Objective: To describe the prevalence and epidemiological-clinical characteristics of tuberculosis (TB) resistance to first-line drugs in Italian human immunodeficiency virus (HIV)-infected subjects.
Design: Prospective, observational multicenter (25 Centers of Infectious Diseases) study. Mycobacterium tuberculosis strains from 167 HIV co-infected subjects with TB (149 new cases, 18 relapses) were tested at a central laboratory for susceptibility to rifampin (R), isoniazid (H), pyrazinamide (Z), ethambutol (E) and streptomycin (S) and for DNA fingerprint type. Drug susceptibility results were related to patients' epidemiological, clinical and laboratory features.
Results: Drug resistance patterns among new TB cases were as follows: R = 1%, Z = 6%, S = 8%, H + S = 3%, S + Z = 4%. TB resistant to at least R + H (MDR-TB) was detected in 36% of new cases due to an MDR-TB outbreak which was the largest thus far in Europe, involving 7/25 participating institutions, and was demonstrated by conventional and molecular epidemiology evidence. With multivariate analysis, MDR-TB was associated with hospital exposure to MDR-TB (OR = 39.3, P < 0.001) and previous use of anti-TB drugs (OR = 9.8, P = 0.008).
Conclusion: As drug-resistant tuberculosis in Italy is thus far relatively scarce, detection of a large MDR-TB epidemic among HIV-infected subjects was alarming. Aggressive control measures are urgently needed to prevent the spread of MDR-TB throughout the country and among the general population.