catalase, H2S, motility, esculin, glucose, nitrate, and urease negative
  • Commensal or normal flora in the oral cavity, gastrointestinal tract, and female genital tract
  • Tiny, pinpoint, alpha-hemolytic to large, rough, gray colonies on blood agar
  • Causes bacteriemai, enodcarditis, and pneumonia
answer
Lactobacillus
question
  • Gram positive, non-spore forming, pleomorphic bacilli that may form long filaments, may be arranged singly, in short chains, or in a V shape
  • Catalase negative
  • Produces H2S on TSI agar
  • Can cause disease in animals (swine, turkey, sheep)
  • Humans acquire infection through occupational exposure
answer
Erysipelothrix rhusiopathiae
question
  • Gram positive, non-spore forming, short, pleomorphic bacilli or coccobacilli
  • Catalase and oxidase negative
  • Hippurate hydrolysis positive
  • Beta-hemolytic on human blood agar, but gamma-hemolytic on sheep blood agar
  • Produces small, gray, opaque colonies with diffuse zone of beta-hemolysis
  • Associated with bacterial vaginosis
    • Results in foul-smelling discharge and vaginal pH greater than 4.5
    • Observation of clue cells in wet mounts is helpful
  • Sensitive to metronidazole and ampicillin
answer
Gardnerella vaginalis
question
  • Gram positive bacilli with terminal spores, resembling a tennis racket, lollipop, or drumstick
  • Catalase negative
  • Slightly beta-hemolytic
  • Lipase positive
  • Lecithinase negative
  • Obligate anaerobe
  • Produces powerful neurotoxin that causes constant muscle contraction
  • Grows on egg yolk agar
  • Causes tetanus
answer
Clostridium tetani
question
  • Gram positive bacilli with subterminal spores
  • Catalase negative
  • Lipase positive
  • Obligate anaerobe
  • Exotoxin is detected in serum, stool, and food
  • Grows on egg yolk agar
  • Infants should not eat honey when this bacteria is present
  • Causes infantile botulism after ingestion of spores
answer
Clostridium botulinum
question
  • Large, straight-edged gram positive bacilli in chains
  • Usually unwilling to produce its central or subterminal spore
  • Exhibits double zone of beta-hemolysis
  • Lipase negative
  • Lecithinase positive
  • Indole negative
  • DNase positive
  • Positive motility
  • Black colonies with 2-4mm opaque white zone on egg yolk agar
  • Causes gas gangrene,m myonecrosis, pleuropulmonary infections, and post-abortion sepsis
answer
Clostridium perfringens
question
  • Gram positive bacilli with subterminal spores
  • Catalase negative
  • Lecithinase negative
  • Ferments glucose and fructose
  • Poistive motility
  • Obligate anaerobe
  • Characteristic horse manure or barnyard odor
  • Most common causative agent of antibiotic associated diarrhea and pseudomembranous colitis
  • Specimen (fresh stool) should be planted on anaerobic blood agar and cycloserine cefoxitin fructose agar (CCFA)
  • Clinically significant when it produces toxins
answer
Clostridium difficile
question
  • Long, thin gram positive bacilli that branch like a tree and grow in a mass
    • Can break into short club-shaped rods
    • May have  abeaded or banded look
  • Reduces nitrates
  • Catalase and indole negative
  • Characteristic white molar tooth colony
  • Aerotolerant, but grows better under anaerobic conditions
  • Normal flora of upper respiratory, gastrointestinal, and female genital tracts
  • Causes purulent masses to form as weel as sinus tracts with discharge that can contain sulfur granule colonies
answer
Actinomyces israelii
question
  • Clubbed, pleomorphic, pallisading gram positive bacilli (anaerobic diphtheroids)
  • Catalase, indole, and nitrate positive
  • Aerotoleratn, but grows best in anaerobic environment
  • Normal skin flora
  • Most frequent blood culture contaminant
  • Causes acne and prosthetic infections in heart, valves, and joints
answer
