Antimicrobial Resistance Genes Associated with Enterococci from Poultry in Egypt, First Reporting of mecA in Enterococcus from Poultry Source

Little information available for the Egyptian setting. 117 cloacal swabs were collected from diseased poultry located in 6 districts in Egypt. Isolates were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The antibiotic susceptibility testing of Enterococcus faecium and Enterococcus gallinarum isolates against 22 antibiotics was performed with the MICRONAUT system for Gram-positive bacteria. The presence of 12 resistance-associated genes (tetK, tetL, tetM, tetS, tetO, erm(B), msrC, aac6-aph2, vanA, vanB, vanC1 and mecA) was investigated by PCR. Thirty one Enterococcus isolates have been detected, Enterococcus faecium (n=22) and Enterococcus gallinarum (n=9) strains were isolated. All Enterococcus faecium and Enterococcus gallinarum isolates were multidrug-resistant. More than 15% of Enterococcus faecium isolates were resistant to vancomycin. Resistance rates to other antibiotics ranged between 31.8% for teicoplanin to 86.4% for penicillin G, respectively. Enterococcus gallinarum isolates showed a resistance rate of 100% to cefoxitin, ceftaroline, clindamycin, daptomycin, erythromycin, gentamicin and oxacillin. The resistance genes most often found were msrC, erm(B), aac6-aph2 and mecA. The vanB gene was identified in two Enterococcus faecium isolates from which one was resistant to vancomycin whereas vanC1 was detected in 6 Enterococcus faecium and Enterococcus gallinarum isolates. Tetracycline resistance-associated genes (tetK, tetL, tetM, tetO and tetS) were found in 25 isolates whereas mecA was detected in nine isolates. The study is the first report for mecA gene in Enterococcus. The development of resistance to antibiotics in poultry production needs special attention and investigation. The usage of antimicrobials in Egypt should follow WHO and OIE recommendations.