Human disease associated with Clostridium perfringens enterotoxin

Is anaerobic digestion a reliable barrier for deactivation of pathogens in biosludge?

As World Health Organization advocates, the global burden of sanitation related disease and access to safely managed sanitation and safely treated wastewater should be monitored strictly. However, the spread of pathogens through various agricultural applications or direct discharge of sewage sludge generated in municipal wastewater treatment plants poses a serious challenge on the environment and public health. Anaerobic digestion (AD), the principal method of stabilizing biosolids, can efficiently and largely deactivate viable pathogens, including parasite, virus, and the pathogens harboring antibiotic resistance genes. This review aims to provide a critical overview regarding the deactivation of sludge-associated pathogens by AD, through which a serious concern on the effectiveness and rationality of AD towards sludge pathogens control was raised. Meanwhile, the underlying deactivation mechanisms and affecting factors were all discussed, with the focus on pathogen-associated modeling, engineering design and technological aspects of AD. Lastly, a matric method incorporating the operating strategy of AD with the risk assessment was proposed for evaluating the reliability of AD-based pathogen deactivation, while the research agenda forward was also outlined.

A sandwich duplex immuno PCR for rapid and sensitive identification of Clostridium perfringens alpha and enterotoxin

The prevalence and lethality associated with C. perfringens alpha (CPA) and enterotoxin (CPE) toxaemia necessitate the need for rapid and definitive detection systems to initiate management measures. In the present study, a sandwich duplex immuno-capture PCR (SD-IPCR) was developed by employing IgY antibodies against a bivalent protein r-Cpae derived from CPA and CPE for antigen capture and reporter antibodies against truncated CPA or CPE conjugated to oligomers of distinguishable size for antigen revealing and signal amplification. The avian immunoglobulin's (IgY) were devoid of reactivity with S. aureus protein A (SpA), a commensal that often co-exists with C. perfringens. The assay was specific, had a detection limit (LOD) of 1 pg/ml for both CPA and CPE in PBS and improved the LOD by 10⁴ folds compared to an analogous sandwich ELISA with same set of antibodies. In spiking studies, a ten-fold reduction in LOD was observed in case of intestinal tissue samples (10 pg/ml) however, no change in LOD was observed when SD-IPCR was applied on to faecal, serum or muscle tissue samples. Of the 136 natural samples examined, the SD-IPCR could detect CPA and CPE in 29.4% and 35.3% samples, while the sandwich ELISAs could detect the same in 25.7% and 25% samples respectively owing to the relatively lesser sensitivity. The LOD and specificity of the SD-IPCR demonstrates its applicability as an efficient and rapid platform for direct detection CPA and CPE from diverse samples matrices in clinical microbiological and meat testing laboratories.

Effects of Bile Acids and Nisin on the Production of Enterotoxin by Clostridium perfringens in a Nutrient-Rich Medium

Clostridium perfringens is the second most common cause of bacterial foodborne illness in the United States, with nearly a million cases each year. C. perfringens enterotoxin (CPE), produced during sporulation, damages intestinal epithelial cells by pore formation, which results in watery diarrhea. The effects of low concentrations of nisin and bile acids on sporulation and toxin production were investigated in C. perfringens SM101, which carries an enterotoxin gene on the chromosome, in a nutrient-rich medium. Bile acids and nisin increased production of enterotoxin in cultures; bile acids had the highest effect. Both compounds stimulated the transcription of enterotoxin and sporulation-related genes and production of spores during the early growth phase. They also delayed spore outgrowth and nisin was more inhibitory. Bile acids and nisin enhanced enterotoxin production in some but not all other C. perfringens isolates tested. Low concentrations of bile acids and nisin may act as a stress signal for the initiation of sporulation and the early transcription of sporulation-related genes in some strains of C. perfringens, which may result in increased strain-specific production of enterotoxin in those strains. This is the first report showing that nisin and bile acids stimulated the transcription of enterotoxin and sporulation-related genes in a nutrient-rich bacterial culture medium.

