Streptococcus agalactiae virulence factors isolated from bovine mastitis and antibiotic treatment response.

AIMS: This study aims to characterize the virulence factors of Streptococcus agalactiae strains isolated from bovine mastitis and their potential association with the antibiotic treatment response. METHODS AND RESULTS: Four different profiles were identified among the 181 S. agalactiae strains using polymerase chain reaction, of which hyl B and cylE were found in 100% of the isolated strains, followed by cfb (99.5%), scpB (40.3%), and lmb (15.5%). The cell invasion assay showed that lmb-positive strains exhibited higher invasion ability than lmb-negative. There was a significant association (P = 0.018) between lmb gene and cows that required more than one treatment cycle. CONCLUSIONS: These results showed that intramammary infections caused by lmb-carrier S. agalactiae strains did not adequately respond to the antibiotics administered, likely because of the presence of this virulence factor, which potentially favours the cell invasion capacity of these strains.

Evaluation of three Staphylococcus aureus proteins involved in the adhesion process as antigens for the detection of bovine intramammary infections.

Introduction. Fast and accurate diagnosis is one of the key strategies in the successful control of intramammary infections caused by Staphylococcus aureus. Immunoassays are one of the diagnostic tools that have been proposed for the detection of S. aureus infection because they offer an advantage in terms of cost and are fast and easy to use compared to other diagnostic tests.Gap statement. The main challenge of the immunoassays is to identify antigens or serological markers that allow accurate discrimination between infected and uninfected cows with S. aureus, since this bacterium can naturally colonize different areas of the animal body.Aim. To evaluate three S. aureus proteins (IsdA, ClfA, SdrD) involved in the adhesion process as antigens to detect indicator antibodies of bovine intramammary infections.Methodology. Ninety-six cows in lactation and not vaccinated against S. aureus were included. Forty-eight of these cows were infected with S. aureus, while the rest (n=48 cows) were uninfected. Blood and milk samples were collected from each animal to recover serum and whey. IgG titres against the three proteins individually and combined (Mix) were measured in each sample using an enzyme-linked immunosorbent assay (ELISA) test.Results. Significant differences in the IgG response against the proteins evaluated were observed, highlighting the antigenic potential of IsdA and demonstrating that some antigens can detect specific antibodies of infection better than others. According to receiver operating characteristic (ROC) curve analysis, the combined proteins showed the most remarkable capacity (sensitivity of 79 % and specificity of 77 %) to differentiate between infected and uninfected cows when blood samples were used. In addition, the combined proteins also showed the highest specificity (94 %) when using milk samples.Conclusion. Our findings provide information on the usefulness of three adhesion-associated S. aureus proteins in detecting serological markers of intramammary infections in bovines.

Urban versus Rural Prevalence of Intestinal Parasites Using Multi-Parallel qPCR in Colombia.

Stool samples from 122 children living in an urban slum (n = 72) and rural (n = 50) areas were analyzed using multi-parallel real-time quantitative PCR to determine intestinal prevalence parasites from two communities in Colombia. Findings indicated a prevalence of 86.1% Blastocystis spp., 62.5% Giardia intestinalis, 19.4% Cryptosporidium spp., 19.4% Ascaris lumbricoides, and 5.6% Trichuris trichiura in an urban slum; and 76% Blastocystis spp., 68% G. intestinalis, 20% Entamoeba histolytica, 50% A. lumbricoides, 46% T. trichiura, and 2% Strongyloides stercoralis in rural areas. Polyparasitism was higher in rural (58%) than urban (25%) areas (P = 0.001). Trichuris trichiura burden was higher in the rural area (P = 0.002). Over 40% of helminthic infections in rural areas had a heavy parasite burden by WHO classification. Over half of urban and rural children were infected with G. intestinalis and Blastocystis spp. Our data provide accurate epidemiologic surveillance for public health interventions.

Phenotypic Characterization and Whole Genome Analysis of a Strong Biofilm-Forming Staphylococcus aureus Strain Associated With Subclinical Bovine Mastitis in Colombia.

