HIV infection in patients with tuberculosis in Kinshasa, Zaire

To better define the interrelationship of infection with human immunodeficiency virus (HIV) and tuberculosis (TB), we conducted three HIV serosurveys of inpatients and outpatients with confirmed or suspected TB in Kinshasa, Zaire. HIV seroprevalence in hospitalized sanatorium patients did not change significantly in serosurveys conducted in 1985 and 1987 (92/231 [40%] versus 85/234 [36%]). These proportions were significantly higher than the 17% HIV seroprevalence observed in a 1987 serosurvey of 509 consecutive patients with an initial diagnosis of pulmonary TB seen at an outpatient TB diagnostic center in Kinshasa (p less than 0.001). HIV seroprevalence was higher in sanatorium patients with extrapulmonary TB (22/46 [48%]) and suspected pulmonary TB (60/132 [45%]) than in patients with bacteriologically confirmed pulmonary TB (94/287 [33%]) (p less than 0.02). Mycobacterium sputum isolation rates were similar in HIV-seropositive (28/34 [82%]) and HIV-seronegative patients (135/159 [85%]). All isolates were Mycobacterium tuberculosis. Eighteen (21%) of 84 HIV-seropositive sanatorium patients in 1987, who were followed for two months after admission, had died, compared with 11 (9%) of 128 HIV-seronegative patients (p less than 0.01). However, clearance rates of acid-fast bacilli from sputum after standard therapy were equally good in HIV-seropositive and HIV-seronegative survivors. With the growing AIDS problem, the serious TB burden in sub-Saharan Africa may become even more onerous and may critically overload the stressed African health care systems.     

Transmission of tuberculosis in an endemic urban setting in Brazil.

SETTING: Two out-patient facilities in S?o Paulo, Brazil. OBJECTIVE: To study the transmission pattern of tuberculosis (TB) among human immunodeficiency virus (HIV) infected and uninfected persons in a setting endemic for TB. DESIGN: A prospective study comparing HIV-seropositive and -seronegative TB patients identified consecutively between 1 March 1995 and 1 April 1997. The patients were stratified according to their Mycobacterium tuberculosis isolate IS6110 RFLP patterns. Risk factors were sought for infection with an RFLP cluster pattern strain, inferred to represent recent transmission. RESULTS: Fifty-eight (38%) of 151 HIV-seropositive patients and 36 (25%) of 142 HIV-seronegative patients were infected with M. tuberculosis isolates that belonged to cluster patterns (OR 1.84, 95% CI 1.08-3.13). Multidrug-resistant (MDR) strains were isolated from 19 patients, all of whom were HIV seropositive; 12 (63%) of these, and 46 (35%) of 132 drug-susceptible isolates had cluster patterns (OR 3.20, 95% CI 1.08-9.77). CONCLUSION: In a TB-endemic urban setting in Brazil, the proportion of cases resulting from recent transmission appears to be greater among HIV-seropositive than among HIV-seronegative patients. A large proportion of MDR-TB (63%) cases was caused by strains that had cluster RFLP patterns, suggesting recent transmission of already resistant organisms. This type of knowledge regarding TB transmission may help to improve locally appropriate TB control programs.     

B-cell immune responses in HIV positive and HIV negative patients with tuberculosis evaluated with an ELISA using a glycolipid antigen

The diagnostic value of the PGL-Tb1 enzyme-linked immunosorbent assays (ELISA) was established following a survey study using sera from 220 Tuberculosis patients (including 69 HIV coinfected) and 324 controls. A higher percentage (76.8%) of the HIV-seropositive compared to the HIV-seronegative (58.9%) TB patients were ELISA positive (p=0.02) with a specificity of 94%. In HIV-positive TB patients, ELISA sensitivity was identical for all sites of disease and antibody levels were not affected by the CD4+ counts, PPD results, age or bacterial yield. Combining data for both the smear microscopy and ELISA maximized sensitivity. The kinetics of anti-PGL-Tb1 antibody was evaluated in cohort studies using sera collected before, during and after treatment for clinical TB for 79 TB patients (including 39 HIV coinfected). Statistically significant ELISA signals were observed in 51.3% of HIV-seropositive TB patients prior to the diagnosis of clinical TB and elevated antibody levels persisting 18 months after the end of antituberculous chemotherapy. Asymptomatic development of antibody also occurred in 22.7% of a cohort of 44 HIV-positive patients with a high risk of tuberculosis, but no correlation was found between persisting elevated antibody levels and progression to active disease. This antibody response in absence of disease, might reflect the control of an incipient tuberculosis infection by antituberculous prophylaxis or through an improved protective immune response associated with antiretroviral therapy.     

