Spatial distribution and risk factors of Schistosoma haematobium and hookworm infections among schoolchildren in Kwale, Kenya.

BACKGROUND: Large-scale schistosomiasis control programs are implemented in regions with diverse social and economic environments. A key epidemiological feature of schistosomiasis is its small-scale heterogeneity. Locally profiling disease dynamics including risk factors associated with its transmission is essential for designing appropriate control programs. To determine spatial distribution of schistosomiasis and its drivers, we examined schoolchildren in Kwale, Kenya. METHODOLOGY/PRINCIPAL FINDINGS: We conducted a cross-sectional study of 368 schoolchildren from six primary schools. Soil-transmitted helminths and Schistosoma mansoni eggs in stool were evaluated by the Kato-Katz method. We measured the intensity of Schistosoma haematobium infection by urine filtration. The geometrical mean intensity of S. haematobium was 3.1 eggs/10 ml urine (school range, 1.4-9.2). The hookworm geometric mean intensity was 3.2 eggs/g feces (school range, 0-17.4). Heterogeneity in the intensity of S. haematobium and hookworm infections was evident in the study area. To identify factors associated with the intensity of helminth infections, we utilized negative binomial generalized linear mixed models. The intensity of S. haematobium infection was associated with religion and socioeconomic status (SES), while that of hookworm infection was related to SES, sex, distance to river and history of anthelmintic treatment. CONCLUSIONS/SIGNIFICANCE: Both S. haematobium and hookworm infections showed micro-geographical heterogeneities in this Kwale community. To confirm and explain our observation of high S. haematobium risk among Muslims, further extensive investigations are necessary. The observed small scale clustering of the S. haematobium and hookworm infections might imply less uniform strategies even at finer scale for efficient utilization of limited resources.

A novel approach to automated genotyping of Mycobacterium tuberculosis using a panel of 15 MIRU VNTRs.

In this study, we present a new approach to variable number tandem repeats (VNTR) analysis using the QIAxcel capillary electrophoresis system and a software-integrated peak calling function. Allelic ladders representing 15 mycobacterial interspersed repetitive units (MIRU)-VNTR loci were used to define peak calling tables thereby enabling high precision Mycobacterium tuberculosis strain identification.

Antigen 85A and mycobacterial DNA-binding protein 1 are targets of immunoglobulin G in individuals with past tuberculosis.

Development of accurate methods for predicting progression of tuberculosis (TB) from the latent state is recognized as vitally important in controlling TB, because a majority of cases develop from latent infections. Past TB that has never been treated has a higher risk of progressing than does latent Mycobacterium tuberculosis infection in patients who have previously received treatment. Antibody responses against 23 kinds of M. tuberculosis proteins in individuals with past TB who had not been medicated were evaluated. These individuals had significantly higher concentrations of antibodies against Antigen 85A and mycobacterial DNA-binding protein 1 (MDP1) than did those with active TB and uninfected controls. In addition, immunohistochemistry revealed colocalization of tubercle bacilli, antigen 85 and MDP1 inside tuberculous granuloma lesions in an asymptomatic subject, showing that M. tuberculosis in lesions expresses both antigen 85 and MDP1. Our study suggests the potential usefulness of measuring antibody responses to antigen 85A and MDP1 for assessing the risk of TB progression.

Loss of anti-mycobacterial efficacy in mice over time following vaccination with Mycobacterium bovis bacillus Calmette-Guérin.

Mycobacterium bovis bacillus Calmette-Guérin (BCG) is the most often used vaccine worldwide and sole vaccine against tuberculosis. BCG is protective against severe form of childhood tuberculosis but less or not protective to adult pulmonary tuberculosis. Therefore, improved vaccination strategies and development of new tuberculosis vaccines are urgent demands. For those purposes, appropriate animal models that reflect human are critically useful. However, in animal models, BCG vaccination protects well against subsequent challenge of Mycobacterium tuberculosis. In this study we evaluated the duration of protective efficacy of the BCG vaccination in mice over time and found that efficacy was diminished 40 weeks after vaccination. The aged mice older than 45 weeks are protected sufficiently after the vaccination with BCG, suggesting that loss of its efficacy is not dependent on the age of mice but rather depends on the period from vaccination. The loss of protection occurred in TH1 polarized STAT6 deficient mice despite the maintenance of interferon (IFN)-gamma production activity of lymph node cells and splenic CD4(+) T cells against M. tuberculosis antigens. Our data suggest that the duration from vaccination may explain the variation in BCG efficacy against adult pulmonary tuberculosis.

