〔目的〕国内の結核低蔓延地域において結核菌VNTR分析を広範に実施し，低蔓延下の結核対策における同分析の有用性を明らかにする。〔方法〕2009～2011年に山形県内で新規登録された菌陽性肺結核患者266人中184人（69.2%）から分離された結核菌の24領域VNTR分析を実施した。VNTRパターンが23領域以上一致した菌株を同一クラスタと定義し，各クラスタの由来患者間の関連性の有無を実地疫学調査結果から検証した。〔結果〕184株中49株（26.6%）が17クラスタを形成した。関連性がある事例として，6クラスタ内に院内感染3事例，家族内感染3事例，施設内感染1事例を見出した。このうち，院内感染，施設内感染各1事例ではVNTR分析により未知の伝播が明らかにされた。最大クラスタ（12株）のVNTRパターンは，2007年発端の集団感染事例の初発患者パターンと一致した。〔考察〕結核低蔓延地域では，広く収集した患者由来菌株のVNTR分析と実地疫学調査の結果を組み合わせることで，未知の感染伝播の発見，新たな感染リスク集団の探知，および集団感染の追跡に役立つなど，VNTR分析の高い有用性が確認された。

[Background] The Philippines is designated as one of the high tuberculosis (TB) burden countries by WHO. We conducted a molecular epidemiologic analysis of Mycobacterium tuberculosis isolates collected from patients consulting at the health clinics in the city of Santa Rosa, Laguna, a suburban community in the Philippines. [Methods] A total of 116 M.tuberculosis isolates were characterized and genotyped using spoligotyping and 15 loci of variable number of tandem repeats of mycobacterial interspersed repetitive units (15 MIRU-VNTR). The strains were then compared with the international spoligotyping database (SpolDB4). Cluster analyses were done using 15 MIRU-VNTR and spoligotyping. [Results] Majority of the patients with pulmonary tuberculosis were young (18_29 year age group at 41.4％) and male (62.1％). 86/116 (74.1％) were sputum-smear positive and 43/116 (37.1％) had severe pulmonary tuberculosis. When the genotyping results were compared to the SpolDB4, there were 10 identified Spoligo-International-Types (SITs) with SIT19 as the predominant SIT (89/116, 76.7％). 10 out of 116 (8.6％) did not match any SIT in the SpolDB4. The distribution of strains according to major M.tuberculosis clades was as follows: EAI2_Manilla (101/116, 87.1％; U 2/116, 1.7％; LAM2 1/116, 0.9％; EAI3_Ind 1/116, 0.9％; MANU2 1/116, 0.9％. Using univariate and multivariate analysis, there was no significant association shown between the EAI2_Manilla clade and SIT with patient characteristics such as sex and age groups as well as bacillary load based on sputum-smear positivity and severity of pulmonary tuberculosis. Using logistic regression, no patient characteristic, as well as bacillary load or severity of TB, were significant predictors for clade or SIT. Based on the molecular typing method used, spoligotyping identified 4 clusters and 20 genotypes (16 unique strains) with a Hunter-Gaston discrimination index (HGDI) of 0.409. 15 MIRU-VNTR identified 16 clusters and 69 genotypes (53 unique strains) with an HGDI of 0.960. The combination of spoligotyping and 15 MIRU-VNTR identified 11 clusters and 79 genotypes (68 unique strains) with the highest HGDI at 0.970. High case rate of TB among young people in this community suggests the high transmission rate of infection. However, in the absence of significant association between clustering and age, the interpretation of observed high cluster rate warrants caution, and requires further molecular and epidemiological observation. [Conclusion] This is the first molecular epidemiology study to show the distribution of genotypes of the M.tuberculosis strains, systematically and prospectively sampled, of the patient population in a suburban community in the Philippines. The combination of spoligotyping and 15 MIRU-VNTR identified 11 clusters and 79 genotypes (68 unique strains) with the highest HGDI at 0.970. High case rate of TB among young people in this community suggests the high transmission of infection. However, in the absence of significant association between clustering and age, the interpretation of observed high cluster rate warrants caution, and requires further molecular and epidemiological observation.