Pulmonary tuberculosis in Guinea-Bissau: clinical and bacteriological findings, human immunodeficiency virus status and short term survival of hospitalized patients

The Guinea-Bissau family of Mycobacterium tuberculosis complex revisited

The Guinea-Bissau family of strains is a unique group of the Mycobacterium tuberculosis complex that, although genotypically closely related, phenotypically demonstrates considerable heterogeneity. We have investigated 414 M. tuberculosis complex strains collected in Guinea-Bissau between 1989 and 2008 in order to further characterize the Guinea-Bissau family of strains. To determine the strain lineages present in the study sample, binary outcomes of spoligotyping were compared with spoligotypes existing in the international database SITVIT2. The major circulating M. tuberculosis clades ranked in the following order: AFRI (n = 195, 47.10%), Latin-American-Mediterranean (LAM) (n = 75, 18.12%), ill-defined T clade (n = 53, 12.8%), Haarlem (n = 37, 8.85%), East-African-Indian (EAI) (n = 25, 6.04%), Unknown (n = 12, 2.87%), Beijing (n = 7, 1.68%), X clade (n = 4, 0.96%), Manu (n = 4, 0.97%), CAS (n = 2, 0.48%). Two strains of the LAM clade isolated in 2007 belonged to the Cameroon family (SIT61). All AFRI isolates except one belonged to the Guinea-Bissau family, i.e. they have an AFRI_1 spoligotype pattern, they have a distinct RFLP pattern with low numbers of IS6110 insertions, and they lack the regions of difference RD7, RD8, RD9 and RD10, RD701 and RD702. This profile classifies the Guinea-Bissau family, irrespective of phenotypic biovar, as part of the M. africanum West African 2 lineage, or the AFRI_1 sublineage according to the spoligtyping nomenclature. Guinea-Bissau family strains display a variation of biochemical traits classically used to differentiate M. tuberculosis from M. bovis. Yet, the differential expression of these biochemical traits was not related to any genes so far investigated (narGHJI and pncA). Guinea-Bissau has the highest prevalence of M. africanum recorded in the African continent, and the Guinea-Bissau family shows a high phylogeographical specificity for Western Africa, with Guinea-Bissau being the epicenter. Trends over time however indicate that this family of strains is waning in most parts of Western Africa, including Guinea-Bissau (p = 0.048).

Higher mortality in HIV-2/HTLV-1 co-infected patients with pulmonary tuberculosis in Guinea-Bissau, West Africa, compared to HIV-2-positive HTLV-1-negative patients

OBJECTIVES

To investigate the effect of human T-lymphotropic virus type 1 (HTLV-1) on CD4 counts and mortality in tuberculosis (TB) patients with or without human immunodeficiency virus (HIV).

METHODS

A prospective study on 280 hospitalized patients with pulmonary TB was performed in Guinea-Bissau, 1994-1997, including HIV, CD4 counts and clinical outcome. We compared the CD4 count levels at the time of inclusion between HIV-negative and HIV-positive patients, with or without HTLV-1. Mortality was determined while patients were on treatment for TB.

RESULTS

Median CD4% was significantly higher in HIV-positive subjects co-infected with HTLV-1 compared to HTLV-1-negative patients. Two hundred thirty-three individuals were included in the analysis of mortality, and among HIV-negative subjects the mortality was 18.6/100 person-years . In HIV-2-positive HTLV-1-negative subjects the mortality was 39.5/100 person-years and in HIV-2/HTLV-1 co-infected patients it was 113.6/100 person-years (adjusted mortality rate ratio 4.7, 95% CI 1.5-14.4; p < 0.01). When all HIV-positive patients were analyzed together, corresponding mortality rates were 53.5/100 person-years and 104.8/100 person-years , respectively (not significant).

