Prevalence of human immunodeficiency virus infection among patients attending tuberculosis clinics in the United States

Mycobacterium tuberculosis Primary Infection and Dissemination: A Critical Role for Alveolar Epithelial Cells

Globally, tuberculosis (TB) has reemerged as a major cause of morbidity and mortality, despite the use of the Mycobacterium bovis BCG vaccine and intensive attempts to improve upon BCG or develop new vaccines. Two lacunae in our understanding of the Mycobacterium tuberculosis (M. tb)-host pathogenesis have mitigated the vaccine efforts; the bacterial-host interaction that enables successful establishment of primary infection and the correlates of protection against TB. The vast majority of vaccine efforts are based on the premise that cell-mediated immunity (CMI) is the predominating mode of protection against TB. However, studies in animal models and in humans demonstrate that post-infection, a period of several weeks precedes the initiation of CMI during which the few inhaled bacteria replicate dramatically and disseminate systemically. The “Trojan Horse” mechanism, wherein M. tb is phagocytosed and transported across the alveolar barrier by infected alveolar macrophages has been long postulated as the sole, primary M. tb:host interaction. In the current review, we present evidence from our studies of transcriptional profiles of M. tb in sputum as it emerges from infectious patients where the bacteria are in a quiescent state, to its adaptations in alveolar epithelial cells where the bacteria transform to a highly replicative and invasive phenotype, to its maintenance of the invasive phenotype in whole blood to the downregulation of invasiveness upon infection of epithelial cells at an extrapulmonary site. Evidence for this alternative mode of infection and dissemination during primary infection is supported by in vivo, in vitro cell-based, and transcriptional studies from multiple investigators in recent years. The proposed alternative mechanism of primary infection and dissemination across the alveolar barrier parallels our understanding of infection and dissemination of other Gram-positive pathogens across their relevant mucosal barriers in that barrier-specific adhesins, toxins, and enzymes synergize to facilitate systemic establishment of infection prior to the emergence of CMI. Further exploration of this M. tb:non-phagocytic cell interaction can provide alternative approaches to vaccine design to prevent infection with M. tb and not only decrease clinical disease but also decrease the overwhelming reservoir of latent TB infection.

Transcriptional profiling of Mycobacterium tuberculosis replicating ex vivo in blood from HIV- and HIV+ subjects

Hematogenous dissemination of Mycobacterium tuberculosis (M. tb) occurs during both primary and reactivated tuberculosis (TB). Although hematogenous dissemination occurs in non-HIV TB patients, in ∼80% of these patients, TB manifests exclusively as pulmonary disease. In contrast, extrapulmonary, disseminated, and/or miliary TB is seen in 60–70% of HIV-infected TB patients, suggesting that hematogenous dissemination is likely more common in HIV+ patients. To understand M. tb adaptation to the blood environment during bacteremia, we have studied the transcriptome of M. tb replicating in human whole blood. To investigate if M. tb discriminates between the hematogenous environments of immunocompetent and immunodeficient individuals, we compared the M. tb transcriptional profiles during replication in blood from HIV- and HIV+ donors. Our results demonstrate that M. tb survives and replicates in blood from both HIV- and HIV+ donors and enhances its virulence/pathogenic potential in the hematogenous environment. The M. tb blood-specific transcriptome reflects suppression of dormancy, induction of cell-wall remodeling, alteration in mode of iron acquisition, potential evasion of immune surveillance, and enhanced expression of important virulence factors that drive active M. tb infection and dissemination. These changes are accentuated during bacterial replication in blood from HIV+ patients. Furthermore, the expression of ESAT-6, which participates in dissemination of M. tb from the lungs, is upregulated in M. tb growing in blood, especially during growth in blood from HIV+ patients. Preliminary experiments also demonstrate that ESAT-6 promotes HIV replication in U1 cells. These studies provide evidence, for the first time, that during bacteremia, M. tb can adapt to the blood environment by modifying its transcriptome in a manner indicative of an enhanced-virulence phenotype that favors active infection. Additionally, transcriptional modifications in HIV+ blood may further accentuate M. tb virulence and drive both M. tb and HIV infection.

Self-reported HIV testing practice among physicians treating tuberculosis in Australia and New Zealand

Not all people with tuberculosis have their HIV status ascertained despite the interaction between these infections. We investigated the self-reported HIV testing practice among physicians treating tuberculosis in Australia and New Zealand and used logistic regression to assess factors associated with a routine offer of HIV testing in cases of tuberculosis. Of 290 subjects, 61% always recommended an HIV test for a 38-year-old married man with smear-positive pulmonary tuberculosis. A lower proportion (40%) always tested a 78-year-old man or a female patient (58%), and more always HIV tested a South African case (85%), a patient with oral candidiasis (87%) or an unmarried male patient (66%). No scenario was associated with a universal offer of HIV testing. Clinician factors such as specialty (odds ratio [OR] 3.09), jurisdiction of practice (OR 4.09) and number of HIV tests requested in the past five years (OR 0.29) predicted the self-reported frequency of always HIV testing tuberculosis patients. At least 48% of respondents reported that epidemiological or clinical factors influenced their decision to offer testing. Strategies to increase HIV testing in cases of tuberculosis need to consider clinician factors.

Human immunodeficiency virus testing among patients with tuberculosis at a university hospital in Taiwan, 2000 to 2006

BACKGROUND/PURPOSE

Human immunodeficiency virus (HIV)-infected patients are more susceptible to tuberculosis (TB), which might be the initial presentation of HIV infection. This study assessed the frequency and results of HIV testing among patients diagnosed with TB at a university hospital from 2000 to 2006.

METHODS

Surveillance data for all reported TB cases from 2000 to 2006 were reviewed to identify patients with unknown HIV serostatus who received HIV testing when TB was diagnosed. Trends in HIV testing among TB patients were examined, and factors associated with HIV infection were analyzed.

