Exam 11: Laboratory Methods and Strategies for Antimicrobial Susceptibility Testing

In the microdilution broth dilution method,the interpretive criteria for the susceptible,intermediate,or resistant categories are based on the:

Assaying bacterial isolates for resistance genes by molecular methods:

Chromogenic cephalosporins are used to test for:

Daptomycin requires free calcium for its antibacterial action,is inhibited by pulmonary surfactant,and has activity against gram-positive bacteria.Gram-positive bacterial isolates can be tested for daptomycin susceptibility.For which type of infection should daptomycin susceptibility NOT be reported?

AST was performed using Mueller-Hinton agar with 5% sheep blood,35°C in 5% CO₂ from 24 hours according to standard protocols,what is the most likely identity of the organism being tested?

A bacterial suspension of 1.5× 10⁸ colony-forming units (CFUs)/mL is comparable with which McFarland standard?

Staphylococcal resistance to oxacillin is used to determine and report resistance to:

Antimicrobial susceptibility testing should be performed when

The minimum inhibitory concentration (MIC)result recorded in antimicrobial testing can be defined as the:

Detection of the haze produced by some resistant staphylococci and enterococci against methicillin and vancomycin can best be accomplished by:

A sputum culture from a cystic fibrosis patient grew Stenotrophomonas maltophila.A broth microdilution panel was inoculated.Antimicrobials tested included: ceftazidime,imipenem,ticarcillin-clavulanate,levofloxacin,and trimethoprim-sulfamethoxazole.After 20-hour incubation at 35°C in ambient air,no growth was seen in any well of the microtiter plate.Which of the following statements is true?

Enterococcal high-level gentamicin resistance predicts resistance to:

The antibiotic nitrofurantoin is effective against both gram-positive and gram-negative bacteria.This antibiotic is effective against which type of specimen?

Enterococcal resistance to ampicillin predicts resistance to:

What action should be taken for any isolate found to be nonsusceptible (NS)to a particular antimicrobial agent?

MIC endpoints can be reported results obtained by the following conventional AST methods EXCEPT:

Which antimicrobial susceptibility testing method uses a series of plates with different antimicrobial concentrations inoculated with multiple bacterial isolates per plate?

In the disk diffusion method of antimicrobial susceptibility testing,what is the standard medium used for testing most bacterial organisms?

The minimal bactericidal concentration (MBC)test:

S.pneumoniae was isolated from a spinal fluid sample from an inpatient.An oxacillin disk screening test was performed and the zone of inhibition measured 19 mm.Which action is most appropriate?