Micro Rotation Quiz

HACEK organisms have the following characteristic

account for a small percentage of subacute endocarditis cases and grow best in capnophilic conditions

Ethylhydrocupereine hyrochloride (optochin) is a chemical used to differentiate

Streptococcus pneumoniae from viridans streptocci

Which Clostridium spp causes pseudomembranous or antibiotic-associated colitis

Clostridium difficile

A mucoid , lactose positive colony type on MacCocnkey agar that is indole negative, citrate positive, and non-motile is

Klebsiella pneumonia

A nasopharyngeal culture grows a predominance of beta hemolytic colonies on sheep blood agar at 18 h. The isolate is susceptible to a 0.04 unit of bacitracin. A Gram stain resulted in Gram positive cocci in chains. The most likely identification is

Streptococcus pyogenes

On a sheep-blood agar plate, Haemophilus influenzae satellites around colonies of:

Staphylococcus aureus

What structure is depicted in the image below?

Zygospore

A urine specimen from a maternity patient with the complaint of cystitis was received in the laboratory. The culture of this sample grew a lactose-positive, Gram-negative bacillus that was presumptively identified as Escherichia coli. Which combination of selective and differential media and resulting colony morphology is correct for this bacterium?

Hektoen enteric agar & salmon-orange colonies

A nonfermenting Gram-negative bacillus is isolated from a wound. The nitrate and oxidase are strongly positive. When plated on Mueller-Hinton media for an antibiogram, the organism produced a shiny blue-green pigment and was only susceptible to gentamicin and imipenem. The bacillus is probably

Pseudomonas aeruginosa

Quality control of antimicrobial susceptibility tests involves

testing standard reference strains that have defined antimicrobial susceptibility (or resistance) to the drugs tested.

TSI tubes were inoculated with isolates recovered from a stool specimen. They were incubated at 35°C o/n aerobically. Indicate the appropriate interpretation of the tubes shown. Tube "C" is an uninoculated control; NC = no change.

tube 1 - K/NC

tube 2 - K/A

tube 3 - K/A H2S

tube 4 - A/A Gas

The etiologic agent commonly associated with septicemia and meningitis of newborns is

Streptococcus agalactiae

Precipitates of diphtheria toxin and anti-toxin formed in agar gels are an in vitro means for detecting toxigenic strains of Corynebacterium diphtheriae. The name of this test procedure is the

Elek Test

A gram-negative rod was isolated from a wound infection caused by a bite from a pet cat. The following characteristic reactions were seen:

oxidase positive

indole positive

nitrate positive

ferments sucrose and glucose

catalase positive

ornithine decarboxylase positive

lysine decarboxylase negative

VP negative.

Which of the following is the most likely organism?

Pasteurella multocida

The most common vector-borne disease in North America and Europe transmitted by the bite of Ixodes ticks is caused by

Borrelia burgdorferi

Which of the following could be used as quality control for the PYR test?

Streptococcus pneumoniae and Enterococcus faecalis

Which of the following is NOT true of Francisella tularensis?

is easily identified by Gram reaction, colonial morphology, and carbohydrate fermentation patterns

Sodium hydroxide, Zephiran-trisodium phosphate, N-acetyl-L-cysteine-NaOH, and oxalic acid are associated with

digestion and decontamination of specimens for mycobacterial studies.

Which of the following enteric bacteria are transmitted by an insect vector?

Yersinia pestis

Ocular larva migrans is associated with infection by

Toxocara canis

Which group of tests differentiates Enterobacter spp. from Edwardsiella tarda?

H2S production, sucrose fermentation, indole and VP

Which anaerobic, Gram-negative bacilli produce black pigment on PEA, and brick red fluorescence when exposed to an ultraviolet light source?

Porphyromonas spp and Prevotella spp

Enterococcal high-level gentamicin resistance predicts resistance to

Aminoglycosides

The primary cause of community-acquired bacterial pneumonia in the USA is

Streptococcus pneumoniae

The enzyme deaminase removes the amine group from the amino acid phenylalanine, releasing free ammonia and phenylpyruvic acid. It is used to differentiate members of this genera from other Enterobacteriaceae

Proteus, Morganella & Providencia

What is a confirmatory test for a positive rapid plasmin reagin (RPR)?

