Sudden death in sheep associated with Clostridium sordellii

Detection and molecular characterization of Clostridium perfringens, Paeniclostridium sordellii and Clostridium septicum from lambs and goat kids with hemorrhagic abomasitis in Turkey

BACKGROUND

The pathogenic Clostridia cause neurotoxic, histotoxic and enterotoxic infections in humans and animals. Several Clostridium species have been associated with abomasitis in ruminants. The present study aimed to investigate the frequency, and the presence of virulence genes, of Clostridium perfringens, Paeniclostridium sordellii and Clostridium septicum in lambs and goat kids with hemorrhagic abomasitis.

RESULTS

A total of 38 abomasum samples, collected from lambs and goat kids of 1 week to 1 month of age in different farms located in eastern Turkey between 2021 and 2022, were evaluated by histopathology, culture and PCR. At necropsy, the abomasum of the animals was excessively filled with caseinized content and gas, and the abomasum mucosa was hemorrhagic in varying degrees. In histopathological evaluation, acute necrotizing hemorrhagic inflammation was noted in abomasum samples. The examination of swab samples by culture and PCR revealed that C. perfringens type A was the most frequently detected species (86.84%) either alone or in combination with other Clostridium species. P. sordellii, C. perfringens type F and C. septicum were also harboured in the samples, albeit at low rates. Beta2 toxin gene (cpb2) was found in three of C. perfringens type A positive samples.

CONCLUSION

It was suggested that vaccination of pregnant animals with toxoid vaccines would be beneficial in terms of protecting newborn animals against Clostridial infections. This study investigated the presence of clostridial toxin genes in abomasal samples for the first time in Turkey.

Alterations in the Gut Microbial Composition and Diversity of Tibetan Sheep Infected With Echinococcus granulosus

Hydatidosis/cystic echinococcosis (CE) caused by Echinococcus granulosus is a parasitic zoonotic disease worldwide, threatening animal health and production and public health safety. However, it is still unclear that whether E. granulosus infection can result in the alteration of gut microbiota in Tibetan sheep. Therefore, a study was designed to investigate the influences of E. granulosus infection on gut microbiota of Tibetan sheep. A total of 10 ovine small intestinal contents (five from healthy and five from infected) were obtained and subjected to high-throughput sequencing by MiSeq platform. A total of 2,395,641 sequences and 585 operational taxonomic units (OTUs) were identified. Firmicutes and Proteobacteria were the most dominant phyla in all samples. Moreover, the proportions of Armatimonadetes and Firmicutes in the infected Tibetan sheep were significantly decreased, whereas Actinobacteria, Chloroflexi, and Acidobacteria had significantly increased. At the genus level, the Christensenellaceae_R-7_group and Ruminococcaceae_NK4A214_group were the predominant bacterial genera in all the samples. Furthermore, the healthy Tibetan sheep exhibited higher abundances of Intestinimonas, Butyrivibrio, Pseudobutyrivibrio, Ruminococcaceae, Eubacterium_coprostanoligenes_group, Oxobacter, Prevotella_1, Ruminiclostridium_6, Coprococcus_1, Ruminococcus, Lachnospiraceae_UCG-002, Olsenella, and Acetitomaculum, whereas Kocuria, Clostridium_sensu_stricto_1, Slackia, Achromobacter, and Stenotrophomonas levels were lower. In conclusion, our results conveyed an information that E. granulosus infection may cause an increase in pathogenic bacteria and a decrease in beneficial bacteria. Additionally, a significant dynamical change in gut microbiota could be associated with E. granulosus infection.

Grazing and Supplementation of Dietary Yeast Probiotics Shape the Gut Microbiota and Improve the Immunity of Black Fattening Goats (Capra hircus)

This study aimed to investigate the effects of different feeding modes on the growth performance, gut microbiota, and immunity of Black Fattening Goat (Capra hircus). A total of 30 goats were grouped in three groups by their feeding modes (pasture grazing group, PG; barn feeding group, BF; barn feeding + probiotics, BF + P; n = 10) and the study was performed for 114 days. After a 2-week adaptation period, the first growth performance test was conducted, and the blood and fecal samplings (day 0) were collected on January 17, 2020, while the second and third test and samplings were conducted on days 53 and 100 of feeding. The species-composition of fecal microbiota was analyzed by 16S ribosomal RNA gene-sequencing using PacBio single molecule real time (SMRT) sequencing technology. Both the BF and BF + P groups had the highest (P < 0.05) body’s weight and length, and chest circumference at days 53 and 100, especially at day 100, the body’s weight of both the BF groups were more than 18 kg. The levels of immunoglobulin A (IgA) and immunoglobulin G (IgG) were found to be significantly higher (P < 0.05) in the PG and BF + P groups at day 100. The PG group exhibited the highest number of operational taxonomic unit (OTUs) and alpha diversity. Firmicutes, Bacteroidetes, and Verrucomicrobia were the predominant phyla in all the fecal samples. The relative abundance of Akkermansia muciniphila and Ruminococcus flavefaciens were found to be significantly higher (P < 0.05) in PG group and BF + P group at day 100, respectively, which might partially explain the significantly higher (P < 0.05) levels of IgA and IgG in these two groups. These findings suggested that BF supplemented with 5 g probiotics (Saccharomyces cerevisiae and mannan oligosaccharides) per day has the potential to enhance the growth and immunity of Black Fattening Goats.

Comparative analysis of microbial community structure between healthy and Aeromonas veronii-infected Yangtze finless porpoise

Background

The gut microbiota is a complex ecosystem, which is essential for the metabolism, health and immunity of host. Many diseases have been shown to be closely related to the alteration of intestinal flora. Aeromonas veronii as a conditioned pathogen can cause disease in Yangtze finless porpoise through intestinal infections. However, it is not clear whether the disease caused by Aeromonas veronii is related to changes of intestinal flora. In the current study, the diversity and composition of gut microbiota in the healthy and Aeromonas veronii-infected Yangtze finless porpoise were evaluated by high-throughput sequencing to further investigate the potential association between intestinal flora alteration and pathogen invasion.

