Virulence genes, antimicrobial resistance profile, phylotyping and pathotyping of diarrheagenic Escherichia coli isolated from children in Southwest Mexico.

Diarrheagenic E. coli (DEC) strains are one of the most important etiology factors causing diarrhea in children worldwide, especially in developing countries. DEC strains have characteristic virulence factors; however, other supplemental virulence genes (SVG) may contribute to the development of diarrhea in children. Therefore, this study aimed to determine the prevalence of DEC in children with diarrhea in southwestern Mexico and to associate childhood symptoms, SVG, and pathotypes with diarrhea-causing DEC strains. DEC strains were isolated from 230 children with diarrhea aged 0-60 months from the state of Oaxaca, southwestern Mexico; clinical data were collected, and PCR was used to identify SVG and pathotypes. Antibiotic resistance profiling was performed on DEC strains. 63% of samples were DEC positive, single or combined infections (two (21%) or three strains (1.3%)) of aEPEC (51%), EAEC (10.2%), tEPEC (5.4%), DAEC (4.8%), ETEC (4.1%), EIEC (1.4%), or EHEC (0.7%) were found. Children aged ≤ 12 and 49-60 months and symptoms (e.g., fever and blood) were associated with DEC strains. SVG related to colonization (nleB-EHEC), cytotoxicity (sat-DAEC and espC-tEPEC), and proteolysis (pic-aEPEC) were associated with DECs strains. E. coli phylogroup A was the most frequent, and some pathotypes (aEPEC-A, DAEC-B), and SVG (espC-B2, and sat-D) were associated with the phylogroups. Over 79% of the DEC strains were resistant to antibiotics, and 40% were MDR and XDR, respectively. In conclusion aEPEC was the most prevalent pathotype in children with diarrhea in this region. SVG related to colonization, cytotoxicity, and proteolysis were associated with diarrhea-producing DEC strains, which may play an essential role in the development of diarrhea in children in southwestern Mexico.

Reducción del tiempo de cicatrización por medio de laser de helio-neón. Modelo experimental en conejos / Reduction in wound healing by treatening wounds by helius-neon laser. An experimental model in rabbits

El objetivo del trabajo fue determinar las condiciones óptimas para una aceleración de la cicatrización en piel de conejos mediante el tratamiento de la herida con laser de helio-neón HeNe (632.8 nm). Para este fin se usaron dos grupos de 5 conejos cada uno, en uno se aplicó el tratamiento con laser y el otro sirvió de control. A los animales se les realizó un resección de piel de 2 x 5 cm. El grupo experimental se irradió con laser helio-neón con una potencia de 0.1 mW a una distancia aproximada de 3 cm, con un barrido en toda la herida, por un lapso de 5 min/día. Se tomó biopsia después de las 24 horas al primer conejo, posteriormente, cada 24 horas se tomó un conejo distinto y se realizó el análisis histológico. En el grupo experimental se observó un aumento en la actividad de los procesos de reparación, en comparación con el grupo control, como fue la proliferación de fibroblastos y el incremento en la fibras de colágena que sellaron la herida a partir del cuarto día. En las condiciones antes mencionadas se redujo el tiempo de cicatrización, por lo menos en un 40 por ciento comparado con el grupo control