规模化猪场仔猪断奶腹泻大肠杆菌耐药性监测

采用WHO推荐的Kirby-Bauer法,以分离自浙江省10个规模化猪场的60株病原性大肠杆菌为材料,开展了对兽医临床上常用的21种抗菌药物的耐药性监测.结果表明,60株病原性大肠杆菌对抗菌药物已发生普遍的耐药性,其中对复方新诺明(88.3%)、氯霉素(81.0%)、链霉素(78.3%)、痢菌净(77.3%)、痢特灵(75.0%)、喹乙醇(75.0%)等的耐药性最强.对单诺沙星、环丙沙星及诺氟沙星的耐药率也很高,其耐药率分别高达78.8%、59.3%和56.7%.60株大肠杆菌共有57种耐药谱型,绝大多数为多重耐药,其中有4株可同时耐受14种抗菌药物.受检菌株中除1株外,59株均对2种或多种抗菌药物耐药:对1～3种,4～6种,7～9种,10～12种及13～15种抗菌药物耐药的分别有6株(10.0%)、11株(18.3%)、17株(28.3%)、17株(28.3%)和9株(15.0%);对8种抗菌药物耐药的菌株占比例最大(16.7%),其次是对10种抗菌药物耐药(15.0%)和对6种抗菌药物耐药(11.7%)的菌株;不同地区、不同规模化猪场的大肠杆菌菌株的耐药性存在一定差异.临床上应用时间不长的氟苯尼考耐药率已达60.9%,值得关注.

Surveillance of resistant pathogenic E.coli from post-weaning diarrhea on intensive pig farms in Zhejiang province

Antimicrobial susceptibility testing was performed on 60 clinical Escherichia coli isolates from pigs with post-weaning diarrhea in 10 intensive pig farms in Zhejiang province. The results showed that all the 60 pathogenic E.coli isolates have developed various degrees of resistances to 21 commonly used antimicrobials. 59 out of the 60 isolates exhibited resistances to 2 or more antimicrobials: 6 (10%), 11(18.3%), 17(28.3%), 17(28.3%), and 9(15.0%) of the 60 isolates were resistant to 1-3, 4-6, 7-9, 10-12 and 13-15 antimicrobial agents, respectively. Resistance percentage to 8 antimicrobial agents accounted for the highest (16.7%), followed by resistance percentage to 10 or 6 antimicrobials (15.0% and 11.7% respectively). Among the 60 isolates, there were 57 different resistant patterns; most of the isolates showed multiresistance and 4 of them were able to tolerate even 14 antimicrobials. Among the 21 commonly used antimicrobial agents, resistance occurred most frequently to SXT (sulfarmethoxazole/Trimethoprim) (88.3%), CM(Chloramphonicol)(81.0%), SM (Streptomycin)(78.3%), Ma(Maquindox)(77.3%), FD(Furazolidon)(75.0%), and HMQ (Olaquindox) (75.0%). Level of resistance to DAN (Danofloxacin ),ClP (Ciprofloxacin ) and NOR (Norfloxacin) was also high, the corresponding resistance frequency reached as high as 78.8%,59.3% and 56.7%, respectively. The resistance frequency varies with districts and pig farms. It is noteworthy that the relatively new antibiotic FLO (Florfenicol ) was 60.9% resistant in the study. It is therefore in urgent need to establish an effective surveillance system and to further study on antimicrobial resistance especially multiresistance of Escherichia coli.