Results

A total of 127,3276 high-quality sequences were achieved and 2465 operational taxonomic units (OTUs) were in common among all samples. The results of alpha diversity showed that there was no obvious difference in richness and diversity between healthy and Aeromonas veronii-infected Yangtze finless porpoise. Firmicutes, Bacteroidetes and Proteobacteria were the most dominant phyla in all samples. In addition, the healthy Yangtze finless porpoise exhibited higher abundance of Firmicutes and Fusobacteria than Aeromonas veronii-infected Yangtze finless porpoise, while, the level of Proteobacteria was decreased. At the genus level, Paeniclostridium and Paraclostridium were the predominant bacteria genera in the CK (healthy Yangtze finless porpoise) group. In the DIS (Aeromonas veronii-infected Yangtze finless porpoise) group, Lactobacillus and unidentified_Enterobacteriaceae were the dominant bacteria genera and the proportion of Paeniclostridium, Paraclostridium, Terrisporobacter, Cetobacterium, Candidatus Arthromitus, Terrabacter and Dechloromonas were reduced.

Conclusions

In conclusion, our results showed that Aeromonas veronii infection can alter the gut microbiota of the Yangtze finless porpoise by affecting the number of harmful bacteria and beneficial bacteria.

Fatal Clostridium sordellii-mediated hemorrhagic and necrotizing gastroenteropathy in a dog: case report

BACKGROUND

Canine hemorrhagic gastroenteritis (also canine gastrointestinal hemorrhagic syndrome) is commonly associated with Clostridium perfringens, although in some cases the etiology remains unclear. This report describes a fatal acute hemorrhagic and necrotizing gastroenteropathy in a dog associated with Clostridium sordellii, a bacterial species never before identified as the etiological agent of hemorrhagic and necrotizing gastroenteropathy in dogs.

CASE PRESENTATION

A fully vaccinated, eight-year-old, female neutered Labrador presented with a history of vomiting without diarrhea. Clinical examination revealed pink mucous membranes, adequate hydration, normothermia, and normocardia. The dog was discovered deceased the following day. Post-mortem examination showed moderate amounts of dark red, non-clotted fluid within the stomach that extended into the jejunum. Discoloration was noted in the gastric mucosa, liver, lungs, and kidneys, with small petechial hemorrhages present in the endocardium over the right heart base and thymic remnants. Histological analysis demonstrated that the gastric fundic mucosa, the pyloric region, small intestine, and large intestine exhibited superficial coagulative necrosis and were lined with a layer of short Gram-positive rods. Anaerobic culture of the gastric content revealed C. sordellii as the dominant bacterial species and neither Salmonella spp., Campylobacter spp., C. perfringens, nor C. difficile were isolated. Unexpectedly, whole genome sequencing of the C. sordellii isolate showed that it lacked the main plasmid-encoded virulence factors typical of the species, indicating that the genetic determinants of pathogenicity of this strain must be chromosomally encoded. Further phylogenetic analysis revealed it to be genetically similar to C. sordellii isolates associated with gastroenteric disease in livestock, indicating that the infection may have been acquired from the environment.

CONCLUSIONS

This case demonstrates that C. sordellii can associate with a canine hemorrhagic and necrotizing gastroenteropathy in the absence of C. perfringens and illustrates the benefits of using bacterial whole genome sequencing to support pathological investigations in veterinary diagnostics. These data also update the molecular phylogeny of C. sordellii, indicating a possible pathogenic clade in the environment that is distinct from currently identified clades.

Paeniclostridium (Clostridium) sordellii-associated enterocolitis in 7 horses

Enteric disease in horses may be caused by a variety of microorganisms, including several clostridial species. Paeniclostridium sordellii (previously Clostridium sordellii) has been frequently associated with gas gangrene in humans and several animal species, including horses. However, its role in enteric diseases of animals has not been fully determined. We describe herein 7 cases of enteric disease in horses associated with P. sordellii infection. Grossly, the small and/or large intestines were necrotic, hemorrhagic, and edematous. Microscopically, there was severe mucosal necrosis and hemorrhage of the small and/or large intestine of all horses. P. sordellii was isolated and/or demonstrated by immunohistochemistry and/or PCR in the intestine of all horses. All other known causes of enteric disease in horses were ruled out in these 7 cases. P. sordellii should be considered among the differential diagnoses in cases of enteric disease in horses.

Dynamic Distribution of Gut Microbiota in Goats at Different Ages and Health States

The importance of the gut microbiota (GM) of animals is widely acknowledged because of its pivotal roles in metabolism, immunity, and health maintenance. The level of health can be reflected by the dynamic distribution of GM. In this study, high-throughput sequencing of the bacterial 16S rRNA gene was used to compare the microbial populations from feces in healthy and diarrheic kids, which reflected the dynamic shift of microbiota in kids and investigated differences from adult healthy goats. Healthy kids and goats not only displayed higher species richness but also exhibited higher bacterial diversity than diarrheic kids based on the results of the operational taxonomic unit analysis, alpha diversity, and beta diversity. Firmicutes and Bacteroidetes were the most dominant phyla in all samples. At the genus level, the differences in diversity and abundance between diarrheic kids and the other two groups were gradually observed. In the diarrheic kid intestine, Bacteroides remained the dominant species, and the proportion of Clostridium_sensu_stricto_1 and Paeniclostridium increased, whereas Rikenellaceae_RC9_gut_group, Ruminococcaceae_UCG-005, and Christensenellaceae_R-7_group were significantly reduced. The results showed the differences of GM in diarrheic kids and healthy kids were significant while in kids and goats were not obvious. Differences in the composition of intestinal microbiota may not be the cause of diarrhea, and some changes of bacterial richness may guide our interpretation of diarrhea. This study is the first to investigate the distribution of GM in Boer goats with different ages and health states. Furthermore, this study will provide a theoretical basis for the establishment of a prevention and treatment system for goat diarrhea.

