Household ventilation and tuberculosis transmission in Kampala, Uganda.

OBJECTIVE: To test the feasibility of measuring household ventilation and evaluate whether ventilation is associated with tuberculosis (TB) in household contacts in Kampala, Uganda. DESIGN: Adults with pulmonary TB and their household contacts received home visits to ascertain social and structural household characteristics. Ventilation was measured in air changes per hour (ACH) in each room by raising carbon dioxide (CO2) levels using dry ice, removing the dry ice, and measuring changes in the natural log of CO2 (lnCO2) over time. Ventilation was compared in homes with and without co-prevalent TB. RESULTS: Members of 61 of 66 (92%) households approached were enrolled. Households averaged 5.4 residents/home, with a median of one room/home. Twelve homes (20%) reported co-prevalent TB in household contacts. Median ventilation for all rooms was 14 ACH (interquartile range [IQR] 10-18). Median ventilation was 12 vs. 15 ACH in index cases' sleeping rooms in households with vs. those without co-prevalent TB (P = 0.12). Among smear-positive indexes not infected by the human immunodeficiency virus (HIV), median ventilation was 11 vs. 17 ACH in index cases' sleeping rooms in homes with vs. those without co-prevalent TB (P = 0.1). CONCLUSION: Our findings provide evidence that a simple CO2 decay method used to measure ventilation in clinical settings can be adapted to homes, adding a novel tool and a neglected variable, ventilation, to the study of household TB transmission.

Incidence of major clinical outcomes in a cohort of Ugandan and Zimbabwean women with HIV-1 infection followed from seroconversion.

We conducted a prospective cohort study of 306 HIV-1-infected women, followed from seroconversion for median 6.4 years in Uganda (UG) and Zimbabwe (ZM) to describe the incidence of major clinical outcomes (MCOs), defined as World Health Organization stage 4 conditions and any tuberculosis (TB). In Uganda, 19 MCOs occurred in 13 participants at median 4.6 years and a median CD4 count of 213 cells/mm(3). In Zimbabwe, 29 MCOs occurred in 27 participants at median 4.0 years (P < 0.001 versus UG) and median CD4 count of 219 cells/mm(3) (P = 0.83 versus UG). MCO incidence was not statistically different (UG: 2.82 cases/100 person-years versus ZM: 2.45; P = 0.64) except for TB (UG: 0.59 versus ZM: 2.02 cases/100 person-years; P = 0.02). This significant difference in TB incidence is primarily due to a TB screening and isoniazid prevention therapy programme that was implemented in Uganda, but not in Zimbabwe, highlighting the importance of integrated TB screening and treatment within HIV programmes.

Predictors of treatment failure among pulmonary tuberculosis patients in Mulago hospital, Uganda.

INTRODUCTION: Early identification of Tuberculosis (TB) treatment failure using cost effective means is urgently needed in developing nations. The study set out to describe affordable predictors of TB treatment failure in an African setting. OBJECTIVE: To determine the predictors of treatment failure among patients with sputum smear positive pulmonary TB at Mulago hospital. The study was carried out in the TB clinic of Mulago hospital Kampala, Uganda. This was an unmatched case control study where fifty patients with a diagnosis of TB treatment failure (cases) and 100 patients declared cured after completing anti TB treatment (controls) were recruited into the study. Cases were compared with controls to determine predictors of treatment failure. RESULTS: Significant predictors of treatment failure in this study included a positive sputum smear at 2 months of TB treatment (OR 20.63, 95%CI 5.42- 78.41) and poor adherence to anti TB treatment (OR 14.59, 95%CI 3.04-70.15). CONCLUSION: This study identified a treatment related and a simple laboratory predictor of TB treatment failure in Mulago hospital which may be used in resource limited settings for early recognition of those at risk and early intervention.

A randomized trial of punctuated antiretroviral therapy in Ugandan HIV-seropositive adults with pulmonary tuberculosis and CD4⁺ T-cell counts of ≥ 350 cells/µL.