RESULTS

From 2000 to 2006, 3643 patients were diagnosed with TB, and 49 with HIV infection prior to TB diagnosis were excluded. Of the 3594 patients with unknown HIV status before TB diagnosis, 1035 (28.8%) were offered HIV testing. There was an increasing trend of providing HIV testing to TB patients that ranged from 16.1% to 43.7% (p < 0.001), and the overall prevalence of HIV infection among TB patients was 5.6% (95% CI, 4.3-7.1%) of those tested. Compared with TB patients without HIV infection, those with HIV infection were more likely to be aged < 50 years [adjusted odds ratio (aOR), 8.0; 95% CI, 4.4-14.6), male (aOR, 7.1; 95% CI, 3.0-16.9), and present with extrapulmonary TB (aOR, 2.8; 95% CI, 1.7-4.6).

CONCLUSION

The frequency of HIV testing among TB patients remained low at the university hospital providing TB and HIV care in Taiwan from 2000 to 2006. Among those tested for HIV infection, age < 50 years, male gender and presentation of extrapulmonary TB were associated with HIV infection.

Extrapulmonary tuberculosis, human immunodeficiency virus, and foreign birth in North Carolina, 1993 - 2006

Background

The proportion of extrapulmonary tuberculosis (EPTB) reported in the United States has been gradually increasing. HIV infection and foreign birth are increasingly associated with tuberculosis and understanding their effect on the clinical presentation of tuberculosis is important.

Methods

Case-control study of 6,124 persons with tuberculosis reported to the North Carolina Division of Public health from January 1, 1993 to December 31, 2006. Multivariate logistic regression was used to obtain adjusted odds ratios measuring the associations of foreign birth region and US born race/ethnicity, by HIV status, with EPTB.

Results

Among all patients with tuberculosis, 1,366 (22.3%) had EPTB, 563 (9.2%) were HIV co-infected, and 1,299 (21.2%) were foreign born. Among HIV negative patients, EPTB was associated with being foreign born (adjusted ORs 1.36 to 5.09, depending on region of birth) and with being US born, Black/African American (OR 1.84; 95% CI 1.42, 2.39). Among HIV infected patients, EPTB was associated with being US born, Black/African American (OR 2.60; 95% CI 1.83, 3.71) and with foreign birth in the Americas (OR 5.12; 95% CI 2.84, 9.23).

Conclusion

Foreign born tuberculosis cases were more likely to have EPTB than US born tuberculosis cases, even in the absence of HIV infection. Increasing proportions of foreign born and HIV-attributable tuberculosis cases in the United States will likely result in a sustained burden of EPTB. Further research is needed to explore why the occurrence and type of EPTB differs by region of birth and whether host genetic and/or bacterial variation can explain these differences in EPTB.

Bacterial pericarditis: diagnosis and management

Bacterial pericarditis occurs by direct infection during trauma, thoracic surgery, or catheter drainage, by spread from an intrathoracic, myocardial, or subdiaphragmatic focus, and by hematogenous dissemination. The frequent causes are Staphylococcus and Streptococcus (rheumatic pancarditis), Haemophilus, and M. tuberculosis. In AIDS pericarditis, the incidence of bacterial infection is much higher than in the general population, with a high proportion of Mycobacterium avium-intracellulare infection. Purulent pericarditis is the most serious manifestation of bacterial pericarditis, characterized by gross pus in the pericardium or microscopically purulent effusion. It is an acute, fulminant illness with fever in virtually all patients. Chest pain is uncommon. Purulent pericarditis is always fatal if untreated. The mortality rate in treated patients is 40%, and death is mostly due to cardiac tamponade, systemic toxicity, cardiac decompensation, and constriction. Tuberculous infection may present as acute pericarditis, cardiac tamponade, silent (often large) relapsing pericardial effusion, effusive-constrictive pericarditis, toxic symptoms with persistent fever, and acute, subacute, or chronic constriction. The mortality in untreated patients approaches 85%. Urgent pericardial drainage, combined with intravenous antibacterial therapy (e.g. vancomycin 1g twice daily, ceftriaxone 1-2g twice daily, and ciprofloxacin 400 mg/day) is mandatory in purulent pericarditis. Irrigation with urokinase or streptokinase, using large catheters, may liquify the purulent exudate, but open surgical drainage is preferable. The initial treatment of tuberculous pericarditis should include isoniazid 300 mg/day, rifampin 600 mg/day, pyrazinamide 15-30 mg/kg/day, and ethambutol 15-25 mg/kg/day. Prednisone 1-2 mg/kg/day is given for 5-7 days and progressively reduced to discontinuation in 6-8 weeks. Drug sensitivity testing is essential. Pericardiectomy is reserved for recurrent effusions or continued elevation of central venous pressure after 4-6 weeks of antituberculous and corticosteroid therapy.

Survey of human immunodeficiency virus (HIV)-seropositive patients with mycobacterial infection in Japan

OBJECTIVE

To assess DNA polymorphisms in mycobacterial isolates obtained from human immunodeficiency virus (HIV)-seropositive patients with tuberculosis in Japan from 1996 to 2003.

METHODS

Restriction fragment length polymorphisms (RFLP) from Mycobacterium tuberculosis and Mycobacterium avium isolates obtained from individual seropositive patients with tuberculosis (n=78) were analysed with the use of IS6110 and (CGG)(5) or IS1245 and IS1311, respectively, as markers. As a control, the same procedures were applied to isolates from HIV-seronegative tuberculosis patients (n=87).

RESULTS

Of 86 mycobacterial strains, M. tuberculosis, M. avium and Mycobacterium chelonae were identified in 48 (55.8%), 36 (41.9%) and 2 (2.3%) isolates, respectively. The obtained RFLP patterns of M. tuberculosis isolates from both the HIV-seropositive and -seronegative groups were variable, suggesting no obvious clustering among the isolates. Similar results were obtained in isolates of M. avium.