Clostridium sordellii outer spore proteins maintain spore structural integrity and promote bacterial clearance from the gastrointestinal tract

Bacterial spores play an important role in disease initiation, transmission and persistence. In some species, the exosporium forms the outermost structure of the spore and provides the first point of contact between the spore and the environment. The exosporium may also be involved in spore adherence, protection and germination. Clostridium sordellii is a highly lethal, spore forming pathogen that causes soft-tissue infections, enteritis and toxic-shock syndrome. Despite the importance of C. sordellii spores in disease, spore proteins from this bacterium have not been defined or interrogated functionally. In this study, we identified the C. sordellii outer spore proteome and two of the identified proteins, CsA and CsB, were characterised using a genetic and phenotypic approach. Both proteins were essential for the correct formation and positioning of the C. sordellii spore coat and exosporium. The absence of CsA reduced sporulation levels and increased spore sensitivity to heat, sodium hydroxide and hydrochloric acid. By comparison, CsB was required for normal levels of spore adherence to cervical, but not vaginal, cells, with csB mutant spores having increased adherence properties. The establishment of a mouse infection model of the gastrointestinal tract for C. sordellii allowed the role of CsA and CsB to be interrogated in an infected host. Following the oral administration of spores to mice, the wild-type strain efficiently colonized the gastrointestinal tract, with the peak of bacterial numbers occurring at one day post-infection. Colonization was reduced by two logs at four days post-infection. By comparison, mice infected with the csB mutant did not show a reduction in bacterial numbers. We conclude that C. sordellii outer spore proteins are important for the structural and functional integrity of spores. Furthermore, outer spore proteins are required for wild-type levels of colonization during infection, possibly as a result of the role that the proteins play in spore structure and morphology.

Abomasal and Third Compartment Ulcers in Ruminants and South American Camelids

Abomasal ulcers are frequent incidental findings in necropsies of domestic ruminants and South American Camelids (SAC) or in slaughter animals and are a frequent cause of death in the most affected group of cattle, veal calves. Their true prevalence and significance is unknown owing to limitations in diagnosing the condition in live animals. This article discusses types of ulcers, possible causes of ulceration, and the clinical consequences, symptoms, and differential diagnoses, as well as further diagnostics in cattle, small ruminants and SAC. The limited treatment options and possibilities for prevention are reviewed.

Structural Characterization of Clostridium sordellii Spores of Diverse Human, Animal, and Environmental Origin and Comparison to Clostridium difficile Spores

Clostridium sordellii is a significant pathogen with mortality rates approaching 100%. It is the bacterial spore that is critical in initiating infection and disease. An understanding of spore structures as well as spore morphology across a range of strains may lead to a better understanding of C. sordellii infection and disease. However, the structural characteristics of the C. sordellii spores are limited. In this work, we have addressed this lack of detail and characterized the C. sordellii spore morphology. The use of traditional and advanced microscopy techniques has provided detailed new observations of C. sordellii spore structural features, which serve as a reference point for structural studies of spores from other bacterial species.

Clostridium sordellii is an often-lethal bacterium causing human and animal disease. Crucial to the infectious cycle of C. sordellii is its ability to produce spores, which can germinate into toxin-producing vegetative bacteria under favorable conditions. However, structural details of the C. sordellii spore are lacking. Here, we used a range of electron microscopy techniques together with superresolution optical microscopy to characterize the C. sordellii spore morphology with an emphasis on the exosporium. The C. sordellii spore is made up of multiple layers with the exosporium presenting as a smooth balloon-like structure that is open at the spore poles. Focusing on the outer spore layers, we compared the morphologies of C. sordellii spores derived from different strains and determined that there is some variation between the spores, most notably with spores of some strains having tubular appendages. Since Clostridium difficile is a close relative of C. sordellii, their spores were compared by electron microscopy and their exosporia were found to be distinctly different from each other. This study therefore provides new structural details of the C. sordellii spore and offers insights into the physical structure of the exosporium across clostridial species.

IMPORTANCEClostridium sordellii is a significant pathogen with mortality rates approaching 100%. It is the bacterial spore that is critical in initiating infection and disease. An understanding of spore structures as well as spore morphology across a range of strains may lead to a better understanding of C. sordellii infection and disease. However, the structural characteristics of the C. sordellii spores are limited. In this work, we have addressed this lack of detail and characterized the C. sordellii spore morphology. The use of traditional and advanced microscopy techniques has provided detailed new observations of C. sordellii spore structural features, which serve as a reference point for structural studies of spores from other bacterial species.

Infection of Internal Umbilical Remnant in Foals by Clostridium sordellii

Omphalitis and the resulting septicemia contribute to perinatal mortality in several animal species. In foals, the most important causes of omphalitis are Escherichia coli and Streptococcus zooepidemicus. However to date, no information has been published about the role of Clostridium sordellii in these infections. In this paper, we describe 8 cases of perinatal mortality in foals associated with internal umbilical remnant infection by C. sordellii. The foals studied were between 12 and 21 days old at the time of death, and various breeds were represented in the group. Five of the foals were male and 3 were female. The diagnosis was established on the basis of the detection of C. sordellii by 3 methods (culture, fluorescent antibody test, and immunohistochemistry) and on gross and histopathologic findings. All foals had acute peritonitis, and the internal umbilical remnant was thickened by edema, hemorrhage, and fibrosis. A moderate amount of serosanguinous fluid with fibrin strands was present in the pericardial sac and pleural cavity. Histopathologically, the urachus and umbilical arterial walls were thickened by edema and exhibited hemorrhage, fibrin, and leukocytic infiltration. Gram-positive bacterial rods were observed in subepithelial areas of the urachus, the adventicia of umbilical arteries, and interstitium of the internal umbilical remnant. On the basis of these findings, we suggest that C. sordellii should be considered in the differential diagnosis for infections of the internal umbilical remnant in foals.