BACKGROUND: Optimal treatment of human immunodeficiency virus (HIV)-associated tuberculosis in patients with high CD4⁺ T-cell counts is unknown. Suppression of viral replication during therapy for tuberculosis may block effects of immune activation on T cells and slow HIV disease progression. METHODS: We conducted a randomized trial in 214 HIV-infected patients with active tuberculosis and CD4⁺ T-cell counts of ≥ 350 cells/µL to determine whether 6 months of antiretroviral therapy given during tuberculosis treatment would improve clinical outcomes. Subjects were randomized to receive 6 months of abacavir-lamivudine-zidovudine concurrent with tuberculosis therapy or delayed antiretroviral therapy. Endpoints were CD4⁺ T-cell counts of < 250 cells/µL, AIDS, or death. RESULTS: Intervention and comparison arms had similar median CD4⁺ counts (517 and 534 cells/µL, respectively) and HIV RNA levels (4.6 and 4.7 log10 copies/µL, respectively). Viral suppression was achieved in 86% of patients allocated to intervention. Seventeen subjects (15.6%) in the intervention arm developed study outcome compared to 25 subjects (22.8%) in the comparison arm (P = .17). Grade 3 or 4 adverse events were less frequent in the intervention arm. By 2 months, 90% of subjects in both arms were culture-negative for tuberculosis. CONCLUSIONS: Short-term antiretroviral therapy during tuberculosis treatment in patients with CD4⁺T-cell counts of >350 cells/µL was safe and associated with clinical benefits.

Acceptability of treatment of latent tuberculosis infection in newly HIV-infected young women in Uganda.

We studied the acceptability of isoniazid preventive therapy (IPT) in newly human immunodeficiency virus (HIV) infected Ugandan women. Women were followed in an out-patient clinic where they received HIV care including IPT. Of 52 women who were purified protein derivative-positive, 48 were eligible for IPT and 39 (81%) completed therapy. This completion rate was higher than reported in similar observational studies.

Significant variation in presentation of pulmonary tuberculosis across a high resolution of CD4 strata.

BACKGROUND: The human immunodeficiency virus (HIV) alters the presentation of pulmonary tuberculosis (PTB), but it remains unclear whether alterations occur at a CD4 cell threshold or throughout HIV infection. OBJECTIVE: To better understand the relationship between CD4 count and clinical and radiographic presentation of PTB. SETTING AND DESIGN: Initial presentations of culture-confirmed PTB patients evaluated at a Ugandan national TB referral center and an affiliated research unit were compared by HIV status and across 11 CD4 cell count strata: 0-50 to >500 cells/µl. RESULTS: A total of 873 HIV-infected PTB cases were identified. Among HIV-infected PTB cases with CD4 < 50, 21% had a normal chest X-ray (CXR) vs. 2% with CD4 > 500, with a continuous trend across CD4 strata (test for trend, P < 0.001). All radiographic manifestations of PTB displayed significant trends across CD4 strata. HIV-infected vs. non-HIV-infected patients had no significant difference in CXR findings of miliary patterns or pleural effusion at CD4 > 100, normal CXR or fibrosis at CD4 > 150, adenopathy at CD4 > 250, and cavitation or upper lung disease at CD4 > 300. Twenty-three per cent of co-infected cases with CD4 < 50 and 1% with CD4 > 500 had negative acid-fast bacilli (AFB) smears, with a significant trend between (P < 0.001). CONCLUSION: Variations in CXR appearance and AFB smear correlate with CD4 decline in significant, continuous trends.

Introduction of an in-house PCR for routine identification of M. tuberculosis in a low-income country.

SETTING: National Tuberculosis (TB) Treatment Centre, Makerere University Medical School and Joint Clinical Research Centre, Kampala, Uganda. OBJECTIVE: To evaluate the introduction of a polymerase chain reaction (PCR) based assay for identification of the Mycobacterium tuberculosis complex (MTC) into routine practice. DESIGN: Routine diagnostic specimens were processed and inoculated into Bactec 12B vials and monitored daily. At a growth index (GI) > or =10, 0.5 ml of the 12B broth was removed and assayed with PCR. The same 12B vial was analyzed using the Bactec NAP method at GI > or =500. Vials at various levels of GI were included. Recurrent cost and time required to perform PCR and NAP were compared. RESULTS: Initially, 71 specimens were analyzed; of these, 68 were NAP-positive while 69 were PCR-positive for MTC. PCR resulted in a 75% reduction in cost for a single test compared with Bactec NAP. PCR has been successfully incorporated into routine practice, and 432 samples have been analyzed. In addition, isolates from solid media were also well identified by PCR. With PCR, more samples can be analyzed at a time, it is faster and is less labor intensive. CONCLUSION: PCR is a reliable and cheaper alternative for the identification of MTC.

