Mycobacterium tuberculosis spoligotypes circulating in the Syrian population: A retrospective study.

OBJECTIVES: To characterize by spoligotyping clinical isolates of Mycobacterium tuberculosis (MTB) collected between July 2003 and October 2005 from all Syrian provinces (muhafazat). METHODS: All isolates (n=96) were cultured and identified by biochemical characteristics. DNA extracts of these samples were amplified by PCR and genotyped by spoligotyping. RESULTS: Twelve patterns were identified: 46.8% of the strains belonged to T 1 family; 20.8% to LAM 9; 10.4% to CAS; 9.3% to Haarlem 3; 4.1% to Haarlem 1; 2.1% to Family 34; and 1% to each of Family 36, EAI 5, LAM 1, LAM 8, T 3, and X 3 families. The noticeable absence of the Beijing family was not consistent with the patterns reported in most neighboring countries. CONCLUSION: A more inclusive study of the Syrian population is necessary to more accurately identify most of the prevailing families in the country.

Genotypic detection of rifampicin-resistant M. tuberculosis strains in Syrian and Lebanese patients.

SETTING: The incidence of multi- and extensively drug-resistant TB cases is increasing in many countries. Resistance to rifampicin is widely considered a surrogate marker for multiple drug resistant TB. No efforts have been made to identify and quantify the drug-resistant genotypes in the Syrian and Lebanese communities. OBJECTIVE: The genotypic characterization of rpo B mutations in the rifampicin drug-resistance region (RRDR) of resistant Mycobacterium tuberculosis isolates in Syrian and Lebanese patients. DESIGN: The pyrosequencing technique was applied to DNA derived from the M. tuberculosis isolates of 56 patients. RESULTS: RRDR sequencing identified 97 modified codons representing 35 different mutations; 31 (34%) of the 97 modifications were novel and have not been previously reported. The changes were mostly within codons 531 (37/97: 38%), 533 (28/97: 29%) and 526 (9/97: 9%). Additionally, 30 (54%) isolates had multiple codon changes. CONCLUSION: This study indicates the importance of the RRDR hotspot region for the detection of rifampicin resistance in MTB clinical isolates from Syrian and Lebanese patients. However, new mutations and mutations in other locations within the RRDR were also observed. The vast majority (95%) of the studied isolates from this pool of patients contained mutations in codons 531 and/or 533.

Testing for the presence of Mycobacterium tuberculosis Beijing genotype strains in Syrian samples.

The Beijing family of Mycobacterium tuberculosis (MTB) has been reported to have an exceptional capacity to spread tuberculosis (TB) and induce multi-drug resistance. A method has been developed to distinguish this family from the rest of the MTB families through real-time DNA amplification and subsequent analysis of the melting point of an amplicon. Two pools of multi-drug resistant (MDR) MTB samples collected at two different time periods from various regions in Syria have been selected. This preliminary screening indicated a complete absence of the Beijing family in all samples. This research presents an effective differentiation of bacterial Beijing strains, with minimal effort and cost through analysis of differential amplicon melting points.