禽鱼共养对淡水鲈鱼养殖环境耐药基因传播的影响及机制

Influence and mechanism of co-culture of poultry and fish on the transmission of antibiotic resistance gene in perch culture environments

摘要:

为评估单一与混合(禽鱼共养)淡水鲈鱼养殖模式中细菌耐药性及耐药基因传播特征，本研究采集2种养殖模式的沉积物、水、鱼体及鸡粪样本，分离鉴定得到243株菌，通过K-B药敏实验、PCR检测耐药基因和整合子、抗生素压力下的接合转移实验，系统比较2种模式的耐药性特征及传播机制。结果显示，禽鱼共养模式分离菌株有11种抗生素的耐药率显著高于单一养殖模式，所有样品中鸡粪便耐药情况最严重，且禽鱼共养多重耐药菌株占比更高。耐药基因检测显示，禽鱼共养模式检出17种耐药基因，单一养殖模式检出15种耐药基因，禽鱼共养模式中有11个耐药基因的检出率显著高于单一模式。整合子分析表明，禽鱼共养模式3类整合子检出率均高于单一模式，共现网络分析显示其与喹诺酮类、磺胺类耐药基因存在共现关系。接合转移实验证实，禽鱼共养模式分离株的sul1基因转移频率高于单一模式，且磺胺间甲氧嘧啶的亚抑菌浓度能提高接合转移频率。综上所述，禽鱼混合养殖模式加剧了耐药基因的富集与传播，建议加强对混合养殖模式的监管，以降低耐药性扩散风险。

Abstract:

To evaluate the bacterial antibiotic resistance and the antibiotic resistance gene transmission characteristics in the monoculture and chicken-perch co-culture models of freshwater perch, we collected the sediment, water, fish, and chicken manure samples and isolated and identified 243 strains. Through the antimicrobial susceptibility test with the K-B method, PCR detection of antibiotic resistance genes and integrons, and conjugation and transfer experiments under antibiotic pressure, we systematically compared the antibiotic resistance characteristics and antibiotic resistance gene transmission mechanisms in the two models. The results showed that the resistance rates of the isolates to 11 antibiotics in the co-culture model were significantly higher than those in the monoculture model, and the antibiotic resistance of chicken manure was the most serious among all the samples. Moreover, the proportion of multi-drug resistant strains in the co-culture model was higher. Seventeen and 11 antibiotic resistance genes were detected in the co-culture and monoculture models, respectively. The detection rates of 11 antibiotic resistance genes in the co-culture model were significantly higher than those in the monoculture model. Integron analysis indicated that the detection rates of the three types of integrons in the co-culture model were all higher than those in the monoculture model. The co-occurrence network analysis revealed a co-occurrence relationship with quinolone and sulfonamide resistance genes. The conjugation transfer experiment confirmed that the transfer frequency of sul1 of the isolates in the co-culture model was higher than that in the monoculture model, and the sub-inhibitory concentration of sulfamethazine could increase the conjugation transfer frequency. To sum up, the chicken-perch co-culture has exacerbated the enrichment and spread of antibiotic resistance genes. It is suggested that special attention should be paid to the supervision of the co-culture model to reduce the risk of antibiotic resistance spread.