Sunday, August 12, 2012
Columbia Hall, Terrace Level (Washington Hilton)
The purpose of this study was to assess the presence of multidrug resistant (MDR) heterotrophic bacteria in anthropogenic chemicals contaminated urban river sediments and industrial sites. Pharmaceutical and personal care products (PPCP) and PCB contaminated river sediments, soil and groundwater samples collected from the Detroit area in MI and in Syracuse, NY were studied for the presence of MDR opportunistic bacterial pathogens, which also have PCB- degrading capabilities. The PCB-degrading bacteria from the soil-groundwater system demonstrated 100 % biotransformation of 3,5-dichlorobiphenyl and up to 54% biotransformation of 2,2’,3,3’5,6,6’-heptachlorobiphenyl. Known opportunistic pathogens were identified in all of the river sediment and soil-water samples tested. The antibiotic susceptibility assays were performed on bacterial isolates against 8 antibiotics. The results showed that the PCB-degrading bacteria were resistant to six clinically effective antibiotic classes: cephalosporins, carbapenems, quinolones, aminoglycosides, chloramphenicol and tetracycline. Thirteen out of 17 (76%) PCB-degrading bacteria were found to be resistant to a combination of 3 or more antibiotics. The urban river sediment contained CTX-M-type extended-spectrum beta-lactamase genes. The findings from this study indicate that MDR bacteria are not only prevalent in clinical bacteria, but they are also present in river sediments, soil and groundwater at urban and industrial sites, which are contaminated with anthropogenic chemicals. The environmental implication is significant, in that risk assessments at PCB-contaminated sites do not consider health and environmental risks associated with the presence of MDR bacteria.