Methicillin-resistant Staphylococcus aureus (MRSA) in municipal wastewater : An uncharted threat?

• Methicillin-resistant S. aureus (MRSA) was recently detected in municipal wastewater, why there is a need for further studies to elucidate if MRSA in wastewater constitutes a health risk, and to determine how wastewater treatment processes affects MRSA. We cultivated MRSA from a full-scale wastewater treatment plant to characterise the indigenous MRSA-flora and to investigate how the wastewater treatment process affects the clonal distribution. MRSA isolates were characterised using spa typing, antibiograms, SSCmec typing and detection of Panton Valentine leukocidin (PVL) genes. We found that the wastewater MRSA-flora has a close genetic relationship to clinical isolates, but we also isolated novel spa types, primarily from the activated sludge treatment step. The number of isolates and the diversity of MRSA are reduced by the treatment process, but the process also selects for more extensive antibiotic resistant strains as well as for PVL positive strains.

Nyckelord

Staphylococcus aureus

MRSA

methicillin

β-lactam

SCCmec

spa typing

Panton Valentine leukocidin

PVL

antibiotic resistance

antibiogram

MEDICINE

MEDICIN

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)