Bacteriology Flashcards

Question

Group D streptococcus (not enterococcus)

Answer 1

Normal in GI tract Causes nosocomial UTI, wound infections, and bacteremia Oval Gram positive cocci in chains Usually nonhemolytic but can be alpha Esculin positive Most common S. gallolyticus (used to be S. bovis)

Answer 2

Normal in mouth, GI tract, female genital tract Oval GPC in pairs and chains Usually alpha or nonhemolytic, rarely beta Catalase negative Esculin positive, PYR positive, LAP positive Can grow in 6.5% NaCl Lancefield group D Intrinsically resistant to beta lactam antibiotics and are penicillin resistant Can become resistant to vancomycin 80% are E. faecalis, 15% are E. faecium ## Footnote Causes UTI, subacute endocarditis (following a severe enterococcal UTI)

Answer 3

Normal in upper respiratory tract of some Lancet shaped Gram positive diplococci, frequently encapsulated Polysaccharide capsule inhibits phagocytosis Round, translucent, dome shaped colonies Catalase negative Alpha hemolytic Bile solubility positive Sensitive to optochin Positive Quellung reaction (capsule visualization) Releases IgA proteases (enzyme the cleaves IgA and increases pathogenicity) No Lancefield group >80% serotypes based on capsular antigens Patients produce a rusty colored sputum which is indicative of Strep pneumo ## Footnote Causes pneumonia (hence the name), meningitis, otitis media (middle ear infection), sepsis in patients with Sickle cell anemia and who are post-splenectomy, and sinusitis

Answer 4

Normal in oral, respiratory, GI mucosa Opportunistic pathogens Frequently cause of subacute bacterial endocarditis Gingivitis and dental cavities Gram positive cocci in chains Usually alpha hemolytic but can be beta or nonhemolytic Catalase negative Resistant to optochin Bile solubility negative Certain strains (S. sanguis and S. mutans) may produce extracellular polysaccharides

Answer 5

Normal flora of mouth and GI/GU tracts Infections associated with trauma or surgery Most common sites are abdomen, head, and neck Gram positive cocci in pairs and chains Colonies are half the size of other strep Usually beta hemolytic but can be alpha or nonhemolytic Butterscotch or caramel odor Usually Lancefield group F PYR negative, VP positive 3 species - S. anginosus, S.constellatus, S. intermedius Grow better anaerobically

Answer 6

Usually contaminants Gram positive rods Large spreading beta hemolytic colonies with irregular edges (Medusa head) Whitish gray but can be pigmented Catalase positive Motile (usually) Must rule out B. anthracis

Answer 7

One of the most highly pathogenic microorganisms Contracted from contaminated hides, wool, and meat Very rare in the United States Large Gram positive rods with square ends, may be in chains Oval central to subterminal spores that aren't swollen Looks like bamboo Spores may not be seen in direct smear Large adherent, **nonhemolytic**, flat to slightly convex colonies with irregular borders Ground-glass appearance Stands up like beaten egg white when touched with a loop Catalase positive **Nonmotile** Potential bioterrorism organism Handle in BSC Submit to public health lab for confirmation **Helps rule out B. anthracis from B. cereus/other Bacillus spp**

Answer 8

Often environmental contaminant Can cause local and systemic infections and food poisoning Large Gram positive rods with square ends Oval central to subterminal spores that aren't swollen Looks like bamboo Large, adherent, beta hemolytic, flat to slightly convex colonies with irregular borders Ground-glass appearance Stands up like beaten egg white when touched with a loop Motile 2nd most important pathogen in the genus

Answer 9

Normal on skin and mucous membranes Opportunistic pathogens Irregular, slightly curved Gram positive rods, nonparallel sides, club shaped ends "Chinese letters" or palisades Facultative anaerobe Grows on most media Catalase positive Nonmotile Called diphtheroids because they resemble C. diphtheriae

