Tuberculosis and acquired immunodeficiency syndrome: a historical perspective on recent developments

Otolaryngological Manifestations of Tuberculosis: A Clinical Study

The aim of this study was to increase awareness of the different presentations of head and neck tuberculosis (TB) and to discuss its diagnostic difficulties. A prospective study of patients who presented to us, at a tertiary referral hospital, primarily with TB of head and neck was done from September 2014 to August 2016. Patients were categarised into proper category of Anti Tuberculous Treatment (ATT) and were treated according to ATT regimen. All patients were followed up at 2 months and 6 months after starting ATT. A total of 170 patients presented with primary head and neck TB during the study period. Most of these (96%) had cervical lymphadenopathy, 5 patients had laryngeal TB, and there was 1 patient each of TB of middle ear. 102 were males, and 68 were females. 25.8% of cases had associated pulmonary TB. (1) Diagnosing TB requires a high index of suspicion. (2) Tuberculosis of the cervical lymph nodes is the commonest presentation followed by laryngeal TB. (3) Fine needle aspiration cytology (FNAC) is a reliable and easy way to diagnose TB. However, newer diagnostic tests will increase the yield of positive cases and should be used whenever required. (4) In the larynx, the vocal cords were the commonest site affected and laryngeal TB need not be associated with lung TB or positive sputum always. (5) Patients who have TB of head and neck must be investigated to exclude pulmonary or systemic TB.

The bacterial and host factors associated with extrapulmonary dissemination of Mycobacterium tuberculosis

With high morbidity and mortality worldwide, tuberculosis (TB) is still an important public health threat. The majority of human TB cases are caused by Mycobacterium tuberculosis. Although pulmonary TB is the most common presentation, M. tuberculosis can disseminate into other organs and causes extrapulmonary TB (EPTB). The dissemination of bacteria from the initial site of infection to other organs can lead to fatal diseases, such as miliary and meningeal TB. Thoroughly understanding the mechanisms and pathways of dissemination would develop therapies to prevent the lethal prognosis of EPTB (miliary and meningeal TB) and vaccines to promote the development of adaptive immunity. This review focuses on risk factors of EPTB, bacterial and host genes involved in EPTB, and potential mechanisms of M. tuberculosis extrapulmonary dissemination.

Diagnosis and management of miliary tuberculosis: current state and future perspectives

Tuberculosis (TB) remains one of the most important causes of death from an infectious disease, and it poses formidable challenges to global health at the public health, scientific, and political level. Miliary TB is a potentially fatal form of TB that results from massive lymphohematogenous dissemination of Mycobacterium tuberculosis bacilli. The epidemiology of miliary TB has been altered by the emergence of the human immunodeficiency virus (HIV) infection and widespread use of immunosuppressive drugs. Diagnosis of miliary TB is a challenge that can perplex even the most experienced clinicians. There are nonspecific clinical symptoms, and the chest radiographs do not always reveal classical miliary changes. Atypical presentations like cryptic miliary TB and acute respiratory distress syndrome often lead to delayed diagnosis. High-resolution computed tomography (HRCT) is relatively more sensitive and shows randomly distributed miliary nodules. In extrapulmonary locations, ultrasonography, CT, and magnetic resonance imaging are useful in discerning the extent of organ involvement by lesions of miliary TB. Recently, positron-emission tomographic CT has been investigated as a promising tool for evaluation of suspected TB. Fundus examination for choroid tubercles, histopathological examination of tissue biopsy specimens, and rapid culture methods for isolation of M. tuberculosis in sputum, body fluids, and other body tissues aid in confirming the diagnosis. Several novel diagnostic tests have recently become available for detecting active TB disease, screening for latent M. tuberculosis infection, and identifying drug-resistant strains of M. tuberculosis. However, progress toward a robust point-of-care test has been limited, and novel biomarker discovery remains challenging. A high index of clinical suspicion and early diagnosis and timely institution of antituberculosis treatment can be lifesaving. Response to first-line antituberculosis drugs is good, but drug-induced hepatotoxicity and drug-drug interactions in HIV/TB coinfected patients create significant problems during treatment. Data available from randomized controlled trials are insufficient to define the optimum regimen and duration of treatment in patients with drug-sensitive as well as drug-resistant miliary TB, including those with HIV/AIDS, and the role of adjunctive corticosteroid treatment has not been properly studied. Research is going on worldwide in an attempt to provide a more effective vaccine than bacille Calmette-Guérin. This review highlights the epidemiology and clinical manifestation of miliary TB, challenges, recent advances, needs, and opportunities related to TB diagnostics and treatment.

Current concepts in the management of tuberculosis

Tuberculosis (TB) poses a serious threat to public health throughout the world but disproportionately afflicts low-income nations. Persons in close contact with a patient with active pulmonary TB and those from endemic regions of the world are at highest risk of primary infection, whereas patients with compromised immune systems are at highest risk of reactivation of latent TB infection (LTBI). Tuberculosis can affect any organ system. Clinical manifestations vary accordingly but often include fever, night sweats, and weight loss. Positive results on either a tuberculin skin test or an interferon-γ release assay in the absence of active TB establish a diagnosis of LTBI. A combination of epidemiological, clinical, radiographic, microbiological, and histopathologic features is used to establish the diagnosis of active TB. Patients with suspected active pulmonary TB should submit 3 sputum specimens for acid-fast bacilli smears and culture, with nucleic acid amplification testing performed on at least 1 specimen. For patients with LTBI, treatment with isoniazid for 9 months is preferred. Patients with active TB should be treated with multiple agents to achieve bacterial clearance, to reduce the risk of transmission, and to prevent the emergence of drug resistance. Directly observed therapy is recommended for the treatment of active TB. Health care professionals should collaborate, when possible, with local and state public health departments to care for patients with TB. Patients with drug-resistant TB or coinfection with human immunodeficiency virus should be treated in collaboration with TB specialists. Public health measures to prevent the spread of TB include appropriate respiratory isolation of patients with active pulmonary TB, contact investigation, and reduction of the LTBI burden.

