ABSTRACT
Objective:To investigate the value of procalcitonin (PCT),C-reactive protein (CRP) in discriminating the bloodstream infection bacterial species,and to analyze the levels of PCT and CRP in sepsis caused by different pathogens.Methods:Patients with blood culture and PCT,CRP detection were collected in the study,from January 2015 to January 2017.The levels of PCT and CRP were detected with electrochemiluminescence and immunoturbidimetric,respectively.The levels of PCT in gram positive bacteria and gram negative bacteria,different bacterial species were compared by SPSS21.0 statistical software.Receiver operating characteristic(ROC) curve was established by Sigma software,calculating the optimal cutoff value.Results:The difference in the levels of PCT between gram positive bacteria and gram negative bacteria was statistically significant,and the value of U was 4 420.00,(P=0.004).ROC analysis showed the optimal cut-off value was 1.105 ng/ml.The levels of PCT had statistically significant difference in coagulase-positive staphylococci and coagulase-negative staphylococci,and the value of U was 79.00(P<0.001).ROC analysis revealed the optimal cut-off value of 0.870 ng/ml.There was a significant difference in the levels of PCT in Enterobacteriaceae and non fermentative bacteria and the value of U was 681.50(P=0.005).ROC analysis showed the optimal cutoff value was 3.310 ng/ml.There was no significant difference in PCT between Staphylococcus and Enterococcus.The levels of CRP was no significant difference between the groups.Conclusion:Detection of PCT has certain value in discriminating of bloodstream infection by different bacterial species,which can provide the basis for the early rational use of drugs in patients with suspected bacteremia.The detection of PCT combined with the blood culture,can reduce the risk of failure in patients with severe infection,and improve the efficiency of treatment.
ABSTRACT
Objective To investigate the feasibility of modified rapid Carba NP test for the detection of carbapenemase,and analyze the differences between the modified method and Carba NP test.Methods A total of 264 strains of gram-negative bacillus,including 164 carbapenem-resistant strains and 100 sensitive strains,were collected,and their carbapenemase were detected by Carba NP test and the modified rapid Carba NP test,respectively.The differences between the two tests were evaluated based on PCR as a reference.Results Among 164 carbapenem-resistant strains,carbapenemase gene was detected in 144 strains by PCR.The carbapenemase gene was negative in 100 sensitive strains.Among 164 carbapenem-resistant strains,135 were positive for the Carba NP test,while 130 for the modified rapid Carba NP test.One hundred of sensitive strains were negative for the two Carba NP tests.Compared with the results of PCR,the sensitivity,specificity and Kappa value of the Carba NP test were 91.7％ (132/144),97.5％ (117/120) and 0.886,respectively,while those of the modified rapid Carba NP test were 89.6％ (129/144),99.2％ (119/120) and 0.879,respectively.There was no significant difference in the positive rates between Carba NP test and the modified rapid Carba NP test (x2 =1.45,P ＞ 0.05).Conclusion The modified rapid Carba NP test which has high consistency with the PCR method,is faster and cheaper than the Carba NP test,and may be applied to epidemiologic survey and the early monitoring of nosocomial infections.
ABSTRACT
Objective To evaluate the application value of inhibitor enhanced modified carbapenemase inactivation method (imCIM) in the detection of class B carbapenemase.The differences between imCIM and EDTA disc potentiation test (EDPT) were comparatively analyzed.Methods A total of 181 strains of carbapenem insensitive strains were collected,among which there were 44 strains of Klebsiella pneumoniae,44 strains of Escherichia coli,43 strains of Acinetobacter baumannii and 50 strains of Pseudomonas aeruginosa.The 83 strains of carbapenem-sensitive strains were composed of 25 strains of Klebsiella pneumoniae,16 strains of Escherichia coli,25 strains of Acinetobacter baumannii and 17 strains of Pseudomonas aeruginosa.The class B carbapenemase in the 264 strains of pathogenic bacteria was screened by imCIM and EDPT,and PCR results were used as gold standard.The statistical analysis wasperformed with consistency check,related-sample Wilcoxon signed rank sum test,independent samples Kruskal-Wallis H test and ROC curve.Results Among the 181 strains of carbapenem insensitive strains,PCR results of 144 strains were positive for drug resistance gene.The samples of class A,B and D of carbapenemase were 39,77 and 28 strains respectively.The results of imCIM showed that 70 strains were positive,and the other 111 strains were negative.The imCIM results of 166 strains were consistent with those of PCR.The results of EDPT showed that 72 strains were positive,and the other 109 strains were negative.The EDPT results of 134 strains were consistent with those of PCR.The results of PCR,EDPT and imCIM of 83 carbapenem sensitive strains were negative.The sensitivity and specificity of imCIM were 85.71％ (66/77) and 97.86％ (183/187),and the value of Kappa was 0.859.The sensitivity and specificity of EDPT were 66.23 ％ (51/77) and 88.77 ％ (166/187),and the value of Kappa was 0.561.The difference of inhibition zone of imCIM (AdimCIM) was different from EDPT(AdEDPr) and the difference was statistically significant (Z =-6.941,P ＜ 0.05).In the imCIM detection,the AdimciM level of class B carbapenemase showed different population distribution position from class A and D carbapenemase with the statistically significant difference (x2 =108.887,P ＜ 0.05).The areas under the ROC curve of imCIM and EDPTwere 0.988 (95％CI:0.977 to0.999) and0.936 (95％CI:0.909 to0.963),respectively.Conclusion imCIM should be accurate,efficient and convenient for screening of carbapenem phenotype for its high sensitivity and specificity,and suitable for epidemiological monitoring.