The peculiarities of drug susceptibility of M. tuberculosis isolated from patients with late-stage HIV infection

<b>Introduction:</b> Fast spread of HIV infection makes the prognosis of HIV/TB co-infection unfavourable. Therefore, it is important to establish the etiological factor for TB verification, drug resistance determination, and commencement of adequate TB treatment. <b>Aim:</b> To characterize drug susceptibility of M. tuberculosis strains isolated from patients with late-stage HIV infection. <b>Materials and Methods:</b> We studied cultures isolated from 63 patients with late-stage HIV infection associated with newly diagnosed TB. There were 42 men and 21 women aged 18-62 yrs. We performed clinical, laboratory, X-ray and microbiology studies; the latter included luminescent microscopy, inoculation onto solid and liquid media, PCR for M. tuberculosis DNA detection. Phenotypic drug susceptibility testing involved the absolute concentrations method. <b>Results:</b> We discovered that 11/63 (17.5%) strains were sensitive, and 52/63 (82.8%) strains were resistant to TB drugs. We established monoresistance in 6/63 (9.5%), polyresistance in 7/63 (11.1%) strains. The largest number of strains were MDR, XDR or pre-XDR – 18/63 (28.6%), 7/63 (11.1%), 14/63 (22.2%) respectively. <b>Conclusions:</b> Patients with late-stage HIV infection associated with newly diagnosed TB are predominantly infected with drug resistant M. tuberculosis (82.8%). The severest TB forms, which are extremely difficult to treat, are MDR, pre-XDR, and XDR TB.