Detection of Macrolide-Resistant Genes and Its Clinical Outcomes in a Tertiary Teaching Hospital in Malaysia.

Background: is one of the leading causes of mortality and morbidity worldwide. The dramatic increase in in-vitro resistance of antimicrobial agents, particularly beta-lactams and macrolides, makes pneumococcal infections difficult to treat. The aim of this study was to describe the drug resistance rate, assess the prevalence of macrolide-resistant genes and review the clinical complications of pneumococcal infections among patients presented to Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia.

Methods: This is a descriptive cross-sectional study. All isolates collected from clinical specimens within a 1-year period were subjected to selected antimicrobial susceptibility testing using E-test strips. Polymerase chain reaction (PCR) analysis was conducted to detect macrolide-resistant determinants. The patient's clinical data were obtained from clinical notes.

Results: A total of 113 patients with a positive growth of were included in the study. The most common predisposing factors among them were bronchopulmonary diseases (15.9%). The penicillin-resistant rate was 7.1%, with minimal inhibitory concentration (MIC) ranging between 0.012 μg/mL and >32 μg/mL, and the erythromycin-resistant rate was 26.5%, with a MIC range of 0.03 μg/mL-> 256 μg/mL. Most of the erythromycin-resistant isolates were found to have the (A) gene (50.4%) and the (B) gene (20%); 16.7% had a combination of genes (A) and (B), and 13.3% had none of the two genes. Community-acquired pneumonia is the predominant type of pneumococcal infection. There was no significant association between the presence of macrolide resistance determinants and mortality ( = 0.837) or complications ( > 0.999 for empyema and cardiac complication; = 0.135 for subdural abscess).

Conclusion: The majority of erythromycin-resistant isolates were found to have the (A) gene, followed by the (B) gene and a combination of genes (A) and (B).