Diversity of Clostridium perfringens toxin-genotypes from dairy farms

Prevalence, toxin-genotype distribution, and transmission of Clostridium perfringens from the breeding and milking process of dairy farms

This study aimed to elucidate the distribution, transmission, and cross-contamination of Clostridium perfringens during the breeding and milking process from dairy farms. The prevalence of 22.3% (301/1351) yielded 494 C. perfringens isolates; all isolates were type A, except for one type D, and 69.8% (345/494) of the isolates carried atyp. cpb2 and only 0.6% (3/494) of the isolates carried cons. cpb2. C. perfringens detected throughout the whole process but without type F. 150 isolates were classified into 94 pulsed-field gel electrophoresis (PFGE) genotypes; among them, six clusters contained 34 PFGE genotypes with 58.0% isolates which revealed epidemic correlation and genetic diversity; four PFGE genotypes (PT57, PT9, PT61, and PT8) were the predominant genotypes. The isolates from different farms demonstrated high homology. Our study confirmed that C. perfringens demonstrated broad cross-contamination from nipples and hides of dairy cattle, followed by personnel and tools and air-introduced raw milk during the milking process. In conclusion, raw milk could serve as a medium for the transmission of C. perfringens, which could result in human food poisoning. Monitoring and controlling several points of cross-contamination during the milking process are essential as is implementing stringent hygiene measures to prevent further spread and reduce the risk of C. perfringens infection.

Genetic diversity and phylogenetic relationships of Clostridium perfringens strains isolated from mastitis and enteritis in Egyptian dairy farms

BACKGROUND

Clostridium perfringens, a common environmental bacterium, is responsible for a variety of serious illnesses including food poisoning, digestive disorders, and soft tissue infections. Mastitis in lactating cattle and sudden death losses in baby calves are major problems for producers raising calves on dairy farms. The pathogenicity of this bacterium is largely mediated by its production of various toxins.

RESULTS

The study revealed that Among the examined lactating animals with a history of mastitis, diarrheal baby calves, and acute sudden death cases in calves, C. perfringens was isolated in 23.5% (93/395) of the total tested samples. Eighteen isolates were obtained from mastitic milk, 59 from rectal swabs, and 16 from the intestinal contents of dead calves. Most of the recovered C. perfringens isolates (95.6%) were identified as type A by molecular toxinotyping, except for four isolates from sudden death cases (type C). Notably, C. perfringens was recovered in 100% of sudden death cases compared with 32.9% of rectal swabs and 9% of milk samples. This study analyzed the phylogeny of C. perfringens using the plc region and identified the plc region in five Egyptian bovine isolates (milk and fecal origins). Importantly, this finding expands the known data on C. perfringens phospholipase C beyond reference strains in GenBank from various animal and environmental sources.

CONCLUSION

Phylogenetic analyses of nucleotide sequence data differentiated between strains of different origins. The plc sequences of Egyptian C. perfringens strains acquired in the present study differed from those reported globally and constituted a distinct genetic ancestor.

Moringa oleifera as a potential antimicrobial against pathogenic Clostridium perfringens isolates in farm animals

Background

Clostridium perfringens (CP) is an emerging anaerobic pathogen that can aggravate severe fatal infections in different hosts and livestock.

Aim

This paper was designed to monitor the antibacterial efficacy of Moringa oleifera (M. oleifera) plant against different CP isolates of variant toxin genotypes comparing that with commercial antibiotics in the veterinary field.

Methods

A total of 200 examined fecal, intestinal, and liver samples from cattle, sheep, and goats were investigated bacteriologically and biochemically for CP. Then, the isolates were examined by polymerase chain reaction (PCR) for toxin gene typing. Thereafter, the antimicrobial susceptibility testing as well as the antibacterial efficacy of M. oleifera were evaluated and statistically analyzed against recovered isolates.

Results

The prevalence rate of CP was 51% (102/200); of which 54.5% was from cattle, 50% from sheep, and 40% from goat. Moreover, all CP isolates were highly resistant to tetracycline and lincomycin drugs; meanwhile, they were of the least resistance against ciprofloxacin (8.3%-16.7%), cefotaxime (16.7%-25%), and gentamycin (26.7%-33.3%). For M. oleifera, high antibacterial efficacy with greater inhibition zones of the plant was recorded with its oil (20-24 mm) and ethanolic extracts (16-20 mm) against CP than the aqueous extract (≤ 10 mm). A good correlation was stated between M. oleifera oil and toxin type of CP isolates particularly type A followed by D and B types. Interestingly, the oil and ethanolic extracts of M. oleifera gave higher antibacterial efficacy than most commercial antibiotics against the recovered isolates.

Conclusion

This study highlighted the potent antibacterial properties of M. oleifera for suppressing CP isolated from farm animals; hence, more investigations on M. oleifera are suggested to support its use as a medical herbal plant substituting antibiotics hazards and resistance problems worldwide.