Association of TNF-alpha-238G/A and 308 G/A gene polymorphisms with pulmonary tuberculosis among patients with coal worker's pneumoconiosis

OBJECTIVES

Tumor necrosis factor-alpha (TNF-alpha) may play an important role in host's immune response to mycobacterium tuberculosis (M. tuberculosis) infection. This study was to investigate the association of TNF-alpha gene polymorphism with pulmonary tuberculosis (TB) among patients with coal worker's pneumoconiosis (CWP).

METHODS

A case-control study was conducted in 113 patients with confirmed CWP complicated with pulmonary TB and 113 non-TB controls with CWP. They were matched in gender, age, job, and stage of pneumoconiosis. All participants were interviewed with questionnaires and their blood specimens were collected for genetic determination with informed consent. The TNF-alpha gene polymorphism was determined with polymerase chain reaction of restriction fragment length polymorphism (PCR-RFLP). Frequency of genotypes was assessed for Hardy-Weinberg equilibrium by chi-square test or Fisher's exact probability. Factors influencing the association of individual susceptibility with pulmonary TB were evaluated with logistic regression analysis. Gene-environment interaction was evaluated by a multiplicative model with combined OR. All data were analyzed using SAS version 8.2 software.

RESULTS

No significant difference in frequency of the TNF-alpha-308 genotype was found between CWP complicated with pulmonary TB and non-TB controls (chi2 = 5.44, P = 0.07). But difference in frequency of the TNF-alpha-308 A allele was identified between them (chi2 = 5.14, P = 0.02). No significant difference in frequencies of the TNF-alpha-238 genotype and allele (P = 0.23 and P = 0.09, respectively) was found between cases and controls either, with combined (GG and AA) OR of 3.96 (95% confidence interval of 1.30-12.09) at the -308 locus of the TNF-alpha gene, as compared to combination of the TNF-alpha-238 GG and TNF-alpha-308 GG genotypes. Multivariate-adjusted odds ratio of the TNF-alpha-238 GG and TNF-alpha-308 GA genotypes was 1.98 (95% CI of 1.06-3.71) for risk for pulmonary TB in patients with CWP. There was a synergic interaction between the TNF-alpha-308 GG genotype and body mass index (OR = 4.92), as well as an interaction between the TNF-alpha-308 GG genotype and history of BCG immunization or history of TB exposure. And, the interaction of the TNF-alpha-238 GG genotype and history of BCG immunization or TB exposure with risk for pulmonary TB in them was also indicated.

CONCLUSIONS

TNF-alpha-308 A allele is associated with an elevated risk for pulmonary TB, whereas TNF-alpha-238 A allele was otherwise.

Sex- and age-dependent association of SLC11A1 polymorphisms with tuberculosis in Chinese: a case control study

Background

Host genetic factors are important determinants in tuberculosis (TB). The SLC11A1 (or NRAMP1) gene has been studied extensively for genetic association with TB, but with inconsistent findings. In addition, no study has yet looked into the effect of sex and age on the relationship between SLC11A1 polymorphisms and TB.

Methods

A case-control study was conducted. In total, 278 pulmonary TB patients and 282 sex- and age-matched controls without TB were recruited. All subjects were ethnic Chinese. On the basis of linkage disequilibrium pattern, three genetic markers from SLC11A1 and one from the nearby IL8RB locus were selected and examined for association with TB susceptibility. These markers were genotyped using single strand conformation polymorphism analysis or fragment analysis of amplified products.

Results

Statistically significant differences in allele (P = 0.0165, OR = 1.51) and genotype (P = 0.0163, OR = 1.59) frequencies of the linked markers SLC6a/b (classically called D543N and 3'UTR) of the SLC11A1 locus were found between patients and controls. With stratification by sex, positive associations were identified in the female group for both allele (P = 0.0049, OR = 2.54) and genotype (P = 0.0075, OR = 2.74) frequencies. With stratification by age, positive associations were demonstrated in the young age group (age ≤65 years) for both allele (P = 0.0047, OR = 2.52) and genotype (P = 0.0031, OR = 2.92) frequencies. All positive findings remained significant even after correction for multiple comparisons. No significant differences were noted in either the male group or the older age group. No significant differences were found for the other markers (one SLC11A1 marker and one IL8RB marker) either.

Conclusion

This study confirmed the association between SLC11A1 and TB susceptibility and demonstrated for the first time that the association was restricted to females and the young age group.

The burden of HIV and AIDS on blood bank reserves in northeast Nigeria

This study was conducted to evaluate the burden of HIV/AIDS on blood bank reserves at the University of Maiduguri Teaching Hospital, Nigeria, during 1995-2005. The number of admissions due to HIV/AIDS rose from 43 in 1995 to 447 in 2005, and the proportion of blood units used in transfusing patients with HIV/AIDS rose steadily from 3% in 1995 to 19% in 2005. The proportion of blood units used in managing obstetric patients was also high and fluctuated between 36% and 50% during the period of study. Controlling the spread of HIV, effective treatment of patients with antiretroviral drugs and setting up a functional national blood transfusion service could lessen the rising burden of transfusion in Nigeria and improve blood availability for maternal and child health care.