Sudden Death Associated with Clostridium sordellii in Captive Lions (Panthera leo)

In the spring of 2003, a series of sudden deaths in a group of adult lions ( Panthera leo) with a previous history of depression, inanition, and lethargy, was investigated. Five animals died within 24 to 36 hours after onset of signs of disease. Serologic screening for viral disease detection was negative, evidence of parasites was not detected, and results of a complete blood count and serum biochemical analysis were within reference intervals in all lions. The most relevant lesions observed were multiple areas of necrosis and hemorrhage in the intestinal outer muscular layer, and cellulitis with an intense bloody edema in the mesenteric and the pericardial fat tissue. On the basis of the fulminant course of the disease, the gross and histologic findings, and the isolation and identification of Clostridium sordellii, a diagnosis of infectious myositis and cellulitis associated with acute clostridiosis was made. To the authors' knowledge, this is the first report of sudden death associated with C. sordellii in felines.

The Sialidase NanS Enhances Non-TcsL Mediated Cytotoxicity of Clostridium sordellii

The clostridia produce an arsenal of toxins to facilitate their survival within the host environment. TcsL is one of two major toxins produced by Clostridium sordellii, a human and animal pathogen, and is essential for disease pathogenesis of this bacterium. C. sordellii produces many other toxins, but the role that they play in disease is not known, although previous work has suggested that the sialidase enzyme NanS may be involved in the characteristic leukemoid reaction that occurs during severe disease. In this study we investigated the role of NanS in C. sordellii disease pathogenesis. We constructed a nanS mutant and showed that NanS is the only sialidase produced from C. sordellii strain ATCC9714 since sialidase activity could not be detected from the nanS mutant. Complementation with the wild-type gene restored sialidase production to the nanS mutant strain. Cytotoxicity assays using sialidase-enriched culture supernatants applied to gut (Caco2), vaginal (VK2), and cervical cell lines (End1/E6E7 and Ect1/E6E7) showed that NanS was not cytotoxic to these cells. However, the cytotoxic capacity of a toxin-enriched supernatant to the vaginal and cervical cell lines was substantially enhanced in the presence of NanS. TcsL was not the mediator of the observed cytotoxicity since supernatants harvested from a TcsL-deficient strain displayed similar cytotoxicity levels to TcsL-containing supernatants. This study suggests that NanS works synergistically with an unknown toxin or toxins to exacerbate C. sordellii-mediated tissue damage in the host.

Comparative genomic and phenomic analysis of Clostridium difficile and Clostridium sordellii, two related pathogens with differing host tissue preference

Background

Clostridium difficile and C. sordellii are two anaerobic, spore forming, gram positive pathogens with a broad host range and the ability to cause lethal infections. Despite strong similarities between the two Clostridial strains, differences in their host tissue preference place C. difficile infections in the gastrointestinal tract and C. sordellii infections in soft tissues.

Results

In this study, to improve our understanding of C. sordellii and C. difficile virulence and pathogenesis, we have performed a comparative genomic and phenomic analysis of the two. The global phenomes of C. difficile and C. sordellii were compared using Biolog Phenotype microarrays. When compared to C. difficile, C. sordellii was found to better utilize more complex sources of carbon and nitrogen, including peptides. Phenotype microarray comparison also revealed that C. sordellii was better able to grow in acidic pH conditions. Using next generation sequencing technology, we determined the draft genome of C. sordellii strain 8483 and performed comparative genome analysis with C. difficile and other Clostridial genomes. Comparative genome analysis revealed the presence of several enzymes, including the urease gene cluster, specific to the C. sordellii genome that confer the ability of expanded peptide utilization and survival in acidic pH.

Conclusions

The identified phenotypes of C. sordellii might be important in causing wound and vaginal infections respectively. Proteins involved in the metabolic differences between C. sordellii and C. difficile should be targets for further studies aimed at understanding C. difficile and C. sordellii infection site specificity and pathogenesis.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1663-5) contains supplementary material, which is available to authorized users.

Clostridium sordellii genome analysis reveals plasmid localized toxin genes encoded within pathogenicity loci

Background

Clostridium sordellii can cause severe infections in animals and humans, the latter associated with trauma, toxic shock and often-fatal gynaecological infections. Strains can produce two large clostridial cytotoxins (LCCs), TcsL and TcsH, related to those produced by Clostridium difficile, Clostridium novyi and Clostridium perfringens, but the genetic basis of toxin production remains uncharacterised.

Results

Phylogenetic analysis of the genome sequences of 44 strains isolated from human and animal infections in the UK, US and Australia placed the species into four clades. Although all strains originated from animal or clinical disease, only 5 strains contained LCC genes: 4 strains contain tcsL alone and one strain contains tcsL and tcsH. Four toxin-positive strains were found within one clade. Where present, tcsL and tcsH were localised in a pathogenicity locus, similar to but distinct from that present in C. difficile. In contrast to C. difficile, where the LCCs are chromosomally localised, the C. sordellii tcsL and tcsH genes are localised on plasmids. Our data suggest gain and loss of entire toxigenic plasmids in addition to horizontal transfer of the pathogenicity locus. A high quality, annotated sequence of ATCC9714 reveals many putative virulence factors including neuraminidase, phospholipase C and the cholesterol-dependent cytolysin sordellilysin that are highly conserved between all strains studied.

Conclusions

Genome analysis of C. sordellii reveals that the LCCs, the major virulence factors, are localised on plasmids. Many strains do not contain the LCC genes; it is probable that in several of these cases the plasmid has been lost upon laboratory subculture. Our data are consistent with LCCs being the primary virulence factors in the majority of infections, but LCC-negative strains may precipitate certain categories of infection. A high quality genome sequence reveals putative virulence factors whose role in virulence can be investigated.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1613-2) contains supplementary material, which is available to authorized users.

Foot infection by Clostridium sordellii: case report and review of 15 cases in France

We report a case of foot infection by Clostridium sordellii and review 15 human infections registered at a Reference Center in France during the period 1998 to 2011. All strains were found nontoxigenic, lacking the lethal toxin gene coding for TcsL. Like Clostridium septicum, several C. sordellii infections were associated with intestinal neoplasms.

