Inhibition mechanism of cordycepin and ergosterol from Cordyceps militaris Link. against xanthine oxidase and cyclooxygenase-2

Cordyceps militaris Link. (C. militaris) is an entomopathogenic fungus that parasitizes the pupa or cocoon of lepidopteran insect larvae, with various bioactive compounds. Cordycepin and ergosterol are the two active components in C. militaris. This study aimed to evaluate the inhibitory activity of cordycepin and ergosterol against xanthine oxidase (XO) and cyclooxygenase-2 (COX-2), as well as investigate the inhibition mechanism. Cordycepin could better inhibit XO (IC50 = 0.014 mg/mL) and COX-2 (IC50 = 0.055 mg/mL) than ergosterol. Additionally, surface hydrophobicity and circular dichroism (CD) spectra results confirmed the conformational changes in enzymes induced by cordycepin and ergosterol. Finally, cordycepin and ergosterol significantly decreased uric acid (UA) and inflammatory factors to normal level in mice with gouty nephropathy (GN). This study could provide theoretical evidence for utilization of C. militaris in hyperuricemia-management functional foods.

Rapid detection of respiratory organisms with FilmArray respiratory panel and its impact on clinical decisions in Shanghai, China, 2016-2018

BACKGROUND

In this study, we evaluated the diagnostic potential and clinical impact of an automated multiplex PCR platform (the FilmArray Respiratory Panel; FA-RP), specially designed for pathogen detection in respiratory tract infections in adults with unexplained pneumonia (UP).

METHODS

A total of 112 UP patients in Shanghai, China, were enrolled prospectively and assessed using the FA-RP from October 2016 to March 2018. We examined the test results and their influence on clinical decisions. Furthermore, as a control group, we retrospectively obtained the clinical data of 70 UP patients between October 2014 and March 2016 (before the FA-RP was available). The two patient groups were compared with respect to factors, including general antimicrobial use and defined daily dose (DDD) numbers.

RESULTS

Between October 2016 and March 2018, the positive rate obtained using FA-RP for UP was 76.8%. The primary pathogens in adults with UP were Influenza A/B (47.3%, 53/112). Compared with the patients before FA-RP was available, patients who underwent FA-RP testing had higher rates of antiviral drug use and antibiotic de-escalation during clinical treatment. FA-RP significantly decreased the total DDDs of antibiotic or antifungal drugs DDDs by 7 days after admission (10.6 ± 2.5 vs 14.1 ± 8.8, P < .01).

CONCLUSIONS

The FA-RP is a rapid and sensitive nucleic acid amplification test method for UP diagnosis in adults. The application of FA-RP may lead to a more accurately targeted antimicrobial treatment and reduced use of antibiotic/antifungal drugs.

Late prosthetic valve endocarditis with Mycobacterium tuberculosis after the Bentall procedure

Background

Prosthetic valve endocarditis (PVE) is a rare but severe complication of valve replacement surgery, with an incidence rate of 0.3–1.2% per patient-year. At present, staphylococci are the predominant causative microorganism of PVE. Herein, we report a confirmed case of late PVE in a mechanical aortic valve caused by Mycobacterium tuberculosis.

Case presentation

A 32-year-old immunocompetent man with recurrent fever and 5-kg weight loss had a history of having undergone the Bentall procedure due to congenital heart disease. Nine years after the operation, he developed a paravalvular abscess in the mechanical aortic valve, presented with evidence of pulmonary tuberculosis on CT scan and was diagnosed with tuberculous endocarditis. This case report highlights a rare and non-negligible example of tuberculous endocarditis involving a mechanical valve.

Conclusions

Tuberculous PVE should be considered in patients with a history of valve replacement, recurrent fever, unexplained weight loss, pulmonary tuberculosis and meaningful valvular findings on echocardiogram.

Cytokine profiles in cerebrospinal fluid of patients with meningitis at a tertiary general hospital in China

BACKGROUND

There has been a great deal of evidence indicating that cytokines participate in meningeal inflammation. Different cytokine profiles may be presented in central nervous system (CNS) infection due to different pathogens. We have attempted to investigate cytokine profiles in cerebrospinal fluid (CSF) of patients with CNS infection.

METHODS

Forty-three patients with CNS infection including tuberculous meningitis, purulent meningitis and cryptococcal meningitis were enrolled and 11 patients with normal CSF were enrolled as control group. The concentrations of Th1-, Th2- and Th17-type cytokines in CSF were detected using multiplex cytokine assay. Furthermore, the correlation between CSF cytokines and CSF parameters in CNS infection was analyzed.

RESULTS

The CSF levels of IL-1β, IL-4, IL-6, IL-10, IL-17, IL-23, IL-33, IFN-γ, TNF-α and sCD40L among the patients with CNS infection were all higher than control group (all P < 0.05). A remarkable elevation of CSF IL-6 in the patients with CNS infection was observed with the least overlap of the CSF concentrations compared to controls. Moreover, CSF IL-6 levels were strongly negatively correlated with CSF glucose and the CSF/blood glucose ratio (r = -0.4375, P = 0.0042; r = -0.4991, P = 0.0009).

CONCLUSIONS

The excessive activation of immune response characterized by elevated levels of CSF Th1-, Th2- and Th17-type cytokines has been observed during CNS infection. Furthermore, we observed negative correlations between CSF IL-6 levels and CSF glucose and CSF/blood glucose ratio in CNS infection. And we suggested that combined CSF IL-6 levels with CSF glucose may serve as a novel biomarker pool for the differential of CNS infection.

The expressions and roles of different forms of IL-22 in Mycobacterium tuberculosis infection

Despite evidence suggesting an anti-Mycobacterium tuberculosis effector function of CD4+ T cells that produce and retain IL-22 in macaques, the general role of IL-22 in tuberculosis infection is still poorly characterized. To explore the immune mechanism in the pathogenesis of tuberculosis in humans, here we evaluated different forms of IL-22 in populations with different tuberculosis infection statuses. We enrolled 156 subjects including 49 patients with pulmonary tuberculosis, 27 patients with tuberculous pleurisy (TPE), 38 individuals with latent tuberculous infection (LTBI) and 42 healthy controls (HC). We found significantly higher IL-22 levels at the tuberculosis infection site than in the peripheral blood as well as higher antigen-specific IL-22 levels in the culture supernatant for patients with active tuberculosis than in healthy controls. The proportions of IL-22 + CD4+ T and IL-22 + CD8+ T cells in patients with active tuberculosis were significantly higher than those in the latent tuberculosis infection group and the healthy control group, based on intracellular cytokine staining. However, surprisingly, we found membrane-bound IL-22+ T cells, including CD4+ T cells and CD8+ T cells, by surface staining, especially in patients with active tuberculosis. Furthermore, the expression of membrane-bound IL-22 significantly decreased after drug therapy. In conclusion, our results suggest that IL-22 has various roles in tuberculosis immune responses. In particular, membrane-bound IL-22+ T cells may play important roles in the human immune response to Mycobacterium.

