Antimicrobial resistance in Escherechia coli from pet and stray dog of La Plata, Argentina

BUCHAMER, ANDREA; BORJA, CESAR; GORTARI, LIHUEL; ROBERTO, BELEN; BULDAIN, DANIEL; CHIRINO TREJO, MANUEL; MARCHETTI, MARÍA LAURA; MESTORINO, NORA

Congreso; 14th International Congress of the European Association for Veterinary Pharmacology and Toxicology; 2018

Introduction: Bacterial antimicrobial resistance is a very seriousproblem worldwide. Mechanisms of resistance have been describedfor almost all known antimicrobials. Genetic elements involved inantibiotic resistance may be transferred among intestinal microorganisms.Escherichia coli represents among intestinal microbiome ofhuman and animals the group that can play a role of indicator bacteria,with great potential for harbouring and transferring of resistance.The surveillance of its resistance is an important tool in thecontrol of non-prudentuse of antimicrobials. The objective of thisresearch was to evaluate in vitro E. coli resistance in strains isolatedfrom pet and stray dogs of La Plata city, Buenos Aires, Argentina tocompare their resistance profiles.Materials and Methods: Samples were collected from 50 dogs withowners (home dogs = HD) and 50 homeless dogs (stray dogs = SD).Strains were isolated from dog faeces using rectal swabs. Faecalsamples were cultured in 3 plates with MacConkey agar: with0.05 mg ml−1 of ciprofloxacin (plate A), with 2 mg ml−1 of cefotaxime(plate B) and without antimicrobials (plate C). Strains that grew onplate A and/or B, and those which developed only in plate C, werechosen to determine the antimicrobial susceptibility by antibiogram.Strains were stained by Gram and typified by biochemical tests. Thestandard Kirby-Bauerdisk diffusion method was used to determinethe antimicrobial susceptibility profiles for 20 antimicrobial agentsused in human and veterinary medicine. Isolations were classifiedas resistant, intermediate or susceptible (CLSI 2013). E. coli ATCC25922 was used for quality control.Results and Conclusions: 47 strains of HD and 50 ones of SD wereselected to study. The most common resistance observed wasto tetracycline (70% SD ? 27.7% HD), ampicillin (44% SD ? 25.5%HD). Streptomycin resistance was high in SD strains (46%), andsulphamethoxazole trimethoprim resistance (19.1%) in HD. In bothgroups the level of resistance to 3rd generation cephalosporins washigh (ceftriaxone: 30% SD ? 21.3% HD and cefotaxime: 28% SD).There was higher level of antimicrobial resistance in strains fromSD compare to HD. No E. coli from either group showed resistanceto imipenem or nitrofurantoin. There were multiresistant strains inboth groups and their resistance profile includes one, two, three andmore than four antimicrobials. Multiresistance occurrence was considerablyhigher in SD strains, with 42% of multiresistance to morethan 4 antimicrobials. These levels of resistant are higher than previouslypublished in Argentina and other countries (1,2). Knowing theprevalence of resistance in companion animals is of extreme importancefor public health all over the world.