Multidrug resistance in Escherichia coli carrying integrons isolated from a pig farm with moderate antibiotic use

DE LA TORRE, EULALIA; COLELLO, ROCÍO; FERNÁNDEZ, DANIEL; ETCHEVERRÍA, ANALÍA I.; DICONZA, JOSÉ; GUTKIND, GABRIEL; TAPIA,MARÍA OFELIA; DIEGUEZ, SUSANA; SORACI, ALEJANDRO LUIS; PADOLA, NORA L.

JOURNAL OF GENERAL AND APPLIED MICROBIOLOGY

MICROBIOL RES FOUNDATION

Año: 2015 vol. 61 p. 270 - 273

0022-1260

The emergence and dissemination of antimicrobial resistant in bacteria derived from food-produci30 ng31 animals is a consequence of intensive agricultural and veterinary use of antimicrobial compounds.32 Inappropriate use and prescribing of antibiotics, along with their use as growth promoters, is the main33 cause of development of resistance. The potential risk of transfer of this resistance through the food chain34 by bacteria as Escherichia coli (E. coli), including food borne pathogens such as Shiga toxin-producing E.35 coli implies a problem for public health (van den Bogaard & Stobberingh, 2000). Horizontal gene transfer36 is an important route of the dissemination. Integrons are genetic elements able to capture gene cassettes37 encoding antibiotic resistance from the environment and incorporate them by site-specific recombination.38 Integrons are gene-capture and expression systems characterized by the presence of an intI gene39 encoding an integrase, a recombination site (attI), and a promoter. The most frequently reported mobile40 integrons are class 1 and class 2 integrons, which have been shown to contribute to the spread of41 antimicrobial resistance genes. It is important to remark that the presence of integrase is potentially42 indicative of strains capable of recruiting antibiotic resistance genes (Cambray et al., 2010). Moreover,43 resistance genes and resistant bacteria in the environment are considered an ecological problem.44 Thereby, investigation of commensal bacteria is important in order to assess the extent of the drug45 resistance problem. The aim of the present study was to evaluate the susceptibility to antibiotics in46 commensal integron-positive E. coli isolated from pigs from a pig farm in Argentina.47 Samples were taken from a commercial farm in Buenos Aires Province, Argentina, between March and48 June 2012. The use of antibiotic in the farm was considered moderate because sub therapeutic feed49based antibiotics were not used, and only therapeutic concentrations of tetracyclines were used for short50 period during disease outbreaks. In addition, injectable antibiotics (fosfomycin, tiamulin, amoxicillin) were51 not used except for brief periods to control atypical disease outbreaks (less than 15 days per year).