[Clinical efficacy and safety of vancomycin compared with linezolid for the treatment of neonatal gram-positive bacterial sepsis]

OBJECTIVE

To evaluate the clinical efficacy and safety of vancomycin and linezolid for the treatment of gram-positive neonatal bacterial sepsis.

METHOD

The data of neonates diagnosed as gram-positive bacterial sepsis in neonatology department of Suzhou Municipal Hospital from June 2009 to December 2015 were retrospectively collected. These neonates were divided into vancomycin group and linezolid group. Propensity score matching (PSM) on baseline variables was used to balance the two groups by identifying a comparable group of neonates who received vancomycin and linezolid therapy. Clinical and microbiologic success rates were compared by chi-square test, and changes of laboratory parameters before and after treatment at the end of treatment were then directly compared by rank-sum test between the matched groups. In vancomycin group, correlation between trough concentration of vancomycin and clinical efficacy were evaluated.

RESULT

Totally 108 and 209 cases were respectively selected in vancomycin and linezolid groups; 108 cases with well-matched baseline characteristics were included in matched linezolid group. The clinical success rates of vancomycin vs. linezolid therapy were 86.1%(93/108) and 88.9%(96/108)(P=0.681), and the microbiologic success rates were 91.7%(99/108) and 93.5%(101/108)(P=0.795). The average trough concentration of vancomycin was (12±8) mg/L. The rate of reaching the high trough concentration standard was only 33.3%(36/108). In 50 (46.3%) cases the dose was adjusted according to the initial concentration data. Compared to less than 10 mg/L, the clinical efficacy of trough concentration in 10-20 mg/L was much higher(93.9%(46/49) vs. 78.6%(33/42), P=0.031). Total bilirubin and platelet count had significant difference between the two-matched groups (34.1(14.9, 91.0)μmol/L vs. 53.0(27.0, 121.6)μmol/L, P=0.034; 301.0(198.8, 416.0)×10(9)/L vs. 195.5(94.0, 283.2)×10(9)/L, P=0.000). The incidence of linezolid related thrombocytopenia was 13.4%(28 cases).

CONCLUSION

The clinical effect of vancomycin and linezolid on gram-positive bacterial sepsis in neonates is comparable. The rate of trough concentration of vancomycin reaching the high trough concentration standard is low, and the clinical efficacy is related to trough concentration. Linezolid have an effect on bilirubin and platelet count, the risk of thrombocytopenia should be monitored closely during linezolid treatment.

A combination of the QuantiFERON-TB Gold In-Tube assay and the detection of adenosine deaminase improves the diagnosis of tuberculous pleural effusion

The differential diagnosis of tuberculous pleural effusion (TPE) and malignant pleural effusion (MPE) remains difficult despite the availability of numerous diagnostic tools. The current study aimed to evaluate the performance of the whole blood QuantiFERON-TB Gold In-Tube (QFT-GIT) assay and conventional laboratory biomarkers in differential diagnosis of TPE and MPE in high tuberculosis prevalence areas. A total of 117 patients with pleural effusions were recruited, including 91 with TPE and 26 with MPE. All of the patients were tested with QFT-GIT, and the conventional biomarkers in both blood and pleural effusion were detected. The level of antigen-stimulated QFT-GIT in the whole blood of TPE patients was significantly higher than that of MPE (2.89 vs 0.33 IU/mL, P<0.0001). The sensitivity and specificity of QFT-GIT for the diagnosis of TPE were 93.0% and 60.0%, respectively. Among the biomarkers in blood and pleural effusion, pleural adenosine deaminase (ADA) was the most prominent biomarker, with a cutoff value of 15.35 IU/L. The sensitivity and specificity for the diagnosis of TPE were 93.4% and 96.2%, respectively. The diagnostic classification tree from the combination of these two biomarkers was 97.8% sensitive and 92.3% specific. Ultimately, the combination of whole blood QFT-GIT with pleural ADA improved both the specificity and positive predictive value to 100%. Thus, QFT-GIT is not superior to pleural ADA in the differential diagnosis of TPE and MPE. Combined whole blood QFT-GIT and pleural ADA detection can improve the diagnosis of TPE.

Characterization of CD4/CD8+ αβ and Vγ2Vδ2+ T cells in HIV-negative individuals with different Mycobacterium tuberculosis infection statuses

BACKGROUND

The immune responses of T cell subsets among patients with different Mycobacterium tuberculosis (M.tb) infection statuses [i.e., active tuberculosis (ATB), latent tuberculosis infection (LTBI) and non-infection (healthy control, HC)] have not been fully elucidated in HIV-negative individuals. Specifically, data are limiting in high tuberculosis epidemic regions in China. To investigate the distributions and functions of T cell subsets (i.e., CD3+, CD4+, CD8+ αβ and Vγ2Vδ2+ T cells) in HIV-negative subjects with different M.tb infection statuses, we conducted a case-control study that enrolled 125 participants, including ATB patients (n = 46), LTBI subjects (n = 34), and HC (n = 45).

RESULTS

An IFN-γ release assay (IGRA) was employed to screen LTBI subjects. Whole blood cell surface staining and flow cytometry were used to detect phenotypic distributions of T cells in the peripheral blood mononuclear cells (PBMCs) and tuberculous pleural fluid mononuclear cells (PFMCs). PPD and the phosphorylated antigen HMBPP were employed as stimulators for the detection of M.tb antigen-specific T cell functions via intracellular cytokine staining (ICS). The absolute numbers of T cell subsets, including CD3+ CD4+, CD3+ CD8+ αβ and Vγ2Vδ2+ T cells, were significantly reduced in active tuberculosis compared with latent tuberculosis or the healthy controls. Importantly, PPD-specific CD3+ CD4+ and CD3+ CD8+ αβ T cells and HMBPP-specific Vγ2Vδ2+ T cells in ATB patients were also significantly reduced compared to the LTBI/HC subjects (P<0.05). In contrast, the proportion of CD4+ T cells in PFMCs was higher compared to PBMCs, while CD8+ and Vγ2Vδ2+ T cells in PFMCs were lower compared to PBMCs (all P < 0.05). PPD-specific CD4+ T cells predominated among CD3+ T cells in PFMCs.

CONCLUSIONS

Cellular immune responses are impaired in ATB patients. Antigen-specific CD4+ T cell may migrate from the periphery to the lesion site, where they exert anti-tuberculosis functions.

[Long-term treatment of chronic hepatitis B]

Nucleoside and nucleotide analogs (NAs) have been successfully used for treatment of chronic hepatitis B. Hepatitis B virus (HBV) replication is now recognized as the key driver of liver injury and disease progression, so the primary aim of treatment for chronic HBV infection is to maximize sustained suppression of HBV replication to undetectable levels. The long-term treatment has also been shown to achieve substantial histological improvement and regression of liver fibrosis or cirrhosis, and reduction of hepatocellular carcinoma. This paper has reviewed the necessity, clinical benefits, and the management of long-term treatment for chronic hepatitis B.

