MOLECULAR CHARACTERIZATION OF ANTIBIOTICS RESISTANCE GENES OF ENTEROCOCCI ISOLATED FROM RAW MILK IN ASSIUT CITY

Abstract

Enterococcus species are Gram-positive cocci that are characterized by being catalase-negative, facultative anaerobic bacteria, and non-spore forming. Enteroccoi is often isolated from environmental and animal sources and inhabits the human gastrointestinal tract. Enterococcus species, which gets its resources from the dairy industry, animals, and people, is one of the most abundant lactic acid bacteria in raw milk. The aim of the present study is to detect antibiotic resistance of Enterococci isolated from raw milk by phenotypic and genotypic methods. Vitek 2 Compact System was used to identify the samples and assess their antimicrobial susceptibility. Following that, drug resistance genes ( ermB , aph (3')-IIIa , and TetM ) and one virulence gene ( esp ) were molecularly detected by PCR. Twenty isolates of Enterococci were phenotypically identified by routine laboratory examination and Vitek2. High rates of antibiotic resistance were found to erythromycin and tetracycline with percentages of 65% and 35%, respectively. The presence of tetM and ermB in milk isolates was found to be 100%, similarly. No detection of aph (3′)IIIa was found in milk isolates. Esp was detected only in 5% of isolated samples. The prevalence of Enterococci among studied samples was 11.8% (20/170). The fact that Enterococci were resistant to erythromycin and tetracycline in our study was noteworthy since these bacteria could potentially be transmitted to people by drinking milk that has not been properly treated.