Clostridium perfringens-Opportunistic Foodborne Pathogen, Its Diversity and Epidemiological Significance

The C. perfringens species is associated with various environments, such as soils, sewage, and food. However, it is also a component of the gastrointestinal (GI) microflora (i.e., microbiota) of sick and healthy humans and animals. C. perfringens is linked with different systemic and enteric diseases in livestock and humans, such as gas gangrene, food poisoning, non-foodborne diarrhoea, and enterocolitis. The strains of this opportunistic pathogen are known to secrete over 20 identified toxins that are considered its principal virulence factors. C. perfringens belongs to the anaerobic bacteria community but can also survive in the presence of oxygen. The short time between generations, the multi-production capability of toxins and heat-resistant spores, the location of many virulence genes on mobile genetic elements, and the inhabitance of this opportunistic pathogen in different ecological niches make C. perfringens a very important microorganism for public health protection. The epidemiological evidence for the association of these strains with C. perfringens-meditated food poisoning and some cases of non-foodborne diseases is very clear and well-documented. However, the genetic diversity and physiology of C. perfringens should still be studied in order to confirm the importance of suspected novel virulence traits. A very significant problem is the growing antibiotic resistance of C. perfringens strains. The aim of this review is to show the current basic information about the toxins, epidemiology, and genetic and molecular diversity of this opportunistic pathogen.

Identification and Characterization of Clostridium perfringens Atypical CPB2 Toxin in Cell Cultures and Field Samples Using Monoclonal Antibodies

A direct sandwich enzyme-linked immunosorbent assay (sELISA) was developed for the detection of the atypical β2-toxin (CPB2) of Clostridium perfringens. Polyclonal (PAbs) and monoclonal (MAbs) antibodies were previously obtained employing recombinant CPB2 produced in the baculovirus system as antigen. In the current study, PAbs were used as capture molecules, while purified MAbs conjugated to horseradish peroxidase (MAbs-HRP) were used for the detection of atypical CPB2 toxin. MAbs 5C11E6 and 2G3G6 showed high reactivity, sensitivity and specificity when tested on 232 C. perfringens cell culture isolates. In addition, a reactivity variation among different strains producing atypical CPB2 toxin was observed using the conformation-dependent MAb 23E6E6, suggesting the hypothesis of high instability and/or the existence of different three-dimensional structures of this toxin. Results obtained by sELISA and Western blotting performed on experimentally CPB2-contaminated feces revealed a time-dependent proteolytic degradation as previously observed with the consensus allelic form of CPB2. Finally, the sELISA and an end-point PCR, specific for the atypical cpb2 gene, were used to test field samples (feces, rectal swabs and intestinal contents) from different dead animal species with suspected or confirmed clostridiosis. The comparison of sELISA data with those obtained with end-point PCR suggests this method as a promising tool for the detection of atypical CPB2 toxin.

A global phylogenomic and metabolic reconstruction of the large intestine bacterial community of domesticated cattle

BACKGROUND

The large intestine is a colonization site of beneficial microbes complementing the nutrition of cattle but also of zoonotic and animal pathogens. Here, we present the first global gene catalog of cattle fecal microbiomes, a proxy of the large intestine microbiomes, from 436 metagenomes from six countries.

RESULTS

Phylogenomics suggested that the reconstructed genomes and their close relatives form distinct branches and produced clustering patterns that were reminiscent of the metagenomics sample origin. Bacterial taxa had distinct metabolic profiles, and complete metabolic pathways were mainly linked to carbohydrates and amino acids metabolism. Dietary changes affected the community composition, diversity, and potential virulence. However, predicted enzymes, which were part of complete metabolic pathways, remained present, albeit encoded by different microbes.

CONCLUSIONS

Our findings provide a global insight into the phylogenetic relationships and the metabolic potential of a rich yet understudied bacterial community and suggest that it provides valuable services to the host. However, we tentatively infer that members of that community are not irreplaceable, because similar to previous findings, symbionts of complex bacterial communities of mammals are expendable if there are substitutes that can perform the same task. Video Abstract.

Clostridium perfringens associated with dairy farm systems show diverse genotypes

Clostridium perfringens is a bacterial species of importance to both public and animal health. Frequently found in food system environments, it presents a risk to food animal health such as dairy herds, and may cross contaminate associated ingredients or food products, with potential to cause sporadic and outbreaks of disease in human populations, including gastroenteric illness. In this study, we characterized C. perfringens isolated from bovine, caprine, and ovine dairy farm systems (n = 8, 11 and 4, respectively). Isolates were phenotypically screened for antimicrobial sensitivity profiling, and subjected to whole genome sequencing to elucidate related genetic markers, as well as examine virulence gene markers, mobile genetic elements, and other features. Both toxin type A and type D isolates were identified (78 % and 22 % of isolates, respectively), including 20 novel sequence types. Resistance to clindamycin was most prevalent among antibiotics screened (30 %), followed by erythromycin (13 %), then penicillin and tetracycline (4 %), although an additional 3 isolates were non-susceptible to tetracycline. Most isolates harboured plasmids, which mobilised virulence markers such as etx, cpb2, and resistance markers tetA(P), tetB(P), and erm(Q), on conjugative plasmids. The presence of type D isolates on caprine farms emphasizes the need for control efforts to prevent infection and potential enterotoxemia. Clostridium perfringens enterotoxin (cpe) was not identified, suggesting lower risk of gastrointestinal illness from contaminated foods, the presence of other virulence and antimicrobial resistance markers suggests farm hygiene remains an important consideration to help ensure food safety of associated dairy foods produced.