Validation of thwaites' diagnostic scoring system for the differential diagnosis of tuberculous meningitis and bacterial meningitis

To compare the clinical features of patients with tuberculous meningitis (TBM) and bacterial meningitis (BM) and to validate Thwaites' diagnostic scoring system for the differential diagnosis of TBM and BM, a retrospective review of 211 patients with TBM or BM who were admitted to Huashan Hospital, Fudan University, from 2007 to 2012 was conducted. The clinical characteristics and laboratory data were compared, and Thwaites' diagnostic scores were assessed at the time of admission for the differential diagnosis of TBM and BM. Significant differences were observed between the 2 groups in general information, clinical features, and cerebrospinal fluid characteristics. The sensitivity and specificity of Thwaites' diagnostic scoring system for the differential diagnosis of TBM and BM were found to be 98.2% and 43.6%, respectively, with positive and negative predictive values being 65.9% and 95.8%, respectively. The sensitivity and specificity for the differential diagnosis of TBM and initially treated BM were 98.2% and 82.9%, respectively, but were only 98.2% and 24.2% for that of TBM and partially treated BM, respectively. Thus, Thwaites' diagnostic scoring system was found to be highly effective for the differential diagnosis of TBM and initially treated BM but was found to be less effective for that of TBM and partially treated BM.

Aspartate decarboxylase (PanD) as a new target of pyrazinamide in Mycobacterium tuberculosis

Pyrazinamide (PZA) is a frontline anti-tuberculosis drug that plays a crucial role in the treatment of both drug-susceptible and multidrug-resistant tuberculosis (MDR-TB). PZA is a prodrug that is converted to its active form, pyrazinoic acid (POA), by a nicotinamidase/pyrazinamidase encoded by the pncA gene, the mutation of which is the major cause of PZA resistance. Although RpsA (ribosomal protein S1, involved in trans-translation) has recently been shown to be a target of POA/PZA, whole-genome sequencing has identified mutations in the panD gene encoding aspartate decarboxylase in PZA-resistant strains lacking pncA and rpsA mutations. To gain more insight into a possible new target of PZA, we isolated 30 POA-resistant mutants lacking mutations in pncA and rpsA from M. tuberculosis in vitro, and whole-genome sequencing of 3 mutants identified various mutations in the panD gene. Additionally, sequencing analysis revealed that the remaining 27 POA-resistant mutants all harbored panD mutations affecting the C-terminus of the PanD protein, with PanD M117I being the most frequent mutation (24/30, 80%). Conditional overexpression of panD from M. tuberculosis, M. smegmatis or E. coli, or of M. tuberculosis mutant PanD M117I, all conferred resistance to POA and PZA in M. tuberculosis. β-alanine and pantothenate, which are downstream products of PanD, were found to antagonize the antituberculosis activity of POA. In addition, the activity of the M. tuberculosis PanD enzyme was inhibited by POA at therapeutically relevant concentrations in a concentration-dependent manner but was not inhibited by the prodrug PZA or the control compound nicotinamide. These findings suggest that PanD represents a new target of PZA/POA. These results have implications for a better understanding of this peculiar persister drug and for the design of new drugs targeting M. tuberculosis persisters for improved treatment.

Evaluation of the diagnostic potential of IP-10 and IL-2 as biomarkers for the diagnosis of active and latent tuberculosis in a BCG-vaccinated population

BACKGROUND

The Mycobacterium tuberculosis (Mtb)-specific T-cell interferon gamma release assays (IGRAs) are useful in detecting Mtb infection but perform poorly at distinguishing active tuberculosis disease (ATB) and latent tuberculosis infection (LTBI). This study is aimed at evaluating additional cytokines as biomarkers besides interferon-gamma (IFN-γ) to improve the identification of ATB and LTBI.

METHODOLOGY/PRINCIPAL FINDINGS

Sixty-six patients with ATB, 73 household contacts (HHC) of ATB patients and 76 healthy controls (HC) were recruited to undergo QuantiFERON TB GOLD in-tube assay (QFT) and the enzyme-linked immunosorbent assay (ELISA) where the release of IFN-γ, IFN-γ inducible protein 10 (IP-10), Interleukin 2 (IL-2) and Tumor Necrosis Factor-α (TNF-α) was determined in the whole blood with or without antigen-stimulation. The positive rates of the QFT, IP-10 and IL-2 tests were 86.4%, 89.4% and 86.4% for the ATB group with no difference between them (p>0.05). However, QFT in combination with IP-10 and IL-2 significantly increased the detection rate to 95.5% in the ATB group (p = 0.03) and the indeterminate rate of all samples decreased from 2.3% (5/215) to 0.4% (1/215). The un-stimulated level of IP-10 was significantly higher in the HHC than the ATB and HC groups. The IP-10 responses were strongly associated with extended Mtb exposure time and the degree of smear-positivity of the index cases. The IL-2/IFN-γ ratio in the antigen-stimulated plasma could discriminate LTBI from ATB with a sensitivity of 77.2% and a specificity of 87.2%.

CONCLUSION

The increased Mtb-specific antigen-stimulated expression of IP-10 and IL-2 may be useful for detecting both ATB and LTBI. Combining the QFT with IP-10 and IL-2 could increase the detection accuracy of active TB over the QFT alone.

Underestimation of the resistance of Mycobacterium tuberculosis to second-line drugs by the new GenoType MTBDRsl test

The GenoType MTBDRsl is a new-generation PCR-based line-probe assay for the detection of extensively drug-resistant tuberculosis (XDR-TB). This study evaluated the performance of MTBDRsl in detecting genotypic resistance to ethambutol, kanamycin, and ofloxacin in Mycobacterium tuberculosis (MTB) strains. The drug resistance of 262 unique clinical MTB isolates from China was analyzed with MTBDRsl, traditional TB drug susceptibility testing (DST), and sequencing. Sensitivity of MTBDRsl was 62.4% (93/149; 95% CI = 54.1 to 70.2) for detection of ethambutol resistance, 57.9% (55/95; 95% CI = 47.3 to 68) for kanamycin resistance, and 81% (111/137; 95% CI = 73.4 to 87.2) for ofloxacin resistance; specificity was 76.8% (86/112; 95% CI = 67.9 to 84.2), 98.8% (164/166; 95% CI = 95.7 to 99.9), and 91.1% (113/124; 95% CI = 84.7 to 95.5), respectively. Sequencing suggested that 36.9% (55/149) of ethambutol-resistant strains had no embB306 mutation and that 26.8% (40/149) had embB497 mutation not covered by MTBDRsl. Furthermore, MTBDRsl indicated ethambutol resistance in 23.2% (26/112) of ethambutol-susceptible strains, of which 92.3% (24/26) were confirmed resistant by sequencing. This study demonstrated that genotypic resistance to ethambutol, kanamycin, and ofloxacin in MTB can be quickly determined with the MTBDRsl. As a rapid and convenient genetic method, this assay could function as a supplement to traditional DST. More relevant genetic markers are needed to improve sensitivity.