Answer 10

Cause of diphtheria Rare in the United States Irregular, slightly curved Gram positive rods, nonparallel sides, club shaped ends "Chinese letters" or palisades Gray-black colonies with brown halos on Tindale agar Black colonies on cystine tellurite Loeffler medium stimulates growth and production of metachromatic granules Catalase positive Nonmotile Toxin producing Identification requires demonstration of toxin production

Answer 11

Hospital acquired pathogen Irregular, slightly curved Gram positive rods, nonparallel sides, club shaped ends "Chinese letters" or palisades Catalase positive Rapid sucrose urea negative Most commonly isolated diphtheroid Highly resistant to antibiotics

Answer 12

Meningitis and septicemia in newborns and immunocompromised people Common cause of food poisoning from deli meat and soft cheese Gram positive rods with parallel sides and rounded ends Arranged as singles, chains, or diphtheroid arrangements Tiny colonies with narrow zone of indistinct beta hemolysis Translucent and gray Catalase positive, hippurate hydrolysis positive, esculin positive, CAMP positive Tumbling motility on wet mount Umbrella growth in motility agar at RT but no at 35 degrees C Grows from 0.5-45 degrees C Cold enrichment may be used Catalase differentiates from Group B strep Motility differentiates from diphtheroids

Answer 13

Causes skin infections in immunocompetent people and invasive pulmonary and disseminated infections in immunocompromised people Gram positive rods with fine branching filaments and fragmentation Often look beaded Very slow growing Wrinkled, dry, chalky white appearance on BAP Beta hemolytic Catalase positive Partially acid fast N. brasiliensis most common species to cause skin infections N. asteroides most common species to cause lung infections

Answer 14

Gram negative diplococci Squished together to make a coffee bean shape Aerobic or facultative Pathogens are capnophilic Catalase positive, oxidase positive

Answer 15

Causes gonorrhea, salpingitis, and ophthalmia of the newborn Intracellular and extracellular Gram negative diplococci Diagnostic in urethral discharge from symptomatic males Culture confirmation required for females Grows on CHOC and Neisseria selective agars Colonies are small, grayish-white or tan Five different colony types so it could end up looking mixed Utilizes only glucose Susceptible to drying and cold **DO NOT REFRIGERATE** Culture is preferred for non-genital specimens and those from children Should confirm by different method (PCR)

Answer 16

Can be normal flora of the upper respiratory tract Common cause of meningitis in young adults Intracellular and extracellular Gram negative diplococci Grows on BAP, CHOC, and Neisseria selective media Colonies are bluish gray or tan May be mucoid Utilizes both glucose and maltose ONPG negative Handle in BSC Serogrouping by slide agglutination Bacterial antigen test available for detection but poor sensitivity and shouldn't replace a culture Vaccine is available

Answer 17

Normal in upper respiratory tract Rarely causes disease Gram negative diplococci Grows on BAP and CHOC at RT Grows on nutrient agar at 35 degrees C Not speciated if from respiratory specimens Must differentiate from pathogenic Neisseria when isolated on selective media or from normally sterile body site

Answer 18

Normal in upper respiratory tract of children Rare in adults Rarely causes disease Gram negative diplococci Will grow on Neisseria-selective media Resembles N. meningitidis but smaller Utilizes glucose, maltose, and lactose ONPG positive Easily misidentified as N. meningitidis (ONPG used to differentiate)

Answer 19

Normal in upper respiratory tract Causes respiratory infections in young, old, and compromised people Causes otitis media and sinusitis in children Gram negative diplococci Grows on BAP and CHOC at RT "Hockey puck" colonies (can be pushed around the agar with a loop) Catalase positive, oxidase positive No carbohydrate utilization ONPG negative DNase positive and butyrate positive (differentiates from Neisseria spp)

Answer 20

O antigen: somatic antigen - located in the cell wall, heat stable lipopolysaccharide, used for serological grouping of Salmonella and Shigella H antigen: flagellar antigen - located in the flagella (duh), heat labile proteins, used to serotype Salmonella K antigen: capsular antigen - located in the capsule (duh), heat labile polysaccharide that can mask the O antigen, prevents phagocytosis to increase virulence

