Genetic Analysis Method for Staphylococcus chromogenes Associated with Goat Mastitis.

Mastitis in goats is mainly caused by coagulase-negative Staphylococcus (CNS). The identification methods for this group are based on evaluating the expression of phenotypic characteristics such as the ability to metabolize various substrates; however, this is disadvantageous as these methods are dependent on gene expression. In recent years, genotyping methods such as the Multiple Locus Variable-Number Tandem Repeat Analysis (MLVA) and gene identification have been useful for epidemiological study of several bacterial species. To develop a genotyping method, the genome sequence of Staphylococcus chromogenes MU970 was analysed. The analysis showed nine virulence genes described in Staphylococcus aureus. The MLVA was developed using four loci identified in the genome of S. chromogenes MU970. This genotyping method was examined in 23 strains of CNS isolated from goat mastitis. The rate of discrimination for MLVA was 0.8893, and the highest rates of discrimination per the index of Simpson and Hunter-Gaston were 0.926 and 0.968 for the locus 346_06, respectively. The virulence genes were present in all strains of S. chromogenes but not in other CNS. The genotyping method presented in this paper is a viable and easy method for typifying CNS isolates from mastitis cases in different regions and is an ideal mean of tracking this disease.

Characterization of Salmonella spp. and E. coli Strains Isolated from Wild Carnivores in Janos Biosphere Reserve, Mexico.

Enterobacteriaceae are considered one the most important zoonotic pathogens. In this study, we analyzed the characteristics of E. coli and Salmonella spp. strains present in carnivores from Janos Biosphere Reserve, Mexico. These microorganisms had been isolated from a wide range of domestic and free-range animals, including wild carnivores. Fifty-five individuals were sampled, and the presence of Salmonella and E. coli was determined by bacteriological standard methods. Strains isolated were characterized by molecular methods and in vitro infection assays. Eight different species of carnivores were captured, including coyotes (Canis latrans), gray fox (Urocyon cinereoargenteus), desert foxes (Vulpes macrotis), striped skunks (Mephitis mephitis), hooded skunks (Mephitis macroura), lynxes (Lynx rufus), raccoons (Procyon lotor), and badgers (Taxidea taxus). Salmonella spp. and E. coli were isolated from four species of carnivores. Five Salmonella spp. strains were isolated, and their molecular characterization revealed in three of them the presence of fimbrial and virulence genes associated with cell invasion. In vitro evaluation of these strains showed their capability to invade human Hep2 cells. Sixty-one E. coli strains were isolated; different serotypes and phylogroups were observed from these strains. Additionally, the presence of virulence genes showed differently.

Cytolethal Distending Toxin From Campylobacter jejuni Requires the Cytoskeleton for Toxic Activity.

BACKGROUND: Campylobacter jejuni is one of the major causes of infectious diarrhea worldwide. The distending cytolethal toxin (CDT) of Campylobacter spp. interferes with normal cell cycle progression. This toxic effect is considered a result of DNase activity that produces chromosomal DNA damage. To perform this event, the toxin must be endocytosed and translocated to the nucleus. OBJECTIVES: The aim of this study was to evaluate the role of the cytoskeleton in the translocation of CDT to the nucleus. METHODS: Campylobacter jejuni ATCC 33291 and seven isolates donated from Instituto de Biotecnologia were used in this study. The presence of CDT genes in C. jejuni strains was determined by PCR. To evaluate the effect of CDT, HeLa cells were treated with bacterial lysate, and the damage and morphological changes were analyzed by microscopy, immunofluorescence staining, and flow cytometry. To evaluate the role of the cytoskeleton, HeLa cells were treated with either latrunculin A or by nocodazole and analyzed by microscopy, flow cytometry, and immunoquantification (ELISA). RESULTS: The results obtained showed that the eight strains of C. jejuni, including the reference strain, had the ability to produce the toxin. Usage of latrunculin A and nocodazole, two cytoskeletal inhibitors, blocked the toxic effect in cells treated with the toxin. This phenomenon was evident in flow cytometry analysis and immunoquantification of Cdc2-phosphorylated. CONCLUSIONS: This work showed that the cytotoxic activity of the C. jejuni CDT is dependent on its endocytosis. The alteration in the microtubules and actin filaments caused a blockage transit of the toxin, preventing it from reaching the nucleus of the cell, as well as preventing DNA fragmentation and alteration of the cell cycle. The CDT toxin appears to be an important element for the pathogenesis of campylobacteriosis, since all clinical isolates showed the presence of cdtA, cdtB and cdtC genes.