Comparison of intermittent ethambutol with rifampicin-based regimens in HIV-infected adults with PTB, Kampala.

BACKGROUND: The human immunodeficiency virus (HIV) is a key factor responsible for the high rates of tuberculosis (TB) in sub-Saharan Africa. Treatment of TB with rifampicin (R, RMP) containing short-course regimens is highly effective in HIV-infected adults. We conducted a study to compare the efficacy and safety of intermittent ethambutol (E, EMB) with two RMP-containing regimens to treat pulmonary TB in HIV-infected patients. SETTING: National Tuberculosis Treatment Centre, Mulago Hospital, Kampala, Uganda. DESIGN: This was a prospective cohort compared to two non-randomised control groups. The study group and the two control arms were treated with 2 months of isoniazid (H), RMP, pyrazinamide (Z) and EMB followed by 6 E3H3 for the study group and 4HR or 6HR for controls. RESULTS: Between April 1993 and March 2000, 136 patients were enrolled in the 2EHRZ/E3H3 arm, 147 in the 2EHRZ/4HR arm and 266 in the 2EHRZ/6HR arm. The relapse rate was 18.2 per 100 person-years observation (PYO) for the study regimen compared to 9.7/100 PYO (P = 0.0063) and 4.8/100 PYO (P = 0.0001) in patients treated with 2 EHRZ/4HR or 2EHRZ/6HR, respectively. CONCLUSION: The 2EHRZ/6E3H3 regimen is safe and effective but has a significant risk of relapse.

Stevens - Johnson syndrome due to nevirapine.

A 25-year-old HIV-infected woman participating in a study of the effects of hormonal contraception on HIV disease progression was started on antiretroviral therapy-Combivir & Nevirapine (NVP) on May 27, 2004. NVP was 200mg daily initially for two weeks to be increased to 200mg bid thereafter. On day twelve, she presented with a mild skin rash on the trunk, purulent conjunctivitis, pharyngitis and fever. She was treated symptomatically and sent home. The following day she returned with a generalized erythematous eruption. She was admitted to JCRC (Joint Clinical and Research Centre) on June 14 and was diagnosed with Stevens - Johnson syndrome (SJS). Antiretroviral therapy was stopped. By July 05, 2004, she had improved and was discharged. After recovery she was restarted on Combivir and Efavirenz and is subsequently doing well on this regimen.

Effect of Mycobacterium vaccae (SRL172) immunotherapy on radiographic healing in tuberculosis.

OBJECTIVE: Controlled trials have failed to show an effect of Mycobacterium vaccae immunotherapy on treatment outcome and mortality in patients with tuberculosis (TB); however, several studies have suggested improvement in radiographic clearing and resolution of cavitary disease. METHODS: To assess the effect of M. vaccae immunotherapy on radiographic healing in pulmonary TB, chest X-rays from three randomized placebo-controlled trials of M. vaccae given as a single injection during the first 2 weeks of treatment were interpreted by a single, masked assessor using a standard scheme. Endpoints were the overall degree of radiographic improvement or deterioration and changes in cavitary disease at the end of antituberculosis treatment and follow-up. RESULTS: Of 1018 patients (478 HIV-infected; 540 HIV-uninfected) with an end of treatment or end of follow-up X-ray analyzed, 496 received M. vaccae and 522 received placebo. There was no difference in radiographic improvement or deterioration or cavitary disease at the end of treatment or follow-up comparing the M. vaccae and placebo groups. Results were similar comparing HIV-infected and HIV-uninfected patients. CONCLUSION: Adjunctive immunotherapy of drug-susceptible pulmonary TB with M. vaccae during the first 2 weeks of treatment did not improve radiographic responses to treatment or resolution of cavitary disease.

The species Mycobacterium africanum in the light of new molecular markers.

