Microbiology Review

An antibiotic used to suppress or kill contaminating fungi in media is ? A. Amphotericin B penicillin B. Chloramphenicol C. Cycloheximide D. Streptomycin

cycloheximide

The steam autoclave method of sterilization requires ?

15lb of pressure for 15 minutes

The proper blood-to-broth ratio for blood cultures to reduce the antibacterial effect of serum in adults is ?

1:10

Which selective medium is used for the isolation of gram-positive microorganisms? a Columbia CNA with 5% sheep blood b trypticase soy agar with 5% sheep blood c eosin methylene blue d modified Thayer-Martin

A. Columbia CNA with 5% sheep blood

Appropriate culture requirements for a specimen from a patient suspected of having tularemia include: a a media with cysteine such as buffered charcoal yeast extract agar b colistin nalidixic acid agar c Mueller-Hinton agar with 5% sheep blood agar d Regan-Lowe media

A. a media with cysteine such as buffered charcoal yeast extract agar

Upon review of a sputum Gram stain, the technician notes that the nuclei of all of the neutrophils present in the smear are staining dark blue. The best explanation for this finding is: a the slide was inadequately decolorized with acetone/alcohol b the sputum smear was prepared too thin c the cellular components have stained as expected d the iodine was omitted from the staining procedure

A. the slide was inadequately decolorized with acetone/alcohol

The Gram stain from a blood culture shows gram-positive cocci in chains. No growth occurs on blood agar plates incubated both aerobically and anaerobically. Additional testing should be done to detect the presence of: A. Staphylococcus saprophyticus B. Aerococcus urinae C. Abiotrophia defectiva D. Streptococcus pneumoniae

Abiotrophia defectiva

3 sets of blood cultures were obtained from an adult patient with fever and suspected endocaritis. The aerobic bottle of one set had growth of Staphylococcus epidermidis at 5 days of incubation. This indicates that; a. there was a low grade bacteria b. the organism is most likely a contaminant c. the patient has a line infection d. the blood culture bottles are defective

B. the organism is MOST likely a contaminant

Relapsing fever in humans is caused by ? A.Borrelia recurrentis B. Brucella abortus C. Leptospira interrogans D. Spirillum minus

Borrelia recurrentis

what medium can be used to recover Francisella tularensis ? A. Bordet-gengou agar B. Buffered charcoal yeast extract agar C. Loeffler agar D. MacConkey agar

Buffered charcoal yeast extract agar

A diabetic foot swab from an 82 year old woman with recurrent infections is submitted for culture. The Gram stain reveals: -many neutrophils, no squamous epithelial cells -many gram-negative bacilli -many gram-positive cocci in chains The physician requests that all pathogens be worked up. In addition to the sheep blood, chocolate and MacConkey agar plates routinely used for wound cultures, the technologist might also process a ? A. anaerobic blood agar plate B. BCYE agar plate C. CNA agar plate D. XLD agar plate

C. CNA agar plate

An organism that must be incubated in a microaerophilic environment for optimal recovery is ? A. Campylobactor jejuni B. E. Coli C. Pseudomonas aeruginosa D. Proteus mirabilis

Campylobacter jejuni

Gram stain examination from a blood culture bottle shows dark blue, spherical organisms in clusters. Growth on sheep blood agar shows small, round, pale yellow colonies. Further tests should include: a catalase production and agglutination test for Protein A b bacitracin susceptibility and serological typing c oxidase and deoxyribonuclease reactions d Voges-Proskauer and methyl red reactions

Catalase production and agglutination test for Protein A

A gram stain from a swab of a hand wound reveals: -moderate neutrophils -no squamous epithelial cells -moderate Gram-positive cocci in clusters -moderate large gram-negative bacilli What would be the appropriate media to selectively isolate each organism?

