Extensively drug-resistant tuberculosis (XDR-TB) in Argentina

RITACCO V; LÓPEZ B; MONTESERIN J; NATIONAL TB LABORATORY NETWORK; IMAZ S; BARRERA L

Brasov

Congreso; 33st Annual Congress European Society of Mycobacteriology; 2012

European Society for Mycobacteriology (ESM)

Transmission of the so-called strain M has been driving multidrug-resistant (MDR) TB trends in Argentina for almost 2 decades. In 2002, the strain M was isolated from the first 2 patients with XDR-TB ever diagnosed in the country. It was not until 2003, however, that the National TB Laboratory Network launched a systematic register of all incident MDR- and XDR-TB cases. Herein we analyze the characteristics of the 60 patients with XDR-TB diagnosed countrywide in 2003-2010, in the light of strain genotyping (IS6110 and spoligotyping). The man/woman ratio in the period was 1.2; the median age was 35 years (SD 11, range 17-72); 59 patients were born in South America (Argentina 33, Peru 6, Bolivia 4, Paraguay 1, Brazil 1, undetermined 14), and 1 was born in Indonesia; HIV infection was present in 16 (27%) patients, and disease localization was pulmonary in 57 (95%). The Asian-born patient and 1 Peruvian immigrant harbored the only 2 Beijing strains in the study. The strain M (lineage H2 SIT2) affected 23 (39%) patients, including 5/12 immigrants from other South American countries. All 23 patients in cluster M and 12/37 patients with other genotypes lived in Buenos Aires. The second largest cluster (lineage LAM5 SIT93) consisted in 10 patients involved in an XDR-TB outbreak occurred in Salta, a North Western province. Except for the place of residence, no significant differences in demographic/clinical features were found between patients in cluster M and patients affected by all other genotypes. Cases due to the strain M appeared to decrease within the period in favor of newly emergent genotypes but absolute numbers were too small to reveal temporal trends (chi square for trend p=0.13). In conclusion, the heaviest burden of XDR-TB is located in Buenos Aires, and an important fraction of it consists in the aftermath of the long-dated MDR-TB epidemic caused by the strain M. The national TB programme has recently implemented or reinforced sensible policies for MDR/XDR management and hospital infection control, which are expected to impact on the situation of these severe forms of TB in the country. Work financially supported by project PICT 2323/07, FonCyT, Argentina.