ABSTRACT
I. Introduction The emergence of resistance to antimicrobials is a natural biological occurrence and a response to the selective pressure of the drug. The introduction of every antimicrobial agent into clinical practice for the treatment of infectious diseases in humans and animals has been eventually followed by the detection of isolates of resistant microorganisms, that is, microorganisms able to multiply in the presence of drug concentrations found in hosts receiving therapeutic doses (1). With increasing use and misuse of antibiotics, resistance has emerged in many microorganisms including Mycobacterium tuberculosis (2-6). The emergence of drug-resistant M. tuberculosis has been associated with a variety of provider, patient, and management factors including poor adherence to treatment (7-9), inappropriate prescription (10,11), irregular drug supply, or poor drug quality (12).