Infection Dynamics of Clostridium perfringens Fingerprinting in Buffalo and Cattle of Punjab Province, Pakistan

Clostridium perfringens produces core virulence factors that are responsible for causing hemorrhagic abomasitis and enterotoxemia making food, animals, and humans susceptible to its infection. In this study, C. perfringens was isolated from necropsied intestinal content of buffalo and cattle belonging to four major bovine-producing regions in the Punjab Province of Pakistan for the purpose offind out the genetic variation. Out of total 160 bovine samples (n: 160), thirty-three (n: 33) isolates of C. perfringens were obtained from buffalo (Bubales bubalis) and cattle (Bos indicus) that were further subjected to biochemical tests; 16S rRNA based identification and toxinotyping was done using PCR (Polymerase Chain Reaction) and PFGE (Pulse Field Gel Electrophoresis) pulsotypesfor genetic diversity. Occurrence of C. perfringens was found to be maximum in zone-IV (Bhakkar and Dera Ghazi Khan) according to the heatmap. Correlation was found to be significant and positive among the toxinotypes (α-toxin, and ε-toxin). Response surface methodology (RSM) via central composite design (CCD) and Box-Behnken design (BBD) demonstrated substantial frequency of C. perfringens based toxinotypes in all sampling zones. PFGE distinguished all isolates into 26 different pulsotypes using SmaI subtyping. Co-clustering analysis based on PFGE further decoded a diversegenetic relationship among the collected isolates. This study could help us to advance toward disease array of C. perfringens and its probable transmission and control. This study demonstrates PFGE patterns from Pakistan, and typing of C. perfringens by PFGE helps illustrate and mitigate the incidence of running pulsotypes.

Phenotypic and Genotypic Characterization of C. perfringens Isolates from Dairy Cows with a Pathological Puerperium

Clostridium perfringens (C. perfringens) forms part of the intestinal microbiome, but is also a known pathogen in histotoxic infections. The significance of the pathogen as a cause of uterine infections in cattle has been little studied so far. Here, we analyzed the association between a pathological puerperium in cattle and the detection of C. perfringens in a prospective longitudinal study. Clostridium perfringens were only found in vaginal and uterine samples of diseased cattle, and were absent in healthy controls. Isolates (n = 21) were tested for the production of major toxins (alpha-, beta-, epsilon-toxin) by ELISA and for the potential of production of major (alpha-, beta-, iota-toxin) and minor toxins (beta2 toxin) by PCR. Furthermore, antimicrobial susceptibility was also tested phenotypically by microdilution. Despite the frequent use of tetracycline treatment in cows suffering from puerperal disorders, no isolate showed phenotypic tetracycline resistance. Most isolates did not release major amounts of toxin. The strict association of C. perfringens with puerperal disease, together with the absence of major toxins might hint towards a major role of other or unknown clostridial virulence factors in uterine disease.

Toxigenic Profile of Clostridium perfringens Strains Isolated from Natural Ingredient Laboratory Animal Diets

Clostridium perfringens is an anaerobic, gram-positive, spore-forming bacterium that ubiquitously inhabits a wide varietyof natural environments including the gastrointestinal tract of humans and animals. C. perfringens is an opportunistic enteropathogen capable of producing at least 20 different toxins in various combinations. Strains of C. perfringens are currentlycategorized into 7 toxinotypes (A, B, C, D, E, F, and G) based on the presence or absence of 6 typing-toxins (α, β, epsilon, iota, enterotoxin, and netB). Each toxinotype is associated with specific histotoxic and enteric diseases. Spontaneous enteritis due to C. perfringens has been reported in laboratory animals; however, the source of the bacteria was unknown. The Quality Assurance Laboratory (QAL) at the National Institute of Environmental Health Sciences (NIEHS) routinely screens incoming animal feeds for aerobic, enteric pathogens, such as Salmonella spp. and E. coli. Recently, QAL incorporated anaerobic screening of incoming animal feeds. To date, the lab has isolated numerous Clostridium species, including C. perfringens, from 23 lots ofnatural ingredient laboratory animal diets. Published reports of C. perfringens isolation from laboratory animal feeds couldnot be found in the literature. Therefore, we performed a toxin profile screen of our isolated strains of C. perfringens usingPCR to determine which toxinotypes were present in the laboratory animal diets. Our results showed that most C. perfringens strains we isolated from the laboratory animal feed were toxinotype A with most strains also possessing the theta toxin. Two of the C. perfringens strains also possessed the β toxin. Our results demonstrated the presence of C. perfringens in nonsterile, natural ingredient feeds for laboratory animals which could serve as a source of this opportunistic pathogen.