Systematic review: tuberculous peritonitis--presenting features, diagnostic strategies and treatment

The peritoneum is one of the most common extrapulmonary sites of tuberculous infection. Peritoneal tuberculosis remains a significant problem in parts of the world where tuberculosis is prevalent. Increasing population migration, usage of more potent immunosuppressant therapy and the acquired immunodeficiency syndrome epidemic has contributed to a resurgence of this disease in regions where it had previously been largely controlled. Tuberculous peritonitis frequently complicates patients with underlying end-stage renal or liver disease that further adds to the diagnostic difficulty. The diagnosis of this disease, however, remains a challenge because of its insidious nature, the variability of its presentation and the limitations of available diagnostic tests. A high index of suspicion is needed whenever confronted with unexplained ascites, particularly in high-risk patients. Based on a systematic review of the literature, we recommend: tuberculous peritonitis should be considered in the differential diagnosis of all patients presenting with unexplained lymphocytic ascites and those with a serum-ascites albumin gradient (SAAG) of <11 g/L; culture growth of Mycobacterium of the ascitic fluid or peritoneal biopsy as the gold standard test; further studies to determine the role of polymerase chain reaction, ascitic adenosine deaminase and the BACTEC radiometric system for acceleration of mycobacterial identification as means of improving the diagnostic yield; increasing utilization of ultrasound and computerized tomographic scan for the diagnosis and as a guidance to obtain peritoneal biopsies; low threshold for diagnostic laparoscopy; treatment for 6 months with the first-line antituberculous drugs (isoniazid, rifampicin, ethambutol and pyrazinamide) in uncomplicated cases.

Miliary tuberculosis: new insights into an old disease

Miliary tuberculosis is a potentially lethal form of tuberculosis resulting from massive lymphohaematogeneous dissemination of Mycobacterium tuberculosis bacilli. The emergence of the HIV/AIDS pandemic and widespread use of immunosuppressive drugs has changed the epidemiology of miliary tuberculosis. Impaired cell-mediated immunity underlies the disease's development. Clinical manifestations are non-specific and typical chest radiographic findings may not be seen until late in the course of the disease. Atypical presentations--eg, cryptic miliary tuberculosis and acute respiratory distress syndrome--often delay the diagnosis. Several laboratory abnormalities with prognostic and therapeutic implications have been described, including pulmonary function and gas exchange impairment. Isolation of M tuberculosis from sputum, body fluids, or biopsy specimens, application of molecular methods such as PCR, and histopathological examination of tissue biopsy specimens are useful for the confirmation of diagnosis. Although response to first-line antituberculosis drugs is good, evidence regarding optimum duration of treatment is lacking and the role of adjunctive corticosteroid treatment is unclear.

Cytokine responses induced by Mycobacterium tuberculosis in patients with HIV-1 infection and tuberculosis

OBJECTIVE

Tuberculosis (TB) is an important opportunistic infection in HIV patients. Immune responses to Mycobacterium tuberculosis in HIV/TB patients were evaluated.

METHODS

Fifteen patients with HIV/TB, ten with HIV, four with TB, and five controls were enrolled. Peripheral blood mononuclear cells were isolated and stimulated with mycobacterial antigen (PPD). Interferon (IFN)-gamma and TNF-alpha in culture supernatants were measured by ELISA.

RESULTS

IFN-gamma and TNF-alpha production after PPD stimulation was markedly decreased in HIV patients, but not in HIV/TB patients. In HIV patients with a CD4 cell count of less than 200/mm3, IFN-gamma and TNF-alpha production after PPD stimulation was higher in HIV/TB patients than in HIV patients. Cytokine responses to M. tuberculosis reconstituted after highly active antiretroviral therapy (HAART) and were prominent in HIV/TB patients.

CONCLUSIONS

Cytokine responses to M. tuberculosis were retained in HIV-infected patients with tuberculosis, even in patients with a CD4 cell count of less than 200/mm3, and reconstituted after HAART.

Invasion of the central nervous system by intracellular bacteria

Infection of the central nervous system (CNS) is a severe and frequently fatal event during the course of many diseases caused by microbes with predominantly intracellular life cycles. Examples of these include the facultative intracellular bacteria Listeria monocytogenes, Mycobacterium tuberculosis, and Brucella and Salmonella spp. and obligate intracellular microbes of the Rickettsiaceae family and Tropheryma whipplei. Unfortunately, the mechanisms used by intracellular bacterial pathogens to enter the CNS are less well known than those used by bacterial pathogens with an extracellular life cycle. The goal of this review is to elaborate on the means by which intracellular bacterial pathogens establish infection within the CNS. This review encompasses the clinical and pathological findings that pertain to the CNS infection in humans and includes experimental data from animal models that illuminate how these microbes enter the CNS. Recent experimental data showing that L. monocytogenes can invade the CNS by more than one mechanism make it a useful model for discussing the various routes for neuroinvasion used by intracellular bacterial pathogens.

[Drugs with activity against Mycobacterium tuberculosis]

Treatment for Mycobacterium tuberculosis has to be lengthy, since populations of this bacillus differ in metabolic activity, and it has to consist of various associated drugs, since spontaneous chromosome mutations can give rise to drug resistance. The multiresistant phenotype emerges with sequential acquisition of mutations in several loci of separate genes. Knowledge of the mechanisms of resistance permits the development of molecular techniques for the early detection of resistant strains, thereby making proper control possible. Tuberculosis treatment includes isoniazid, rifampicin and pyrazinamide during the first two months and isoniazid and rifampicin to complete six months of treatment. In specific situations, a fourth drug is added, ethambutol for adults and streptomycin for children in whom visual acuity cannot be monitored. This review describes the characteristics, activity, resistance mechanisms and side effects associated with the various antituberculosis drugs.

Impact of human immunodeficiency virus 1 infection on clinical presentation, treatment outcome and survival in a cohort of Ethiopian children with tuberculosis

BACKGROUND

Childhood tuberculosis (TB) is difficult to diagnose reliably because signs and symptoms are nonspecific and sputum for direct microscopy is difficult to obtain, especially in very young children. This diagnostic dilemma is thought to have increased with the HIV pandemic. Few studies on treatment outcome of dually infected children in high endemic countries have been reported. This study examines the impact of HIV infection on clinical presentation, diagnostic criteria and treatment outcome of TB in Ethiopian children.