Analysis of microRNA expression profiling identifies miR-155 and miR-155* as potential diagnostic markers for active tuberculosis: a preliminary study

To explore biologic behaviors and disease relevance of microRNAs (miRNAs) in the development of active tuberculosis (ATB), we investigated the expression profile of Mycobacterium tuberculosis (MTB) purified protein derivative (PPD)-induced miRNAs to determine the specific miRNAs involved in the pathogenesis of ATB. The expression profile of miRNA under PPD challenge was first measured using microarray analysis in peripheral blood mononuclear cells isolated from ATB patients and healthy controls (HC). The remarkably reactive miRNAs were then validated in a larger cohort by quantitative real-time polymerase chain reaction (qRT-PCR). The receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic value of the determined PPD-responsive miRNAs. The potential targets for those miRNAs were also predicted by computational programs. Fourteen of 866 human miRNAs exhibited at least 1.8-fold difference in the ratio of expression level before and after stimulation with PPD between the ATB and HC groups. The qRT-PCR study validated the findings from microarray-based screening, in which miR-155 exhibited a fold change of 1.4 in the HC group and 3.7 in the ATB group upon PPD stimulation (p < 0.0001); miR-155* exhibited a fold change of 1.9 in the HC and 4.6 in the ATB group (p < 0.005). In ROC plots, the area under the curve was 0.8972 for miR-155 and 0.7945 for miR-155*. The background expression of these 2 microRNAs exhibited no differences between the ATB and HC groups. miR-155 and miR-155* exhibited characteristic expression by TB-specific antigen, suggesting that they can be potential diagnostic markers under the challenge of specific MTB antigens.

Novel biomarkers distinguishing active tuberculosis from latent infection identified by gene expression profile of peripheral blood mononuclear cells

Background

Humans infected with Mycobacterium tuberculosis (MTB) can delete the pathogen or otherwise become latent infection or active disease. However, the factors influencing the pathogen clearance and disease progression from latent infection are poorly understood. This study attempted to use a genome-wide transcriptome approach to identify immune factors associated with MTB infection and novel biomarkers that can distinguish active disease from latent infection.

Methodology/Principal Findings

Using microarray analysis, we comprehensively determined the transcriptional difference in purified protein derivative (PPD) stimulated peripheral blood mononuclear cells (PBMCs) in 12 individuals divided into three groups: TB patients (TB), latent TB infection individuals (LTBI) and healthy controls (HC) (n = 4 per group). A transcriptional profiling of 506 differentially expressed genes could correctly group study individuals into three clusters. Moreover, 55- and 229-transcript signatures for tuberculosis infection (TB&LTBI) and active disease (TB) were identified, respectively. The validation study by quantitative real-time PCR (qPCR) performed in 83 individuals confirmed the expression patterns of 81% of the microarray identified genes. Decision tree analysis indicated that three genes of CXCL10, ATP10A and TLR6 could differentiate TB from LTBI subjects. Additional validation was performed to assess the diagnostic ability of the three biomarkers within 36 subjects, which yielded a sensitivity of 71% and specificity of 89%.

Conclusions/Significance

The transcription profiles of PBMCs induced by PPD identified distinctive gene expression patterns associated with different infectious status and provided new insights into human immune responses to MTB. Furthermore, this study indicated that a combination of CXCL10, ATP10A and TLR6 could be used as novel biomarkers for the discrimination of TB from LTBI.

High-resolution melting facilitates mutation screening of rpsL gene associated with streptomycin resistance in Mycobacterium tuberculosis

Drug resistance remains a serious threat to tuberculosis control worldwide. As one of the important first-line antitubercular agents, resistance to streptomycin (SM) and its derivatives has increased in recent years and has become one of the characteristics of extensively drug-resistant tuberculosis (XDR-TB). A novel rapid assay to screen for rpsL gene mutations associated with SM resistance in Mycobacterium tuberculosis (M. tuberculosis), was developed using high-resolution melting (HRM) analysis. The HRM results of 134 SM-resistant clinical isolates and 20 SM-susceptible clinical isolates of M. tuberculosis for rpsL gene mutations were perfectly matched with those of DNA sequencing. SM resistance was highly associated with rpsL mutations in M. tuberculosis. HRM technique represented an inexpensive, highly sensitive and high-throughput method to facilitate the screening of large numbers of clinical samples for epidemiological studies of drug-resistance of M. tuberculosis, especially in developing countries.

[Evaluation of low-dose amphotericin B and flucytosine in the treatment of cryptococcal meningitis]

OBJECTIVE

To evaluate the efficacy and safety of low-dose amphotericin B (< 0.7 mg x kg(-1) x d(-1)) and flucytosine in patients with non-AIDS-associated cryptococcal meningitis.

METHODS

In non-AIDS patients with cryptococcal meningitis admitted to Huashan Hospital, Fudan University in Shanghai from January 1998 to December 2007, 31 were initially treated with low-dose amphotericin B and flucytosine for more than 1 week. The clinical characteristics, clinical responses, drug-related adverse reactions and outcome of these patients were retrospectively evaluated.

RESULTS

Among the 31 patients enrolled in this study, 8 patients had one or more predisposing factors. Headache, fever, meningeal irritation and vomiting were common clinical symptoms and signs when cryptococcal meningitis was diagnosed. The result of cranial CT scan and/or MRI showed abnormality in 22 cases (78.6%). When the therapy of low-dose amphotericin B and flucytosine ended, the complete response rate was 19.4% (6/31), partial response rate was 54.8% (17/31), and total effective rate was 74.2%. Except for 1 patient lost to follow-up, the 1-year attributable and all-cause mortality among the remaining 30 patients were 0 (0/30) and 10.0% (3/30) respectively. On the other hand, 26 (83.9%) patients had amphotericin B-related adverse reactions, including renal impairment, liver injury, arrhythmia, and anemia, etc. However, most of these reactions were tolerable.

CONCLUSION

Low-dose amphotericin B and flucytosine can be used in non-AIDS-associated cryptococcal meningitis with both acceptable efficacy and safety.

An unusual case of granulomatous lymphadenitis due to Prototheca zopfii var. portoricensis in an immunocompetent man in China

BACKGROUND

Protothecosis is an uncommon human infection caused by Prototheca. Prototheca spp can be considered as saprophytes, and in spite of their frequency in the environment, they are of low virulence and may cause chronic infection with low-grade inflammation in humans. At present, only three species are recognized: Prototheca wickerhamii, Prototheca zopfii and Prototheca stagnora. Of these, the former two have been associated with human disease. This study was an investigation of the clinical and microbiological features of a case of granulomatous lymphadenitis due to P. zopfii var. portoricensis in an immunocompetent man in China.

