铜绿假单胞菌的耐药性及毒力基因研究

Study on drug resistance and virulence genes of Pseudomonas aeruginosa

目的 探讨铜绿假单胞菌(Pseudomonas aeruginosa,PA)的耐药性及其毒力基因的分布特征,为临床合理使用抗生素和开发新型抗菌药物提供理论依据。方法 选取新乡医学院第三附属医院临床送检的316株PA菌株,纸片扩散法(Kirby-Bauer method)进行抗生素敏感性测试。利用PCR技术检测毒力基因exoS、exoU的携带情况。结果 316株PA菌株中,95株为黏液型(30.06%),221株为非黏液型(69.94%)。黏液型PA中,67株来自痰液(70.53%),14株来自创面分泌物(14.74%),9株来自中段尿(9.47%),5株来自血液(5.26%)。非黏液型PA中,170株来自痰液(76.92%),22株来自创面分泌物(9.95%),13株来自中段尿(5.88%),16株来自血液(7.24%)。黏液型PA中,34株来自呼吸科(35.79%),12株来自烧伤科(12.63%),20株来自ICU(21.05%),4株来源于神经内科(4.21%),4株来源于肿瘤科(4.21%),3株来源于血液科(3.16%),其他科室18株(18.95%)。非黏液型PA中,110株来自呼吸科(49.77%),33株来自烧伤科(14.93%),22株来自ICU(9.95%),21株来源于神经内科(9.50%),13株来源于肿瘤科(5.88%),11株来源于血液科(4.98%)其他科室11株(4.98%)。呼吸科、ICU、其他科室构成比差异有统计学意义(P<0.05)。黏液型PA对美罗培南、亚胺培南、阿米卡星的耐药性低于10%,而对头孢他啶的耐药性超过30%。此外,尚未发现对多粘菌素B产生耐药性的菌株。对于非黏液型PA,其对美罗培南、亚胺培南的耐药性同样低于10%,但对头孢他啶、左氧氟沙星、环丙沙星、庆大霉素的耐药性超过30%,同样未出现对多粘菌素B耐药的菌株。在不同分型的铜绿假单胞菌菌株中,对美罗培南、亚胺培南、庆大霉素、阿米卡星的耐药性差异有统计学意义(P<0.05),而对哌拉西林/他唑巴坦、头孢他啶、头孢吡肟、左氧氟沙星、环丙沙星的耐药性差异无统计学意义(P>0.05)。在黏液型PA中,75株携带毒力基因,占比达到78.95%。29株菌体携带(exoU+/exoS-)基因型,占30.53%,而46株菌体携带(exoU-/exoS+)基因型,占48.42%。另外,有20株菌体未检出毒力基因,占21.05%。在非黏液型PA中,213株携带毒力基因,占比高达96.38%。其中,88株菌体携带(exoU+/exoS-)基因型,占39.82%,125株菌体携带(exoU-/exoS+)基因型,占56.56%。未检出毒力基因的菌体有8株,占3.62%。对比不同分型的铜绿假单胞菌菌株,毒力基因携带率差异有统计学意义(P<0.05)。(exoU+/exoS-)基因型与(exoU-/exoS+)基因型之间的携带率差异无统计学意义(P>0.05)。exoU+组(n=117)与exoU-组(n=199)菌株在对哌拉西林/他唑巴坦、美罗培南、亚胺培南、左氧氟沙星、环丙沙星、阿米卡星的耐药率差异有统计学意义(P<0.05),而在对头孢他啶、头孢吡肟、庆大霉素的耐药率差异无统计学意义(P>0.05)。结论 PA菌株以非黏液型为主,主要分离自呼吸科,不同分型PA菌株对临床常见抗菌药物的耐药率存在一定差异性,非黏液型PA菌株毒力基因携带率较高。携带exoU毒力基因的PA菌株对临床常用抗菌药物的耐药率高于不携带exoU毒力基因的菌株。

