Amount of enterotoxigenic Clostridium perfringens in meat detected by nested PCR

Addressing Current Challenges in Poultry Meat Safety: Development of a Cultivation and Colony Hybridization Approach to Recover Enterotoxigenic Clostridium perfringens from Broiler Chicken Carcasses

Enterotoxigenic Clostridium perfringens is one of the main causes of foodborne illness in Canada. The use of a conventional bacterial culture approach to isolate enterotoxigenic C. perfringens from poultry meat is common. This approach is based on the phenotype attributable to a double hemolysis phenomenon, whereas few enterotoxigenic strains of C. perfringens produce it, which further complicates the study of the reservoirs of this important pathogen. The objectives of the current study were to validate the ability of a digoxigenin-labeled probe to detect the C. perfringens cpe gene and to validate the use of either a filtration or a direct plating approach, combined with colony hybridization to detect enterotoxigenic C. perfringens. Pure DNA and pure colonies of enterotoxigenic C. perfringens and broiler chicken carcass rinsate samples were subjected to colony hybridization. The results showed that the synthesized DNA probe can detect the cpe gene from both DNA and pure colonies of enterotoxigenic C. perfringens, and from colonies grown from carcass rinsates artificially contaminated with enterotoxigenic C. perfringens. Our study suggests that this isolation method is a promising tool for a better understanding of the epidemiology of this zoonotic pathogen.

Clostridium perfringens Associated with Foodborne Infections of Animal Origins: Insights into Prevalence, Antimicrobial Resistance, Toxin Genes Profiles, and Toxinotypes

Several food-poisoning outbreaks have been attributed to Clostridium perfringens (C. perfringens) worldwide. Despite that, this crisis was discussed in a few studies, and additional studies are urgently needed in this field. Therefore, we sought to highlight the prevalence, antimicrobial resistance, toxin profiles, and toxinotypes of C. perfringens isolates. In this study, 50 C. perfringens isolates obtained from 450 different animal origin samples (beef, chicken meat, and raw milk) were identified by phenotypic and genotypic methods. The antimicrobial susceptibility results were surprising, as most of the isolates (74%) showed multidrug-resistant (MDR) patterns. The phenotypic resistance to tetracycline, lincomycin, enrofloxacin, cefoxitin/ampicillin, and erythromycin was confirmed by the PCR detections of tet, lnu, qnr, bla, and erm(B) genes, respectively. In contrast to the toxinotypes C and E, toxinotype A prevailed (54%) among our isolates. Additionally, we found that the genes for C. perfringens enterotoxin (cpe) and C. perfringens beta2 toxin (cpb2) were distributed among the tested isolates with high prevalence rates (70 and 64%, respectively). Our findings confirmed that the C. perfringens foodborne crisis has been worsened by the evolution of MDR strains, which became the prominent phenotypes. Furthermore, we were not able to obtain a fixed association between the toxinotypes and antimicrobial resistance patterns.

The Circulation of Type F Clostridium perfringens among Humans, Sewage, and Ruditapes philippinarum (Asari Clams)

Clostridium perfringens is an important pathogen that is responsible for gastroenteritis; the causative agent for the symptoms is C. perfringens enterotoxin (CPE), which is mainly produced by type F C. perfringens. Since shellfishes may gather C. perfringens in the water environment, this study estimated the potential circulation of type F C. perfringens among humans, sewage, and Ruditapes philippinarum (asari clams) as a result of sewage pollution. A comparison of the characteristics among the isolates from 86 sewage influents, 36 effluents, 76 asari clams, and 37 humans was conducted. Serotyping, cpe genotyping, and toxin genotyping showed that C. perfringens with a plasmid IS1151 sequence downstream of cpe was predominant among sewage influents, effluents, humans, and asari clams. Multilocus sequence typing suggested that some isolates from a human, sewage influents, effluents, and asari clams were linked to each other. These results demonstrated that asari clams are the necessary infection sources of C. perfringens responsible for carriers and foodborne diseases, and that these pathogens from humans infected by asari clams can pollute the water environment. It is useful to assess bacteria such as C. perfringens isolates from sewage to estimate the trend of those from the community.