Staphylococcus aureus represent a serious threat to public health due to food safety, antibiotic resistance, and the potential zoonotic transmission of strains between dairy cattle and humans. Biofilm formation by S. aureus results in chronicity of the infections which confers protection against the immune response and antibiotics. Likewise, biofilm allows the exchange of mobile genetic material among different strains through microbial interactions inside the matrix. In Colombia, where S. aureus continues to be one of the main pathogens isolated from bovine intramammary infections and where milking by hand is highly frequent, there are knowledge gaps on the zoonotic potential of the strains. Therefore, the aim of this work was to characterize genotypically and phenotypically the S. aureus Sa1FB strain with strong biofilm production and to perform genomic and phenotypic comparisons with other relevant S. aureus strains (native and references strains). These results show a highly productive strain of biofilm and a low ability of cell invasion compared to the other two native strains. In addition, high genomic similarity between S. aureus Sa1FB and the reference strains was observed, despite of the differences reported at the clinical level. However, Sa1FB exhibited special features in terms of mobile genetic elements, highlighting its ability to accept foreign genetic material. Indeed, this could increase mutation, pathogenesis, and adaptability to new hosts, representing a risk for people in contact with the milk obtained from animals infected with these strains. These results present the relevance of surveillance for early detection of emergent clones with zoonotic potential, which reduces the risk of occupational exposure and their spread in the community.

Metagenomic characterization of bacterial biofilm in four food processing plants in Colombia.

Bacteria inside biofilms are more persistent and resistant to stress conditions found in the production environment of food processing plants, thus representing a constant risk for product safety and quality. Therefore, the aim of this study was to characterize, using 16S rRNA sequencing, the bacterial communities from biofilms found in four food processing plants (P1, P2, P3, and P4). In total, 50 samples from these four processing plants were taken after cleaning and disinfection processes. Four phyla: Proteobacteria, Firmicutes, Actinobacteria, and Bacteroides represented over 94% of the operational taxonomic units found across these four plants. A total of 102 families and 189 genera were identified. Two genera, Pseudomonas spp. and Acinetobacter spp., were the most frequently found (93.47%) across the four plants. In P1, Pseudomonas spp. and Lactobacillus spp. were the dominant genera, whereas Lactobacillus spp. and Streptococcus spp. were identified in P2. On the other hand, biofilms found in P3 and P4 mainly consisted of Pseudomonas spp. and Acinetobacter spp. Our results indicate that different bacterial genera of interest to the food industry due to their ability to form biofilm and affect food quality can coexist inside biofilms, and as such, persist in production environments, representing a constant risk for manufactured foods. In addition, the core microbiota identified across processing plants evaluated was probably influenced by type of food produced and cleaning and disinfection processes performed in each one of these.

Aspectos principales del espacio urbano y la seguridad ciudadana desde la perspectiva de Bogotá / Major aspects of urban space and citizen security and safety seen from a Bogota perspective / Aspectos principais do espaço urbano e da segurança do cidadão desde a perspectiva de Bogotá

Se conceptualizan algunos rasgos principales del espacio urbano, a partir de una revisión teórica para explicar la relación con el discurso de la seguridad ciudadana, teniendo como referencia metodológica el análisis crítico del discurso (ACD) y con el objetivo de ser un aporte para futuras investigaciones en esta línea. Las problemáticas de las grandes ciudades, como la segregación, la fragmentación y la densidad poblacional, se concretan por medio del mapeo de Bogotá (2011-2013) y en el marco del Plan Integral de Convivencia y Seguridad Ciudadana (PICSC, 2013-2023). El trabajo concluye que es necesario analizar el significado del espacio físico de la ciudad frente a la seguridad ciudadana, y formular políticas públicas a partir de esta comprensión, para fortalecer la interacción social, así como para recuperar el espacio urbano en toda su dimensión política.

Some of the main features of urban space are conceptualized here from a theoretical outlook in order to explain their relationship with the citizen security and safety, with the "ACD", the critical discourse analysis as a methodological reference and the objective of providing a contribution for future research in this line. The problems faced in big cities such as segregation, fragmentation and population density are specified by means of a chart of Bogota (2011-2013) and within the framework of the Integral Coexistence and Citizen Security Plan (ICCSP, 2013-2023). In this work it is concluded that there is a need not only to analyze the meaning of physical space in the city vis-à vis public safety and security, but also to formulate public policies from this insight in order to strengthen social interaction and recover urban space in its whole political dimension.

