Production and purification of Clostridium perfringens type C beta-toxin and IgG and IgY antitoxins.

OBJECTIVES: This study aimed to produce and purify Clostridium perfringens type C beta-toxin, sheep anti-beta toxin immunoglobulin G (IgG) and chicken immunoglobulin Y (IgY). METHODS: Two methods were used for beta-toxin purification: single-step metal affinity chromatography (MAC) using zinc as a chelator and ion exchange chromatography (IEX). The purified and inactivated beta-toxoids were then administered to sheep and chickens in order to produce IgG and IgY. RESULTS: All assays using the IEX failed. In contrast, MAC purified more than 21 mg of toxin per run in a single-step protocol. The purified and inactivated beta-toxoids were then administered to sheep and chickens, and IgG and IgY were purified with a high yield, medium antibody titer of 50 IU/mL, and high avidity (73.2 %). CONCLUSIONS: C. perfringens type C beta-toxin and sheep or chicken anti-beta toxin IgG and IgY antibodies were successfully produced and purified using a simple protocol. This protocol can be used for the production of components used in the diagnosis and research of necrotic enteritis caused by C. perfringens type C, as well as for the evaluation of existing vaccines and the development of new preventive methods against this disease.

Characterization of the virulence of three novel clade 2 Clostridioides (Clostridium) difficile strains and a two-year screening in animals and humans in Brazil.

Clostridioides (Clostridium) difficile infection (CDI) is an evolving global healthcare problem, and owing to the diverse and dynamic molecular epidemiology of C. difficile, new strains continue to emerge. In Brazil, only two cases of CDI due to the so called hypervirulent PCR ribotype (RT) 027 belonging to clade 2 have ever been reported, whereas incidence of CDI due to another "hypervirulent" RT078 (clade 5) has not yet been reported. In contrast, novel clade 2 strains have been identified in different hospitals. To better understand the epidemiology of CDIs in Brazil, this study aimed to genotypically and phenotypically characterize three novel Brazilian clade 2 strains (RT883, 884, and 885) isolated from patients with confirmed CDI. In addition, to better understand the circulating RTs, a two-year sampling was conducted in patients from the same hospital and in several domestic and wild animal species. The three strains examined showed lower production of A/B toxins than the control RT027, although two of these strains harbored a truncated tcdC gene. All strains showed swimming motility similar to that of RT027, while RT883 showed higher spore production than the reference strain. In the in vivo hamster model, the lethality of all strains was found to be similar to that of RT027. Both cgMLST and cgMLSA analyses revealed a high genetic similarity among the three-novel clade 2 isolates. In the two-year survey in animals and humans, RT883, 884, and 885 were not detected; however, three new RTs (RT988, RT989, and RT990) were isolated, two of which were genetically related to the three previously reported clade 2 strains. RT106 and RT126 were most frequently detected in humans (47.9%) and animals (57.9%), respectively. Furthermore, RT027 and RT078 were not detected in humans. The results of this study suggest that these novel clade 2 strains have virulence potential and that new strains from clade 2 continue to emerge in our setting, indicating the need for long-term local surveillance.

Occurrence and characterization of methicillin-resistant Staphylococcus spp. in diseased dogs in Brazil.

Staphylococcus pseudintermedius is a major commensal bacterium of the skin and mucosae of dogs and an opportunistic agent responsible for several clinical infections, such as pyoderma, otitis, and surgical wound infections. The emergence of methicillin-resistant S. pseudintermedius (MRSP) has become a problem of great concern in veterinary and human medicine because it is multidrug resistant (MDR) and can also infect humans. This study aimed to identify the occurrence of Staphylococcus spp. in infected patients and investigate the antimicrobial resistance profiles and molecular structure of MRSP isolates. Samples were obtained from two different veterinary clinics; suggestive colonies were submitted to matrix-assisted laser desorption ionization-time of flight (MALDI-ToF) mass spectrometry and confirmed at the species level by polymerase chain reaction (PCR). Sequencing of the 16S rRNA and rpoB genes were used in selected samples that were not identified by MALDI-ToF and by the species-specific PCR. Antimicrobial susceptibility and PCR detection of mecA were performed. MRSP isolates were subjected to multilocus sequence typing. Of all the clinical staphylococci (n = 131), 98 (74.8%) were identified as S. pseudintermedius. Multidrug resistance (resistance to ≥3 classes of antimicrobials) was observed in 63.2% of S. pseudintermedius isolates, and 24.5% of S. pseudintermedius isolates were methicillin-resistant. Half of the MRSP isolates were isolated from surgical site infections. Among the ten sequence types (ST) identified, nine were novel. ST71 was the most prevalent and associated with resistance to fluoroquinolones. Prior antimicrobial therapy, hospitalization, and surgical site infections seemed to be risk factors for MRSP acquisition. The present study showed a high rate of MDR staphylococci in infected dogs. MRSP was isolated from different clinical conditions, mainly surgical site infections. Additionally, this is the first study to extensively investigate the population structure of MRSP in Brazil, which revealed the dispersion of CC71 and nine novel ST. These findings raise concerns for both animal and human health due to the zoonotic potential of this species and limited therapeutic options available for MRSP infections.

