Tuberculosis and HIV: a partnership against the most vulnerable

Ethnic disparities in tuberculosis incidence and related factors among indigenous and other communities in ethnically diverse Suriname

Background

In Suriname, a country home to many ethnic groups, a high incidence of tuberculosis (TB) has been found among Indigenous Trio Amerindians. However, whether wider ethnic disparities in TB incidence and its associated risk factors (e.g., diabetes mellitus and HIV) exist in Suriname, is not known. We sought to investigate disparities in TB incidence and its risk factors on ethnicity in Suriname, as this could give way to targeted TB intervention programs.

Methods

Anonymized patient data from 2011 to 2015 was extracted from the National TB Registry and analyzed. Differences in the five-year incidence rates of TB for the six largest ethnic groups-Creole, Hindustani, Indigenous, Javanese, Maroon, and Mixed-were assessed using a chi-square goodness-of-fit test, and TB patient differences regarding ethnicity were evaluated for selected factors using a multinomial logistic regression with Creole patients as reference.

Results

662 Patients were eligible for analyses with the following ethnic makeup: Creole (36.4%), Hindustani (15.6%), Indigenous (8.6%), Javanese (10.6%), Maroon (15.1%), and Mixed ethnicity (13.7%). Differences in five-year incidence rates for TB were significant, χ ²(5, N = 662) = 244.42, p < .001, and the highest TB rates were found for Indigenous (280 per 100,000) and Creole people (271 per 100,000). HIV coinfection was a TB risk factor for Creoles (38.2% of these patients were HIV positive). Several variables (i.e., those for drug use) had high levels of incomplete or missing data.

Conclusions

Our study has demonstrated that ethnic disparities in tuberculosis incidence exist in Suriname and that they are associated with specific, known risk factors such as HIV (especially for Creole people). For Indigenous people, risk factors may include diminished access to health care facilities and low socioeconomic status. However, direct data on these factors was unavailable. These findings call for targeted national intervention programs-with special attention given to the vulnerabilities of susceptible ethnic groups-and improved data collection.

Strategies towards the synthesis of anti-tuberculosis drugs

In this report, we reviewed the strategies towards the synthesis of anti-tuberculosis drugs. They include semisynthetic approaches, resolution based strategies, microbial transformations, solid phase synthesis, and asymmetric synthesis.

Tuberculosis and human immunodeficiency virus coinfection: Epidemiological situation in the department of Meta, 2010- 2015

Introduction. One third of the increase in tuberculosis cases is attributed to the spread of HIV. Objective. To describe the Tb/HIV coinfection in the department of Meta from 2010 to 2015. Materials and methods. We conducted an observational, descriptive and retrospective study. After selecting 219 cases for analysis, two new databases were constructed and analyzed in three phases: Identification of sociodemographic and clinical characteristics, indicators by municipality (prevalence and therapeutic success) and stratification in epidemiological scenarios according to the prevalence (burden) of the illness. Results. Sixty percent of the municipalities corresponded to scenario 2. People with Tb/HIV coinfection who had not been treated previously, had 2.39 times more probability of having therapeutic success compared to those previously treated, this association being statistically significant (RP=2,39; 95% CI 1,3-9,6; p=0,01). Conclusion. Stratification by epidemiological scenarios is useful for planning prevention and control activities.

Tuberculosis control in people living with HIV/AIDS

OBJECTIVE

to analyze the offering of health actions and services for the control of tuberculosis for people living with HIV/AIDS being followed up in the Specialized Care Services for HIV/AIDS in Ribeirão Preto, SP, Brazil.

METHOD

quantitative, exploratory survey study. Participated 253 people living with HIV/AIDS followed up by this service, considering as inclusion criteria: individuals older than 18 years living in the city and not inmates. Data collection was conducted from January 2012 to May 2013 through interviews with the support of a specific instrument. Data were analyzed using indicators and a composite index.

