Antimicrobial Resistance in Class 1 Integron-Positive Shiga Toxin-Producing Escherichia coli Isolated from Cattle, Pigs, Food and Farm Environment

COLELLO, ROCÍO; KRÜGER, ALEJANDRA; DI CONZA, JOSÉ; ROSSEN, JOHN; FRIEDRICH, ALEXANDER; GUTKIND, GABRIEL; ETCHEVERRÍA, ANALÍA; PADOLA, NORA

Microorganisms

MedCrave

Lugar: Basel; Año: 2018 vol. 6

The aim of this study was to investigate the presence of class 1 integrons in a collectionof Shiga toxin-producing Escherichia coli (STEC) from different origins and to characterize phenoandgenotypically the antimicrobial resistance associated to them. A collection of 649 isolates werescreened for the class 1 integrase gene (intI1) by Polymerase chain reaction The variable region ofclass 1 integrons was amplified and sequenced. Positive strains were evaluated for the presenceof antimicrobial resistance genes with microarray and for antimicrobial susceptibility by the diskdiffusion method. Seven out of 649 STEC strains some to serogroups, O26, O103 and O130 isolatedfrom cattle, chicken burger, farm environment and pigs were identified as positive for intl1. Differentarrangements of gene cassettes were detected in the variable region of class 1 integron: dfrA16,aadA23 and dfrA1-aadA1. In almost all strains, phenotypic resistance to streptomycin, tetracycline,trimethoprim/sulfamethoxazole, and sulfisoxazole was observed. Microarray analyses showed thatmost of the isolates carried four or more antimicrobial resistance markers and STEC strains werecategorized as Multridrug-resistant. Although antimicrobials are not usually used in the treatmentof STEC infections, the presence of Multridrug-resistant in isolates collected from farm and foodrepresents a risk for animal and human health.