OBJECTIVETo explore the diversity changes of microbial communities and bla(CTX-M) in an urban river sediment community with cefotaxime treatment.

METHODSThe terminal restriction fragment length polymorphism (T-RFLP) of 16S rDNA was employed to analyze the bacteria community, and the bla(CTX-M) was determined using nested PCR. The sediment was treated by cefotaxime at the concentrations of 0, 6.4, 64, and 320 mg/L.

RESULTSAccording to statistical analysis of the T-RFs, no significant correlation was observed between the antibiotic treatment and the microbial community change, but incubation in laboratory conditions had significant effect on the microbial diversity. The PCR results showed that the diversity of bla(CTX-M) decreased after the laboratory incubation.

CONCLUSIONAs there are diverse antibiotic resistant bacteria in the sediments with prior pollution by antibiotics, the whole community can be inert to the antibiotic treatment. Nevertheless, the ex situ treatment conditions in laboratory studies have a significant impact on the community structures.