| Summary: | 碩士 === 弘光科技大學 === 食品暨應用生物科技所 === 99 === Staphylococcus spp. Willacy exists on the skin of human and warm-blood animals, and also is the pathogen of food poisoning and mastitis. Production enterotoxins of Staphylococcus spp. is the major cause of food poisoning. Since antimicrobial agents were wildly used for many year, Staphylococcus spp. showed highly multiple drug resistant recently and became a issue of public health. In this study, Staphylococcus spp. were isolated from goat and determinate by PCR. Results showed that a total of 515 isolates were obtained, including 168 S. xylosus , 153 S. aureus, 133 S. intermedius ,61 S. epidermidis , 4 S. carnosus , and 2 S saprophyticus. Also enterotoxins weter analyzed using PCR, 42 isolates in 515 Staphylococcus spp. Were demonstrated containing enterotxins, which encompassed 21 enterotoxin C (50%), Benterotoxin D (30.95% ), and enterotoxin E (2.38%), respectively. For antimicrobial drug Susceptibility test, in this study ,97 strains of S. xylosus and S. aureus were analyzed for their antimicrobial resistance to 20 forbidden-used drugs in Taiwan. Results showed that. These strains were highly resistant to penicillin G, tetracyline, and streptomycin ,which were 72.16% , 70.10%, and 28.87%, respectively, All of these strains were susceptible to rifamin, neomycin, cefepime, bactracin , ofloxacin,and methicillin. In addition, mecA gene were also confirmed by PCR, none of MRSA (methicillin-resistant Staphylococcus aureus) was found. Furthermore, pulsed-field gel electrophoresis (PFGE) was used for molecular typing in this study SmaI is regarded as the gold standard resistriction enzyme for typing S. aureus. However, genomic DNAs of some S. aureus. strains was resistant to SmaI, but could be digested with Cfr9I. Previous study suggested that. The reason for strains are nontypeable by SmaI-PFGE is because of the action of an indirectly revealed because of the action of an indirectly revealed DNA methltransferase which modifies the consensus sequence CmCNGG at the second cytosine. Cfr9I is a neoschizomer of SmaI that cut within the same recognition sequence but at different position. Thus Cfr9I was used for molecular typing in this study. Results showed the strains could be grouped into 63 subtypes and the discriminatory index was raised to 0.347,In addition. PFGE patterns could be divided into to 3group,i.e., A, B.and C. Strains in group A were goat S. aureus isolates collected in 2010,and genomic DNAs of these strains were methylated. In contrast, strains in group B were goat S. aureus isolates collected in 2010, genomic DNAs of these strains were not methylated. For 36 goat S. xylosus isolates collected in 2010 and 1994, the genomic DNAs of these isolates could be digested with SmaI and 33 PFGE patterns were obtained. The similarities of these isolates were higher than 37%.
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