Antimicrobial resistance of Esherichia coli urinary isolates from primary care patients in Greece.

Background: Most of antimicrobial susceptibility surveillance studies focus on isolates from hospitalized patients. A retrospective analysis of microbiological data of the antimicrobial susceptibility of Escherichia coli urinary isolates from primary care patients in Greece was performed here.

Material/methods: The in vitro susceptibility to ampicillin, amoxicillin/clavulanate, cefaclor, cefprozil, trimethoprim-sulfamethoxazole (cotrimoxazole), amikacin, and norfloxacin of 2460 E. coli isolates (01/2005-06/2005) from the urine specimens of patients tested at the laboratories of three Greek primary care diagnostic centers were analyzed. Only the first isolate per patient (2074 females and 386 males) were included in the analysis.

Results: The proportion of E. coli urinary isolates that were resistant to cotrimoxazole was 20.8% and 26.4% for females and males, respectively. There were noteworthy differences between age groups; 37.8% isolates from females <15 years old were resistant to cotrimoxazole compared with 18.9%, 17%, and 23.3% for the 15-35, 35-45, and >55-year-old females, respectively (P<0.001). The proportion of isolates resistant to ampicillin was very high (from 32.1% to 45.3% and 38% to 63% for the urinary isolates from females and males, respectively, in the different age groups examined), while it was relatively low for amikacin (up to 4.1%); 17.8% and 5.5% of the isolates from males and females, respectively, were resistant to norfloxacin (18.2% for males >55 years old).

Conclusions: These findings offer help to clinicians in deciding the appropriate empirical treatment for primary care patients with urinary tract infection and emphasize the increasing problem of antimicrobial resistance even in the primary care setting in Greece.