Answer 21

Also known as Shiga toxin-producing (STEC) or verotoxin-producing (VTEC) Causes diarrhea, hemorrhagic colitis, hemolytic uremic syndrome (HUS) Most common cause of renal failure in children in the US May be fatal, especially in young or elderly patients Transmitted through undercooked meat, raw milk, and unpasteurized apple juice/apple cider Disease mechanism is toxin (Shiga or verotoxin) GMST will show RBCs but no polys

Answer 22

Causes "traveler's diarrhea" and diarrhea in infants Transmitted by contaminated food or water Disease mechanism is toxins GMST will show no polys or RBCs

Answer 23

Causes dysentery-like blood diarrhea in young children in areas of poor sanitation Transmitted through contaminated food or water Disease mechanism is invasiveness GMST will show polys, RBCs, and mucus

Answer 24

Causes diarrhea in infants Major pathogen in infants in developing countries Transmitted through formula and food contaminated with fecal material Disease mechanism is adherence/attachment GMST will show no polys or RBCs

Answer 25

Causes diarrhea in developing countries and chronic diarrhea in HIV-infected patients Nosocomial and community acquired transmission Disease mechanism is adherence/attachment Most labs cannot detect this pathogen

Answer 26

Causes diarrhea and UTI that is most common in children in developing countries Not much known about route of transmission Disease mechanism is adherence/attachment All together not well studied pathogen

Answer 27

Obligate aerobes Don't ferment carbohydrates (K/K on TSI) May be oxidizers or non-oxidizers Oxidation-fermentation media: either open tube pos/closed tube neg (oxidizer) or open tube neg/closed tube neg (non-oxidizer) Grows on BAP and CHOC in 24-48 hours Most grow on MAC as NLF Most are oxidase positive Resistant to a variety of antibiotics

Answer 28

Not usually normal flora Important cause of nosocomial infections (burns, wounds, RTI, UTI, bacteremia) Cause of swimmers ear and contact lens keratitis Long, thin, pale staining Gram negative rod Flat spreading colonies, beta hemolytic, with a metallic sheen on BAP Oxidase positive, catalase positive, and grape scented Can grow at 42 degrees Celsius (other species of Pseudomonas cannot) Produces pigment pyocyanin

Answer 29

Part of normal flora of skin and nasopharynx Opportunistic pathogen causing nosocomial infections like UTI, pneumonia, septicemia, and meningitis A. baumannii is the most common species Pleomorphic Gram negative coccobacilli in singles, pairs, or short chains Can be confused with N. gonorrhoeae or Moraxella Can produce purple tinged colonies that get confused with LF Oxidase negative, catalase positive

Answer 30

Not part of normal flora Colonizes immunocompromised and cystic fibrosis patients Common in hospitals causing nosocomial pneumonia Straight or slightly curbed slender Gram negative rods in singles or pairs Large, nonhemolytic colonies with a light yellow pigment on BAP Agar will have a lavender-green discoloration in areas of heavy growth Oxidase negative, catalase positive, rapid oxidizer of maltose, weaker oxidizer of glucose Has an ammonia odor

Answer 31

Most common cause of bacterial diarrhea Sources include chickens, raw milk, and pets Faintly staining, "seagull wing" shaped, Gram negative rod Microaerophilic and capnophilic Grown on CAMPY BAP at 42 degrees C but can also grow at very low temperatures Slow growing so plates are held for 3 days Darting corkscrew motility, oxidase positive. catalase positive, and Hippurate positive Hippurate hydrolysis is used to speciate

Answer 32

Similar to C. jejuni, but less severe Usually foodborne Rarely differentiated from C. jejuni Hippurate hydrolysis negative

Answer 33

Causes bacteremia in immunocompromised and elderly patients Most often isolated in blood cultures Hold plates for 2 weeks and inhibited on CAMPY BAP Oxidase positive, catalase positive Hippurate hydrolysis negative

