D test: a simple test with big implication for Staphylococcus aureus macrolide-lincosamide-streptograminB resistance...

Area of Science:

• Microbiology
• Antimicrobial Resistance
• Clinical Diagnostics

Background:

• Staphylococcus aureus is a significant human pathogen, with methicillin-resistant S. aureus (MRSA) posing a particular challenge.
• Macrolide lincosamide streptogramin resistance (MLSB) and macrolide streptogramin resistance (MSB) are important resistance mechanisms in S. aureus.
• Clindamycin and streptogramin are critical therapeutic options for MRSA infections.

Purpose of the Study:

• To evaluate the D test as a method for differentiating constitutive and inducible MLSB, and MSB in Staphylococcus aureus.
• To assess the utility of the D test in clinical settings for guiding antimicrobial therapy.

Main Methods:

• The D test utilizes the disc diffusion method on Mueller Hinton agar.
• Erythromycin (macrolide) and clindamycin (lincosamide) discs are placed adjacent to each other.
• Interpretation of zone of inhibition and zone flattening identifies different resistance phenotypes.

Main Results:

• D test positive with zone flattening indicates constitutive or inducible MLSB.
• D test negative with clindamycin resistance suggests MSB.
• The test distinguishes between different MLSB types and MSB, aiding in resistance characterization.

Conclusions:

• The D test is a simple, high-throughput method for identifying MLSB and MSB in Staphylococcus aureus.
• Accurate identification of resistance mechanisms is crucial for effective treatment of S. aureus infections, especially MRSA.
• The D test provides valuable information for antimicrobial stewardship and patient management.