Plasmid-Mediated Antibiotic Resistance and Class 1 Integron in Salmonella Heidelberg Isolated from Poultry Farms in Santander - Colombia

ABSTRACT

Salmonella enterica is a zoonotic pathogen transmitted to humans by the consumption of contaminated poultry products. Salmonella causes around 93 million cases of gastroenteritis and 155,000 deaths worldwide. A high number of multidrug-resistant Salmonella isolates has been found from different segments of poultry production, and it is often associated with horizontal antibiotic resistance gene transfer through mobile elements such as plasmids, integrons, and transposons. The emergence of antibiotic-resistant Salmonella has been associated with the misuse of antibiotics in animal production and it is classified as a highly important pathogen from public health due to its zoonotic character and its high dissemination ability. This study aimed to determine the antibiotic resistance associated with plasmids, and class 1 and 2 integrons from Salmonella Heidelberg isolates from healthy chickens in poultry farms from Santander, Colombia. 15 Salmonella Heidelberg isolates obtained from cloacal samples, were evaluated through endpoint PCR to determine the presence of plasmid-encoded resistance genes, and class 1 and 2 integrons. The bla CMY2 , strA and strB, sul1 and sul2, and tetB genes were found in all 15 Salmonella Heidelberg. The class 1 integron was present in 11 out of 15 isolates, harbored the gene cassette dfra7.The results indicate the presence of a high number of antibiotic resistance genes associated with plasmids and class 1 integrons in Salmonella Heidelberg strains isolated from poultry farms, resulting in a public health concern, both in humans and poultry production in Colombia.