Study On The Virulence-distribution And Antimicrobial Resistance In Staphylococcus Aureus Isolates From Pets In Shenyang,liaoning Province

The increasing presence of companion animals in people’s homes also increases the risk of pathogen transmission between humans and pets.Staphylococcus aureus(S.aureus)can cause animal hair folliculitis,boils,impetigo,pneumonia,endocarditis and other infectious diseases.The emergence of resistance of S.aureus to multiple antimicrobial agents,such as methicillin-resistant S.aureus(MRSA),which has caused a great public health.In this study,antibiotic resistance,virulence,spa typing and biofilm growth of S.aureus from pets in Shenyang were studied,to provide theoretical basis for the prevention and treatment of pet diseases caused by S.aureus.In this experiment,860 samples of feces,urine,tear,uterine mucus and pus were collected from 5 pet hospitals and 1 breeding base in Shenyang area.A total of 110 strains of Staphylococcus aureus were isolated,of which 16 strains were MRSA.The results of MICs showed that Staphylococcus aureus isolates from pets in Shenyang area were highly resistant to lincomycin and penicillin,with resistance rates of 95.5% and 89%.The resistance rates of cefazolin,benzoxacillin,ceftioef and cefquinoxime were5.5%,6.4%,15.5% and 12.7%.Resistance genes and virulence genes of methicillin-sensitive Staphylococcus aureus(MSSA)isolated from pets were detected by PCR,and the whole genome of MRSA was sequenced.5 resistance genes were detected,aac(6 ‘)/aph(2”)(84.2%)、nor A(90.5%)、erm C(67.4%)、tet K(69.4%)、tet M(85.3%).11 virulence genes were detected,clf A(81.8%)、clf B(75.5%)、hla(89.1%)、hlb(85.5%)、hld(87.3%)、fnb A(87.2%)、fnb B(67%)、ica A(70%)、ica C(62.7%)、ica D(72.7%)、pvl(10%).pvl genes were only present in MRSA.sea and seb gene was undetectedSpa typing of 110 strains of S.aureus showed that MSSA strains included 10 genotypes,among which t571(38.3%)and t034(34%)were the main genotypes.MRSA strains included6 types,among which t899(50%)was the main type.hld gene was undetected in t889.The biofilm formation of S.aureus isolates was determined by crystal violet staining and laser confocal microscopy.Among them,69(54.5%)of weak,8(7.3%)of strong,14(23.6%)of moderate,and 19(17.3%)of the isolates had no biofilm formation ability.The m RNA expression levels of virulence genes fnb B,clf A,fnb A and clf B of S.aureus with different resistance phenotypes were determined by q RT-PCR.The results showed that the m RNA expression level of fnb A,fnb B,clf A gene increased with the increase of antibiotic resistant species of S.aureus.There was no significant change in the 15 antibiotics resistant MSSA group.This study analyzed the resistance,virulence,spa typing and biofilm of S.aureus isolates from pets in Shenyang area,clarified the correlation between resistance and virulence of S.aureus isolates,and laid a foundation for the prevention and control of pets S.aureus infection in Shenyang area.