Analysis of Rocky Mountain spotted fever cases in Northern Mexico reveals genetic variability of Rickettsia rickettsii and the different distribution of genotypes.

Rickettsioses have been reported in parts of Mexico since the last century, with Rocky Mountain spotted fever (RMSF) being one of the most prevalent in northern states. Unfortunately, fatality rates for RMSF in Mexico are higher than in other countries, like the USA. The reason for this difference in fatality rates is currently unknown and could be associated with a genotype of the bacterium, but no comparative molecular typing has been conducted in Mexico to date. The purpose of this study was to analyze 47 RMSF samples with different outcomes from several states in northern Mexico to know the genetic variability of Rickettsia rickettsii, as well as to reconstruct its phylogeny, for which the following intergenic regions were sequenced: RR0155-rpmB, cspA-ksgA, RR1240-tlc5, and Spo0J-abc T1, as well as the following partial genes: ompA, ompB, and gltA. We identified 8 genotypes with different distribution and prevalence among the states analyzed, as well as a different association with case outcome; these genotypes were clustered in 2 clades and 5 lineages were revealed, some of them probably exclusive from Mexico.

The use of readily available laboratory tests for the identification of the emerging yeast Candida auris in Mexico.

Identification of the emerging multidrug-resistant yeast Candida auris is challenging. Here, we describe the role of the Mexico national reference laboratory Instituto de Diagnóstico y Referencia Epidemiológicos Dr. Manuel Martínez Báez (InDRE) and the Mexican national laboratory network in the identification of C. auris. Reference identification of six suspected isolates was done based on phenotypic and molecular laboratory methods, including growth in special media, evaluation of isolate micromorphology, and species-specific PCR and pan-fungal PCR and sequencing. The four C. auris isolates identified were able to grow on modified Sabouraud agar with 10% NaCl incubated at 42 °C. With one exception, isolates of C. auris were spherical to ovoid yeast-like cells and blastoconidia, with no hyphae or pseudohyphae on cornmeal agar. C. auris isolates were resistant to fluconazole. Species-specific and pan-fungal PCR confirmed isolates as C. auris. Sequence analysis revealed the presence of two different C. auris clades in Mexico, clade I (South Asia) and clade IV (South America).

Genetic analysis of the endemic fungal pathogens Coccidioides posadasii and Coccidioides immitis in Mexico.

Coccidioidomycosis (CM) is a mycotic disease that affects mammals, including humans. Official data relative to CM in Mexico has not been collected since 1995, thus its prevalence remains unknown. The objectives of this study were to identify the predominant Coccidioides species in Mexico, infer their current geographical distribution and explore the correlation between species and clinical presentation. We collected 154 strains, which were cultured, inactivated, and processed for DNA extraction. Nine microsatellite loci, the Ag2/PRA gene and Umeyama Region were amplified from each isolate. To infer the current geographical distribution of Coccidioides spp. and to establish a correlation between genotype and clinical presentation, we evaluated genetic population structure under the following grouping criteria: putative origin and clinical presentation records. Microsatellite analysis showed that 82% of the isolates corresponded to C. posadasii and 18% were C. immitis. The species identification results obtained using Umeyama region, Ag2/PRA, and microsatellites of five of the isolates were inconsistent with the data collected for the remaining isolates. C. posadasii strains were found primarily in the northeastern region and C. immitis in the northwestern region. However, there was no relationship between clinical presentation and Coccidioides species. The molecular markers used in this study proved to have a high power of resolution to identify the Coccidioides species recovered in culture. While we found C. posadasii to be the most abundant species in Mexico, more detailed clinical records are needed in order to obtain more accurate information about the infections in specific geographical locations.

[Update on the epidemiology of mycetoma in Mexico. A review of 3933 cases]. / Actualización de la epidemiología del micetoma en México. Revisión de 3,933 casos.