Tuberculosis infection among homeless persons and caregivers in a high-tuberculosis-prevalence area in Japan: a cross-sectional study.

BACKGROUND: Tuberculosis (TB) is a major public health problem. The Airin district of Osaka City has a large population of homeless persons and caregivers and is estimated to be the largest TB-endemic area in the intermediate-prevalence country, Japan. However, there have been few studies of homeless persons and caregivers. The objective of this study is to detect active TB and to assess the prevalence and risk factors for latent TB infection among homeless persons and caregivers. METHODS: We conducted a cross-sectional study for screening TB infection (active and latent TB infections) using questionnaire, chest X-ray (CXR), newly available assay for latent TB infection (QuantiFERON-TB Gold In-Tube; QFT) and clinical evaluation by physicians at the Osaka Socio-Medical Center Hospital between July 2007 and March 2008. Homeless persons and caregivers, aged 30-74 years old, who had not received CXR examination within one year, were recruited. As for risk factors of latent TB infection, the odds ratios (OR) and 95% confidence intervals (95% CI) for QFT-positivity were calculated using logistic regression model. RESULTS: Complete responses were available from 436 individuals (263 homeless persons and 173 caregivers). Four active TB cases (1.5%) among homeless persons were found, while there were no cases among caregivers. Out of these four, three had positive QFT results. One hundred and thirty-three (50.6%) homeless persons and 42 (24.3%) caregivers had positive QFT results. In multivariate analysis, QFT-positivity was independently associated with a long time spent in the Airin district: ≥10 years versus <10 years for homeless (OR = 2.53; 95% CI, 1.39-4.61) and for caregivers (OR = 2.32; 95% CI, 1.05-5.13), and the past exposure to TB patients for caregivers (OR = 3.21; 95% CI, 1.30-7.91) but not for homeless persons (OR = 1.51; 95% CI, 0.71-3.21). CONCLUSIONS: Although no active TB was found for caregivers, one-quarter of them had latent TB infection. In addition to homeless persons, caregivers need examinations for latent TB infection as well as active TB and careful follow-up, especially when they have spent a long time in a TB-endemic area and/or have been exposed to TB patients.

Mycobacteria exploit host hyaluronan for efficient extracellular replication.

In spite of the importance of hyaluronan in host protection against infectious organisms in the alveolar spaces, its role in mycobacterial infection is unknown. In a previous study, we found that mycobacteria interact with hyaluronan on lung epithelial cells. Here, we have analyzed the role of hyaluronan after mycobacterial infection was established and found that pathogenic mycobacteria can grow by utilizing hyaluronan as a carbon source. Both mouse and human possess 3 kinds of hyaluronan synthases (HAS), designated HAS1, HAS2, and HAS3. Utilizing individual HAS-transfected cells, we show that HAS1 and HAS3 but not HAS2 support growth of mycobacteria. We found that the major hyaluronan synthase expressed in the lung is HAS1, and that its expression was increased after infection with Mycobacterium tuberculosis. Histochemical analysis demonstrated that hyaluronan profoundly accumulated in the granulomatous legion of the lungs in M. tuberculosis-infected mice and rhesus monkeys that died from tuberculosis. We detected hyaluronidase activity in the lysate of mycobacteria and showed that it was critical for hyaluronan-dependent extracellular growth. Finally, we showed that L-Ascorbic acid 6-hexadecanoate, a hyaluronidase inhibitor, suppressed growth of mycobacteria in vivo. Taken together, our data show that pathogenic mycobacteria exploit an intrinsic host-protective molecule, hyaluronan, to grow in the respiratory tract and demonstrate the potential usefulness of hyaluronidase inhibitors against mycobacterial diseases.

Virulence of Mycobacterium avium complex strains isolated from immunocompetent patients.

