Risk factors and clinical impact of levofloxacin or cefazolin nonsusceptibility or ESBL production among uropathogens in adults with community-onset urinary tract infections

Abstract

Background: Gram-negative bacilli causing community-onset urinary tract infections (CoUTIs) are getting increasingly resistant to antimicrobial agents. Clinical significance and risk factors of the acquisition of antimicrobial-nonsusceptible pathogens are still under investigation.

Methods: A prospective study was performed in the medical wards of two hospitals in southern Taiwan between August 2009 and January 2012. Patients were enrolled if they were aged >18, admitted through the emergency department, and had CoUTI due to Enterobacteriaceae isolates.

Results: Overall 136 adults with CoUTI were enrolled. Their mean age was 67 years and females were predominant (68.4%). Comorbidities, such as diabetes mellitus (30.1%) and hypertension (54.4%), were common. Escherichia coli (111, 81.6%) was the predominant species, followed by Klebsiella pneumoniae (11, 8.1%), and Proteus mirabilis (7, 5.1%). Nine (8.0%) of E. coli isolates and 5 (45%) of K. pneumoniae isolates had extended-spectrum β-lactamase (ESBL) production. Out of 122 non-ESBL producing isolates, 35 (28.7%) and 31 (25.4%) were nonsusceptible to levofloxacin and cefazolin, respectively. In the multivariate analysis, several clinical characters were found to be independently associated with CoUTIs due to levofloxacin-nonsusceptible (i.e. males, recent hospitalization, underlying old stroke, diabetes mellitus, and altered consciousness, or absence of chills, pyuria, or tachycardia), cefazolin-nonsusceptible (i.e. males, recent hospitalization, underlying old stroke, absence of fever or chills), or ESBL-producing isolates (i.e. recent hospitalization or antimicrobial therapy). All patients survived and discharged. However, the patients with CoUTIs due to levofloxacin-nonsusceptible (16.1 vs. 7.5 days, p < 0.01), cefazolin-nonsusceptible (15.4 vs. 8.4 days, p < 0.01) or ESBL-producing (16.7 vs. 9.6 days; p < 0.01) pathogens had a longer hospitalization stay than those due to their susceptible comparators.

Conclusion: Several host factors were recognized to be independently associated with the acquisition of UTIs due to levofloxacin- or cefazolin- nonsusceptible, or ESBL-producing Gram-negative bacilli. The clinical impact of UTIs due to nonsusceptible uropathogens is that they result in the prolongation of hospital stays.

Keywords: Cefazolin; Clinical impact; Extended-spectrum β-lactamase; Levofloxacin; Nonsusceptibility; Urinary tract infection.