What laboratory technique is crucial for determining antibiotic susceptibility in Enterobacteriaceae?

• A. Culture and sensitivity testing
• B. Antimicrobial susceptibility testing, such as disk diffusion or broth microdilution
• C. Polymerase chain reaction (PCR)
• D. Serological testing

Answer: (B)

Determining antibiotic susceptibility in Enterobacteriaceae is critically important for guiding effective treatment. Antimicrobial susceptibility testing encompasses various methods, such as disk diffusion and broth microdilution, which are specifically designed to evaluate how well bacteria respond to different antibiotics.

Disk diffusion involves placing antibiotic-impregnated disks on an agar plate inoculated with the bacteria in question. The effectiveness of the antibiotics is indicated by the size of the inhibition zone around the disk. Broth microdilution, on the other hand, allows for the measurement of the minimum inhibitory concentration (MIC) of antibiotics against the bacteria by assessing whether bacterial growth occurs at various concentrations of the antibiotic in a liquid medium.

These methods provide direct insight into whether specific antibiotics can effectively inhibit or kill the bacterial strain, enabling tailored treatment plans. This is essential when treating infections caused by Enterobacteriaceae, as resistance patterns can vary widely among different strains.

While culture and sensitivity testing is a broader term that encompasses methods used to determine susceptibility, it may not specify the exact methods applied. Polymerase chain reaction (PCR) is primarily used for detecting specific genes or pathogens rather than for assessing antibiotic susceptibility. Serological testing focuses on detecting antibodies or antigens and is unrelated to direct antibiotic