Genetic variability of Mycobacterium tuberculosiscomplex in patients with no known risk factors for MDR-TB in the North-eastern part of Lima, Peru

Abstract

BackgroundThe aim of this study was to investigate the genetic diversity among Mycobacterium tuberculosis complex circulating in patients with no known risk factors for multi-drug resistant (MDR) tuberculosis (TB) living in a high MDR burden area and analyze the relationship between genotypes, primary drug resistance and age.MethodsSamples were collected during January-July 2009. Isolates were tested for drug susceptibility to first-line drugs and were genotyped by spoligotyping and the 15-loci Mycobacterial Interspersed Repetitive Unit (MIRU15).ResultsAmong the 199 isolates analyzed, 169 (84.9%) were identified in the SpolDB4.0 and 30 (15.1%) could not be matched to any lineage. The most prevalent lineage was Haarlem (29.6%), followed by T (15.6%), Beijing (14.1%), Latin American Mediterranean (12.6%) and U (8.5%). A few isolates belonged to the X and S clades (4.5%). Spoligotype analysis identified clustering among 148 of 169 isolates, whereas with MIRU15 all isolates were unique. Out of 197 strains; 31.5% were resistant to at least one drug, 7.5% were MDR and 22.3% showed any resistance to isoniazid.ConclusionIn contrast with other Latin-American countries where LAM lineage is the most predominant, we found the spoligotype 50 from the Haarlem lineage as the most common. None of the prevailing lineages showed a significant association with age or resistance to isoniazid and/or rifampicin.

Predominant Mycobacterium tuberculosis Families and High Rates of Recent Transmission among New Cases Are Not Associated with Primary Multidrug Resistance in Lima, Peru

“…Our results agree with this observation and previous Peruvian studies in which the Beijing family was present in relatively high proportions but was not associated with multidrug resistance (23,25,41,42). The prevailing Beijing isolates in Lima are associated with the modern subfamily coming from China, consistent with the worldwide trend except in the cases of Japan and Korea, where the ancient subfamily predominates.…”

“…Second, transmission could have occurred prior to our sampling period. When we compared our results with those of a previous study conducted in the same district in 2009 (42), however, we found few shared clusters between the two sets of samples; the 2009 study focused on low-MDR-risk patients, who did not represent the entire pool of MDR-TB cases in the area. Moreover, our study covered almost 2 years of sampling, which is considered the minimum time to study recent transmission (62).…”

“…With the exception of a study on MDR-TB household contacts, in which LAM was most frequent (41), this predominance of the Haarlem genotype has been observed in all Peruvian studies to date (23)(24)(25)42). Despite heterogeneity in the design and size of those studies, the combined data suggest a trend of increasing prevalence of the Haarlem genotype in Lima in the past decade, with an increase from 23.8% to 35.3% (23,25,41,42).…”

“…Despite heterogeneity in the design and size of those studies, the combined data suggest a trend of increasing prevalence of the Haarlem genotype in Lima in the past decade, with an increase from 23.8% to 35.3% (23,25,41,42). Among a selection of MDR-TB and XDR-TB isolates collected in Peru in 2007 to 2009, the prevalence reached 43.6% (24).…”

Description of the population structure and genetic diversity of tuberculosis in Estado de México, a low prevalence setting from Mexico

“…Compared with our findings, lineages LAM (15%), Haarlem (17%) and T (20%) fit within the expected ranks. However, the number of individuals (53 or 29%) found with a X lineage is one of the highest reported to date in Mexico, and far exceeds the values reported in some Central and South American countries, such as Honduras with 6% , Peru with 4.5% , Brazil with 4.7% and Colombia with 1.7% .…”