Isolation, Identification And Drug Resistance Of Methicillin - Resistant Golden Grapevine In Pig Herds In

As the large scale of the present pig industry and the wide range of related usa ge of animal products and food groups, the discovery of Methicillin-Resistantst Stap hylococcus aureus, MRSA, sparked widespread concern to the swine industry a-nd i ts products over all circles. So far, the proportion of human and animal infections caused by MRSA shows an increasing trend, and MRSA often causes outbreaks an-d prevalence of infections,which of great influence. mecA gene is MRSA’s specifi-c resistance gene, and femA functional gene is cofactor to MRSA’s drug resistanc e, both of which play very important role in the drug resistance. Therefore, this tes-t uses mecA and femA gene for dictation, and the positive result was diagnosed a-s MRSA. In this. paper, the Staphyloco-ccus aureus isolated from pigs collected fro m 120 samples from farms of Sichuan was amplified by PCR. Carrying drug resist ance testing and SCCmec typing to iden-tified pig origin MRSA.The main results of this test are as follows:1.The separation and purification of Staphylococcus aureus:collected 120 porti-on of nasal swabs, stool samples from 12 large-scale pig farms in the Sichuan reg-ion, from March 2013 to December 2013.Inoculation to serum agar, cultured in 37 ℃ for 18h.Picked up golden、tartrazine or grain, regular edge and the surface smoo-th round colonies. After gram stain and microscopic examination, inoculation to yo-lk mannitol high salt agar medium. After cultured at 35℃ for 24 to 48h, identifie-d the golden yellow single colony circled with yellow "fried egg" shaped halo on t-he yolk mannitol high salt agar medium, and inoculated to 3ml M-H broth with N-aCl of 2%-4%, on a rotary shaker for purified culture at 35℃ for 6-8h. A total 6 0 strains of Staphylococcus aureus were isolated.2.Drug sensitivity test of the 22 stains of MRSA:Using the K-B disc diffuse-on recommended by Clinical and Laboratory Standards Institute (CLSI) to do drug sensitivity test of MRSA. Using Staphylococcus aureu ATCC25923 as qualitycont-rol strains to test the drug resistance of 22 strains of isolated MRSA to four kin-ds of β-lactam drug and seven kinds of non-β-lactam drug. Drug sensitivity test r-esults showed that the separation of the MRSA strains also had different resistance among β-lactam drugs and non-β-lactam drugs, mainly was 4,5,6-resistant.The resis -tance rate of the 22 stains of MRSA to penicillin, cephalexin, cefoxitin, cefoperazo-ne were 100%;and they were sensitive to vancomycin and tetracycline;the resistanc-e rates against ciprofloxacin, erythromycin, trimethoprim-sulfamethoxazole, and sulfas-exazole were respectively 4.5%,4.5%,22.7% and 18.2%.SCCmec genotyping result-s said, SCCmec Ⅳ a type of resistance rates about non-β-lactams were 0%, while the five SCCmec I type strains of non-β-lactam drug resistance was relatively hig-h.The results of the sensitivity test showed that the 22 strains of MRSA isolated i-n the test was obviously of multi-drug resistance.3.The PCR identification and SCCmec typing of MRSA:Apply PCR identific-ation to mecA and femA gene for further verification to Staphylococcus aureus, th-e gene test positive were judged MRSA.PCR for the SCCmec genotyping to isolat-ed MRSA. The result shows the detection of 22 strains of MRSA and the detectio n-n rate 18.3%(22/120).The result showed that the predominant type of swine MRS A is SCCmecIVa, in which 17 strains of SCCmecⅣa、5 strains of SCCmec I. In t-he 22 strains of MRSA,5 strains of the 5 and 6-resistant antibiogram type belonge d to the type of SCCmec I,and the 4-resistant antibiogram type belonged to the typ e of SCCmecIVa.