CONCLUSIONS

HIV/HTLV-1 co-infected patients hospitalized for pulmonary TB had a high mortality and had significantly higher CD4% compared to only HIV-positive subjects. This may imply that HTLV-1 has an adverse effect on the immune system in HIV-infected subjects, independently of the CD4 count, that makes co-infected subjects more vulnerable to TB.

Genetic diversity in clinical isolates of Mycobacterium avium complex from Guinea-Bissau, West Africa

Isolates of Mycobacterium avium complex (MAC) were cultured from sputum samples obtained from patients in Guinea-Bissau, West Africa. Twenty-eight isolates hybridising with MAC probe (AccuProbe) were further characterised by different molecular techniques: hybridisation with species-specific probes (AccuProbe) for M. avium and M. intracellulare, partial sequencing of 16S rRNA gene and PCR detection of the DT1-DT6 sequences and the macrophage-induced gene (mig). Only one of the 28 isolates reacted with the M. avium probe and four with the M. intracellulare probe. Two isolates expressed the DT1 sequence, and three the DT6. The mig was detected in 18 (64%) of the isolates. Sequencing of 16S rRNA had the greatest discriminative power of the typing methods applied, without strong correlation with any other technique. Clinical MAC isolates from Guinea-Bissau demonstrated a wide genetic diversity among the members of M. avium complex that might reflect on biotope variation.

Incidence of tuberculosis and survival after its diagnosis in patients infected with HIV-1 and HIV-2

BACKGROUND

In sub-Saharan Africa, tuberculosis (TB) is the most frequently diagnosed opportunistic infection and cause of death among HIV-infected patients. HIV-2 has been associated with less immune suppression, slower disease progression and longer survival.

OBJECTIVE

To examine whether the incidence of TB and survival after TB are associated with CD4 cell count rather than HIV type.

METHODS

Clinical and immunological data were retrospectively evaluated among an open clinic-based cohort of HIV-1- and HIV-2-infected patients to determine incidence of TB (first diagnosis > 28 days after HIV diagnosis) and subsequent mortality. Patients were grouped by CD4 cell count into those with < 200, 200-500 and > 500 x 10 cells/l.

RESULTS

Incident TB was diagnosed among 159 of 2012 patients, with 4973 person-years of observation time. In 105/159 (66.0%), the diagnosis was confirmed by direct microscopy or culture. Incidence of TB was highest in the group with < 200 x 10 cells/l (9.1/100 and 8.8/100 person-years in HIV-1 and HIV-2, respectively). Adjusted for CD4 cell count, there was no significant difference in incidence or mortality following TB between HIV-1- and HIV-2-infected patients. Mortality rate was higher in those with incident TB and HIV infection, most markedly in the group with the highest CD4 cell count (hazard ratio, 10.0; 95% confidence interval, 5.1-19.7).

CONCLUSION

Adjusted for CD4 cell count, incidence of TB was similar among HIV-1- and HIV-2-infected patients. Mortality rates after TB diagnosis were similar in both groups and high compared with those without TB.

Baciloscopia de escarro em pacientes internados nos hospitais de tuberculose do Estado de São Paulo

Foram averiguadas as fichas preenchidas com informações de pacientes, internados em hospitais especializados de tuberculose, com prévia autorização da equipe da Secretaria de Estado da Saúde de São Paulo, entre 1984 e 1997. Realizou-se um estudo retrospectivo e descritivo, visando analisar as associações da baciloscopia com as variáveis: sexo, faixa etária, Unidade de Saúde, exame radiológico de tórax, motivo clínico ou social da internação, tempo da internação e o tipo de saída do hospital, para subsídio deste e de outros estudos. Entre os internados, 35.510 (95,5%) apresentavam a forma pulmonar da doença, e 25.477 (71,8%) haviam realizado a baciloscopia de escarro. Observou-se que em 79.4% o resultado foi positivo, sendo 79.6% do sexo masculino. Os pacientes do sexo masculino, com baciloscopia positiva, foram predominantes em quase todas as faixas etárias, exceto na de 5 a 14 anos. Os encaminhados pelo Centro de Saúde e pelo Hospital Geral, foram os que tiveram o maior percentual de baciloscopia positiva (85,4% e 83,7%, respectivamente). Os internados por falência de tratamento, foram os que tiveram uma maior positividade (91,2%). Em relação ao tempo de internação, quanto maior a permanência, maior a positividade da baciloscopia. Quanto ao tipo de saída, as indesejadas (por abandono, a pedido e as disciplinares) apresentaram maior positividade do escarro na admissão. A baciloscopia é essencial para a internação dos doentes de tuberculose, evitando internações equivocadas, sendo que os pacientes positivos merecem uma especial atenção, para que não ocorram as saídas indesejadas e os longos períodos de internação.