Broiler chicken carcasses and their associated abattoirs as a source of enterotoxigenic Clostridium perfringens: Prevalence and critical steps for contamination

Clostridium perfringens ranks among the three most frequent bacterial pathogens causing human foodborne diseases in Canada, and poultry meat products are identified as a source of infection for humans. The objective of the current study was to estimate the proportion of broiler chicken flocks, carcasses and various environmental samples from critical locations of the slaughter plant positive for the presence of C. perfringens enterotoxin encoding gene (cpe). From the 16 visits conducted, 25% of the 79 flocks sampled, 10% of the 379 carcasses sampled and 5% of the 217 environmental samples collected were found positive for cpe. The proportion of cpe-positive carcasses was statistically different between surveyed plants, with 17.0% for one abattoir and 2.2% for the other. For the most contaminated plant, cpe-positive carcasses were identified at each step of the processing line, with prevalence varying between 10.0% and 25.0%, whereas this prevalence varied between 0% and 25.0% for the environmental surfaces sampled. Based on the results obtained, enterotoxigenic C. perfringens strains could potentially represent a risk for the consumer.

Clostridium perfringens Contamination in Retail Meat and Meat-Based Products in Bursa, Turkey

This study examined the incidence of Clostridium perfringens in raw, ready-to-cook (RTC), and ready-to-eat (RTE) meat and meat-based products (N = 306) collected from restaurants, supermarkets, and butcher shops in Bursa, Turkey. In addition, we investigated the presence of the C. perfringens enterotoxin (CPE), as well as cpe genes and their source (chromosomal or plasmid borne). In this study, tryptose sulfite cycloserine (TSC) agar for classic culture isolation and API and real-time polymerase chain reaction (RT-PCR) techniques were used to identify C. perfringens and detect cpa and cpe genes from these products, respectively. Seventeen C. perfringens isolates (5.6%) were isolated and identified with API 20A. In addition, 42 of 81 suspicious isolates (51.9%) were identified as C. perfringens using RT-PCR. Of the 81 suspicious isolates tested by RT-PCR, 22 (27.2%) carried the cpe gene either on the plasmid or chromosome. Twenty-one isolates were positive for chromosomal cpe (C-cpe), and one was positive for plasmid-borne cpe (P-cpe). CPE was detected in 31.8% (7/22) of the cpe positive isolates by the PET-RPLA test. In conclusion, C. perfringens and their CPEs were present in raw, RTC, and RTE meat and meat-based foods in this study. It is emphasized that the presence of C. perfringens and the cpe gene in these foods may be a potential risk for human health.

Toxinotyping and Antimicrobial Resistance of Clostridium Perfringens Isolated from Processed Chicken Meat Products

Introduction

The toxinotyping and antimicrobial susceptibility of Clostridium perfringens strains isolated from processed chicken meat were determined.

Material and Methods

Two hundred processed chicken meat samples from luncheon meats, nuggets, burgers, and sausages were screened for Clostridium perfringens by multiplex PCR assay for the presence of alpha (cpa), beta (cpb), epsilon (etx), iota (ia), and enterotoxin toxin (cpe) genes. The C. perfringens isolates were examined in vitro against eight antibiotics (streptomycin, amoxicillin, ampicillin, ciprofloxacin, lincomycin, cefotaxime, rifampicin, and trimethoprim-sulfamethoxazole)