Clostridium sordellii in a brown bear (Ursus arctos) from Spain

Clostridium sordellii is found in the environment and occasionally in animal (including human) intestines and may cause myonecrosis and large outbreaks of enterotoxemia. A few cases of fatal clostridial infection in bears (Ursus spp.) have been described worldwide but none attributed to C. sordellii. We describe a fatal case of septicemia caused by C. sordellii in an illegally trapped brown bear (Ursus arctos). At necropsy, acute gangrenous myositis was the primary lesion. Serohemorrhagic edema was observed in the abdominal cavity, thorax, pericardium, and skeletal muscle, mostly affecting femoral, humeral, and scapular muscles. Hemorrhage was observed in the heart, skeletal muscles, stomach, and intestine. Liver, spleen, and kidney appeared with loss of consistency, hemorrhages, and edema. Microscopically, primary lesions were in skeletal muscle, stomach, and small intestine, with gram-positive, clostridial-like bacilli. Biochemical and molecular tests identified C. sordellii in cultures from liver, muscle, and intestine. Sequences showed a homology of >99% with the 16S rRNA gene sequence of C. sordellii. The severity of effects of the C. sordellii infection reveal the importance of this pathogen as a wildlife health risk with conservation concerns, as well as the need to consider possible infection with this pathogen in management actions involving immobilization, stress, or severe muscular activity of wild brown bears.

Identification and characterization of Clostridium sordellii toxin gene regulator

Toxigenic Clostridium sordellii causes uncommon but highly lethal infections in humans and animals. Recently, an increased incidence of C. sordellii infections has been reported in women undergoing obstetric interventions. Pathogenic strains of C. sordellii produce numerous virulence factors, including sordellilysin, phospholipase, neuraminidase, and two large clostridial glucosylating toxins, TcsL and TcsH. Recent studies have demonstrated that TcsL toxin is an essential virulence factor for the pathogenicity of C. sordellii. In this study, we identified and characterized TcsR as the toxin gene (tcsL) regulator in C. sordellii. High-throughput sequencing of two C. sordellii strains revealed that tcsR lies within a genomic region that encodes TcsL, TcsH, and TcsE, a putative holin. By using ClosTron technology, we inactivated the tcsR gene in strain ATCC 9714. Toxin production and tcsL transcription were decreased in the tcsR mutant strain. However, the complemented tcsR mutant produced large amounts of toxins, similar to the parental strain. Expression of the Clostridium difficile toxin gene regulator tcdR also restored toxin production to the C. sordellii tcsR mutant, showing that these sigma factors are functionally interchangeable.

Clinical, microbiological and histological findings in lambs affected by 'salivary abomasum disease'

'Salivary abomasum disease' is a common syndrome in Greece affecting lambs and kids from three to 17 days of age. In this case series, we present clinical and laboratory findings from 37 affected lambs presented alive and subsequently euthanased for welfare reasons and necropsied, and also from 24 other lambs submitted dead that were also necropsied. The clinical signs in the 37 lambs presented alive included lethargy (100 per cent), absence of sucking (83.8 per cent), weakness (37.8 per cent), abdominal distension (40.5 per cent) and increased frequency of urination (24.3 per cent). Diarrhoea was not observed in any affected lambs. At necropsy of these 37 lambs, the abomasum was distended with gas (70.3 per cent), saliva (43.2 per cent) along with mixed milk clots and gastric secretions; while multiple small mucosal and serosal haemorrhages with blood clots ('coffee grains') were recorded (91.9 per cent). Eight of 37 lambs that were examined alive, had elevated blood urea nitrogen concentrations (21.6 per cent). The pH of the abomasal contents ranged from 1.0 to 2.8; Escherichia coli was cultured from six of 37 (16.2 per cent) abomasal fluid samples. A mild to moderate inflammatory cell infiltrate was present in the mucosal lamina propria of 13 of 15 abomasal samples (86.6 per cent). Kidneys were paler than normal in 13 of the total 61 lambs necropsied (21.3 per cent); while acute tubular necrosis was evident on histopathological examination of 11 of 12 examined pale kidneys (91.6 per cent). The low abomasal pH and reported successful treatment with oral sodium bicarbonate suggest that metabolic acidosis may develop during the disease; however, further studies, including blood gas analysis, and determination of D- and L-lactic acid concentrations, are necessary to confirm this hypothesis.

Gynecologic clostridial toxic shock in women of reproductive age

Clostridial toxic shock, caused by Clostridium sordellii or Clostridium perfringens, is a rare and largely fatal syndrome among reproductive-aged women with genital tract infection, and may occur following various pregnancy outcomes or without pregnancy. Clinicians should be aware of common clinical features of this very rapidly-progressing syndrome including abdominal pain, tachycardia, hypotension, third-space fluid accumulations, hemoconcentration, and marked leukemoid response, often with lack of fever. In this review, we summarize known cases through mid-2011 and information on clinical presentation, diagnosis, treatment, and results of recent investigations regarding pathogenesis, including germination, toxins, and host response that may have important implications for development of preventive or therapeutic interventions.

Rho/Ras-GTPase-dependent and -independent activity of clostridial glucosylating toxins

Clostridial glucosylating toxins are the main virulence factors of clostridia responsible for gangrene and/or colitis. These toxins have been well characterized to inactivate Rho/Ras-GTPases through glucosylation. However, the signalling pathways downstream of Rho/Ras-GTPases leading to the intracellular effects of these toxins are only partially known. Rac-dependent modification of focal adhesion complexes and phosphoinositide metabolism seem to be key processes involved in actin filament depolymerization and disorganization of intercellular junctions. In addition, clostridial glucosylating toxins induce Rho/Ras-independent intracellular effects such as activation of mitogen-activated protein kinase pathways, which are used by some of these toxins to trigger an inflammatory response.

Control of important clostridial diseases of sheep

Clostridia cause many different diseases, all characterized by sudden death, most occurring worldwide. Diseases caused by clostridia can be divided into 4 groups: those affecting the alimentary system (the enterotoxemias), those affecting the parenchymatous organs, those causing myonecrosis and toxemia, and those causing neurologic disorders. Their mode of action is to produce one or more potent toxins when multiplying under favorable conditions. Considerable variation exists between different strains of the same organism. Specific trigger factors are required to induce toxin production. Excellent control is obtained by the use of toxoid vaccines. Protection is passed to the lamb via the colostrum.

