Occurrence of RD149 and RD152 deletions in Mycobacterium tuberculosis strains from Pakistan
Introduction: Central Asian Strain 1 (CAS1) is the predominant Mycobacterium tuberculosis genotype in Pakistan. The occurrence of deletions in regions of differences (RDs) among CAS1 and other predominant genogroups in the country were investigated.
Methodology: Using stratified random sampling, 235 M. tuberculosis (185 pulmonary; 50 extrapulmonary) strains were selected from 926 previously spoligotyped isolates, including 171 CAS strains (133 CAS1 (ST26), 38 CAS subfamily), 8 Beijing isolates, 47 isolates belonging to other previously defined ("Other") clusters, and 9 previously undefined Unique isolates. Commonly reported RD deletions, RD1, RD750, RD207, RD149, RD152, RD105, RD150, RD142 and RD181, were investigated using a PCR-based method.
Results: Deletions in RDs 750, 149 and 152 were identified among CAS strains, and in RDs 207, 149, 152, 105, 150, 142 and 181 in Beijing isolates. CAS1 strains showed more frequent RD149 deletions compared with CAS subfamily strains (p=0.036), and more frequent RD152 deletions compared with "Other" clusters (p=0.003). RD149 and RD152 deletions were more frequent in Beijing isolates compared with CAS1 strains (p < 0.001). Concurrent RD149 and RD152 deletions were more frequent in CAS1 compared with "Other" clusters (p < 0.001) and in Beijing strains compared with CAS1 (p < 0.001). No significant difference was detected in RD deletion patterns between pulmonary and extra pulmonary isolates.
Conclusion: Higher frequencies of RD149 and RD152 deletions and of concurrent RD149 and RD152 deletions were found in CAS1 and Beijing strains compared with CAS subfamilies, "Other" clusters and Unique strains. No association between these deletions and disease presentation, pulmonary or extrapulmonary tuberculosis, was observed.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License that allows others to share the work with an acknowledgement of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgement of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).