الفهرس 
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Abstract
The ability to discern the molecular “fingerprint” (genotype) of M. tuberculosis isolates has provided the means to identify and to track specific strains in tuberculosis infection. Pulsed-field gel electrophoresis (PFGE) is a powerful molecular biology technique which has been widely used to type various microorganisms in both outbreak and population-based studies. Although, the high discriminatory power and reproducibility of the PFGE in M. tuberculosis genolyping, few studies have used PFGE for the molecular epidemiology of M tuberculosis because this method remains laborious and time-consuming, especially when it is applied to mycobacteria. Little has been done to develop standardized methods for analyses of M. tuberculosis PFGE patterns. In this study, a molecular typing protocol based on PFGE was developed. To achieve to the optimal method of cell lysis and complete protein digestion, various protocols were tested using the Iv! tuberculosis reference strain HRv37 (ATCC# 25618). The protocol which succeeded to lyse M. tuberculosis reference strain HRv37 (ATCC# 25618) was standardized for Al. tuberculosis typing. The optimization results revealed that (i) the best medium to subcullured the bacteria is the 71-19 middlebrook with the addition of ampicillin and D—cycloserine, (ii) the optimal lysis of bacterial cell wall occurs within the fIrst 2 hours of incubation at 37°C and could proceed fbr up to overnight, (iii) the DNA extraction in plugs occurs