Dataset Information

Molecular epidemiology of Mycobacterium tuberculosis complex in Singapore, 2006-2012.

ABSTRACT:

Background

Tuberculosis remains common in Singapore, increasing in incidence since 2008. We attempted to determine the molecular epidemiology of Mycobacterium tuberculosis complex (MTC) isolates locally, identifying major circulating genotypes and obtaining a glimpse of transmission dynamics.

Methodology

Non-duplicate MTC isolates archived between 2006 and 2012 at the larger clinical tuberculosis laboratory in Singapore were sampled for spoligotyping and MIRU-VNTR typing, with case data obtained from the Singapore Tuberculosis Elimination Program registry database. Isolates between 2008 and 2012 were selected because of either multidrug-resistance or potential epidemiological linkage, whereas earlier isolates were randomly selected. Separate analyses were performed for the early (2006-2007) and later (2008-2012) study phases in view of potential selection bias.

Principal findings

A total of 1,612 MTC isolates were typed, constituting 13.1% of all culture-positive tuberculosis cases during this period. Multidrug-resistance was present in 91 (5.6%) isolates - higher than the national prevalence in view of selection bias. The majority of isolates belonged to the Beijing (45.8%) and EAI (22.8%) lineages. There were 347 (30.7%) and 133 (27.5%) cases clustered by combined spoligotyping and MIRU-VNTR typing from the earlier and later phases respectively. Patients within these clusters tended to be of Chinese ethnicity, Singapore resident, and have isolates belonging to the Beijing lineage. A review of prior contact investigation results for all patients with clustered isolates failed to reveal epidemiological links for the majority, suggesting either unknown transmission networks or inadequate specificity of the molecular typing methods in a country with a moderate incidence of tuberculosis.

Conclusion

Our work demonstrates that Singapore has a large and heterogeneous distribution of MTC strains, and with possible cross-transmission over the past few years based on our molecular typing results. A universal MTC typing program coupled with enhanced contact investigations may be useful in further understanding the transmission dynamics of tuberculosis locally.

SUBMITTER: Lim LK

PROVIDER: S-EPMC3867517 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Molecular epidemiology of Mycobacterium tuberculosis complex in Singapore, 2006-2012.

Lim Leo Kang-Yang LK Sng Li Hwei LH Win Wah W Chee Cynthia Bin-Eng CB Hsu Li Yang LY Mak Estelle E Earnest Arul A Ong Marcus Eng-Hock ME Cutter Jeffery J Wang Yee Tang YT

PloS one 20131218 12

<h4>Background</h4>Tuberculosis remains common in Singapore, increasing in incidence since 2008. We attempted to determine the molecular epidemiology of Mycobacterium tuberculosis complex (MTC) isolates locally, identifying major circulating genotypes and obtaining a glimpse of transmission dynamics.<h4>Methodology</h4>Non-duplicate MTC isolates archived between 2006 and 2012 at the larger clinical tuberculosis laboratory in Singapore were sampled for spoligotyping and MIRU-VNTR typing, with cas ...[more]

PMID: 24367667

Similar Datasets

Project description:BackgroundThe control of tuberculosis in densely populated cities is complicated by close human-to-human contacts and potential transmission of pathogens from multiple sources. We conducted a molecular epidemiologic analysis of 356 Mycobacterium tuberculosis (MTB) isolates from patients presenting pulmonary tuberculosis in metropolitan Taipei. Classical antibiogram studies and genetic characterization, using mycobacterial interspersed repetitive-unit-variable-number tandem-repeat (MIRU-VNTR) typing and spoligotyping, were applied after culture.MethodsA total of 356 isolates were genotyped by standard spoligotyping and the strains were compared with in the international spoligotyping database (SpolDB4). All isolates were also categorized using the 15 loci MIRU-VNTR typing method and combin with NTF locus and RD deletion analyses.ResultsOf 356 isolates spoligotyped, 290 (81.4%) displayed known spoligotypes and 66 were not identified in the database. Major spoligotypes found were Beijing lineages (52.5%), followed by Haarlem lineages (13.5%) and EAI plus EAI-like lineages (11%). When MIRU-VNTR was employed, 140 patterns were identified, including 36 clusters by 252 isolates and 104 unique patterns, and the largest cluster comprised 95 isolates from the Beijing family. The combination of spoligotyping and MIRU-VNTR revealed that 236 (67%) of the 356 isolates were clustered in 43 genotypes. Strains of the Beijing family was more likely to be of modern strain and a higher percentage of multiple drug resistance than other families combined (P = 0.08). Patients infected with Beijing strains were younger than those with other strains (mean 58.7 vs. 64.2, p = 0.02). Moreover, 85.3% of infected persons younger than 25 years had Beijing modern strain, suggesting a possible recent spread in the young population by this family of TB strain in Taipei.ConclusionOur data on MTB genotype in Taipei suggest that MTB infection has not been optimally controlled. Control efforts should be reinforced in view of the high prevalence of the Beijing strain in young population and association with drug resistance.

Project description:BackgroundTuberculosis (TB) and drug-resistant TB (DR-TB) continue to persist as a serious public health challenges in Ghana. Although several research has evaluated the drug resistance of Mycobacterium tuberculosis complex (MTBc) strains across the country, there is a paucity of data on its magnitude as well as the various lineages circulating in the Eastern region of Ghana.ObjectiveThis study therefore evaluated the distribution of the various lineages of MTBc in the Eastern region of the country and the associated drug resistance.Materials and methodsOne hundred and forty-three (143) patients with pulmonary TB attending the Eastern Regional Hospital, Koforidua/Ghana were included in the study. The BACTEC MGIT 960 tube media was used for both sputum culture and drug susceptibility of streptomycin (STR), isoniazid (INH), rifampicin (RIF) and Ethambutol (ETH). Isolates were initially typed using IS6110, followed by large sequence polymorphisms analysis and spoligotyping.ResultsThe majority [108 (75.5%)] of the 143 patients were male gender and the 45-54 years [46 (32.2%)] age range had the highest frequency. Forty-one (28.7%) of the 143 isolates were IS6110 negative. Of the 102 spoligotyped isolates, the main sub-lineages included 45 (44.1%) Cameroon and 23 (22.5%) Ghana. SITs 61 and 53 represented the major cluster with 22/102 (21.6%) and 13/102 (12.7%) isolates respectively, while 59/65 (90.8%) isolates belonged to Lineage 4 with 27/65 (41.5%) LAM10_CAM. MDR-TB occurred in 26/79 (32.9%) isolates, and was not associated with neither gender [20/58 (34.5%) male vs 6/21 (28.6%) female, OR = 1.31; 95%CI, 0.44-3.92; p = 0.624)] nor age. No association was found between MDR-TB and the major sub-lineages [8/25 (32%) Cameroon (OR = 0.94; 95%CI, 0.34-2.59; p = 0.920) and 5/11 (45.5%) Ghana (OR = 1.87; 95%CI, 0.51-6.80; p = 0.489)], or previously treated [8/23 (34.8%), OR = 0.89; 95%CI, 0.32-2.48; p = 0.823)] patients.ConclusionDespite the serious threat posed by MDR in the study area, no sub-lineage was shown to be associated with drug resistance. Nonetheless, a sustained surveillance of drug resistance pattern is advocated. A lower proportion of M. africanum was observed in the Eastern region of Ghana and will require further evaluation.

Dataset Information

Molecular epidemiology of Mycobacterium tuberculosis complex in Singapore, 2006-2012.

Background

Methodology

Principal findings

Conclusion

Publications

Molecular epidemiology of Mycobacterium tuberculosis complex in Singapore, 2006-2012.

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