98 Evaluation of bacteria antibiotic resistance in wastewater sludge from hospitals

In hospital wastewater treatment plants, some bacteria and heavy metals are accumulated by direct or indirect sedimentation, which may influence the characteristics of bacteria antibiotic resistance. In the research, three kinds of hospital wastewater sludges were collected for subsequently analysis. A BD Phoenix-100 automated interpretation system was used to identify the bacteria species and antibiotic resistance. The metal compositions were analyzed by using ICP-OES. The results showed that most of the identified bacteria were gram positive coccus, i.e., Streptococcus agalactiae, Enterococcus faecalis, and Staphylococcus hominis. The sludge was found to contain high concentration of metals and most of them exceeded the national Water Quality Standards, for instance: Aluminum was averaged 4300 (mg/kg), Chromium 25 (mg/kg), Copper 70(mg/kg), Iron 6140(mg/kg), Nickel 16(mg/kg), Lead 29(mg/kg), and Zinc 618(mg/kg). Bacillus cereus was found to resist antibiotic agents such as AM, FOX, and P; Streptococcus agalactiae was found to resist to FA and GM; Enterococcus faecalis was found to resist to FOX, CC, FA, GM, P, QDA, and SXT; Staphylococcus hominis was found to resist to AM, FOX, OX, P, and SXT. Bacteria increase antibiotic resistance through cross-resistance or co-resistance mechanisms when encountered the environmental stress. From previous studies, when bacteria expose to excessive concentrations of heavy metals will stimulate the bacteria mutation and force bacteria to alter their genetic to survive, contributing to an increase the antibiotics resistance. Employees who work in wastewater treatment plants are recommended to wear respirators to avoid exposure to suspended sludge aerosols.