AN INVESTIGATION OF THE RELATIONSHIP BETWEEN THE LEVEL OF ANTIBIOTIC RESISTANCE OF ESCHERICHIA COLI IN NONTIDAL WETLANDS AND COMMON WETLAND HEALTH FACTORS

Abstract

This report investigated the prevalence of antibiotic resistance among Escherichia coli in the water of 13 non-tidal mitigation wetlands in Maryland, and its relation to land use and wetland health. At each site, land use, surface and sub-surface water samples, soil samples, and vegetation cover were collected. From the water samples, individual colonies of E. coli were isolated and tested, using the disc diffusion method, for resistance to the antibiotics ampicillin, ciprofloxacin, erythromycin, sulfisoxazole, and tetracycline. According to soils, vegetation and water quality improvement criteria the wetlands function like healthy wetlands. The wetlands' E. coli exhibit resistance to all of the antibiotics tested, except for ciprofloxacin. There were statistically significant relationships found between land use and antibiotic resistance, vegetation, soil and water chemistry. Surprisingly, E. coli in wetlands with smaller stocks of carbon and nitrogen in their soil exhibited more resistance to tetracycline, possibly indicating that soil quality plays an important role in fostering or fighting antibiotic resistance. The work demonstrates that antibiotic resistance is present in Maryland's wetlands, but that its spread could be subdued by healthy wetlands.