Frequency of vancomycin and aminoglycoside resistance genes in Enterococcus spp. isolated from chicken raw meat samples

  Enterococci are main normal microbial flora of both humans and animals and can survive in a diverse range of environments. These bacteria carry out aminoglycoside and vancomycin resistance genes and spread them in environment by many routs such as chicken meat products. The present study was aimed to determine the frequency of aminoglycoside and vancomycin resistant genes in Enterococcus species isolated from chicken meat specimens.

  A total of 250 chicken raw meat specimens was prepared from slaughterhouses at Zanjan province, cultured at BHI broth and incubated at 37°C for 24h. The positive cultures were sub-cultured in blood agar plates and grown colonies identified using phenotypical and biochemical tests. Antibiotic susceptibility was determined according to the Clinical and Laboratory Standards Institute (CLSI) standards and PCR assays were performed to detect vanA, vanB, aph (2")1c, aph (2")1b, aph (2")1d, ant(3'), aph(3')IIIa, ant(4')1a, ant(6') and aac(6') genes.

 In total, 100 Enterococcus species isolated from 250 specimens and 35% of them belonged to E. faecalis and the others were E. faecium (65%). The prevalence of the vanA, vanB, aph (2")1c, aph (2")1b, aph (2")1d, ant(3'), aph(3')IIIa, ant(4')1a, ant(6') and aac(6') genes among the 100 Enterococcus species was 14%, 12%, 10%, 1%, 2%, 50%, 26%, 9%, 18% and 22%, respectively.

  The current study revealed that the rate of antimicrobial resistance genes to aminoglycosides and vancomycin was worrying and health measurements in meat products industries must be performed to prevent spread of antimicrobial resistance elements among bacteria.