HIV infection and primary resistance to antituberculosis drugs in Abidjan, C?te d'Ivoire.

OBJECTIVE: To determine the prevalence of Mycobacterium tuberculosis resistance to antituberculosis drugs, and to relate this resistance to HIV serologic status. DESIGN: Cross-sectional prevalence study. SETTING: The two major outpatient tuberculosis clinics in Abidjan, C?te d'Ivoire, West Africa. PATIENTS: Sixty individuals with newly diagnosed pulmonary tuberculosis and sputum smears positive for acid-fast bacilli. MAIN OUTCOME MEASURES: HIV serologic status and in vitro testing for susceptibility of M. tuberculosis isolates to antituberculosis drugs. RESULTS: M. tuberculosis was isolated from 82% (49 out of 60) of sputum specimens. Thirty-five per cent (17 out of 49) were obtained from HIV-seropositive and 65% (32 out of 49) from HIV-seronegative patients. There was no statistically significant difference in the proportion of resistant isolates from HIV-seropositive versus HIV-seronegative patients, although the relatively small sample size limited power. Of the total number of isolates, 17% were resistant to isoniazid; resistance was less to streptomycin (7%), rifampin (2%), pyrazinamide (0%), and ethambutol (0%). Eighteen and 21% of mycobacterial isolates from HIV-seropositive and HIV-seronegative individuals, respectively, were resistant to one or more of these drugs. CONCLUSIONS: Surveys of this type are useful in planning and evaluating tuberculosis preventive therapy in individuals with dual infection.     

The potential impact of enhanced diagnostic techniques for tuberculosis driven by HIV: a mathematical model

OBJECTIVE: To explore the potential impact of enhanced tuberculosis (TB) diagnostic techniques as a TB control strategy in an adult population with high HIV prevalence. DESIGN: A compartmental difference-equation model of TB/HIV was developed using parameter estimates from the literature. METHODS: The impact of five TB control interventions (rapid molecular testing, mycobacterial culture, community-wide and HIV-targeted active case finding, and highly active antiretroviral therapy) on TB incidence, prevalence, and mortality was modeled in a steady-state population with an HIV prevalence of 17% and annual TB incidence of 409 per 100 000. Sensitivity analyses assessed the influence of each model parameter on the interventions' mortality impact. RESULTS: Enhanced diagnostic techniques (rapid molecular testing or culture) are each projected to reduce TB prevalence and mortality by 20% or more, an impact similar to that of active case-finding in 33% of the general community and greater than the effect achievable by case-finding or antiretroviral treatment efforts in HIV-positive patients alone. The projected impact of enhanced diagnostics on TB incidence (< 10% reduction) is smaller. The impact of TB diagnostics is sensitive to the quality of existing diagnostic standards and the level of access to diagnostic services, but is robust across a wide range of population parameters including HIV and TB incidence. CONCLUSIONS: Enhanced TB diagnostic techniques may have substantial impact on TB morbidity and mortality in HIV-endemic regions. As TB rates continue to increase in these areas, enhanced diagnostic techniques merit further consideration as TB control strategies.     

Comparison of mycobacterial lymphadenitis among persons infected with human immunodeficiency virus and seronegative controls.