Results

An overall of 32 C. perfringens strains (16%) were isolated from 200 processed chicken meat samples tested. The prevalence of C. perfringens was significantly dependent on the type of toxin genes detected (P = 0.0), being the highest in sausages (32%), followed by luncheon meats (24%), burgers (6%), and nuggets (2%). C. perfringens type A was the most frequently present toxinotype (24/32; 75%), followed by type D (21.9 %) and type E (3.1%). Of the 32 C. perfringens strains tested, only 9 (28%) were enterotoxin gene carriers, with most representing type A (n = 6). C. perfringens strains differed in their resistance/susceptibility to commonly used antibiotics. Most of the strains tested were sensitive to ampicillin (97%) and amoxicillin (94%), with 100% of the strains being resistant to streptomycin and lincomycin. It is noteworthy that the nine isolates with enterotoxigenic potential had a higher resistance than the non-enterotoxigenic ones.

Conclusion

The considerably high C. perfringens isolation rates from processed chicken meat samples and resistance to some of the commonly used antibiotics indicate a potential public health risk. Recent information about the isolation of enterotoxigenic C. perfringens type E from chicken sausage has been reported.

Toxinotyping and antimicrobial susceptibility of enterotoxigenic Clostridium perfringens isolates from mutton, beef and chicken meat

A total of 300 meat samples comprising mutton, beef, and chicken meat (n = 100) collected from either local butcher shops or large meat outlets situated at various areas of Lahore City located in Punjab province of Pakistan were tested for the isolation of Clostridium perfringens. Prevalence of the organism was highest in the chicken (6 %) followed by mutton (5 %) and beef (1 %). Contamination level was high (10/150) in the samples collected from local butcher shops in comparison to the samples collected from large meat outlets (2/150). All of the raw meat samples were negative for the presence of alpha, beta and epsilon toxins of C. perfringens as detected through ELISA. Out of a total number of 12 isolates only half were capable of producing enterotoxins when cultured in trypticase glucose yeast (TGY) broth. Toxinotyping of the isolates showed that 3 were of type A while one each of the remaining three belonged to type B, C, and D. Antibiotic susceptibility testing of the toxin producing isolates revealed that C. perfringens were susceptible to chloramphenicol, ciprofloxacin, metronidazole, and ceftriaxone. All of the other drugs were relatively less effective with a least activity of amoxicillin against the isolates.

Evaluation of a multiplex PCR assay for simultaneous detection of bacterial and viral enteropathogens in stool samples of paediatric patients

We evaluated a multiplex PCR assay, the Seeplex Diarrhoea ACE detection, that simultaneously detects 15 enteric pathogens, including Salmonella spp., Shigella spp., Vibrio spp., toxin B producer Clostridium difficile, Campylobacter spp., Clostridium perfringens, Yersinia enterocolitica, Aeromonas spp., Escherichia coli O157:H7, verocytotoxin-producing Escherichia coli, adenovirus, Group A rotavirus, norovirus GI and GII, and astrovirus. We compared this assay with clinical methods routinely used in our laboratory, for detecting enteropathogens in stool samples collected from 245 paediatric patients with suspected infectious gastroenteritis. We recovered 61 bacterial pathogens and 121 enteric viruses with our laboratory assays, while we detected 78 bacteria and 167 viruses with the molecular assay. We calculated specificity and sensitivity for both methods after analysis of discordant results and demonstrated greater sensitivity for multiplex PCR than for our routine methods, with the exception of Salmonella spp. and toxigenic C. difficile detection. The multiplex PCR assay proved to be a reliable tool to directly detect the most common enteropathogens in stool samples but with some limitations.

Presence of Clostridium perfringens in retail chicken livers

Chicken livers sold at grocery stores in Tucson, AZ, USA were examined for the presence of Clostridium perfringens. Results showed that 69.6% of sampled retail chicken livers were culture positive for C. perfringens. Genotyping of the isolates showed that all the isolates were type A, but were negative for the enterotoxin gene (cpe).

