Molecular Detection and Antibiotic Sensitivity Patterns in Methicillin Resistance Staphylococcus aureus Colonizing Pregnant Women in Eastern Province, Sri Lanka

Abstract

Background: Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) are pathogens capable of causing a wide range of infections, from localized issues to life-threatening sepsis. In Sri Lanka, data on MRSA colonization among pregnant women are limited, with most existing studies focusing on hospital-acquired infections or non-pregnant populations. Objectives: To determine the MRSA colonisation rate in pregnant women admitted for delivery with a gestational age of more than 35 weeks, and to describe their antibiotic sensitivity patterns and the presence of the mecA gene Methods: This descriptive cross-sectional study involved 235 pregnant women admitted for delivery at the Teaching Hospital, Batticaloa, in the Eastern Province, Sri Lanka, from May to August 2023. Swabs were collected from the nasal, rectal, and vaginal sites of each participant. Staphylococcus aureus and MRSA strains were identified using routine microbiological methods and disc-diffusion antibiotic sensitivity testing (ABST). Vancomycin minimum inhibitory concentration (MIC) was determined for all MRSA isolates. PCR was performed to detect the mecA gene in phenotypically identified MRSA isolates with a zone diameter of ≤21 mm. Statistical analysis was conducted using SPSS version 27.0. Results: Out of 235 pregnant women, 36 (15.32%) were colonized with Staphylococcus aureus. Among them, 9 (3.83%) showed colonisation only in the nasal mucosa, 24 (10.21%) in the recto- vaginal mucosa, and 3 (1.28%) at both sites. A total of 36 MRSA isolates were identified from 33 pregnant women. From the nasal and recto-vaginal sites, 12 (5.11%) and 24 (10.21%) MRSA isolates were identified, respectively. Therefore, the MRSA colonisation rate was 14.04% (95% CI: 9.61%-18.47%). Antibiotic sensitivity patterns for MRSA were as follows: clindamycin (69.44%), ciprofloxacin (88.89%), co-trimoxazole (86.11%), tetracycline (94.44%), and erythromycin (2.78%). All 36 MRSA isolates (100%) were sensitive to vancomycin (≤2 μg/mL). PCR revealed that 34 out of 36 (94.44%) MRSA isolates had the mecA gene. Conclusion: This study found a notably high MRSA colonization rate of 14.04%. These findings highlight the need for colonisation control strategies and regular MRSA screening in maternity wards, as the detected rate is considerably higher than previously reported levels.