Propionibacterium acnes
question
  • Gram negative coccobacilli or rods
    • Appear to ahve swellings or clear vacuoles in cells
  • Saccharolytic
  • Catalase positive
  • Bile resistant
  • Resistant to penicillin 2-unit disks
  • Obligate anaerobe
  • Grows well in 20% bile
  • Largest portion of normal gastrointestinal flora
  • Causes widespread tissue necrosis, appendicitis, and peritonitis
answer
Bacteriodes fragilis
question
  • Long, thin fusiform to very pleomorphic gram negative bacilli
  • Catalase negative
  • Resistant to vaoncomycin but sensitive to kanamycin and colistin
  • Growth not stimulated by 20% bile
  • Bread crumb-like colonies
  • Normal flora of oral tract, upper respiratory tract, and female genital tract
answer
Fusobacterium
question
  • Gram negative cocci in pairs, short chains, or clumps
  • Indole positive
  • High sensitivity to oxygen
  • Requires growing in an anaerobic chamber or glove box
  • Resistant to vancomycin but sensitive to kanamycin and colistin
  • Commensal flora in oral cavity and respiratory and gastrointestinal tract
  • Causes prosthetic joint infections
answer
Veillonella
question
  • Gram negative bacilli
  • Catalase poistive
  • Indole positive
  • Asaccharolytic
  • Will not grow on bile esculin
  • Susceptible to kanamycin
  • Brick red fluorescence under ultraviolet light
  • Requires incubation of 48 hrs. to 2 weeks
  • Normal flora of the oropharynx, nose, and urogenital and gastrintestinal tract
answer
Porphyromonas
question
  • Long, thin, branching gram positive bacilli
  • Catalase negative
  • Partially acid fast
  • Requires incubation at 35-37 degrees Celsius for 72 hrs. - 4 weeks in 10% CO2
  • Waxy, bumpy, velvety, yellow-orange colonies
  • Usually causes chronic repiratory and central nervous system infections and necrosis, abscesses, and skin infections
answer
Norcardia
question
  • Gram positive cocci in pairs and chains
  • Catalase negative
  • H2S positive
  • Reduces nitrate
  • Indole negative
  • Causes perodontitis and abdominal abscess
  • Can only grow on anaerobic PEA, CNA, or blood agar
  • Small, gray to white colonies on anaerobic blood agar with a sweet putrid odor
answer
Peptostreptococcus anaerobius
question
  • Gram negative bacilli
  • Catalase negative
  • Indole positive
  • Inhibited by 20% bile
  • Lipase positive
  • Ferments glucose
  • Young colonies are tan/buff in color, whereas older colonies develop a brown pigment
  • Can grow on laked blood agar
  • Predominant commensal organism in the oral cavity that can cause oral infections
  • Normal flora of urogenital tract that can cause infections of the head, neck, and lower respiratory tract
answer
Prevotella intermedia
question
  • Gram negative bacilli
  • Catalase negative
  • Indole negative
  • Esculin negative
  • Lipase negative
  • Black colonies on laked blood agar
  • Incubated for 2-3 weeks
  • Causes periodontal diseases, mouth abscesses, and endocarditis
  • Normal flora of upper respiratory tract
answer
Prevotella melaninogenica
question
  • Gram negative narrow bacilli, but Gram stain is poor
  • Gelatinase positive
  • Positive motility
  • Urease negative
  • Nitrate reduction negative
  • Cannot grow on blood agar, but can grow on buffered charcoal yeast extract (BCYE) agar
  • Requires L-cysteine and a soluble form of iron to grow
  • Cannot survive in dry environments
  • Circular, glistening, and convex colonies with an entire margin
  • Causes Pontiac fever and Legionnaire's disease
answer
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What is the right structure for an essay
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A paragraph is a related group of sentences that develops one main idea. Each paragraph in the body of the essay should contain:
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