CONCLUSIONS

This is the first report on the molecular epidemiology of Mycobacterium spp. isolated from HIV-seropositive patients in Japan. The results indicate that no particular clones of M. tuberculosis or M. avium prevail in HIV-seropositive patients in Japan. Further monitoring of mycobacterial infection associated with HIV infection in Japan should be continued.

Imaging of musculoskeletal and spinal tuberculosis

The diagnosis of tuberculosis of the musculoskeletal system is difficult for many reasons. As Walker states, to diagnose tuberculosis one must consider the possibility. The uncommonness of osteoarticular MTb results in clinician inexperience, which leads to overlooking the diagnosis. Subtle early manifestations may elude detection. Negative skin tests and normal chest films do not exclude the consideration of tuberculosis. The most conclusive means of reaching the diagnosis (biopsy and culture) necessitate invasive procedures that are not always definitive, and may require repeated attempts. Management and surgical decisions, however, rely on prompt diagnosis; diagnostic delay has prognostic implications and results in significant morbidity. Musculoskeletal tuberculosis produces no pathognomonic imaging signs, and in advanced stages mimics other disease processes. Despite these difficulties, the diagnostician's goal is to catch the disease as early as possible, because antibiotic treatment can lead to resolution and obviate more radical management. The radiologist must be aware of the groups at greatest risk, and typical and atypical presentations at imaging. The eventual eradication of MTb is conceivable, although not presently within our grasp. Maintaining reasonable suspicion and developing cognizance of the patterns of presentation allow the radiologist to diagnose efficiently the patient who presents with osteoarticular tuberculosis.

Effective detection of HIV

Biomedical advances, new HIV testing technologies, and policy shifts in the last 15 years have created substantial new challenges and opportunities for service providers, policy makers, and researchers regarding broad scale identification of HIV-seropositive persons. Effective HIV testing will be achieved when we: (1) increase the number of high-risk persons tested; (2) decrease the time from HIV infection to detection; (3) increase testing acceptability; (4) increase the proportion of individuals tested who receive their results; and (5) increase the proportion of individuals tested seropositive who are linked to care. Strategies to enhance effectiveness include implementing new testing technologies and delivery modalities; expanding access to client-controlled testing; targeting providers' knowledge, attitudes, and behaviors regarding HIV testing; mainstreaming HIV testing as routine clinical care; targeting persons who engage in high-risk behaviors and those in high-risk groups; and implementing a national behavioral surveillance system. Addressing these challenges will improve HIV detection in the United States, which is vital to both HIV prevention and treatment.

Antimycobacterial activities of novel levofloxacin analogues

In order to investigate structure-activity relationships between antimycobacterial activities and basic substituents at the C-10 position of levofloxacin (LVFX), we synthesized a series of pyridobenzoxazine derivatives by replacement of the N-methylpiperazinyl group of LVFX with various basic substituents. A compound with a 3-aminopyrrolidinyl group had one-half the activity of LVFX against Mycobacterium avium, M. intracellulare, and M. tuberculosis. Mono- and dimethylation of the 3-amino moiety of the pyrrolidinyl group increased the activities against M. avium and M. intracellulare but not those against M. tuberculosis. On the other hand, dialkylation at the C-4 position of the 3-aminopyrrolidinyl group enhanced the activities against M. avium, M. intracellulare, and M. tuberculosis. Thus, introduction of an N-alkyl or a C-alkyl group(s) into the 3-aminopyrrolidinyl group may contribute to an increase in potency against M. avium, M. intracellulare, and/or M. tuberculosis, probably through elevation of the lipophilicity. However, among the compounds synthesized, compound VII, which was a 2,8-diazabicyclo[4.3.0]nonanyl derivative with relatively low lipophilicity, showed the most potent activity against mycobacterial species: the activity was 4- to 32-fold more potent than that of LVFX and two to four times as potent as that of gatifloxacin. These results suggested that an increase in the lipophilicity of LVFX analogues in part contributed to enhancement of antimycobacterial activities but that lipophilicity of the compound was not a critical factor affecting the potency.

Prevalência da infecção pelo HIV em pacientes internados por tuberculose

Objetivos: Verificar a prevalência da co-infecção tuberculose (TBC)/HIV e a capacidade da anamnese em detectar a infecção pelo HIV em pacientes internados por TBC. Local: Hospital Eduardo de Menezes, Belo Horizonte, MG, referência para TBC e SIDA. Material e métodos: Todos os pacientes internados com TBC na enfermaria de pneumologia foram avaliados prospectivamente no período de 1/1/1997 até 31/1/1998, com anamnese dirigida para fatores de risco para SIDA, TBC, tratamentos anteriores e abandonos de tratamento para TBC, e verificadas as formas clínicas de TBC. Foram excluídos pacientes com doenças marcadoras de SIDA com exceção da TBC, ou com sorologia anti-HIV realizada anteriormente. Foram realizadas sorologias anti-HIV (ELISA) e, quando positivas, confirmadas pelo teste Western-Blot. Os testes do qui-quadrado e de Fisher foram usados para análise estatística. Resultados: Sessenta e cinco pacientes avaliados foram divididos em grupo I (sorologia positiva para HIV, n = 6) e grupo II (sorologia negativa para HIV, n = 59). Não houve diferença significativa entre os dois grupos quanto a fatores de risco para SIDA, TBC, abandonos de tratamento ou tratamentos anteriores para TBC ou formas clínicas de TBC. Conclusões: Devido à alta prevalência da infecção pelo HIV (9,2%) no grupo estudado, estes achados reforçam as orientações do Consenso Brasileiro de Tuberculose no sentido de: 1) a anamnese não consegue detectar uma parcela significativa dos pacientes com co-infecção TBC/HIV; e: 2) a solicitação de sorologia anti-HIV deve ser feita de forma rotineira em todos os pacientes com TBC ativa.