Fecal Shedding of Multidrug Resistant Escherichia coli Isolates in Dogs Fed with Raw Meat-Based Diets in Brazil.

The practice of feeding dogs raw meat-based diets (RMBDs) is growing in several countries, and the risks associated with the ingestion of pathogenic and antimicrobial-resistant Escherichia coli in dogs fed these diets are largely unknown. We characterized E. coli strains isolated from dogs fed either an RMBD or a conventional dry feed, according to the phylogroup, virulence genes, and antimicrobial susceptibility profiles of the bacteria. Two hundred and sixteen E. coli strains were isolated. Dogs fed RMBDs shed E. coli strains from the phylogroup E more frequently and were positive for the E. coli heat-stable enterotoxin 1-encoding gene. Isolates from RMBD-fed dogs were also frequently positive for multidrug-resistant E. coli isolates including extended-spectrum beta-lactamase (ESBL) producers. Whole-genome sequencing of seven ESBL-producing E. coli strains revealed that they predominantly harbored blaCTX-M-55, and two strains were also positive for the colistin-resistant gene mcr-1. These results suggest that feeding an RMBD can affect the dog's microbiota, change the frequency of certain phylogroups, and increase the shedding of diarrheagenic E. coli. Also, feeding an RMBD seemed to be linked with the fecal shedding of multidrug-resistant E. coli, including the spread of strains harboring mobilizable colistin resistance and ESBL genes. This finding is of concern for both animal and human health.

Laboratory diagnosis of Clostridioides (Clostridium) difficile infection in domestic animals: A short review.

Despite the known importance of Clostridioides (Clostridium) difficile infection (CDI) in animals, there are no published guidelines for the diagnosis of CDI. The performance of the available commercial methods, all standardized for human stool samples, can vary according to the animal species. Thus, the aim of the present study was to review the literature on the detection of C. difficile in pigs, horses, and dogs. The detection of toxins A and B using enzyme immunoassays seems to have low performance in piglet and dog samples, while it shows high sensitivity for the diagnosis of CDI in foals. On the other hand, tests for the detection of glutamate dehydrogenase (GDH) have a high sensitivity towards detection of C. difficile in animal samples, suggesting that it can be an adequate screening method. A few studies have evaluated real-time PCR or nucleic acid amplification tests in animal samples and, so far, these methods have also shown a low performance for the detection of C. difficile in animals. Although the intestinal lesions caused by CDI can vary among animal species, histopathology can be a useful auxiliary tool for postmortem diagnosis in animals.

Clostridioides difficile and multi-drug-resistant staphylococci in free-living rodents and marsupials in parks of Belo Horizonte, Brazil.

The global emergence of antimicrobial resistance (AMR) has become a serious threat to human and animal health. Recent studies have shown that synanthropic animals can act as reservoirs and disseminators of pathogens and resistant bacteria. The aim of this study was to evaluate the frequency, distribution, and antimicrobial susceptibility of staphylococcal species and Clostridioides difficile isolated from the feces of free-living rodents and marsupials from two urban parks in Belo Horizonte, Brazil. During a 12-month period, fecal samples from 159 free-living animals, including 136 rodents and 23 marsupials, were collected from two urban parks in Belo Horizonte, Minas Gerais, Brazil. Staphylococcus spp. were more likely to be isolated from rodents than marsupials (p = 0.0164). Eight different staphylococcal species were isolated from 36 (26.5%) rodents and one marsupial (4.3%). S. saprophyticus (48.6%) was the most frequently isolated species, and almost a quarter of the isolates (24.3%) were resistant to at least one antimicrobial agent, four (10.8%) of which were multi-drug resistant (MDR). Two (5.4%) strains were resistant to cefoxitin and were then classified as methicillin-resistant staphylococci, and one also tested positive for the mecA gene. C. difficile was isolated from two rodents (1.5%), and one strain was toxigenic and classified as ribotype 064. One isolate was resistant to rifampicin, but both strains were susceptible to all other antimicrobials tested, including metronidazole and vancomycin. All C. difficile isolates and all staphylococcal strains resistant to antimicrobials were recovered from the same park. The present study suggests that free-living rodents in Belo Horizonte (Brazil) are mainly colonized by S. saprophyticus and may act as reservoirs of antimicrobial-resistant Staphylococcus spp. and C. difficile strains. This is the first study to evaluate the presence of staphylococci and C. difficile from free-living opossums and suggest a low fecal shedding of these organisms by these mammals.