Lymphadenitis is a common extrapulmonary manifestation of mycobacterial disease in persons with human immunodeficiency virus (HIV) infection. We compared the clinical, mycobacterial, and diagnostic characteristics of mycobacterial adenitis in 11 HIV-seropositive and 29 HIV-seronegative patients. Ninety-three percent of the HIV-seronegative patients and 54% of the HIV-seropositive patients were foreign-born. In contrast to the HIV-seronegative patients, seropositive patients were more likely to be febrile and have negative purified protein derivative skin tests and abnormal chest roentgenograms. Sputum samples were rarely diagnostic in either group. Mycobacterium tuberculosis was the most commonly isolated organism in both groups, although United States-born patients with HIV infection were more likely to be infected with nontuberculous mycobacteria. In contrast to results for seronegative patients, fine-needle aspiration was usually diagnostic in the HIV-seropositive population, especially in those at risk for M. tuberculosis infection. Similarly, the rate at which smears were positive for acid-fast bacilli was significantly higher in the HIV-seropositive group, a circumstance suggesting a higher burden of organisms in this population. Finally, although preceding opportunistic infections were uncommon in the HIV-seropositive group, both tuberculous and nontuberculous adenitis were associated with advanced immunosuppression.     

A retrospective cohort study of the risk of tuberculosis among women of childbearing age with HIV infection in Zaire

To determine the risk of active tuberculosis associated with HIV infection, we retrospectively studied a cohort of HIV-seropositive and HIV-seronegative women participating in an HIV perinatal transmission study in Kinshasa, Zaire. After a median follow-up of 32 months, new cases of proven pulmonary or clinically diagnosed tuberculosis occurred in 19 of the 249 HIV-seropositive women (7.6%, 3.1 cases per 100 person-years) compared with 1 of the 310 HIV-seronegative women (0.3%, 0.12 cases per 100 person-years), for a relative risk of 26 (95% confidence interval, 5 to 125). Proven pulmonary tuberculosis was diagnosed in 7 HIV-seropositive women (2.8%, 1.2 cases per 100 person-years) and 1 HIV-seronegative woman (0.3%, 0.12 cases per 100 person-years), for a relative risk of 10 (95% confidence interval, 1.5 to 47). We estimated that 66 cases of proven pulmonary tuberculosis in 100,000 person-years of follow-up in women of childbearing age could be attributed to HIV; this is 35% of their estimated total incidence of proven pulmonary tuberculosis. Among those followed for 2 yr, 27 (11%) of 243 HIV-seropositive women died during 2 yr of follow-up compared with none of 296 HIV-seronegative women (p less than 0.001). In HIV-seropositive women with proven or clinically diagnosed tuberculosis mortality was even higher: 5 (26%) of the 19 HIV-seropositive women with proven pulmonary or clinically diagnosed tuberculosis died during follow-up compared with 22 (10%) of the 224 HIV-seropositive women not diagnosed as having tuberculosis (relative risk 2.7; 95% confidence interval, 1.1 to 6.3).(ABSTRACT TRUNCATED AT 250 WORDS)     

The association of tuberculosis and HIV infection in Burundi

AIDS and tuberculosis (TB) are both endemic in Bujumbura, Burundi. An 11% failure rate to standard antituberculosis treatment (n = 173) was observed at the Tuberculosis Treatment Center of Bujumbura (CATB) in 1985-1986. All resistant cases (n = 19) were HIV seropositive. Among 328 consecutive cases with tuberculosis at the CATB during a 3 month period in 1986, 54.5% were HIV seropositive, which is five times higher than the prevalence in the general population in Bujumbura. More female patients than male cases were HIV antibody positive (62 versus 49%, respectively; p less than 0.02). Persistent weight loss, cough, and an anergic tuberculin test were more common in the HIV-seropositive group. Among 48 household members of HIV-seropositive patients with tuberculosis, 6 (12.5%) new cases of tuberculosis were identified, compared with none among 28 household members of HIV-seronegative patients with tuberculosis (odds ratio, 3.8; 95% confidence interval, 0.43-33.2). HIV infection is a new risk factor for tuberculosis in Africa, and HIV-infected cases of tuberculosis may be more infectious than HIV-negative patients. The AIDS epidemic may drastically complicate the diagnosis, management, and control of tuberculosis in populations in which both infections are endemic.     

Agreement between clinical scoring systems used for the diagnosis of pediatric tuberculosis in the HIV era.

