Asymptomatic Nasal Carriage of MRSA Among Romanian Medical Students: Prevalence and Sampling Technique Comparison

Nasal colonization plays a pivotal role in Methicillin-resistant Staphylococcus aureus (MRSA) carriage and transmission, especially in healthcare settings. Asymptomatic carriers amongst healthcare workers (HCWs) may serve as an important source for inner-hospital transmission, besides personal increased risks of endogenous infections. Medical students are an often-overlooked part of medical staff which, while not typically included in statistics concerning HCWs, are associated with increased patient contact and exposure to healthcare-associated pathogens. This study aimed to assess MRSA carriage rate amongst clinical-year medical students in the largest Romanian medical university, in addition to identifying potential risk factors. Nonetheless, a methodological aim was incorporated, in order to evaluate the effect of nasal swab pre-moistening with sterile saline on MRSA retrieval rate.

A cross-sectional study was conducted among clinical-year students from the 'Carol Davila' University of Medicine and Pharmacy in Bucharest, Romania. Participants completed a survey regarding potential risk factors and underwent nasal swab sampling, being randomly assigned to the two swab collection methods-dry swab or pre-moistened swab with sterile saline, randomization ensuring comparable baseline characteristics. Samples were inoculated on chromogenic MRSA agar media and incubated for 24-48 h at 35-37 °C. Isolates exhibiting characteristic growth further underwent coagulase testing, bacterial identification and methicillin resistance confirmation.

The study comprised 156 medical students, with an overall prevalence of asymptomatic MRSA nasal carriage of 5.76% (n = 9, 95% CI: 3.05-10.58%). No statistically significant associations were identified between MRSA carriage and hospital exposure. The prevalence of MRSA positive cultures was 5.00% (n = 4/80) among the conventional dry swab sampling subgroup, while the subgroup undergoing pre-moistened swab collection presented a 6.57% prevalence (n = 5/76), revealing no statistical significance (p = 0.74).

Asymptomatic MRSA carriage among medical students in this cohort suggests the potential role of this population in intra-hospital transmission. In addition, pre-moistening the nasal swab for collection of the sample showed no statistically significant impact on MRSA recovery rates, correlating with existing literature on the topic. These findings further emphasize the need for strict adherence to infection prevention and control measures in hospitals.