title: Self-transmissible antibiotic resistance to ampicillin, streptomycin, and tetracyclin found in Escherichia coli isolates from contaminated drinking water.
abstract: Presence and survival of cultivable bacteria in drinking water can act as a vehicle to disseminate virulence genes (adherence, enterotoxigenic and antibiotic resistance) to other bacteria. This can result in high morbidity and mortality, and the failure of the treatment of life threatening bacterial infections in humans and animals. In this study, antibiotic resistance (ABR) patterns and transferability of the ABR markers was investigated in Escherichia coli isolates obtained from drinking water and human urine samples. The ABR in E. coli isolates was determined against 15 antibiotics commonly used in human and veterinary medicine. A high frequency of ABR to carbenicillin (56%), tetracycline (53%) and streptomycin (49%) and a low frequency of cefizoxime (5%), amikacin (8%), cefazidine, (5%), chloramphenicol (9%), and kanamycin (18%) was found in the tested E. coli isolates. ABR to kanamycin (0% vs. 35%) and moxalactam (4% vs. 30%) was higher in drinking water isolates whereas resistance to streptomycin (92% vs. 15%), ampicillin (24% vs. 10%), and nalidixic acid (12% vs. 0%) was higher in human urine isolates. A large number of E. coli isolates (93%) exhibited resistance to two or more antibiotics. Two of E. coli isolates from drinking water showed resistances to six (Cb Cm Cx Ip Mx Tc and An Cb Km Mx Sm Tc) and one was resistant to seven antibiotics (Am An Cb Km Mx Sm Tc). A majority of the multiple antibiotic resistant E. coli isolates contained one or more plasmids (size ranged approximately 1.4 Kb to approximately 40 Kb). The ABR traits (Am and Tc) were transferable to other bacteria via conjugation. These data raise an important question about the impact of E. coli containing self-transmissible R-plasmids as a potential reservoir of virulence genes in drinking water.
authors.affiliation: Department of Biological Sciences, Oakland University, Rochester, Michigan 48309, USA. walia@Oakland.edu
authors.forename: Satish K
authors.initials: SK
authors.lastname: Walia
authors.forename: Alan
authors.initials: A
authors.lastname: Kaiser
authors.forename: Mohinder
authors.initials: M
authors.lastname: Parkash
authors.forename: G Rasul
authors.initials: GR
authors.lastname: Chaudhry
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000668:Ampicillin Resistance; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000032:analysis; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects*; D006801:Humans; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000187:drug effects; D013307:Streptomycin / Q000494:pharmacology; D013752:Tetracycline / Q000494:pharmacology; D013753:Tetracycline Resistance; D014556:Urine / Q000382:microbiology; D014871:Water Microbiology; D014873:Water Pollutants; D014881:Water Supply
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D014873:Water Pollutants; D000667:Ampicillin; D013752:Tetracycline; D013307:Streptomycin