Primary drug resistance in HIV/TB patients

The aim of the study was to examine the frequency of MBT detection and the spectrum of primary drug resistance in HIV-positive patients with TB depending on the degree of immunosuppression. A study of 304 HIV-positive new TB cases registered during 2006-2010 with median CD4 count 140 cells/μl was carried out in TB Hospital #7 (Moscow, Russian Federation). The mean age was 31,6±6,4 years. Etiologic confirmation of TB was obtained in 56,9% of patients (n=173), including those from sputum (35,2%, n=107), and the rest (n=66) from other materials (exudate, urine, cerebrospinal fluid, discharge from the fistula, biopsy material). Patients with CD4+ 350 cells/μl were found to be smear and/or culture positive more frequently (42,7%, n=53 and 42,0%, n=18 respectively) than those with CD4+ 100-349 cells/μl (26,2%, n=36) (p<0,05). Drug susceptibility test was conducted in 126 patients on Lowenstein-Jensen media using absolute concentration method. MBT were susceptible in 48,4% of patients (n=61). 7,1% of isolates were monoresistant, polyresistance was found in 15,1% (n=19) (in most cases to combination of streptomycin or isoniazid – 57,9%). MDR TB was detected in 29,4% of patients (n=37) (including 4 cases of XDR, 3,2%). It should be noted that MDR was recorded in 35,4% of patients with CD4 + lymphocytes 200 cells/μl was 19,2% (9 out of 47) (p<0,05). Resistance to fluoroquinolones was registered in 7,1%. Conclusion: Primary MDR was detected in every 3rd HIV/TB patient. The results of the study suggest the frequency of MBT detection from sputum in HIV/TB patients, as well as frequency of MDR, depends on the degree of immunosuppression.