EVALUATION OF ANTIBIOTIC-RESISTANT BACTERIA IN TERTIARY TREATED WASTEWATER, RECLAIMED WASTEWATER USED FOR SPRAY IRRIGATION, AND RESULTING OCCUPATIONAL EXPOSURES

Abstract

Occupational exposures to vancomycin-resistant <italic>Enterococcus</italic> (VRE) and methicillin-resistant <italic>Staphylococcus aureus</italic> (MRSA) in reclaimed wastewater used for spray irrigation were evaluated. In 2009, wastewater was collected from a tertiary-treatment facility, and reclaimed wastewater, nasal and dermal swab samples from an irrigation site. Samples were evaluated for MRSA and VRE using standard methods, PCR, and susceptibility testing. MRSA and VRE were isolated from all wastewater samples except effluent. While wastewater MRSA isolates were multidrug resistant (98%), no MRSA was isolated in irrigation water or swabs. VRE was isolated in one irrigation water sample. Fewer irrigation workers were colonized with <italic>S. aureus</italic> (31%) compared to controls (46%), but they harbored more multidrug resistant <italic>S. aureus</italic>. This is the first study to 1) evaluate antibiotic-resistant bacteria (ARB) in U.S. reclaimed wastewater and resulting occupational exposures, and 2) detect MRSA in U.S. wastewater. The findings suggested that tertiary wastewater treatment effectively reduced MRSA and VRE.