| Enterococcus faecalis was known as symbiotic bacteria, but recently, there are increasing cases about Symbiotic bacteria infection on humans and animals. The possible reason for the infections was drug resistance and virulence increasing. To uncover and evaluate the potential threat to public health and swine industury, this study isolated and identified the porcine Enterococcus faecalis, and then drug resistence and polymerase chain reaction were carried out to characterize the drug resistence and virulence associated genes.349 fresh pig fecal samples were collected from seven different regions in Jiangxi province from 2014 to 2015, including 197 diarrheal feces and 152 normal fecal samples.By using the double selective culture screening and PCR amplification methods, 226 strains of Enterococcus faecalis were isolated and identified. Isolation rate of Enterococcus faecalis from all the samples was 64.8%, of which, isolation rate of enterococcus faecalis(72.6%) is higher than other samples(54.6%). The isolation rate from Jiujiang area was the highest(82.2%), the second(80.4%) in Yichun area, and the lowest(35.9%) in Fuzhou area, and the regional separation rate was significantly different.Drug resistence assay was conducted on 226 Enterococcus faecalis isolates with seven drugs. Results indicated that multiple drug resistence phenomenon was very common on Jiangxi Enterococcus faecalis isolates, 117(78.32%) porcine Enterococcus faecalis isolates were resistant to multiple drugs.The erythromycin and doxycycline resistance rates were 97.35% and 92.48%, respectively, while the ciprofloxacin and florfenicol resistance rate(65.04% and 61.95%) were relative low, respectively.Only 3 strains resistant to ampicillin were discovered in Ganzhou. There were 14 resistance phenotype among the 226 Enterococcus faecalis strains, of which 3rd and 4th resistance phenotype and the ERY+CIP+DOX+FFC resistance phenotype were more popular.The doxycycline resistant rate was significant difference.To detect the florfenicol resistance gene of the 226 Enterococcus faecalis strains by using PCR method and sequence blast, it suggested that there are 158 strains containing the fex A gene(69.91%),13 strains containing the cfr gene(5.75%) and 10 strains containing fex B gene, all of which were resistant to the florfenicol. The phenotype in this experiment to florfenicol resistant strains were detected in the resistant gene, and 22 strains carrying resistance genes of the isolates showed no resistance to florfenicol. The strains possessing fluorobenzene fex A gene distributed widely. The positive detection rate could reach up to 98.57%, indicating that the main mechanism of Jiangxi area test resistance to florfenicol is specific fex A gene mediated efflux.According to the results of six kinds of virulence gene detection of 226 strains by PCRmethod, it revealed that 98.23% of Enterococcus faecalis carried at least a virulence gene and the gene detection rates from high to low were efa A, ace, gel E, agg, esp and cly A.There were 170 strains(75.22%) carrying 3~5 virulence genes which were detected; 25 different virulence genotypes carrying gel E+ace+efa A genotype isolates in Jiangxi province is very popular. Using beta hemolysis and gelatin lysis phenotype detection method to detect the 226 strains found that the corresponding genotype and phenotype are not exactly same. No significant difference were observed between porcine Enterococcus faecalis isolates in the drug resistence number and rate, indicating no relatioship between drug resistence number and rate. |
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