Cattle and goats' humoral response to vaccination with Clostridium perfringens type D purified epsilon toxoids.

Herd vaccination is an important preventive measure against enterotoxemia in ruminants. Vaccination in goats should be performed every four months, and recent studies have shown that immunity in cattle lasts for less than one year. One of the mechanisms for increasing the duration of the immune response is to use purified toxoids as immunogens. The aim of the present study was to evaluate the humoral response in cattle and goats after vaccination with purified and semi-purified Clostridium perfringens type D epsilon toxoid. The following three different vaccines were used: vaccine 1 (V1), a semi-purified toxoid adsorbed to aluminum hydroxide; vaccine 2 (V2), a purified toxoid adsorbed to aluminum hydroxide; and vaccine (V3), a purified toxoid adsorbed on chitosan microparticles. Groups of cattle (n = 6-7) and goats (n = 6-7) were vaccinated on days 0 and 30, and serum samples for antitoxin titration were collected every 30 days for one-year post-vaccination. Goats were revaccinated on day 360, and their serum was evaluated on days 367 and 374. The antibody peaks ranged between 6.90 and 11.47 IU/mL in cattle and from 1.11 to 4.40 IU/mL in goats. In cattle administered with the V1 and V2 vaccines, we observed that the antibody titers were maintained above 0.2 IU/mL until the end of the experiment. In goats, V2 elicited long-lasting antibodies, and all animals maintained the protective titers for 210 days after the first dose. In conclusion, the purified toxoid vaccine with aluminum hydroxide adjuvant was able to induce strong and long-lasting humoral responses in both species and could be an alternative for improving the immunization schedule against enterotoxemia in goats and cattle.

Evaluation of an immunochromatographic test for the detection of glutamate dehydrogenase for the diagnosis of Clostridioides (Clostridium) difficile infection in dogs.

This study aimed to evaluate an immunochromatographic test used to detect glutamate dehydrogenase (GDH) for the diagnosis of Clostridium difficile infection (CDI) in dogs. Fecal samples of 119 diarrheic dogs were subjected to toxigenic culture as the "gold standard" method and to GDH detection (Ecodiagnostica, Brazil). Samples positive for toxigenic C. difficile strains and those positive in the GDH test were also subjected to A/B toxin detection using an enzyme immunoassay kit (C. difficile Tox A/B II, Techlab Inc., USA). Sensitivity, specificity, and positive and negative predictive values (PPV and NPV, respectively) were measured for GDH detection and compared with the toxigenic culture results. A total of 19 (15.9%) dogs were positive for toxigenic C. difficile. Of these, 10 (52.6%) dogs were positive for A/B toxins using the enzyme immunoassay kit and 18 (15.2%) were positive in the GDH test, leading to a sensitivity and NPV of 89.4% and 97.9%, respectively. Three animals, two of which were colonized with non-toxigenic strains, were positive for GDH, though not confirmed with CDI, resulting in a high specificity (97%) and PPV (85%). The results suggest that the lateral flow test for GDH detection could be a useful method for diagnosing CDI in dogs, similar to that previously described for humans and other animal species.

Production and purification of Clostridium perfringens type D epsilon toxin and IgY antitoxin.