Answer 34

Causes gastritis, duodenal and peptic ulcers Possible risk factor for gastric carcinoma Curved, slender, Gram negative rod Grows on nonselective media at 37 degrees C Rarely cultured Tested with rapid urease tests on gastric biopsy, urea breath test, histology, PCR, or serology testing

Answer 35

Causes cholera (acute diarrhea, dehydration, electrolyte imbalance) Transmitted by contaminated water and seafood Uncommon in the US but may be seen in coastal areas Small comma-shaped Gram negative rods in direct smears Straight pleomorphic Gram negative rods in culture Nonhalophilic (doesn't require NaCl to grow) Grows as large yellow colonies on TCBS agar (ferments sucrose) Characteristic "rice water" stools

Answer 36

Second most serious type of vibrio infection Affects the immunocompromised or individuals with liver disease by causing septicemia following the consumption of raw oysters and water associated wound infections Affects healthy individuals by causing gastroenteritis Straight or curved Gram negative rods Halophilic (requires the addition of Na) Most are green on TCBS

Answer 37

Causes gastroenteritis from contaminated seafood or water associated wound infections Straight or curved Gram negative rods Requires 1% NaCl for growth Blue-green colonies on TCBS (doesn't ferment sucrose)

Answer 38

Causes gastroenteritis and wound infections, often related to aquatic exposure Can also cause septicemia and meningitis Straight or curved Gram negative rods Grows beta hemolytic on BAP, NLF on MAC Doesn't grow on TCBS Oxidase positive

Answer 39

Causes gastroenteritis from contaminated water or seafood Bacteremia and meningitis in immunocompromised and neonates Pleomorphic Gram negative rods in singles, pairs, short chains, or long filaments Grows on BAP, CHOC, and MAC Has biochemical and antigenic similarities to Shigella (obvi)

Answer 40

Normal flora of upper respiratory tract Mode of transmission is respiratory droplets spread from person to person Causes sinusitis, otitis media, pneumonia, and bronchitis often in elderly patients Type B is a common cause of pneumonia and meningitis in children 5 months to 5 years where Hib vaccine is not available Small, pleomorphic Gram negative coccobacilli to long filaments with capsules Grows on CHOC with translucent, moist, tannish colonies Mousy or bleach like odor Can demonstrate satellitism with staph on BAP

Answer 41

Both cause conjunctivitis (pink eye) H. influenzae biotype aegyptius also causes Brazilian purpuric fever Difficult to differentiate from H. influenzae

Answer 42

Normal flora of upper respiratory tract Low incidence of pathogenicity Small, pleomorphic Gram negative coccobacilli to long filaments Colonies are larger, dry, and tannish

Answer 43

Never normal flora Mode of transmission is person to person by sexual contact Causes chancroid (sexually transmitted disease) Small Gram negative coccobacilli with bipolar staining May resemble schools of dish or railroad tracks Difficult to culture and is identified by PCR Virulence factors are unknown but it is thought to have a capsule and produce toxins that allow for attachment and penetration in the host cells

Answer 44

Causes "trench fever", relapsing fever, bacteremia, endocarditis, and cat-scratch fever Intracellular Gram negative coccobacilli Not cultured (takes 9-40 days to grow)

Answer 45

Causes whooping cough in children and adults Small Gram negative coccobacilli Grows on Bordet-Gengou and Regan-Lowe (charcoal horse blood) after 3-7 days DTaP vaccine protects against it

Answer 46

Causes brucellosis (undulant fever) from unpasteurized milk or contact with infected goats, cows, hogs, and dogs Tiny, faintly staining Gram negative coccobacilli Most often isolated from blood cultures or biopsies of reticuloendothelial tissue Blood cultures are to be incubated for 3 weeks Oxidase positive, urease positive Level 3 pathogen and possible bioterrorism agent

Answer 47

Causes tularemia (rabbit fever) Infection from bite from infected tick or from handling infected animals Pale staining, small, pleomorphic, intracellular Gram negative coccobacilli with bipolar staining Grows on special media that is enriched with glucose and cystine, TM, and BCYE agars Grows small transparent colonies after three days Level 3 pathogen that needs to be sent to public health for confirmation

