OCCURRENCE OF GENES ENCODING STAPHYLOCOCCAL ENTEROTOXINS ISOLATED FROM COW´S MILK SAMPLES

Abstract The objective of this study was to identify the occurrence of genes expressing staphylococcal enterotoxin (sea, seb, sec, and seg) and the toxin gene 1 of toxic shock syndrome (tst) in Staphylococcus aureus coming from cases of bovine mastitis in the state of Pernambuco, Brazil. We analyzed 93 isolates and we observed the presence of toxigenic gene in 20 (21.6%) samples, of which 11 (55.0%) were positive for tst gene, seven (35.0%) for the sec gene, and two (10.0%) for the seg gene. Of the 20 isolates amplified in PCR for the presence of the sec gene, seg and tst, 16 (80.0%) were positive for only one gene and four (20.0%) were positive for two genes (sec and tst). Of the 17 properties from which the samples originated, seven (41.2%) had positive samples for at least one of the genes sec, seg, and tst. This is the first record of the occurrence of the genes encoding the enterotoxin SEC and TST-1 in milk samples from cows with mastitis in the state of Pernambuco, Brazil.

摘要 本研究旨在检测巴西伯南布哥州牛乳腺炎病例分离的金黄色葡萄球菌中，葡萄球菌肠毒素（staphylococcal enterotoxin）编码基因sea、seb、sec及seg，以及毒性休克综合征毒素1基因（tst）的携带情况。本研究共分析93株分离菌株，其中20株（21.6%）携带产毒基因：11株（55.0%）tst基因呈阳性，7株（35.0%）sec基因呈阳性，2株（10.0%）seg基因呈阳性。在针对sec、seg及tst基因进行聚合酶链反应（PCR）扩增的20株分离菌株中，16株（80.0%）仅携带单一种类毒素基因，4株（20.0%）同时携带sec与tst两种毒素基因。样本来源的17个养殖场中，7个（41.2%）的样本至少携带sec、seg或tst中的一种毒素基因。本研究为巴西伯南布哥州乳腺炎患牛乳样本中编码SEC与TST-1的肠毒素基因的检出情况提供了首份记录。