To screen or not to screen medical students for carriage of multidrug-resistant pathogens?

BACKGROUND: The aim of the study was to investigate the intestinal and nasal carriage of multidrug-resistant pathogens among medical students and its association with their lifestyle and demographic data.

MATERIALS/METHODS: In 2021, first- and final-year medical students were invited to the study. Two rectal swabs were used for detection of extended-spectrum beta-lactamases (ESBL)-producing, colistin-, tigecycline- or carbapenem-resistant gram-negative bacteria and vancomycin-resistant enterococci. A nasal swab was used for Staphylococcus aureus culture. S. aureus isolates were characterised by spa typing; gram-negative resistant isolates and methicillin-resistant S. aureus (MRSA) were subjected to whole genome short and/or long sequencing.

RESULTS: From 178 students, eighty (44.9%) showed nasal carriage of S. aureus (the most frequent spa type was t084 - 10.0%); two isolates were MRSA (spa types t044 and t3527). In rectal swabs, seven ESBL-producing strains were detected with a blaCTX-M-15 as the most frequent gene (n=4). 16 students were colonised by colistin-resistant bacteria, three isolates carried the mcr-1 gene (1.7%). The mcr-9 (10.7%, 19/178) and mcr-10 (2.2%, 4/178) genes were detected by qPCR, but only two colistin-susceptible mcr-10 positive isolates were cultured. The S. aureus nasal carriage was negatively associated with antibiotics and probiotics consumption. S. aureus and colistin-resistant bacteria were detected more frequently among students in contact with livestock.

CONCLUSIONS: Medical students can be colonised by (multi)drug-resistant bacteria with no difference between first- and final-year students. The participation of students in self-screening increases their awareness of possible colonisation by resistant strains and their potential transmission due to poor hand hygiene.