Nivel de riesgo e incidencia de caries en niños atendidos en clínica estomatológica de pregrado / Risk level and caries incidence in children attended at a predoctoral stomatology clinic

Antecedentes: La caries tiene etiología multifactorial, se presenta por desbalance entre factores patológicos y protectores, es un problema de salud pública que en México afecta a 95% de los niños. Objetivo: Determinar la prevalencia de caries, establecer el nivel de riesgo y evaluar su relación con la incidencia de caries a los tres y seis meses. Material y métodos: Estudio observacional, descriptivo y longitudinal en clínica estomatológica de una universidad ubicada al sur de la Ciudad de México. Previo consentimiento informado, se realizó revisión bucal por dos cirujanos dentistas calibrados para el diagnóstico de caries/ICDAS (kappa 95.37%), llevada a cabo en sillón dental con luz artificial bajo principios para el control de infecciones. Se estableció nivel de riesgo mediante el Sistema Internacional para la Gestión de Caries/ICCMS empleando como indicadores: consumo de alimentos cariogénicos (Lipari/Andrade), pH (tiras Hidryon), prueba de saliva estimulada, experiencia de caries (CPOD/ceod), higiene bucal (O'Leary) y cultivo de Streptococcus mutans. Se realizó análisis estadístico para determinar medidas de tendencia central, dispersión y asociación entre variables mediante exacta de Fisher, STATA.SE/10. Resultados: La población en estudio fue de 42 niños con rango de edad de tres a 15 años, mediana de 7.04 (RIC = 5-9). La prevalencia de caries fue 95.23%, con estadios severos en 83.3%, el nivel de riesgo fue alto en 73.7% y se asoció con severidad de caries (p = 0.000), consumo de carbohidratos (p = 0.000), experiencia de caries (ceod) (p = 0.000) y S. mutans (p = 0.000). La incidencia de caries a los tres meses fue de 71.0% y a los seis meses de 11.1%. Conclusiones: La prevalencia de caries fue alta (95.23%) así como el riesgo de caries (73.7%), con elevada incidencia a tres meses (71%), aun cuando los pacientes estaban en tratamiento odontológico. La atención restaurativa prevalece a pesar de hacer diagnóstico de lesiones reversibles y determinación del nivel de riesgo (AU)

Background: Caries has multifactorial etiology, presented by the imbalance between pathological/protective factors, is a public health problem, affecting 95% of children in México. Objective: To determine the prevalence of caries, to establish the level of risk and to evaluate its relation with incidence of caries at three and six months. Material and methods: Observational, descriptive and longitudinal study in the stomatologic clinic of the UAM-Xochimilco. Before informed consent, oral revision was performed by two dental surgeons calibrated for the diagnosis of caries/ICDAS (kappa 95.37%), carried out in dental chair with artificial light under principles for the control of infections. Risk level was established through the International System for Caries Management/ICCMS; using as indicators: consumption of cariogenic foods (Lipari/Andrade), pH (Hidryon strips), stimulated saliva test, caries experience (CPOD/ceod), oral hygiene (O'Leary) and culture of Streptococcus mutans. Statistical analysis was performed to determine measures of central tendency, dispersion and association between variables with Fisher's exact, STATA.SE/10. Results: The study population consisted of 42 children with ages ranging from 3 to 15 years, median of 7.04 (Q1 = 5-Q3 = 9). The prevalence of caries was 95.23%, with severe stages in 83.3%, the risk level was high in 73.7% and was associated with caries severity (p = 0.000), carbohydrate consumption (p = 0.000), caries experience (ceod) (p = 0.000) and S. mutans (p = 0.000). The incidence of caries at three months was 71.0% and at six months 11.1%. Conclusions: The prevalence of caries was high (95.23%), as well as the risk for caries (73.7%), and high incidence at three months (71%), despite the fact that the patients were in dental treatment. Restorative care prevails despite the diagnosis of reversible lesions and determination of the level of risk (AU)