Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
Más filtros










Tipo de estudio
Intervalo de año de publicación
1.
Food Microbiol ; 85: 103280, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31500706

RESUMEN

Listeria monocytogenes causes severe diseases in humans, including febrile gastroenteritis and systemic infections that has a high mortality despite antibiotic treatment. This pathogen may cause massive outbreaks associated to the consumption of contaminated food products, which highlight its importance in public health. In the last decade, L. monocytogenes has emerged as a foodborne pathogen of major importance in Chile. A previous work showed that in Chile during 2008 and 2009, L. monocytogenes serotypes 1/2a, 1/2b and 4b were the most frequently identified in food and clinical strains. Here we report the molecular characterization of L. monocytogenes strains isolated from 2008 to 2017 in the country. Our results indicate that serotypes 1/2a, 1/2b and 4b continue to be the most commonly found in food products. In addition, we identify persistent and widespread PFGE subtypes. This study reports ten years of epidemiological surveillance ofL. monocytogenes in Chile.


Asunto(s)
Monitoreo Epidemiológico , Microbiología de Alimentos , Enfermedades Transmitidas por los Alimentos/epidemiología , Listeria monocytogenes/genética , Listeriosis/epidemiología , Chile/epidemiología , Recuento de Colonia Microbiana , ADN Bacteriano/genética , Brotes de Enfermedades , Enfermedades Transmitidas por los Alimentos/microbiología , Gastroenteritis/epidemiología , Gastroenteritis/microbiología , Variación Genética , Humanos , Listeria monocytogenes/patogenicidad , Productos de la Carne/microbiología , Epidemiología Molecular , Salud Pública , Serogrupo , Serotipificación , Factores de Virulencia/genética
2.
Artículo en Inglés | MEDLINE | ID: mdl-30627427

RESUMEN

Background: Healthcare-associated infections (HAIs) have a major impact on public health worldwide. Particularly, hospital surfaces contaminated with bacterial pathogens are often the origin of both sporadic cases and outbreaks of HAIs. It has been demonstrated that copper surfaces reduce the microbial burden of high touch surfaces in the hospital environment. Here we report the antimicrobial characterization of a novel composite coating with embedded copper particles, named Copper Armour™. Methods: The Copper Armour™ bactericidal activity was evaluated in in vitro assays against several bacterial pathogens, including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli O157:H7 and Listeria monocytogenes. Additionally, its antimicrobial properties were also evaluated in a pilot study over a nine-week period at an adult intensive care unit. For this, four high touch surfaces, including bed rails, overbed table, bedside table and IV Pole, were coated with Cooper Armour™, and its microbial burden was determined over a nine-week period. Results: Copper Armour™ coated samples showed an in vitro reduction in bacterial burden of > 99.9% compared to control samples. Moreover, pilot study results indicate that Copper Armour™ significantly reduces the level of microbial contamination on high-touch surfaces in the hospital environment, as compared with standard surfaces. Conclusions: Based on its antimicrobial properties, Copper Armour™ is a novel self-sanitizing coating that exhibits bactericidal activity against important human pathogens and significantly reduces the microbial burden of hospital surfaces. This composite could be used as a self-sanitizing coating to complement infection control strategies in healthcare facilities.

3.
Front Microbiol ; 9: 2463, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-30459723

RESUMEN

The coli surface antigen 26 (CS26) of enterotoxigenic Escherichia coli (ETEC) had been described as a putative adhesive pilus based on the partial sequence of the crsH gene, detected in isolates from children with diarrhea in Egypt. However, its production and activity as adherence determinant has not been experimentally addressed. The crsH was identified as a homolog of genes encoding structural subunits of ETEC colonization factors (CFs) CS12, CS18, and CS20. These CFs, along with the recently discovered CS30, belong to the γ2 family of pili assembled by the chaperone-usher pathway (CU pili). Further, the complete CS26 locus, crsHBCDEFG, was described in an O141 ETEC strain (ETEC 100664) obtained from a diarrhea case in The Gambia, during the Global Enterics Multicenter Study. Here, we report that CS26 is a pilus of ∼10 nm in diameter, with the capacity to increase the cell adherence of the non-pathogenic strain E. coli DH10B. As for other related pili, production of CS26 seems to be regulated by phase variation. Deletion of crsHBCDEFG in ETEC 100664 significantly decreased its adherence capacity, which was recovered by in trans complementation. Furthermore, CrsH was cross-recognized by polyclonal antibodies directed against the major structural subunit of CS20, CsnA, as determined by Western blotting and immunogold labeling. ETEC CS26+ strains were found to harbor the heat-labile enterotoxin only, within three different sequence types of phylogroups A and B1, the latter suggesting acquisition through independent events of horizontal transfer. Overall, our results demonstrate that CS26 is an adhesive pilus of human ETEC. In addition, cross-reactivity with anti-CsnA antibodies indicate presence of common epitopes in γ2-CFs.

