ABSTRACT
Objective To investigate the distribution of hypervirulent capsular serotypes and virulence genes of Klebsiella pneumoniae associated with pyogenic liver abscess(PLA),and analyze the homology of strains.Methods Twelve strains of liver abscess-related Klebsiella pneumoniae were isolated in Wuxi Second People's Hospital during January 2016 and August 2017.Among them,five were also detected in blood samples.All the strains were performed the viscous thread test,and the hypervirulent capsular serotypes and main virulence genes were detected by PCR.The homology of the strains was analyzed by the multilocus sequence types(MLST) and pulsed-field gel electrophoresis(PFGE).Results The positive rate of the viscous thread test for 12 strains of liver abscess-related Klebsiella pneumoniae was 75％.Three kinds of hypervirulent capsular serotypes,including K1 (6/12,50％),K54(1/12,8.3％) and K57(5/12,41.7％),were detected.The positive rates of virulence genes,such as wcaG,rmpA,ureA,fimH,mrkD,uge,Aer and iroNB,were all 100％,while that of iucB was 83.3％.The cf29a gene was not found,and the magA,allS and kfuBC genes were only detected in K1 serotype strains.MLST found that ST23(4/12,33.3％) and ST25(3/12,25％) were main sequence types,and then were ST412(2/12,16.7％),ST1660(1/12,8.3％),ST1049(1/t2,8.3％) and ST11 (1/12,8.3％).PFGE showed that 12 strains of Klebsiella pneumoniae were divided into 8 types,and that only 3 strains of K1 serotype belong to the same clonotype.Conclusion All the isolated liver abscess-related Klebsiella pneumoniae strains are highly virulent.ST23 and ST25 are main sequence types,and ST1049 is first reported.PFGE results show genetic diversity,and Kl-type Klebsiella pneumoniae has a certain epidemic tendency.
ABSTRACT
Objective To evaluate the early diagnostic value of the detection of plasma 1,3-β-D glucan(G test) for deep mycobacterium infection and assess the difference of the G test and fungal culture.Methods We collected test plasma from 420 subjects from January to November 2014,including 226 cases of deep mycobacterium infection,88 cases of non-fungal infection and 106 cases of healthy controls.G-test was used to measure the concentration of 1,3-β-D glucan in the plasma.The cut-off points for 1,3-β-D glucan were determined by using receiver operator characteristics curves(ROC).Results The concentration of 1,3-β-D in plasma of paients with deep mycobacterium infection was significantly higher than that of patients with non-fungalinfection and healthy controls.There was no difference between the control groups.With the analysis of ROC curve,the best cut-off value was 25.33 pg/mL.The sensitivity,specificity,positive predictive value and negative predictive value of G test were 84.9%,70.83%,72.0%,84.1%(P<0.05).Conclusion G Test is a practical and effective method in early diagnosis of deep fungal infection.
ABSTRACT
OBJECTIVE To develop a suitable and easy method for detecting AmpC ?-lactamases.METHODS The function with different cloxacillin concentrations in cloxacillin-potentiated disc diffusion test was compared and estimated with FOX three-dimensional extract test to show the best concentration of cloxacillin.RESULTS Cefoxitin three-dimesional test indicated that 48 strains were detected out to produce AmpC ?-lactamases among 130 clinical isolates of Gram-negative bacilli strains.when the discs contained 200 ?g cloxacillin the CAZ,CTX,CRO and ATM alone could separately detect 87.5%,87.5%,87.5% and 33.3% highly producing AmpC ?-lactamases strains.When the combination of CTX with CRO,almost 95.8% could be detected out.CONCLUSIONS With the combination of CTX and CRO,the cloxacillin-potentiated disc diffusion test can specifically detect AmpC ?-lactamases and easy to be used in clinical laboratories.