Community study of the relative impact of HIV-1 and HIV-2 on intrathoracic tuberculosis

BACKGROUND

HIV-1 infection is associated with an increased incidence of and mortality from tuberculosis. Few community studies have examined the effect of HIV-2 on tuberculosis.

METHODS

We investigated the association between HIV-1, HIV-2 and active tuberculosis in four districts (population 42 709) in Bissau, capital of Guinea-Bissau, with the highest known seroprevalence of HIV-2 infection in the world. From May 1996 to June 1998, tuberculosis surveillance and active case finding among contacts was conducted. Patients were HIV-tested, given specific tuberculosis treatment for 8 months and followed regarding mortality. Simultaneously, an HIV sero-survey was performed in a random sample of 1748 permanent residents.

RESULTS

During a 25-month period, 366 tuberculosis cases were identified. After excluding cases among visitors to the area, and adjusting for age, the incidence of tuberculosis was 18.3 times higher (95% CI 12.9-26.0) among HIV-1-positive individuals, 13.7 times higher (9.0-20.7) among dually infected (HIV-1 and HIV-2), and 3.0 times higher (2.1-4.3) among HIV-2-infected compared with HIV-negative individuals. HIV-1 and dually infected tuberculosis patients had a higher mortality rate than HIV-negative tuberculosis patients [mortality ratio (MR) 2.68; CI 1.11-6.48 and 2.89; CI 1.13-7.39, respectively]. The survival of HIV-2-positive tuberculosis patients was similar to that of HIV-negative tuberculosis patients (MR 1.19; CI 0.46-3.06).

CONCLUSION

The presence of HIV-2 infection increases the incidence of tuberculosis compared with that in non-HIV-infected individuals, but does not affect tuberculosis-related mortality in the short term. In contrast, the presence of HIV-1 infection, alone or with HIV-2, has a several-fold greater impact on both the incidence of and mortality from tuberculosis.

High mortality and severe immunosuppression in hospitalized patients with pulmonary tuberculosis and HIV-2 infection in Guinea-Bissau

The aim of this study was to prospectively compare the clinical outcomes in HIV-2-infected and HIV-negative patients with culture-confirmed pulmonary tuberculosis, evaluate immunological changes and investigate risk factors for decreased survival in HIV-2-positive subjects. From 1994 to 1997, 127 consecutive patients with pulmonary tuberculosis were included at the Raoul Follereau Hospital in Bissau, the capital of Guinea-Bissau. All subjects were initially hospitalized, and then followed to the end of the 8-month treatment period. CD4 T-lymphocyte counts were determined by flow cytometry before, during and at the end of the treatment period. The prevalences of HIV-1, HIV-2 and HIV-1/HIV-2 dual reactivity were 8.7%, 23.6% and 9.4%, respectively (95% confidence intervals 3.8-13.6, 16.2-31.0 and 4.4-14.5, respectively). The mortality rate during the study period was significantly higher in HIV-2-positive (p < 0.01) and HIV-1/HIV-2 dually reactive (p < 0.01) patients than in HIV-negative individuals (52.9, 83.3 and 8.7 per 100 person-years, respectively). In HIV-1-positive patients the mortality rate was 30.8/100 person-years (p = NS). Baseline total CD4 cell counts were 213, 104, 235 and 624 x 10(6)/l (% CD4 = 17, 15, 20 and 40) among HIV-1-, HIV-2- and HIV-1/HIV-2-positive and HIV-negative subjects, respectively. The median rates of change per year of total CD4 cell counts in HIV-2-positive and HIV-negative subjects were 66 and 340 x 10(6)/l, respectively (interquartile ranges -78-249 and 21-624). In conclusion, we found a significantly higher mortality rate in HIV-2-positive compared to HIV-negative individuals. Baseline CD4 cell counts were markedly suppressed and similar in all 3 HIV-positive groups, and in a multivariate logistic regression analysis a value of CD4 percentage of < 10 was shown to be an independent predictor of decreased survival in HIV-2-infected subjects.