Tuberculosis in human immunodeficiency virus-infected and human immunodeficiency virus-exposed children in New York City. The New York City Pediatric Spectrum of HIV Disease Consortium

BACKGROUND

Tuberculosis disease incidence increased sharply in New York City (NYC) in the late 1980s in children and adults. The relationship of tuberculosis disease in adults with the coincident epidemic of immunosuppression caused by HIV disease has been well-documented. This paper examines the relationship of tuberculosis and HIV in children in NYC.

METHODS

Information on tuberculosis was collected by retrospective chart abstraction in a cohort of HIV-exposed and infected children enrolled in a longitudinal study of HIV. Tuberculosis cases were ascertained by chart review or by matching HIV-infected and -exposed children to NYC Tuberculosis Registry cases. NYC Tuberculosis Registry data on children reported from 1989 to 1995, and not reported as HIV-infected, were used for comparison.

RESULTS

Tuberculosis disease was found in 45 (3%) of 1426 HIV-infected children (0.61 per 100 child years of observation) and in 5 (0.5%) of 1085 HIV-exposed uninfected children (0.2 per 100 child years). 30% of children were evaluated for HIV only after presenting with tuberculosis. Children with tuberculosis and HIV were more likely than other age-matched HIV-infected children to have decreased CD4+ T lymphocyte counts (66% vs. 37%, P = 0.02) and more likely than other NYC children with tuberculosis to have culture-confirmed and extrapulmonary tuberculosis. In this series 8 of 21 deaths in HIV-infected children with tuberculosis appeared to be related to tuberculosis.

CONCLUSIONS

During a period of high tuberculosis incidence in NYC, 3% of HIV-infected children in our cohort had tuberculosis, higher than the rate in uninfected children born to HIV-positive mothers in the same cohort. Because of this association, HIV-infected children with pulmonary illness should be tested for tuberculosis; and all children with tuberculosis should be tested for HIV.

Role of CD4:CD8 ratio in predicting HIV co-infection in patients with newly diagnosed tuberculosis

Because of the clinical implications of Human Immunodeficiency Virus (HIV) status on treatment of tuberculosis (TB) and in view of the low percentage of patients in whom HIV testing is performed, we evaluated immunological features of 54 patients with newly diagnosed TB and its ability to predict HIV co-infection. All 54 patients had initially unknown HIV status and had no other Acquired Immunodeficiency Syndrome (AIDS) defining illnesses. Twenty-two patients were found to be HIV seropositive and 32 were seronegative. The median CD4 and CD8 counts were statistically different between the HIV seropositive and seronegative patients, however, there was overlap between the two groups. The median CD4:CD8 ratio was 0.17 in HIV seropositive patients and 1.95 in the seronegative patients and had minimal overlap (p < 0.0001). A CD4:CD8 ratio < or = 0.7 gave a sensitivity of 100%, specificity of 94%, positive-predictive value of 92% and a negative-predictive value of 100% in predicting HIV co-infection. In conclusion, HIV-co-infection in patients with newly diagnosed TB could be predicted on the basis of the CD4:CD8 ratio.

Universal HIV screening at a major metropolitan TB clinic: HIV prevalence and high-risk behaviors among TB patients

OBJECTIVES

This study assessed the outcome of implementing a policy of universal screening of patients with tuberculosis (TB) for HIV infection at a major metropolitan public health TB clinic.

METHODS

HIV serologic testing was completed on 768 (93%) of 825 eligible patients. Ninety-eight HIV-positive cases (13%) were compared with 670 HIV-negative cases. The presence of adult HIV risk factors was determined by structured interview and review of medical records.

RESULTS

One or more HIV risk factors were present in 93% of HIV-positive cases and 42% of HIV-negative cases.

CONCLUSIONS

The metropolitan TB clinic is well suited for HIV screening, and HIV-antibody testing and counseling should be provided to all TB patients.

The ethnic minority traveler

Although the ethnic minority traveler is exposed to the same risks as other travelers, there are special considerations that make them vulnerable to certain diseases. In addition, many ethnic minority travelers are traditionally underserved by the medical community and often travel without the benefit of adequate counseling and immunization. The specific disease entities covered in this article include parasitic diseases (e.g. malaria, trypanosomiasis, intestinal helminths), tuberculosis, and other respiratory diseases, dengue, and sexually transmitted diseases and HIV.

HIV prevalence and risk behaviors among patients attending Los Angeles County Tuberculosis Clinics: 1993-1996

PURPOSE

This study aimed to describe prevalence of and risk factors for HIV among persons with newly diagnosed class III (confirmed) and class V (suspected) cases of tuberculosis (TB) patients in Los Angeles County.

METHODS

HIV testing was performed on 1307 blood specimens after routine tests were completed at six TB clinics in Los Angeles County. HIV test results were matched to demographic and risk behavior information by use of an unlinked study methodology.

RESULTS

The overall HIV prevalence rate was 10.8%. By demographic characteristics, the highest prevalence rates were observed among persons born in the United States (15.7%), males (14.1%), blacks (14.3%), and those aged 30-44 years (14.4%). Confirmed TB cases (14%) were more likely to be HIV-infected than were suspect cases (9.6%). Risk behaviors associated with positive HIV serostatus included the injection of nonprescription drugs, having sex with an injection drug user, and use of noninjection forms of heroin, cocaine, and tranquilizers. Men who have sex with men were more likely to be HIV-infected than were heterosexual males.

CONCLUSIONS

HIV testing and counseling should be a standard of care in TB clinics. The observed high HIV prevalence rate reinforces the importance of designing prevention strategies that specifically target patients with TB.

Co-occurrence of AIDS and tuberculosis: results of a database "match" and investigation

PURPOSE

To conduct a match between the AIDS and Tuberculosis (TB) Registries in Philadelphia.

METHODS

Database extracts for the year 1993 were prepared manually and matched by name, birth date, and social security number. Reported cases not matching with those on the primary registry were investigated. Proportion levels of comorbidity were calculated. Predictors of comorbidity were evaluated separately for the TB sample and for the AIDS sample.

