Comparative Study on Antibiotic Resistance of Thermotolerant Escherichia coli in Sewage from a Hospital and Residential Areas in Shanghai

Objective To compare the resistance of thermotolerant Escherichia coli against seven common antibiotics in hospital and living sewage, and to identify the sources of antibiotic resistant microorganisms in environment.

Methods Samples of sewage from a hospital and adjacent residential living areas were collected and followed by isolation and culture of thermotolerant Escherichia coli. Kirby-Bauer test was used to detect the resistance against seven common antibiotics, and statistical analysis was performed for the detection results.

Results In the 272 thermotolerant Escherichia coli colonies established from living sewage, the detection rates of antibiotic resistance against amoxicillin, aztreonam, ceftazidime, cefoperazone, cefotaxime, cefepime, and cefoxitin were 76.84%, 38.97%, 45.86%, 20.59%, 41.91%, 34.19%, and 39.71%, while these detection rates in 182 thermotolerant Escherichia coli colonies established from hospital sewage were 87.91%, 80.22%, 81.32%, 78.02%, 62.64%, 85.16%, and 82.42% respectively. The differences were statistically significant (all Ps<0.05).

Conclusion Different proportions of thermotolerant Escherichia coli with antibiotic resistance are identified in the hospital and living sewage; hospital sewage might contribute more than living sewage to environmental antibiotic resistant microbial contamination.