METHODS

A prospective cohort study of children with TB diagnosed in Addis Ababa from December 1995 to January 1997 in which HIV-positive children were compared with HIV-negative children with regard to medical history, signs and symptoms, nutritional status, chest radiography, tuberculin skin test, response to TB treatment and final outcome. Mycobacterium tuberculosis was cultured in children with pulmonary manifestations.

RESULTS

HIV-positive children were younger, were underweight and had a 6-fold higher mortality than HIV-negative children. The tuberculin skin test was less sensitive and chest radiography was less specific in HIV-infected patients. Adherence to treatment was high (96%), and the cure rate was 58% for HIV-positive and 89% for HIV-negative TB patients.

CONCLUSION

HIV-positive children are at risk of diagnostic error as well as delayed diagnosis of TB. TB manifestations are more severe and progression to death is more rapid than in HIV-negative children. Weight for age may be used to identify children at high risk of a fatal outcome.

Sinopulmonary complications of illicit drug use

Illicit drug use is frequently complicated by sinopulmonary illnesses. These complications fall into two major categories: (1) direct effects of drug exposure, and (2) indirect effects caused by HIV-induced immunosuppression. This article reviews the more common sinopulmonary syndromes associated with illicit drug use.

[Multiorgan tuberculosis]

Tuberculosis is an unusual infectious disease because of the latent period between the infection and the appearance of the disease may be prolonged for many weeks, months, or years as it is in case of the secondary tuberculosis. Tuberculosis in organs other than the lung has been observed for many years but has not always been recognized as tuberculosis, and it has been given many names. Extrapulmonary tuberculosis gained new importance, because it represented a progressively greater proportion of new cases. Multiple extrapulmonary sites were reported rarely except for one anatomical site, which was reported frequently. Extrapulmonary rates increase with age, so there are marked differences in age in specific rate patterns among the sites. Extrapulmonary tuberculosis occurred in respiratory organs other than lung, such as lymphatic, urogenital, and central nervous system, abdominal, osteoarticular, as well as tuberculosis of other organs such as skin, pericardium and endocrine glands. This case was reported to analyse clinical, morphologic and laboratory characteristics, method of diagnosis and the outcome in patients with multiorgan tuberculosis in order to explore the factors which might contribute to the decision making, concerning these forms of tuberculosis. Recent knowledge of pathogenesis was summarized as well as clinical presentation and the effects of cytokines produced by T lymphocytes and cellular population on antimycobacterial immune defences, and also susceptibility to tuberculosis. Mortality remains high and the treatment should start as soon as tuberculosis is suspected.

Value of mandatory testing for human immunodeficiency virus in a sub-Saharan hospital population

Human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) are currently hyperendemic in sub-Saharan Africa. HIV and AIDS have a special impact on working-age populations, economic resources, certain illnesses, and health care facilities. Assessment of HIV serostatus of hospitalized patients is rarely performed, however, because of a reluctance to intrude on patient confidentiality, a perceived lack of benefit (no antiretroviral therapy is available), and societal denial. We evaluated the effect on health care of HIV testing of patients routinely admitted to medical wards in the 2 major city hospitals in Harare, Zimbabwe. Of 196 patients tested, 58% were HIV positive with strong associations with infectious diseases, and with youth and weight loss, but not with cardiac, pulmonary, endocrinologic, or renal diagnoses, and not with rural versus urban location, occupation, sex, mortality, or cost of hospitalization. The clinical estimate of patients' HIV serostatus was largely inaccurate. Mandatory HIV testing of all hospitalized patients would improve diagnosis of infectious diseases, clarify patient prognosis, allow for individual counseling with regard to HIV prevention, and focus national health efforts by providing alarming, realistic statistics.

HIV AND TUBERCULOSIS CO-INFECTION IN A REFERRAL CHEST HOSPITAL

Serving personnel of Armed Forces admitted with tuberculosis between Apr 1996-1999 were evaluated for co-infection of tuberculosis and HIV. Sixty (1.06%) of tuberculosis patients were found to be HIV positive. Initial test was done by spot kits and subsequently confirmed by ELISA on two different samples. Majority of the cases were in sexually active age group 48 (80%). Alcohol and smoking was associated in 80% cases. Thirty six (60%) were sputum smear positive for AFB. Twenty eight (46.7%) gave history of exposure to sex workers. Family members were not available for study. Sero prevalence of HIV in association with tuberculosis is less in Armed Forces compared to civil population.

Superior vena cava syndrome during the treatment of pulmonary tuberculosis in an HIV-1 infected patient

Tuberculosis is nowadays an uncommon cause of superior vena cava syndrome (SVCS). We report the case of an HIV-infected patient who presented with respiratory symptoms accompanied by cervical and mediastinal lymphadenopathy. Sputum examination showed acid-fast bacilli, and treatment was instituted with isoniazid, rifampicin, pyrazinamide and ethambutol. A few days later SVCS developed, presumably as a consequence of inflammatory lymphadenitis. With corticosteroids, all symptoms disappeared. To our knowledge, no cases of SVCS provoked by this kind of paradoxical reaction have been described previously.

