Nocardia brasiliensis is the main agent of actinomycetoma in Mexico, but little is known about its virulence and molecular pathogenic pathways. These facultative intracellular bacteria are able to survive and divide within the host phagocytic cells, in part by neutralizing the reactive oxygen intermediates. Superoxide dismutase (SOD) participates in the intracellular survival of several bacterial species and, in particular, constitutes one of Nocardia asteroides virulence factors. To clarify SOD participation in the N. brasiliensis early infective process, we report its isolation and the consequent comparison of its transcript level. A 630 bp polymerase chain reaction fragment that included most of the coding sequence of N. brasiliensis sodA was cloned. A competitive assay was developed, allowing comparison of bacterial sod expression in exponential culture and 1 h after infecting peritoneal macrophages from BALB/c mice. At that time, there were viable bacteria in the macrophages. The intracellular bacteria presented a clear decrease in their sod transcript amount, although their 16S rRNA (used as an internal control) and hsp levels were maintained or slightly increased, respectively. These results indicate that sodA transcription is not maintained within the SOS bacterial response induced by phagosomal conditions. Further kinetics will be necessary to precisely define sod transcriptional regulation during N. brasiliensis intra-macrophage growth.

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Introduction: Insulin resistance (IR) is a major risk factor for developing diabetes mellitus type 2 and cardiovascular diseases. In pediatrics, morbidity and mortality associated with these diseases highlights the diagnostic importance of IR for primary care.Objective: To determine Homeostatic Model Assessment Insulin Resistance (HOMA-IR) values and their correlation with BMI-for-age percentile in children and adolescents of the Soconusco region of Chiapas, Mexico.Materials and methods: Cross-sectional study. Overweight and obesity prevalence was determined based on the Body Mass Index (BMI) percentile of 112 children (5-19 years old). Glucose and fasting insulin values were quantified and used for estimation of HOMA-IR.Results: The combined prevalence of obesity and overweight was 66%, with insulin (p=0.010) and HOMA-IR (p=0.015) values higher than those of the normal weight group. The HOMA-IR values correlated positively with age (r=0.636), weight (r=0.569), height (r=0.578) and BMI percentile (r=0.198).Conclusions: In the study population, HOMA-IR has a moderately significant correlation with an increase in BMI percentile.

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