RESULTS

the offering of services for the control of tuberculosis in people living with HIV/AIDS by municipal services was considered as intermediate, reinforcing the need for better planning for comprehensive assistance, coordination of professionals in teams and among the services network, in addition to professional training and continuing education.

CONCLUSION

it is necessary to implement strategies that promote shared actions between TB and HIV / AIDS programs and between different services in order to strengthen the local care network, aimed at producing an individualized care, comprehensive and responsive.

OBJETIVO

analisar a oferta das ações e serviços de saúde para o controle da tuberculose nas pessoas vivendo com HIV/aids em seguimento pelos Serviços de Atenção Especializada ao HIV/aids de Ribeirão Preto, SP, Brasil.

MÉTODO

estudo quantitativo, exploratório, do tipo inquérito. Participaram 253 pessoas vivendo com HIV/aids em seguimento nos serviços, considerando os critérios de inclusão: indivíduos maiores de 18 anos, residentes no município e não pertencentes ao sistema prisional. A coleta de dados foi realizada no período de janeiro/2012 a maio/2013, por meio de entrevistas com apoio de um instrumento específico. Os dados foram analisados mediante indicadores e índice composto.

RESULTADOS

a oferta de ações e serviços para o controle da tuberculose nas pessoas vivendo com HIV/aids pelos serviços do município foi considerada regular, reforçando a necessidade de melhor planejamento da assistência de forma integral, articulação dos profissionais nas equipes e entre os serviços da rede, além da formação profissional e educação permanente.

CONCLUSÃO

faz-se necessário a implementação de estratégias que favoreçam ações compartilhadas entre os programas de tuberculose e HIV/aids e entre os diferentes serviços, com o intuito de fortalecer a rede local de atenção objetivando a produção de um cuidado singular, integral e resolutivo.

OBJETIVO

analizar la oferta de acciones y servicios de salud para el control de la tuberculosis en las personas viviendo con VIH-SIDA acompañadas por los Servicios de Atención Especializada al VIH-SIDA de Ribeirao Preto, SP, Brasil.

MÉTODO

estudio cuantitativo, exploratorio, de tipo encuesta. Participaron 253 personas viviendo con VIH-SIDA seguidas por estos servicios, considerando como criterios de inclusión: individuos mayores de 18 años, residentes en el municipio y no ser del sistema de prisiones. La recolección de datos fue realizada en el periodo de enero de 2012 a mayo de 2013, por medio de entrevistas guiadas por un instrumento especifico. Los datos fueron analizados mediante indicadores y un índice compuesto.

RESULTADOS

la oferta de acciones y servicios para el control de la tuberculosis en personas viviendo con VIH-SIDA fue considerada intermedia, reforzando la necesidad de mejorar la planificación de la asistencia en forma integral, la articulación de los profesionales en los equipos y entre los servicios de la red, además de la formación profesional y la educación permanente.

CONCLUSIÓN

se hace necesaria la implementación de estrategias que favorezcan las acciones compartidas entre los programas de tuberculosis y VIH-SIDA y entre los diferentes servicios, con el fin de fortalecer la red local de atención para producir un cuidado personalizado, integral y resolutivo.

Risk factors for mortality among HIV-positive patients with and without active tuberculosis in Dar es Salaam, Tanzania

BACKGROUND

The aim of this study was to describe risk factors for mortality and clinical characteristics of HIV-infected patients with and without tuberculosis (TB) coinfection.

METHODS

A cohort of HIV-infected patients with CD4(+) T-cell counts of ≤200 cells/μl was recruited, consisting of 255 HIV-infected patients without active TB and 231 patients with active TB. All received a well-supervised treatment with an efavirenz-based HAART, and those coinfected with TB received appropriate anti-TB treatment. They were followed up for 48 weeks after HAART initiation.