Clinical presentation of tuberculosis and the degree of immunodeficiency in patients with HIV infection

A retrospective study of 80 HIV patients diagnosed with tuberculosis was carried out in order to evaluate the clinical presentation of tuberculosis (CPT) in relation to the degree of HIV-induced immunodeficiency, as determined by the CD4 lymphocyte count and reactivity to the tuberculin and delayed-type hypersensitivity reaction (DHR) skin tests by applying 2TU of RT-23 tuberculin, and the Muiltest IMC Merieux, respectively. CPT classification was undertaken on the basis of the location of the disease: pulmonary tuberculosis (PT), distinguishing between typical pulmonary (TP) and atypical (AP) according to the radiological pattern; extrapulmonary (ET); mixed tuberculosis (MT) pulmonary and extrapulmonary; and miliary tuberculosis. The CD4 lymphocyte count was 264.6 +/- 226.8, the TP had the highest number (505), MT had 132 (p < 0.001) and the miliary tuberculosis had 148 (p < 0.001), the lowest. The tuberculin skin test was positive in 35%, of which 11% were MT (p < 0.05). In the delayed-type hypersensitivity reaction, 67% were non-normoergic, of which 95% and 100% were MT and miliary tuberculosis, respectively (p < 0.05). There was a good overlap between CD4 depletion and skin tests. TP exhibited moderate immunodeficiency, AP severe immunodeficiency, and mixed and miliary TB extremely high immunodeficiency.

Comparison of the construction of unmarked deletion mutations in Mycobacterium smegmatis, Mycobacterium bovis bacillus Calmette-Guérin, and Mycobacterium tuberculosis H37Rv by allelic exchange

Until recently, genetic analysis of Mycobacterium tuberculosis, the causative agent of tuberculosis, was hindered by a lack of methods for gene disruptions and allelic exchange. Several groups have described different methods for disrupting genes marked with antibiotic resistance determinants in the slow-growing organisms Mycobacterium bovis bacillus Calmette-Guérin (BCG) and M. tuberculosis. In this study, we described the first report of using a mycobacterial suicidal plasmid bearing the counterselectable marker sacB for the allelic exchange of unmarked deletion mutations in the chromosomes of two substrains of M. bovis BCG and M. tuberculosis H37Rv. In addition, our comparison of the recombination frequencies in these two slow-growing species and that of the fast-growing organism Mycobacterium smegmatis suggests that the homologous recombination machinery of the three species is equally efficient. The mutants constructed here have deletions in the lysA gene, encoding meso-diaminopimelate decarboxylase, an enzyme catalyzing the last step in lysine biosynthesis. We observed striking differences in the lysine auxotrophic phenotypes of these three species of mycobacteria. The M. smegmatis mutant can grow on lysine-supplemented defined medium or complex rich medium, while the BCG mutants grow only on lysine-supplemented defined medium and are unable to form colonies on complex rich medium. The M. tuberculosis lysine auxotroph requires 25-fold more lysine on defined medium than do the other mutants and is dependent upon the detergent Tween 80. The mutants described in this work are potential vaccine candidates and can also be used for studies of cell wall biosynthesis and amino acid metabolism.

[Disseminated tuberculosis in non-immunocompromised host: three case reports]

INTRODUCTION

Disseminated tuberculosis, i.e., tuberculosis involving lung, liver, spleen, bone marrow and lymph nodes is rare (2.8%), particularly when immunocompromised diathesis is lacking.

EXEGESIS

We report three cases of disseminated tuberculosis confirmed by bacteriology or histology, which occurred in non-immunocompromised patients. Disease evolution under antituberculous treatment was favorable in two cases and fatal in the third one.

CONCLUSION

Disseminated tuberculosis must be suspected when miliary pulmonary lesions are associated with hematologic abnormalities, even in non-immunocompromised host. Early treatment is mandatory to avoid fatal outcome.

Pulmonary tuberculosis in Harare, Zimbabwe: analysis by spoligotyping

BACKGROUND

Over the last 10 years there has been a fourfold increase in cases of tuberculosis in Harare, Zimbabwe. The use of molecular epidemiology to understand tuberculosis transmission in this epidemic has been hampered by the availability of suitable culture facilities. A study was therefore undertaken to explore the potential of spoligotyping, a polymerase chain reaction based technique that does not require tuberculosis culture.

METHODS

Adults attending a chest clinic with clinical or radiological pulmonary tuberculosis and one smear positive sputum were enrolled over one month. Demographic, socioeconomic, and clinical data were gathered using a standardised questionnaire. Molecular fingerprinting of genomic DNA recovered from sputum was performed by spoligotyping.

RESULTS

Sixty one subjects (median age 28 years (range 18-73); 61% men) were recruited and 57 provided adequate sputum samples. Recent rural-urban migration or immigration was not common; 40% of subjects lived in crowded living conditions. DNA suitable for spoligotyping was recovered from 28 patients and 20 different genotypes of Mycobacterium tuberculosis were identified. Fifteen patients were infected with an M tuberculosis strain shared by one or more individuals. Patients infected with a shared spoligotype were not closely linked geographically within Harare, but were more likely to live in overcrowded conditions (69% versus 23%; odds ratio 6.85 (95% CI 1.2 to 47), p = 0.026). Analysis of the patients' original rural family homes revealed two geographically related spoligotype clusters.

CONCLUSIONS

Spoligotyping may yield valuable molecular typing information in populations where tuberculosis culture is not available. This novel technique requires further development and evaluation in larger epidemiological studies.

Multi-drug resistant tuberculosis in Finland--a forecast

Since the collapse of the Soviet system, travel between the St Petersburg district and the Baltic states and Finland has increased substantially. Although it is difficult to obtain exact figures on the number of cases of tuberculosis (TB) and multi-drug resistant (MDR) TB in these countries, there is strong evidence of growing epidemics, bringing added epidemiological threat to Finland. The purpose of this study is to produce a short-term "worst case" forecast of the spatial development of a threatened MDR-TB epidemic in Finland. The method applied is a chorological multistep procedure using statistical and geographical methods and a simulation technique. Instead of focusing on populations of carriers and susceptibles, emphasis is placed on identifying the primary influences directing the epidemic as a spatial process. This was done by dividing Finland into small-area units and by assigning the risk of obtaining MDR-TB to each unit based on socioeconomic and structural characteristics of the population. The simulated 6 year cumulative distribution of new MDR-TB cases showed a marked concentration of cases in the capital region and in a cluster of municipalities along the west coast. Although socioeconomic factors are important in explaining the distribution of cases, frequent and widespread international contacts seemed to be equally important at the beginning of the epidemic.

