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Objective To investigate the pathogen distribution and susceptibility profile of fungal isolates from bloodstream infections,and valuate the clinical utility of G test in diagnosis of fungal infections for the purpose to improve antifungal therapy.Methods A retrospective analysis was carried out to analyze the fungal pathogens isolated from bloodstream infections in the First Affiliated Hospital of Nanjing Medical University during the period from January 2013 through December 2015 and their antimicrobial susceptibility.Results A total of 114 fungal strains were isolated from bloodstream infections during the 3-year period,most of which were Candida (99/114,86.8％),especially Candida albicans (30.7％).About 41.2％ (47/114) of the fungal strains were isolated from Department of Thoracic Surgery (10,5 and 4 strains in 2013,2014 and 2015),Hematology (11 strains in 2014),and ICU (7 strains in 2014).Antimicrobial susceptibility testing showed that all the fungal strains (100％) were susceptible to amphotericin B,but 83.5％ susceptible to itraconazole (the lowest).G test was positive before the result of blood culture in 13 of the 54 patients who received G test.Conclusions Candida was the most common fungus in fungal bloodstream infection.Amphotericin B is the most active antifungal agent in vitro.Blood culture combined with serological test can provide clinicians an earlier and reliable diagnosis.
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Objective Not much information is available on the comparative analysis of G test on diagnosis of deep fungal in -fection by colormetric and turbidimetric measurements .The purpose of this paper was to explore the clinical value of fungal (1-3)-β-D-glucan detection kit ( colormetric measurement ) . Methods 89 clinical samples collected from Hainan Branch of PLA General Hos-pital were detected by fungal (1-3)-β-D-glucan detection kit (turbidimetric measurement) and fungal (1-3)-β-D-glucan detection kit ( colormetric measurement ) respectively , among which 32 cases were from disease group ( deep fungal infection in patients ) and 57 ca-ses were from control group ( healthy person ) .The comparison was made on the sensitivity , specificity and accuracy of these two meth-ods. Results The sensitivity, specificity and accuracy of colormetric measurement kit on the diagnosis of deep fungal infection were obviously higher than those of turbidimetry method kit (81.2%vs 53.1%, 91.2%vs 75.4%, 87.6%vs 67.4%, P<0.05), which was of significant difference .Detection result of colormetric method had a positive coincidence rate with other systems '( except respira-tory system) deep fungal infection, which was obviously higher than turbidimetry method (92.8%vs 57.1%, P<0.05).Positive co-incidence rate and total coincidence rate between colormetric method kit and clinical diagnosis result on differentiate samples were obviously higher than those of turbidimetric method kit (P=0.01). Conclusion Colormetric measurement kit has higher accuracy and higher coincidence rate with clinical diagnosis than turbidimetry meas-urement kit , which is better for clinical service .
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Objective To explore the clinical value of plasma(1,3)-β-D-glucan detection(G test)in the diagnosis of invasive fun-gal infections(IFI).Methods The plasma samples were collected in 67 cases of IFI,61 cases of non-IFI and 48 healthy controls from January to September 2013.The level of(1,3)-D-glucan in plasma was detected by the kinetic turbidimetric assay and the opti-mal critical value of the G test was determined by receiver operating characteristic curve(ROC).Results The levels of(1,3)-β-D glucan in the IFI,non-IFI and healthy control groups showed the non-normal distribution.However,the median level of plasma(1, 3)-β-D glucan in the IFI group was 208.00pg/mL,which was significantly higher than 61.30 pg/mL(Z =-5.083,P <0.01)in the non-IFI group and 31.16 pg/mL(Z =-8.288,P <0.01)in the healthy control group.The area under ROC of the G test for diag-nosing IFI was 0.846 and the optimal critical value was 90.49pg/mL.The corresponding sensitivity,specificity,positive and nega-tive predictive values were 86.6%,77.1%,69.9% and 90.3%,respectively;at the same time,which of the fungal culture for diag-nosing IFI were 53.7%,94.5%,85.7% and 61.9% respectively.Conclusion Plasma(1,3)-β-D-glucan detection exhibits the high sensitivity and the better negative predictive value for the diagnosis of IFI.But the false positive results occur at times.It is sugges-ted that the G test can be dynamically conducted combined with the fungal culture for improving the efficiency of IFI diagnosis.
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Objective To investigate the mechanism of soluble β-1, 3-D-glucan in G-test positive serum in inhibiting ROS-dependent killing of Candida albicans ( C.albicans ) mediated by neutrophil Dectin-1.Methods The expression and distribution of internalized Dectin-1 and triggered ROS in human neutrophils were detected by using confocal/two-photon laser scanning microscopy upon stimulation with C.albicans (MOI=10) which was pretreated with β-1, 3-D-glucanase (10 U/ml) or not.Abrogation test was used to analyze whether intracellular Dectin-1 was involved in C.albicans-triggered ROS production in human neutrophils.Furthermore, flow cytometry analysis was performed to detect the expression of intracel-lular Dectin-1 and ROS in neutrophils which were pretreated respectively with G-test positive serum at differ-ent dilutions for 60 min and then stimulated with C.albicans for another 60 min at 37℃.Results After stimulated with C.albicans (MOI=10) for 60 min, the expression of Dectin-1 in neutrophils was recruited to the spores of opsonophagocytized C.albicans, and partly co-localized with the triggered ROS production . However, the expression of intracellular Dectin-1 was not observed in neutrophils when stimulated with β-1, 3-D-glucanase pretreated C.albicans for 60 min at 37℃.Abrogation test further showed that C.albicans-trig-gered ROS production in neutrophils was partly and irreversibly inhibited by adding Dectin -1 blocking mAb of 5 μg/ml.In addition , both the triggered expression of intracellular Dectin-1 and ROS production in neu-trophils stimulated with C.albicans ( MOI=10 ) in the presence of G-test positive serum were significantly lower than those of neutrophils stimulated only with C.albicans (LSD-t test, P<0.01).Linear regression a-nalysis suggested that the triggered intracellular Dectin-1 and ROS production in neutrophils upon stimulation with C.albicans were both inhibited by soluble β-1, 3-D-glucan in a dose-dependent manner (Dectin-1,R2=0.702,P<0.01;ROS,R2=0.588,P<0.01 ).Conclusion Taken together, these results demonstrated that the soluble β-1, 3-D-glucan in G-test positive serum may play a role in inhibiting the ROS-dependent killing of C.albicans by interfering with internalized expression of neutrophil Dectin-1.