Tuberculosis Transmission among Immigrants and Autochthonous Populations of the Eastern Province of Saudi Arabia

Abstract

BackgroundEastern province of Saudi Arabia is an industrial zone with large immigrant population and high level of tuberculosis case notification among immigrants. The impact of immigration and current trends of tuberculosis transmission among immigrants and autochthonous population in the region had not been investigated so far using molecular tools.MethodologyDuring 2009- 2011, a total of 524 Mycobacterium tuberculosis isolates were collected from the central tuberculosis reference laboratory, representing an estimated 79.2% of the culture-positive tuberculosis cases over the study period in the province. These isolates were genotyped by using 24 locus-based MIRU-VNTR typing and spoligotyping followed by first line drug susceptibility testing. The molecular clustering profiles and phylogenetic diversity of isolates were determined and compared to the geographical origins of the patients.Principle FindingsGenotyping showed an overall predominance of Delhi/CAS (29.4%), EAI (23.8%) and Ghana (13.3%) lineages, with slightly higher proportions of Delhi/CAS among autochthonous population (33.3 %) and EAI (30.9%) among immigrants. Rate of any drug resistance was 20.2% with 2.5% of multi-drug resistance. Strain cluster analysis indicated 42 clusters comprising 210 isolates, resulting in a calculated recent transmission index of 32.1%. Overall shared cluster ratio was 78.6% while 75.8% were shared between autochthonous population and immigrant population with a predominance of immigrants from South east Asia (40.7%). In contrast, cross national transmission within the immigrant population was limited (24.2%). Younger age (15-30- p value-0.043, 16-45, p value 0.030), Saudi nationality (p value-0.004) and South East Asian origin (p value-0.011) were identified as significant predisposing factors for molecular strain clustering.ConclusionsThe high proportion of molecular clusters shared among the autochthonous and immigrant populations suggests a high permeability of tuberculosis transmission between both populations in the province. These results prompt for the need to strengthen the current tuberculosis control strategies and surveillance programs.

Mycobacterium tuberculosis complex: Detection and patterns of resistance to the first line anti-TB drugs at the King Abdulaziz University Hospital, Saudi Arabia

“…Our result matched also with that of Varghese et al [34] who reported no significant differences of drug-resistance rate between immigrants and local population in Saudi Arabia. Therefore, screening of expatriate workers and illegal immigrants into the Kingdom might help to control spread of TB infection.…”

“…Therefore, screening of expatriate workers and illegal immigrants into the Kingdom might help to control spread of TB infection. The Ministry of Health of the KSA has implemented such a plan and its effects will be evaluated over the next few years [34].…”

Tuberculosis in Saudi Arabia: the journey across time

“…In contrast, cross-national transmission among the immigrant groups was very limited (24.2%). This study concluded that the socio-economical characteristics of the migrant group have a distinctive and detectable impact on the diversity of strain lineages and transmission dynamics of TB in the eastern province of Saudi Arabia [6].…”

“…Varghese et al recently reported on the transmission of TB among the autochthonous and immigrant populations of the eastern province in Saudi Arabia, which has a large population of migrants [6].The recent transmission index in the region was 32.1%. Of particular interest was the observation that 75.8% of the strain clusters were shared between indigenous and immigrant populations, particularly immigrants from Southeast Asia (40.7%).…”

“…Regional differences in the incidence rate of TB in the country have been clearly demonstrated in several studies [5][6][7][8]. Some regions showed a decrease in TB prevalence, whereas other regions with a high number of immigrants showed an increase in TB incidence [9].…”