BACKGROUND: Diagnosis of childhood tuberculosis (TB) remains a challenge, especially in high human immunodeficiency virus (HIV) prevalence areas. METHODS: Retrospective study of TB cases registered at a pediatric hospital over a 1-year period in Kinshasa, Democratic Republic of Congo. Data were used to calculate scores for eight diagnostic scoring systems. Correlations between scores, agreement among scoring systems on which children are in need of treatment, and clinical presentation by HIV infection status were assessed using Spearman rank correlations, kappa statistics and bivariate analysis. RESULTS: The 42 HIV-infected children were more likely to be older, exposed to TB, have a history of TB, and present with lymphadenopathy and malnutrition, compared to the 45 non-HIV-infected children. Correlations of scores between scales unrelated in their development and agreement among scales on decision to treat were moderate to poor. One in seven children would not have received treatment according to at least one scale. CONCLUSION: The clinical presentation of TB in HIV-infected and non-infected children was quite similar, but HIV-infected children were more likely to have a prior history of TB. Correlation between clinical scoring systems was poor, with some disagreement on the decision of whom to treat, underscoring the need for improved childhood TB diagnostics.     

Evaluation of a proposed diagnostic scoring system for pulmonary tuberculosis in Brazilian children.

In a case-control study to evaluate a systematic scoring system for diagnosing pulmonary tuberculosis (PTB) in children, cases had gastric lavage cultures positive for Mycobacterium tuberculosis and recovered after anti-tuberculosis treatment, while controls had negative cultures and recovered with non-anti-tuberculosis treatment. Radiological aspect (OR = 25.39), contact with a tuberculous adult (OR = 10.67) and tuberculin skin test > or = 10 mm (OR = 8.23) were associated with PTB diagnosis. The sensitivity of the score ranged from 58% to 89% and the specificity from 98% to 86%, with cut-offs of respectively > or = 40 or > or = 30. The scoring system may be a useful diagnostic method in areas with a high prevalence of TB.     

Manifestations and outcome of extra-pulmonary tuberculosis: impact of human immunodeficiency virus co-infection.

SETTING: Metropolitan New Orleans. OBJECTIVE: To determine the impact of human immunodeficiency virus (HIV) co-infection on the manifestations and outcome of extra-pulmonary tuberculosis (EPTB). DESIGN: Retrospective analysis of 136 patients diagnosed with EPTB between 1 January 1993 to 31 December 2001. Characteristics of EPTB were compared by HIV serostatus. RESULTS: Of those tested for HIV (n = 87), 42.5% were seropositive. Except for a higher frequency of disseminated TB among co-infected persons, the manifestations, laboratory diagnostic yield and outcome of EPTB were similar between HIV-infected and non-infected persons. The overall fatality rate was 20%; HIV-infected patients had a three-fold higher mortality compared to non-infected persons. In multivariate logistic regression analysis, factors associated with death were: HIV-seropositive (adjusted odds ratio [aOR] 5.2, 95% CI 1.1-24.65) compared to HIV-seronegative, disseminated and meningeal compared to lymphatic disease (aOR 16.87, 95% CI 12.31-123.34), and lack of TB treatment compared to receipt of TB treatment (aOR 29.23, 95% CI 14.47-191.23). CONCLUSION: Manifestations of EPTB were non-specific and did not differ between HIV-infected and non-infected persons. Severe disease, lack of TB treatment and HIV co-infection were associated withdeath. Approaches are needed to reduce EPTB morbidity and mortality, especially among HIV-infected persons.     

Low rates of child testing for HIV persist in a high-risk area of East Africa

Children in low- and middle-income countries (LMIC) are the least touched by recent successes in the diagnosis and treatment of HIV/AIDS globally. Early treatment is essential for a child's longer and higher quality of life; however, by 2011, only a small proportion of HIV-seropositive children in LMIC countries were receiving treatment, in part because of persisting low rates of diagnosis. This study of the prevalence and characteristics of children tested for HIV was embedded in the Coping with HIV/AIDS in Tanzania (CHAT) study in which HIV-seropositive and HIV-seronegative adults, and adults with unknown HIV status were asked about HIV testing for their children. Data were gathered from November 2009 to August 2010 during the scale-up of Prevention of Mother To Child Transmission and Early Infant Diagnosis programs in the region. Reports on 1776 children indicate that 31.7% of all children were reported to have been tested, including only 42.9% of children with an HIV-seropositive caregiver. In general, children more likely to be HIV tested were biological children of study participants, younger, of widowed adults, living in urban areas, and of HIV-seropositive parents/caregivers. Children belonging to the two indigenous tribes, Chagga and Pare, were more likely to be tested than those from other tribes. Rates of testing among children less than two years old were low, even for the HIV-seropositive caregiver group. The persistence of low testing rates is discussed in terms of the accessibility and acceptability of child testing in resource poor settings.     

