Distribution of Antibiotic Resistance Genes in Enterococcus spp. Isolated from Mastitis Bovine Milk

Abstract

In this study, determination of enterococcus species that were isolated from mastitic milk samples, investigation of their susceptibilities to antibiotics and identifi cation of the existence of resistance genes in resistant strains were conducted. The specimens consist of 600 mastitic milk samples that were collected from 242 cows. Isolation of enterococcus was carried out in selective media and 94 (15.6%) Enterococcus spp. were isolated. A total of 94 species of Enterococci were identifi ed using both sequencing and polymerase chain reaction (PCR). Enterococcus spp. isolates belong to 5 different species (E. faecalis, E. faecium, E. durans, E. hirae, E. mundtii) in sequence analysis and 4 different species (E. faecalis, E. faecium, E. durans, E. hirae) were identify by PCR method with specifi c primers. Analyzing 94 enterococcus strains by antibiotic sensitiveness test a high rate of resistance to tetracycline in 77 (81.9%) isolates was shown. The tet resistance genes were identifi ed as follows: 54 were tetM positive, 23 were tetK positive and 17 were positive on tetM and tetK. Resistance to erythromycin was established in 27 (28.7%) isolates (25 ermB) while the chloramphenicol resistance gene was found in 10 (10.7%) of isolates and the cat gene was identifi ed in nine samples and one isolate was resistant to vancomycin (1.06%) with the VanA gene confi rmed. In conclusion, it was shown that E. faecalis has the biggest role in enterococcus originated mastitis and these strains were found to be mostly resistant to tetracycline. One vancomycine resistant isolate that had the VanA gene was also determined.

Occurrence of enterococci in mastitic cow’s milk and their antimicrobial resistance

“…According to Erbas et al . (12), 1.1% of the isolates in Turkey showed resistance to vancomycin, 10.7% to chloramphenicol, 28.7% to erythromycin, and 81.% to tetracycline. Fabianova et al .…”

Comparative Analysis of Chloramphenicol-Resistant Enterococcus faecalis Isolated from Dairy Companies in Korea

“…The prevalence of chloramphenicol-resistant enterococci in dairy products has been reported in many countries, including Switzerland (45.9%), Poland (32.91%), South Africa (13%), and Turkey (10.7%) [ 9 , 15 , 18 , 36 ]. In this study, the total prevalence of chloramphenicol-resistant E. faecalis isolates (28.2%) was also shown similar to other countries, but there were significant differences in the distribution of chloramphenicol-resistant E. faecalis between the four dairy companies studied (12.9%–61.5%).…”

In vitro evaluation of the antimicrobial potential of Streptococcus uberis isolated from a local cheese from Southeastern Serbia

“…antibiotic intramammary infection therapy is initiated prior to microbiological culturing (GUTERBOCK et al, 1993;MILNER et al, 1997;WONGKATTIYA, 2008). ERBAS et al (2016) examined the susceptibility of Enterococcus spp. isolated from mastitis milk to some antibiotics, and most isolates were resistant to tetracycline.…”

“…arginine and esculine hydrolysis, the production of CO 2 from glucose, and growth in the presence of different concentrations of sodium chloride, were performed according to ISENBERG (1992). The hippurate hydrolysis test was performed according to COWAN (1993) the ability of citrate utilization was evaluated on citrate agar. the citrate agar consisted of 10 g skimmed milk powder, 2.5 g casein hydrolyzate (Torlak, Belgrade, Serbia), 5 g glucose, 18 g agar and 1000 mL distilled water.…”