The aim of this study was to purify Clostridium perfringens type D epsilon toxin and produce and purify anti-epsilon chicken immunoglobulin Y (IgY). A single-step ion exchange chromatography resulted in a high-yield and high-purity toxin, while ion exchange chromatography followed by gel filtration resulted in the highest purity of the toxin, but at a lower yield. Purified and inactivated epsilon toxin were then administered in chickens via four inoculations and IgY was obtained at a high purity and yield, with an antibody titer of 50 IU/mL and high levels of avidity (73.2%). In summary, C. perfringens type D epsilon toxin and chicken anti-epsilon IgY were successfully produced and purified, and may be used for the diagnosis of enterotoxemia caused by the epsilon toxin, as well as in potency tests of existing and future vaccines against enterotoxemia.

Clostridioides (Clostridium) difficile-associated diarrhea in equine in Minas Gerais, Brazil: clinical and microbiological characterization of six cases / Diarreia por Clostridioides (Clostridium) difficile em equinos em Minas Gerais, Brasil: caracterização clínica e microbiológica de seis casos

ABSTRACT: Clostridioides (Clostridium) difficile is the main causative agent of antimicrobial-related diarrhea in humans and a major pathogen-associated enteric disorder in foals and adult horses. Moreover, studies have suggested that animals are a possible reservoir of toxigenic C. difficile strains for humans. Despite this known importance, the epidemiology of C. difficile infection (CDI) in equine is still largely unknown. Therefore, this study described six cases of equine CDI occurring in Minas Gerais, Brazil, including the characterization of the isolates. All but one equine included in this research developed CDI after antimicrobial therapy, three of which occurred during hospitalization. Coinfection with Salmonella Heidelberg and S. Infantis was detected in three cases, making the antimicrobial treatment challenging. All animals recovered after metronidazole administration. All C. difficile isolates were susceptible to metronidazole and vancomycin, while three were resistant to moxifloxacin and two were resistant to clindamycin. The isolates were classified as RT126 (n = 4), RT078 (n = 1), and RT014/020 (n = 1), all previously reported infecting humans and animals worldwide.

RESUMO: Clostridioides (Clostridium) difficile é o principal agente envolvido em diarreias associadas ao uso de antimicrobianos em seres humanos e um enteropatógeno de grande relevância em quadros de diarreia em potros e equinos adultos. Em adição, estudos tem sugerido que animais são possíveis reservatórios de estirpes toxigênicas de C. difficile para humanos. Apesar da importância na saúde animal e humana, a epidemiologia da infecção por C. difficile (ICD) é ainda pouco conhecida. Dessa forma, o presente estudo tem como objetivo caracterizar seis casos de diarreia por C. difficile ocorridos em Minas Gerais, Brasil. Com exceção de um animal, todos os equinos incluídos no presente estudo desenvolveram ICD após antibioticoterapia, três dos quais durante a hospitalização. Coinfecção por Salmonella Heidelberg e S. Infantis foi detectada em três casos, tornando o tratamento antimicrobiano desafiador. Todos os animais recuperaram após administração de metronidazol. Os isolados obtidos no presente estudo foram sensíveis a metronidazol e vancomicina, porém três estirpes foram resistentes a moxifloxacina e duas a clindamicina. Os isolados foram classificados como ribotipos 126 (n=4), 078 (n=1) e 014/020 (n=1), todos previamente relatados em seres humanos com ICD no Brasil e em outros países.

Fecal microbiota transplantation via colonoscopy in a dog with Clostridioides (Clostridium) difficile infection / Transplante de microbiota fecal via colonoscopia em um cão com infecção por Clostridioides (Clostridium) difficile

ABSTRACT: In dogs, antimicrobial therapy for Clostridioides (Clostridium) difficile infection (CDI) is based solely on metronidazole, leaving limited treatment options in case of recurrent disease. Fecal microbiota transplantation (FMT) has been successfully used in humans with recurrent CDI, whereas the usefulness of this approach is largely unknown in dogs. In the present study, a dog with a chronic-recurring diarrhea was treated with FMT via colonoscopy. CDI was confirmed by A/B toxin detection and isolation of toxigenic C. difficile from ribotype 106, a strain also commonly associated with nosocomial infection in humans. The dog recovered well after the procedure and C. difficile was no longer isolated from its stool sample. The present research suggested that FMT could be a useful tool to treat recurrent CDI in dogs, corroborating the actual protocol in humans.

