[Antimicrobial susceptibility of Proteus mirabilis urinary tract isolates from 1999 to 2005 at Nîmes University Hospital].

AIM OF THE STUDY: To analyse antimicrobial resistance trends of Proteus mirabilis urinary tract isolates from 1999 to 2005 at the Nîmes University hospital.

MATERIALS AND

METHODS

We retrospectively collected non-duplicate urinary tract infections and colonization isolates from inpatients between 1 January 1999 and 31 December 2005.

RESULTS

One thousand and eight non-duplicate urinary tract isolates were studied, 63.1% were from females and the mean age was 76 years. The mean resistance rate was 59.0% for amoxicillin (AMX), 48.0% for piperacillin (PIP), 3.9% for cefotaxim, 33.9% for amoxicillin plus clavulanic acid (AMC) and 2.8% for piperacillin plus tazobactam (TZP). A significant increase in resistance was observed for AMC and TZP. The mean resistance rate was 35.0% for norfloxacin, 34.8% for ofloxacin and 23.5% for ciprofloxacin. No significant increase in resistance to fluoroquinolones was seen except for ciprofloxacin whereas a significant increase was observed for aminoglycosides. The mean rate resistance for cotrimoxazole was 33.2% with a significant decrease in the resistance during the study period.

CONCLUSION

P. mirabilis stilled sensitive to cefotaxim or ceftazidim and to TZP. The significant increase in the rate resistance to AMC and TZP could be explained by production of beta-lactamases and in particular extended-spectrum beta-lactamases. The increase in resistance observed for fluoroquinolones become a major concern. Amikacine was the most active aminoglycosides. These data suggested for the re-enforcement of the antimicrobial susceptibility surveillance in order to optimise the rational use of antibiotics.