Current issues in maternal and perinatal tuberculosis: impact of the HIV-1 epidemic

Human immunodeficiency virus type 1 (HIV-1) and tuberculosis (TB) are among the leading causes of disability and death in the developing world, the largest burden borne by sub-Saharan Africa and Asia. Both diseases are significant among women of childbearing age, and TB, although uncommon in pregnancy, is on the increase. While earlier reports were contradictory regarding the effect of TB on the course of pregnancy and vice versa, the negative impacts of each on the other have been documented, some in relation to HIV-1 co-infection. This review focuses on emerging data on maternal and perinatal TB within the context of HIV-1 infection.

Evolution and clonal traits of Mycobacterium tuberculosis complex in Guinea-Bissau

Two hundred twenty-nine consecutive isolates of Mycobacterium tuberculosis complex from patients with pulmonary tuberculosis in Guinea-Bissau, which is located in West Africa, were analyzed for clonal origin by biochemical typing and DNA fingerprinting. By using four biochemical tests (resistance to thiophene-2-carboxylic acid hydrazide, niacin production, nitrate reductase test, and pyrazinamidase test), the isolates could be assigned to five different biovars. The characteristics of four strains conformed fully with the biochemical criteria for M. bovis, while those of 85 isolates agreed with the biochemical criteria for M. tuberculosis. The remaining 140 isolates could be allocated into one of three biovars (biovars 2 to 4) representing a spectrum between the classical bovine (biovar 1) and human (biovar 5) tubercle bacilli. By using two genotyping methods, restriction fragment length polymorphism analysis with IS6110 (IS6110 RFLP analysis) and spoligotyping, the isolates could be separated into three groups (groups A to C) of the M. tuberculosis complex. Group A (n = 95), which contained the majority of classical human M. tuberculosis isolates, had large numbers of copies of IS6110 elements (mean number of copies, 9) and a distinctive spoligotyping pattern that lacked spacers 33 to 36. Isolates of the major group, group B (n = 119), had fewer IS6110 copies (mean copy number, 5) and a spoligotyping pattern that lacked spacers 7 to 9 and 39 and mainly comprised isolates of biovars 1 to 4. Group C isolates (n = 15) had one to three IS6110 copies, had a spoligotyping pattern that lacked spacers 29 to 34, and represented biovar 3 to 5 isolates. Four isolates whose biochemical characteristics conformed with those of M. bovis clustered with the group B isolates and had spoligotype patterns that differed from those previously reported for M. bovis, in that they possessed spacers 40 to 43. Interestingly, isolates of group B and, to a certain extent, also isolates of group C showed a high degree of variability in biochemical traits, despite genotypic identity in terms of IS6110 RFLP and spoligotype patterns. We hypothesize that isolates of groups B and C have their evolutionary origin in West Africa, while group A isolates are of European descent.

