Methicillin-resistant Staphylococcus aureus in the environment of public transport: data from the metropolitan network in Lyon, France

Methicillin-resistant Staphylococcus aureus (MRSA) is involved in community-acquired and nosocomial diseases. The means of MRSA transmission and dissemination in the community remain uncertain. Studies have shown that public transport systems could be a source of MRSA and may serve as a potential source for community-acquired MRSA infections. This study aimed to investigate MRSA contamination on Lyon's metropolitan network (Metro) in France. Hand-touched surfaces were sampled with sterile swabs (Transystem (R)) during a 1-day transversal study by collecting 50 samples in seven hub stations and two trains for each of the four Metro lines. Then, during a longitudinal study, one sample was collected twice daily for 30 consecutive days in the busiest and most congested hub station. All swabs were incubated in enrichment medium for 24 h and then each suspension was plated onto a chromogenic selective medium for MRSA. After 24 h at 36 degrees C, all presumptive MRSA colonies were tested using VITEK (R) MS to confirm identification as S. aureus as well as by Alere (TM) PBP2a Culture Colony Test and mecA/mecC PCR to check methicillin resistance. Of the 110 swabs tested, 24 presumptive MRSA colonies were isolated, of which 2 were confirmed as S. aureus by VITEK (R) MS. These two isolates were tested negative using the PBP2a Culture Colony Test and PCR. Unlike other foreign cities such as Lisbon, the current data suggest a low level of MRSA contamination of hand-touched surfaces on Lyon's Metro. This should be put in perspective with the low level of MRSA colonisation in the French community. (C) 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.