RESULTS

Common presenting symptoms in HIV-only patients were fever (36.5%), headache (34.5%), skin rash (34.5%) and weight loss (32%), while in HIV-TB patients the symptoms were weight loss (58%), cough (57.6%), night sweats (44.6%) and fever (34.2%). HIV-TB patients had significantly lower body mass index, Karnofsky scores and haemoglobin levels compared to those infected with HIV only, despite similar baseline CD4(+) T-cell counts. Overall, 12 (4.7%) HIV patients developed TB and 7 (3%) HIV-TB patients had worsening of their TB symptoms during the study period. Mortality was similar in the two groups, being 10.9% (16 deaths per 100 person years) and 11.3% (17 deaths per 100 person years) in HIV-only and HIV-TB patients, respectively. Overall, more males (13.1%) died compared to females (9.6%). Predictors of mortality were presence of oral candidiasis, Kaposi's sarcoma, low Karnofsky score, and low baseline white blood cell and CD4(+) T-cell counts.

CONCLUSIONS

The outcomes following well-supervised treatment of HIV-TB patients are similar to those in patients with HIV alone. Predictors of mortality were those of advanced disease.

Anemia in adults with tuberculosis is associated with HIV and anthropometric status in Dar es Salaam, Tanzania

SETTING

Tuberculosis (TB) infected adults attending out-patient TB clinics in Dar es Salaam, Tanzania.

OBJECTIVE

To examine the association of anemia with human immunodeficiency virus (HIV) co-infection, indicators of socio-economic status (SES) and anthropometric status in TB-infected adults.

DESIGN

Cross-sectional data collection during screening for a clinical trial.

RESULTS

Overall, 750 females and 1693 males participated in this study, of whom respectively 49% and 24% were co-infected with HIV-1. Hemoglobin levels were significantly lower in females than in males and in HIV-positive than in HIV-negative participants. HIV co-infection in this antiretroviral-naïve population was also associated with severe anemia (hemoglobin < 85 g/l) in both women (prevalence ratio [PR] = 2.07, 95%CI 1.65-2.59) and men (PR 3.45, 95%CI 2.66-4.47). Although severe anemia was negatively associated with indicators of SES, especially in males, adjustment for SES indicators only marginally changed its association with HIV co-infection. In both sexes, anemia was inversely associated with anthropometric status, independently of HIV infection and SES.

CONCLUSION

Among TB-infected adults, anemia is strongly associated with HIV co-infection and anthropometric status, independently of SES indicators. As anemia is a risk factor for morbidity and mortality in both infections, the management of anemia in TB-HIV co-infected patients warrants special attention.

Immune responses to the enduring hypoxic response antigen Rv0188 are preferentially detected in Mycobacterium bovis infected cattle with low pathology

The DosR regulon and the Enduring Hypoxic Response (EHR) define a group of M. tuberculosis genes that are specifically induced in bacilli exposed in vitro to conditions thought to mimic the environment encountered by Mycobacteria during latent infection. Although well described in humans, latent mycobacterial infection in cattle remains poorly understood. Thus, the aim of this study was to identify antigens that may potentially disclose cattle with latent M. bovis infection. To this end, we initially screened 57 pools of overlapping peptides representing 4 DosR regulon and 29 EHR antigens for their ability to stimulate an immune response in whole blood from TB-reactor cattle using IFN-γ and IL-2 as readouts. All 4 DosR regulon proteins were poorly recognized (maximum responder frequency of 10%). For the EHR antigens, both IFN-γ and IL-2 revealed similar response hierarchies, with responder frequencies ranging from 54% down to 3% depending on the given EHR antigen. Furthermore, these results demonstrated that responses in the infected cattle were largely IFN-γ biased. To support the concept for their role in latency, we evaluated if EHR antigen responses were associated with lower pathology. The EHR antigen Rv0188 was recognised predominantly in animals presenting with low pathology scores, whereas responses to ESAT-6/CFP-10 or the other EHR antigens tested were prevalent across the pathology spectrum. However, when we determined the production of additional cytokines induced by the M. bovis antigens PPD-B or ESAT-6/CFP-10, we detected significantly greater PPD-B-induced production of the pro-inflammatory cytokine IL-1β in animals recognizing Rv0188 (i.e. those with limited or no pathology). Thus, these results are consistent with the idea that responses to Rv0188 may identify a subset of animals at early stages of infection or in which disease progression may be limited.

