| Objective:To investigate the distribution,antibiotic resistance and virulence genes of carbapenem resistant Pseudomonas aeruginosa(CRPA)strains isolated from samples of hospitalized patients and the clinical characteristics of these patients,and to further explore the correlation between CRPA related virulence genes with bacterial infection and colonization,in order to evaluate the clinical value of CRPA related virulence gene in distinguishing infection and colonization.Methods:Pseudomonas aeruginosa isolates were isolated from Clinical samples collected from hospitalized patients between June 201 8 to August 2019.The strains resistant to imipenem or meropenem were determined as CRPA by drug sensitivity test.The strains were divided into two groups: infection and colonization.Virulence genes were detected using polymerase chain reaction(PCR).Clinical data of the CRPA-detected patients were retrospectively studied.Results:1.A total of 612 Pseudomonas aeruginosa strains were isolated during the study period,of which CRPA172 strains were detected,with a detection rate of 28.1%.A total of 141 CRPA strains were included in the group,with the highest proportion of sputum samples(70.9%),of which the proportion of sputum samples in the colonization group was 94.1%.2.There was no significant statistical difference observed between two groups in clinical characteristics such as age,gender,smoking history and clinical stay.However,significant statistical differences were observed in clinical characteristic including lung function,antibiotic use,frequency of tracheal intubation and venti lator use,and plasma globulin level(p < 0.05).3.The overall drug resistance rate of CRPA was higher,with the multiple drug resistance rate at 51.8%,and the extensive drug resistance rate at 29.7%.The extensive drug resistance rate of the colonizatio n group was found to be remarkable higher than the infection group,in which the difference is statistically significant(P < 0.05).4.The total detection rates of exoU,exoS,LasR,LasI and Hcp2 genes were 66.7%,47.5%,90.0%,87.9% and 77.3% respective ly.The positive rates of exoU,exoS and Hcp2 genes compared between the colonization group and the infection group were statistical different(P < 0.05).ExoS gene was identified as the main gene in the colonization group,with a positive rate of 66.7%.On the other hand,exou and hcp2 genes were identified as the main genes in the infection group,with a positive rate of 77.8% and 91.1%,respectively.5.The expression rate of(exoU-/ exoS+)in the colonization group was 45.1%,which was obviously higher than the infection group(12.2%)(P < 0.05).The expression rate of(exoU + / exoS-)in the infection group was 53.3%,which was significantly higher than the colonization group(25.5%)(P < 0.05).6.The expression rate of virulence genotype(exoU+ / exoS-)in MDR was 49.3%,which is significantly higher than XDR(23.8%),P < 0.05.On the contrary,the expression rate of(exoU+ / exoS+)in XDR was 42.9%,which is significantly higher than MDR(15.1%)(p<0.05).Conclusion:1.The detection rate of CRPA in our hospital is high,which is mainly detected from the sputum samples.Although certain proportion of the colonized bacteria were detected,no pan resistant strains were found,Nevertheless,the phenomenon of extensive resis tance and multiple resistance in hospital is serious.2.Compared to the infectious bacteria,the colonized bacteria are less toxic,but more resistant to drug and more extensive.Of note,the colonized bacteria may transformed into highly resistant pathogenic bacteria when the conditions such as the acceptance of invasive operation and the reduction of plasma globulin are met.3.The positive rates and the expression types of some virulence genes in the colonized and infectious bacteria were found to be statistically significant,which presumes that there was certain correlation between gene expression types and drug resistance.4.The detection of CRPA related virulence genes poses certain diagnostic value in differentiating between clinical colonization and infection,and has certain guiding significance to analyze the clinical characteristics and treatment outcome of patients. |
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