Risk factors for multidrug-resistant bacterial infection among patients with tuberculosis

Given that anti-tuberculosis medication itself has antibacterial activity and that broad-spectrum antibiotics are frequently used, the emergence of multidrug-resistant (MDR) bacteria among patients being treated for tuberculosis (TB) is likely. We used a case-control design to study the clinical predictors of MDR bacterial infection among TB patients. Both cases and controls were selected from among patients who were diagnosed and treated as having TB between 1 January 1996 and 31 August 2006. TB patients with MDR bacterial infection were included as cases and those with non-MDR bacterial infection were included as controls. Multiple logistic regression analysis was performed to elucidate the risk factors for MDR bacterial infection. During the study period 3667 patients were diagnosed with, and treated for, TB. A total of 123 experienced episodes of bacterial infection, of whom 59 (48.0%) were infected by an MDR strain at least once. The presence of chronic renal failure [adjusted odds ratio (OR): 4.96; 95% confidence interval (CI): 1.37-18.01] and the use of antimicrobials other than typical anti-TB drugs within three months (adjusted OR: 4.37; 95% CI: 1.74-10.95) were independent risk factors for MDR bacterial infection. Bacterial infection in TB patients is commonly multidrug resistant. Clinicians should be aware of the possibility of MDR bacterial infection among TB patients with chronic renal failure or recent use of other antimicrobials.