question
Pharyngitis
answer
Group A streptococci (children)
Virus (adults)
Bacterial pharyngitis (S. pyogenes):
Exudates, fever, painful adenopathy, no cough, throat culture
Viral pharyngitis:
Common cold symptoms
Corynebacterium diphtheriae
Virus (adults)
Bacterial pharyngitis (S. pyogenes):
Exudates, fever, painful adenopathy, no cough, throat culture
Viral pharyngitis:
Common cold symptoms
Corynebacterium diphtheriae
question
Group A Streptococcus (GAS)
answer
...
question
Carbohydrate utilization tests would be necessary to assist in the ID of this bacterial cause of otitis media in young children
answer
Moraxella catarrhalis
question
The majority of bronchitis infections are caused by
answer
Viruses
question
Important fungal cause of chronic pneumonia
answer
Blastomyces dermatitidis
question
Most common cause of community-acquired pneumonia in children > 3 months of age
answer
Respiratory syncytial virus
question
Most common cause of community-acquired pneumonia in adults
answer
Streptococcus pneumoniae
question
Medium required for growth of pertussis agent
answer
Bordet-Gengou
question
Selective medium required for growth of Legionella pneumophila
answer
BCYE
question
Most common cause of AIDS-associated respiratory infection
answer
Pneumocystis carinii
question
Emerging viral respiratory pathogen with 100% seroprevalence in adults
answer
Human metapneumovirus
question
Beta-hemolytic, catalase-negative, gram-positive coccus
answer
Streptococcus pyogenes
question
Normal flora of the ears
answer
Pseudomonas aeruginosa
question
Gram-positive rod that is a pathogen of the upper respiratory tract
answer
Corynebacterium diphtheriae
question
A urine sample from an elderly patient grew 6 x 10e5 cfu/mL of an oxidase negative GNR. History revealed the patient undergoes frequent catheterizations due to diabetic nephropathy. You would expect the following results on workup of the MOST LIKELY causative organism.
answer
GNR, lactose fermenter, indole neg, urease pos, citrate pos, H2S neg, nonmotile
Klebsiella
Klebsiella
question
A 21 year old college student presented to the wellness clinic with symptoms of cystitis. A midstream clean catch urine sample was collected and sent to the micro lab. Culture on SBA revealed 4+ growth of two similar but discrete colony types: small, entire, white and gamma hemolytic. Which one test would differentiate between the pathogen and the contaminant (NF)?
answer
Novobiocin
S. saprophyticus - pathogen (R)
S. epidermidis - NF (S)
S. saprophyticus - pathogen (R)
S. epidermidis - NF (S)
question
A possible bioterrorism agent that is the cause of pneumonic plague, this gram-negative rod exhibits bipolar staining with Giemsa or Wright stains
answer
Yersinia pestis
question
Which of the following testing algorithms are recommended by the CDC for testing a patient presenting with primary syphilis?
answer
RPR pos, EIA pos = diagnostic
question
Aerotolerance testing uses CHOC agar incubated in an aerobic environment and ANA-BAP in an anaerobic environment. Which of the following organisms will NOT grow on the CHOC agar?
answer
Clostridium perfringens
question
Pneumococcal meningitis can be identified by
answer
Catalase, optochin
S. pneumoniae - S
S. pneumoniae - S
question
Directly observed therapy is used for infection with
answer
Mycobacterium tuberculosis
question
Campylobacteriosis is zoonosis
answer
True
Poultry
Poultry
question
Of the following upper respiratory tract pathogens, which is a gram negative diplococcus?
answer
Neisseria gonorrhoeae
Also:
Haemophilus influenzae
type A, type B
Haemophilus parainfluenzae
Also:
Haemophilus influenzae
type A, type B
Haemophilus parainfluenzae
question
Group A strep (GAS) causes necrotizing fasciitis
answer
True
question
An acceptable expectorated sputum sample for culture would contain the following:
answer
< 10 squamous epithelial cells & at least 25 PMNs/low power field
question
Nocardia
answer
Stain w/ a beaded gram variable appearance
Branched hyphae
Reduce nitrate to nitrite
Partially acid fast
Facultative intracellular
Species are differentiated by patterns of proteolytic hydrolysis or acid fermentation of several substrates
Pneumonia
N. asteroides accounts for 90% of infection cases
Pulmonary - N. asteroides
Cutaneous - N. brasiliensis
Trimethoprim-sulfamethoxazole antibiotic of choice
Branched hyphae
Reduce nitrate to nitrite
Partially acid fast
Facultative intracellular
Species are differentiated by patterns of proteolytic hydrolysis or acid fermentation of several substrates
Pneumonia
N. asteroides accounts for 90% of infection cases
Pulmonary - N. asteroides
Cutaneous - N. brasiliensis
Trimethoprim-sulfamethoxazole antibiotic of choice
question
Aerobic Actinomycetes
answer
Nocardia
Streptomyces
Nocardiopsis
Actinomadura
Streptomyces
Nocardiopsis
Actinomadura
question