Impact of human immunodeficiency virus type 1 on tuberculosis in rural Haiti

We conducted a case-control study to determine the relative and attributable risk of HIV seropositivity for bacillary-positive (smear and/or culture) pulmonary tuberculosis in Haiti. There were 274 patients with tuberculosis and an equal number of control subjects. Antibodies to HIV were present in 67 (24%) patients and eight (3%) control subjects. Odds ratios suggested that the risk of pulmonary tuberculosis was 15.7 times as great (95% confidence interval, 4.8 to 5.0; p less than 0.05) in patients 20 to 39 yr of age who were HIV-seropositive than in HIV-seronegative patients. In contrast, the relative risk in those 40 to 59 yr of age was elevated (3.0 times), though not significantly (lower 95% confidence interval, 0.8). In the 20- to 39-yr age group, 31% of tuberculosis was attributable to HIV infection (95% confidence interval between 23 and 39%). HIV-seropositive and HIV-seronegative patients did not differ with respect to sputum smear positivity. HIV-seronegative patients were twice as likely to be infected with resistant organisms, though this was not significant. We conclude that HIV infection is a major risk factor for pulmonary tuberculosis in young adult residents of Haiti. This, together with the fact that similar proportions of HIV-seropositive and HIV-seronegative patients were potentially infectious, suggests that without vigorous counteraction tuberculosis will become a greater problem for Haiti.     

Preferential recruitment of phagocytes into the lung of patients with advanced acquired immunodeficiency syndrome and tuberculosis

Limited data are available on the cellular and immunocytological characteristics of bronchoalveolar lavage (BAL) fluid in individuals infected with the human immunodeficiency virus (HIV) and pulmonary tuberculosis (TB). The immune host response against tuberculosis in early HIV-infection may differ from that in later stages of HIV disease, as is strongly suggested by different clinical and radiographic patterns. We studied the cellular elements in the lungs of 15 HIV-infected patients with advanced immunosuppression and pulmonary tuberculosis (TB/AIDS). The findings were compared with data from four other groups: 1) 15 HIV-seronegative patients with pulmonary TB; 2) 12 HIV-seropositive TB patients without previous AIDS-defining illnesses and with CD4+ >200 cells mm(-3); 3) five AIDS patients without pulmonary lesions; and 4) five healthy controls. BAL fluid and differential cell counts, as well as lymphocyte subsets, were determined. Despite a low CD4/CD8 ratio, the TB/AIDS group had a higher absolute number of CD8+ lymphocytes in the BAL fluid than the other groups. Alveolar macrophages and neutrophils were significantly increased in TB/AIDS patients compared to control groups. The number of eosinophils was increased in TB/HIV--patients but not in TB/AIDS patients. We conclude that tuberculosis in late stage HIV-infected patients has a distinct inflammatory cell profile, suggesting an enhanced compensatory mechanism that amplifies the unspecific inflammatory reaction.     

Comparison of sputum induction with fiberoptic bronchoscopy in the diagnosis of tuberculosis: experience at an acquired immune deficiency syndrome reference center in Rio de Janeiro, Brazil

