Comparative proteomic analysis of the hemolymph and salivary glands of Rhodnius prolixus and R. colombiensis reveals candidates associated with differential lytic activity against Trypanosoma cruzi Dm28c and T. cruzi Y.

BACKGROUND: Immune response of triatomines plays an important role in the success or failure of transmission of T. cruzi. Studies on parasite-vector interaction have shown the presence of trypanolytic factors and have been observed to be differentially expressed among triatomines, which affects the transmission of some T. cruzi strains or DTUs (Discrete Typing Units). METHODOLOGY/PRINCIPAL FINDINGS: Trypanolytic factors were detected in the hemolymph and saliva of R. prolixus against epimastigotes and trypomastigotes of the Y strain (T. cruzi II). To identify the components of the immune response that could be involved in this lytic activity, a comparative proteomic analysis was carried out, detecting 120 proteins in the hemolymph of R. prolixus and 107 in R. colombiensis. In salivary glands, 1103 proteins were detected in R. prolixus and 853 in R. colombiensis. A higher relative abundance of lysozyme, prolixin, nitrophorins, and serpin as immune response proteins was detected in the hemolymph of R. prolixus. Among the R. prolixus salivary proteins, a higher relative abundance of nitrophorins, lipocalins, and triabins was detected. The higher relative abundance of these immune factors in R. prolixus supports their participation in the lytic activity on Y strain (T. cruzi II), but not on Dm28c (T. cruzi I), which is resistant to lysis by hemolymph and salivary proteins of R. prolixus due to mechanisms of evading oxidative stress caused by immune factors. CONCLUSIONS/SIGNIFICANCE: The lysis resistance observed in the Dm28c strain would be occurring at the DTU I level. T. cruzi I is the DTU with the greatest geographic distribution, from the south of the United States to central Chile and Argentina, a distribution that could be related to resistance to oxidative stress from vectors. Likewise, we can say that lysis against strain Y could occur at the level of DTU II and could be a determinant of the vector inability of these species to transmit T. cruzi II. Future proteomic and transcriptomic studies on vectors and the interactions of the intestinal microbiota with parasites will help to confirm the determinants of successful or failed vector transmission of T. cruzi DTUs in different parts of the Western Hemisphere.

Clinical and epidemiological features of tuberculosis isolated from critically ill patients / Tuberculosis en la unidad de cuidados intensivos: características clínicas y epidemiológicas

Human tuberculosis is still a major world health concern. In Uruguay, contrary to the world trend, an increase in cases has been observed since 2006. Although the incidence of MDR-resistant strains is low and no cases of XDR-TB were registered, an increase in the number of patients with severe tuberculosis requiring critical care admission was observed. As a first aim, we performed the analysis of the genetic structure of strains isolated from patients with severe tuberculosis admitted to an intensive care unit. We compared these results with those corresponding to the general population observing a statistically significant increase in the Haarlem genotypes among ICU patients (53.3% vs 34.7%; p;<;0.05). In addition, we investigated the association of clinical outcomes with the genotype observing a major incidence of hepatic dysfunctions among patients infected with the Haarlem strain (p;<;0.05). The cohort presented is one of the largest studied series of critically ill patients with tuberculosis.

La tuberculosis (TB) aún representa un problema mayor de salud pública. En Uruguay, contrariamente a la tendencia mundial, se ha observado un incremento en el número de casos desde 2006. Aunque la incidencia de casos de multidrogorresistencia (MDR) es baja y no se han reportados casos de resistencia a fármacos de primera y segunda línea de tratamiento (XDR), se ha observado un incremento en el número de casos con TB grave, que requieren internación en unidad de terapia intensiva (CTI). Como primer objetivo del presente trabajo, se analizó la estructura genética de cepas de Mycobacterium tuberculosis aisladas de pacientes internados en CTI. Comparamos estos resultados con los obtenidos con cepas circulantes en la comunidad. Observamos un incremento estadísticamente significativo del genotipo Haarlem en los pacientes internados en CTI (53,3 vs. 34,7%; p;<;0,05). Además, investigamos la asociación del desenlace clínico con el genotipo, y encontramos una mayor incidencia de disfunción hepática en los pacientes infectados con la cepa Haarlem (p;<;0,05). La cohorte presentada en este trabajo corresponde a una de las series con mayor número de pacientes con tuberculosis que requirieron internación en CTI.