ABSTRACT
Clostridium perfringens es un bacilo grampositivo anaerobio con capacidad de formar esporas. Es uno de los patógenos bacterianos con mayor distribución en el medio ambiente, ya que puede ser aislado de muestras de suelo y de agua y además forma parte de la microbiota intestinal de animales y humanos. Sin embargo, en ciertas ocasiones puede actuar como patógeno oportunista y causar enfermedades como la gangrena gaseosa, la enterotoxemia del ovino y del caprino y la disentería del cordero, entre otras. En humanos, está asociado a enfermedades como la intoxicación por alimentos, la enterocolitis necrotizante en niños y la enteritis necrótica o pigbel de las tribus de Papúa-Nueva Guinea. El renovado interés que existe actualmente en el estudio de C. perfringens como patógeno veterinario y humano, junto con el avance de la biología molecular, han hecho posible que la ciencia tenga hoy un conocimiento más profundo sobre la biología y la patogenia de esta bacteria. En esta revisión bibliográfica se discuten y actualizan los principales aspectos de la patogenia intestinal de C. perfringens teniendo en cuenta las toxinas con mayor importancia médica descritas hasta el presente.
Clostridium perfringens is an anaerobic gram-positive spore-forming bacillus. It is one of the pathogens with larger distribution in the environment; it can be isolated from soil and water samples, which also belongs to the intestinal flora of animals and humans. However, on some occasions it can act as an opportunistic pathogen, causing diseases such as gas gangrene, enterotoxemia in sheep and goats and lamb dysentery, among others. In human beings, it is associated to diseases such as food poisoning, necrotic enterocolitis of the infant and necrotic enteritis or pigbel in Papua-New Guinea tribes. The renewed interest existing nowadays in the study of C. perfringens as a veterinarian and human pathogen, together with the advance of molecular biology, had enabled science to have deeper knowledge of the biology and pathology of these bacteria. In this review, we discuss and update the principal aspects of C. perfringens intestinal pathology, in terms of the toxins with major medical relevance at present.
Subject(s)
Animals , Humans , Bacterial Toxins , Clostridium perfringens/metabolism , Animal Diseases/microbiology , Bacterial Toxins/adverse effects , Bacterial Toxins/classification , Bacterial Toxins/pharmacology , Bacterial Toxins/toxicity , Clostridium Infections/microbiology , Clostridium Infections/veterinary , Clostridium perfringens/pathogenicity , Environmental Microbiology , Enteritis/microbiology , Enteritis/veterinary , Enterotoxins/physiology , Food Microbiology , Intestines/microbiologyABSTRACT
V. cholerae non-O1 non-O139 serogroups isolated from clinical and environmental sources in Córdoba, Argentina, were analyzed for the presence and expression of virulence genes. Most of the strains studied contained the genes toxR and hlyA, but lacked ctxA, zot, ace, tcpA and stn. The culture supernatants were tested for hemolytic and cytotoxic activity. The enterotoxic potential of the strains was studied in a rabbit ileal loop assay and their genetic profiles were compared by PFGE. The environmental strains varied in their virulence phenotype and showed no-clonal relationships. The clinical strains were highly enterotoxic, hemolytic, proteolytic and showed indistinguishable PFGE profiles, although they differed in their cytotoxic activity. This is the first description, using cell culture and “in vivo” studies, of the virulence properties of non-O1 non-O139 V. cholerae from Argentina.
En este trabajo se analizó la presencia y expresión de genes de virulencia en V. cholerae no-O1 no-O139 de origen clínico y ambiental, aislados en Córdoba, Argentina. La mayoría de las cepas estudiadas contiene los genes toxR y hlyA, pero no ctxA, zot, ace, tcpA y stn. Se analizó la actividad hemolítica y citotóxica de estas cepas en los sobrenadantes de cultivo, así como su potencial enterotóxico en ensayos de asa ileal ligada de conejo. Además, los aislamientos fueron comparados por sus perfiles genéticos en PFGE. Las cepas del medio ambiente mostraron variación en su fenotipo de virulencia y no mostraron relación clonal. Las cepas clínicas fueron muy enterotóxicas, hemolíticas, proteolíticas y mostraron perfiles indistinguibles de PFGE, aunque mostraron diferencias en su actividad citotóxica. En este trabajo se describen por primera vez, utilizando ensayos de cultivo celular e “in vivo”, propiedades de virulencia de V. cholerae no-O1 no-O139 aislados en Argentina.