RESULTS

The proportion of comorbid patients with AIDS alive at midyear was 4.7%; 17.1% of TB cases were also HIV-positive. Twenty-three percent of AIDS cases were falsely reported as having active TB; the false-positive rate in TB Control for HIV seropositivity was 4.2%. Having public or no health insurance, injection drug use (IDU) or heterosexual risk background (HET), and being nonwhite and female were significant predictors of active TB in persons with AIDS.

CONCLUSIONS

A registries' data match can provide useful information and result in improved validity for both registries. Although women with AIDS initially appeared to have a higher risk of having active TB, additional parallel analyses suggested that this effect was primarily the result of the 1993 expansion of the definition of AIDS.

Modeling the impact of HIV on the spread of tuberculosis in the United States

Tuberculosis (TB) was thought to be safely in decline in the United States in the mid-1980s because the number of cases had dropped by 74% between 1953 and 1985. An increase in TB cases was reported, however, in 1986, and an upward trend in TB incidence has continued. The turnaround in TB is well correlated with the rise of the HIV (human immunodeficiency virus) epidemic. The purpose of this work is to investigate, through the use of mathematical models, the magnitude and duration of the effect that the HIV epidemic may have on TB. Models are developed which reflect the transmission dynamics of both TB and HIV, and the relative merits of these models are discussed. The models are then linked together to form a model for the combined spread of both diseases. A numerical study is performed to investigate the influence of certain key parameters. The effect that HIV will have on the general population is found to be dependent on the contact structure between the general population and the HIV risk groups, as well as a possible shift in the dynamics associated with TB transmission.

[HIV/tuberculosis co-infection: a request for a better surveillance]

The increasing endemicity of tuberculosis resulting from causes such as immigration, poverty, a declining public health infrastructure and co-infection by HIV/Mycobacterium tuberculosis, is leading to a change in tuberculosis control programmes. One of the main reasons for the resurgence of tuberculosis is HIV infection--the risk of tuberculosis is greater in HIV patients than in the majority of the population as can be seen from numerous research projects. The need for systematic testing for HIV infection in all tuberculosis patients by undertaking confidential HIV tests on admission to a tuberculosis programme is brought out. This measure would increase the number of cases diagnosed and provide data for better surveillance of the co-infection.

Tuberculosis. Part I

Tuberculosis has been a disease of human beings for thousands of years. In recent times it has waxed to become the feared White Plague of the eighteenth and nineteenth centuries and waned under the impact of effective chemotherapy until its elimination seemed possible by the early twenty-first century. The resurgence of tuberculosis in the past 10 to 15 years, caused by unanticipated events such as the appearance of the human immunodeficiency virus and deteriorating social conditions, also brought with it the problem of multiple drug resistance. Control measures such as tuberculin skin testing, perhaps somewhat forgotten when tuberculosis seemed to be a disease of the past, again became first-line defenses against spread of the disease. Environmental controls must be well understood and used effectively. Diagnosis of tuberculosis requires knowledge of the strengths and shortcomings of the various diagnostic methods and experience in their use. Practitioners are cautioned to remember that no diagnostic method, by itself, can be relied on to confirm or rule out tuberculosis. Well-tested diagnostic methods of chest radiograph, tuberculin skin testing, smear, and culture have been recently supplemented by rapid diagnostic tests based on amplification of bacterial RNA and DNA. More invasive diagnostic methods are sometimes required to diagnose extrapulmonary disease. Two-drug up to seven-drug therapy may be indicated for a case of tuberculosis, depending on evidence of the presence of multiple drug resistance. Duration of treatment can range from 6 to 12 months, also depending on identification of drug-sensitive or drug-resistant organisms. Failure of compliance can be a significant problem in patients who are homeless, or drug abusers, or who for various reasons cannot or will not complete a course of therapy. Directly observed therapy is strongly recommended for these patients, and for assistance in its administration the physician must cooperate with the local or state health department. The health department also must be notified whenever a case of tuberculosis is identified.

The epidemiology of tuberculosis in the United States

After a dramatic increase in the incidence of TB in the United States from 1985 to 1992, the epidemiology of TB changed, with both the number of cases and the incidence of TB decreasing since 1992. The decreases have been focal, however, affecting only certain geographic areas (e.g., New York, California, and New Jersey) and certain populations (e.g., 25-44 year age group and people born in the United States). The factors responsible for the decrease in those areas and populations are multiple but the most important are thought to be improvements in TB control and treatment programs in communities serving populations at greatest risk for TB. Despite the overall decline in TB cases, the numbers of foreign-born people with TB continue to increase. Factors contributing to the increase in TB among foreign-born people include the prevalence of TB in the country of origin, duration of residence in the United States after immigration, inadequate screening for or treatment of TB before entering the United States, and inadequate follow-up of those who have entered the United States with noninfectious TB (i.e., abnormal chest radiograph with negative sputum smears). Control of TB among the foreign-born population is essential if the current downward trend in reported TB cases in the United States is to be maintained. The HIV epidemic had a significant impact on the increase in TB incidence in the United States in the late 1980s but improvements in measures to control transmission of TB appear to have been effective in reversing that trend. The current national decrease trend in TB morbidity can be sustained through organized efforts by federal and private agencies and state and local health departments to ensure that all people with TB are identified and treated promptly. Such efforts must be aimed at areas and populations identified as high risk for TB, especially foreign-born people and people who are infected with HIV.

Tuberculosis and human immunodeficiency virus infection

Mycobacterium tuberculosis infects one third of the world's population, and tuberculosis remains one of the most common infectious diseases of humans. From a global perspective, tuberculosis may be one of the most common HIV-related opportunistic infections. HIV immunosuppression has had a dramatic influence on the epidemiology, natural history and clinical presentation of tuberculosis. Treatment is highly effective for drug susceptible tuberculosis and has been shown to have a significant impact on resistant, especially multidrug-resistant, tuberculosis if started promptly. Directly observed therapy and rigorous adherence to infection control principles have helped control the tuberculosis epidemic in the United States.

