Data di Pubblicazione:
2012
Citazione:
Fluoroquinolone resistance in escherichia coli isolated from poultry / P. Cagnardi, G. Dotto, L. Intorre, M. Vanni, V. Meucci, A. Piccirillo, C. Montesissa - In: Sixth International Conference on Antimicrobial Agents in Veterinary Medicine (AAVM)[s.l] : Target Conference, 2012. (( Intervento presentato al 6. convegno Sixth International Conference on Antimicrobial Agents in Veterinary Medicine tenutosi a Washington DC, USA nel 2012.
Abstract:
Escherichia coli is a common inhabitant of the intestinal tract of mammals and birds, although some strains may cause infection in poultry, i.e. colibacillosis, an important cause of economic losses for poultry industry. Fluoroquinolones (FQs) have been widely used in veterinary medicine since their introduction and the consequent selective pressure has increased the risk of emergence of resistant bacteria. Subsequently increasing resistance rate against that antimicrobial class in avian E. coli have been observed during the last decades. FQs resistance in E. coli is mainly associated with point mutations in the quinolone-resistance-determining-region (QRDR) of the gyrA/gyrB and parC/parE genes, coding for the targets of FQs action DNA gyrase and DNA topoisomerase IV, respectively.
The minimal inhibitory concentrations (MICs) of 8 FQs (ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, flumequine, marbofloxacin, nalidixic acid and sarafloxacin) were determined using the broth microdilution method in 210 E. coli strains isolated from poultry reared in intensive farms in Italy. Isolates were classified as resistant or susceptible to selected FQs in accordance with breakpoints proposed by the Comité de l’Antibiogramme-Société Française de Microbiologie (CA-SFM, Recommandations 2011); MIC50and MIC90of E. coli isolates were also determined.
The isolates resulted highly resistant to nalidixic acid (72.4%), flumequine (67.1%) and difloxacin (65.7%), while less than 20% showed resistance to ciprofloxacin and marbofloxacin. Overall, 27.6% of isolates (58 out of 210) were fully susceptible to all tested FQs, while the 21.9% of isolates (46 out of 210) were resistant to all FQs. The most prevalent resistance pattern including nalidixic acid, difloxacin and flumequine, was showed by the 43.8% of isolates (92 out of 210). Very high MIC50and MIC90 values were observed for nalidixic acid (256 and >256 mg/ml, respectively), flumequine (16/>256 mg/ml) and difloxacin (4/256 mg/ml), while lower MIC50 and MIC90 values were recorded for enrofloxacin (0.5/32 mg/ml) sarafloxacin (0.5/16 mg/ml), danofloxacin (0.25/16 mg/ml), marbofloxacin (0.25/8 mg/ml) and ciprofloxacin (0.0625/4 mg/ml), resulting still active FQs against E. coli isolates.
Tipologia IRIS:
03 - Contributo in volume
Elenco autori:
P. Cagnardi, G. Dotto, L. Intorre, M. Vanni, V. Meucci, A. Piccirillo, C. Montesissa
Link alla scheda completa:
Titolo del libro:
Sixth International Conference on Antimicrobial Agents in Veterinary Medicine (AAVM)