FI: The Fecobiome Initiative

Animal husbandry has been key to the sustainability of human societies for millennia. Livestock animals, such as cattle, convert plants to protein biomass due to a compartmentalized gastrointestinal tract (GIT) and the complementary contributions of a diverse GIT microbiota, thereby providing humans with meat and dairy products. Research on cattle gut microbial symbionts has mainly focused on the rumen (which is the primary fermentation compartment) and there is a paucity of functional insight on the intestinal (distal end) microbiota, where most foodborne zoonotic bacteria reside. Here, we present the Fecobiome Initiative (or FI), an international effort that aims at facilitating collaboration on research projects related to the intestinal microbiota, disseminating research results, and increasing public availability of resources. By doing so, the FI can help mitigate foodborne and animal pathogens that threaten livestock and human health, reduce the emergence and spread of antimicrobial resistance in cattle and their proximate environment, and potentially improve the welfare and nutrition of animals. We invite all researchers interested in this type of research to join the FI through our website: www.fecobiome.com

Prevalence and Genetic Diversity of Clostridium perfringens Isolates in Hospitalized Diarrheal Patients from Central China

Objective

This study aimed to investigate the prevalence, genetic diversity and clinical characteristics of Clostridium perfringens isolates from hospitalized clinical diarrheal patients.

Methods

A prospective study was conducted on 1108 patients with diarrhea during hospitalization. Stool samples were cultured for C. perfringens, and the toxin genes were detected by PCR. The available clinical data of 112 patients were analyzed to study the clinical features of various isolates. Multi-locus sequence typing (MLST) was performed to assess phylogenetic relationship between different isolates.

Results

A total of 153 (13.8%) isolates were obtained from patients’ stools. C. perfringens type F (49.0%) was the major toxin type in the isolates, followed by type A (n = 59, 38.6%) and type C (n = 14, 9.2%). Patients older than 50 years and those with underlying diseases of cancer, hepatobiliary system, and ulcerative colitis (UC) were more predisposed to C. perfringens type F and type A infection than to type C. The patients infected with type C experienced more severe clinical symptoms compared to those with type A infection. There was a significant association between type F^C and foodborne gastrointestinal (GI) diseases (p = 0.018), between type F^P and antibiotic-associated diarrhea (AAD) (p < 0.001), and between type A and sporadic diarrhea (SD) (p < 0.001). Phylogenetic analysis indicated that type F isolates carrying a chromosomal cpe gene mainly belonged to ST77 (6/15 isolates). Type F isolates with cpe gene on a plasmid exhibited high genetic diversity.

Conclusion

High prevalence and considerable genetic diversity of C. perfringens type F were found in clinical diarrheal patients. Elderly people and patients with cancer, hepatobiliary diseases or UC, or suspected of having food poisoning (FP) may be targeted for routine testing of C. perfringens toxin genes and may benefit from early detection of C. perfringens type C isolates that cause more severe clinical symptoms.

Bacteriological and molecular typing of Clostridium perfringens strains isolated in retail beef in Beijing, China

Clostridium perfringens is an important zoonotic pathogen. This study was designed to explore the prevalence and toxin types of C. perfringens in retail beef collected from Beijing, China. Among 221 beef samples collected, 53 samples were positive for C. perfringens, resulting in the average prevalence as 23.98%. By toxin gene-based typing, the most C. perfringens strains belong to type A (96.23%, 51/53), only 2 strains were identified as type D. By a multi-locus sequence typing (MLST)-based analysis, a total of 36 sequence types (STs) were detected, and the most STs (n=30) represented just a single strain. These finding suggested that the prevalence of C. perfringens in retail beef in Beijing was considerably high and these bacteria displayed extreme diversity in genetics.

Influence of operating conditions on the persistence of E. coli, enterococci, Clostridium perfringens and Clostridioides difficile in semi-continuous mesophilic anaerobic reactors

This study examined the combined effect of hydraulic retention time (HRT), organic loading rate (OLR) and heat pretreatment of manure (70 °C, 1 h) on the fate of E. coli, enterococci, C. perfringens, C. difficile, and on chemical parameters (volatile fatty acids and ammonia) that may inactivate pathogens. Semi-continuous mesophilic anaerobic reactors were fed with pig manure and horse feed. The operating conditions were 2, 3, 4 COD.L^-1.d^-1 (OLR), 24, 35, 46 days (HRT) and use or not of a thermal pretreatment. The levels of the chemical parameters did not reach concentrations capable of inactivating the four bacteria. Anaerobic digestion led to a Log₁₀ removal > 3 (E. coli), 0.9-2.1 (enterococci), 0.1-0.6 (C. perfringens) and 0-1 (C. difficile). Increasing HRT only reduced the concentration of E. coli in the digestate. Increasing OLR reduced the Log₁₀ removal of enterococci and C. difficile. The heat pretreatment led to non-detection of E. coli in the digestate, reduced the concentration of C. perfringens by 0.8-1.3 Log₁₀ and increased the concentration of C. difficile by 0.04-0.7 Log₁₀. Enterococci, not detected in the heated manure, were present in the digestate. The distribution of genes encoding virulence factors of C. difficile (tcdA and tcdB) and C. perfringens (cpa, cpb2 and cpb) was not impacted by anaerobic digestion or by the heat pretreatment. Enterococci, C. perfringens, C. difficile were present in the digestate at relatively stable concentrations regardless of the operating conditions, indicating that even with heat pretreatment, the biosafety of digestate cannot be guaranteed in mesophilic conditions.