4.
Microb Pathog ; 123: 259-263, 2018 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-30009972

RESUMEN

Shiga toxin-producing Escherichia coli (STEC) are important foodborne pathogens that can cause severe disease. The ability to adhere to epithelial cells is an important virulence trait and pathogenicity islands (PAIs) play an important role. Recently, researchers identified a member of the Heat-resistant agglutinin family and characterized this antigen named Hemagglutinin from Shiga toxin-producing E. coli (Hes). More importantly, they showed that hes and other genes such as iha, pagC and agn43 were integrated in each of the four modules present in the new PAI named Locus of Adhesion and Autoaggregation (LAA) whose presence is associated with severe disease linked to with LEE-negatives STEC. The distribution of LAA among STEC strains isolates from different origins between 2000 and 2015 from cattle, the farm environment, and food and harboring diverse virulence was investigated. The STEC strains were characterized by PCR to detect three modules of LAA and agn43 (as marker of module IV), and phylogenetic groups were determined. LAA was found in 46% of LEE-negative STEC corresponding to serogroups O91, O174, O113, O171, O178, O130 and others. The presence of this PAI is associated with strains harboring stx2 (56%) and belonging to phylogroup B1 (91%). LAA is a novel pathogenicity island associated with strains isolated from Hemolytic Uremic Syndrome cases. Therefore, the results of this study contribute to a better understanding regarding the pathogenicity of this emergent subset of STEC strains harboring LAA as a predictor of virulence of LEE-negative STEC strains.


Asunto(s)
Proteínas de Escherichia coli/genética , Islas Genómicas/genética , Fosfoproteínas/genética , Serotipificación , Escherichia coli Shiga-Toxigénica/genética , Factores de Virulencia/genética , Adhesinas de Escherichia coli/genética , Animales , Animales Domésticos , Argentina , Proteínas Bacterianas/genética , Bovinos , Análisis por Conglomerados , Escherichia coli/genética , Escherichia coli/patogenicidad , Infecciones por Escherichia coli/veterinaria , Marcadores Genéticos , Genoma Bacteriano , Hemaglutininas , Filogenia , Toxina Shiga I/genética , Toxina Shiga II/genética , Virulencia
5.
Rev. chil. pediatr ; 88(6): 771-775, dic. 2017. tab
Artículo en Español | LILACS-Express | ID: biblio-900050

RESUMEN

Resumen Introducción: El Episodio Hipotonía-Hiporreactividad (EHH) es un efecto adverso tras la vacuna ción, asociado principalmente a vacunas anti-pertussis de células enteras. Se caracteriza por un inicio súbito de flacidez muscular, reducida respuesta a estímulos y palidez cutánea o cianosis. Aunque el EHH es infrecuente, está considerado como un efecto adverso severo. Objetivo: Reportar un caso de EHH posterior a la administración de la vacuna combinada pentavalente con: difteria, tétanos, pertussis celular, hepatitis B y Haemophilus influenzae tipo b (DTwP-HB-Hib), que está incluida en el Programa Nacional de Inmunizaciones (PNI) de Chile, con la finalidad de difundir esta infrecuente complicación de evolución benigna, auto-limitada y de carácter no recurrente. Caso clínico: Lactante de 6 meses de edad, 3 h post-vacunación con la tercera dosis de vacuna DTwP-HB-Hib, presentó compromiso del estado de conciencia interpretado como convulsión atónica y que finalmente se consideró como EHH. El lactante evolucionó favorablemente después de 2 h y fue dado de alta tras 24 h de vigilancia clínica; se cambió el esquema de inmunización del lactante con vacunas anti-per tussis acelulares como medida preventiva. Conclusiones: El desconocimiento sobre el EHH puede desalentar la inmunización infantil. Por lo tanto, es importante que el personal médico informe a los padres de los pacientes sobre este evento benigno, autolimitado y no recurrente. En estos casos, se re comienda continuar con el programa de inmunización del lactante con formulaciones que contengan componentes anti-pertussis acelulares.