Many patients with suspected pulmonary tuberculosis (PTB) do not produce sputum spontaneously or are smear-negative for acid-fast bacilli (AFB). We prospectively compared the yield of sputum induction (SI) and fiberoptic bronchoscopy with bronchoalveolar lavage (BAL) for the diagnosis of PTB in a region with a high prevalence of tuberculosis and human immunodeficiency virus (HIV) infection. Fifty seven percent (143 of 251) of patients had diagnoses of PTB, of whom 17% (25 of 143) were HIV seropositive. There were no significant differences in the yields of AFB smears or cultures whether obtained via SI or BAL. Among 207 HIV-seronegative patients, the AFB smear and mycobacterial culture results from specimens obtained by SI and BAL were in agreement in 97% (202 of 207) (kappa test = 0.92) and 90% (186 of 207) (kappa test = 0.78), respectively. Among HIV-seropositive patients the agreements between AFB smear and culture results for SI and BAL specimens were 98% (43 of 44) (kappa test = 0.93) and 86% (38 of 44) (kappa test = 0.69), respectively. We conclude that SI is a safe procedure with a high diagnostic yield and high agreement with the results of fiberoptic bronchoscopy for the diagnosis of PTB in both HIV-seronegative and HIV-seropositive patients.     

Diagnostic and management challenges for childhood tuberculosis in the era of HIV

The diagnosis and management of childhood tuberculosis (TB) pose substantial challenges in the era of the human immunodeficiency virus (HIV) epidemic. The highest TB incidences and HIV infection prevalences are recorded in sub-Saharan Africa, and, as a consequence, children in this region bear the greatest burden of TB/HIV infection. The tuberculin skin test (TST), which is the standard marker of Mycobacterium tuberculosis infection in immunocompetent children, has poor sensitivity when used in HIV-infected children. Novel T cell assays may offer higher sensitivity and specificity than the TST, but these tests still fail to make the crucial distinction between latent M. tuberculosis infection and active disease and are limited by cost considerations. Symptom-based diagnostic approaches are less helpful in HIV-infected children, because of the difficulty of differentiating TB-related symptoms from those caused by other HIV-associated conditions. Knowing the HIV infection status of all children with suspected TB is helpful because it improves clinical management. HIV-infected children are at increased risk of developing active disease after TB exposure/infection, which justifies the use of isoniazid preventive therapy once active TB has been excluded. The higher mortality and relapse rates noted among HIV-infected children with active TB who are receiving standard TB treatment highlight the need for further research to define optimal treatment regimens. HIV-infected children should also receive appropriate supportive care, including cotrimoxazole prophylaxis, and antiretroviral therapy, if indicated. Despite the difficulties experienced in resource-limited countries, the management of children with TB/HIV infection could be vastly improved by better implementation of readily available interventions.     

Relapse rates after short-course (6-month) treatment of tuberculosis in HIV-infected and uninfected persons.

OBJECTIVE: To determine the rate of tuberculosis relapse among HIV-seropositive and -seronegative persons treated for active tuberculosis with short-course (6-month) therapy. DESIGN: Consecutive cohort study. SETTING: City of Baltimore tuberculosis clinic. PATIENTS: Tuberculosis patients treated between 1 January 1993 and 31 December 1996. INTERVENTION: Patients received 2 months of isoniazid, rifampin, pyrazinamide and ethambutol followed by 4 months of isoniazid and rifampin. MAIN OUTCOME MEASURE: Passive follow-up for tuberculosis relapse was performed through September 30, 1998. RESULTS: There were 423 cases of tuberculosis during the study period; 280 patients completed a 6-month course of therapy. Therapy was directly-observed for 94% of patients. Of those who completed therapy, 47 (17%) were HIV-seropositive, 127 (45%) were HIV-seronegative, and 106 (38%) had unknown HIV status. HIV-infected patients required more time to complete therapy (median 225 versus 205 days; P = 0.04) but converted sputum culture to negative within the same time period (median 77 versus 72 days; P = 0.43) as HIV-seronegative or unknown patients. Relapse occurred in three out of 47 (6.4%) HIV-infected patients compared to seven out of 127 (5.5%) HIV-seronegative patients (P = 1.0). Relapse rates also did not differ when HIV-seropositive patients were compared with HIV-seronegative and patients with unknown HIV status (6.4% versus 3.0%; P = 0.38). Of the 10 patients with tuberculosis relapse, restriction fragment length polymorphism data were available for five; all five relapse isolates matched the initial isolate. CONCLUSIONS: These results support current recommendations to treat tuberculosis in HIV-infected patients with short-course (6-month) therapy.     

Tuberculosis incidence in developing countries with high prevalence of HIV infection.