The yield of bone marrow biopsy and culture compared with blood culture in the evaluation of HIV-infected patients for mycobacterial and fungal infections

PURPOSE

To compare the clinical utility of bone marrow biopsy and culture specimens with blood cultures for mycobacterial and fungal infections among human immunodeficiency virus (HIV)-infected patients.

PATIENTS AND METHODS

All bone marrow biopsies obtained from HIV-infected patients at the University of Alabama at Birmingham (UAB) Medical Center during 1993 to 1995 were blindly reviewed in a standardized format. Bone marrow culture results and blood culture results obtained within 6 weeks of each bone marrow study were compiled. Medical records were reviewed to determine indications for performing bone marrow biopsies, empiric or prophylactic antimicrobial therapies preceding the biopsy, and CD4 counts.

RESULTS

Eighty-two bone marrow studies were obtained from 76 patients. Most were performed during the evaluation of fever, cytopenia, or weight loss. Of 55 bone marrow mycobacterial cultures, 13 yielded Mycobacterium avium complex (MAC) and 2 yielded M tuberculosis (MTB). Of 51 bone marrow fungal cultures performed, 2 yielded Cryptococcus neoformans and 1 Histoplasma capsulatum. All patients with a bone marrow culture positive for MAC had a CD4 count of 20 cells/mm3 or less. The mean CD4 count in this group (+/-95% confidence interval) (8+/-3 cells/mm3) was lower than that of culture-negative cases (41+/-25 cells/mm3); P <0.015). When bone marrow cultures and mycobacterial blood cultures were concurrently obtained, results were usually in agreement between the two sites. The mean time until the report of positive mycobacterial bone marrow cultures (22+/-5 days) was similar to that for blood cultures (24+/-3 days). Most (84%) patients with multiple mycobacterial cultures had completely concordant results (all positive or all negative). When blood or bone marrow culture yielded mycobacteria, only 29% of the corresponding bone marrow examinations revealed stainable acid-fast bacilli (AFB). In contrast, all 3 cases with positive fungal bone marrow cultures also had stainable organisms on histologic examination.

CONCLUSIONS

The combined use of bone marrow biopsy and culture as well as blood cultures provide the maximum diagnostic yield when evaluating patients with AIDS for mycobacterial or fungal infections. However, when mycobacterial infections were diagnosed, bone marrow results seldom provided more immediate or specific information than lysis centrifugation blood cultures. A single lysis centrifugation blood culture should be the first step in the routine evaluation of HIV-infected patients when disseminated MAC infection is suspected.

Tuberculous pericarditis and AIDS: case reports and review

Pericarditis is one of the most common cardiac complications in the course of HIV disease. Opportunistic infections and neoplastic processes represent the most common etiology of pericardial disease. Pericardial tuberculosis is an uncommon condition, especially in developed countries. Two cases of tuberculous pericarditis in adult patients with AIDS occurred over a 12-month period at our clinic, which prompted a literature review of the published cases of tuberculous pericarditis in AIDS. Of note is that in the first patient pericardial effusion represented the AIDS-defining illness and was an expression of a disseminated tuberculous disease. The second patient developed a fatal pericarditis due to a multiple-drug resistant Mycobacterium tuberculosis infection.

Tuberculous meningitis at a large inner-city medical center

Tuberculosis in the United States has become primarily an inner-city disease. We examined the epidemiology of culture-confirmed tuberculous meningitis among patients cared for at an urban public hospital in Atlanta. During an 11.5-year period (January 1984-June 1995) cerebrospinal fluid cultures for Mycobacterium tuberculosis were positive in 34 patients, accounting for 1.5% of all culture-confirmed tuberculosis cases. All patients were born in the United States, 31 (91%) were black, 16 (47%) of 34 were human immunodeficiency virus (HIV) seropositive, 9 (26.5%) were HIV seronegative, and 9 (26.5%) had an unknown HIV serostatus. No significant differences were seen in clinical presentation, cerebrospinal fluid, or other laboratory data between HIV seropositive and HIV seronegative/ unknown groups, except for a lower serum white blood cell count among HIV seropositive patients. Mortality was striking; 14 (41.2%) died because of tuberculous meningitis despite appropriate therapy initiated a mean of 3 days after admission. Six survivors had permanent neurologic sequelae. Univariate analysis of outcome was not statistically associated with any measured demographic, laboratory value, stage at presentation, treatment regimen, or HIV serostatus. Multivariate analysis of outcome using 13 independent variables also demonstrated no significant association between these variables and outcome, although a trend was seen for increased mortality for white people (P = 0.09) and increasing age (P = 0.09). Tuberculous meningitis among inner-city residents remains a devastating disease associated with high morbidity and mortality that has changed little during the past 4 decades. HIV infection does not change markedly the clinical presentation or the response to therapy.

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.