The findings of recent studies addressing the molecular characteristics of Mycobacterium tuberculosis complex isolates have initiated a discussion on the classification of M. africanum, especially of those isolates originating from East Africa (cluster F, subtype II) and displaying phenotypic and biochemical characteristics more similar to those of M. tuberculosis. To further address this question, we analyzed a representative collection of 63 M. tuberculosis complex strains comprising 30 M. africanum subtype I strains, 20 M. africanum subtype II strains, 10 randomly chosen M. tuberculosis isolates, and type strains of M. tuberculosis, M. bovis, and M. africanum for the following biochemical and molecular characteristics: single-nucleotide polymorphisms (SNPs) in gyrB and narGHJI and the presence or absence of RD1, RD9, and RD12. For all molecular markers analyzed, subtype II strains were identical to the M. tuberculosis strains tested. In contrast, the subtype I strains as well as the M. africanum type strain showed unique combinations of SNPs in gyrB and genomic deletions (the absence of RD9 and the presence of RD12), which proves their independence from M. tuberculosis and M. bovis. Accordingly, all subtype I strains displayed main biochemical characteristics included in the original species description of M. africanum. We conclude that the isolates from West Africa were proved to be M. africanum with respect to the phenotypic and genetic markers analyzed, while the isolates from East Africa must be regarded as phenotypic variants of M. tuberculosis (genotype Uganda). We propose the addition of the molecular characteristics defined here to the species description of M. africanum, which will allow clearer species differentiation in the future.

Tuberculosis in household contacts of infectious cases in Kampala, Uganda.

Tuberculosis remains a serious threat to public health, especially in sub-Saharan Africa. To determine the host and environmental factors responsible for tuberculosis in African households, the authors performed a prospective cohort study of 1,206 household contacts of 302 index cases with tuberculosis enrolled in Uganda between 1995 and 1999. All contacts were systematically evaluated for active tuberculosis and risk factors for active disease. Among the 1,206 household contacts, 76 secondary cases (6%) of tuberculosis were identified. Of these cases, 51 were identified in the baseline evaluation, and 25 developed during follow-up. Compared with index cases, secondary cases presented more often with minimal disease. The risk for secondary tuberculosis was greater among young children than adults (10% vs. 1.9%) and among human immunodeficiency virus-seropositive than -seronegative contacts (23% vs. 3.3%). Host risk factors could not be completely separated from the effects of environmental risk factors, suggesting that a household may represent a complex system of interacting risks for tuberculosis.

Immunogenicity of a recombinant human immunodeficiency virus (HIV)-canarypox vaccine in HIV-seronegative Ugandan volunteers: results of the HIV Network for Prevention Trials 007 Vaccine Study.

In the first preventative human immunodeficiency virus (HIV) vaccine study to be carried out in Africa, 40 HIV-seronegative Ugandan volunteers were randomly assigned to receive a canarypox vector containing HIV-1 clade B (env and gag-pro) antigens (ALVAC-HIV; n = 20), control vector containing the rabies virus glycoprotein G gene (n = 10), or saline placebo (n = 10). Cytotoxic T lymphocyte activity against target cells expressing clade A, B, and D antigens was assessed using standard chromium-release and confirmatory interferon-gamma enzyme-linked immunospot (ELISPOT) assays. Neutralizing antibody responses to cell line-adapted strains and primary isolates in all 3 clades were also tested. Twenty percent of vaccine recipients generated detectable cytolytic responses to either Gag or Env, and 45% had vaccine-induced HIV-specific CD8(+) T cell responses, as measured by the ELISPOT assay. In contrast, only 5% of the control group had vaccine-specific responses. Neutralizing antibodies against primary and laboratory-adapted HIV-1 clade B strains were seen in 10% and 15% of vaccine recipients, respectively, but responses against clades A and D were not detected. Although the immunogenicity of this clade B-based vaccine was low, ALVAC-HIV elicited CD8(+) T cell responses with detectable cross-activity against clade A and D antigens in a significant proportion of vaccine recipients.

Mycobacterium africanum subtype II is associated with two distinct genotypes and is a major cause of human tuberculosis in Kampala, Uganda.

