Antituberculosis drug resistance in isolates of Mycobacterium tuberculosis complex in southeast Spain

Objectives The aim of this study was to determine resistance to antituberculosis (anti-TB) drugs in Mycobacterium tuberculosis complex isolates from patients diagnosed with Tuberculosis (TB) in southeast Spain and to study related epidemiological factors. Methods This retrospective study analysed 5-year data (2012-2016) obtained in southeast Spain for a total equivalent population of 1 735 608 inhabitants. Clinical samples were examined from 557 patients with suspected pulmonary TB (n=470; 84.4%) or extrapulmonary TB (n=87; 15.6%), taking into account patient age, sex, human immunodeficiency virus (HIV) infection, country of birth and prior anti-TB treatment. Results TB was found more frequently in men than in women (66.6% vs. 33.4%), and the age group with the most cases (43.7%) was 36-55 years. Among the first-line anti-TB drugs, 7.0% of patients harboured isolates resistant to isoniazid (INH) and 1.6% to rifampicin (RIF); moreover, 1.4% of isolates were multidrug-resistant TB (MDR-TB) and 0.7% were extensively drug-resistant TB. There was a statistically significant relationship (P=0.028) between MDR-TB isolates and non-Spanish-born patients, but not between the latter and INH resistance. Conclusion Resistance to INH and RIF was observed at levels similar to those published nationwide, with rates of MDR-TB being somewhat lower. Rates of HIV/TB co-infection have decreased considerably between 2012 and 2016.