大熊猫源肺炎克雷伯菌耐药性和分子分型研究

Drug resistance and molecular typing of Klebsiella pneumoniae isolated from giant panda

【目的】对大熊猫源肺炎克雷伯菌进行耐药性及分子分型分析,掌握肺炎克雷伯菌在大熊猫圈养种群中的耐药和流行情况,指导临床用药。【方法】对2018–2019年收集到的178株大熊猫源肺炎克雷伯菌使用纸片扩散法(K-B法)分析耐药表型,使用Wafergen Smartchip超高通量荧光定量PCR法分析其耐药基因和可移动遗传元件,使用多位点序列分型(MLST)法分析其序列类型(ST)。【结果】178株大熊猫源肺炎克雷伯菌对多西环素耐药率最高(15.2%),而且2019年分离到的肺炎克雷伯菌对头孢噻肟、亚胺培南和阿奇霉素的耐药性显著高于2018年(P<0.05);检出耐药基因106种(106/227),可移动遗传元件11种(11/19),涉及的耐药机制主要为外排泵(42.0%)、抗生素失活(41.8%)和改变作用靶位(16.2%);MLST分型显示大熊猫源肺炎克雷伯菌主要分为42个不同的ST型,且ST型与耐药性具有一定的相关性。【结论】从2018年到2019年大熊猫源肺炎克雷伯菌对β-内酰胺类和大环内酯类抗生素耐药率有所增加,耐药机制以外排泵和抗生素失活为主。ST17、ST23和ST4007可能是大熊猫源肺炎克雷伯菌的优势型。在大熊猫临床诊疗中,应注意抗生素的合理规范使用,以防耐药性进一步增加。

[Objective] This study aims to analyze the drug resistance and molecular types of Klebsiella pneumoniae isolated from giant panda(Ailuropoda melanoleuca), which is expected to clarify the drug resistance and prevalence of K. pneumoniae in the captive population of giant panda and to guide clinical drug use. [Methods] For the 178 K. pneumoniae strains of giant panda collected from 2018 to 2019, the drug resistance phenotypes were analyzed with the Kirby-Bauer(K-B) disk diffusion method, drug resistance genes and mobile genetic elements by Wafergen Smartchip high-throughput fluorescent quantitative PCR, and sequence types(STs) by multi-locus sequence typing(MLST). [Results] The 178 strains had the highest resistance rate to doxycycline(15.2%) and the resistance to cefotaxime, imipenem, and azithromycin was significantly higher in strains isolated in 2019 than in 2018(P<0.05). A total of 106 drug resistance genes(106/227) and 11 mobile genetic elements(11/19) were detected. The resistance mechanisms were mainly efflux pumps(42.0%),antibiotic inactivation(41.8%), and altered target sites of action(16.2%). MLST classified the strains into 42 STs, and ST was correlated with drug resistance. [Conclusion] The resistance rate of K. pneumoniae strains from giant panda to β-lactam and macrolide antibiotics increased from 2018 to 2019. The drug resistance mechanisms of the strains were mainly efflux pumps and antibiotic inactivation. ST17, ST23 and ST4007 may be the dominant types. In the clinical treatment of giant pandas, antibiotics should be rationally used to prevent further enhancement of drug resistance.