Answer 48

Normal flora of female genital tract Associated with bacterial vaginosis (BV) when it and anaerobic Gram negative rods are predominant and Lactobacillus is absent Linked to maternal and neonatal infections, bacteremia, and rare UTI Small, pleomorphic, Gram variable rods Not recommended for diagnosis of BV Grows on BAP, PEA, CNA, human blood Tween (HBT) Produces diffuse beta hemolysis only on media containing human blood Catalase and oxidase negative

Answer 49

Cause of Legionnaire's disease (duh) and Pontiac fever Found in water (air conditioners, showerheads, and whirlpools) Contracted by inhalation of aerosol Small, pleomorphic, weakly staining Gram negative rods Grows on BYCE in 3-4 days and has a pale yellow-green fluorescence with Wood's lamp Oxidase positive Identified by immunofluorescent stain or urine antigen test

Answer 50

Contracted by bite or scratch of cat or dog or contact with infected carcass Causes soft tissue infections, respiratory infections, or bacteremia Produces an endotoxin and a capsule that contributes to pathogenicity Pleomorphic Gram negative coccobacilli with bipolar staining Grows on BAP and CHOC, but not MAC Also grows well in blood culture media, thioglycolate broth, and BHI broth Incubate in ambient air or 35-37 degrees C with CO2 for a minimum of 24 hours Has a musty/mushroom odor Oxidase, catalase, and indole positive

Answer 51

Formerly Peptostreptococcus magnus Normal flora on skin and mouth, intestines, and female genital tract Most commonly isolated and most pathogenic anaerobic Gram positive cocci Associated with skin infections, decubitus ulcers, septic arthritis, bone infections following orthopedic surgery, oral infections, female genital tract infections, and bacteremia Gram positive cocci in singles, pairs, tetrads, and clusters (resembles staph Can take up to 48 hours to grow Catalase and indole negative Resistant to SPS

Answer 52

Normal on skin and in mouth, GI, and GU tracts Mixed infections of skin, soft tissues, GI tract, female genital tract, bones, joints, lungs, and brain Tiny Gram positive cocci in chains (resembles strep) Sweet odor Sensitive to SPS

Answer 53

Formerly Peptostreptococcus asaccharolyticus Normal on skin and in GI/GU tracts Associated with obstetric and gynecological infections Gram positive cocci in pairs, short chains, tetrads, and clusters Yellow colonies Musty odor Indole positive Resistant to SPS

Answer 54

Infects the brain, face, lungs, and genitals Short or long Gram positive rods Branched or unbranched Banded appearance Can break into club shapes resembling diphtheroids Sulfur granules may be seen in discharge Crush and stain to reveal characteristic Gram stain morphology "Molar tooth" colonies

Answer 55

Botulism due to ingestion of toxin in inadequately cooked or improperly canned foods Infant botulism due to ingestion of spores in honey Wound botulism from injection drug use Gram positive rod with oval subterminal spores Reportable disease with toxin testing at public health labs

Answer 56

Causes antibiotic-associated diarrhea and pseudomembranous colitis Thin Gram positive rod that may form chains with rare oval subterminal spores Yellow ground glass colonies on cycloserine cefoxitin fructose agar (CCFA) Usually not cultured and must demonstrate toxin production for it to be a critical call

Answer 57

Normal in GI tract Causes gas gangrene and food poisoning Large Gram positive rods with blunt ends in chains resembling "box cars" Tendency to stain Gram negative Usually no spores seen Most commonly isolated Clostridium species Has a double zone of hemolysis on BAP

Answer 58

Causes tetanus and deep wound infections from soil Gram positive rod with swollen terminal spores resembling "drum sticks" or "tennis rackets" Becomes Gram negative after 24 hours Rare in the US because of DTaP vaccine

