title: A first insight on the population structure of Mycobacterium tuberculosis complex as studied by spoligotyping and MIRU-VNTRs in Santiago, Chile.
abstract: Tuberculosis (TB) remains a significant public health problem worldwide, but the ecology of the prevalent mycobacterial strains, and their transmission, can vary depending on country and region. Chile is a country with low incidence of TB, that has a geographically isolated location in relation to the rest of South American countries due to the Andes Mountains, but recent migration from neighboring countries has changed this situation. We aimed to assess the genotypic diversity of Mycobacterium tuberculosis complex (MTBC) strains in Santiago, Chile, and compare with reports from other Latin-American countries. We analyzed MTBC isolates from pulmonary tuberculosis cases collected between years 2008 and 2013 in Central Santiago, using two genotyping methods: spoligotyping and 12-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTRs). Data obtained were analyzed and compared to the SITVIT2 database. Mean age of the patients was 47.5 years and 61% were male; 11.6% were migrants. Of 103 strains (1 isolate/patient) included, there were 56 distinct spoligotype patterns. Of these, 16 strains (15.5%) corresponded to orphan strains in the SITVIT2 database, not previously reported. Latin American and Mediterranean (LAM) (34%) and T (33%) lineages were the most prevalent strains, followed by Haarlem lineage (16.5%). Beijing family was scarcely represented with only two cases (1.9%), one of them isolated from a Peruvian migrant. The most frequent clustered spoligotypes were SIT33/LAM3 (10.7%), SIT53/T1 (8.7%), SIT50/H3 (7.8%), and SIT37/T3 (6.8%). We conclude that LAM and T genotypes are the most prevalent genotypes of MTBC in Santiago, Chile, and together correspond to almost two thirds of analyzed strains, which is similar to strain distribution reported from other countries of Latin America. Nevertheless, the high proportion of SIT37/T3, which was rarely found in other Latin American countries, may underline a specific history or demographics of Chile related to probable human migrations and evolutions.
authors: Infectious Diseases Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors: María Elvira
authors: ME
authors: Balcells
authors: Microbiology Laboratory, Clinical Laboratory Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors: Patricia
authors: P
authors: García
authors: Microbiology Laboratory, Clinical Laboratory Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors: Paulina
authors: P
authors: Meza
authors: Respiratory Division and Microbiology Laboratory, Hospital San Borja Arriarán, Santiago, Chile.
authors: Carlos
authors: C
authors: Peña
authors: Respiratory Division and Microbiology Laboratory, Hospital San Borja Arriarán, Santiago, Chile.
authors: Marcela
authors: M
authors: Cifuentes
authors: WHO Supranational TB Reference Laboratory, Institut Pasteur de la Guadeloupe, Abymes, Guadeloupe, France.
authors: David
authors: D
authors: Couvin
authors: WHO Supranational TB Reference Laboratory, Institut Pasteur de la Guadeloupe, Abymes, Guadeloupe, France.
authors: Nalin
authors: N
authors: Rastogi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D002677:Chile / Q000453:epidemiology; D005260:Female; D014644:Genetic Variation; D060005:Genotyping Techniques; D006801:Humans; D020071:Interspersed Repetitive Sequences / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D018598:Minisatellite Repeats / Q000235:genetics*; D017720:Molecular Epidemiology; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology; D055815:Young Adult