TcsL is an essential virulence factor in Clostridium sordellii ATCC 9714

Clostridium sordellii is an important pathogen of humans and animals, causing a range of diseases, including myonecrosis, sepsis, and shock. Although relatively rare in humans, the incidence of disease is increasing, and it is associated with high mortality rates, approaching 70%. Currently, very little is known about the pathogenesis of C. sordellii infections or disease. Previous work suggested that the lethal large clostridial glucosylating toxin TcsL is the major virulence factor, but a lack of genetic tools has hindered our ability to conclusively assign a role for TcsL or, indeed, any of the other putative virulence factors produced by this organism. In this study, we have developed methods for the introduction of plasmids into C. sordellii using RP4-mediated conjugation from Escherichia coli and have successfully used these techniques to insertionally inactivate the tcsL gene in the reference strain ATCC 9714, using targetron technology. Virulence testing revealed that the production of TcsL is essential for the development of lethal infections by C. sordellii ATCC 9714 and also contributes significantly to edema seen during uterine infection. This study represents the first definitive identification of a virulence factor in C. sordellii and opens the way for in-depth studies of this important human pathogen at the molecular level.

Functional implications of lethal toxin-catalysed glucosylation of (H/K/N)Ras and Rac1 in Clostridium sordellii-associated disease

Clostridium sordellii-based diseases in humans and livestock rely on the activity of the major virulence factors, the single-chain protein toxins TcsL and TcsH, both belonging to the large clostridial glucosylating toxins. TcsL exclusively glucosylates Rho and Ras low molecular weight GTP-binding proteins. TcsL-induced loss of barrier function in epithelial (diarrhoea) and endothelial cells (extravasation of blood fluid) is based on Rac glucosylation whereas induction of apoptosis results from glucosylation of Ras. Intracellular glucosylation of Rac and Ras can be tracked by immunoblot applying the glucosylation-sensitive antibodies Rac1(Mab 102) and Ras(Mab 27H5). Induction of apoptosis especially of phagocytotic cells is crucial for the severity of C. sordellii-associated disease. The inhibition of TcsL-induced apoptosis by tauroursodeoxycholic acid (TUDCA) may be a promising therapeutic option.

Heat resistance of Clostridium sordellii spores

The thermal destruction kinetics of Clostridium sordellii spores was studied in this research. Decimal reduction times (D values) for C. sordellii ATCC 9714 spores ranged between 175.60 min for D(80) (the D value for spore suspensions treated at 80 degrees C) and 11.22 min for D(95). The thermal resistance (Z) and temperature coefficient (Q(10)) values of spores were calculated to be as high as 12.59 degrees C and 6.23, respectively. At 95 degrees C, the relative thermal death rate and relative thermal death time of C. sordellii ATCC 9714 spores were found to be 0.0085/min and 118 min, respectively, indicating that the death rate of spores was 118 times lower at 95 degrees C than at 121.1 degrees C. Heat treatments at up to 85 degrees C for 120 min failed to cause a 100-fold destruction in spore populations of C. sordellii ATCC 9714. By contrast, spore counts were reduced by 2 log(10) cycles within 73 min and 23 min at 90 degrees C and 95 degrees C, respectively. This is the first published report of thermal inactivation of C. sordellii spores; however, further studies are needed to confirm these results in real food samples.

Clostridial toxins

Clostridia produce the highest number of toxins of any type of bacteria and are involved in severe diseases in humans and other animals. Most of the clostridial toxins are pore-forming toxins responsible for gangrenes and gastrointestinal diseases. Among them, perfringolysin has been extensively studied and it is the paradigm of the cholesterol-dependent cytolysins, whereas Clostridium perfringens epsilon-toxin and Clostridium septicum alpha-toxin, which are related to aerolysin, are the prototypes of clostridial toxins that form small pores. Other toxins active on the cell surface possess an enzymatic activity, such as phospholipase C and collagenase, and are involved in the degradation of specific cell-membrane or extracellular-matrix components. Three groups of clostridial toxins have the ability to enter cells: large clostridial glucosylating toxins, binary toxins and neurotoxins. The binary and large clostridial glucosylating toxins alter the actin cytoskeleton by enzymatically modifying the actin monomers and the regulatory proteins from the Rho family, respectively. Clostridial neurotoxins proteolyse key components of neuroexocytosis. Botulinum neurotoxins inhibit neurotransmission at neuromuscular junctions, whereas tetanus toxin targets the inhibitory interneurons of the CNS. The high potency of clostridial toxins results from their specific targets, which have an essential cellular function, and from the type of modification that they induce. In addition, clostridial toxins are useful pharmacological and biological tools.

Sarcina-like bacteria associated with bloat in young lambs and calves

Sarcina species are fastidious Gram-positive anaerobic bacteria that occur in cubical packets of eight or more cells. In 2006 to 2007, they were associated with cases of acute abomasal bloat in young lambs and calves. Two incidents were in lambs aged three to six weeks that were found dead, with one or two cases in each of a group of 15 and 100 lambs. Three incidents were recorded in small groups of calves up to 10 days of age, two cases in each incident, with the calves found dead or dying after a short illness characterised by bloat. Their gross lesions included emphysema and oedema of the abomasal wall, mucosal hyperaemia and haemorrhage, and rupture of the abomasum. Histological lesions included abomasitis with congestion, haemorrhage, emphysema and oedema. Bacteria characteristic of Sarcina species were observed in sections associated with the superficial mucosa of these cases, but the bacteria were not detected in cultures.