Tracing Clostridium perfringens strains from beef processing of slaughter house by pulsed-field gel electrophoresis, and the distribution and toxinotype of isolates in Shaanxi province, China

The purpose of this study was to investigate the distribution and specify the transmission and cross-contamination of Clostridium perfringens (C. perfringens) in the beef slaughtering and butchering process. The prevalence of 21.2% (150/708) yielded 208 isolates of C. perfringens, including 80.8% type A and 19.2% type D, 0.4% (3/708) samples carried both type A and D strains, and 72.5% type D isolates carried both cpe and atyp.cpb2 genes. C. perfringens were identified through the whole slaughtering process but no type F (cpe and cpa isolates) was found. 69 isolates were further analyzed and classified into 28 PFGE genotypes and clade I contained 94.2% isolates and 24 PFGE genotypes, which showed the genetic diversity and epidemic correlation. Our study traced C. perfringens contamination along the handling processes and showed a gradually ascending contamination rate during the whole process, revealing widespread cross-contamination from the feces and hides of slaughtered cattle to the carcass in the slaughtering workshop, so as from tools and personnel to meat of the cutting workshops. Strains from different slaughterhouses (regions) have high homology, and type A is the predominant toxinotype. It is necessary to monitor and control several key points of cross-contamination during slaughtering process to reduce a risk of C. perfringens infection.

Antimicrobial resistance profiling and molecular typing of ruminant-borne isolates of Clostridium perfringens from Xinjiang, China

OBJECTIVES

Clostridium perfringens (C. perfringens) can cause intestinal diseases in livestock and humans, which seriously threatens the healthy development of animal husbandry and human food safety. Here, the characteristics of antimicrobial resistance and molecular typing of ruminant-borne strains of C. perfringens in Xinjiang, China were explored and profiled.

METHODS

A total of 307 clinical feces collected from ruminants (cattle and sheep) with diarrheal symptoms were screened for C. perfringens. The recovered isolates were characterized in respect to their antimicrobial resistance pattern and molecular typing.

RESULTS

A total of 109 isolates of C. perfringens were isolated from 307 clinical feces of ruminants, most of which displayed the multidrug resistance (MDR) phenotype. Demonstration of the quinolone-resistance gene was the highest among the isolates (70.6%). The multiplex PCR typing based on toxin genes showed that type A and type D strains made up 82.6% (90/109) and 17.4% (19/109), among which, the isolates carrying β2 gene occupied 43.3% (39/90) of type A strains and 31.6% (6/19) of type D strains. These isolates were divided into 6 genotypes (I-VI) by enterobacterial repetitive intergenic consensus sequence-based PCR (ERIC-PCR) method. A total of 33 ST types (ST1-ST33) were identified by multilocus sequence typing (MLST) method.

CONCLUSION

C. perfringens isolates with multidrug resistance (MDR) were frequent and circulating in ruminants. Among them, type A-Ⅰ-ST19 was the dominant genotype of C. perfringens, displaying obvious genetic diversity. This study provided important epidemiological data for the risk assessment of food safety associated with ruminant-borne C. perfringens in Xinjiang, China.

Densitometric analysis of rep-PCR data: Insight into genetic variability and transmission of Clostridium perfringens typed with an improved multiplex PCR

An epidemiological study was conducted in North-East India (part of Indo-Burma biodiversity hotspot) to better understand the distribution, diversity, and transmission of Clostridium perfringens among livestock, pets, wild animals (captive), and humans. A total of 160 C. perfringens isolates were recovered from 642 diarrhoeic faecal samples with an isolation rate of 24.92%. Isolation rate was the highest among captive wild animals (37.5%) followed by dog (34.6%), human (33.8%), pig (32.7%), cattle (20.8%), goat (18.3%) and poultry (9.3%). Isolates were toxin typed using a seven gene multiplex PCR designed for simultaneous detection of cpa, cpb, cpb2, etx, iap, cpe and netB. The majority of isolates, 128 (80%) were of type A, followed by 17 (10.62%), 5 (3.12%), 4 (2.5%), 3 (1.87%), 2 (1.25%) and 1 (0.63%) isolates of type C, D, E, G, F and B, respectively. Beta 2 toxin gene was present in 65 (50%) of type A isolates, followed by 7 (41.2%), 4 (80%), 1(25%), and 1 (100%) of type C, D, G and B isolates, respectively. Beta 2 toxin has a high prevalence among dogs (28.6%), cattle (27.3%), and pig (20.8%) compared to humans, goat, wild animals, and poultry (1.2-14.3%). The prevalence of CPE and NetB toxin-positive strains was low, with only 3 (1.8%) and 5 (3.1%) isolates, respectively. Association of C. perfringens with diarrhoea in Civet Cat, Golden Langur, and Gray Langur has been reported for the first time. The genetic diversity and transmission of isolates were investigated using automated rep-PCR (Diversilab®, bioMérieux) using two densitometry-based matrices: modified Kullback-Leibler (KL) and Pearson's correlation (PC). The PC and modified KL matrices formed three distinct clusters with 59% and 27.2% similarity, respectively. C. perfringens diversity and transmission were best studied using modified KL matrix that placed more emphasis on the presence of bands rather than intensity. However, the PC method was found to be more suitable for differentiating strains within a toxin type, with slightly higher D-values.

