Macrolide resistance in Staphylococcus from COVID-19 patients in Santander

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• The COVID-19 pandemic saw increased use of macrolides, such as azithromycin.
• This intensive antibiotic use can drive the development of antimicrobial resistance (AMR) in bacteria.
• Gram-positive bacteria employ mechanisms like ribosomal RNA modification, efflux pumps, and enzymatic inactivation to resist macrolides.

Purpose of the Study:

• To determine the prevalence of macrolide resistance genes in Gram-positive bacteria isolated from COVID-19 patients.
• To investigate AMR patterns in Santander, Colombia.

Main Methods:

• A descriptive study analyzed 112 samples from COVID-19 patients (nasopharyngeal/oropharyngeal swabs, tracheal aspirates).
• 48 Gram-positive bacterial strains were isolated and tested for phenotypic and genotypic macrolide resistance.
• Specific resistance genes (ermA, ermB, ermT, mef(A/E)) were evaluated using molecular methods.

Main Results:

• Staphylococcus aureus (58.33%) and Staphylococcus epidermidis (31.25%) were the most common Gram-positive isolates.
• Nearly half (47.92%) of strains showed phenotypic resistance to azithromycin.
• A high genotypic resistance rate (81.25%) was observed, with ermB (58.33%) and ermT (45.83%) being the most frequent genes detected.

Conclusions:

• The study reveals a significant prevalence of macrolide resistance in Gram-positive bacteria from COVID-19 patients.
• This resistance is likely linked to the widespread use of macrolides during the pandemic.
• Urgent implementation of antibiotic stewardship programs is crucial to mitigate this public health threat.