stool
"Rice water stools" is characteristic of what infection?
Cholera .. Vibrio cholera
What is the most common cause of UTI?
E. coli
Cerebrospinal fluid (CSF) should be cultured
immediately, but if delayed the specimen
should be:
Incubated at 37 C and cultured ASAP
a naspharyngeal swab was collected from a child with a bad cough. After 3 days on Bordet - Gengou media colonies that were shiny and smooth like drops of mercury grew. What is the most likely organism
Bordetella pertussis
Which 3 genera of Enterobacteriaceae are usually
nonmotile at 36°C?
Shigella, Klebsiella, and Yersinia
Stool sample has identified Salmonella based on biochemical reactions. The lab wants to further test with antiserum A through G and Vi. There is only agglutination with the Vi antiserum.. What should be done next ?
Boil the suspension of the organism and retest to inactivate Vi antigen
Two species of Salmonella can cause Typhoid Fever: S. typhi and S. paratyphi. How can these two be differentiated?
S. Typhi H2S +
S. Paratyphi H2S -
What is the medium best suited for the recovery
of Yersinia enterocolitica from a patient with
gastroenteritis.
Cefsulodin–Irgasan–Novobiocin (CIN) agar
Which nonfermenting GNB is seen in infections due to ventilators or catheters , is Oxidase negative and may look like a lactose fermenter on MacConkey because of its purple color?
Acinetobacter
What organisms is the cause of
Lyme disease?
Borrelia burgdorferi
E. coli is isolated from a stool spEecimen, what sugar should this isolate be tested against ?
Sorbitol
E.coli O157:H7 does not utilize sorbitol while other E.coli do
The 2 Klebsiella species that cause infections are K. Pneumonia and K. oxytoca. What test is used to differentiate them and what are the reactions?
Indole
K. Pneumo -
K. Oxy +
!e aseptic collection of blood cultures requires
that the skin be cleansed with:
A. 2% iodine and then 70% alcohol solution
B. 70% alcohol and then 2% iodine or an
iodophor
C. 70% alcohol and then 95% alcohol
D. 95% alcohol only
B
Which organism is associated with
immunodeficiency syndromes and melioidosis
(a glanders-like disease in Southeast Asia and
northern Australia)?
Burkholderia pseudomallei
A gram-positive branching filamentous organism
recovered from a sputum specimen was found to
be positive with a modified acid-fast stain method.
What is the most likely presumptive identification?
A bloody stool cultured from a 26-year-old
woman after 3 days of severe diarrhea showed
the following results at 48 hours after being
plated on the following media:
MacConkey agar: little normal flora with many
non–lactose-fermenting colonies
Hektoen enteric agar: many blue-green colonies
Campylobacter blood agar and C. difficile agar:
no growth
Clear colonies (from MacConkey agar) tested
negative for oxidase, indole, urease, motility,
and H2S- The most likely identification is:
A. Shigella spp.
B. Salmonella spp.
C. Proteus spp.
D. E. coli
A
Biochemically, the Enterobacteriaceae are
gram-negative rods that: looking for 3 other characteristics
Ferment glucose, reduce nitrate to nitrite, and
are oxidase negative
A tube with semisolid medium that contains resazurin appears pink.. What does this indicate ?
The presence of Oxygen
The following results were obtained from a pure
culture of gram-negative rods recovered from the
pulmonary secretions of a 10-year-old cystic
fibrosis patient with pneumonia:
Oxidase = + Motility = +
Glucose OF (open) = + Gelatin hydrolysis = +
Pigment = Red Arginine dihydrolase = +
(nonfluorescent)
Growth at 42°C = + Flagella = + (polar,monotrichous)
Pseudomonas auruginosa
Egg yolk agar is used to detect which enzyme
produced by Clostridium species?
Lecithinase
What media is highly selective for the isolation of Vibrio species
TCBS ( thiosulfate - citrate- bile salt sucrose )
Which 3 Enterobacteriaceae genera are positive for phenylalanine deaminase?
Morganella, Providencia, and Proteus
Select the method of choice for recovery of
anaerobic bacteria from a deep abscess.
A. Cotton fiber swab of the abscess area
B. Skin snip of the surface tissue
C. Needle aspirate after surface decontamination
D. Swab of the scalpel used for debridement
C
The selective media for Legionella is
BCYE
Which gram-negative bacilli produce black
pigment and brick red fluorescence when exposed
to an ultraviolet light source?
A. Porphyromonas spp. and Prevotella spp.
B. Fusobacterium spp. and Actinomyces spp.
C. Bacteroides spp. and Fusobacterium spp.
D. All of these options
A