Columbia CNA, MacConkey

A bronchoscopy sample with the request for culture of Legionella is sent to the laboratory. The correct plating protocol is ? A. Culture on thiosulfate citrate bile salt media B. Incubate culture anaerobically C. Reject the specimen and request sputum D. Culture on buffered charcoal yeast extract agar with antibiotics

Culture on buffered charcoal yeast extract agar with antibiotics

An expectorated sputum is sent to the laboratory for culture from a patient with respiratory distress. The Gram stain of the specimen shows many squamous epithelial cells (>25/lpf) and rare neutrophils. The microscopic appearance of the organisms present include: -moderate gram-positive cocci in chains and diplococci -moderate gram negative diplococci -moderate palisading gram-positive bacilli all in moderate amounts This Gram stain is most indicative of: a a pneumococcal pneumonia b an anaerobic infection c an Haemophilus pneumonia d oropharyngeal flora

D. oropharyngeal flora

"Nutritionally variant" streptococci are ? A. Enterococci B. Group D enterococcus C.in the genera granulicatella and Abiotrophia

In the genera Granulicatella and Abiotrophia

A vaginal/rectal swab is collected from a pregnant patient to screen for group B streptococcus colonization. The best medium to inoculate the specimen to is ? A.CNA agar B. LIM broth C. Sheep blood D. Thioglycollate broth

LIM broth

Gram positive cocci in chains are seen on a gram stain from a blood culture. The organism grows as a beta-hemolytic colony. Further tests that could be performed include: A. PYR, bacitracin, and hippurate B. Catalase and agglutination test for Protein C. Oxidase and mass spectrometry

PYR, bacitracin, and hippurate

The best medium for culture of Bordetella pertussis is ? A. Phenylethyl alcohol agar B. Potassium tellurite blood agar C. Regan Lowe agar D. Tinsdale agar

Regan-Lowe agar

A 55 year old man presents to the emergency room with chest pain and is found to have suffered a heart attack. He has a past history of hypertension and high cholesterol. The patient is admitted and scheduled for a triple bypass procedure. During recovery, he becomes septic, developing a high grade fever and pneumonia. Gram positive cocci in clusters, isolated from both his lungs via an induced sputum specimen and the surgical incision, produce beta-hemolytic, catalase positive colonies on sheep blood agar. What is the most likely organism and the biochemical test performed to confirm the identification? A. Staph aureus and latex agglutination B. Strep pyogenes and PYR C. Strep agalactiae and latex agglutination

Staphylococcus aureus and latex agglutination

The most frequent cause of prosthetic heart valve infections occurring within 2-3 months after surgery is ?

Staphylococcus epidermidis

A gram positive coccus isolated from a blood culture is negative to: optochin, bacitracin, bile esculin hydrolysis, and catalase. But has a positive hippurate hydrolysis result. The organism is most likely ? A. Staph aureus B. Strep pneumoniae C. Strep pyogenes D. Strep agalactiae

Streptococcus agalactiae

Which of the following is the most appropriate organism and media combination? A. Vibrio species-skirrow B. Enterohemorrhagic E. Cool- phenylethyl alcohol (PEA) C. Campylobacter species- charcoal yeast extract D. Yersinia enterocolitica- CIN

Yersinia enterocolitica- cefsulodin-irgasan-novobiocin (CIN)

During the previous month, staphylococcus epidermidis has been isolated from blood cultures at 2-3 times the rate from the previous year. The most logical explanation for the increase in these isolates is that?

There has been a break in proper skin preparation before drawing blood for culture.

Vibrio parahaemolyticus is best isolated from feces on? A. EMB agar B. Hektoen enteric (HE) agar C. Salmonella shigella (SS) agar D. Thiosulfate citrate bile salts (TCBS) agar

Thiosulfate citrate bile salts (TCBS) agar

Acceptable specimens for culture of anaerobic bacteria includes ? A. Abscess B. Stool C. Clean catch urine D. Vaginal

abscess

The most appropriate method for collecting a urine specimen from a patient with an indwelling catheter is ?

aspirate urine aseptically from the catheter tubing

which of the following is the most appropriate organism and media combination? a. CSF- Columbia CNA, MacConkey b. endocervical- chocolate, Martin Lewis c. sputum- sheep blood Thayer-Martin, KV-laked blood d. urine- sheep blood chocolate, chocolate, Columbia CNA

b. endocervical- chocolate, Martin Lewis

a differential medium that can be used as a primary isolation agar producing predictable colored colonies that can be distinguished from other organism colony types describes ? A. Buffered charcoal yeast extract agar B. Blood phenylethyl alcohol agar C. Campylobacter blood agar D. Chromagar

chromagar

A wound specimen grew 2 colony types on sheep blood agar and a single , clear colony on MacConkey agar. Sheep blood agar growth was documented as: -colony type #1 swarming over entire plate, gram stain: gram negative rod -colony type #2 white colony, gram stain: gram positive cocci in clusters The best way to isolate colony type #2 from colony type #1 is to subculture ?