Immunization with recombinant bivalent chimera r-Cpae confers protection against alpha toxin and enterotoxin of Clostridium perfringens type A in murine model

Clostridium perfringens type A, an anaerobic pathogen is the most potent cause of soft tissue infections like gas gangrene and enteric diseases like food poisoning and enteritis. The disease manifestations are mediated via two important exotoxins, viz. myonecrotic alpha toxin (αC) and enterotoxin (CPE). In the present study, we synthesized a bivalent chimeric protein r-Cpae comprising C-terminal binding regions of αC and CPE using structural vaccinology rationale and assessed its protective efficacy against both alpha toxin (αC) and enterotoxin (CPE) respectively, in murine model. Active immunization of mice with r-Cpae generated high circulating serum IgG (systemic), significantly increased intestinal mucosal s-IgA antibody titres and resulted in substantial protection to the immunized animals (100% and 75% survival) with reduced tissue morbidity when administered with 5×LD(100) doses of αC (intramuscular) and CPE (intra-gastric gavage) respectively. Mouse RBCs and Caco-2 cells incubated with a mixture of anti-r-Cpae antibodies and αC and CPE respectively, illustrated significantly higher protection against the respective toxins. Passive immunization of mice with a similar mixture resulted in 91-100% survival at the end of the 15 days observation period while mice immunized with a concoction of sham sera and respective toxins died within 2-3 days. This work demonstrates the efficacy of the rationally designed r-Cpae chimeric protein as a potential sub unit vaccine candidate against αC and CPE of C. perfringens type A toxemia.

Investigating an outbreak of Clostridium perfringens gastroenteritis in a school using smartphone technology, London, March 2013

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Enteropathogenic bacteria in dogs and cats: diagnosis, epidemiology, treatment, and control

This report offers a consensus opinion on the diagnosis, epidemiology, treatment, and control of the primary enteropathogenic bacteria in dogs and cats, with an emphasis on Clostridium difficile, Clostridium perfringens, Campylobacter spp., Salmonella spp., and Escherichia coli associated with granulomatous colitis in Boxers. Veterinarians are challenged when attempting to diagnose animals with suspected bacterial-associated diarrhea because well-scrutinized practice guidelines that provide objective recommendations for implementing fecal testing are lacking. This problem is compounded by similar isolation rates for putative bacterial enteropathogens in animals with and without diarrhea, and by the lack of consensus among veterinary diagnostic laboratories as to which diagnostic assays should be utilized. Most bacterial enteropathogens are associated with self-limiting diarrhea, and injudicious administration of antimicrobials could be more harmful than beneficial. Salmonella and Campylobacter are well-documented zoonoses, but antimicrobial administration is not routinely advocated in uncomplicated cases and supportive therapy is recommended. Basic practices of isolation, use of appropriate protective equipment, and proper cleaning and disinfection are the mainstays of control. Handwashing with soap and water is preferred over use of alcohol-based hand sanitizers because spores of C. difficile and C. perfringens are alcohol-resistant, but susceptible to bleach (1:10 to 1:20 dilution of regular household bleach) and accelerated hydrogen peroxide. The implementation of practice guidelines in combination with the integration of validated molecular-based testing and conventional testing is pivotal if we are to optimize the identification and management of enteropathogenic bacteria in dogs and cats.

Multilocus sequence typing subtypes of poultry Clostridium perfringens isolates demonstrate disease niche partitioning

Clostridium perfringens is a ubiquitous and versatile pathogenic bacterium and is implicated in the etiology of the poultry diseases necrotic enteritis (NE) and poultry gangrene (PG). In this study, multilocus sequence typing was used to investigate genotypic relationships among 139 C. perfringens isolates from 74 flocks. These isolates had multiple disease, host, and environmental origins. The results indicated a polymorphic yet highly clonal population, with 79.6% of all isolates partitioning into one of six clonal complexes or two dominant sequence types, ST-9 and ST-31. The most prolific clonal complex, CC-1, contained 27.3% of all isolates and was not clearly associated with one particular disease. The subtypes CC-4 and ST-31 were highly associated with NE and represented 9.4% and 7.2% of the total isolates, respectively. No PG-associated and NE-associated C. perfringens isolates shared the same sequence type or clonal complex. NE-associated subtypes were more clonal and appeared more evolutionarily divergent than PG-associated subtypes, which tended to cluster in the more ancestral lineages alongside isolates from asymptomatic chickens and turkeys. Toxin gene screening identified cpb2 throughout these isolates and correlated the presence of netB with NE pathology. Previous investigations into the genetic basis of C. perfringens pathogenicity have focused on toxins and other variable genetic elements. This study presents the first sequence-based comparison of C. perfringens isolates recovered in clinical cases of PG and NE and demonstrates that niche specialization is observable in the core genomes of poultry-associated C. perfringens isolates, a concept with both epidemiological and evolutionary significance.

Crystallization and preliminary crystallographic analysis of the Clostridium perfringens enterotoxin

Clostridium perfringens is a Gram-positive anaerobic species of bacterium that is notable for its ability to produce a plethora of toxins, including membrane-active toxins (alpha-toxins), pore-forming toxins (-toxins) and binary toxins (iota-toxins). Here, the crystallization of the full-length wild-type C. perfringens enterotoxin is reported, which is the causative agent of the second most prevalent food-borne illness in the United States and has been implicated in many other gastrointestinal pathologies. Several crystal forms were obtained. However, only two of these optimized crystal forms (I and II) were useable for X-ray diffraction data collection. The form I crystals diffracted to d(min) = 2.7 A and belonged to space group C2, while the form II crystals diffracted to d(min) = 4 A and belonged to space group P2(1)3.

Detection of Clostridium perfringens in yearling lamb meat (barbacoa), head, and gut tacos from public markets in Mexico City

No reports on the incidence of Clostridium perfringens in popularly-consumed food from Mexico City have been published; neither are there any reports that have analyzed food consumed in popular markets and less established restaurants. Therefore, this study is aimed at providing data to evaluate the relevance of C. perfringens as an etiologic agent of food-borne diseases. Of the 650 analyzed samples, 106 (16.3%) were positive for C. perfringens; 6.4% (16/250) isolates were from barbacoa, 19% (38/200) from head, and 13% (52/200) from gut tacos. The presence of C. perfringens in these popular-consumed foods demonstrates its relevance as an etiologic agent of food-borne diseases, and confirms the great sanitary risk involved in their consumption. These results may serve as a basis for the Mexican sanitary authorities to control the microbiological quality of street-made foods.

Analysis of core housekeeping and virulence genes reveals cryptic lineages of Clostridium perfringens that are associated with distinct disease presentations

Clostridium perfringens is an important human and animal pathogen that causes a number of diseases that vary in their etiology and severity. Differences between strains regarding toxin gene composition and toxin production partly explain why some strains cause radically different diseases than others. However, they do not provide a complete explanation. The purpose of this study was to determine if there is a phylogenetic component that explains the variance in C. perfringens strain virulence by assessing patterns of genetic polymorphism in genes (colA gyrA, plc, pfoS, and rplL) that form part of the core genome in 248 type A strains. We found that purifying selection plays a central role in shaping the patterns of nucleotide substitution and polymorphism in both housekeeping and virulence genes. In contrast, recombination was found to be a significant factor only for the virulence genes plc and colA and the housekeeping gene gyrA. Finally, we found that the strains grouped into five distinct evolutionary lineages that show evidence of host adaptation and the early stages of speciation. The discovery of these previously unknown lineages and their association with distinct disease presentations carries important implications for human and veterinary clostridial disease epidemiology and provides important insights into the pathways through which virulence has evolved in C. perfringens.

Necrotizing Enterocolitis Associated with Clostridium perfringens Type A in Previously Healthy North American Adults

BACKGROUND

Necrotizing enteritis associated with Clostridium perfringens type C ("pigbel") is a well-known syndrome in severely protein-deprived populations in the Pacific. It is exceedingly rare in the developed world. C perfringens type A is a common cause of acute gastroenteritis and, in a handful of infections, has been reported in association with a syndrome resembling necrotizing enteritis.

STUDY DESIGN

This study includes a case series and literature review. Charts and autopsy reports from four patients with adult necrotizing enterocolitis (ANEC) were reviewed. C perfringens isolates were subtyped by mouse bioassay and pulsed-field gel electrophoresis. Fixed tissue specimens were tested with an anticlostridial antibody using an immunohistochemical assay.

RESULTS

Between 2000 and 2003, ANEC developed in four previously healthy men; three died. The small bowel was affected in three patients and the colon in two patients. Portal or mesenteric vein thrombosis occurred in three patients. C perfringens type A was isolated from three patients and immunohistochemical assay demonstrated clostridial antigens limited to affected areas of the intestine of all four. The nonculture positive patient had a strong epidemiologic link to one of the others, and a compatible clinical course. C perfringens of the same pulsed-field gel electrophoresis-defined molecular subtyped was isolated from stool samples of one patient, his wife, and food from a restaurant they patronized.

CONCLUSIONS

ANEC associated with C perfringens type A infection occurred in four North American adults. Culture for C perfringens type A should be performed in cases of ANEC. Alternative tests such as immunohistochemical assay were diagnostically useful. Additional research might uncover virulence factors, host factors, and the burden of disease in the population.

Bacterial-associated diarrhea in the dog: a critical appraisal

The clinical documentation of enteropathogenic bacteria causing diarrhea in dogs is clouded by the presence of many of these organisms existing as normal constituents of the indigenous intestinal flora. The diagnosis of a putative bacterial enteropathogen(s) in dogs should be made based on a combination of parameters, including signalment and predisposing factors, clinical signs, serologic assays for toxins, fecal culture, and PCR. Relying on results of fecal culture alone is problematic, because C perfringens, C difficile, Campylobacter spp, and pathogenic and non-pathogenic E coli are commonly isolated from apparently healthy dogs [10,13,33]. Nevertheless, culture may be useful in procuring isolates for the application of molecular techniques, such as PCR, for detection of specific toxin genes or molecular typing of isolated strains to establish clonality in suspected outbreaks. The oversimplistic attempt to characterize bacterially associated diarrhea by anatomic localization of clinical signs should be discouraged, because most of the previously mentioned bacteria have been associated with small and large intestinal diarrhea. Accurate diagnosis of infections may require diagnostic laboratories to incorporate PCR-based assays using genus- and species-specific primers to facilitate detection of toxin genes and differentiation of species that appear phenotypically and biochemically similar. There has been tremendous interest in the application of microarray technology for the simultaneous detection of thousands of genes or target DNA sequences on one glass slide. This powerful tool could be used for detection of specific pathogenic bacterial strains in fecal specimens obtained from dogs in the future.

Anaerobic cellulitis as the result of Clostridium perfringens: a rare cause of vascular access graft infection

Infection of prosthetic vascular access grafts is the second most common complication of vascular access and represents a challenge encountered by the vascular surgeon. Anaerobic graft infections are rare. We report on a case of a prosthetic vascular access graft infection with Clostridium perfringens. To our knowledge, only one other case with an infected arteriovenous shunt caused by C perfringens has been reported. The patient, a 67-year-old woman with end-stage renal failure as the result of polycystic renal disease, was seen with an infected pseudoaneurysm at the arterial puncture site of the loop graft on the left arm. There was associated purulence at the time of operation. Surgical management consisted of complete graft removal because of the presence of small tunnel abscesses. C perfringens was found in the resected pseudoaneurysm and graft material. Infected pseudoaneurysms most likely are attributable to repetitive punctures in one small area and to a break in sterile technique. A compromised vascular supply, not infrequent in patients for hemodialysis, may lower the oxidation reduction potential, which allows anaerobic bacteria, such as C perfringens, to cause infection.

A probabilistic analysis of Clostridium perfringens growth during food service operations

The purpose of this study was threefold: first, the study was designed to illustrate the use of data and information collected in food safety surveys in a quantitative risk assessment. In this case, the focus was on the food service industry; however, similar data from other parts of the food chain could be similarly incorporated. The second objective was to quantitatively describe and better understand the role that the food service industry plays in the safety of food. The third objective was to illustrate the additional decision-making information that is available when uncertainty and variability are incorporated into the modelling of systems.