METHODS

We report the case of a 39-year-old male, who presented with swollen lymph nodes, from which the organism was isolated and identified by the RapidID Yeast Plus test (Remel, Santa Fe, NM, USA) and PCR molecular analysis. The pathogenicity of the isolate was confirmed in a mouse model and antifungal drug susceptibility testing was carried out.

RESULTS

The pathogen was identified as Prototheca zopfii. The DNA sequence of the 18S SSU rDNA regions of the isolate strain were 100% (1205/1205) identical with Prototheca zopfii var. portoricensis. Antifungal susceptibility tests revealed that it was sensitive to amphotericin B, but resistant to 5-flucytosine, fluconazole, ketoconazole, and itraconazole. The patient responded to treatment with intravenous itraconazole and amphotericin B.

CONCLUSIONS

Based on the patient's symptoms and microscopic evaluation, cultures, and molecular analyses of the isolate, granulomatous lymphadenitis due to P. zopfii var. portoricensis was diagnosed. P. zopfii var. portoricensis as a causative agent of human lymphadenitis in an immunocompetent case has not been reported, though a few cases of protothecosis have been reported in China. The real number of protothecosis cases may be greater than that reported in the literature. Thus, clinicians should be vigilant for any unknown cause of granulomatous lymphadenitis and should undertake an intensive histopathology, mycology examination, and even molecular analysis to rule out or confirm a potential Prototheca infection.

[Factors associated with mortality in cryptococcal meningitis]

OBJECTIVE

To investigate factors associated with mortality in non-AIDS patients with cryptococcal meningitis.

METHODS

We retrospectively reviewed 154 cases of non-HIV cryptococcal meningitis in a tertiary care hospital in China, from 1997 through 2007.

RESULTS

The 1-year attributable mortality was 19.6% (28/143), and overall mortality was 28.7% (41/143). Advanced age (> or = 60 years), delay in diagnosis (> 4 months), hematologic malignancy, solid malignancy, altered mental status (coma, seizure, herniation), and CSF drainage or shunting were factors associated with increased death; factors associated with increased survival were amphotericin B based initial therapy and flucytosine containing therapy. In multivariate analysis, age > or = 60 years, the time from symptom onset to diagnosis > 4 months, coma, cerebral herniation, and non-amphotericin B based initial therapy were independently associated with increased overall mortality; factors independently associated with cause-specific mortality were time from symptom onset to diagnosis > 4 months, cerebral herniation and non-amphotericin B based initial therapy.

CONCLUSION

A variety of factors were associated with mortality in non-AIDS cryptococcal meningitis. Amphotericin B based initial treatment was independently correlated to improved 1-year survival.

High-sensitive and rapid detection of Mycobacterium tuberculosis infection by IFN-gamma release assay among HIV-infected individuals in BCG-vaccinated area

BACKGROUND

An accurate test for Mycobacterium tuberculosis infection is urgently needed in immunosuppressed populations. The aim of this study was to investigate the diagnostic power of enzyme-linked immunospot (ELISPOT)-based IFN-gamma release assay in detecting active and latent tuberculosis in HIV-infected population in bacillus Calmette-Guerin (BCG)-vaccinated area. A total of 100 HIV-infected individuals including 32 active tuberculosis patients were recruited. An ELISPOT-based IFN-gamma release assay, T-SPOT.TB, was used to evaluate the M. tuberculosis ESAT-6 and CFP-10 specific IFN-gamma response. Tuberculin skin test (TST) was performed for all recruited subjects.

RESULTS

The subjects were divided into group HIV+ATB (HIV-infected individuals with active tuberculosis, n = 32), group HIV+LTB (HIV-infected individuals with positive results of T-SPOT.TB assay, n = 46) and group HIV only (HIV-infected individuals with negative results of T-SPOT.TB assay and without evidence of tuberculosis infection, n = 22). In group HIV+ATB and HIV+LTB, T-SPOT.TB positive rate in subjects with TST <5 mm were 50% (16/32) and 41.3% (19/46), respectively. Individuals in group HIV+ATB and HIV+LTB with CD4+ T cells <500/microl, T-SPOT.TB showed a higher sensitivity than TST (64.5% vs. 22.6% and 62.2% vs. 29.7%, respectively, both P < 0.0001). In addition, the sensitivity of T-SPOT.TB assay in group HIV+ATB increased to >85% in patients with TB treatment for less than 1 month and CD4+ T cells > or = 200/microl, while for patients treated for more than 3 months and CD4+ T cells <200/microl, the sensitivity was decreased to only 33.3%. Furthermore, the results could be generated by T-SPOT.TB assay within 24 hours, which was more rapid than TST with 48-72 hours.

CONCLUSION

ELISPOT-based IFN-gamma release assay is more sensitive and rapid for the diagnosis of TB infection in Chinese HIV-infected individuals with history of BCG vaccination, and could be an effective tool for guiding preventive treatment with isoniazid in latently infected people and for TB control in China.

Evolution of hepatitis B virus polymerase mutations in a patient with HBeAg-positive chronic hepatitis B virus treated with sequential monotherapy and add-on nucleoside/nucleotide analogues

BACKGROUND

Nucleoside/nucleotide analogues are a fundamental tool for the treatment of chronic hepatitis B virus (HBV). Sequential anti-HBV treatment might lead to the selection of mutations.

OBJECTIVE

This report aimed to analyze the genetic evolution of the reverse-transcriptase (RT) gene of viral quasispecies in a patient with hepatitis B e antigen (HBeAg)-positive chronic HBV who received, sequentially, lamivudine (LAM), adefovir dipivoxil (ADV), and ADV + telbivudine (LDT) combination treatment over a total of 108 weeks.

METHODS

A 20-year-old Chinese man presented to Huashan Hospital, Fudan University, Shanghai, People's Republic of China, with hepatitis B surface antigen-positive and HBeAg-positive chronic HBV and was sequentially treated with LAM 100 mg/d for 18weeks,ADV 10mg/d for 68weeks, and ADV 10mg/d + LDT 600 mg/d combination treatment for 22 weeks. Compliance was monitored every 4 weeks using a pill count. For genotypic analysis, the RT region of the polymerase gene from the serum of this patient was amplified, cloned, and sequenced. Fifty clones with HBV insert were selected for sequencing at weeks 0 (baseline), 18, 22, 60, 70, 86, and 108.

