Toxinas de Clostridium perfringens / Toxins of Clostridium perfringens

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.

[Toxins of Clostridium perfringens]. / Toxinas de clostridium perfringens.

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.

Detection of bovine viral diarrhoea virus (BVDV) nucleic acid and antigen in different organs of water buffaloes (Bubalus bubalis).

Bovine viral diarrhoea virus (BVDV) is a pestivirus that infects mainly bovine cattle. Nevertheless, there are several reports about infections in other members of the Artiodactyla order including serological studies, that indicate infection of BVDV in buffaloes. The aim of this article is to study the presence of BVDV in three young water buffaloes, displaying nonspecific clinical signs, compatible with the BVDV infection. Both immunohistochemistry and RT-PCR confirmed the presence of BVDV in the animals. The sequence analysis on RT-PCR amplicons revealed high identity with reference strains of genotypes 1a and 1b. Although BVDV was unequivocally identified in the sick animals, it has not been proved it is responsible for the clinical signs. Further studies are needed to clarify the pathogenic role of BVDV infection in this animal species, and the role of buffaloes in the epidemiology of BVDV infection.

The pathology of peracute experimental Clostridium perfringens type D enterotoxemia in sheep.

The pathological findings in sheep with peracute experimental Clostridium perfringens type D enterotoxemia are described. Of 16 animals inoculated intraduodenally with a whole culture of this microorganism and a starch solution in the abomasum, 12 developed clinical signs including increased respiratory efforts, recumbency, paddling, bleating, convulsions, blindness, and opisthotonus. Diarrhea was not observed in any of the animals. The time lapse between the beginning of intraduodenal infusion and onset of clinical signs varied between 30 minutes and 26 hours, and the clinical course varied between 1 and 9 hours. Gross postmortem changes were observed in these 12 animals and included pulmonary edema; excess pericardial, peritoneal, or pleural fluid with or without strands of fibrin; liquid small intestinal contents; leptomeningeal edema; cerebellar coning; and subcapsular petechiae on kidneys. Histological changes consisted of severe edema of pleura and interlobular septa and around blood vessels and airways and acidophilic, homogeneous, proteinaceous perivascular edema in the brain. Five of 12 animals (42%) with clinical signs consistent with enterotoxemia lacked specific histological lesions in the brain. None of the intoxicated or control animals developed nephrosis. Glucose was detected in the urine of 3 of 6 animals that were tested for this analyte. These results stress the importance of the use of histological examination of the brain, coupled with epsilon toxin detection, for a definitive diagnosis of C. perfringens type D enterotoxemia in sheep.

Ovine pulmonary adenomatosis in Patagonia, Argentina.

An outbreak of pulmonary adenomatosis (OPA) occurred in sheep in Patagonia, Argentina's southernmost region. On the affected farm, nine animals died over a 6-month period with pulmonary lesions of OPA. In all cases, the histology of the lungs was characterized by proliferation of cuboideal and prismatic cells lining the alveoli. Inflammatory exudates and accumulation of alveolar macrophages were marked in most cases, but in six of the cases there was no excess fluid in the airways. The presence of the Jaagsiekte retrovirus was demonstrated in the lungs by immunocytochemistry and PCR. To the best of our knowledge, this is the first report of OPA in Patagonia.

Malignant oedema associated with navel infection in a Merino lamb

Este relato descreve um caso de edema maligno associado com infecçäo do umbigo em um cordeiro merino de três dias de idade. Após necropsia, Clostridium chauvoei e Clostridium novyi foram detectados pela técnica de imunofluorescência direta (IFD) em impressöes obtidas do tecido subcutâneo do umbigo

Malignant oedema associated with blood-sampling in sheep.

Malignant oedema is a fatal disease of several animal species, produced by one or more members of the Clostridium genus. We report here a case of malignant oedema in a 1-year-old Friesian sheep after a blood sample was collected from the jugular vein. Clostridium septicum and Clostridium sordellii were isolated from the lesions and also demonstrated by a fluorescent antibody test. This report stresses the need for maintaining a clean environment for animals and for strict hygienic measures during procedures that generate wounds, together with immunity acquired by proper vaccination, for prevention of malignant oedema.

Effects of intravenous injection of Clostridium perfringens type D epsilon toxin in calves.

In cattle, a neurological lesion similar to that produced in sheep and goats by Clostridium perfringens type D enterotoxaemia has been reported. However, no causal relationship has been established between this disease and the lesion in cattle. The effects of single and multiple intravenous injections of epsilon toxin in three calves aged 6 months were studied. A further calf was inoculated intravenously with saline solution and used as a control. Epsilon toxin invariably produced neurological signs within 2-60 min of the end of the injection process. Clinical signs consisted of loss of consciousness, recumbency, convulsions, paddling, opisthotonus, hyperaesthesia and dyspnoea. Gross changes consisted of severe acute pulmonary oedema, which was particularly marked in the interlobular septa. The histological lesions consisted of intra-alveolar and interstitial oedema of the lung and variable degrees of perivascular proteinaceous oedema in the internal capsule, thalamus and cerebellar white matter. No clinical or post-mortem changes were observed in the control calf. These results show that calves are susceptible to the intravenous injection of epsilon toxin, and that they can show at least some of the histological lesions produced in sheep and goats by this toxin.

Hemochromatosis and celiac sprue. Case report.

The patient presented with apparent hemochromatosis and celiac sprue, a unique combination not previously reported. Almost all patients with celiac sprue have an iron deficiency which is usually present very early, often antedating other manifestations of the condition.

Teratological assessment of five oxidative hair dyes in the rat.

