Unrecognised Mycobacterium tuberculosis bacteraemia among hospital inpatients in less developed countries

Nosocomial transmission of Mycobacterium tuberculosis is a global public-health concern. Although early clinical recognition of M. tuberculosis in hospital inpatients is critical for effective infection control, such recognition may be difficult in patients with HIV infection. To find out whether M. tuberculosis bacteraemia frequently goes unrecognised, we did a prospective blood-culture survey in an infectious-diseases hospital in Thailand and a general hospital in Malawi.

Consecutive febrile (> or = 37.5 degrees C axillary or > or = 38.0 degrees C orally) hospital inpatients (aged > or = 18 years) were enrolled; blood was obtained for mycobacterial culture and HIV testing. Simple diagnostic tests, such as chest radiographs and sputum smears, were ordered by clinicians as deemed necessary, and were carried out with existing local resources.

Of 344 patients enrolled, 255 (74%) were HIV infected, the median age was 33 years (range 18-87), and 208 (61%) were male. 34 (10%) patients had M. tuberculosis bacteraemia; five of these patients were already on antituberculosis therapy. Only HIV-infected patients had M. tuberculosis bacteraemia. Of the 29 patients with M. tuberculosis bacteraemia who were not already receiving antituberculosis therapy, 13 (45%) had an abnormal chest radiograph or a positive sputum smear. 16 (55%) patients had no additional diagnostic test results to indicate M. tuberculosis infection; 18 (81%) of these had a cough.

In less developed countries where both M. tuberculosis and HIV infections are prevalent, M. tuberculosis bacteraemia may frequently go unrecognised among febrile hospital inpatients.