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Objective: Characterising clinical Mycobacterium tuberculosis isolates obtained from 1995 to 2006 in Bogotá , Colombia , using standardised IS6110-based RFLP typing for determining phylogenetic relationships. Calculating cases due to recent infection (grouped cases) cf endogenous reactivation (single patterns)., Methods: This retrospective study characterised 137 clinical Mycobacterium tuberculosis isolates obtained in Bogotá from 1995 to 2006. Study variables consisted of gender, age, HIV status, homelessness, Ziehl Neelsen smear result and date of culture. All isolates were freshly identified by phenotypic methods, confirmed by PRA and evaluated for susceptibility to antimicrobial agents according to the proportional method. Mycobacterium tuberculosis cultures were typed by standardised IS6110-based RFLP., Results: All isolates were confirmed as being M. tuberculosis by phenotypic and genotypic methods. 9,4 % monoresistance and 2,9 % MDR (rifampicin- and isoniazid-resistant) were found. 129 M . tuberculosis isolates were genotyped; 96 (74 %) of them presented unique DNA fingerprints, whilst 35 (26 %) were grouped into 17 clusters consisting of two to four isolates. Direct epidemiological links between patients could not be established in most cases. Only HIV status was a significant predictor of clustering amongst the variables being studied (p<0.05)., Conclusion: The results of our study revealed a high proportion of unique DNA fingerprints, suggesting high genetic variability between M. tuberculosis strains in Bogotá , Colombia , meaning that most cases of TB in this study were attributed to endogenous reactivation.

Objective: Evaluating the frequency of mycobacterium infection in an HIV-positive population and its influence on medium-term survival, along with clinical and epidemiological factors associated with co-infection., Methods: Several clinical specimens were studied for mycobacteria in a sample of 92 HIV+ patients at the San Juan de Dios teaching-hospital in Bogota, Colombia, during 1996. Factors associated with infection were measured using a prevalence ratio (PR), CI=95%, and logistic regression was used in the multivariable models. The likelihood of survival for three months was measured using Kaplan-Meir curves and factors associated with survival were assessed using Rate ratios and Cox's model., Results: Eight percent of the patients had tuberculosis and 6% of them were found to be infected with atypical mycobacterium. Mycobacterium avium complex (MAC) was the most frequent species, followed by M. fortuitum and M. chelonae. Mixed infections with M. tuberculosis and MAC were diagnosed in one patient and two different species of atypical mycobacterium were isolated in other two cases. Patients suffering from tuberculosis and stages III or IV HIV infection had a 16% survival rate., Conclusions: Tuberculosis-HIV/AIDS frequency and atypical Mycobacterium-HIV/AIDS' association were very similar. The most frequently isolated atypical mycobacterium specie in this study was MAC. Survival rate was lower for patients infected by M. tuberculosis and even lower when a multi-resistant strain was involved. The most important clinical factor associated with M. tuberculosis was the presence of fever and loss of weight with mycobacterial infection. Blood provided the best samples for isolating mycobacteria.