肉鸡养殖场环境水体中沙门菌的耐药性与噬菌体的抑菌作用

Antibiotic Resistance and Bacteriophage Treatment of Salmonella Isolated from Water Around Chicken Farm

为了调查肉鸡养殖场周围水体存在的沙门菌,分析其耐药情况,并探讨噬菌体对耐药菌株的抑制效果,本试验选择肉鸡场附近水体,采取表层水样5份,使用选择培养基进行沙门菌分离纯化,通过药敏试验评估所分离沙门菌的耐药性;此外,从同一水样中分离噬菌体,选取不同感染复数(MOI)的噬菌体单独应用,以及与不同抗生素联合应用,检测噬菌体及其与抗生素联合应用对耐药沙门菌的抑制作用。结果显示:自5份水样中分离并鉴定出11株沙门菌,均对常用抗生素存在耐药现象,且多重耐药率高达63.64%(7/11),单株细菌多重耐药最多对6种抗生素耐药;通过对比不同试验条件,当MOI为1∶10时,噬菌体对沙门菌的抑制效果最好;耐药沙门菌在噬菌体作用下,对抗生素的敏感性增加,表现为抗生素抑菌环直径增大;噬菌体与氨苄青霉素(AMP)联合应用时,可极显著降低沙门菌对试验小鼠的致死率(P<0.01)。结果表明,环境水体中存在的沙门菌具有广泛的抗生素耐药性,而同水源噬菌体则对沙门菌具有显著的抑菌效果,并可以增强耐药菌对抗生素的敏感性。

This study investigated the distribution of antibiotic resistant Salmonella in the water around poultry farm and their treatment by bacteriophages.5 samples of surface water around poultry farm were selected for isolation and purification of Salmonella using selective medium,and drug resistance of the isolated Salmonella was evaluated by drug sensitivity test.In addition,bacteriophages in the same water sample were isolated and propagated alone or in combination with different antibiotics at different MOI to detect the inhibition effects against drug-resistant Salmonella.The results showed that 11 Salmonella isolates were identified from 5 water samples,all of which were resistant to commonly used antibiotics,and 63.64%(7/11)were multi-antibiotic resistant,multiple resistance of a single strain could up to 6 antibiotics;after comparing different experimental conditions,when MOI was 1∶10,bacteriophage had the best inhibitory effect on Salmonella;the susceptibility of drug-resistant Salmonella to antibiotics was increased by bacteriophage,which showed with the increasing diameter of antibacterial ring;bacteriophage combined with ampicillin(AMP)significantly reduced the mortality of Salmonella in mice(P<0.01).Thus,Salmonella from environmental water appears to resist a broad range of antibiotics,homologous phage has a significant antibacterial effect on Salmonella,and can enhance the sensitivity of drug-resistant Salmonella to antibiotics.