Isolation, identification and antibiotic resistance test of Enterococcus spp. on shell surface of fresh egg

  Objective  To detect the presence and drug resistance of Enterococcus spp. on fresh egg surface.

  Methods  Fresh eggs were sampled from a hennery in Handan city. Bacteria specimens were collected by wiping egg surfaces around with sterile saline cotton swabs. Bile esculin azide agar (BEAA) was used in bacterial isolation and cultivation of Enterococcus spp. PCR amplification was conducted with universal primers 16S rDNA and amplification products were sequenced for the identification of Enterococcus spp.. Drug resistance of the isolated Enterococcus spp. strains was determined with paper disk method.

  Results  A total of 124 strains of 5 kinds of Enterococcus spp. were isolated from 160 specimens, with an isolation rate of 77.5%. The two main kinds of isolated strains were Enterococcus spp. E. faecalis (58.1% of all isolated strains) and E. faecium (13.1%) , followed by E.avium (5.0%), E. gallinarum (1.9%), and E. casseliflavus (1.2%). Various resistances to 14 antibiotics were observed for the isolated Enterococcus spp. strains and all the 124 isolated strains were multidrug resistant, with the resistance at least to 3 antibiotics and as many as to 9 antibiotics.

  Conclusion  The detection rate of Enterococcus spp. on fresh egg surface is high and antibiotic resistance is prevalent for the isolated Enterococcus spp. strains. The study results needs to be concerned.