Risk factors for ciprofloxacin resistance among ESBL-producing Escherichia coli isolated from non-hospitalised patients in Spain

Abstract number: 1733_846

Alcalá J., Rodríguez-Baño J., Cisneros J., Llanos C., Cantón R., Grill F., Navarro G., Cuenca M., Peña C., Esteve M., Oliver A., Mirelis B., Almela M., Tórtola T., Pascual for the Red Española de Investigación en Patología Infecciosa A.

Objectives: ESBL production is frequently associated with quinolone (QUIN) resistance. We studied the risk factors associated with ciprofloxacin (CIP) resistance among ESBLEC isolated from non-hospitalised patients in Spain.

Methods: A double case-control study performed in 11 centres in Spain. Cases: non-hospitalised patients with isolation of ESBLEC in a clinical sample. Controls: 2 per case, non-hospitalised patients without ESBLEC. Variables analysed: demographics, comorbidities, healthcare relation and previous antimicrobials. Susceptibility was assessed by microdilution (NCCLS). ESBL were characterised by isoelectric focusing, PCR and sequencing.

Results: We included 121 cases. In 78 cases (68%) ESBLEC strains were resistant to CIP (MIC50 = 4 mg/mL, MIC90 = 64 mg/mL). Resistance to CIP was higher among strains also resistant to co-amoxiclav (AMC) (89% vs 60%, p = 0.001), co-trimoxazol (SXT) (80% vs 50%, p = 0.001), gentamicin (GNT) (85% vs 65%, p = 0.06) and tobramycin (TOB) (92% vs 65%, p = 0.04). Resistance to CIP was more frequent among patients with renal insufficiency (100% vs 65%, p = 0.012). No significant differences were found with respect to previous antimicrobial use, including QUIN, or with the type of ESBL produced. When compared to controls, the following risk factors (OR, 95% CI) for CIP-resistant ESBLEC were found: female gender (2.32, 1.30–4.16), renal insufficiency (3.12, 1.30–7.49), diabetes mellitus (5.52, 2.80–10.87), recurrent UTI (7.88, 4.43–14.02), healthcare relation (2.11, 1.24–3.58), urinary catheterisation (5.11, 2.12–12.29), previous use of QUIN (5.79, 3.15–10.64) and previous use of AMC (7.97, 3.66–17.36). Risk factors for CIP-susceptible ESBLEC were: recurrent UTI (4.15, 1.09–9.08), previous use of QUIN (4.73, 2.09–10.71) and previous use of AMC (5.44, 1.95–15.22).

Conclusions: Resistance to CIP among ESBLEC from non-hospitalised patients is associated with resistance to other antimicrobial agents, such as AMC, SXT, GNT and TOB. There is association with renal insufficiency but no association with any other variable, including previous use of QUIN. Previous use of antimicrobial agents and recurrent UTI are risk factors for both CIP-resistant and CIP-susceptible ESBLEC; and female sex, diabetes mellitus, renal insufficiency, healthcare relation and urinary catheterisation are risk factors just for CIP-resistant ESBLEC. More studies on the epidemiology of this organism are needed to identify factors related to quinolone resistance.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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