Impact of human immunodeficiency virus infection on abdominal tuberculosis in western India

We studied the seroprevalence of human immunodeficiency virus infection in patients with pulmonary tuberculosis and abdominal tuberculosis. We also assessed the clinical characteristics, risk factors, tuberculin status, site, and response to therapy of abdominal tuberculosis in human immunodeficiency virus (HIV)-seropositive and HIV-seronegative patients. Volunteer blood donors (n = 8,395), patients with pulmonary tuberculosis (n = 387), and patients with abdominal tuberculosis (n = 108) were screened for HIV 1 and/or HIV 2 by enzyme-linked immunosorbent assay (ELISA; Torrent, India) and positivity reconfirmed by a repeat ELISA and Western blot test. The HIV seroprevalence in the abdominal tuberculosis patients (16.6%) was significantly higher compared with those with pulmonary tuberculosis (6.9%, p < 0.05) and volunteer blood donors (1.4%, p < 0.01). Absolute lymphocyte counts did not differ between the HIV-seropositive and HIV-seronegative patients (2,044.94 +/- 830 vs 2,261.34 +/- 805/mm3, p = NS). The Mantoux reaction was larger in the HIV-seronegative group as compared with the HIV-seropositive group (14.8 mm vs. 9.5 mm, p < 0.05). Tuberculosis patients responded well to conventional antituberculosis drugs in standard doses regardless of their HIV status.

Mycobacterial complications of HIV infection

Tuberculosis is the most common opportunistic infection worldwide and is caused by the only readily transmissible pathogen among persons with HIV infection. If treatment is initiated promptly and is supervised appropriately, cure, fortunately, is highly likely. Isoniazid preventive therapy substantially reduces the risk of tuberculosis in persons with HIV infection. Of the nontuberculous mycobacteria, Mycobacterium avium complex (MAC) is the most frequent cause of disease; however, disseminated MAC disease usually is not seen until the CD4+ cell count is less than 50 cells/L. Newer agents, such as the macrolides and rifabutin, form the nucleus of treatment regimens and also are effective in preventing the disease.

Hospitalization of patients infected with active TB in New York State, 1987-1992: the effect of the HIV epidemic

Hospital discharge records were used to study the relationship between human immunodeficiency virus (HIV) epidemic and hospitalized patients with tuberculosis in New York State from 1987 through 1992. The discharges of patients coinfected with HIV and tuberculosis increased by 270%, rising from 1,573 in 1987 to 5,825 in 1992. This constitutes an increase from 19.8 to 49.1% of all discharges of patients with tuberculosis. Discharges of tuberculosis patients who were not infected with HIV decreased slightly during this time, going from 6,359 to 6,039. Postdischarge treatment plans, HIV prevention, HIV testing, and HIV educational programs for the tuberculosis population require special consideration, given the significant rise of HIV in the tuberculosis-infected population.

Structure-activity relationships of the quinolone antibacterials against mycobacteria: effect of structural changes at N-1 and C-7

The re-emergence of tuberculosis infections which are resistant to conventional drug therapy has demonstrated the need for alternative chemotherapy against Mycobacterium tuberculosis. As part of a study to optimize the quinolone antibacterials against M. tuberculosis, we have prepared a series of N-1- and C-7-substituted quinolones to examine specific structure-activity relationships between modifications of the quinolone at these two positions and activity against mycobacteria. The compounds, synthesized by literature procedures, were evaluated for activity against Mycobacterium fortuitum and Mycobacterium smegmatis as well as Gram-negative and Gram-positive bacteria. The activity of the compounds against M. fortuitum was used as a barometer of M. tuberculosis activity. The results demonstrate that (i) the activity against mycobacteria was related more to antibacterial activity than to changes in the lipophilicity of the compounds, (ii) the antimycobacterial activity imparted by the N-1 substituent was in the order tert-butyl > or = cyclopropyl > 2,4-difluorophenyl > ethyl approximately cyclobutyl > isopropyl, and (iii) substitution with either piperazine or pyrrolidine heterocycles at C-7 afforded similar activity against mycobacteria.

Drug resistance patterns among tuberculosis patients in Rome, 1990-1992

Prevalence of, and risk factors for, drug-resistance of Mycobacterium tuberculosis were assessed among 407 hospitalized patients with tuberculosis in Rome, Italy, during the period 1990-1992. Resistance to 1 or more drugs was detected in 106 isolates (26%). Resistance to streptomycin was the most common (18.4%), followed by isoniazid (10.3%) and rifampin (7.9%). 23 isolates (5.7%) were resistant to both isoniazid and rifampin. Resistance to at least 1 drug and resistance to both isoniazid and rifampin were significantly more common among recurrent cases (40.7% vs. 22.1%, p < 0.001; and 22.1% vs. 1.2%, p < 0.001). Sex, country of origin and HIV infection were not significantly associated with prevalence of drug resistance. Among recurrent cases, prevalence of resistance to at least 1 drug and of resistance to both isoniazid and rifampin, was higher in subjects who had had a previous episode of tuberculosis later than 1969. In the population studied the prevalence of drug-resistant tuberculosis was high, although the risk of initially becoming infected with a multidrug-resistant strain of M. tuberculosis in this area appears to be low. This study suggests the need for enhanced surveillance of drug-resistance of tuberculosis in our country and for implementation of intervention aimed to ensure adequate and complete therapy for patients with tuberculosis.

Predictive markers of survival in HIV-seropositive and HIV-seronegative Tanzanian patients with extrapulmonary tuberculosis

SETTING

Prediction of survival in Tanzanian patients with extrapulmonary tuberculosis (TB).

