1.Difference in susceptibility of carbapenem-resistant Klebsiella pneumoniae to tigecycline detected by MTS and instrumental MIC assay
Liqin ZHANG ; Cong LIU ; Jiuchang XIAO ; Shuhui ZOU
Chinese Journal of Infection Control 2017;16(9):845-848,869
Objective To explore clinical distribution characteristics of carbapenem-resistant Klebsiella pneumoniae (CRKP), analyze enzyme production of strains and verify the in vitro antimicrobial activity of tigecycline.Methods Antimicrobial susceptibility testing results of 53 strains of CRKP isolated from clinical specimens of patients in a hospital from January to December 2015 were analyzed, carbapenemase production of target strains was detected by modified Hodge test, metallo-β-lactamase was detected by EDTA synergy test, minimum inhibitory concentration(MIC) of tigecycline susceptibility testing result detected by instrument was confirmed by MIC test strip(MTS method).Results 53 CRKP strains were mainly isolated from patients in intensive care unit (n=14, 26.42%) and burn unit(n=13, 24.53%);sputum(n=23, 43.40%) and wound secretion(n=15, 28.30%) were the main specimen sources;isolation rate of CRKB was highest in the elderly≥60 years old, 35 strains(66.04%)of CRKP were isolated.CRKP was most sensitive to tigecycline(96.2%).The modified Hodge test showed that 48 strains(90.6%) produced carbapenemases and 15 strains produced metallo-β-lactamase.MICs of tigecycline-resistant strains detected by instrument were all confirmed as susceptibility by MTS.Conclusion CRKP mainly produce carbapenems in this hospital, some strains can produce two types of different β-lactamases;antimicrobial susceptibility testing showed that tigecycline has good antimicrobial activity against CRKP, tigecycline-resistant strains detected by instrument must be confirmed by MTS method.
2.Application analysis of time-resolved fluorescence immunoassay technology in syphilis specific antibody screening
Wei DAI ; Shiyun LI ; Dejun XIAO ; Ting LIU ; Jiuchang XIAO ; Jing LI
International Journal of Laboratory Medicine 2015;(21):3117-3118
Objective To investigate the application of time‐resolved fluorescence immunoassay (TRFIA) in the detection of specific antibody of syphilis .Methods Specific antibody of syphilis was detected in serum samples of 240 cases of syphilis and 150 healthy subjects by TRFIA ,Treponemal pallidum particle agglutination(TPPA) and Treponemal pallidum enzyme linked immu‐nosorbent assay(TP‐ELISA) .The sensitivity ,specificity and positivity of these three methods were compared .Results The sensi‐tivity of TRFIA ,TP‐ELISA ,TPPA were 100 .00% ,98 .75% and 97 .92% ,without significantly differences(P>0 .05) ,and the spe‐cificity were 99 .33% ,98 .67% and 100 .00% .The false positive rate of TRFIA was 0 .67% ,and the false negative rate was 0 .00% . The false positive rate of TP‐ELISA was 1 .33% ,and the false negative rate was 1 .25% .False positive rate and false negative rate of TRFIA were lower than TP‐ELISA(P<0 .05) .Conclusion TRFIA could be with high sensitivity and specificity in syphilis spe‐cific antibody test ,and could be used for routine screening of syphilis specific antibody .