The population structure of 234 Mycobacterium tuberculosis complex strains obtained during 1995 and 1997 from tuberculosis patients living in Kampala, Uganda (East Africa), was analyzed by routine laboratory procedures, spoligotyping, and IS6110 restriction fragment length polymorphism (RFLP) typing. According to biochemical test results, 157 isolates (67%) were classified as M. africanum subtype II (resistant to thiophen-2-carboxylic acid hydrazide), 76 isolates (32%) were classified as M. tuberculosis, and 1 isolate was classified as classical M. bovis. Spoligotyping did not lead to clear differentiation of M. tuberculosis and M. africanum, but all M. africanum subtype II isolates lacked spacers 33 to 36, differentiating them from M. africanum subtype I. Moreover, spoligotyping was not sufficient for differentiation of isolates on the strain level, since 193 (82%) were grouped into clusters. In contrast, in the IS6110-based dendrogram, M. africanum strains were clustered into two closely related strain families (Uganda I and II) and clearly separated from the M. tuberculosis isolates. A further characteristic of both M. africanum subtype II families was the absence of spoligotype spacer 40. All strains of family I also lacked spacer 43. The clustering rate obtained by the combination of spoligotyping and RFLP IS6110 analysis was similar for M. africanum and M. tuberculosis, as 46% and 49% of the respective isolates were grouped into clusters. The results presented demonstrate that M. africanum subtype II isolates from Kampala, Uganda, belong to two closely related genotypes, which may represent unique phylogenetic branches within the M. tuberculosis complex. We conclude that M. africanum subtype II is the main cause of human tuberculosis in Kampala, Uganda.

An investigation of suspected exogenous reinfection in tuberculosis patients in Kampala, Uganda.

Exogenous reinfection with Mycobacterium tuberculosis is an important phenomenon that occurs with unknown frequency in both immunocompromised and immunocompetent persons. As previous investigations suggest that exogenous reinfection can occur in both of these populations, we reviewed data for 40 cases of suspected TB relapse in an attempt to determine the frequency of this phenomenon in patients treated at the TB Research Unit in Kampala, Uganda. Our findings suggest that while this entity can occur in immunocompetent persons, immunocompromised persons are probably at higher risk for exogenous reinfection with M. tuberculosis.

Severity of human immunodeficiency virus infection is associated with decreased phase angle, fat mass and body cell mass in adults with pulmonary tuberculosis infection in Uganda.

Although coinfection with tuberculosis and human immunodeficiency virus (HIV) is emerging as a major problem in many developing countries, nutritional status has not been well characterized in adults with tuberculosis and HIV infection. We compared nutritional status between 261 HIV-positive and 278 HIV-negative adults with pulmonary tuberculosis in Kampala, Uganda, using anthropometry and bioelectrical impedance analysis. Among 163 HIV-positive and 199 HIV-negative men, intracellular water-to-extracellular water (ICW:ECW) ratio was 1.48 +/- 0.26 and 1.59 +/- 0.48 (P = 0.006) and phase angle was 5.42 +/- 1.05 and 5.76 +/- 1.30 (P = 0.009), respectively. Among 98 HIV-positive and 79 HIV-negative women, ICW:ECW was 1.19 +/- 0.16 and 1.23 +/- 0.15 (P = 0.11) and phase angle was 5.35 +/- 1.27 and 5.43 +/- 0.93 (P = 0.61), respectively. There were no significant differences in BMI, body cell mass, fat mass or fat-free mass between HIV-positive and HIV-negative adults. Among HIV-positive subjects, BMI, ICW:ECW, body cell mass, fat mass and phase angle were significantly lower among those with CD4(+) lymphocytes < or = 200 cells/microL compared with those who had > 200 cells/microL. In sub-Saharan Africa, coinfection with pulmonary tuberculosis and HIV is associated with smaller body cell mass and intracellular water, but not fat-free mass, and by large differences in ICW:ECW and phase angle alpha.

Increased replication of HIV-1 at sites of Mycobacterium tuberculosis infection: potential mechanisms of viral activation.