Objective To explore the drug resistance of Pseudomonas aeruginosa(PA)and the distribution characteristics of its virulence genes,so as to provide a theoretical basis for the rational use of antibiotics in clinical practice and the development of new antibacterial drugs.Methods 316 strains of PA from different departments and sources of specimens submitted for clinical examination in the Third Affiliated Hospital of Xinxiang Medical College were selected.Antibiotic susceptibility testing was performed by the Kirby-Bauer method.The carrying status of virulence genes exoS and exoU was detected by PCR technology.Results Among the 316 strains of PA,95 strains were mucoid(30.06%),and 221 strains were non-mucoid(69.94%).Among mucoid PA,67 strains were from sputum(70.53%),14 strains were from wound secretions(14.74%),9 strains were from midstream urine(9.47%),and 5 strains were from blood(5.26%).Among non-mucoid PA,170 strains were from sputum(76.92%),22 strains were from wound secretions(9.95%),13 strains were from midstream urine(5.88%),and 16 strains were from blood(7.24%).Among mucoid PA,34 strains were from the respiratory department(35.79%),12 strains were from the burn department(12.63%),20 strains were from the ICU(21.05%),4 strains were from the neurology department(4.21%),4 strains were from the oncology department(4.21%),and 3 strains were from the hematology department(3.16%).and 18 strains were from other departments(18.95%).Among non-mucoid PA,110 strains were from the respiratory department(49.77%),33 strains were from the burn department(14.93%),22 strains were from the ICU(9.95%),21 strains were from the neurology department(9.50%),13 strains were from the oncology department(5.88%),and 11 strains are from the hematology department(4.98%)and 11 strains were from other departments(4.98%).There were significant differences in the composition ratios of the respiratory department,ICU,and other departments(P<0.05).For mucoid PA,the drug resistance to meropenem,imipenem,and amikacin was lower than 1o%,while the drug resistance to ceftazidime exceeds 30%.In addition,no strain resistant to polymyxin B had been found.For non-mucoid PA,its drug resistance to meropenem and imipenem was also lower than 10%,but the drug resistance to ceftazidime,levofloxacin,ciprofloxacin,and gentamicin exceeds 30%.Similarly,no strain was resistant to polymyxin B appears.Among different types of PA strains,the differences in drug resistance to meropenem,imipenem,gentamicin,and amikacin were statistically significant(P<0.05),while the differences in drug resistance to piperacillin/tazobactam,ceftazidime,cefepime,levofloxacin,and ciprofloxacin were not statistically significant(P>0.05).In mucoid PA,75 strains carried virulence genes,accounting for 78.95%.29 strains carried the(exoU+/exoS-)genotype,accounting for 30.53%,while 46 strains carried the(eroU-/eroS+)genotype,accounting for 48.42%.In addition,20 strains did not detect virulence genes,accounting for 21.05%.In non-mucoid PA,213 strains carried virulence genes,accounting for as high as 96.38%.Among them,88 strains carried the(ecoU+/eroS-)genotype,accounting for 39.82%,and 125 strains carried the(ecoU-/ecoS+)genotype,accounting for 56.56%.There were 8 strains without virulence genes detected,accounting for 3.62%.Comparing different types of PA strains,the difference in virulence gene carriage rate was statistically significant(P<0.05).The difference in carriage rate between the(eroU+/eroS-)genotype and the(eroU-/eroS+)genotype was not statistically significant(P>0.05).There were significant differences in the drug resistance rates of strains in the eroU+group(n=117)and the eroU-group(n=199)to piperacillin/tazobactam,meropenem,imipenem,levofloxacin,ciprofloxacin,and amikacin(P<0.05),while there was no significant difference in the drug resistance rates to ceftazidime,cefepime,and gentamicin(P>0.05).Conclusion PA strains were mainly non-mucoid,and which were mainly isolated from the respiratory department.Different types of PA strains had certain differences in the drug resistance rates to common clinical antibacterial drugs.The non-mucoid PA strains had a higher carrying rate of virulence genes.The drug resistance rate of PA strains carrying the eroU virulence gene to commonly used clinical antibacterial drugs was higher than that of strains not carrying the exoU virulence gene.