[Proposal of a five MIRU-VNTR panel to screen clinical isolates of Mycobacterium tuberculosis in Mexico]. / Propuesta de un panel MIRU-VNTR 5 para el tamizaje de aislamientos clínicos de Mycobacterium tuberculosis en México.

INTRODUCTION: Tuberculosis is a public health problem across Mexico. This paper aims to select a panel, with a minimum number of repetitive elements (MIRU-VNTR) for genotypic characterization of Mycobacterium tuberculosis (M. tuberculosis) clinical isolates. METHOD: In this study, a full panel of 24 MIRU-VNTR loci was used to discriminate 65 clinical isolates of M. tuberculosis from three different geographical regions of Mexico. Those loci with the highest discriminatory power were subsequently selected. RESULTS: The panel, including five loci, was obtained by selecting the highest values of allelic diversity among the genotypes obtained. The dendrogram, generated by the panel MIRU-VNTR 5, showed a high discriminatory power with 65 unique genotype profiles and formed clusters according to the geographical region of origin. CONCLUSIONS: The panel MIRU-VNTR 5 can be useful for characterizing clinical isolates of M. tuberculosis in Mexico.

Characterisation of pks15/1 in clinical isolates of Mycobacterium tuberculosis from Mexico.

Tuberculosis (TB) is an infectocontagious respiratory disease caused by members of the Mycobacterium tuberculosis complex. A 7 base pair (bp) deletion in the locus polyketide synthase (pks)15/1 is described as polymorphic among members of the M. tuberculosis complex, enabling the identification of Euro-American, Indo-Oceanic and Asian lineages. The aim of this study was to characterise this locus in TB isolates from Mexico. One hundred twenty clinical isolates were recovered from the states of Veracruz and Estado de Mexico. We determined the nucleotide sequence of a ± 400 bp fragment of the locus pks15/1, while genotypic characterisation was performed by spoligotyping. One hundred and fifty isolates contained the 7 bp deletion, while five had the wild type locus. Lineages X (22%), LAM (18%) and T (17%) were the most frequent; only three (2%) of the isolates were identified as Beijing and two (1%) EAI-Manila. The wild type pks15/1 locus was observed in all Asian lineage isolates tested. Our results confirm the utility of locus pks15/1 as a molecular marker for identifying Asian lineages of the M. tuberculosis complex. This marker could be of great value in the epidemiological surveillance of TB, especially in countries like Mexico, where the prevalence of such lineages is unknown.

Tuberculosis in Mexico and the USA, Comparison of Trends Over Time 1990-2010.

BACKGROUND: The aim was to compare tuberculosis trends in Mexico and United States and to evaluate Mexican diagnostic methods and contact investigation. METHODS: Retrospective comparative study of tuberculosis cases and incidence rates between both countries (1990-2010). Diagnostic methods and contact investigations were also evaluated for Mexico. Estimates were obtained from official websites. RESULTS: In Mexico, no clear trend was found over time for cases. Pulmonary (PTB) and all forms of tuberculosis (AFTB) incidence decreased 2.0% annually. There was a negative correlation between the mean contacts examined per case and AFTB incidence (r(2)=-0.44, p=0.01) with a 33% reduction in AFTB incidence. In United States, PTB and AFTB cases have been decreasing 6.0% and 5.6% annually, respectively. The incidence decreased 7.3% and 6.8%, respectively. CONCLUSION: The incidence of tuberculosis in Mexico is decreasing slightly over time at 2% annually. In the United States, cases and incidence rates have been decreasing at a higher rate (5% to 7% annually). The inverse association between number of contacts examined per state and incidence rates in Mexico underscore the importance of reinforcing and improving contact investigations with the likely translation of a decrease of TB incidence at a higher rate.

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

In order to identify the genetic characteristics of the strains of mycobacteria circulating in the Estado de México, one of the states with the lowest prevalence of tuberculosis in Mexico, spoligotyping and 12-loci MIRU-VNTR typing were used to genotype tuberculosis clinical isolates. The average age of the 183 patients analyzed was 50 (± 17) years, drug resistance was noted in 57 (31%) and multidrug resistance in 22 (12%) individuals. The results from the isolates recovered showed that 80% were located in four major Euro-American lineages: Haarlem (17%), LAM (15%), T (20%) and X (29%). Other lineages found in lower proportions were: EAI, S, Beijing, West African, Turkey, Vole and Bovis. Eighteen isolates were orphans. Only 57 isolates were grouped in nine clusters and the SIT119 (X1) showed the highest number of members (23). The LAM lineage showed an increased risk for development of drug resistance (RR=4, IC: 95%: 1.05-14.2, p = 0.03). Despite the important prevalence of four major lineages found and the diversity of strains circulating in the population, we found the presence of one of the largest populations of isolates clustered to the X lineage in a setting from a Latin American country.

Úlcera crónica por Mycobacterium chelonae: informe de dos casos y claves para el diagnóstico de micobacteriosis cutáneas / Chronic ulcer by Mycobacterium chelonae: a report of two cases and keys for the diagnosis of cutaneous mycobacteriosis

Resumen Se comunican dos casos clínicos poco frecuentes de micobacteriosis cutáneas; uno adquirido en la comunidad y uno en medio hospitalario, ambos pacientes del género masculino, con dermatosis crónicas constituidas por úlceras, fístulas y placas de aspecto papilomatoso. El diagnóstico fue tardío y la evolución no fue satisfactoria, a pesar de prescribir tratamiento adecuado contra Mycobacterium chelonae. El propósito de este artículo es mostrar la manifestación clínica de las lesiones para sospecha diagnóstica temprana y oportuna de las diferentes disciplinas médicas que participan en la atención de los pacientes con estas infecciones.

Abstract This paper reports the two rare clinical cases of cutaneous mycobacterial infections. One of them acquired the infection within the community while the other was a nosocomial case, both cases were male with chronic ulcers, fistulae and papilloma-like lesions. In both cases diagnosis was late and evolution, despite correct Mycobacterium chelonae treatment, was unsatisfactory. The purpose of this paper is to show the clinical presentation and accurate suspicion of infection of the different medical areas involved in its management.

Characterisation of pks15/1 in clinical isolates of Mycobacterium tuberculosis from Mexico

Tuberculosis (TB) is an infectocontagious respiratory disease caused by members of the Mycobacterium tuberculosis complex. A 7 base pair (bp) deletion in the locus polyketide synthase (pks)15/1 is described as polymorphic among members of the M. tuberculosis complex, enabling the identification of Euro-American, Indo-Oceanic and Asian lineages. The aim of this study was to characterise this locus in TB isolates from Mexico. One hundred twenty clinical isolates were recovered from the states of Veracruz and Estado de Mexico. We determined the nucleotide sequence of a ± 400 bp fragment of the locus pks15/1, while genotypic characterisation was performed by spoligotyping. One hundred and fifty isolates contained the 7 bp deletion, while five had the wild type locus. Lineages X (22%), LAM (18%) and T (17%) were the most frequent; only three (2%) of the isolates were identified as Beijing and two (1%) EAI-Manila. The wild type pks15/1 locus was observed in all Asian lineage isolates tested. Our results confirm the utility of locus pks15/1 as a molecular marker for identifying Asian lineages of the M. tuberculosis complex. This marker could be of great value in the epidemiological surveillance of TB, especially in countries like Mexico, where the prevalence of such lineages is unknown.