Algumas características principais do espaço urbano são conceptualizadas, a partir de uma revisão teórica para explicar a relação com o discurso da segurança do cidadão, tendo como referência metodológica a análise crítica do discurso (ACD) e com o objetivo de ser uma contribuição para as investigações futuras nesta linha. As problemáticas das cidades grandes, como a segregação, a fragmentação e a densidade da população, concretam-se a través do mapeamento de Bogotá (2011-2013) e no marco do Plano Integral de Convivência e da Segurança do Cidadão (PICSC, 2013-2023). O trabalho conclui que é necessário analisar o significado do espaço físico da cidade perante a segurança do cidadão, e formular políticas públicas a partir desta compreensão, para fortalecer a interação social, assim como para recuperar o espaço urbano em toda sua dimensão política.

[Concordance between thick blood smear, immunochromatography and polymerase chain reaction for malaria diagnosis]. / Concordancia entre gota gruesa, inmunocromatografía y reacción en cadena de la polimerasa para el diagnóstico de malaria.

INTRODUCTION: The rapid and effective diagnosis of malaria is the determining condition for an appropriate treatment and control of the disease. OBJECTIVE: The sensitivity, specificity and the positive and negative predictive values were evaluated in cases of suspected malaria in Colombia in a comparison of a rapid diagnostic test. the PCR test and the thick blood smear-the traditional gold standard. MATERIALS AND METHODS: A group of 100 patients with symptoms compatible with malaria, were included in the study. They were selected from the following Colombian regions: Urabá, Córdoba, lower Cauca, and relatively fewer from other malaria endemic areas of Colombia including the provinces of Valle, Chocó in the central west of Colombia and Vichada to the east. To each patient the following three tests were performed: the rapid OptiMAL test, the PCR identification and the thick blood smear. The PCR amplified specific DNA sequences with primers designed to identify the genus Plasmodium, and the two species present in Colombia, P. falciparum and P. vivax. RESULTS: The sensitivity of the rapid test versus the thick smear, for the diagnosis of both species of Plasmodium was 93.9% (95% CI: 87-100%) and the specificity was 94.3% (95% CI:.253 85-100%). The PCR compared with the thick smear showed a sensitivity of 100% (95% CI: 99-100%) and a specificity of 97.1% (95% CI: 90-100%). CONCLUSIONS: The sensitivity and specificity of the three tests did not present statistically significant differences. However, the thick blood smear was recommended as the standard test, mainly due to its low cost.

Concordancia entre gota gruesa, inmunocromatografía y reacción en cadena de la polimerasa para el diagnóstico de malaria / Concordance between thick blood smear, immunochromatography and polymerase chain reaction for malaria diagnosis

Introducción. El diagnóstico oportuno y efectivo de la malaria son condiciones determinantes para hacer un tratamiento adecuado de la enfermedad y uncontrol de la misma. Objetivo. Se evaluó la concordancia de la sensibilidad, especificad, valor predictivo positivo y negativo de una prueba rápida y de la reacción en cadena de la polimerasa (PCR), con la prueba estándar, la gota gruesa, para el diagnóstico de la malaria. Materiales y métodos. Se analizó una población de 100 pacientes con signos y síntomas compatibles con malaria, procedentes de las zonas de Urabá, Córdoba, Bajo Cauca, y de otras regiones de Colombia como el Valle, Chocó y Vichada, todas áreas endémicas de alaria. A cada paciente se le practicó una gota gruesa, la prueba rápida OptiMAL® y la amplificación a través de una PCR de secuencias de ADN especificas para género Plasmodium, P. falciparum y P. vivax. Resultados. La sensibilidad de la prueba rápida frente a la gota gruesa, para el diagnóstico de ambas especies de Plasmodium fue de 93,85por ciento (IC 95 por ciento: 87,23- 100) y la especificidad de 94,29 por ciento (IC 95 por ciento:85,17-100). La PCR comparada con la gota gruesa mostró una sensibilidad de 100 por ciento (IC 95por ciento: 99,23-100) y una especificidad de 97,14 por ciento(IC 95 por ciento: 90,19-100). Conclusiones. Estos hallazgos muestran que la sensibilidad y especificidad de la prueba rápida y la PCR para el diagnóstico de la malaria son comparables con el examen al microscopio de la gota gruesa recomendada por su eficacia y bajo costo.