Pharmacokinetic interaction study of ritonavir-boosted saquinavir in combination with rifabutin in healthy subjects

The effect of multiple doses of rifabutin (150 mg) on the pharmacokinetics of saquinavir-ritonavir (1,000 mg of saquinavir and 100 mg of ritonavir [1,000/100 mg]) twice daily (BID) was assessed in 25 healthy subjects. Rifabutin reduced the area under the plasma drug concentration-time curve from 0 to 12 h postdose (AUC(0-12)), maximum observed concentration of drug in plasma (C(max)), and minimum observed concentration of drug in plasma at the end of the dosing interval (C(min)) for saquinavir by 13%, 15%, and 9%, respectively, for subjects receiving rifabutin (150 mg) every 3 days with saquinavir-ritonavir BID. No effects of rifabutin on ritonavir AUC(0-12), C(max), and C(min) were observed. No adjustment of the saquinavir-ritonavir dose (1,000/100 mg) BID is required when the drugs are administered in combination with rifabutin. The effect of multiple doses of saquinavir-ritonavir on rifabutin pharmacokinetics was evaluated in two groups of healthy subjects. In group 1 (n = 14), rifabutin (150 mg) was coadministered every 3 days with saquinavir-ritonavir BID. The AUC(0-72) and C(max) of the active moiety (rifabutin plus 25-O-desacetyl-rifabutin) increased by 134% and 130%, respectively, compared with administration of rifabutin (150 mg) once daily alone. Rifabutin exposure increased by 53% for AUC(0-72) and by 86% for C(max). In group 3 (n = 13), rifabutin was coadministered every 4 days with saquinavir-ritonavir BID. The AUC(0-96) and C(max) of the active moiety increased by 60% and 111%, respectively, compared to administration of 150 mg of rifabutin once daily alone. The AUC(0-96) of rifabutin was not affected, and C(max) increased by 68%. Monitoring of neutropenia and liver enzyme levels is recommended for patients receiving rifabutin with saquinavir-ritonavir BID.

Application of nanotechnologies for improved immune response against infectious diseases in the developing world

There is an urgent need for new strategies to combat infectious diseases in developing countries. Many pathogens have evolved to elude immunity and this has limited the utility of current therapies. Additionally, the emergence of co-infections and drug resistant pathogens has increased the need for advanced therapeutic and diagnostic strategies. These challenges can be addressed with therapies that boost the quality and magnitude of an immune response in a predictable, designable fashion that can be applied for wide-spread use. Here, we discuss how biomaterials and specifically nanoscale delivery vehicles can be used to modify and improve the immune system response against infectious diseases. Immunotherapy of infectious disease is the enhancement or modulation of the immune system response to more effectively prevent or clear pathogen infection. Nanoscale vehicles are particularly adept at facilitating immunotherapeutic approaches because they can be engineered to have different physical properties, encapsulated agents, and surface ligands. Additionally, nanoscaled point-of-care diagnostics offer new alternatives for portable and sensitive health monitoring that can guide the use of nanoscale immunotherapies. By exploiting the unique tunability of nanoscale biomaterials to activate, shape, and detect immune system effector function, it may be possible in the near future to generate practical strategies for the prevention and treatment of infectious diseases in the developing world.