OBJECTIVE

To evaluate the prognostic value of clinical and laboratory parameters on survival in human immunodeficiency virus (HIV) seropositive and HIV seronegative patients with extrapulmonary TB.

DESIGN

Over an 8-month period 192 consecutive patients with extrapulmonary TB, admitted to a major referral centre in Tanzania, were enrolled in the study. Their symptoms, signs and PPD skin test were noted. Their sera were tested for HIV and analyzed for beta-2-microglobulin content. Univariate risk factors for 12 months' survival after the start of anti-TB chemotherapy were entered into a stepwise Cox regression model. Survival probabilities were estimated according to the number of risk factors.

RESULTS

Of the 192 patients 126 (65%) were HIV-infected, and 29.7% had disseminated TB. Thirty-five patients, of whom 24 (68.6%) were HIV-positive, withdrew from the study immediately after hospital discharge. For survival analysis 157 patients remained. Within 12 months' follow-up after initiation of anti-TB therapy, the case fatality rate of the 102HHIV-infected patients was 22% and of the 55 HIV seronegative patients 2% (P < 0.001). In the HIV seropositive patients the following independent risk factors were significantly associated with a decreased probability of survival: peripheral lymphadenopathy (Hazard Rate Ratio (HRR) 5.2, 95% Confidence Interval [CI] 1. 7-16.2), a decreased activity score (bedridden > 50%/day (HRR 4.5, 95% CI 1.7-11.7), lymphopenia of < 1000/microL (HRR 4.4, 95% CI 1.7-11.8), and mycobacteraemia (HRR 4.0, 95% CI 1.2-13-.1). An anergic PPD skin test reaction proved to be another independent risk factor when the analysis was performed on 89 patients with available Mantoux test results. In the HIV seropositive patients, the 12 months' survival probabilities were 93%, 86%, 54% and 0% for presence of 0, 1, 2, and > 2 risk factors respectively.

CONCLUSION

Estimation of survival probabilities in patients with extrapulmonary TB may be possible without performing CD4 cell counts.

DNA fingerprinting and phenotyping of Mycobacterium tuberculosis isolates from human immunodeficiency virus (HIV)-seropositive and HIV-seronegative patients in Tanzania

With the purpose of determining whether the risk of infection with a particular clone of Mycobacterium tuberculosis is influenced by the human immunodeficiency virus (HIV) status of the host, we analyzed and compared 68 mycobacterial isolates obtained from HIV-seropositive patients with tuberculosis (TB) in Dar es Salaam, Tanzania, with 66 mycobacterial isolates obtained from HIV-seronegative patients with TB in the same geographical region by using both DNA fingerprinting and classical phenotyping methods. One hundred one different IS6110 fingerprinting patterns were observed in the 134 isolates. The level of diversity of the DNA fingerprints observed in the HIV-seropositive group was comparable to the level of the diversity observed in the HIV-seronegative group. Resistance to a single anti-TB drug was found in 8.8% of the tested isolates, and 3.2% of the isolates were resistant to more than one anti-TB drug. The drug susceptibility profiles were not significantly difference between the two groups of isolates compared in the present study. Phenotypic characteristics which classify M. tuberculosis strains as belonging to the Asian subgroup correlated with a low IS6110 copy number per isolate. However, the occurrence of Asian subgroup strains was not associated with the HIV status of the patients. The results of the study suggested an equal risk of infection with a defined M. tuberculosis clone for HIV-seropositive and HIV-seronegative individuals.

The epidemiology of tuberculosis among foreign-born persons in the United States, 1986 to 1993

BACKGROUND

One third of the world's population is infected with Mycobacterium tuberculosis, and in the developed countries immigration is a major force that sustains the incidence of tuberculosis. We studied the effects of immigration on the epidemiology of tuberculosis and its recent resurgence in the United States.

METHODS

We analyzed data from the national tuberculosis reporting system of the Centers for Disease Control and Prevention. Since 1986 reports of tuberculosis have included the patient's country of origin. Population estimates for foreign-born persons were derived from special samples from the 1980 and 1990 censuses.

RESULTS

The proportion of persons reported to have tuberculosis who were foreign-born increased from 21.6 percent (4925 cases) in 1986 to 29.6 percent (7346 cases) in 1993. For the entire eight-year period, most foreign-born patients with tuberculosis were from Latin America (43.9 percent; 21,115 cases) and Southeast Asia (34.6 percent; 16,643 cases). Among foreign-born persons the incidence rate was almost quadruple the rate for native residents of the United States (30.6 vs. 8.1 per 100,000 person-years), and 55 percent of immigrants with tuberculosis had the condition diagnosed in their first five years in the United States.

CONCLUSIONS

Immigration has had an increasingly important effect on the epidemiology of tuberculosis in the United States. It will be difficult to eliminate tuberculosis without better efforts to prevent and control it among immigrants and greater efforts to control it in the countries from which they come.

HIV infection and tuberculosis: an epidemiological study from a French register

SETTING

The possible impact of the human immunodeficiency virus (HIV) infection on the epidemiology of tuberculosis has never been studied in a general French population.

OBJECTIVE

To describe the evolution of tuberculosis incidence from 1983 to 1991 in a French district (Rhône) and to assess its relationships to HIV-related factors, and to determine the prevalence of HIV infection among adult tuberculosis patients registered from 1989 to 1991.

DESIGN

Information on sex, age, country of birth and the history and site of tuberculosis was derived from notification forms, and information on HIV testing was collected especially for this study.

RESULTS

During these nine years, 2916 tuberculosis cases were registered. The incidence increased in 1991 after a slow decline in previous years. An analysis of the evolution in the distribution of cases did not suggest any effect of HIV infection on the epidemiology of tuberculosis, with the exception of an increase in the proportion of patients originating from the Antilles and sub-Saharan Africa. The conservative estimate of prevalence of HIV infection was 9.8% in young adult patients.