FTP-ABS

The direct wet mount as part of the O&P (ova and parasite) examination

requires freshly passed, unpreserved stool.

Which of the following AST methods is quantitative and has the greatest flexibility?

E-test

A dairy farmer who has an intermittent fever, progressive weakness, and night sweats is suspected of having undulant fever. Which of the following bacteria is the likely cause of the infection?

Brucella abortus

Tellurite reduction is used for the presumptive identification of

Corynebacterium diphtheriae

Which mechanism is responsible for botulism in infants caused by Clostridium

botulinum?

ingestion of endospores in food or liquid

Which of the following characteristics is is used to identify Listeria monocytogenes?

tumbling motility viewed in a wet mount

umbrella motility in GI motility agar

block hemolysis in CAMP test

SMAC agar is used to distinguish E. coli O157:H7 from commensal E. coli by exploiting one difference. What characteristic does this media exploit?

ability to ferment sorbitol

Which of the following are not characteristics of Bartonella spp?

1, 2, and 3 are all correct (1) Associated with trench fever, bacillary angiomatosis, and cat-scratch disease. 2) bacteria multiple and persist in red blood cells. 3) cultivation includes the use of an Isolator Tube with subculture to chocolate and SBA plates incubated in high humidity at 35C for 14-28 days)

A stool specimen from a patient with watery diarrhea and abdominal cramps. Growth on XLD was colorless. Further testing indicated an oxidase -ve, non-motile bacterium. The results of inoculation of TSI are shown. What is the etiologic agent of these symptoms?

Shigella dysenteriae

A mold that produces colonies with a dark brown, green-black, or black appearance of both the surface and reverse side is classified as a:

dematiaceous mold

Which of the following organisms is often confused with the Salmonella species

biochemically and on plated media?

Citrobacter freundii

If glucose and maltose are utilized by a Gram negative, oxidase positive, b-lactamase negative diplococci, what is the species?

Neisseria meningitidis

Thayer-Martin, Martin-Lewis, and New York City media were all developed for the selective isolation of which organism?

Neisseria gonorrhoeae

Which of the following serve as the initial analysis for the identification of members of the Enterobacteriaceae?

Indole, oxidase, MacConkey, and blood agar

Two (2) enteric isolates were inoculated into nitrate broth and incubated at 35°C o/n aerobically.

Step 1 - alpha-naphthylamine and sulfanilic acid were added to the broth

Step 2 - zinc powder was added to the isolate A broth.

Which of the following indicate the correct interpretation for nitrate reduction?

Isolate A reduced nitrate to nitrogen gas and ammonia.

Isolate B reduced nitrate to nitrite.

Based on the hemolytic activity on this media and the Bacitracin disk reaction, identify the genus and species most likely isolated on this plate.

Streptococcus pyogenes

You observe the following structure in a Lactophenol Cotton Blue stain from sputum. What organism is this?

Coccidioides immitis

44. Which Gram positive bacterium may require cold enrichment in order to isolate it from placental and other tissue?

Listeria monocytogenes

The image shows a smear from a vaginal swab indicating the presence of small rods and clue cells. This indicates bacterial vaginosis due to:

Gardnerella vaginalis

Mycoplasmas are organisms without cell walls. Which antimicrobials would be

ineffective in treating infections involving this bacterium?

Penicillin

Systemic symptoms such as fever, weight loss, malaise, and loss of appetite can be present along with a widespread rash in patients suffering from

Secondary syphilis

Which of the following organisms are used as controls for Mycobacterium rapid-growers and slow-growers?

Mycobacterium fortuitum and M. tuberculosis

When humans have hydatid cyst disease, the causative agent and host classification are:

Echinococcus granulosus—accidental intermediate host

CHROMagar Orientation is expensive but very useful in the clinical lab because

It distinguishes among a group of bacteria associated with urinary tract infections.