黏液型铜绿假单胞菌毒力基因exoS、exoU检测及耐药性分析

Virulence Gene exoS and exoU Detection and Drug Resistance Analysis in Mucoid Pseudomonas Aeruginosa

目的分析临床分离的两种表型铜绿假单胞菌(PA)的毒力基因及其耐药性,为防止其反复感染提供治疗依据。方法收集某院2016~2018年住院患者中分离的黏液型PA 50株、非黏液型PA 50株,采用PCR法检测毒力基因exoU、exoS,KB纸片扩散法检测耐药性。结果PCR结果显示50株黏液型PA中exoS、exoU基因阳性率分别为56%(28/50)、30%(15/50),50株非黏液型PA中exoS、exoU基因阳性率分别为48%(24/50)、40%(20/50)。未检出同时携带有exoS和exoU基因的菌株;K-B纸片扩散法结果显示非黏液型PA对10种常用抗生素的耐药率高于黏液型PA,其中对氨曲南、亚胺培南、左氧氟沙星、环丙沙星的耐药率明显高于黏液型PA(P<0.05);携带exoU基因的菌株耐药率高于携带exoS基因的菌株耐药率,其中对氨曲南、亚胺培南、美罗培南、左氧氟沙星、环丙沙星的耐药率明显高于携带exoS基因的菌株(P<0.05)。结论临床分离PA中携带exoU基因的菌株比例低于携带exoS基因的菌株,但耐药率高,非黏液型PA中exoU基因阳性率比黏液型PA高,与非黏液型PA耐药率高于黏液型PA一致,黏液型PA体外药敏试验耐药率低,而临床治疗效果不佳,除生物被膜的影响外,现有的检测黏液型PA药敏方法是否能真实的放映其对抗菌药物的敏感性有待进一步研究,对PA治疗要选用敏感的抗菌药物联合治疗;选择正确的给药剂量和用药方式、充分的疗程,防止其反复感染。

OBJECTIVE To analyze the virulence genes and drug resistance of two phenotypes of pseudomonas aeruginosa(PA)isolated from clinic,and provide therapeutic basis for preventing repeated infection.METHODS Total of 50 strains of mucoid PA and 50 strains of non-mucoid PA were collected from hospitalized patients in a hospital from 2016 to 2018.The virulence genes exoU and exoS were detected by PCR,and the drug resistance was detected by KB method.RESULTS The PCR results showed that the positive rates of exoS and exoU genes in 50 mucoid PAs were 56%(28/50)and 30%(15/50),respectively.The positive rates of exoS and exoU genes in 50 nonmucoid PAs were 48%(24/50)and 40%(20/50),respectively.The strains carrying exoS and exoU genes were not detected.The results of K-B diffusion method showed that the resistance rate of non-mucoid PA to 10 commonly used antibiotics was higher than that of mucoid PA,and was significantly higher than those of mucoid PA(P<0.05)in aztreonam,imipenem,levofloxacin and ciprofloxacin.The resistance rate of strain carrying exoU gene was higher than that of strain carrying exoS gene,and was significantly higher than those carrying the exoS gene(P<0.05)in aztreonam,imipenem,meropenem,levofloxacin and ciprofloxacin.CONCLUSION The proportion of strains carrying exoU gene in clinical isolation PA is lower than that of strains carrying exoS gene,but the drug resistance rate is high.The positive rate of exoU gene in non-mucous PA is higher than that in mucous PA,and the drug resistance rate in non-mucous PA is higher than that in mucous PA.The drug resistance rate of mucous PA in vitro is low,but the clinical therapeutic effect is not good except biofilm.In addition,whether the existing methods for detecting the sensitivity of mucoid PA can truly reflect its sensitivity to antimicrobial drugs need further study.For PA treatment,sensitive antimicrobial drugs should be used in combination.The correct dosage and mode of administration should be selected,and the full course of treatment should be selected to prevent its repeated infection.