HIV and tuberculosis in rural sub-Saharan Africa: a cohort study with two year follow-up

The objective was to examine the effect of HIV seropositivity on outcomes in tuberculosis (TB) patients in a rural African setting, including rates of TB relapse, other morbid events and mortality. The study setting was a district level hospital in Mzuzu, Malawi. Adult TB patients presenting between November 1991 and May 1993 were included in the study. Treatment was given according to national guidelines. Patients with smear-positive TB received 8 months of rifampicin-containing short-course chemotherapy. Patients with smear-negative or extrapulmonary TB received 12 months of 'standard' treatment. Subjects were followed until they died or until the study concluded (December 1994). There were 225 eligible patients; 187 were tested for HIV and enrolled in the study (66.8% HIV seropositive). Ninety-four percent had complete follow-up information. The cure rate in smear-positive patients who survived to the end of treatment was over 90% and not significantly affected by HIV. Disorders of the gastrointestinal, neurological and dermatological systems were significantly more common in HIV-seropositive patients. HIV had a significant effect on the risk of relapse of TB (hazard ratio [HR] = 10.55 [95% CI 1.38, 80.93]) and on all-cause mortality (HR = 2.81 [95% CI 1.63, 4.64]). Despite high HIV prevalence, high rates of TB cure are achievable using the usual treatment protocols. However, excess TB relapse, other illnesses and mortality associated with HIV seropositivity have serious implications for TB control. There is an urgent need to identify effective intervention strategies aimed at prevention, early diagnosis and treatment of these illnesses.

A new, clinically-based algorithm for the diagnosis of HIV in African tuberculosis patients: cross-sectional analysis from Mzuzu, Malawi

We aimed to create an improved, clinically-based algorithm for the diagnosis of HIV in tuberculosis (TB) patients. Cross-sectional analysis was performed on data from adult TB patients consecutively diagnosed at a Malawian district level hospital. Of 225 patients, 187 with valid HIV results were included in the study. Sixty-seven per cent were HIV seropositive. Urban address, history of skin rash and sexually transmitted diseases (STDs) and, on examination, oral candidiasis and lymphadenopathy, were associated with HIV co-infection. Using these clinical characteristics, a case definition for HIV was constructed. The Mzuzu clinical case definition was highly sensitive (86%). The area under the receiver operating characteristic (ROC) curve was 0.81, significantly larger than existing World Health Organization (WHO) clinical case definitions. The Mzuzu definition is proposed for further evaluation in settings where HIV serological testing is not readily available.

Increased prevalence of HIV-2 infection in hospitalized patients with severe bacterial diseases in Guinea-Bissau

We studied the association between HIV-2 infection and bacterial pneumonia, sepsis or pyomyositis, as well as the influence of HIV-2 infection on the clinical outcome in patients with these bacterial infections. A total of 201 consecutive hospitalized patients were included at the Simao Mendes National Hospital in Bissau, Guinea-Bissau. Age- and sex-matched controls were selected from an ongoing census in a semi-urban area of Bissau. Among 201 cases with such bacterial infection the prevalence of HIV-1 was 5.4%, HIV-2, 27.9%, and both HIV-1 and HIV-2 reactivity 6.4%. Among controls, the corresponding prevalence rates were significantly lower, 1.5%, 9.0% and 1.0%, respectively. A total of 140, 31 and 30 cases of pneumonia, sepsis and pyomyositis were included, and the differences in prevalence of HIV-2 compared with the controls also remained significant for each diagnosis separately. Lymphocyte subsets were determined in 93 consecutive patients, and the CD4 cell counts and CD4/CD8 lymphocyte ratios were markedly suppressed in the HIV-2-seropositive group. Due to excess mortality in the seropositive groups with sepsis (75.0%) and pyomyositis (25.0%), the mortality during hospitalization was significantly higher among HIV-2 infected compared to HIV-negative patients. Among cases of pneumonia the mortality was low in the HIV-2-seropositive (2.9%) as well as in the HIV-seronegative (3.4%) group.