RESULTS

The rtM204V/L LAM-resistance mutation was detected in 4.4% (2/45) of clones prior to LAM treatment. At week 18 during LAM treatment, the rtM204I mutation became predominant, being present in 79.5% (35/44) of clones. The rtM204I mutation was associated with compensatory mutations (rtL180M and rtT184L). A total of 9.1% (4/44) of the clones harbored the rtL180M + rtT184L + rtM204I mutations. Two new mutations, rtL229V and rtV191I, were detected in 75.0% (33/44) and 11.4% (5/44) of clones, respectively. At week 22 during ADV treatment, LAM-resistance mutations (rtL180M, rtT184L, rtM204I, rtV191I, and rtL229V) were not detected. At week 86 during ADV therapy, the rtN236T ADV-resistance mutation was detected in 58.8% (20/34) of clones. A total of 20.6% (7/34) of the clones harbored the rtK212T + rtM250L mutation, and rtA181V was found in 2.9% (1/34) of the clones. At week 108, after the patient had been receiving ADV + LDT combination therapy for 22 weeks, rtS202G and rtI269T had emerged, representing 28.9% (13/45) and 8.9% (4/45), respectively, of the viral population during ADV + LDT combination treatment. We also detected several polymorphic sites,including rtF221Y, rtS223A, rtI224V, rtN238H, rtL267Q, and rtQ271M, during the sequential treatment. After 22 weeks of combination treatment, HBV DNA count was decreased to less than the lower limit of quantitation (<200 copies/mL).

CONCLUSIONS

This report identified HBV mutations that escaped the antiviral pressure of LAM, ADV, and ADV + LDT in this patient and provided insight into the process of mutation selection through genotypic analysis during antiviral treatment. Mutations selected under sequential treatments of LAM, ADV, and ADV + LDT can lead to a series of compensatory mutations, which partially restore the level of viral replication. ADV administered in combination with LDT appeared to be effective in this selected case with clinical or virologic resistance to sequential treatment with LAM and ADV.

Prevalence of basal core promoter and precore mutations in Chinese chronic hepatitis B patients and correlation with serum HBeAG titers

The A1762T and G1764A mutations in the basal core promoter (BCP) region and the G1896A mutation in the precore (PC) region of hepatitis B virus (HBV) genome are found commonly in HBeAg-negative patients. Experiments in vitro suggest that BCP and PC mutation reduce and abolish HBeAg expression, respectively. In the present study, the prevalence of the BCP and PC mutations were determined in 207 patients with HBeAg positive chronic hepatitis B from China and correlated with the titers of serum HBeAg. None of the patients received antiviral therapy. The HBV genotype was determined by direct sequencing of the HBsAg gene. The BCP and PC mutations were detected by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and confirmed by DNA sequencing. The HBeAg titer was measured by the microparticle enzyme immunoassay. Fifty-one of the 207 patients (24.6%) were infected with genotype B and the remainder with genotype C. The BCP mutations were detected in 103 patients (50%) while the PC mutation was present in 43 (20.8%). Thirteen patients (6.3%) harbored both BCP and PC mutations. No significant difference in the titers of HBeAg was found between patients infected with the two HBV genotypes, but the presence of either the BCP or PC mutation was associated with reduced HBeAg titer (P < 0.05). The presence of both the BCP and PC mutations was accompanied by even lower HBeAg titer (P < 0.05). These findings confirm that in patients with HBeAg, the BCP and PC mutations reduced the expression of HBeAg.

[A clinical study of 49 cases of invasive pulmonary aspergillosis]

OBJECTIVE

Studying the proven and probable invasive pulmonary aspergillosis (IPA) cases of some hospitals in Shanghai to provide evidence for the improvement of IPA clinical diagnosis and therapy.

METHODS

Forty-nine IPA cases were retrospectively analyzed for demography data, host factors, underlying conditions, chest CT, microorganism and histopathology examination, as well as therapy and clinical outcome.

RESULTS

Of 49 subjects including 19 (38.8%) proven and 30 (61.2%) probable IPA, 3 patients (6.1%) had no host factors, 25 patients (51.0%) had IPA associated host factors and underlying conditions, while 21 patients (42.9%) had uncertain fundamental diseases. Chest CT evaluation demonstrated that radiological lesions include nodules in 29 patients, patching in 15, mass in 12, consolidation in 10, cavitation in 34, Halo sign in 19, air bronchogram in 18, crescentic sign in 6, bilateral in 33 and multifocal lesions in 38. The yielding rate of fungus culture in sputum was 26.5% (13/49), and in bronchoalveolar lavage fluid was 66.7% (10/15). Eleven of thirty-six patients (30.6%) had positive results of serum galactomannan antigen tests. Nineteen of twenty-one patients (90.5%) were proven as IPA by lung histologic examinations. Aspergillus fumigatus was the most common pathogen 81.0% (17/21). The responding rate to initial anti-fungus therapy was 50% (21/42).

CONCLUSION

Our study suggests that in IPA patients, bilateral, multifocal and nodular lesion could be the most common radiological characteristic, while Halo and crescentic sign occur occasionally. Invasive technologies are more valuable to IPA diagnosis.

Differential fadE28 expression associated with phenotypic virulence of Mycobacterium tuberculosis

Ability to persist in human macrophages is central to the virulence of Mycobacterium tuberculosis and is not invariable among various strains. Differential gene expression that is associated with phenotypic virulence may provide additional information of virulent genes involved in the pathogenesis of M. tuberculosis, which is not fully elucidated. Three hypervirulent strains of M. tuberculosis isolated from patients suffering with tuberculous meningitis were shown to grow more rapidly inside human macrophages in a previous study. In the current investigation, expression of 7 mycobacterial genes (fadE28, mce1A, mymA, acr, sigA, sugC, and Rv3723) of these strains during ex vivo macrophage challenge and in vitro acid shock was quantified by real-time PCR. Using rrs gene as a normalisation gene, fadE28 gene exhibited differential gene expression that is associated with phenotypic virulence, whereas the other 6 genes showed indistinguishable expression patterns. Up-regulation of fadE28 gene in the hypervirulent strains may account for virulence by increasing the efficiency of beta-oxidation, which is important for the persistence in macrophages as M. tuberculosis uses fatty acids preferably inside phagosome of macrophages. The fadE28 gene, together with its adjacent genes may also be critical in the process of lipid modification that could facilitate parasitism in human macrophages.

Fever of unknown origin: revisit of 142 cases in a tertiary Chinese hospital

To investigate the causes of fever of unknown origin (FUO), we analyzed the clinical data on 142 patients with FUO admitted to our department from January 2002 to December 2003. After various examinations and specific treatment, a definitive diagnosis was reached in 122 cases. Of them, 51 cases (35.9%) were caused by infections, 46 (32.4%) were due to autoimmune diseases, 18 (12.7%) were due to tumors, 7 (4.9%) were due to other diseases, and in 20 (14.1%) the cause was still unknown after hospitalization. In conclusion, infection is the main cause of FUO. Autoimmune diseases and malignant tumors are both significant causes. Most patients with an FUO were ultimately diagnosed with various examinations and careful analysis.

Kinematic Design of a Radius-Variable Gripper with 1-D.O.F. Used in High-Voltage Hot-Line Cleaning Robot

This paper presents the design of a novel radius-variable-gripper (RVG) for use as end-effector of high-voltage hot-line cleaning robot (HVCR). A eight-bar linkage mechanism is proposed to obtain the aim of 1-dof acutuation. According to the shape of insulators, the dimension design and kinematic analysis of RVG have been carried out. The optimization is performed to locate the joint points of arm segments, on which the brushes are mounted, approximately on the position circles in the whole opening-and-closing process of RVG. The prototype has been given finally, and it is showed that RVG is feasible to this special application.

