Drug-Resistant Escherichia coli Are Abundant in Hospital Sewage

Abigail Zuger, MD

Not only that, but they also survive wastewater treatment without difficulty.

Hospitals are repositories of multidrug-resistant organisms, but hospital wastewater routinely enters general urban and suburban sewage systems, with transfer of hospital-specific organisms into the local environment.

Researchers in France tested wastewater samples for extended-spectrum β-lactamase–producing Escherichia coli (ESBLEC) at multiple points in the wastewater network of a mid-size French city (population 120,000; 2 hospitals; 1 wastewater treatment plant). The overall concentration of E. coli was about half as high in hospital wastewater as in general urban wastewater, but the concentration of ESBLEC in hospital wastewater was >30-fold higher, and individual isolates were more resistant, particularly to ceftazidime and ofloxacin.

The wastewater treatment plant eliminated 98% of all E. coli but only 94% of ESBLEC, so both water and sludge that emerged from the plant were relatively enriched for drug-resistant organisms. All told, the treatment plant released an estimated 6×1011 ESBLEC daily into the local river and produced sludge containing 2.6×105 ESBLEC per g for local use as fertilizer without further processing.

Citation(s):

Bréchet C et al. Wastewater treatment plants release large amounts of extended-spectrum β-lactamase–producing Escherichia coli into the environment. Clin Infect Dis 2014 Jun 15; 58:1658.

Griffiths JK and Barza M.What happens in hospitals should stay in hospitals. Clin Infect Dis 2014 Jun 15; 58:1666.