Abstract
BackgroundGrowing evidences suggested that the Mycobacterium tuberculosis complex (MTBC) lineages can determine the clinical outcome of pulmonary and extra-pulmonary tuberculosis. However, limited data only available revealing such association of bacterial genotypes and clinical phenotypes from immigrant rich countries.MethodsA multicenter study has been carried out on a collection of 2092 (1003 extrapulmonary and 1089 pulmonary) MTBC isolates. Genotyping of all the isolates were carried out by spoligotyping and 24 loci based MIRU-VNTR typing.ResultsDemographically domination of young Saudi nationals (61.4%) and men (61.2%) were found in this cohort. Lymph nodes (62.4%) and gastrointestinal sites (16.7%) were the most common anatomical sites of infection. The predominant lineages were Delhi/CAS (26.9%), EAI (14.2%) and Ghana (9.9%). Mycobacterium africanum type I and II were reported for the first time in the country among extrapulmonary cases. ‘Ancestral’ lineages M.bovis (OR-5.22; 95% CI-2.23-8.22, p- < 0.001) and Delhi/CAS (OR-0.57; 95% CI-0.411-0.734, p- < 0.001) were directly associated with lymph node tuberculosis and gastrointestinal tuberculosis (M. bovis-OR-0.33; 95% CI-0.085-0.567, p-0.001 and Delhi/CAS-OR-1.87; 95% CI-1.22-2.53, p- < 0.001) respectively. Among the ‘Modern’ lineages, EAI showed significant association to central nervous system tuberculosis (OR-1.98; 95% CI-0.76-3.19, p-0.04) and Uganda-I to gastrointestinal tuberculosis (OR-2.41; 95% CI-0.77-4.06, p-0.02).ConclusionsThe findings substantially contribute to the emerging evidences that MTBC lineages influence disease phenotypes and epidemiological consequences.
Highlights
Growing evidences suggested that the Mycobacterium tuberculosis complex (MTBC) lineages can determine the clinical outcome of pulmonary and extra-pulmonary tuberculosis
The age group below 14 years showed a statistically significant predominance of Extrapulmonary TB (EPTB) (P value < 0.0001).On the other hand, pulmonary TB (PTB) incidence was more significant among the age group 15–29 and 49–59
76.6% of EPTB cases were found with an age below 45 years
Summary
Growing evidences suggested that the Mycobacterium tuberculosis complex (MTBC) lineages can determine the clinical outcome of pulmonary and extra-pulmonary tuberculosis. Several previous studies revealed conflicting evidences on the association of MTBC phylogenetic lineages and site of infection [6, 7]. Such analysis was scarce from the Middle Eastern countries including Saudi Arabia. Annually the country receives 10 million pilgrims to the Islamic holy cities This population diversity was reflected highly on the spectrum of MTBC lineages in the country, with the presence of almost all defined lineages including indigenous strains [8,9,10]. A recent study reported the lineage spectrum of MTBC in PTB and EPTB cases in the country, no detailed systematic analysis was carried out to date [8]. For the first time in the country a multicenter study on a large cohort of pulmonary and extrapulmonary TB cases has been carried out to analyze the impact of MTBC lineages towards disease phenotypes
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