高效液相色谱快速检测牛奶中青霉素中间体 以及2种青霉素类药物

采用高效液相色谱法建立了同时检测牛奶中青霉素类抗生素中间体6-氨基青霉烷酸(6-APA)及2种青霉素类药物氨苄青霉素(AMP)、阿莫西林(AMO)的方法。检测条件如下:色谱柱为Xterra?MS C18柱;流动相为乙腈:0.1%氨水=5:95(V/V)等度洗脱;柱温35℃;流速1.0 mL·min-1;进样量10μL;紫外检测波长200 nm。结果表明,6 min内可实现3种青霉素类抗生素(PENs)的快速分离检测。方法在0.125~10.00 mg·L-1范围内有良好的线性,相关系数(r2)0.9972~0.9991,加标回收率为89.09%~99.64%,相对标准偏差为1.21%~7.35%。该方法简便、快速,可应用于市售牛奶中PENs的快速检测。     

放射免疫法快速检测鸡肉中青霉素类药物残留

主要探讨应用Charm Ⅱ放射免疫分析方法检测鸡肉中青霉素类药物残留。确定制样和控制点设定的方法,评价了免疫反应体系的灵敏度和特异性,验证了青霉素类药物最大残留限量的检测稳定性。90min可出检测结果。     

Enhanced killing of penicillin-treated S. aureus by host defences: Effects of amoxycillin, cloxacillin and nafcillin in vitro and in experimental mastitis

The effects of pretreatment of Staphylococcus aureus with subMIC or 10 × MIC amoxycillin, cloxacillin and nafcillin on subsequent killing by bovine neutrophils or sensitivity to lysostaphin were examined in vitro, using penicillinase positive and negative strains. All penicillins increased the susceptibility of S. aureus to bovine neutrophils; with amoxycillin this was most marked with the penicillinase negative strain. Cloxacillin pretreatment was significantly more effective than nafcillin or amoxycillin in some tests and equally effective in others. The sensitivity of S. aureus to lysostaphin was increased following cloxacillin or nafcillin exposure. In a mouse model of mastitis, more cloxacillin and nafcillin-treated S. aureus (at 1/4 MIC) were killed than untreated bacteria 1 hr after infection but by 4 hr no differences were found. No differences were seen after intramammary infection with 10 × MIC penicillin-treated S. aureus. In glands with established chronic mastitis both cloxacillin and nafcillin at high doses failed to kill staphylococci. These findings indicate that prior exposure to penicillins increases staphylococcal susceptibility to killing by neutrophils but following phagocytosis, intracellular bacteria are protected from the lethal action of penicillins.