Multiresistant urinary tract isolates of Escherichia coli: is it an issue in the empiric management of acute uncomplicated cystitis?

Abstract number: P676

Katsarolis I., Poulakou G., Athanasia S., Panagopoulos P., Kontopidou F., Kremastinou J., Karaiskos E., Voutsinas D., Zarkotou L., Koratzanis G., Kanellopoulou M., Gavra P., Adamis G., Vagiakou E., Vogiatzi E., Perdikaki P., Panou C., Kalovolou L., Psychogiou M., Lambri N., Birbilis C., Kalyvas C., Daikos G., Veliotis G., Kanellakopoulou K., Giamarellou H.

Objectives: To assess the prevalence of multiresistance (multiR) among E. coli strains isolated from patients with community-acquired urinary tract infections (UTI).

Methods:Escherichia coli strains were isolated from outpatients >16 ys referred for urine culture. Resistance (%R) was defined by disk diffusion according to CLSI 2006. A questionnaire accompanied each sample, in order to differentiate acute uncomplicated cystitis cases (AUC). MultiR was defined as R to 3 or more agents among ampicillin (AMP), cephalothin (CEP), nitrofurantoin (FUR), cotrimoxazole (COT) and nalidixic acid (NAL). R to amoxicillin-clavulanate (AMC), cefuroxime axetil (CXM), mecillinam (MEC), fosfomycin (FOS) and ciprofloxacin (CIP) was also defined. Risk factors for multiR strains isolation were processed by univariate analysis and parameters with P < 0.1 were entered in a multivariate logistic regression stepwise model. Odds ratio (OR) and 95% confidence intervals (95%CI) were calculated. A P value leqslant R: less-than-or-eq, slant0.05 was considered as statistically significant.

Results: From Feb 2005-Mar 2006 and a total of 1545 E. coli strains, 731 cases of AUC were identified. %R rates in AUC were: AMP 25.5, CEP 6.7, FUR 4.6, COT 18.4, NAL 5.9, CIP 1.8, AMC 2, CXM 1.6, MEC 2.7 and FOS 0.8. Of these isolates, 6% were multiR (44/731). The predominant multiR phenotype included R to AMP-COT-NAL (12/44, 27.3%). Among multiR isolates, %R rates were: AMP 97.7, COT 77.3, CEP 63.6, NAL 61.4, FUR 31.8, CIP 22.7, CXM 22.7, AMC 20.5, MEC 9.5 and FOS 4.5. Use of fluoroquinolones in the previous 3 months (OR 3.66, 95%CI 1.82–7.37, P < 0.001) and age >65 ys (OR 2.22, 95%CI 1.46–3.39, P < 0.001) were significantly associated with multiR E. coli isolation in the multivariate analysis (model variables: UTI history, antibiotic use in the previous 3 months, hospital admission, diabetes mellitus, age).

Conclusions: Prevalence rates of E. coli urinary isolates multiR are significant and call for continuous surveillance, especially among elderly patients. For AUC empiric treatment, increased COT %R undermine its use as first-line agent. Although CIP exhibits low %R, caution in fluoroquinolone use as first-line for the empiric AUC treatment is prompted by: (a) increased NAL %R, (b) quinolone-resistant strains being frequently multiresistant, and (c) fluoroquinolone use association with multiR E. coli isolation. Mecillinam, fosfomycin and nitrofurantoin could serve as first-line choices, in the context of fluoroquinolone-sparing regimens.

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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