Which of the following bacteria are routinely tested for drug susceptibility in clinical laboratories?

• A. Bacillus subtilis
• B. Nitrosomonas europaea
• C. Staphylococcus aureus
• D. Rhizobium leguminosarum

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the concept of drug susceptibility testing (DST), which is performed to determine the sensitivity of bacteria to various antibiotics, guiding effective treatment choices.
2. Step 2: Identify the bacteria commonly associated with human infections that require clinical management, as these are the typical candidates for routine drug susceptibility testing in clinical laboratories.
3. Step 3: Recognize that Staphylococcus aureus is a common human pathogen known for causing a variety of infections and is frequently tested for antibiotic resistance, including methicillin-resistant Staphylococcus aureus (MRSA).
4. Step 4: Note that Bacillus subtilis, Nitrosomonas europaea, and Rhizobium leguminosarum are generally environmental or non-pathogenic bacteria and are not routinely tested for drug susceptibility in clinical settings.
5. Step 5: Conclude that among the options given, Staphylococcus aureus is the bacterium routinely tested for drug susceptibility in clinical laboratories due to its clinical relevance and potential for antibiotic resistance.