The oxidative dyes, 4,4'-diaminodiphenylene sulfate, N'-(2-hydroxyethyl)-4-nitro-O-phenylenediamine, N,N-dimethyl-p-phenylenediamine, 2,3-dihydroxynaphthalene, and resorcinol, were evaluated for teratogenic potential. Dyes were administered by gavage to pregnant Sprague-Dawley rats on gestation Days 6 through 15 at doses ranging from 12.5 to 500 mg/kg. No overt signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during the treatment period at the high dose for 4,4'-diaminodiphenylene sulfate, N'-(2-hydroxyethyl)-4-nitro-O-phenylenediamine, and 2,3-dihydroxynaphthalene. The high dose for N,N-dimethyl-p-phenylenediamine and resorcinol, which exceeded a 100-fold exaggeration of human exposure, did not produce a significant reduction in maternal weight gain. An evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye-treated and vehicle control groups. Administration of 100,000 units of vitamin A, the positive control, on Day 9 of gestation resulted in a significant increase in abnormal fetuses.

A quantitative in vitro assay for the evaluation of phototoxic potential of topically applied materials.

A quantitative in vitro method for phototoxic evaluation of chemicals has been developed and validated. The assay uses Saccharomyces cerevisiae, seeded in an agar overlay on top of a plate count agar base. 8-Methoxy psoralen is used as a reference standard against which materials are measured. Activity is quantified by cytotoxicity measured as zones of inhibition. Several known phototoxins (heliotropine, lyral, phantolid, and bergamot oil) and photoallergens (6-methyl coumarin and musk ambrette) are used to validate the assay. An excellent correlation is observed between in vivo studies employing Hartley albino guinea pigs and the in vitro assay for several fragrance raw materials and other chemicals. The in vitro assay exhibits a greater sensitivity from 2-500 fold. For three fragrance oils, the in vitro assay detects low levels of photobiological activity while the in vivo assay is negative. Although the in vitro assay does not discriminate between phototoxins and photoallergens, it can be used for screening of raw materials so that reduction in animal usage can be achieved while maintaining the protection of the consumer.

Evaluation of the teratogenic potential of the oxidative dyes 6-chloro-4-nitro-2-aminophenol and o-chloro-p-phenylenediamine.

The oxidative dyes 6-chloro-4-nitro-2-aminophenol and o-chloro-p-phenylenediamine were administered by gavage to Sprague-Dawley rats on days 6-15 of gestation at dose levels of 87.5, 175 and 350 mg 6-chloro-4-nitro-2-aminophenol/kg body weight/day and 100, 200 and 400 mg o-chloro-p-phenylenediamine/kg/day. Maternal body-weight gain was significantly reduced by the high dose of each dye and the intermediate dose of o-chloro-p-phenylenediamine. Rats given the high dose of the latter dye showed a significant increase in resorptions and a significant decrease in foetal body weights. No embryotoxic or foetotoxic effects were observed with 6-chloro-4-nitro-2-aminophenol. Evaluation of foetuses for gross, visceral and skeletal anomalies revealed no statistically significant differences between dye-treated and vehicle-control groups but showed a significant increase (to 25-91%) in the incidence of abnormal foetuses in the group exposed to vitamin A, the positive control.

Evaluation of the toxicity and carcinogenicity of hair dyes in Swiss mice.

The chronic toxicologic and carcinogenic potential of two oxidative and twelve non-oxidative hair dyes has been evaluated. The dyes were skin painted up to 3 times weekly on groups of 60 male and 60 female Eppley Swiss mice. Treatments were carried out for 20 months followed by terminal sacrifice. Nine months after treatments were initiated an intermediate sacrifice of ten mice per sex per group was carried out. Body weights and survival differed little between appropriate male and female treatment and control groups. Differences between treated and control groups in absolute and relative liver and kidney weights and in hematological and urinary values were not considered to be indicative of toxicologic effects. Microscopic examinations of the skin revealed occasional hyperplasia, necrosis, ulceration and other lesions not significantly increased by dye treatment. Chronic inflammation of the skin was observed in the control and treated mice and was significantly increased by one non-oxidative dye. The predominant tumors diagnosed were liver hemangioma, lung adenoma and malignant lymphoma. There was a statistically significant increase in the incidence of malignant lymphoma in female mice in 3 treated groups when compared to control group 2, but the differences were not significant when these groups were compared to control group 1. In addition the values in these 3 groups were within the range of control values for this tumor in female mice in the Eppley colony. No other tumors occurred at significantly increased frequencies in treated mice. We conclude that toxicological and carcinogenic effects were not clearly induced by the hair dye formulations.

Evaluation of the teratogenic potential of the oxidative dye N-phenyl-para-phenylenediamine.

The oxidative dye N-phenyl-para-phenylenediamine was evaluated for teratogenic potential. The dye was administered by gavage to pregnant Sprague-Dawley rats at dose levels of 50, 100, and 200 mg/kg on gestation days six through fifteen. No signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during treatment at the high dose level of 200 mg/kg. The test material did not produce embryotoxic nor fetal toxic effects at dose levels utilized. Evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye treated and control groups. Oral exposure of dams to the positive control, Vitamin A, resulted in a significant increase in the number of litters with fetuses having external, visceral, and skeletal anomalies.

Teratological assessment of the oxidative dye 4-methyl-N-ethylamino phenol sulfate.

The oxidative dye 4-methyl-N-ethylamino phenol sulfate was evaluated for teratogenic potential. The dye was administered by gavage to pregnant Sprague-Dawley rats at dose levels of 300, 600, and 1200 mg/kg on gestation days six through fifteen. No signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during treatment at the high dose level of 1200 mg/kg. The test material did not produce embryotoxic nor fetal toxic effects at dose levels utilized. Evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye treated and control groups. Oral exposure of dams to the positive control, Vitamin A, resulted in a significant increase in the number of litters with abnormal fetuses.