渭河杨凌段水系中头孢曲松耐药菌和耐药基因

调研了杨凌抗生素使用和过期抗生素处理情况，研究了渭河杨凌段及其在杨凌境内主要支流中耐药菌（主要为耐头孢曲松细菌）及常见耐药基因的分布特征.杨凌区β-内酰胺类药物占抗生素总用量的55.0%，64.0%的过期抗生素被合理处理；水样中耐头孢曲松细菌平均浓度均大于500CFU/mL，分离到5种气单胞菌（n=44）和1株大肠杆菌；45株（100.0%）菌全部耐受氨苄西林，阿莫西林/克拉维酸和头孢曲松，多重耐药率为95.6%；水样总DNA中ampC，sul1，sul2，sul3，tetB，tetC，tetM，aadA，cmlA，catA，bla_TEM，bla_NDM，aph（2’）-Id和aac（6’）-Ib检出率均为100.0%，15株耐头孢曲松代表菌中ampC与bla_TEM检出率均为100.0%.渭河杨凌段及其主要支流中多重耐药细菌检出率较高，耐药基因多样化.研究可为杨凌区水体中耐药菌污染治理提供参考.

Prevalence of ceftriaxone-resistant bacteria and drug-resistance encoding genes in Weihe River and its tributaries in Yangling Section

In this study, the situation of antibiotic usage and disposal of expired antibiotic in Yangling city, and the distribution of antibiotic-resistant bacteria (mainly ceftriaxone resistant bacteria) and antibiotic resistance genes in Weihe River and its main tributaries in Yangling city were studied. The results indicate that β-lactam accounted for 55.0% of total antibiotics usage in Yangling, and 64.0% of the expired antibiotics were properly disposed. The numbers of ceftriaxone-resistant bacteria in all water samples were higher than 500CFU/mL. Five Aeromonas species (44isolates) and one Escherichia coli isolate were recovered. All (100.0%) isolates were resistant to ampicillin, amoxicillin/clavulanate and ceftriaxone, and the rate of multidrug resistant isolates was 95.6%. The detection rates of ampC, sul1, sul2, sul3, tetB, tetC, tetM, aadA, cmlA, catA, bla_TEM, bla_NDM, aph(2')-Id and aac(6')-Ib in 15water samples were 100.0%, and ampC and bla_TEM were detected in all 15ceftriaxone resistant isolates. Frequent occurrence of multidrug resistant bacteria and drug resistance genes were demonstrated in Weihe River and its tributaries in Yangling Section. This study can provide useful data for reduction of drug resistant bacteria and gene in the water in Yangling, Shaanxi.