Enterotoxigenic Clostridium perfringens: detection and identification

Recent advances in understanding the genetics of enterotoxigenic Clostridium perfringens, including whole genome sequencing of a chromosomal cpe strain and sequencing of several cpe-carrying large plasmids, have led to the development of molecular approaches to more precisely investigate isolates involved in human gastrointestinal diseases and isolates present in the environment. Sequence-based PCR genotyping of the cpe locus (cpe genotyping PCR assays) has provided new information about cpe-positive type A C. perfringens including: 1) Foodborne C. perfringens outbreaks can be caused not only by chromosomal cpe type A strains with extremely heat-resistant spores, but also less commonly by less heat-resistant spore-forming plasmid cpe type A strains; 2) Both chromosomal cpe and plasmid cpe C. perfringens type A strains can be found in retail foods, healthy human feces and the environment, such as in sewage; 3) Most environmental cpe-positive C. perfringens type A strains carry their cpe gene on plasmids. Moreover, recent studies indicated that the cpe loci of type C, D, and E strains differ from the cpe loci of type A strains and from the cpe loci of each other, indicating that the cpe loci of C. perfringens have remarkable diversity. Multi-locus sequence typing (MLST) indicated that the chromosomal cpe strains responsible for most food poisoning cases have distinct genetic characteristics that provide unique biological properties, such as the formation of highly heat-resistant spores. These and future advances should help elucidate the epidemiology of enterotoxigenic C. perfringens and also contribute to the prevention of C. perfringens food poisoning outbreaks and other CPE-associated human diseases.

Novel insights into the epidemiology of Clostridium perfringens type A food poisoning

Clostridium perfringens food poisoning ranks among the most common gastrointestinal diseases in developed countries. The disease is caused by C. perfringens enterotoxin (CPE) encoded by cpe and produced by less than 5% of C. perfringens type A strains. Molecular epidemiological research in the past 15 years has focused on the reservoirs and routes of cpe-positive C. perfringens aiming to clarify the role and epidemiology of chromosomal and plasmid-borne cpe-carrying strains. This literature review highlights novel aspects in the epidemiology of CPE-mediated diseases. We suggest that (1) chromosomal and plasmid-borne cpe-carrying C. perfringens strains are genetically and epidemiologically distinct and have adapted to different environments; (2) not only chromosomal but also plasmid-borne cpe-carrying C. perfringens strains cause food poisonings; (3) other CPE-mediated diseases, such as antibiotic-associated and sporadic diarrhea, associated with plasmid-borne cpe-positive strains, may be food-related; (4) the role of animals as the main reservoir of cpe-positive C. perfringens needs to be reconsidered; (5) humans serve as an important reservoir of cpe-positive C. perfringens, introducing a contamination risk into foods through handling; and (6) the current standard procedures to diagnose C. perfringens food poisoning fail to detect and isolate many C. perfringens strains, distorting the epidemiological understanding of C. perfringens food poisoning.

Prevalence and characterization of enterotoxin gene-carrying Clostridium perfringens isolates from retail meat products in Japan

Clostridium perfringens is an important anaerobic pathogen causing food-borne gastrointestinal (GI) diseases in humans and animals. It is thought that C. perfringens food poisoning isolates typically carry the enterotoxin gene (cpe) on their chromosome, while isolates from other GI diseases, such as antibiotic-associated diarrhea, carry cpe on a transferable plasmid. However, food-borne GI disease outbreaks associated with C. perfringens isolates carrying plasmid-borne cpe (plasmid cpe isolates) were recently reported in Japan and Europe. To investigate whether retail food can be a reservoir for food poisoning generally, we evaluated Japanese retail meat products for the presence of two genotypes of enterotoxigenic C. perfringens. Our results demonstrated that approximately 70% of the Japanese retail raw meat samples tested were contaminated with low numbers of C. perfringens bacteria and 4% were contaminated with cpe-positive C. perfringens. Most of the cpe-positive C. perfringens isolates obtained from Japanese retail meat carried cpe on a plasmid. The plasmid cpe isolates exhibited lower spore heat resistance than did chromosomal cpe isolates. Collectively, these plasmid cpe isolates might be causative agents of food poisoning when foods are contaminated with these isolates from equipment and/or the environment after cooking, or they may survive in food that has not been cooked at a high enough temperature.