Innovative and Highly Sensitive Detection of Clostridium perfringens Enterotoxin Based on Receptor Interaction and Monoclonal Antibodies

Clostridium perfringens enterotoxin (CPE) regularly causes food poisoning and antibiotic-associated diarrhea; therefore, reliable toxin detection is crucial. To this aim, we explored stationary and mobile strategies to detect CPE either exclusively by monoclonal antibodies (mAbs) or, alternatively, by toxin-enrichment via the cellular receptor of CPE, claudin-4, and mAb detection. Among the newly generated mAbs, we identified nine CPE-specific mAbs targeting five distinct epitopes, among them mAbs recognizing CPE bound to claudin-4 or neutralizing CPE activity in vitro. In surface plasmon resonance experiments, all mAbs and claudin-4 revealed excellent affinities towards CPE, ranging from 0.05 to 2.3 nM. Integrated into sandwich enzyme-linked immunosorbent assays (ELISAs), the most sensitive mAb/mAb and claudin-4/mAb combinations achieved similar detection limits of 0.3 pg/mL and 1.0 pg/mL, respectively, specifically detecting recombinant CPE from spiked feces and native CPE from 30 different C. perfringens culture supernatants. The implementation of mAb- and receptor-based ELISAs into a mobile detection platform enabled the fast detection of CPE, which will be helpful in clinical laboratories to diagnose diarrhea of assumed bacterial origin. In conclusion, we successfully employed an endogenous receptor and novel high affinity mAbs for highly sensitive and specific CPE-detection. These tools will be useful for both basic and applied research.

Prevalence and antimicrobial susceptibility of Clostridium perfringens in chickens and pigs from Beijing and Shanxi, China

The prevalence and antimicrobial susceptibility of Clostridium perfringens (C. perfringens) in chickens and pigs were investigated in Beijing and Shanxi, China. In total, 322 C. perfringens (chicken n = 60 and pig n = 262) were obtained from 620 feces of chickens (n = 256) and pigs (n = 364). Multiplex PCR for toxin typing of C. perfringens revealed that all the isolates belong to type A, with 45.7 % (147/322) isolates carrying beta-2 toxin-encoding gene cpb2. Minimum inhibitory concentrations of 27 antimicrobial agents showed that 91.0 % of the tested C. perfringens isolates were resistant to gentamicin and sulfonamides (sulfisoxazole and trimethoprim-sulfamethoxazole), and little resistance was showed to amoxicillin-clavulanate, ceftiofur, doxycycline, vancomycin and linezolid. Additionally, nosiheptide, avilamycin, virginiamycin and bacitracin exhibited good activity against the tested C. perfringens with low MIC50 (0.06 to ≤4 μg/mL) and MIC90 values (0.25-8 μg/mL). Whole genome sequencing (WGS) of 48 representative isolates from each farm indicated that the C. perfringens contained diverse antimicrobial resistance genes [tetA(P), ant(6)-Ib, erm(Q), etc.] and toxin genes (cpb2, colA, cloSI, pfoA, etc.). By comparative analysis, four C. perfringens isolates from three different pig farms harboured cpb2-carrying plasmid p1 with 100 % nucleotide sequence identity, suggesting horizontal gene transfer among these microorganisms. The further phylogenomic reconstruction, based on the core-genome single nucleotide polymorphisms (SNPs) of the representatives, demonstrating that C. perfringens from the same farms and regions were closely related. These findings expanded our knowledge of C. perfringens isolated from animals in China, which provided scientific basis for efficient intervention or prevention measures of antimicrobial resistance in animal husbandry in China.

Molecular Characterization of Clostridium perfringens Strains Isolated in Italy

Clostridium (C.) perfringens is the causative agent of several diseases and enteric infections in animals and humans. The pathogenicity of the bacterium is largely mediated by the production of a wide range of toxins. Individual C. perfringens strains produce only subsets of this toxin repertoire, which permits the classification in seven toxinotypes (A–G). In addition, a variety of minor toxins further characterizes the single strains. The aim of this work was to evaluate, using Polymerase Chain Reaction (PCR) assays, the diversity of 632 C. perfringens strains isolated in Italy over 15 years. The genotyped strains were analyzed to determine the presence of major and minor toxins (cpe, consensus, and atypical cpb2), their geographical origins, and the source of isolation (animal species or food). Our study shows that toxinotype A had the greatest representation (93%) and correlated mainly with consensus cpb2 in a variety of animal species, as well as with atypical cpb2 in the five food samples. Type D, associated with cpe and atypical cpb2 minor toxins, was identified in 3% of the cases, and type F was identified in 2.5%. Seven type C isolates (1.1%) were detected in cattle, whereas the only type B atypical cpb2 isolated in Italy was detected in a goat, and one type E cpe+atypical cpb2 was detected in a sheep. Type G was not detected.