Ocular tuberculosis. A prospective study in a general hospital

Ocular tuberculosis has traditionally been considered uncommon or anecdotal. Imprecise and variable diagnostic criteria have contributed to the confusion surrounding this topic. The increase in extrapulmonary manifestations of tuberculosis during the AIDS era established the need for a prospective study of ocular involvement in patients with all types of tuberculosis using well-defined criteria. During a 15-month period, 300 cases had culture-proven tuberculosis at our institution. We randomly selected 100 for systematic ophthalmologic evaluation. Our criteria for ocular tuberculosis were divided as follows: certainty (isolation of Mycobacterium tuberculosis from ocular specimens), probability (patients with isolation of M. tuberculosis from extraocular samples, with ocular lesions not attributable to other causes that respond to anti-tuberculous treatment), and possibility (same as probability but follow-up impossible). Ocular tuberculosis was present in 18 patients (18%) of which 10 patients fulfilled probability and 8 patients fulfilled possibility criteria. Eleven of 18 patients had HIV infection. In 11 patients, ocular involvement was asymptomatic. Almost all patients (17/18) had choroiditis, and other ocular lesions included papillitis, retinitis, vitritis, vasculitis, dacryoadenitis, and scleritis. Multivariate analysis showed as risk factors independently predicting ocular involvement in patients with ocular tuberculosis the presence of miliary disease (odd ratio 43.92, p = 0.002), ocular symptoms (odds ratio 6.35, p = 0.0143), and decreased visual acuity (odds ratio 0.04, p = 0.012). We observed an unexpectedly high (18%) incidence of ocular involvement, frequently asymptomatic, in patients with tuberculosis. Miliary disease is a clear predisposing factor in both HIV-infected and noninfected populations. Ocular examination should be routinely considered in patients with proven or suspected tuberculosis.

Corticosteroids in tuberculosis

OBJECTIVE

To examine the effects of corticosteroids used for concomitant disease states in patients with latent or active tuberculosis (TB). The role of corticosteroids in the treatment of extrapulmonary TB is also discussed.

DATA SOURCES

A MEDLINE search was conducted for the years 1953-1995. The International Pharmaceutical Abstracts service was also used to conduct an extensive literature review. In addition, relevant articles were cross-referenced to screen for additional information.

STUDY SELECTION/DATA EXTRACTION

During the literature review, emphasis was placed on human studies and individual case reports.

DATA SYNTHESIS

The resurgence of TB in this decade has affected many populations, especially immunocompromised patients. These patients may need corticosteroid therapy for various concomitant diseases that might predispose a patient to develop primary TB infection or reactivate latent TB infection. In appropriate patients, prophylaxis with isoniazid is recommended. Corticosteroid therapy may benefit patients with some forms of extrapulmonary TB. After steroid therapy, improved survival and more rapid reduction of tuberculous symptoms have been noted in cases of tuberculous pleurisy, endobronchial TB, tuberculous meningitis, and tuberculous pericarditis. Corticosteroids may also be useful in controlling both fever and hypersensitivity reactions in pulmonary and extrapulmonary TB, although not routinely used for this purpose.

CONCLUSIONS

Corticosteroids may play an important role in TB infection by promoting reactivation of latent infection. Corticosteroids may modify symptoms of some forms of extrapulmonary TB, although randomized, placebo-controlled studies are needed before corticosteroids will have a definitive place in the standard therapy of TB.

Biosynthesis of diaminopimelate, the precursor of lysine and a component of peptidoglycan, is an essential function of Mycobacterium smegmatis

Diaminopimelate (DAP) is a unique metabolite used for both the biosynthesis of lysine in bacteria and the construction of the peptidoglycan of many species of bacteria, including mycobacteria. DAP is synthesized by bacteria as part of the aspartate amino acid family, which includes methionine, threonine, isoleucine, and lysine. Aspartokinase, the first enzyme in this pathway, is encoded by the ask gene in mycobacteria. Previous attempts to disrupt this gene in Mycobacterium smegmatis were unsuccessful, even when the cells were supplied with all the members of the aspartate family, suggesting that unlike other bacteria, mycobacteria may have an absolute requirement for this pathway even when growing in rich medium containing DAP. The purpose of this study was to determine if the ask gene and the aspartate pathway are essential to M. smegmatis. This study describes a test for gene essentiality in mycobacteria, utilizing a counterselectable marker (streptomycin resistance) in conjunction with a specially constructed merodiploid strain. We have used this system to show that the ask gene could not be disrupted in wild-type M. smegmatis, using selective rich medium supplemented with DAP unless there was an extra copy of ask provided elsewhere in the chromosome. Disruption of ask was also possible in a lysine auxotroph incapable of converting DAP to lysine. The ask mutant, mc21278 (ask1::aph), exhibits multiple auxotrophy (Met-, Thr-, DAP-, and Lys-) and is complemented by the ask gene. This is the first description of DAP auxotrophy in mycobacteria. The ask mutant lyses when deprived of DAP in culture, a characteristic which can be exploited for the reproducible preparation of protoplasts and mycobacterial extracts. The evidence presented here indicates that the aspartate pathway is essential to M. smegmatis and that DAP is the essential product of this pathway.

Comparative histopathological study of pulmonary tuberculosis in human immunodeficiency virus-infected and non-infected patients

SETTING

Clinical features of human immunodeficiency virus (HIV)-associated tuberculosis depend upon the patients' residual immunity. An immune-dependent presentation has also been described at the histopathological level in many extra-pulmonary sites, but no descriptions have so far been made on the histopathology of HIV-associated pulmonary tuberculosis.

OBJECTIVE

To compare the histopathological features of pulmonary tuberculosis in HIV-infected subjects and seronegative patients.

DESIGN

We carried out a retrospective comparative study on 16 HIV-infected subjects and 16 seronegative patients with culture-proven pulmonary tuberculosis who underwent transbronchial biopsy. We evaluated the bacillary burden and the parenchymal inflammatory reaction by means of a four-graded scoring system giving an approximate quantitative measure of the two parameters.

RESULTS

HIV-associated pulmonary tuberculosis was found to differ significantly from disease forms seen in seronegative patients, with a significant tendency to develop highly bacillary and poorly reactive histopathological pictures along with the downgrading evolution of immune function.