colony #2 to CNA and/or PEA

A sputum specimen is received for culture and gram stain. The gram-stained smear from this specimen has many squamous epithelial cells. The technologists best course of action would be to ?

call the patient care area and request a new specimen

The primary isolation of Neisseria gonorrhoeae requires: a anaerobic conditions b starch media c carbon dioxide d blood agar

carbon dioxide

Media used to support growth of Legionella pneumophilia should contain what additives ? A. X and V factors B. Hemin and vitamin K C. Charcoal and yeast extract D. Dextrose and lakes blood

charcoal and yeast extract

A cerebrospinal fluid specimen containing only 2 drops of CSF was collected by a lumbar puncture from a febrile 25 year old male and was submitted for a stat Gram stain and culture. The direct specimen Gram stain was reported as many neutrophils and no microorganisms seen. The remaining drop of CSF should be inoculated to ?

chocolate agar

A male urethral discharge specimen submitted for culture should be inoculated to what ?

chocolate and modified Thayer-Martin agar

which of the following specimen requests is acceptable? a. feces submitted for anaerobic culture b. Foley catheter tip submitted for aerobic culture c. rectal swab submitted for direct smear for gonococci d. urine for culture of acid-fast bacilli

d. urine for culture of acid-fast bacilli

Sodium polyanethol sulfonate (SPS) is used as an anticoagulant for blood cultures because ? A.inactivates penicillin and cephalosporins B. Prevents clumping of red cells C. Inactivates neutrophils and components of serum complement D. Facilitated growth of anaerobes

inactivates neutrophils and components of serum complement

Virus transport medium should contain agents that ?

inhibit bacterial and fungal growth

Campylobacter Jejuni isolation requires the fecal specimen be ?

inoculated onto selective plating media and incubated in reduced oxygen with added CO2 at 42C

When processing a patient specimen for Gram stain and culture, the proper use of a biological safety cabinet includes ?

not disrupting the air curtain barrier by keeping air flow and exhaust grills unobstructed.

What kinds of specimens are acceptable for anaerobic culture? A. Vaginal swab and eye swab B. Intraoral surface swab, leg tissue C.pleural fluid, brain abscess fluid D. Urine, sputum

pleural fluid, brain abscess fluid

A 21 year old patient presents with pharyngitis. A throat swab is collected and submitted for anaerobic culture. This specimen should be?

rejected as unacceptable

anticoagulants acceptable for use with blood, bone marrow, and synovial fluid specimens that are to be cultures include ? A.heparin and sodium citrate B. Sodium polyanethol sulfonate (SPS) and heparin C. Sodium polyanethol sulfonate and EDTA

sodium polyanethol sulfonate (SPS) and heparin

The optimal collection of a wound specimen for culture of anaerobic organisms is a ?

syringe filled with pus, obtained before administration of antibiotics

The most important variable in the recovery of organisms in adult patients with bacteremia (bacterial sepsis) is ?

the recommended volume of blood cultured

In general, anaerobic infections differ from aerobic infections because ? A. They usually arise from exogenous sources B. They are usually polymicrobic C. They usually respond favorably to aminoglycoside therapy

they are usually polymicrobic

A community hospital microbiology is processing significant numbers of stool cultures because of an outbreak of diarrhea following heavy rains and flooding in the county. A media that should be incorporated in the plating protocol is ? A. Colistin nalidixic acid for listeria B. Thiosulfate citrate bile salts sucrose for vibrio species C. MacConkey agar with sorbitol for campylobactor

thiosulfate citrate bile salts sucrose for Vibrio species

The principle difference between the Ziehl-Neelsen acid-fast stain technique and the Kinyoun acid-fast stain technique is the ? A. type of dyes used B. Type of microscope used to interpret stained smears C. Strength of acid decolonizer D. Use of heat to allow the due to penetrate organism

use of heat to allow the dye to penetrate organism