Molecular characterization of clinical isolates of Mycobacterium tuberculosis and their association with phenotypic virulence in human macrophages

Among 125 clinical isolates of Mycobacterium tuberculosis collected in Hong Kong and Shanghai, China, between 2002 and 2004, IS6110 typing revealed that 71 strains (57%) belonged to the Beijing family. The intracellular growth of the strains in human peripheral blood monocyte-derived macrophages was measured ex vivo on days 0, 3, 6, and 10. Among all tested strains, three hypervirulent strains showed significant increases in intracellular growth after 10 days of incubation. With an initial bacterial load of 10(4) CFU, most of the clinical isolates and H37Ra (an avirulent strain) exhibited no intracellular survival on day 10, while the three hypervirulent strains together with H37Rv (a virulent strain) showed on average a two- to fourfold rise in CFU count. These three hypervirulent strains belonging to a non-Beijing family were isolated from patients suffering from tuberculosis meningitis. Cytokines secreted by gamma interferon-activated macrophages were measured daily after challenge with selected strains of M. tuberculosis. The levels of tumor necrosis factor alpha were elevated after 24 h of infection among all strains, but the levels were significantly lower among the three hypervirulent strains, whereas interleukin 10 (IL-10) and IL-12 were not detected. Results were concordant with the differential expression of the corresponding cytokine genes in activated macrophages, as monitored by real-time PCR. Our findings highlighted that these three hypervirulent strains may possess an innate mechanism for escaping host immunity, which accounts for their characteristic virulence in patients presenting with a more severe form of disease.

Tumor Suppressor CYLD Regulates Acute Lung Injury in Lethal Streptococcus pneumoniae Infections

Streptococcus pneumoniae (S. pneumoniae) causes high early mortality in pneumococcal pneumonia, which is characterized by acute lung injury (ALI). The molecular mechanisms underlying ALI and the high early mortality remain unknown. Despite recent studies that identify deubiquitinating enzyme cylindromatosis (CYLD) as a key regulator for T cell development, tumor cell proliferation, and NF-kappaB transcription factor signaling, its role in regulating bacteria-induced lethality, however, is unknown. Here, we showed that CYLD deficiency protected mice from S. pneumoniae pneumolysin (PLY)-induced ALI and lethality. CYLD was highly induced by PLY, and it inhibited MKK3-p38 kinase-dependent expression of plasminogen activator inhibitor-1 (PAI-1) in lung, thereby potentiating ALI and mortality. Thus, CYLD is detrimental for host survival, thereby indicating a mechanism underlying the high early mortality of pneumococcal pneumonia.

Opposing roles of PAK2 and PAK4 in synergistic induction of MUC5AC mucin by bacterium NTHi and EGF

Mucin, a major component of mucus, plays a critical role in host mucosal defense response by participating in mucociliary clearance. However, if overproduced, overproduced mucus leads to airway mucus obstruction and conductive hearing loss. Despite extensive studies that focus on investigating how MUC5AC mucin is regulated by one inducer at a time, how MUC5AC is synergistically regulated by multiple factors remains unknown. Here we provide direct evidence for the first time that bacterial pathogen NTHi and human growth factor EGF synergize with each other to potently up-regulate MUC5AC mucin transcription. Moreover, activation of both p38 and ERK is required for synergistic induction of MUC5AC by NTHi and EGF. Finally, PAK2 and PAK4 are differentially involved in this synergistic induction of MUC5AC by acting upstream of p38 and ERK. Our studies bring novel insights into our understanding of synergistic regulation of MUC5AC mucin by both pathological and physiological inducers.

[The rate of hepatitis B virus resistance to adefovir dipivoxil (ADV) and the evolution of hepatitis B virus in lamivudine-resistant chronic hepatitis B patients with ADV monotherapy]

OBJECTIVE

To study the resistant rate of hepatitis B virus (HBV) to ADV and the dynamic evolution of HBV in lamivudine (Lam)-resistant chronic hepatitis B (CHB) patients.

METHODS

Twenty-three Lam-resistant CHB patients were assigned to a 10mg/d ADV monotherapy for 68-116 weeks. The baseline and different time point blood samples after ADV monotherapy were analyzed for ADV-resistant mutations using direct sequencing of PCR products; the evolution of HBV mutations was examined by clonal analysis of serial samples from one patient infected with ADV-associated resistant HBV strains.

RESULTS

The cumulative incidence of genotypic ADV resistance at weeks 48 and 96 was 4.3% and 10.5% respectively respectively. The evolution analysis of HBV mutant strains in an ADV-resistant CHB patient showed that the proportion of YMDD mutants gradually decreased with rtA181S mutants increasing over time after ADV monotherapy, and that rtA181S+N236T mutants became the predominant strains during prolonged ADV monotherapy. The addition of Lam to the ongoing ADV treatment had poorer antiviral response in the patient with rtA181S or rtA181S+N236T mutant infection; one clone with multi-drug resistant mutations was selected during Lam and ADV combination therapy.

CONCLUSION

Increased risk of adefovir resistance and selection of multi-drug resistant mutations are associated with long-term ADV monotherapy in patients with Lam-resistant chronic hepatitis B.

[Phenotypes and functions of dendritic cells derived from peripheral blood monocytes of chronic hepatitis B patients with different HBV DNA loads]

OBJECTIVE

To investigate the phenotypes and functions of peripheral blood monocyte derived dendritic cells (DC) of chronic hepatitis B (CHB) patients with different HBV DNA loads.

METHODS

Twenty-eight CHB patients were included in this study. All patients were treated with nucleoside analogues (lamivudine or LdT or adefovir) for 24 weeks. Peripheral blood HBV DNA loads and liver biopsies were assessed before and after the treatment. The patients were divided into two groups according to their peripheral blood HBV DNA loads: a high-load group with HBV DNA loads higher than 10(5) copies/ml, and a low-load group with HBV DNA loads lower than 10(3) copies/ml. Ten healthy people were included as controls. Peripheral blood DC of each subject was enriched. The phenotypes of DC were subjected to flow cytometric analysis. The lymphocyte allo-stimulatory capacity of DC was evaluated through MTT assay. IL-10 and IL-12 production were quantified by ELISA.

RESULTS

DC proliferated successfully when stimulated by cytokines in vitro; however, DC of the CHB patients proliferated much slower than those of the healthy controls. The expression of DC surface molecules such as HLA-DR, CD86, CD80 and CD83 had a positive rate of over 80% in the normal population. However in our CHB patients they showed lower than normal expressions, especially the HLA-DR, CD86, CD80 and CD83, but the differences were not significant between the two groups with different virus loads. The stimulatory capacity of the DC in mixed lymphocyte reaction showed no difference between the two groups of patients, but both were lower than that of the healthy controls. The production of IL-12 and IL-10 also decreased significantly in the patients.