Answer 59

Normal skin flora Common contaminant of blood cultures Cause of acne and infections associated with artificial joints, catheters, shunts, artificial heart valves, keratitis, bacteremia, and endocarditis Club shaped, pleomorphic Gram positive rod Most common anaerobic Gram positive rods Catalase and indole positive

Answer 60

Normal in mouth and GI tract Predominant flora of vagina during reproductive years Produces lactic acid, maintains vaginal pH Absence in vagina predisposes to bacterial vaginosis and yeast infections Rare cause of endocarditis and septicemia in immunocompromised Pleomorphic, long, thin, non-spore forming Gram positive rods Aerotolerant anaerobes Grow better under anaerobic conditions Colonies vary greatly May resemble S. viridans Catalase negative (differentiates from diphtheroids)

Answer 61

Normal flora of upper respiratory tract and GI/GU tracts Usually in mixed cultures Can cause infections in immunocompromised patients Tiny Gram negative diplococci resembling Neisseria May show weak red fluorescence under UV light Doesn't grow on KVLB Usually doesn't reduce nitrates

Answer 62

Cause of mixed infections below the diaphragm Pleomorphic, pale, irregularly staining Gram negative rods Most common anaerobe isolated Resistant to bile Hydrolyses esculin Turns BBE brown

Answer 63

Pulmonary infections, brain abscesses, and oral lesions Gram negative rod F. nucleatum is long and thin with tapered ends (spindle shaped) Indole positive Most fluoresce chartreuse under UV light

Answer 64

Causes head, neck, and pleuropulmonary infections Gram negative coccobacilli Slow growing Brown to black colonies on BAP Some fluoresce brick-red to orange under UV light Doesn't grow on KVLB

Answer 65

Causes head, neck, and pleuropulmonary infections Gram negative coccobacilli Slow growing Some are pigmented Brown to black on BAP and KVLB Some fluoresce brick-red to orange under UV light Doesn't grow on BBE

Answer 66

Most common sexually transmitted bacterial infection in the US Causes trachoma, lymphogranuloma venereum, nongonococcal urethritis, and pelvic inflammatory disease Can also cause pneumonia and conjunctivitis in newborns Obligate intracellular parasite Epithelial cells are needed for culture (wooded swabs cannot be used because they are toxic) Can be simultaneously tested with N. gonorrhoeae

Answer 67

Third most common cause of acute RTI Obligate intracellular parasite Risk factor for Guillain-Barre Syndrome May also be a risk factor for cardiovascular disease

Answer 68

Causes psittacosis (Parrot fever), very rare in the US Obligate intracellular parasite spread by birds (duh)

Answer 69

Causes relapsing fever (recurrentis = recurring) Diagnosed through Giemsa or Wright stained blood smears Transmitted through ticks and lice

Answer 70

Causes Lyme disease (erythema chronicum migrans, neurological and cardiac abnormalities, and arthritis) Grows on modified Kelly medium Serology testing is most common identification method Most commonly reported tick-borne infection in the US Vector is the Ixodes tick

Answer 71

Cause of syphilis Will not grow on artificial media Diagnosed through darkfield microscopy with fluorescent stain Worldwide problem

Answer 72

Causes Weil's disease (infectious jaundice, leptospirosis) Diagnosed through culture (growth = turbidity below surface of semisolid Fletcher's medium) Cultures are kept for 6 weeks Is a zoonotic disease that is transmitted by urine of infected animals Organism can be found in blood and CSF during first week of infection, then found in the urine

Answer 73

Causes primary atypical pneumonia or "walking pneumonia" Smallest free living cells Lack cells walls, pleomorphic, and not visible by Gram stain Culture is rarely performed because they are so difficult to grow (can take 21 days or more if successful) Usually diagnosed by serology

Answer 74

Causes urogenital tract disease Only species that will grow on BAP and CHOC but may require 4 days for growth Pinpoint translucent colonies easily overlooked "Fried-egg" colonies can be seen with stereomicroscope after staining with methylene blue

Answer 75

Causes urogenital tract disease Granular brown appearance on A8 agar because of urease production