Conformational changes and reaction of clostridial glycosylating toxins

The crystal structures of the catalytic fragments of 'lethal toxin' from Clostridium sordellii and of 'alpha-toxin' from Clostridium novyi have been established. Almost half of the residues follow the chain fold of the glycosyl-transferase type A family of enzymes; the other half forms large alpha-helical protrusions that are likely to confer specificity for the respective targeted subgroup of Rho proteins in the cell. In the crystal, the active center of alpha-toxin contained no substrates and was disassembled, whereas that of lethal toxin, which was ligated with the donor substrate UDP-glucose and cofactor Mn2+, was catalytically competent. Surprisingly, the structure of lethal toxin with Ca2+ (instead of Mn2+) at the cofactor position showed a bound donor substrate with a disassembled active center, indicating that the strictly octahedral coordination sphere of Mn2+ is indispensable to the integrity of the enzyme. The homologous structures of alpha-toxin without substrate, distorted lethal toxin with Ca2+ plus donor, active lethal toxin with Mn2+ plus donor and the homologous Clostridium difficile toxin B with a hydrolyzed donor have been lined up to show the geometry of several reaction steps. Interestingly, the structural refinement of one of the three crystallographically independent molecules of Ca2+-ligated lethal toxin resulted in the glucosyl half-chair conformation expected for glycosyl-transferases that retain the anomeric configuration at the C1'' atom. A superposition of six acceptor substrates bound to homologous enzymes yielded the position of the nucleophilic acceptor atom with a deviation of <1 A. The resulting donor-acceptor geometry suggests that the reaction runs as a circular electron transfer in a six-membered ring, which involves the deprotonation of the nucleophile by the beta-phosphoryl group of the donor substrate UDP-glucose.

Tympany, acidosis, and mural emphysema of the stomach in calves: report of cases and experimental induction

Necropsy of 4 neonatal calves with a peracute syndrome of abdominal distention, diarrhea, dehydration, shock, and death revealed abomasal tympany, marked edema, hemorrhage, and emphysema of ruminal and abomasal walls and histopathologic lesions characteristic of forestomach acidosis. The presence of acid damage and the production of substantial quantities of gas strongly suggested that the pathogenesis of the syndrome involved exuberant fermentation of intragastric substrate. This supposition led to attempts to experimentally induce the syndrome by dosing neonatal calves with an alimentary tract flora, followed by milk replacer supplemented with excessive fermentable carbohydrate (D-glucose and cornstarch). Two of the 5 calves thus treated developed a syndrome very similar to that observed in naturally affected calves. Literature suggests involvement of several Clostridial species, Sarcina spp., and possibly other microbes or a combination thereof to be involved in very similar syndromes. Therefore it is suggested that this complex of lesions and clinical signs is not dependent on a single etiologic agent. Rather, it is proposed that the natural occurrence of disease requires a quantity of highly fermentable substrate (starch, glucose, lactose, etc.) and a bacterial flora that is capable of rapidly fermenting that particular substrate with a resultant production of gas and acid.

Clostridium sordellii lethal toxin kills mice by inducing a major increase in lung vascular permeability

When intraperitoneally injected into Swiss mice, Clostridium sordellii lethal toxin reproduces the fatal toxic shock syndrome observed in humans and animals after natural infection. This animal model was used to study the mechanism of lethal toxin-induced death. Histopathological and biochemical analyses identified lung and heart as preferential organs targeted by lethal toxin. Massive extravasation of blood fluid in the thoracic cage, resulting from an increase in lung vascular permeability, generated profound modifications such as animal dehydration, increase in hematocrit, hypoxia, and finally, cardiorespiratory failure. Vascular permeability increase induced by lethal toxin resulted from modifications of lung endothelial cells as evidenced by electron microscopy. Immunohistochemical analysis demonstrated that VE-cadherin, a protein participating in intercellular adherens junctions, was redistributed from membrane to cytosol in lung endothelial cells. No major sign of lethal toxin-induced inflammation was observed that could participate in the toxic shock syndrome. The main effect of the lethal toxin is the glucosylation-dependent inactivation of small GTPases, in particular Rac, which is involved in actin polymerization occurring in vivo in lungs leading to E-cadherin junction destabilization. We conclude that the cells most susceptible to lethal toxin are lung vascular endothelial cells, the adherens junctions of which were altered after intoxication.

Clostridium sordellii infection: epidemiology, clinical findings, and current perspectives on diagnosis and treatment

Clostridium sordellii infections pose difficult clinical challenges and are usually fatal. Most commonly, these infections occur after trauma, childbirth, and routine gynecological procedures, but they have recently been associated with medically induced abortions and injection drug use. We report 2 fatal cases, one of which was associated with minor trauma, and the other of which was associated with normal childbirth, and we summarize the clinical features of 43 additional cases of reported C. sordellii infection. Of these 45 cases, 8 (18%) were associated with normal childbirth, 5 (11%) were associated with medically induced abortion, and 2 (0.4%) were associated with spontaneous abortion. The case-fatality rate was 100% in these groups. Ten (22%) of the C. sordellii infections occurred in injection drug users, and 50% of these patients died. Other cases of C. sordellii infection (in 19 patients [43%]) occurred after trauma or surgery, mostly in healthy persons, and 53% these patients died. Overall, the mortality rate was 69% (31 of 45 patients). Eighty-five percent of all patients with fatal cases died within 2-6 days of initial infection, and nearly 80% of fatal cases developed leukemoid reactions. Rapid diagnostic tests and improved treatments are needed to reduced the morbidity and mortality associated with this devastating infection.

Clostridium sordellii lethal toxin is maintained in a multimeric protein complex

Clostridium sordellii lethal toxin (TcsL) is distinct among large clostridial toxins (LCTs), as it is markedly reduced in its rate of intoxication at pH 8.0 yet is cytotoxic at pH 4.0. Results from the present study suggest that TcsL's slow rate of intoxication at pH 8.0 is linked to formation of a high-molecular-weight complex containing dissociable pH 4.0-sensitive polypeptides. The cytosolic delivery of TcsL's enzymatic domain by using a surrogate cell entry system resulted in cytopathic effect rates similar to those of other LCTs at pH 8.0, further indicating that rate-limiting steps occurred at the point of cell entry. Since these rate-limiting steps could be overcome at pH 4.0, TcsL was examined across a range of pH values and was found to dissociate into distinct 45- to 55-kDa polypeptides between pH 4.0 and pH 5.0. The polypeptides reassociated when shifted back to pH 8.0. At pH 8.0, this complex was resistant to sodium dodecyl sulfate (SDS) and multiple proteases; however, following dissociation, the polypeptides became protease sensitive. Dissociation of TcsL, and cytotoxicity, could be blocked by preincubation with ethylene glycol bis(sulfosuccinimidylsuccinate), resulting in cross-linking of the polypeptides. TcsL was also examined at pH 8.0 by using SDS-agarose gel electrophoresis and transmission electron microscopy and was found to exist in a higher-molecular-weight complex which resolved at a size exceeding 750 kDa and also dissociated at pH 4.0. However, this complex did not reassemble following a shift back to pH 8.0. Collectively, these data suggest that TcsL is maintained in a protease-resistant, high-molecular-weight complex, which dissociates at pH 4.0, leading to cytotoxicity.

