| Staphylococcus is the most common pyococcus, and is an important source of cross infection in hospital, it can cause serious damage of human and animal husbandry. In recent years, with the abuse of antibiotics and the wide spread of multi-resistance gene cfr from the animal origin strains, it makes that the resistance of Staphylococcus aureus has been attracted much attention. This study was carried out to investigate the epidemiological characteristics of cfr gene of Staphylococci isolated from swines and the swine workers who are in close contact with swines in Guangdong province, and the presence of clonal spread of cfr positive strains were studied, so as to provide a foundation for reasonable usage of antimicrobial agents in veterinary medicine and theoretical basis for the control of the dissemination of resistance determinants.1000 anal and nasal swab samples of the pigs and farmers were collected, 995 Gram positive strains were isolated by using mannitol salt agar. 96 cfr-positive Gram-positive bacteria were detected by PCR. The microscopy and MALDI-TOF-MS method are for the identification of 96 cfr-positive Gram-positive bacterias, 36 of them are Staphylococcus, the identified rate is 3.6%(36/995). 34 cfr-positive Staphylococcus were from pigs, and 2 were from people. The PCR method is detected by gap gene and 16 S r RNA, for identifying 36 cfr-positive Staphylococcus further. The results show 36 cfr-positive Staphylococcus are Staphylococcus sciuri(n=18),Staphylococcus saprophyticus(n=5),Staphylococcus cohnii(n=4),Staphylococcus arlettae(n=3),Staphylococcus lentus(n=1),Staphylococcus xylosus(n=1), Staphylococcus equorum(n=1),Staphylococcus aureus(n=1).The 36 cfr-positive isolated staphylococci's susceptibility of 12 antimicrobials was determined by agar dilution method. The PCR method is for detection of other resistant genes in cfr-positive Staphylococcus, for example fex A?erm A?erm B?erm C?tet M?tet A and tet B. The results show 36 strains carrying cfr gene of Staphylococcus, respectively, 23 of them were both carrying fex A, but erm A, erm B, erm C, tet M, tet A,tet B gene was not detected.Genomic DNAs of 36 cfr-positive Staphylococcus isolates were digested with Sma I and separated using PFGE for analyzing the genetic relationship. The results show that interestingly, 30 cfr-positive Staphylococcus can be succeed to type. PFGE patterns showed that 16 strains of Staphylococcus aureus were divided into 12 groups(90% similarity), which showed that most of cfr-positive Staphylococcus were non-clonal strains and showed a variety of genetic background. However, it was also found that clonal propagation strains, no difference was observed in the distribution of strain 328 and 371, 251 and 383. Strain 328 and 371 isolated from the same farm, but different sources(328, anal swab of pig; 371, nasal swab of farmer);strain 251 and 383 were isolated from different farms, 251 was the swine source Staphylococcus sciuri which came from LZ, 283 was the swine source Staphylococcus sciuri which came from BS.In summary, there are lower epidemic(3.6%) of cfr gene from Staphylococcus in Guangdong farm animal source and close contacts, cfr-positive Staphylococcus was resistant to oxacillin rate higher(63.89%) and the linezolid resistant rate is low(5.56%), multiple-resistance is serious. It showed that the cfr-positive Staphylococcus showed a variety of genetic background, but there were also clonal transmission of cfr-positive strains in the pig and worker according to the PFGE, which may threaten the health of human beings. |
PDF Full Text Request