Characterization of mycobacteremia patients in a Fourth-Level Hospital in Medellín between 2018 and 2024.

Abstract

Background: Mycobacteremia, a serious manifestation of disseminated tuberculosis (TB) and other mycobacterial infections, occurs frequently in immunocompromised patients. It is marked by a typically delayed diagnosis and substantial mortality. Aims: To describe the clinical, epidemiological, and microbiological characteristics of adult patients with mycobacteremia and to identify factors related to timely diagnosis and clinical outcomes. Patients and Methods: A retrospective observational study of a cohort of adult patients with blood cultures positive for mycobacteria at a tertiary-care hospital in Medellín, Colombia, between January 2018 and December 2024. Clinical, sociodemographic, and laboratory variables, along with outcomes, were analyzed. Results: Of 1,315 blood cultures, 89 (6.7%) were positive for Mycobacterium spp.; 82% were M. tuberculosis. 61.8% of the patients had HIV infection with severe immunosuppression (median CD4 count: 29 cells/µL). The most common presentation was pulmonary TB (67.4%). In-hospital mortality was 18%; 51.7% required ICU care, and 38.2% required mechanical ventilation. 15.7% did not receive tuberculosis treatment due to a delayed diagnosis or transfer. Conclusion: Mycobacteremia carries a high rate of morbidity and mortality, particularly in immunocompromised individuals. Its characterization reinforces clinical suspicion and underscores blood culture as a diagnostic tool and prognostic marker to guide prompt therapeutic decisions.