猪鸡致病菌β-内酰胺酶、超广谱β-内酰胺酶检测与药敏试验

Detection of Beta-lactamase and Extended-spectrum Beta-lactamase and Antibiotic Susceptibility Test Analysis of Pathogens Isolated from Pig and Chicken

对分离的猪鸡致病菌,分别进行了?-内酰胺酶、超广谱β-内酰胺酶(ESBLs)检测,并用试管二倍稀释法测定了β-内酰胺环类抗生素或β-内酰胺环类抗生素与抑制剂舒巴坦联用对非产酶菌、产?-内酰胺酶菌、产ESBLs菌的抗菌活性.结果表明,43株分离菌的大多数可产生?-内酰胺酶,3株鸡志贺氏菌为ESBLs阳性菌株.30株分离产酶菌均对阿莫西林、氨苄西林耐药(MIC≥32 μg/ml),16株非产酶菌(标准菌株及分离株)中的15株对阿莫西林、氨苄西林敏感,只有一株非产酶分离菌耐药.氨苄西林与舒巴坦以2∶1、4∶1配比联用时,其对分离产酶菌的MIC值分别降低10~40倍、10~20倍.临床致病菌对三代头孢均敏感,与舒巴坦以2∶1、4∶1配比联用时,三代头孢的MIC值不变.当头孢噻呋、头孢曲松与舒巴坦以2∶1配比联用时,其对产ESBLs菌的MIC值降低2～4倍.

The antibacterial activity of beta-lactam antibiotics or their combinations with inhibitor sulbactum against non-lactamase-producing strains, lactamase-producing and ESBLs-producing isolates was evaluated with two-fold dilution method after pathogens isolated from pigs and chickens were detected, respectively, for beta-lactamase and extended-spectrum beta-lactamases(ESBLs).The results revealed that most of the 43 clinically isolated strains could produce beta-lactamase and 3 strains of Shigella isolated from chicken samples produced ESBLs. All of the 30 lactamase-producing strains isolated and only one of the 16 non-lactamase-producing strains were resistant to amoxicillin and ampicillin. MICs of ampicillin against lactamase-producing isolates decreased by 10-40 and 10-20 times, respectively, when it was conbined with sulbactam at ratio of 1 2 and 1 4. All clinical isolates were susceptible to third-generation cephalosporins.The MICs of third-generation cephalosporins against lactamase-producing isolates did not change when they were conbined with sulbactam. MICs of ceftiofur and ceftriaxone against ESBLs-producing isolates decreased by 2-4 times when they were conbined with sulbactam.