UNLABELLED: Mycetoma is one of the most frequent chronic subcutaneous infections in many tropical and subtropical regions. OBJECTIVE: To update the epidemiological data of mycetoma cases in Mexico. METHOD: A survey in the main mycological diagnosis centers in this country was performed. Each mycologist was requested for number of diagnosed mycetoma cases, age, sex, occupation, geographic origin, type of mycetoma, and etiological agents. RESULTS: Until 2012, we have registered 3,933 cases in the last 54 years. Sex distribution corresponds to 75.6% for men and 24.4% for women. In 75.72% is present in adults between 16-50 years old. The predominant work group of patients is farmers (58.41%) followed by housewives (21.79%). Most of patients come from Jalisco, Morelos, Nuevo Leon, Guerrero, Veracruz and Michoacan states. The most affected body areas are limbs (60.29%) and trunk (19.76%). Actinomycetoma has a frequency of 96.52%, and the commonest etiological agent is Nocardia brasiliensis (65.58%). Eumycetoma (3.48%) is mainly caused by Madurella grisea (28.47%) and M. mycetomatis (26.28%). CONCLUSIONS: Mycetoma is an under-diagnosed pathology representing a health problem in rural regions and must be attended with more interest by the health institutions.

Biochemical identification and molecular characterization (PCR-RFLP) of Nocardia isolates from sputum.

BACKGROUND: Nocardia identification has been based on biochemical and morphological characteristics. However, molecular biology techniques allow a better characterization of species and biotypes that are related to invasive diseases. METHODS: Twelve isolates of Nocardia spp. were obtained from sputum of patients with tuberculosis under retreatment. Identification was done based on morphological characteristics, biochemical tests (casein, tyrosine, xanthine, gelatin, and urea) and molecular biology techniques (PCR-RFLP) using restriction enzymes MspI, HinfI, BsaHI, HaeIII and BstEII. RESULTS: Biochemical tests identified the 12 isolates as Nocardia asteroides. PCR-RFLP technique identified nine isolates to species and biotype level: five as N. asteroides type II, two as N. asteroides type VI, and two as N. asteroides type I. The remaining three isolates were identified as follows: one to species level as N. farcinica and two at genus level as Nocardia sp. CONCLUSIONS: Significant statistical differences between the use of traditional techniques and PCR-RFLP were not found at genus level, but there were important differences at species and biotype level. Biochemical tests identified correctly the actinomycete isolates as belonging to Nocardia genus, but at N. asteroides complex level were not able to discern among their different species. PCR-RFLP is a rapid, non-expensive, and reliable method that allows to discriminate the N. asteroides complex species, identifying biotypes related to invasive disease. Our results suggest that the hospital environment was not a contamination source.

Aspectos micológicos de las micosis pulmonares / Mycotic aspects of fungal diseases located in lung

Las enfermedades por hongos de localización pulmonar no han trascendido completamente en el ámbito médico. Existen a la vez, estrechas semejanzas clínicas, patogénicas e inmunológicas con otras patologías pulmonares, en particular la tuberculosis. De ahí el interés sobre el conocimiento de las micosis pulmonares por hongos patógenos primarios y por hongos oportunistas. Esta división, incluye a la histoplasmosis, coccidioidomicosis, paracoccioidomicosis y blastomicosis como micosis primarias, mientras que la actinomicosis, candidosis sistémica, criptococosis, aspergilosis, nocardiasis y zigomicosis corresponden a las micosis oportunistas. Los aspectos micológicos son fundamentales para el reconocimiento de los elementos parasitarios micósicos y la identificación de los hongos patógenos humanos, lo que garantiza un diagnóstico confiable en estos padecimientos

Microcultivo de dermatofitos en laminillas siliconadas / Silicone coated slide culture method for dermatophytes

Los dermatofitos son muy comunes en la edad pediátrica en una variedad de manifestaciones clínicas denominadas tiñas o empeines. Las especies causantes más frecuentes en México son: Trychophyton rubrum, T. mentagrophytes, T. tonsurans, Microsporum canis y Epidemophyton floccosum. Estos hongos fueron valorados por un método en cultivo líquido con una laminilla siliconada dentro y comparado con la clásica técnica de Ridell. La principal ventaja del método presentado en este trabajo es que el hongo se adhiere a la superficie hidrofóbica de la laminilla con silicona, permitiendo que los microcultivos así obtenidos se manejen con una mayor seguridad. Consideramos que esta técnica sería de gran utilidad en la identificación de hongos de alto riesgo