CONCLUSIONS

Peripheral DC of CHB patients have some defects in their phenotypes and their stimulatory capacity. The changes in phenotypes and down-regulation of the functions are not relevant to peripheral HBV DNA loads of the patients.

[Hepatic safety of itraconazole intravenous solution in treatment of invasive fungal infection]

OBJECTIVE

To investigate the hepatic safety of itraconazole intravenous solution in the treatment of invasive fungal infection.

METHODS

Forty-nine patients with invasive fungal infection, such as pneumonia, meningitis, endocarditis, and blood stream infection, caused by Aspergillus spp. Cryptococcus neoformans, Candida spp. Penicillium marneffei, and Prototheca wickerhamii, 50 of which had underlying diseases, including hepatic diseases, such as hepatitis, cirrhosis, fatty liver etc. were treated with intravenous itraconazole for 12.6 days (2 - 42 days). Liver function test was conducted before and after the treatment. The relationship between liver adverse reaction and itraconazole treatment was evaluated.

RESULTS

Liver function test was abnormal in 20 patients. The patients with liver enzyme abnormalities before itraconazole treatment were easier to suffer from hepatic damage during itraconazole treatment (chi(2) = 11.54, P = 0.001). However, only in 2 patients with mild liver function test abnormality the liver adverse reaction could be associated with itraconazole treatment.

CONCLUSION

Itraconazole treatment for invasive fungal infection is rather safe, even in the patients with underlying hepatic diseases. Liver function test is recommended for all patients suggestive of liver dysfunction and protective therapy for liver is needed.

Antibody response to four secretory proteins from Mycobacterium tuberculosis and their complex antigen in TB patients

OBJECTIVE

To evaluate antibody responses to a panel of four protein antigens secreted from Mycobacterium tuberculosis, CFP-21, ESAT-6, MPT-63 and MPT-64, and their complex antigen.

DESIGN

Seventy-eight samples of serum and cerebral spinal fluid were tested by ELISA.

RESULTS

Serum IgM antibody positive rates of protein antigens CFP-21, ESAT-6, MPT-63 and MPT-64 and their multi-antigen complex were respectively 34.6%, 60.3%, 52.6%, 78.2% and 96.2%; IgG antibody positive rates were respectively 46.2%, 64.1%, 93.6%, 57.7% and 84.6%. The specificity of the antibodies to the four proteins secreted from M. tuberculosis and its mixture antigen was 100%; sensitivity to the multi-antigen complex was higher than for the four single antigens. Among the IgM positive rates, the differences between the multi-antigen complex and CFP-21, ESAT-6, MPT-63 and MPT-64 were significant (P < 0.01); among the IgG positive rates, the differences between the multi-antigen complex and CFP-21, ESAT-6 and MPT-64 were significant (P < 0.01). Although the IgG positive rate for MPT-63 was higher than for the multi-antigen complex, the difference was not significantly different (P > 0.05).

CONCLUSION

These findings indicate that the multi-antigen complex composed of CFP-21, ESAT-6, MPT-63 and MPT-64 may be useful in the diagnosis of TB.

[A new multiplex allele-specific polymerase chain reaction assay for detection of rifampin-resistant Mycobacterium tuberculosis]

OBJECTIVE

To develop a new multiplex allele-specific polymerase chain reaction (MAS-PCR) assay to detect the main mutations in the rifampin resistance dependent region, which has been reported to account for the majority of clinic Mycobacterium tuberculosis resistant to rifampin.

METHODS

Based on the sequence of rpoB gene, three specific primers were designed for the MAS-PCR to detect the most common mutations in codons 531, 526, 516 of rpoB gene.

RESULTS

The purified DNA preparations of 91 clinical strains of Mycobacterium tuberculosis were used to optimize the PCR. The mutations in codon 531, 526, 516 were detected by the MAS-PCR. Compared with the results of direct sequencing of rpoB gene, no mutation was detected in the sensitive strains. For rifampin-resistant strains, the total sensitivity was 81.5% (66/81).

CONCLUSIONS

MAS-PCR is a new molecular method with a high sensitivity and specificity, which can be used to detect the 3 main mutations of rpoB gene rapidly and economically. It can be used in clinical laboratories to detect the rifampin-resistant strains of Mycobacterium tuberculosis.

Cryptococcal antigen test revisited: significance for cryptococcal meningitis therapy monitoring in a tertiary chinese hospital

For a total of 29 non-human immunodeficiency virus 1 cryptococcal meningitis cases, titer changes in the latex agglutination test before and after therapy were reviewed along with clinical manifestations, laboratory findings, and therapy regimens. The cryptococcal antigen titer decreased for every case after therapy and was correlated to fungal clearance as defined by fungus smear and/or culture. However, cryptococcal antigen can remain at low titers for long periods of time after therapy, even when fungus smears and/or cultures become negative.

[Comparison of four methods in the detection of isoniazid resistance in clinical isolates of Mycobacterium tuberculosis]

OBJECTIVE

To evaluate the use of phage amplified biologically (PhaB) assay, Bactec-960 system, minimum inhibitory concentration (MIC) method and gene chip in drug susceptibility testing of isoniazid (INH) in clinical isolates of Mycobacterium tuberculosis (MTB).

METHODS

INH resistance of 167 clinical isolates of MTB was detected by PhaB assay, Bactec-960 system, MIC and gene-chip methods respectively, and the results of these four methods were compared.

RESULTS

111 INH resistant isolates and 56 INH sensitive isolates were detected by Bactec-960 system. If the result of Bactec-960 system was set as the golden standard, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PhaB assay were 96.4%, 96.4%, 93.1%, 98.2%, and 96.4% respectively; the sensitivity, specificity, PPV, NPV, and accuracy were 92.9%, 99.1%, 98.1%, 96.5%, and 97.0% for the MIC method, and they were 83.9%, 96.4%, 92.2%, 92.2%, and 92.2% respectively for the gene-chip method. If the result of the MIC method was set as the golden standard, the sensitivity, specificity, PPV, NPV, and accuracy of PhaB assay were 100%, 95.6%, 91.4%, 100%, and 97.0% respectively. The sensitivity, specificity, PPV, NPV, and accuracy were 98.1%, 96.5%, 92.9%, 99.1%, and 97.0% for the Bactec-960 system, and they were 88.7%, 96.5%, 92.2%, 94.8%, and 94.0% respectively for the gene-chip method.

CONCLUSIONS

The PhaB assay is highly sensitive and specific, and its result is highly consistent with those of the Bactec-960 system and the MIC method. It is easy to use and took only three days in the detection of drug susceptibility of INH in clinical isolates of MTB. The results indicate that this low-cost assay can be used in rapid screening for INH resistance in MTB isolates. The MIC method proves to be as efficient as the Bactec-960 system, but whether it can be used as the standard method still needs further investigation. The sensitivity of the gene-chip method is lower as compared to the other methods, and therefore can only be used as an ancillary test.