ArticlesUnrecognised Mycobacterium tuberculosis bacteraemia among hospital inpatients in less developed countries
Introduction
Mycobacterium tuberculosis is a growing, worldwide public-health threat. About a third of the world's population is infected; M tuberculosis causes up to three million deaths annually.1 The burden of active tuberculosis is spread disproportionately between two key regions: southeast Asia and sub-Saharan Africa. Of about 40 million episodes of active tuberculosis that will have occurred in young adults worldwide between 1990 and 2000, more than 28 million will have occurred in southeast Asia, and 9 million in sub-Saharan Africa.1
The HIV pandemic has contributed to the increased spread of tuberculosis; HIV-infected patients are 30 times more likely to develop active tuberculosis and become infectious than are HIV-negative individuals.1 Of the estimated 20 million individuals with HIV infection or AIDS in the world in 1997, more than five million were diagnosed in southeast Asia, and 14 million in sub-Saharan Africa.2 In these regions, where both HIV and M tuberculosis infections are prevalent, the hospital setting may have an important role in the spread of M tuberculosis.
Prevention of nosocomial transmission of M tuberculosis requires early clinical recognition of patients with active disease so that isolation precautions can be taken and therapy promptly initiated.3 However, recognition of tuberculosis can be difficult in HIV-infected patients; many such patients present with atypical signs and symptoms, and they are susceptible to various other pulmonary infections that can mimic tuberculosis and make diagnosis difficult.4, 5, 6, 7, 8 Although simple diagnostic tests, such as chest radiographs9 and sputum smears,7 may assist in the recognition of active disease in hospital inpatients, resources for carrying out such diagnostic tests are limited in many less developed countries.
Mycobacteraemia is a key event in the pathogenesis of tuberculosis, and is detected in many HIV-infected patients with active tuberculosis.10, 11, 12M tuberculosis is now being recognised as an important cause of bacteraemia in less developed countries.13, 14 However, clinicians in these regions frequently do not suspect underlying mycobacteraemia, and therefore do not request appropriate blood cultures. In addition, lack or inappropriate use of clinical microbiology resources in hospitals in less developed countries, or the absence of clinical algorithms for making the decision to obtain M tuberculosis blood cultures from patients suspected of having mycobacteraemia, may contribute to low detection rates of this disease.
We did a blood-culture survey in hospitals in southeast Asia and sub-Saharan Africa to measure the prevalence of M tuberculosis bacteraemia among febrile, adult inpatients; to find out whether active tuberculosis in febrile patients with M tuberculosis bacteraemia is, in practice, frequently unrecognised; and to assess factors associated with the under-recognition of active disease in patients with M tuberculosis bacteraemia.
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Study population
The surveys were carried out in an infectious-disease hospital near Bangkok, Thailand, during February and March, 1997, and at a government-run, general hospital in Lilongwe, Malawi, during August and September, 1997. Approval of the study protocol was obtained from the institutional review boards at the Centers for Disease Control and Prevention (GA, USA) and at the hospitals in Thailand and Malawi.
We recruited consecutive adult patients (aged ⩾18 years) who were febrile (oral temperature
Results
344 patients (216 in Thailand and 128 in Malawi) were enrolled at the two sites (table 1). Of those originally approached, no patients in Thailand, and four in Malawi declined to participate. A greater percentage of male patients was enrolled in Thailand (68%) than in Malawi (48%; p<0·001). 255 (74%) patients were HIV infected. 34 (10%) patients had M tuberculosis bacteraemia.
Clinical predictors of M tuberculosis bacteraemia in the combined study population included the presence of HIV
Discussion
Much current emphasis on controlling the global increase in tuberculosis is placed on promoting directly observed treatment, short course (DOTS). The main objective of this prevention effort, led by the WHO,1 is to achieve increased cure rates through greater compliance with antimicrobial therapy. This emphasis is appropriate given that both HIV-infected and non-infected patients may be rendered non-infectious for tuberculosis through treatment, and that the emergence of multidrug resistance in
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2019, HeliyonCitation Excerpt :In sub-Saharan Africa, many HIV positive individuals are co-infected with TB [2, 3]. In HIV-positive patients, TB is the leading cause of death [2], and many develop MTB bacteremia, sepsis and disseminated disease [4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], often dying within 30 days of hospitalization [10, 15]. Furthermore, strains of MTB are becoming increasingly resistant to antibiotic therapy, and the emergence of multiple drug resistant (MDR) and extensively drug resistant (XDR) strains have increased the urgency to find new approaches for prevention and treatment of TB [16].
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