Global transcriptome analysis of the Mycobacterium bovis BCG response to sodium hypochlorite

Tuberculosis is a common and often deadly infectious disease caused by mycobacteria, mainly Mycobacterium tuberculosis and infrequently by other subspecies of the M. tuberculosis complex, such as M. bovis. Sodium hypochlorite (bleach) is routinely used in hospitals and health care facilities for surface sterilization; however, the modes of action of bleach on M. bovis BCG and how this organism develops resistance to sodium hypochlorite have not been elucidated. In this study, we performed a global toxicogenomic analysis of the M. bovis response to 2.5 mM sodium hypochlorite after 10 and 20 min. M. bovis BCG growth was monitored by measuring the quantity of ATP in picomoles produced over a short exposure time (10-60 min) to sodium hypochlorite. This study revealed significant regulation of oxidative stress response genes of M. bovis BCG, such as oxidoreductase, peroxidase, heat shock proteins and lipid transport, and metabolism genes. We interpreted this response as a potentially more lethal interplay between fatty acid metabolism, sulfur metabolism, and oxidative stress. Our results also suggest that sodium hypochlorite repressed transcription of genes involved in cell wall synthesis of M. bovis. This study shows that the treatment of M. bovis BCG with bleach inhibits the biosynthesis of outer cell wall mycolic acids and also induces oxidative damage.

Unexpected Hepatotoxicity of Rifampin and Saquinavir/Ritonavir in Healthy Male Volunteers

OBJECTIVES: Rifampin is a potent inducer of the cytochrome P450 3A4 isoenzyme (CYP3A4) that metabolizes most protease inhibitor (PI) antiretrovirals. This study was designed to evaluate the steady-state pharmacokinetics and tolerability of the coadministration of the PIs saquinavir and ritonavir (a CYP3A4 inhibitor used as a pharmacoenhancer of other PIs) and rifampin when coadministered in healthy HIV-negative volunteers. METHODS: In an open-label, randomized, one sequence, two-period crossover study involving 28 healthy HIV-negative volunteers, arm 1 was randomized to receive saquinavir/ritonavir 1000/100 mg twice daily while arm 2 received rifampin 600 mg once daily for 14 days. Both arms were then to receive concomitant saquinavir/ritonavir and rifampin for 2 additional weeks. Vital signs, electrocardiography, laboratory analyses, and blood levels of total saquinavir, ritonavir, rifampin, and desacetyl-rifampin, the primary metabolite of rifampin, were measured. RESULTS: In arm 1, 10/14 (71%) and, in arm 2, 11/14 (79%) participants completed the first study phase; eight participants in arm 1 and nine in arm 2 went on to receive both saquinavir/ritonavir and rifampin. Following substantial elevations (>/= grade 2) in hepatic transaminases in participants receiving the coadministered agents, the study was discontinued prematurely. Two participants in arm 1 displayed moderate elevations after five and four doses of rifampin, respectively. In arm 2, all participants experienced severe elevations within 4 days of initiating saquinavir/ritonavir. Clinical symptoms (e.g., nausea, vomiting, abdominal pain, and headache) were more common and severe in arm 2. Clinical symptoms abated and transaminases normalized following drug discontinuation. Limited pharmacokinetic data suggest a possible relationship between transaminase elevation and elevated rifampin and desacetyl-rifampin concentrations. CONCLUSIONS: Although not confirmed in HIV-infected patients, the data indicate that rifampin should not be coadministered with saquinavir/ritonavir.

Immunisation with BCG and recombinant MVA85A induces long-lasting, polyfunctional Mycobacterium tuberculosis-specific CD4+ memory T lymphocyte populations

In the search for effective vaccines against intracellular pathogens such as HIV, tuberculosis and malaria, recombinant viral vectors are increasingly being used to boost previously primed T cell responses. Published data have shown prime-boost vaccination with BCG-MVA85A (modified vaccinia virus Ankara expressing antigen 85A) to be highly immunogenic in humans as measured by ex vivo IFN-gamma ELISPOT. Here, we used polychromatic flow cytometry to investigate the phenotypic and functional profile of these vaccine-induced Mycobacterium tuberculosis (M.tb) antigen 85A-specific responses in greater detail. Promisingly, antigen 85A-specific CD4(+) T cells were found to be highly polyfunctional, producing IFN-gamma, TNF-alpha, IL-2 and MIP-1beta. Surface staining showed the responding CD4(+) T cells to be relatively immature (CD45RO(+) CD27(int)CD57(-)); this observation was supported by the robust proliferative responses observed following antigenic stimulation. Furthermore, these phenotypic and functional properties were independent of clonotypic composition and epitope specificity, which was maintained through the different phases of the vaccine-induced immune response. Overall, these data strongly support the use of MVA85A in humans as a boosting agent to expand polyfunctional M.tb-specific CD4(+) T cells capable of significant secondary responses.