CONCLUSION

Pathologic features of pulmonary tuberculosis in HIV-infected subjects differ from those encountered in seronegative patients depending upon the individual immunity of the former. HIV-associated progressive depletion of CD4+ lymphocytes leads to substantial changes in pulmonary reactivity to Mycobacterium tuberculosis; multibacillary pictures in a background of loose inflammatory reactions are quite common findings at the extreme phase of HIV-related immune deterioration.

Mycobacterial infection in Mexican AIDS patients

To describe the characteristics of mycobacterial infection in Mexico, we reviewed records from patients who were seen at the AIDS Clinic of the National Institute of Nutrition in Mexico City from 1983 to 1992. Of 460 AIDS patients, 118 (25.6%) were found to have mycobacterial infections by positive Ziehl-Neelsen stain, culture, or both. Cultures were completed for 66 of the 118 stain-positive specimens. Mycobacterium tuberculosis was the most common species found (n = 13), followed by M. avium complex (n = 12); 21 infections were identified a nonspecific mycobacteria other than tuberculosis (MOTT) and 20 infections were from species other than tuberculosis. Susceptibility testing was performed in only two tuberculosis cases, with one strain showing multidrug resistance. We conclude that mycobacterial infection is common among our AIDS population, and MOTT may be at least as common as M. tuberculosis. Previous reports of the rarity of MOTT could be related to the lack of adequate diagnostic methods in developing countries.

Synergistic activities of clarithromycin and antituberculous drugs against multidrug-resistant Mycobacterium tuberculosis

The rise of multidrug-resistant Mycobacterium tuberculosis has complicated therapy for tuberculosis and led us to search for a potentially active combination of drugs against these strains. The susceptibilities of 12 strains of multidrug-resistant M. tuberculosis to standard antituberculous drugs (isoniazid, rifampin, ethambutol, and pyrazinamide), clarithromycin, and its metabolite, 14-hydroxyclarithromycin, were determined by use of the BACTEC radiometric method. All strains were resistant to at least two of the antituberculous drugs. Clarithromycin and 14-hydroxyclarithromycin MICs were in the range indicating resistance at > or = 8.0 micrograms/ml for all strains. Combination testing by the BACTEC method was performed with various concentrations of isoniazid, rifampin, and ethambutol, and with clarithromycin/14-hydroxyclarithromycin at fixed concentrations of 2.0/0.5 micrograms/ml, respectively. Addition of clarithromycin/14-hydroxyclarithromycin to these antituberculous drug mixtures resulted in a 4- to 32-fold reduction in MICs of isoniazid, rifampin, and ethambutol and made resistant strains susceptible. Fractional inhibitory concentrations ranged from 0.23 to 0.50 for all strains, suggesting a synergistic interaction between standard antituberculous drugs and clarithromycin/14-hydroxyclarithromycin. The ability of clarithromycin/14-hydroxyclarithromycin to enhance the activities of isoniazid, ethambutol, and rifampin in vitro suggests that this combination may be efficacious in the treatment of multidrug-resistant M. tuberculosis infections.

Inner-city tuberculosis in the USA

Tuberculosis (TB) has become more common during the past five years in several areas of the USA. Occurrence has been facilitated by the increasing number of patients with concurrent HIV infection, by cases due to multiple-drug-resistant strains, by incomplete TB therapy among homeless and non-compliant patients, and by cases in immigrants from other countries where TB prevalence is high. These features mean that the major burden of TB today is being borne by inner-city health care facilities that care for the poor. This is illustrated by data from Atlanta, Georgia, where a large proportion of the new cases recognized in the metropolitan area are reported by Grady Memorial Hospital, the public hospital serving the indigent and working poor of the inner city. Similar patterns are recognized in the other USA cities where TB has again become a blight. In view of these epidemiological features, minimizing inner-city TB will require careful attention to diagnosis and isolation procedures in the hospital. Engineering changes at hospitals providing acute care of TB have recently been ordered by the federal government. These promise to be very expensive, and primarily affect the public hospitals, which can least afford them. Innovative treatment programmes are essential, as follow-up after acute care is difficult in this setting. Directly observed therapy can help, but for some cases the era of the TB hospital may have returned. Current attention focuses on legal and ethical issues associated with detaining non-compliant and recalcitrant patients to complete their therapy. Bacille Calmette Guerin (BCG) vaccine is not a priority for this setting at this time.(ABSTRACT TRUNCATED AT 250 WORDS)

Tuberculosis in the AIDS era

A resurgence of tuberculosis has occurred in recent years in the United States and abroad. Deteriorating public health services, increasing numbers of immigrants from countries of endemicity, and coinfection with the human immunodeficiency virus (HIV) have contributed to the rise in the number of cases diagnosed in the United States. Outbreaks of resistant tuberculosis, which responds poorly to therapy, have occurred in hospitals and other settings, affecting patients and health care workers. This review covers the pathogenesis, epidemiology, clinical presentation, laboratory diagnosis, and treatment of Mycobacterium tuberculosis infection and disease. In addition, public health and hospital infection control strategies are detailed. Newer approaches to epidemiologic investigation, including use of restriction fragment length polymorphism analysis, are discussed. Detailed consideration of the interaction between HIV infection and tuberculosis is given. We also review the latest techniques in laboratory evaluation, including the radiometric culture system, DNA probes, and PCR. Current recommendations for therapy of tuberculosis, including multidrug-resistant tuberculosis, are given. Finally, the special problem of prophylaxis of persons exposed to multidrug-resistant tuberculosis is considered.

HIV and tuberculosis: noncompliance revisited

Revisiting the stereotype of the noncompliant patient can transcend the frustrating or resentful feelings nurses may experience when caring for patients with HIV and tuberculosis. This reevaluation also can lend itself to developing mutually participative nurse-patient relationships. The author suggests relationship goals, assessment parameters, and intervention strategies--including a directly observed therapy (DOT) contract. These actions support a commitment to empowering both the nurse and the patient in their relationship in the TB treatment process.