Plasmid-mediated fluoroquinolone resistance determinants in Escherichia coli from community uncomplicated urinary tract infection in an area of high prevalence of quinolone resistance

Abstract

In Italy fluoroquinolones (FQs) are extensively prescribed in empirical therapy of uncomplicated urinary tract infection (UTI) despite recommendations in national guidelines and widespread antibiotic resistance in community. To survey the dissemination of plasmid-mediated quinolone resistance in a peak area of FQs consumption, E. coli strains from 154 community and 41 local hospital patients were collected; low level ciprofloxacin resistance qnrA, qnrB, qnrS, and aac(6)'-Ib-cr genes were screened by PCR and patterns of transferable resistances were determined. Clinical ciprofloxacin resistance in hospital doubled community value, while overall rates of FQ resistance genes were similar (31.6% and 27.8%). Prevalence of aac(6')-Ib-cr gene was 11% in outpatients (21%, inpatients) and risk of harbouring this variant was significantly associated with gentamicin resistance; linkage to ceftazidime resistance was significant (P=0.001) and six out of eight strains produced CTX-M-15 and TEM-1 beta lactamases. In transconjugants, the unique pattern ampicillin/kanamycin-gentamicin/ ESBL + was associated with aac(6')-Ib-cr gene presence and with an increase of ciprofloxacin MIC value. Data highlight the need to monitor the resistance risk factors in the local community to provide clinicians with well-grounded guidelines for UTI therapy.

Plasmidic qnr Genes Confer Clinical Resistance to Ciprofloxacin under Urinary Tract Physiological Conditions

“…The prevalence of qnr genes in clinical urinary isolates has ranged from 10.81% to 31.6% (19,20). This prevalence has varied depending on geographical location, patient characteristics (e.g., higher prevalence in inpatients than outpatients [20]), and associated susceptibility patterns (21,22).…”

“…This prevalence has varied depending on geographical location, patient characteristics (e.g., higher prevalence in inpatients than outpatients [20]), and associated susceptibility patterns (21,22). However, the causes of this moderately high prevalence among UTI isolates remain puzzling, as Qnr determinants confer only a slight increase in resistance (below the clinical breakpoint) that should not be enough to withstand the extremely high quinolone concentrations attained in the urinary tract.…”

Characterization of Plasmid-Mediated Quinolone Resistance Determinants in High-Level Quinolone-ResistantEnterobacteriaceaeIsolates from the Community: First Report ofqnrDGene in Algeria

“…Similar rates have been described in Italy of 154 isolates of community-acquired E. coli from uncomplicated urinary tract infections, where the rate of AAC(6¢)-Ib-cr was 11%. 30 In addition, AAC(6¢)-Ibcr was the most prevalent PMQR determinant in our study, associated with the QnrB determinant in three isolates, and was described in a variety of Enterobacteriaceae species, but most frequently in E. coli (eight E. coli, two K. pneumoniae, and one M. morganii).…”

Quinolone Susceptibility and Detection of qnr and aac (6’)-Ib-cr Genes in Community Isolates of Klebsiella pneumoniae

“…In a study conducted on Escherichia coli in Italy, the rate of qnr gene carriage was 27.8% of which; aac (6')- Ib-cr was detected in 11% of the community isolates (20). In another study conducted in northern Italy between 2004 and 2006, the aac (6')- Ib-cr gene was found in 3.9% of the community isolates of the uropathogenic E. coli (21).…”