The 6-kilodalton early secreted antigenic target-responsive, asymptomatic contacts of tuberculosis patients express elevated levels of interleukin-4 and reduced levels of gamma interferon

It is well known that the majority of healthy individuals exposed to Mycobacterium tuberculosis do not become clinically ill. We have previously shown that in recently exposed healthy contacts of tuberculosis (TB) patients, a strong immune response to the M. tuberculosis 6-kDa early secreted antigenic target (ESAT-6) virulence factor correlated with a higher risk of subsequent disease, although the mechanism was unclear at that time. Inspired by recent reports that elevated expression of interleukin-4 (IL-4) in health care workers exposed to M. tuberculosis also correlated with a higher risk of their subsequently developing disease, we examined expression of IL-4, its competitive antagonist IL-4delta2, and gamma interferon (IFN-gamma) in healthy household contacts of TB patients from Ethiopia. We then compared cytokine expression to their recognition of ESAT-6 (which is largely restricted to members of the tuberculosis complex and which serves as a reliable marker of infection) or to Ag85A (an antigen that is conserved among the mycobacteria and serves as a nonspecific control). Our study shows that in these recently exposed individuals, there is a correlation between a strong response to ESAT-6 and elevated expression of IL-4. Further, elevated expression of IL-4 is associated with lower expression of its antagonistic splice variant IL-4delta2 and with the Th1 cytokine IFN-gamma, suggesting that in these at-risk individuals, immunity is skewed away from a protective Th1 response, even before the development of clinical symptoms.

Recognition of stage-specific mycobacterial antigens differentiates between acute and latent infections with Mycobacterium tuberculosis

Mycobacterium tuberculosis is estimated to infect 80 to 100 million people annually, the majority of whom do not develop clinical tuberculosis (TB) but instead maintain the infection in a latent state. These individuals generally become positive in response to a tuberculin skin test and may develop clinical TB at a later date, particularly if their immune systems are compromised. Latently infected individuals are interesting for two reasons. First, they are an important reservoir of M. tuberculosis, which needs to be considered for TB control. Second, if detected prior to recrudescence of the disease, they represent a human population that is making a protective immune response to M. tuberculosis, which is very important for defining correlates of protective immunity. In this study, we show that while responsiveness to early secretory antigenic target 6 is a good marker for M. tuberculosis infection, a strong response to the 16-kDa Rv2031c antigen (HspX or alpha-crystallin) is largely restricted to latently infected individuals, offering the possibility of differential immunodiagnosis of, or therapeutic vaccination against, TB.

New models for the study of Mycobacterium-host interactions

The outcome of Mycobacterium infection is determined by a series of complex interactions between the bacteria and host immunity. Traditionally, mammalian models and cultured cells have been used to study these interactions. Recently, ameba (Dictyostelium), fruit flies (Drosophila) and zebrafish, amenable to forward genetic screens, have been developed as models for mycobacterial pathogenesis. Infection of these hosts with mycobacteria has allowed the dissection of intracellular trafficking pathways (Dictyostelium) and the roles of phagocytic versus antimicrobial peptide responses (Drosophila). Real-time visualization of the optically transparent zebrafish embryo/larva has elucidated mechanisms by which Mycobacterium-infected leukocytes migrate and subsequently aggregate into granulomas, the hallmark pathological structures of tuberculosis.