Abstract Introduction: Hypotonic-Hyporesponsive Episode (HHE) is an adverse event after vaccination, mainly associated with whole-cell pertussis vaccines. It is characterized by a sudden onset of muscle flaccidity, reduced response to stimuli and pallor or cyanosis. Although the HHE is infrequent, it is considered a severe adverse event. Objective: To report a case of HHE following the administration of the whole-cell pertussis combination vaccine (DTwP-HB-Hib), which is included in National Im munization Program (PNI) of Chile, and to contributing to the knowledge of this adverse event in the country. Case report: A 6-month-old infant, 3 hours post-vaccination with the third dose of DTwP-HB-Hib vaccine, presented a decreased level of consciousness that was interpreted as atonic seizure but finally considered as EHH. The infant progressed favorably after 2 hours of clinical observation and was discharged 24 hours later. Parents were suggested to continue the immunization schedule of the infant with acellular pertussis vaccines as a preventive measure. Conclusions: The lack of knowledge about the EHH may discourage childhood immunization. Therefore, it is important for the medical staff to inform parents of the patients about this benign, self-limited and non-recurrent adverse event. In these cases, it is recommended to continue the immunization schedule of the infant with acellular pertussis vaccines.

6.
Sci Rep ; 7(1): 7011, 2017 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-28765569

RESUMEN

Shiga Toxin-producing Escherichia coli (STEC) are a group of foodborne pathogens associated with diarrhea, dysentery, hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). Shiga toxins are the major virulence factor of these pathogens, however adhesion and colonization to the human intestine is required for STEC pathogenesis. A subset of STEC strains carry the Locus of Enterocyte Effacement (LEE) pathogenicity island (PAI), which encodes genes that mediate the colonization of the human intestine. While LEE-positive STEC strains have traditionally been associated with human disease, the burden of disease caused by STEC strains that lacks LEE (LEE-negative) has increased recently in several countries; however, in the absence of LEE, the molecular pathogenic mechanisms by STEC strains are unknown. Here we report a 86-kb mosaic PAI composed of four modules that encode 80 genes, including novel and known virulence factors associated with adherence and autoaggregation. Therefore, we named this PAI as Locus of Adhesion and Autoaggregation (LAA). Phylogenomic analysis using whole-genome sequences of STEC strains available in the NCBI database indicates that LAA PAI is exclusively present in a subset of emerging LEE-negative STEC strains, including strains isolated from HC and HUS cases. We suggest that the acquisition of this PAI is a recent evolutionary event, which may contribute to the emergence of these STEC.


Asunto(s)
Adhesinas Bacterianas/genética , Infecciones por Escherichia coli/microbiología , Sitios Genéticos , Islas Genómicas , Escherichia coli Shiga-Toxigénica/genética , Factores de Virulencia/genética , Biología Computacional , Genoma Bacteriano , Humanos , Filogenia , Escherichia coli Shiga-Toxigénica/clasificación
7.
Rev Chil Pediatr ; 88(6): 771-775, 2017 Dec.
Artículo en Español | MEDLINE | ID: mdl-29546927

RESUMEN

INTRODUCTION: Hypotonic-Hyporesponsive Episode (HHE) is an adverse event after vaccination, mainly associated with whole-cell pertussis vaccines. It is characterized by a sudden onset of muscle flaccidity, reduced response to stimuli and pallor or cyanosis. Although the HHE is infrequent, it is considered a severe adverse event. OBJECTIVE: To report a case of HHE following the administration of the whole-cell pertussis combination vaccine (DTwP-HB-Hib), which is included in National Im munization Program (PNI) of Chile, and to contributing to the knowledge of this adverse event in the country. CASE REPORT: A 6-month-old infant, 3 hours post-vaccination with the third dose of DTwP-HB-Hib vaccine, presented a decreased level of consciousness that was interpreted as atonic seizure but finally considered as EHH. The infant progressed favorably after 2 hours of clinical observation and was discharged 24 hours later. Parents were suggested to continue the immunization schedule of the infant with acellular pertussis vaccines as a preventive measure. CONCLUSIONS: The lack of knowledge about the EHH may discourage childhood immunization. Therefore, it is important for the medical staff to inform parents of the patients about this benign, self-limited and non-recurrent adverse event. In these cases, it is recommended to continue the immunization schedule of the infant with acellular pertussis vaccines.


Asunto(s)
Trastornos de la Conciencia/etiología , Vacuna contra Difteria, Tétanos y Tos Ferina/efectos adversos , Vacunas contra Haemophilus/efectos adversos , Vacunas contra Hepatitis B/efectos adversos , Hipotonía Muscular/etiología , Palidez/etiología , Humanos , Lactante , Masculino
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA