In vitro Susceptibility to Antibiotics of Escherichia coli Isolates in Community Acquired Urinary Tract Infections

Z. Barišić, A. Babić-Erceg, E. Borzić, M. Carev, V. Kaliterna, V. Zoranić, M. Smoljanović

Public Health Institute, Split, Croatia

Objectives: To determine in vitro susceptibility of E. coli isolates in community acquired urinary tract infections (CA-UTI) and to suggest optimal empirical antibiotic therapy in these patients.

Methods: Three hundred fifthy seven consecutive strains of E. coli isolated from patients with CA-UTI were included in this study. Isolation and identification were performed by standard method and susceptibillity testing was performed by disk diffusion method. Susceptibillity was tested to amoxycillin (AMX), amoxycillin-clavulanate (AMC), cephalexin (CN), cefuroxime (CXM), ceftibuten (CTB), trimethoprim-sulfamethoxazole (STX) and ciprofloxacin (CIP).

Results: From total number of 357 strains of E. coli 44,32 % were resistant to AMX, 3,92 % to AMC, 4,76 % to CN, 2,24 % to CXM, 0,84 % to CTB, 17,09 % to STX and 1,77 % strains were resistant to CIP.

Conclusions: The best in vitro susceptibillity was shown for ceftibuten, followed by ciprofloxacin and cefuroxime. Strains of E. coli show high resistance rate to trimethoprim-sulfamethoxazole and amoxycillin.
The antibiotic of the best choice for empirical antibiotic therapy in patients with CA-UTI in our region is ceftibuten. Drugs like trimethoprim-sulphametoxazol or amoxycillin, most often prescribed in empirical therapy of CA-UTI, are not a good choice, because strains of E. coli show high rate of in vitro resistance to these antibiotics.