Mycobacterium avium complex (MAC) disease has been increasing worldwide not only in immunocompromised but also in immunocompetent humans. However, the relationship between mycobacterial strain virulence and disease progression in immunocompetent humans is unclear. In this study, we isolated 6 strains from patients with pulmonary MAC disease. To explore the virulence, we examined the growth in human THP-1 macrophages and pathogenicity in C57BL/6 mice. We found that one strain, designated 198, which was isolated from a patient showing the most progressive disease, persisted in THP-1 cells. In addition, strain 198 grew to a high bacterial load with strong inflammation in mouse lungs and spleens 16 weeks after infection. To our knowledge, strain 198 is the first isolated MAC strain that exhibits hypervirulence consistently for the human patient, human macrophages in vitro, and even for immunocompetent mice. Other strains showed limited survival and weak virulence both in macrophages and in mice, uncorrelated to disease progression in human patients. We demonstrated that there is a hypervirulent clinical MAC strain whose experimental virulence corresponds to the serious disease progression in the patients. The existence of such strain suggests the involvement of bacterial virulence in the pathogenesis of pulmonary MAC disease in immunocompetent status.

Efficacy and safety of sitagliptin monotherapy in Japanese patients with type 2 diabetes.

Efficacy and tolerability of sitagliptin, a dipeptidyl peptidase-4 inhibitor, were assessed in Japanese patients with type 2 diabetes. In a multicenter, double-blind, randomized, placebo-controlled trial in Japan, 151 patients with inadequate glycemic control [HbA(1c) > or =6.5% to <10%, fasting plasma glucose (FPG) > or =126 to < or =240 mg/dL] were randomized to once-daily sitagliptin 100mg or placebo for 12 weeks. After 12 weeks, the least squares (LS) mean change from baseline HbA(1c) was -0.65% (95% CI: -0.80, -0.50) with sitagliptin versus 0.41% (0.26, 0.56) with placebo [between-group difference=-1.05% (-1.27, -0.84); p<0.001]. LS mean change from baseline FPG was -22.5mg/dL (95% CI: -28.0, -17.0) with sitagliptin versus 9.4 mg/dL (3.9, 14.9) with placebo [between-group difference=-31.9 mg/dL (95% CI: -39.7,-24.1); p<0.001]. More patients achieved HbA(1c) <7% or <6.5% with sitagliptin than with placebo (p<0.001). Following a meal tolerance test, 2-h postprandial glucose was significantly reduced with sitagliptin relative to placebo. Clinical and laboratory adverse experiences were similar between treatments, with no reported hypoglycemia adverse events with sitagliptin. Body weight was unchanged relative to baseline in the sitagliptin group (-0.1 kg), but significantly (p<0.01) different relative to the placebo group (-0.7 kg). In this study, once-daily sitagliptin 100mg for 12 weeks improved fasting and postprandial glycemic control and was generally well tolerated in Japanese patients with type 2 diabetes.

Antihypertensive efficacy and safety of fixed-dose combination therapy with losartan plus hydrochlorothiazide in Japanese patients with essential hypertension.

A randomized, double-blind, placebo-controlled, parallel-group multicenter study was conducted to evaluate the antihypertensive efficacy and safety of 8-week treatment with one of three fixed-dose combinations-losartan 50 mg plus hydrochlorothiazide 12.5 mg, losartan 50 mg plus hydrochlorothiazide 6.25 mg, or losartan 25 mg plus hydrochlorothiazide 6.25 mg-in comparison with those of hydrochlorothiazide 12.5 mg alone, losartan 50 mg alone, or placebo in Japanese patients with essential hypertension. Significant reductions in sitting diastolic blood pressure (DBP) and systolic blood pressure (SBP) were seen in all three combination groups compared with the placebo group (each p<0.001). The greatest reductions in DBP and SBP were observed in the losartan 50 mg plus hydrochlorothiazide 12.5 mg group (12.7 and 18.0 mmHg, respectively). The reductions in the losartan 50 mg plus hydrochlorothiazide 12.5 mg group were significantly greater (each p<0.001) than those in the placebo group and each of the monotherapy groups. There were no significant differences in the incidences of clinical and laboratory drug-related adverse events between any of the combination groups and the placebo group. All combination groups showed improved hypokalemia and hyperuricemia compared to the hydrochlorothiazide 12.5 mg group. These results demonstrated that once-daily, fixed-dose combination therapy with losartan 50 mg plus hydrochlorothiazide 12.5 mg is well tolerated and more efficacious in lowering DBP and SBP than monotherapy in Japanese hypertensive patients.

[Significance of tuberculosis screening of outpatients in areas with high prevalence of tuberculosis].