Clostridium perfringens as Foodborne Pathogen in Broiler Production: Pathophysiology and Potential Strategies for Controlling Necrotic Enteritis

Clostridium perfringens (Cp.) is the cause of human foodborne desease. Meat and poultry products are identified as the main source of infection for humans. Cp. can be found in poultry litter, feces, soil, dust, and healthy birds' intestinal contents. Cp. strains are known to secrete over 20 identified toxins and enzymes that could potentially be the principal virulence factors, capable of degrading mucin, affecting enterocytes, and the small intestine epithelium, involved in necrotic enteritis (NE) pathophysiology, also leading to immunological responses, microbiota modification and anatomical changes. Different environmental and dietary factors can determine the colonization of this microorganism. It has been observed that the incidence of Cp-associated to NE in broilers has increased in countries that have stopped using antibiotic growth promoters. Since the banning of such antibiotic growth promoters, several strategies for Cp. control have been proposed, including dietary modifications, probiotics, prebiotics, synbiotics, phytogenics, organic acids, and vaccines. However, there are aspects of the pathology that still need to be clarified to establish better actions to control and prevention. This paper reviews the current knowledge about Cp. as foodborne pathogen, the pathophysiology of NE, and recent findings on potential strategies for its control.

Characterization of Clostridium Perfringens Isolates Collected from Three Agricultural Biogas Plants over a One-Year Period

Digestate produced by agricultural biogas plants (BGPs) may contain pathogenic bacteria. Among them, Clostridium perfringens deserves particular attention due to its ability to grow under anaerobic conditions and persist in amended soil. The aim of this study was to examine the potential pathogenicity and the antimicrobial resistance of C. perfringens in manure and digestate collected from three agricultural biogas plants (BGPs). A total of 157 isolates (92 from manure, 65 from digestate) were screened for genes encoding seven toxins (cpa, cpb, etx, iapcpe, netB, and cpb2). The 138 cpa positive isolates were then screened for tetA(P), tetB(P), tet(M), and erm(Q) genes and tested for antimicrobial susceptibility. The toxinotypes identified in both manure and digestate were type A (78.3% of the isolates), type G (16.7%), type C (3.6%), and type D (1.4%), whereas none of the isolates were type F. Moreover, half of the isolates carried the cpb2 gene. The overall prevalence of tetA(P) gene alone, tetA(P)-tetB(P) genes, and erm(Q) gene was 31.9, 34.8, and 6.5%, respectively. None of the isolates harbored the tet(M) gene. Multiple antimicrobial resistant isolates were found in samples that were collected from all the manure and digestates. Among them, 12.3% were highly resistant to some of the antibiotics tested, especially to clindamycin (MIC ≥ 16 µg/mL) and tilmicosin (MIC > 64 µg/mL). Some isolates were highly resistant to antibiotics used in human medicine, including vancomycin (MIC > 8 µg/mL) and imipenem (MIC > 64 µg/mL). These results suggest that digestate may be a carrier of the virulent and multidrug resistant C. perfringens.

Prevalence and multilocus sequence typing of Clostridium perfringens isolated from 4 duck farms in Shandong province, China

Clostridium perfringens is an important zoonotic microorganism. The present study was undertaken to investigate prevalence, serotype distribution, antibiotic resistance, and genetic diversity of C. perfringens isolates from 4 duck farms in Shandong, China. In total, 424 samples of cloacal swabs and environment were collected from 3 commercial meat-type duck farms in Tai'an, Liaocheng, and Weifang and one breeder duck farm in Liaocheng between December 2018 and June 2019, of which, 207 (48.82%) samples were determined to be positive for C. perfringens; a total of 402 isolates of C. perfringens were recovered, all of which were identified as type A; 30.85% of the isolates were positive for cpb2 gene; and cpe gene was found in 0.5% of the isolates. Antimicrobial susceptibility testing revealed that some of the isolates exhibited high antibiotic resistance, and 39.14% of the isolates were resistant to at least 5 classes of commonly used antibiotics. Multilocus sequence typing analysis showed that 85 representative isolates encompassed 54 different sequences types (STs), clustered in 5 clonal complexes (CCs) and 40 singletons. ST3, the most common ST in 54 STs, constituting 15.29% of all isolates, was also the most prevalent ST of isolates from the Liaocheng breeder duck farm (farm 3). CC1, the most prolific CC, containing 15.29% of the analyzed isolates, was the popular subtype of isolates from Liaocheng meat duck farm (farm 2). Although all the isolates belong to type A, the genetic diversity varied greatly in different regions; the Simpson's Diversity Index of STs for Liaocheng, Tai'an, and Weifang were 0.5941, 0.9198, and 0.9627, respectively. Some of cloacal isolates and environmental isolates were distributed in the same ST or CC, indicating close genetic relationship between cloacal isolates and environmental isolates. A portion of the strains from humans and ducks was found to be phylogenetically close. The close relationship between strains from humans and ducks, the high antibiotic resistance of C. perfringens, and the cpe-positive isolates indicated potential public health risks.