OBJECTIVE: To study the impact of the HIV epidemic on tuberculosis (TB) incidence in developing countries. DESIGN: A simple mathematical model is constructed using figures from published reports to estimate the rise of TB incidence as the HIV epidemic expands. METHOD: Two groups with different risk of developing TB are identified: individuals with dual infection of HIV and Mycobacterium tuberculosis and the rest of the population. The model is based on a combination of the incidence and the percentage of TB in these two groups. The expected rise in TB incidence and the percentage of TB cases that will be HIV-positive are plotted against the prevalence of HIV. CONCLUSIONS: Unless appropriate action is taken, TB incidence in developing countries will double as the prevalence of HIV infection reaches 13 per hundred adults.     

Risk factors for negative sputum acid-fast bacilli smears in pulmonary tuberculosis: results from Dakar, Senegal, a city with low HIV seroprevalence.

SETTING: Two teaching hospitals in Dakar, Senegal, a West African country with a low prevalence of human immunodeficiency virus (HIV) infection. OBJECTIVE: To determine whether patients with HIV-associated pulmonary tuberculosis have fewer acid-fast bacilli (AFB) in their sputum as assessed by routine microscopy, and to correlate the findings with systematically obtained clinical, radiographic and laboratory variables. DESIGN: Prospective study from November 1995 to October 1996 of 450 consecutive patients diagnosed with pulmonary tuberculosis. RESULTS: Tuberculosis was diagnosed in 380 patients (84.4%) by positive bacteriology, in 61 (13.6%) by a favorable response to anti-tuberculosis chemotherapy, and in nine (2.0%) by the presence of a miliary radiographic pattern. Forty (8.9%) patients were HIV-seropositive. AFB-negative smears were found in 14/40 (35.0%) of the HIV-seropositive patients with pulmonary tuberculosis compared with 71/410 (17.3%) of the seronegative patients (risk ratio [RR] = 2.02, 95% confidence interval [CI] 1.26-3.24, P = 0.01). Multivariate analysis revealed that AFB smear negativity was associated with absence of cavitation (P = 0.002), lack of cough (P = 0.005), the presence of HIV seropositivity (P = 0.02), a CD4+ cell count above 200/mm3 (P = 0.02), and age over 40 years (P = 0.03). CONCLUSIONS: Compared with HIV-seronegative patients with pulmonary tuberculosis, seropositive patients in Dakar, Senegal, are more likely to have negative sputum-AFB smears. This phenomenon has now been observed in seven of eight sub-Saharan African countries with varying HIV seroprevalence from which reports are available.     

The impact of the HIV epidemic on tuberculosis control programmes in developing countries.

Worldwide, approximately 1.7 billion persons are infected with M. tuberculosis, and 5 million with HIV. In developing countries, a strong association exists between the 2 pathogens, with 14-30% of AIDS patients having tuberculosis (TB), and 12-60% of TB patients HIV-seropositive (HIV+). TB is one of the most frequent opportunistic infection in AIDS, and is a common way for AIDS to present. Evidence suggests that most TB cases in HIV+ patients are due to the endogenous reactivation of past TB infection instead of from new exogenous infection. Particular cause for concern exists in developing countries where approximately 1/2 of the population aged 20-40 years is infected with TB. While 10% of HIV-individuals may develop TB over their lifetimes, HIV+ individuals are at far greater risk of developing the disease. The paper discusses diagnosis, chemoprophylaxis, and treatment of TB. To help stymie major increases in TB patients as HIV spreads across populations with high prevalence of TB, the authors recommend offering HIV testing and counseling to all patients, including TB in the differential diagnoses of all pulmonary diseases in HIV+ patients, offering BCG vaccination to every nonsymptomatic AIDS newborn in countries with high levels of TB infection, routinely obtaining mycobacterial stains and cultures on specimens from HIV+ patients with respiratory symptoms, making clinicians aware of the many false negative tuberculin tests and atypical radiographic patterns in advanced HIV infection, offering 12 months of isoniazid chemoprophylaxis to those HIV+, treating HIV patients with TB with isoniazid, rifampicin, and 1 or 2 of pyrazinamide, ethambutol, or streptomycin during the 1st 2 months, and making health workers aware of infection risks from doing tuberculin tests and injecting streptomycin.