肺炎克雷伯菌临床分离株毒力与耐药表型的关系

Relationship between virulence of clinical Klebsiella pneumoniae isolates and drug resistance phenotypes

目的 探究本地区肺炎克雷伯菌(KP)临床分离株的毒力特征及其与耐药表型的关系。方法 菌株来源于2018年8月-2020年4月四川大学华西医院收治的临床诊断为KP相关感染病例送检样本中分离出的KP菌株,根据菌株对碳青霉烯类药物的敏感性,分为碳青霉烯类耐药肺炎克雷伯菌(CRKP)组和碳青霉烯类敏感肺炎克雷伯菌(CSKP)组,两组各随机选择30株,采用基质辅助激光解吸电离质谱进行菌株鉴定,Vitek2 Compact全自动微生物系统进行药物敏感性分析,拉丝试验检测高黏表型,多重聚合酶链反应(PCR)检测毒力基因rmpA、entB、iutA、allS、aerobactin、fimH、ureA和wabG。结果 CSKP组和CRKP组对常见抗菌药物的耐药率差异均具有统计学意义(P<0.05);CSKP分离株中高黏液表型占63.30%(19/30),CRKP分离株中高黏液表型占6.70%(2/30),差异具有统计学意义(P<0.05);CSKP组的毒力基因检出率高于CRKP组(iutA除外),但rmpA、wabG、aerobactin、entB、fimH和ureA基因检出率CSKP组和CRKP组比较,无统计学差异;菌株rmpA、aerobactin、entB和allS基因携带率与常用抗菌药物的敏感性呈正相关(P<0.05),iutA基因携带率与常用抗菌药物的耐药性呈正相关(P<0.05)。结论 CSKP分离株的高黏液表型呈现率高、毒力基因检出率高。携带rmpA、aerobactin、entB和allS基因的KP分离株对常用抗菌药物的敏感性更高,携带iutA基因的KP分离株对常用抗菌药物的耐药性更高。

OBJECTIVE To explore the characteristics of virulence of clinical Klebsiella pneumoniae isolates and observe their association with drug resistance phenotypes. METHODS The K.pneumoniae strains were isolated from submitted specimens of the patients who were clinically diagnosed with K.pneumoniae-associated infection and were treated in West China Hospital of Sichuan University from Aug 2018 to Apr 2020. The strains were divided into the carbapenem-resistant K.pneumoniae(CRKP) and the carbapenem-sensitive K.pneumoniae(CSKP) group according to the susceptibility to carbapenems. 30 strains were randomly chosen from each group, the strains were identified by using matrix-assisted laser desorption ionization mass spectrometry, the drug susceptibility testing was performed by means of Vitek 2 Compact automatic microorganism system, the hyperviscosity phenotypes were detected by stringing test, and the virulence genes rmpA, entB, iutA, allS, aerobactin, fimH, ureA and wabG were detected by means of multiple polymerase chain reaction(PCR). RESULTS There were significant differences in the drug resistance rates to commonly used antibiotics between the CSKP group and the CRKP group(P<0.05). The hypermucoviscous phenotype strains accounted for 63.30%(19/30) among the isolated CSKP strains, the hypermucoviscous phenotype strains accounted for 6.70%(2/30) among the CRKP strains, and there was significant difference(P<0.05). The detection rates of virulence genes(except for iutA) of the CSKP group were higher than those of the CRKP group, while there were no significant differences in the detection rates of rmpA, wabG, aerobactin, entB, fimH and ureA genes between the CSKP group and the CRKP group. The carrying rates of rmpA, aerobactin, entB and allS genes of the strains were positively correlated with the susceptibility to the commonly used antibiotics(P<0.05),and the carrying rate of iutA gene was positively correlated with the drug resistance to the commonly used antibiotics(P<0.05). CONCLUSION The hypermucoviscous phenotype CSKP strains show high isolation rate, and the detection rates of virulence genes are high. The isolated K.pneumoniae strains that carry with rmpA, aerobactin, entB and allS genes are more susceptible to the commonly used antibiotics, and the isolated K.pneumoniae strains that carry with iutA gene are more resistant to the commonly used antibiotics.