Multilocus sequence typing of Clostridium perfringens strains from neonatal calves, dairy workers and associated environment in India

Clostridium perfringens is a globally recognized zoonotic pathogen. We report isolation and genotyping of C. perfringens from neonatal calves, dairy workers and their associated environment in India. A total of 103 fecal samples from neonatal calves, 25 stool swabs from the dairy workers and 50 samples from their associated environment were collected from two dairy farms. C. perfringens was detected in 26 out of 103 (25.2%) neonatal calf samples, 7 out of 25 (28%) human stool samples and 17 out of 50 (34%) environmental samples. C. perfringens type A strains were predominant in neonatal calves (24/26; 92.3%) and associated environment (15/17; 88.2%). In contrast, strains from dairy workers mostly belonged to type F (5/7; 71.4%), which also carried the beta2 toxin gene. Seventeen strains were analyzed by multilocus sequence typing (MLST) for studying genotypic relationship along with 188 C. perfringens strains available from public databases. A total of 112 sequence types (STs) were identified from 205 C. perfringens strains analyzed. A Clonal complex (CC) represented by three STs (ST 98, ST 41 and ST 110) representing predominantly type F (18/20 strains) were mostly associated with human illnesses. Among predominant STs, ST 54 was associated with enteritis cases in foals and dogs and ST 58 associated with necrotic enteritis in poultry. Seventeen Indian strains were assigned to 13 STs. Genetic relatedness among strains of calves, dairy worker and associated environments indicate inter-host transfers and zoonotic spreads.

Large-Scale Genomic Analyses and Toxinotyping of Clostridium perfringens Implicated in Foodborne Outbreaks in France

Clostridium perfringens is both an ubiquitous environmental bacterium and the fourth most common causative agent of foodborne outbreaks (FBOs) in France and Europe. These outbreaks are known to be caused by C. perfringens enterotoxin (CPE) encoded by the cpe gene. However, additional information on the toxin/virulence gene content of C. perfringens has become available in the last few years. Therefore, to understand the enteropathogenicity of this bacterium, we need to describe the toxin and virulence genes content of strains involved in FBOs. In this study, we used a new real-time PCR typing technique based on a comprehensive set of 17 genes encoding virulence factors. The analysis was performed on a collection of 141 strains involved in 42 FBOs in the Paris region. It was combined with whole genome sequence (WGS) phylogenomic reconstruction, based on the coregenome single nucleotide polymorphisms (SNPs) of 58 isolates, representatives of the identified virulence gene profiles. Two or three different virulence gene profiles were detected in 10 FBOs, demonstrating that C. perfringens FBOs may be associated with heterogeneous strains. cpe-positive strains were isolated in 23 outbreaks, confirming the prominent role of CPE in pathogenicity. However, while C. perfringens was the sole pathogen isolated from the incriminated food, the cpe gene was not detected in strains related to 13 outbreaks. This result indicates either that the standard method was not able to isolate cpe+ strains or that the cpe gene may not be the only determinant of the enterotoxigenic potential of C. perfringens strains. Using phylogenomic reconstruction, we identified two clades distinguishing chromosomal cpe-positive from cpe-negative and plasmid-borne cpe. Important epidemiological information was also garnered from this phylogenomic reconstruction that revealed unexpected links between different outbreaks associated with closely related strains (seven SNP differences) and having common virulence gene profiles. This study provides new insight into the characterization of foodborne C. perfringens and highlights the potential of WGS for the investigation of FBOs.

Identification of epsilon toxin-producing Clostridium perfringens strains in American retail food

Food samples (n = 216) from New York city were tested for the presence of C. perfringens via PCR for specific toxin genes. Thirty-four (16%) samples were positive for C. perfringens. Of these 34, 31 (91.2%) were type A or E, one (2.9%) was type B, and two (5.9%) were type D.

The application of rumen simulation technique (RUSITEC) for studying dynamics of the bacterial community and metabolome in rumen fluid and the effects of a challenge with Clostridium perfringens

The rumen simulation technique (RUSITEC) is a well-established semicontinuous in vitro model for investigating ruminal fermentation; however, information on the stability of the ruminal bacterial microbiota and metabolome in the RUSITEC system is rarely available. The availability of high resolution methods, such as high-throughput sequencing and metabolomics improve our knowledge about the rumen microbial ecosystem and its fermentation processes. Thus, we used Illumina MiSeq 16S rRNA amplicon sequencing and a combination of direct injection mass spectrometry with a reverse-phase LC-MS/MS to evaluate the dynamics of the bacterial community and the concentration of several metabolites in a RUSITEC experiment as a function of time and in response to a challenge with a pathogenic Clostridium perfringens (C. perfringens) strain. After four days of equilibration, samples were collected on days 5, 6, 7, 10, 12 and 15 of the steady-state and experimental period. From a total of six fermenters, three non-infected fermenters were used for investigating time-dependent alterations; three fermenters were incubated with C. perfringens and compared with the non-infected vessels at days 10, 12 and 15. Along the time-line, there was no statistically significant change of the overall bacterial community, however, some phylotypes were enriched at certain time points. A decrease in Fibrobacter and Elusimicrobia over time was followed by an increase in Firmicutes and Actinobacteria. In contrast, classical fermentation measurements such as pH, redox potential, NH3-N, short chain fatty acids and the concentrations of metabolites determined by metabolomics (biogenic amines, hexoses and amino acids) remained stable throughout the experiment. In response to C. perfringens addition the concentrations of several amino acids increased. Although the overall bacterial community was not altered here either, some minor changes such as an enrichment of Synergistetes and Bacteroidetes were detectable over time. In conclusion, both, the bacterial community composition and the metabolome in the RUSITEC system were relatively stable during the experiment.