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鸭源鸡杆菌的分离鉴定及耐药基因与质粒相关性分析

Isolation and identification of gallibacterium anatis and correlation analysis of drug resistance genes and plasmids

  • 摘要: 为了解我国江苏、广西、山东等地鸡、鸭、鹅等禽类鸭源鸡杆菌的耐药特点,试验采集以上地区病死禽肝脏、心脏、输卵管等组织进行鸭源鸡杆菌的分离,对分离株进行生化鉴定、16S rDNA基因的PCR鉴定与测序分析、药敏试验、耐药基因检测及18种不相容(Inc)质粒检测,并分析分离菌药敏表型与其携带耐药基因之间的相关性和分离菌携带耐药基因与Inc质粒之间的相关性。结果表明:共得到17株具有鸭源鸡杆菌特征的分离株。17株分离菌的生化鉴定结果均与鸭源鸡杆菌特征相符。17株分离菌16S rDNA基因序列与参考株的核苷酸相似性均达到97%以上,进一步确定17株分离菌均为鸭源鸡杆菌,并分别命名为2021GA01~2021GA17。17株分离菌对复方新诺明、多西环素、阿莫西林、诺氟沙星、左氧氟沙星、环丙沙星、卡那霉素的耐药率较高,分别为88%、82%、76%、76%、76%、71%和65%。在17株分离菌中,对3种及以上抗生素耐药的菌株有14株,占比为82.35%;对10种及以上抗生素耐药的菌株有7株,占比为41.18%;仅菌株2021GA10对头孢噻肟和头孢曲松钠同时耐药。在17株分离菌中,2021GA04、2021GA05、2021GA12共3株分离菌(17.65%)携带氨基糖苷类耐药基因aac(3)-Ⅱ,2021GA01、2021GA02、2021GA03等14株分离菌(82.35%)携带β-内酰胺类耐药基因TEM,2021GA01、2021GA03、2021GA04等6株分离菌(35.29%)携带β-内酰胺类耐药基因CTX-M-65,未检测出喹诺酮类耐药基因;仅2021GA09、2021GA10、2021GA11等8株分离菌携带IncFreP质粒,IncFreP质粒检出率为47.06%;其他17种质粒未检测出。17株分离菌对氨基糖苷类药物庆大霉素耐药性与其携带耐药基因aac(3)-Ⅱ情况的符合率为75%,且两者之间有显著相关性(P<0.05);虽然对氨基糖苷类药物丁胺卡那耐药性与其携带耐药基因aac(3)-Ⅱ情况的符合率为100%,但是两者之间无相关性(P>0.05);对β-内酰胺类药物美洛西林耐药性与其携带耐药基因TEM情况的符合率为50%,两者之间有显著相关性(P<0.05);对其他抗生素耐药性与其携带的耐药基因情况无相关性(P>0.05)。17株分离菌携带的耐药基因aac(3)-Ⅱ、TEM、CTX-M-65与IncFreP质粒之间均无相关性(P>0.05)。说明从多地分离出的鸭源鸡杆菌对各类抗生素表现出较强的耐药性,但IncFreP质粒与耐药基因在鸭源鸡杆菌中的传播无关。

     

    Abstract: In order to understand the drug resistance characteristics of Gallibacterium anatis from chickens, ducks, geese and other poultry in Jiangsu, Guangxi, Shandong Provinces and other places, in this experiment, the liver, heart, fallopian tube and other tissues of dead birds were collected for isolation of Gallibacterium anatis from above regions. Biochemical identification, 16S rDNA gene PCR identification and sequencing analysis, drug sensitivity test, drug resistance gene detection and 18 types of incompatible(Inc) plasmids detection were performed. The correlation between the drug-sensitive phenotypes of the isolated bacteria and its drug-resistance genes, and the correlation between the drug-resistance genes carried by the isolated bacteria and Inc plasmids were analyzed. The results showed that a total of 17 isolates with the characteristics of Gallibacterium anatis were obtained. The results of biochemical identification of the 17 isolates were consistent with the characteristics of Gallibacterium anatis. The nucleotide similarity between the 16S rDNA gene sequences of 17 isolates and the reference strains reached more than 97%,which was further confirmed that all the 17 isolates were Gallibacterium anatis,and named as 2021GA01-2021GA17,respectively. The resistance rates of 17 isolates to cotrimoxazole, doxycycline, amoxicillin, norfloxacin, levofloxacin, ciprofloxacin and kanamycin were high, which were 88%, 82%, 76%, 76%, 76%, 71% and 65%, respectively. Among the 17 isolates, 14 isolates were resistant to three or more antibiotics, accounting for 82.35%; 7 isolates were resistant to more than 10 kinds of antibiotics, accounting for 41.18%. Only isolates 2021GA10 was resistant to both cefotaxime and ceftriaxone sodium. Among the 17 isolates, a total of 3 isolates(17.65%), 2021GA04, 2021GA05, 2021GA12, carried aminoglycoside resistance gene aac(3)-Ⅱ; 14 isolates(82.35%) of 2021GA01, 2021GA02 and 2021GA03,etc., carried the β-lactam resistance gene TEM; 6 isolates(35.29%) of 2021GA01, 2021GA03 and 2021GA04, etc., carried the β-lactam resistance gene CTX-M-65. No quinolone resistance genes were detected. Only 8 isolates of 2021GA09, 2021GA10 and 2021GA11, etc., carried IncFreP plasmid, and the detection rate of IncFreP plasmid was 47.06%. The other 17 plasmids were not detected. The coincidence rate between the resistance of 17 isolates to aminoglycoside drug gentamicin and the carrying resistance gene aac(3)-Ⅱ was 75%, and there was a significant correlation between them(P<0.05). Although the drug resistance of the aminoglycoside amikacin was 100% consistent with the carrying resistance gene aac(3)-Ⅱ, there was no correlation between them(P>0.05). The coincidence rate between the resistance to β-lactam drug mezlocillin and the carrying resistance gene TEM was 50%, and there was a significant correlation between them(P<0.05). There was no correlation between the resistance to other antibiotics and the carrying resistance genes(P>0.05). There was no correlation between the carrying resistance genes aac(3)-Ⅱ, TEM, CTX-M-65 and IncFreP plasmid in 17 isolates(P>0.05). The results suggested that Gallibacterium anatis isolated from multiple locations showed strong resistance to various antibiotics, but the IncFreP plasmid was not associated with the transmission of resistance genes in Gallibacterium anatis.

     

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