Clostridium perfringensand its toxins in minced meat from Kars, Turkey

The aim of this study was to determine the prevalence of Clostridium perfringens and its toxins in minced meat. A total of 96 minced meat samples were collected from local markets (16) and small butcher's shops (80) in Kars (Turkey). Samples were analysed for the presence of C. perfringens and its toxins using a commercially available ELISA kit. A total of 31 (32%) Clostridium spp. strains were isolated and 17 (55%) of these isolates were identified as C. perfringens. Four (25%) of the samples from local markets and 27 (34%) from small butcher's shops were contaminated with Clostridium spp. Furthermore, C. perfringens was isolated from two (12%) and 15 (19%) samples from local markets and small butcher's shops, respectively. Mean counts of Clostridium spp. were 2.2 +/- 0.83 x 10(2) CFU g(-1) for local markets and 4.35 +/- 8.53 x 10(2) CFU g(-1) for small butcher's shops; mean counts for C. porringers were 2.75 +/- 0.21 x 10(2) and 6.82 +/- 10.96 x 10(2) CFU g(-1) from markets and butcher's shops, respectively. The number of samples contaminated with both Clostridium spp. and C. perfringens was higher in small butcher's shops than in local markets. Moreover, higher numbers of Clostridium spp. and C. perfringens were isolated in samples from small butcher's shops than from local markets. A total of 13 (13%) samples were also positive for toxins produced by the organism, as detected by ELISA. Eleven samples from small butcher's shops and two samples from local markets were positive for the C. perfringens toxins tested. Moreover, two (12%), one (1%), four (4%) and two (2%) samples were contaminated with C. perfringens types A, B, C and D, respectively. In conclusion, some meat samples collected from local markets and small butcher's shops contained C. perfringens and its toxins and, therefore, present a potential risk of food poisoning.

Polymerase chain reaction detection of Clostridium perfringens in feces from captive and wild chimpanzees, Pan troglodytes

BACKGROUND

For veterinary management of non-human primates in captivity, and conservation of wild-living primates, management of their health risks is necessary. Incidences of pathogenic bacteria in the fecal specimens are considered as one of the useful indicators for non-invasive health monitoring.

METHODS

We carried out the detection of Clostridium perfringens in feces from captive and wild chimpanzees by the rapid polymerase chain reaction method.

RESULTS

The bacterium was detected in most fecal specimens (80%) in captive chimpanzees. Contrarily, the detection rate in the wild chimpanzees was low, with 23% (n = 12) of 53 fecal samples from the Bossou group, Guinea, and 1.2% (1/81) in the Mahale group, Tanzania.

CONCLUSIONS

These results show that the intestinal microflora differs between Pan populations under various living conditions, being influenced by their diet and environment.

Molecular subtyping of poultry-associated type A Clostridium perfringens isolates by repetitive-element PCR

Clostridium perfringens strains (type A) isolated from an integrated poultry operation were subtyped using repetitive-element PCR with Dt primers. Isolates were obtained from fecal, egg shell, fluff, and carcass rinse samples as part of a previously reported temporally linked epidemiological survey. A total of 48 isolates of C. perfringens were obtained from different stages of the broiler chicken production chain from two separate breeder farms that supplied a single hatchery that in turn provided chicks to a single grow-out farm whose flocks were processed at a single plant. All 48 isolates were typeable (100% typeability) by repetitive-element PCR with Dt primers. This subtyping method was highly reproducible and discriminatory. By repetitive-element PCR with Dt primers, isolates were classified into four major branches with 12 subgroups or clades. The Simpson's index of discrimination was calculated to be 0.96 for groupings of >95% correlation. Toxin gene profiles of the isolates indicated that all of the isolates were C. perfringens alpha-toxin gene positive and 46 of 48 isolates were beta2-toxin gene positive. All strains were negative for beta- and epsilon-toxin genes. Repetitive sequence-based PCR was found to be a technically practical and reproducible means of subtyping C. perfringens libraries from specific epidemiological or production environment settings.

