The Role Of T Lymphocyte Subsets And Cytokines In The Identification Of Acinetobacter Baumannii Colonization And Infection

ObjectiveTo investigate the colonization and infection of Acinetobacter baumannii(A.baumannii)using T lymphocytes subsets and serum cytokines.MethodsA total of 109 patients who had A.baumannii in sputum were collected during January 2016 to November 2016 from the first Affiliated Hospital of Wannan Medical College,All patients were divided into colonization group(53cases)and infection group(56 cases)according to the diagnostic criteria of hospital-acquired pneumonia by Respiratory Society,Chinese Medical Association.50 cases from normal physical examination were collected as control group.The bacterial identification and drug susceptibility of A.baumannii were detected by VITEK2 Compact automatic bacterial detection instrument,using K-B method to verify drug sensitivity results.The proportion of CD3~+,CD4~+and CD8~+of T lymphocyte subsets in each group were detected by flow cytometry.The levels of cytokines were detected by enzyme-linked immunosorbent assay(ELISA),and the differences among groups were compared.The difference in groups with different age,sex and drug resistance were also been analyzed.The factors of T lymphocyte subsets or cytokines were analyzed by Spearman correlation analysis.Logistic regression analysis was used for investigating the predictors for the infection of A.baumannii.ResultsThere are 67 males(61.47%)and 42 females(38.53%)had A.baumannii.The ages of most patients were older than 60 years.The drug susceptibility of A.baumannii was serious,of which ampicillin resistance rate was98.16%and cefotetan resistance rate was 99.08%.Aztreonam,ceftizoxime,ampicillin sulbactam,ciprofloxacin,imipenem,tobramycin also appeared more than 60%resistance rate,resistant to three types of drugs in 41 cases,accounting for 37.61%of Acinetobacter baumannii,resistant to all the tested drugs in 29cases,accounting for 26.61%of Acinetobacter baumannii.Between colonization group and infection group,the significant differences were been found in T lymphocytes subsets,TNF-α、IFN-γand IL-17.The A.baumannii infection was positively associated with TNF-α(r_s=0.241,P=0.012),IFN-γ(r_s=0.235,P=0.014),IL-2(r_s=0.249,P=0.009),IL-4(r_s=0.268,P=0.005)and IL-17(r_s=0.538,P=0.000),whereas which was negatively associated with CD3~+(r_s=-0.193,P=0.045)and CD4~+/CD8~+(r_s=-0.302,P=0.001).Multi-factor Logistic regression analysis showed that IFN-γand IL-17 could be the identification index of acinetobacter baumannii colonization and infection.ConclusionThe levels of TNF-α,IFN-γand IL-17 in colonization group were also higher than that in control group.The levels of IL-2 and IL-4 in the infection group and the colonization group were higher than those in the control group.There was no significant difference between infection group and colonization group.Acinetoba- cter baumannii infection was positively correlated with TNF-α,IFN-γ,IL-2,IL-4and IL-17,but was negatively correlated with CD3~+and CD4~+/CD8~+.Multi-factor Logistic regression analysis showed that IFN-γand IL-17 could be used as the factors to identify Acinetobacter baumannii infection or colonization,and provide a basis for rational use of antimicrobial agents and prevention and control of nosocomial infections.