CONCLUSION

The overlap between the population with HIV infection and that with tuberculosis seems to be small and restricted to particularly vulnerable sub-groups of the population of this region.

Tuberculosis in the Republic of Cuba: its possible elimination

SETTING

Tuberculosis elimination is a priority in most developed countries, although the AIDS epidemic and drug resistance are a handicap in some of them. Tuberculosis is an even greater problem in developing countries.

OBJECTIVE

To evaluate the epidemiological situation in Cuba, the trend of new cases reported for 1979-91 by clinical category and age group is described.

DESIGN

A simple regression model was fitted to the time series data on 'new case' rates taken from the national surveillance system. The annual variation percentage was estimated.

RESULTS

From 1979-91 tuberculosis decreased by 59.5% (from 11.6-4.7 per 10(5) persons per year). This decline occurred in all age groups; 60% of new cases in 1991 were aged 45 years and over, of which 30% were aged 65 and over. Drug resistance of Mycobacterium tuberculosis strains (2.49% in 1989) remains uncommon and HIV infection (0.009% in 1991) is rare in the general population.

CONCLUSIONS

The continuing steady decline of the number of new cases reported, in addition to the favorable trend of drug resistance and the low rate of HIV infection in the general population so far seem to indicate the real possibility of maintaining the effectiveness of the National Programme for Tuberculosis Control in the future, making it reasonable to formulate new strategies for the elimination of the disease.

The association of tuberculosis and HIV infection in Harare, Zimbabwe

SETTING

The tuberculosis (TB) service responsible for all TB treatment in Harare, Zimbabwe.

OBJECTIVES

(1) To determine HIV seroprevalence among TB patients and controls. (2) To compare clinical and demographic characteristics of HIV-infected and uninfected TB patients.

DESIGN

Cohort study. Entry criterion: TB diagnosed during the 18 month study period. Assessment included HIV serology. Matched community controls were HIV serotested.

RESULTS

In 1434 TB patients tested, HIV seroprevalence was 48% in men and 44% in women, peaked in the 25-34 year age group and was higher than in controls (relative risk [RR] = 3.1, 95% confidence interval [CI] = 2.6-3.7). In adults, seroprevalence was 34%, 49% and 58% in successive 6 month periods. A history of entry of prior TB treatment was less common in the HIV-seropositive (RR = 0.57, CI = 0.37-0.88). In adults, tuberculin negativity, TB at 2 sites, lymph node, pericardial and miliary TB, hilar adenopathy and pleural effusion were significantly more common in HIV-seropositive patients; cavitation and upper lobe involvement were significantly less frequent. Pulmonary TB and sputum smear positivity had similar frequencies in the 2 groups.

CONCLUSION

HIV was strongly and increasingly associated with TB in Harare and altered the clinical and radiologic features of TB. Failed standard TB treatment in HIV-infected individuals contributed minimally to new cases of TB.

Clinical application of microplate DNA-DNA hybridization procedure for rapid diagnosis of mycobacterial infections

SETTING

As an alternative to biochemical analysis, microplate DNA-DNA hybridization was applied for rapid diagnosis of mycobacterial infection.

OBJECTIVE

To assess how rapidly and correctly the microplate hybridization method can progress from clinical sample to final species identification of mycobacteria.

DESIGN

Clinical samples (pooled sputa or bronchial lavage fluid) were obtained from patients. Depending on the estimated bacterial amounts, genetic identification was performed either directly or following primary culture. Extracted DNA labeled by photobiotin was hybridized in microdilution wells with type-strain DNAs from 4 species (Mycobacterium tuberculosis, M. avium, M. intracellulare, and M. kansasii), the identified on the basis of genetic relatedness, which was quantitated by colorimetric detection.

RESULTS

With samples containing more than 10(8) colony-forming units [CFU] (5 cases), species identification was successfully performed on the day of sample preparation. With samples of not more than 10(7) CFU (14 cases), although 4-21 days' primary culture were necessary, species were also correctly identified by the microplate method. Furthermore, M. avium and M. intracellulare were distinctly identified. All the results precisely corresponded to those of biochemical analysis, which took 4-12 weeks to complete identification.

CONCLUSION

We consider that microplate DNA-DNA hybridization is a dependable technique for rapid diagnosis of mycobacterial infection.

New developments in tuberculosis and HIV infection: an opportunity for prevention

As we approach 2010, the year by which we were to have eliminated TB, we find this ancient disease is making a comeback. This comeback is due to many factors, but the role of HIV infection is clearly important. HIV infection can result in changes in the pathogenesis and presentation of infection with the tubercle bacillus. Consequently, as health care providers, we must respond with changes in our usual methods of prevention, treatment, and infection control. Whereas the increase in TB is currently limited to certain geographic areas, it is likely to spread more widely. All health care providers should be aware of the changing face of TB and have a high clinical index of suspicion for this disease.

Tuberculosis in patients with HIV infection

Tuberculosis is the most common opportunistic infection in patients with HIV infection worldwide and is the only one that is transmissible to others by the respiratory route. Tuberculosis is curable and preventable. Early detection of tuberculosis disease and infection in individuals with or at risk for HIV infection is paramount. This approach can minimize the devastating interaction between these two diseases.

The role of the public health department in tuberculosis

The role of the public health department in TB is a critical component of the overall TB control effort. This article illustrates both the traditional public health methods of surveillance, containment and prevention, and some of the newer strategies being employed to address TB control in today's multifaceted environment. It shows that controlling TB will require an intensification of collaborative efforts between public, private and community providers. In particular, the role of public health and health care workers in institutional settings is emphasized as it relates to shared community efforts. In light of the recent outbreaks of drug-resistant disease and the associated dramatic increasing TB morbidity and mortality, the need for these partnerships is urgent. Given the legal mandate for TB control, health departments will continue to play a major role in the elimination of this disease. The deterioration of these public health services, however, will require immediate attention lest the very foundation of TB control be allowed to crumble.