pH-enhanced cytopathic effects of Clostridium sordellii lethal toxin

Clostridium sordellii lethal toxin (TcsL) is a large clostridial toxin (LCT) that glucosylates Ras, Rac, and Ral. TcsL differs from other LCTs because it modifies Ras, which does not cycle from cytosol to membrane. By using a suite of inhibitors, steps in cell entry by TcsL were dissected, and entry appears to be dependent on endosomal acidification. However, in contrast to TcdB, TcsL was substantially slower in its time course of entry. TcsL cytopathic effects (CPE) were blocked by bafilomycin A1 and neutralized by antiserum up to 2 h following treatment of cells with the toxin. The slow time course of intoxication and relatively high cytopathic dose were alleviated by exposing TcsL to acid pH, resulting in a time course similar to that of TcdB. The optimal pH range for activation was 4.0 to 5.0, which increased the rate of intoxication over 5-fold, lowered the minimal intoxicating dose by over 100-fold, and allowed complete substrate modification within 2 h, as shown by differential glucosylation. Fluorescence analysis of TcsL with 2-(p-toluidinyl) naphthalene-6-sulfonic acid as a probe suggested the acid pH stimulated a hydrophobic transition in the protein, a likely prelude to membrane insertion. Finally, acid entry by TcsL caused TcdB-like morphological changes in CHO cells, which suggesting that acid activation may impact substrate recognition profiles for TcsL.

The clinical spectrum of Clostridium sordellii bacteraemia: two case reports and a review of the literature

Clostridium sordellii is rarely associated with disease in humans. Since its first report in 1922 only a few cases of bacteraemia have been reported. This report describes two cases of C sordellii bacteraemia; the oldest and youngest patients reported to date. The first, is a previously well 81 year old woman presented with perianal infection, which was later complicated by thrombosis of the aorta, and the second is a 12 year old boy with epilepsy who presented with an ear infection. These cases are also highlighted to demonstrate the wide spectrum of presentation of sordellii bacteraemia.

Effects of iron dextran injections on the incidence of abomasal bloat, clinical pathology and growth rates in lambs

A preliminary study revealed significantly lower serum iron concentrations in lambs that developed abomasal bloat about one week later, than in lambs that did not develop bloat. In a subsequent trial, with 754 naturally reared twin lambs from five flocks, iron dextran injections were found to have a preventive effect on the development of abomasal bloat. Clinical signs of abomasal bloat were observed in the placebo-treated lamb of 16 couples and in the iron-treated lamb of six couples (P<0.05). In three further couples, both lambs developed bloat. The iron-treated group had significantly (P<0.001) better average weight gains, both from birth to summer, and from birth to autumn of approximately 0.5 and 1 kg, respectively. There was a reduction in red blood cell values and iron saturation in the placebo group 14 days after treatment but not in the iron-treated lambs. In one of the flocks, there was a decrease in the cumulative incidence of abomasal bloat from 37 per cent to 3 per cent during the period of four years after measures such as later lambing, earlier turnout and iron injections were introduced.

Sarcina -like bacteria, Clostridium fallax and Clostridium sordellii in lambs with abomasal bloat, haemorrhage and ulcers

A study of abomasal disease in lambs aged 2-5 weeks, made during the period 1993-1998, included 67 cases and 45 non-affected controls. Gross pathological findings included various combinations of bloat, haemorrhage and ulcers in the abomasum. Sarcina -like bacteria were found in sections and smears from the abomasum of 79% (53/67) of the cases. From one case, a lamb with abomasal bloat, the anaerobic "packet"-forming Sarcina ventriculi was cultivated from the abomasal contents and identified by biochemical reactions and sequencing of the 16S rRNA gene. Sarcina -like bacteria were observed microscopically in specimens from 94% (44/47) of the lambs with abomasal gas and in 45% (9/20) of those with ulcers or haemorrhage or both but little gas. On culture, abomasal contents from 41 cases yielded Clostridium fallax from 16 (39%) and Clostridium sordellii from eight (20%); abomasal cultures from 30 control lambs were negative for the three bacterial species. Quantitative cultivation, carried out on abomasal contents from live lambs and lambs dead </=3 h, showed that Clostridium perfringens, Escherichia coli and Lactobacillus spp. were present in the majority of both cases and controls, with no significant differences in the mean numbers.

Abomasal bloat, haemorrhage and ulcers in young Norwegian lambs

An abomasal syndrome affecting mainly three- to four-week-old lambs was studied by using a case-control design involving 88 cases and 85 controls. The principal clinical signs were tympany and colic. The cases were divided into three groups according to the main gross pathological findings in 82 of them. The 28 lambs in group 1 had abomasal tympany, the 29 lambs in group 2 had severe damage to the abomasal mucosa, and the 25 lambs in group 3 consisted mainly of lambs with various other diseases in combination with abomasal changes. The lambs in group 1 had a significantly (P<0.05) lower mean (se) abomasal pH (2.7 [0.19]) than those in group 2 (4.1 [0.32]), group 3 (3.7 [0.39]) or the controls (3.3 [0.13]). The ruminal pH values ranged from 3.5 to 7.4 but there were no significant differences between the groups. Lambs with ulcers had a significantly (P<0.05) higher frequency of trichophytobezoars, than the cases without ulcers or the controls. The tympanic lambs in group 1 had a significantly higher mean packed cell volume, and higher mean red and white blood cell counts, and a significantly lower mean cell volume and mean cell haemoglobin concentration than the healthy control lambs.