Elva Bazán-Mora

Dynamics of dermatophytosis frequency in Mexico: an analysis of 2084 cases.

We analysed 15,101 biological samples from patients presenting with superficial mycoses who attended outpatient services over a 10-year period. Scale samples were processed for direct microscopic examination with 15% KOH and cultured on Sabouraud glucose agar plus chloramphenicol and cycloheximide. Laboratory examination confirmed 4,709 cases of superficial mycosis (31.18%), of which 2,084 (44.26%) were dermatophytoses. The species most frequently encountered was Trichophyton rubrum (71.2%), followed by T. tonsurans (6.9%), T. mentagrophytes (5.5%), Microsporum canis (4.5%) and Epidermophyton floccosum (1.3%). The most frequent clinical form of dermatophytosis was tinea unguium (59.9%), followed by tinea pedis (24.5%). We demonstrate that the number of cases of T. rubrum is increasing in Mexico.

Frecuencia de micosis en pacientes inmunosuprimidos de un hospital regional de la Ciudad de México

Objective. To isolate and identify the fungi in specimens collected from immunocompromised patients seen in Mexico City hospital, and to assess their association with mycosis. Material and Methods. A total of 268 specimens from 108 patients were processed for mycological study, including direct examination, smears, cultures, and microcultures in specific media, in addition to biochemical tests. Most of the patients had been diagnosed with pulmonary tuberculosis and Acquired Immunodeficiency Syndrome (AIDS). Results. One hundred and eighty-three yeasts and 66 mycelial fungi were isolated. Forty-five mycoses were diagnosed; the most frequent mycosis was pulmonary candidosis (32 cases). Candida albicans and C parapsilosis were the predominant species associated with mycotic infection. Five Cryptococcus neoformans var. neoformans, one C albidus, three Histoplasma capsulatum and one Geotrichum candidum isolats were associated with mycosis. Conclusions. Of the studied patients, 41.6% showed a mycotic infection, principally associated with AIDS and pulmonary tuberculosis. The English version of this paper is available at: http:// www.insp.mx/salud/index.html

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.

Cellulose-Silica Nanocomposites of High Reinforcing Content with Fungi Decay Resistance by One-Pot Synthesis

Hybrid bionanocomposites based on cellulose matrix, with silica nanoparticles as reinforcers, were prepared by one-pot synthesis of cellulose surface modified by solvent exchange method to keep the biopolymer net void for hosting inorganic nanoparticles. Neither expensive inorganic-particle precursors nor crosslinker agents or catalysts were used for effective dispersion of reinforcer concentration up to 50 wt %. Scanning electron microscopy of the nanocomposites shows homogeneous dispersion of reinforcers in the surface modified cellulose matrix. The FTIR spectra demonstrated the cellulose features even at 50 weight percent content of silica nanoparticles. Such a high content of silica provides high thermal stability to composites, as seen by TGA-DSC. The fungi decay resistance to Trametes versicolor was measured by standard test showing good resistance even with no addition of antifungal agents. This one-pot synthesis of biobased hybrid materials represents an excellent way for industrial production of high performance materials, with a high content of inorganic nanoparticles, for a wide variety of applications.