Tuberculosis (TB) enhances HIV-1 replication and the progression to AIDS in dually infected patients. We employed pleural TB as a model to understand the interaction of the host with HIV-1 during active TB, at sites of Mycobacterium tuberculosis (MTB) infection. HIV-1 replication was enhanced both in the cellular (pleural compared with blood mononuclear cells) and acellular (pleural fluid compared with plasma) compartments of the pleural space. Several potential mechanisms for expansion of HIV-1 in situ were found, including augmentation in expression of tumor necrosis factor (TNF)-alpha and the HIV-1 noninhibitory beta-chemokine (MCP-1), low presence of HIV-1 inhibitory beta-chemokines (MIP-1 alpha, MIP-1 beta, and RANTES [regulated on activation, normal T expressed and secreted]), and upregulation in expression of the HIV-1 coreceptor, CCR5, by pleural fluid mononuclear cells. Thus, at sites of MTB infection, conditions are propitious both for transcriptional activation of HIV-1 in latently infected mononuclear cells, and facilitation of viral infection of newly recruited cells. These mechanisms may contribute to enhanced viral burden and dissemination during TB infection.

Duration of efficacy of treatment of latent tuberculosis infection in HIV-infected adults.

BACKGROUND: Treatment of latent infection is needed to protect HIV-infected individuals against tuberculosis. A previous report addressed short-term efficacy of three regimens in HIV-infected adults. We now report on long-term efficacy of the study regimens. METHODS: Three daily self-administered regimens were compared in a randomized placebo-controlled trial in 2736 purified protein derivative (PPD)-positive and anergic HIV-infected adults. PPD-positive subjects were treated with isoniazid (INH) for 6 months (6H), INH plus rifampicin for 3 months (3HR), INH plus rifampicin and pyrazinamide for 3 months (3HRZ), or placebo for 6 months. Anergic subjects were randomized to 6H or placebo. RESULTS: 6H initially protected against tuberculosis in PPD-positive individuals; however, benefit was lost within the first year of treatment. Sustained benefit was observed in persons receiving 3HR and 3HRZ. In a Cox regression analysis, the adjusted relative risk for tuberculosis compared with placebo was 0.67 [95% confidence interval (CI), 0.42-1.07] for 6H, 0.49 (95% CI, 0.29-0.82) for 3HR, and 0.41 (95% CI, 0.22-0.76) for 3HRZ. When the rifampicin-containing regimens were combined, the adjusted relative risk for tuberculosis compared with placebo was 0.46 (95% CI, 0.29-0.71). Among anergic subjects, a modest degree of protection with 6H was present (adjusted relative risk, 0.61; 95% CI, 0.32-1.16). Treatment of latent tuberculosis infection had no effect on mortality. CONCLUSION: Six months of INH provided short-term protection against tuberculosis in PPD-positive HIV-infected adults. Three month regimens including INH plus rifampicin or INH, rifampicin and pyrazinamide provided sustained protection for up to 3 years.

Evaluation of suspected tuberculous pleurisy: clinical and diagnostic findings in HIV-1-positive and HIV-negative adults in Uganda.

SETTING: National Tuberculosis Treatment Centre, Mulago Hospital, Kampala, Uganda. OBJECTIVES: To compare clinical and radiographic presentation, and diagnostic methods, in adults with tuberculous pleurisy who are negative and positive for the human immunodeficiency virus (HIV). DESIGN: Adults with suspected pleural tuberculosis were screened by clinical examination, thoracocentesis and closed pleural biopsy. Biopsy material was cultured on Middlebrook 7H-10 solid medium and in BACTEC 12B radiometric vials. Pleural fluid was cultured using Löwenstein-Jensen slants, BACTEC and Kirchner liquid medium. RESULTS: Of 156 individuals enrolled, 142 had tuberculosis, of whom 80% were HIV-positive. Among those with tuberculosis, HIV-positive patients bad a more severe and longer illness. The size of effusions was similar in HIV-positive and HIV-negative patients. A higher proportion of HIV-positive patients had parenchymal infiltrates but this difference was not statistically significant. Pleural fluid lymphocytosis was present in all HIV-negative and 97% of the HIV-positive patients. HIV-positive patients had lower pleural fluid lymphocyte counts. Pleural fluid cultures were more often positive in HIV-positive patients. BACTEC and Kirchner liquid media gave higher yields than solid media. CONCLUSION: HIV-positive patients with tuberculous pleurisy had a more severe illness than HIV-negative patients. Mycobacterial cultures from HIV-positive patients were more often positive, suggesting more mycobacterial extension from the lungs into the pleural space. Liquid culture media were superior to solid media with regard to diagnostic yield and time until diagnosis.