Analysis of drug resistance and β-lactamase production of proteus mirabilis isolated from urine samples

Objective To analyze the drug resistance and extended spectrum β-lactamases (ESBLs) of proteus mirabilis isolates from urine samples. Methods Thirty-one proteus mirabilis strains of urine samples were collected. The identification and the minimum inhibitory concentration (MICs) were determined by PhoenixTM-100; ESBLs was analyzed by double-disk synergy test. The ESBLs genotype of TEM, SHV, CTX-M, ACC, FOX, OXA, MOX, DHA, CMY1-23, ACT-1 and MIR were performed by PCR. pulsed-field gel electrophoresis (PFGE) was performed to analyze the homology of those isolates. Results The sensitive rates of imipenem and meropenem against proteus mirabilis were 100%, and piperacillin/tazobactam, cefoxitin, amoxicillin/clavulanic acid, ceftazidime, amikacin were recorded to be 98.59%, 97.18%, 94.37%, 88.73%, 85.92%, respectively. The susceptibility rate to nitrofurantoin, sulfamethoxazole, ampicillin, ciprofloxacin were all less than 50.00%. Six isolates of proteus mirabilis produced ESBLs, and they were all resisitant to ceftazidime and cefotaxime. Among these isolates, four isolates produced ACC-1-type AmpC beta-lactamases, three isolates produced CTX-M-1-type ESBLs, two isolates produced CTX-M-14-type ESBLs. Three strains of proteus mirabilis producing both CTX-M-1 and ACC-1 had typical correlations. Conclusions Some proteus mirabilis isolates from urine samples in hospital were resistant to ceftazidime and cefotaxime by encoding CTX-M-type ESBLs and/or ACC-1-type AmpC beta-lactamases. The results suggest that there exists cloning spread between different strains. So it is very important to use antibiotics reasonably and to prevent and control the multidrug-resistant bacteria in hospital. Key words: Proteus mirabilis; Drug resistance; Extended spectrum β-lactamases