Aerotolerant (anaerobic) actinomycetes
answer
Actinomyces
Propionibacterium propionicum
Propionibacterium propionicum
question
Streptomyces
answer
Beaded, branching Gram-positive filamentous bacteria with well-developed substrate mycelium; produce aerial mycelium with chains of spores
Not partial acid-fast
Do not reduce nitrate to nitrite
Rarely causes disease but is used as a source of antibiotics
S. somaliensis - actinomycotic mycetoma
Not partial acid-fast
Do not reduce nitrate to nitrite
Rarely causes disease but is used as a source of antibiotics
S. somaliensis - actinomycotic mycetoma
question
Actinomadura
answer
Colony is glabrous, waxy, membranous or mucoid, with a heaped and folded appearance, pigmented, red, pink, yellow, orange, white or tan
Not acid-fast
A. madurae, A. pelletieri, A. dassonvillei
Granulocytic infiltrates within craterlike openings in skin and subcutaneous tissue; sinus tracts form
A. madurae - large, yellow granules
A. pelletieri - small, red granules
Not acid-fast
A. madurae, A. pelletieri, A. dassonvillei
Granulocytic infiltrates within craterlike openings in skin and subcutaneous tissue; sinus tracts form
A. madurae - large, yellow granules
A. pelletieri - small, red granules
question
Actinomyces
answer
Aerotolerant anaerobic actinomycetes, branching gram + rods
NF of mouth
Formation of abscesses in the mouth, lungs or the GI tract and/or granulomas that eventually develop draining abscesses
Yellow sulfur granules
Molar tooth colonies
NF of mouth
Formation of abscesses in the mouth, lungs or the GI tract and/or granulomas that eventually develop draining abscesses
Yellow sulfur granules
Molar tooth colonies
question
Propionibacterium propionicum
answer
Aerotolerant anaerobic actinomycetes: Diphtheroid appearance or filaments and branching rods
Oral NF
Cause of actinomycosis
Penicillin is drug of choice
Oral NF
Cause of actinomycosis
Penicillin is drug of choice
question
Mycobacterium
answer
Slender, slightly curved or straight, non motile rod that does not form spores
Acid fast
Aerobic
Acid fast
Aerobic
question
Mycobacterium tuberculosis (Mtb) complex
answer
M. tuberculosis
M. bovis
M. africanum
M. microti
Intracellular pathogens
M. bovis
M. africanum
M. microti
Intracellular pathogens
question
Nontuberculous mycobacteria (NTM)
answer
Mycobacteria Other Than Tuberculosis Complex (MOTT)
Photochromogens (Group I)
Scotochromogens (Group II)
Nonphotochromogens (Group III)
Rapid growers (Group IV)
Photochromogens (Group I)
Scotochromogens (Group II)
Nonphotochromogens (Group III)
Rapid growers (Group IV)
question
Definitive ID of M. tuberculosis
answer
Rough, buff, nonpigmented colonies on Lowenstein-Jensen (LJ) or Middlebrook media after 14-28 days of incubation at 37°C
Appearance of microcolonies with serpentine cords on Middlebrook 7H10 or 7H11 media after 5-10 days
Niacin
Nitrate to nitrite
Growth in T2H
Catalase negative
Inhibited by NAP
Appearance of microcolonies with serpentine cords on Middlebrook 7H10 or 7H11 media after 5-10 days
Niacin
Nitrate to nitrite
Growth in T2H
Catalase negative
Inhibited by NAP
question
M. bovis differentiation
answer
Niacin negative
Nitrate negative
Growth inhibition by T2H
Nitrate negative
Growth inhibition by T2H
question
Photochromogens (Group I)
answer
M. kansasii, M. marinum, M. asiaticum
When grown in the dark, colonies are buff but in the light they become pigmented
pulmonary disease
When grown in the dark, colonies are buff but in the light they become pigmented
pulmonary disease
question
Scotochromogens (Group II)
answer
M. gordonae, M. scrofulaceum, M. szulgai
Produce pigmented colonies whether grown in light or dark
Most are non pathogenic
Produce pigmented colonies whether grown in light or dark
Most are non pathogenic
question
Nonphotochromogens (Group III)
answer
Do not produce pigment under any growth conditions
Nonpathogens
M. terrae, M. triviale, M. nonchromogenicum, M. gastri
Rare pathogens
M. shimoidei, M. celatum, M. xenopi, M. ulcerans
Most common pathogens are included in the Mycobacterium avium complex
M. avium, M. intracellulare (MAC)
Nonpathogens
M. terrae, M. triviale, M. nonchromogenicum, M. gastri
Rare pathogens
M. shimoidei, M. celatum, M. xenopi, M. ulcerans
Most common pathogens are included in the Mycobacterium avium complex
M. avium, M. intracellulare (MAC)
question
Rapid growers (Group IV)
answer
M. fortuitum, M. chelonae, M. smegmatis
Colonies appear on media in 7 days or less
Colonies appear on media in 7 days or less
question
Mycobacterium leprae
answer
Leprosy (Hansen's disease)
Tuberculoid or tuberculous leprosy - localized infection
Lepromatous leprosy - slow, progressive life-threatening, disseminated infection
Tuberculoid or tuberculous leprosy - localized infection
Lepromatous leprosy - slow, progressive life-threatening, disseminated infection