Subject(s)
Animals , Humans , Rabbits , Vibrio cholerae non-O1/pathogenicity , Argentina/epidemiology , Bacterial Typing Techniques , Bacterial Proteins/genetics , Bacterial Proteins/isolation & purification , Bacterial Proteins/physiology , Chlorocebus aethiops , COS Cells/microbiology , Cholera Toxin/genetics , DNA, Bacterial/genetics , Drug Resistance, Bacterial , Diarrhea/epidemiology , Diarrhea/microbiology , Electrophoresis, Gel, Pulsed-Field , Enterotoxins/genetics , Enterotoxins/isolation & purification , Enterotoxins/physiology , Gene Deletion , Genes, Bacterial , Hemolysin Proteins/genetics , Hemolysin Proteins/isolation & purification , Hemolysin Proteins/physiology , Metalloendopeptidases/genetics , Metalloendopeptidases/isolation & purification , Metalloendopeptidases/physiology , Phylogeny , Vibrio Infections/epidemiology , Vibrio Infections/microbiology , Vibrio cholerae non-O1/drug effects , Vibrio cholerae non-O1/genetics , Vibrio cholerae non-O1/isolation & purification , Virulence/genetics , Water MicrobiologyABSTRACT
Se realizó un estudio para conocer la frecuencia de enterotoxinas termolábil (LTh) y termoestable (STa) en cepas de Escherichia coli aisladas de heces de 300 cerdos de 1 a 10 días de edad que cursaron con un cuadro diarreico. Se aisló E. coli en el 100 por ciento de los animales muestreados. Mediante la técnica de ELISA, se detectó la producción de enterotoxina termoestable (STa) en 35 animales (11.6 por ciento). No se encontraron cepas de E. coli productoras de enterotoxina termolábil (LTh). Se recomienda la utilización de antisuero homólogo al realizar la técnica de GM1-ELISA debido a que existen diferencias inmunológicas entre la LT humana (LTh) y la LT porcina (LTp)
Subject(s)
Animals , Swine/microbiology , Enzyme-Linked Immunosorbent Assay/veterinary , Diarrhea/veterinary , Enterotoxins/physiology , Escherichia coli/isolation & purification , Immune SeraABSTRACT
Invasive properties of 15 strains of thermotolerant Campylobacter (12 C. jejuni and 3 C. coli) were studied using HeLa cells cultures. In four of them (3 C. jejuni and 1 C. coli), randomly selected, intestinal perfusion experiments were conducted in order to asses enterotoxigenicity. All strains were able to invade HeLa cells. The number of invaded HeLa cells ranged from 3 to 46 percent. In addition to their invasive properties, the 4 strains used in perfusion experiments were able to induce either a net secretory flux or an impaired sodium transport
Subject(s)
Animals , Cats , Dogs , Humans , Campylobacter coli/pathogenicity , Campylobacter jejuni/pathogenicity , Enterotoxins/physiology , HeLa CellsABSTRACT
To know at what age infants begin to excrete entertoxçigenic Eschirichia coli from feces, we studied 30 infants belonging to low socioeconomic status during the first 3 months of life, taking 11 samples of feces from each infant, beginning at the day of birth. We detected LT and ST enterotoxins of E. coli using ELISA test. From the samples studied, 34 samples from 21 (70 per cent) infants were positive for LT. In four samples (1.2 per cent), the presence of LT-producing E. coli coincided with diarrhea, corresponding to three (10.0 per cent) from the infants studied. The earliest age that we observed LT-producing E. coli was day 0 (day of birth). We did not find ST + o LT/ST-producing E. coli strains. We concluded that ETEC strains are frequents findings in healthy infants, and its presence is too early in persons of low socioeconomic status