OBJECTIVE: The Osaka Socio-Medical Center Hospital is a medical care facility located in the Airin area of Osaka city where the prevalence of tuberculosis is high, and treats day laborers and homeless people mainly, either free of charge or with a small fee. To investigate whether this hospital can play a role to reduce the prevalence of tuberculosis in this area, we investigated the case rate of active tuberculosis in outpatients of the hospital. SUBJECTS AND METHODS: Of 1673 patients who first visited the Orthopaedic Outpatient Clinic between March 31, 2005 and June 15, 2006, 538 patients consented to undergo screening and underwent chest X-ray examination (screening group). We also analyzed chest X-ray examination in 2000 patients examined at the Department of Internal Medicine during the same period (control group). RESULTS: Of the 538 patients in the screening group (523 males and 15 females), 13 male patients (2.4%) requiring treatment were detected. Of the 2000 patients in the control group, 85 patients (84 males and 1 female) (4.3%) requiring treatment were detected. CONCLUSION: The tuberculosis case rate (2.4%) in the screening group was similar to that of tuberculosis screenings (1.1-1.8%) in the Airin area in 2004. The case rate in the control group was two times higher. Since the prevalence is very high in patients of this hospital, the hospital should play a significant role in the health care of tuberculosis patients in this community by reinforcing the screening system and enriching the outpatient clinic system.

DNA augments antigenicity of mycobacterial DNA-binding protein 1 and confers protection against Mycobacterium tuberculosis infection in mice.

Mycobacterium consists up to 7% of mycobacterial DNA-binding protein 1 (MDP1) in total cellular proteins. Host immune responses to MDP1 were studied in mice to explore the antigenic properties of this protein. Anti-MDP1 IgG was produced after infection with either bacillus Calmette-Guérin or Mycobacterium tuberculosis in C3H/HeJ mice. However, the level of Ab was remarkably low when purified MDP1 was injected. MDP1 is considered to be associated with DNA in nucleoid, which contains immunostimulatory CpG motif. Therefore, we examined coadministration of MDP1 and DNA derived from M. tuberculosis. Consequently, this procedure significantly enhanced the production of MDP1-specific IgG. Five nanograms of DNA was enough to enhance MDP1-specific IgG production in the administration of 5 microg of MDP1 into mice. Strong immune stimulation by such a small amount of DNA is noteworthy, because >1,000- to 100,000-fold doses of CpG DNAs are used for immune activation. A synthetic peptide-based study showed that B cell epitopes were different between mice administered MDP1 alone and those given a mixture of MDP1 and DNA, suggesting that DNA alters the three-dimensional structure of MDP1. Coadministration of DNA also enhanced MDP1-specific IFN-gamma production and reduced the bacterial burden of a following challenge of M. tuberculosis, showing that MDP1 is a novel vaccine target. Finally, we found that MDP1 remarkably enhanced TLR9-dependent immune stimulation by unmethylated CpG oligo DNA in vitro. To our knowledge, MDP1 is the first protein discovered that remarkably augments the CpG-mediated immune response and is a potential adjuvant for CpG DNA-based immune therapies.

Extracellular mycobacterial DNA-binding protein 1 participates in mycobacterium-lung epithelial cell interaction through hyaluronic acid.

Mycobacterium tuberculosis infects not only host macrophages but also nonprofessional phagocytes, such as alveolar epithelial cells. Glycosaminoglycans (GAGs) are considered as the component of mycobacterial adherence to epithelial cells. Here we show that extracellularly occurring mycobacterial DNA-binding protein 1 (MDP1) promotes mycobacterial infection to A549 human lung epithelial cells through hyaluronic acid (HA). Both surface plasmon resonance analysis and enzyme-linked immunosorbent assay revealed that MDP1 bound to HA, heparin, and chondroitin sulfate. Utilizing synthetic peptides, we next defined heparin-binding site of 20 amino acids from 31 to 50 of MDP1, which is responsible for the specific DNA-binding site of MDP1. MDP1 bound to A549 cells, and exogenous DNA and HA interfered with the interaction. The binding was also abolished by treatment of A549 cells with hyaluronidase, suggesting that HA participates in the MDP1-A549 cell interaction. Adherence of bacillus Calmette-Guérin (BCG) and M. tuberculosis to A549 cells was inhibited by addition of HA, DNA, and anti-MDP1 antibody, showing that MDP1 participates in the interaction between mycobacteria-alveolar epithelial cells. Simultaneous treatment of intratracheal BCG-infected mice with HA reduced the growth of BCG in vivo. Taken together, theses results suggest that HA participates in Mycobacterium-lung epithelium interaction and has potential for therapeutic and prophylactic interventions in mycobacterial infection.