Clostridium perfringens in poultry: an emerging threat for animal and public health

The incidence of Clostridium perfringens-associated necrotic enteritis in poultry has increased in countries that stopped using antibiotic growth promoters. Necrotic enteritis and the subclinical form of C. perfringens infection in poultry are caused by C. perfringens type A, producing the alpha toxin, and to a lesser extent type C, producing both alpha toxin and beta toxin. Some strains of C. perfringens type A produce an enterotoxin at the moment of sporulation and are responsible for foodborne disease in humans. The mechanisms of colonization of the avian small intestinal tract and the factors involved in toxin production are largely unknown. It is generally accepted, however, that predisposing factors are required for these bacteria to colonize and cause disease in poultry. The best known predisposing factor is mucosal damage, caused by coccidiosis. Diets with high levels of indigestible, water-soluble non-starch polysaccharides, known to increase the viscosity of the intestinal contents, also predispose to necrotic enteritis. Standardized models are being developed for the reproduction of colonization of poultry by C. perfringens and the C. perfringens-associated necrotic enteritis. One such model is a combined infection with Eimeria species and C. perfringens. Few tools and strategies are available for prevention and control of C. perfringens in poultry. Vaccination against the pathogen and the use of probiotic and prebiotic products has been suggested, but are not available for practical use in the field at the present time. The most cost-effective control will probably be achieved by balancing the composition of the feed.

Enterotoxigenicity and genetic relatedness of Clostridium perfringens isolates from retail foods in the United States

Clostridium perfringens is a leading cause of bacterial food-borne illness in countries where consumption of meat and poultry is high. For example, each year in the United States, this organism is the second or third most common cause of confirmed cases of food-borne illness. Surveys of the incidence of this organism in retail foods were done in the 1960s without regard to whether isolates were enterotoxigenic. It is now known that not all strains of this organism possess the enterotoxin gene responsible for illness. We examined the incidence of this organism in 131 food samples from retail food stores in an area of the northeastern United States. Forty isolates were obtained by using the iron milk method at 45 degrees C, with confirmation by use of motility nitrate and lactose gelatin media. The presence of the C. perfringens enterotoxin (cpe) and alpha toxin (cpa) genes was determined by PCR using previously published primer sequences. All isolates possessed cpa. None of the isolates were identified as carrying the cpe gene by this method or by another method using a digoxigenin-labeled gene probe. Consistent with these results, none of the sporulating-cell extracts contained enterotoxin as determined by reverse passive latex hemagglutination. Pulsed-field gel electrophoresis was used to determine the genetic relatedness of the isolates. About 5% of the isolates were considered to be closely related (2- to 3-band difference). The others were considered to be unrelated to one another. The results demonstrate the rarity of cpe(+) strains in retail foods and the genetic diversity among nonoutbreak strains.

Bacteriological investigation of an outbreak of Clostridium perfringens food poisoning caused by Japanese food without animal protein

An outbreak of Clostridium perfringens food poisoning occurred in a senior citizen's home in Japan. Japanese food, spinach boiled with fried bean curd, was considered to be the causative food as a result of the detection of the C. perfringens enterotoxin gene by nested PCR. The number of enterotoxin-positive C. perfringens was enumerated as 4.3 x 10(5)/g in the causative food by the MPN method combined with nested PCR. By cultivation, enterotoxin-positive C. perfringens was isolated from all the fecal specimens of patients tested and the causative food. The isolates from patients were serotypable, heat-resistant and the majority produced enterotoxin, however most isolates from the causative food were nonserotypable, enterotoxin-negative and heat-sensitive.