Abstract:

BACKGROUND: Implantation of biomaterials can induce infection, resulting in implant loosening, shedding, even bacteremia. Previous studies do not focus on bacterial drug resistance in implant-related infection.
OBJECTIVE: To investigate the resistance characteristics of implant infection-associated Escherichia coli to provide strategies for prevention and treatment of this infection.
METHODS: With E.coli ATCC 25922, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 as quality control strain, 17 commonly used antibiotics were selected to perform susceptibility test. The resistance rates were calculated to analyze resistance characteristics; disc screen test and disc diffusion phenotypic confirmatory test were used to detect strains producing Amp C and ESBLs, a clear enzyme production rate; resistance plasmid was extracted. Drug resistance genes were detected by PCR expansion. Genotype distribution was analyzed.
RESULTS AND CONCLUSION: Of 17 antibiotics, imipenem resistance rate was the lowest, followed by amikacin, cefoperazone/sulbactam, cefepime and piperacillin/tazobactam, and most were multi-drug resistant strains. A total of 42 strains (61.8%) were screened and produced ESBLs and 27 isolates (39.7%) Amp C production strains, while producing ESBLs and Amp C strains were 23 (33.8%). ESBLs producing strains carrying CTX-M type gene were the most common accounting for 66.7%, 19 strains (45.2%) carrying two or more genes. Of producing Amp C production, the majority of strains were DHA-type, and 5 strains (18.5%) carried two genes. Implant infection of Escherichia coli strains showed high levels of resistance, resistance spectrum to expand, and multiple drug resistance. The drug resistant gene is complex and diverse. Sensitive drugs in combination with amikacin are recommended to treat this kind of infection.