Occurrence of virulent multidrug-resistant Enterococcus faecalis and Enterococcus faecium in the pigs, farmers and farm environments in Malaysia

PeerJ

Chun Wie Chong¹  Cindy Shuan Ju Teh²  Peck Toung Ooi³  Shiang Chiet Tan⁴  Kwai Lin Thong⁴ 

[1] Department of Life Sciences, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia;Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia;Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia,Selangor Darul Ehsan, Malaysia;Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia;

关键词: Enterococcus faecium;    Enterococcus faecalis;    MDR;    Farmers;    Virulence genes;    Pigs;   

DOI  :  10.7717/peerj.5353

来源: DOAJ

【 摘 要 】

Background Enterococcus faecalis and Enterococcus faecium are ubiquitous opportunistic pathogens found in the guts of humans and farmed animals. This study aimed to determine the occurrence, antimicrobial resistance, virulence, biofilm-forming ability and genotypes of E. faecalis and E. faecium from swine farms. Correlations between the genotypes, virulotypes, antibiotic resistance, and the environmental factors such as locality of farms and farm hygiene practice were explored. Methods E. faecalis and E. faecium strains were isolated from the oral, rectal and fecal samples of 140 pigs; nasal, urine and fecal samples of 34 farmers working in the farms and 42 environmental samples collected from seven swine farms located in Peninsular Malaysia. Antibiotic susceptibility test was performed using the disk diffusion method, and the antibiotic resistance and virulence genes were detected by Polymerase Chain Reaction. Repetitive Extragenic Palindromic-Polymerase Chain Reaction and Pulsed-Field Gel Electrophoresis were performed to determine the clonality of the strains. Crosstab/Chi-square test and DistLM statistical analyses methods were used to determine the correlations between the genotypes, virulence factors, antibiotic resistance, and the environmental factors. Results A total of 211 E. faecalis and 42 E. faecium were recovered from 140 pigs, 34 farmers and 42 environmental samples collected from seven swine farms in Peninsular Malaysia. Ninety-eight percent of the strains were multidrug-resistant (resistant to chloramphenicol, tetracycline, ciprofloxacin and erythromycin). Fifty-two percent of the strains formed biofilms. Virulence genes efa, asaI, gelE, esp, cyl and ace genes were detected. Virulence genes efa and asaI were most prevalent in E. faecalis (90%) and E. faecium (43%), respectively. Cluster analyses based on REP-PCR and PFGE showed the strains were genetically diverse. Overall, the strains isolated from pigs and farmers were distinct, except for three highly similar strains found in pigs and farmers. The strains were regional- and host-specific. Discussion This study revealed alarming high frequencies of multidrug-resistant enterococci in pigs and swine farmers. The presence of resistance and virulence genes and the ability to form biofilm further enhance the persistence and pathogenicity of the strains. Although the overall clonality of the strains were regionals and host-specific, strains with high similarity were found in different hosts. This study reiterates a need of a more stringent regulation to ensure the proper use of antibiotics in swine husbandry to reduce the wide spread of multidrug-resistant strains.

【 授权许可】

Unknown