RESUMO: Em cães, a terapia antimicrobiana para infecções por Clostridioides (Clostridium) difficile é baseada apenas no uso de metronidazol, limitando as opções de tratamento nos casos de recorrência. O transplante de microbiota fecal (FMT) tem sido utilizado com sucesso em seres humanos com infecções recorrentes por C. difficile, porém a utilidade desse método é ainda amplamente desconhecida em cães. O presente trabalho relata a utilização de FMT para o tratamento de um cão com diarreia crônica-recorrente por C. difficile. A infecção foi confirmada por detecção das toxinas A/B e isolamento de uma estirpe toxigênica do ribotipo 106, linhagem comumente associada a infecção em seres humanos. Após o transplante via colonoscopia, o animal se recuperou do quadro e C. difficile não mais foi encontrado em novas amostras fecais. O presente trabalho sugere que o FMT possa ser útil para o tratamento de quadros de C. difficile em cães, corroborando protocolo atual de tratamento em seres humanos.

Evaluation of glutamate dehydrogenase (GDH) and toxin A/B rapid tests for Clostridioides (prev. Clostridium) difficile diagnosis in a university hospital in Minas Gerais, Brazil.

Clostridioides (Clostridium) difficile is responsible for most cases of nosocomial diarrhea and, despite the high prevalence of the disease worldwide, the best laboratory diagnostic approach to diagnose C. difficile infection (CDI) is a subject of ongoing debate. Although the use of multiple tests is recommended, the cost of these algorithms commonly exceeds the affordability in some countries. Thus, to improve CDI diagnosis in a university hospital in Brazil, this study analyzed two immunochromatographic tests and one enzyme immunoassay (ELISA) to evaluate the detection of glutamate dehydrogenase (GDH) and A/B toxins of C. difficile. Stool samples of 89 adult patients presenting nosocomial diarrhea during hospitalization were included. The toxigenic culture was used as the reference method. GDH detection by both commercial tests showed high sensitivity (100%) and specificity (92.1%). On the other hand, toxin-based methods showed a sensitivity between 19.2 and 57.7%. In conclusion, the results suggest that rapid tests for GDH detection are not only suitable for CDI diagnosis as screening tests but also as a single method.

Immunochromatographic test and ELISA for the detection of glutamate dehydrogenase (GDH) and A/B toxins as an alternative for the diagnosis of Clostridioides (Clostridium) difficile-associated diarrhea in foals and neonatal piglets.

Considering the lack of studies evaluating the performance of commercially available methods for diagnosis of Clostridioides (Clostridium) difficile infection (CDI) in animals, the present study aimed to assess an immunochromatographic test for detection of glutamate dehydrogenase (GDH) and A/B toxins of C. difficile, also evaluated by an ELISA kit, in foals and neonatal piglets. Intestinal contents of 47 piglets and feces of 35 foals were tested to GDH antigen and A/B toxins in a lateral flow method (Ecodiagnostica, Brazil). Also, these samples were submitted to A/B toxin detection by an ELISA kit (C. difficile Tox A/B II, Techlab Inc., USA), using the toxigenic culture (TC) as the reference method. The GDH component of the lateral flow test showed sensitivity and negative predictive value (NPV) of 100% and a high specificity in samples of piglets (82.61%) and foals (100%). Detection of A/B toxins using the lateral flow test and the ELISA resulted in a specificity of 100% in samples of both species. On the other hand, the sensibility ranged from 54.2 to 90% for the ELISA and from 12.5 to 60% for the lateral flow test for piglets' and foals' samples, respectively. In conclusion, the present work suggests that the lateral flow test for GDH detection could be a useful method for diagnosing CDI in these species. On the other hand, the low sensitivity of the lateral flow test for A/B toxins might compromise its utility in piglets.

Fecal shedding of Salmonella spp., Clostridium perfringens, and Clostridioides difficile in dogs fed raw meat-based diets in Brazil and their owners' motivation.

The present study aimed to explore the motivations of Brazilian dog owners and their knowledge about the risks related to raw meat-based diets (RMBD) as well as to evaluate important enteropathogens such as Salmonella spp., C. perfringens, and C. difficile, in feces of dogs fed different diets. The majority of the pet owners (69.3%) reported to have chosen this diet for their dogs, considering it to be more "natural". A large number of owners declared that RMBD do not pose health risks for their animals (87.9%) or humans (98.8%), even though almost one third of the respondents (34.8%) declared having at least one individual at high risk of infection in contact with RMBD-fed dogs. Stool samples from 46 RMBD-fed dogs and 192 dogs fed commercial dry feed were collected. The present study revealed that dogs fed raw meat diets were almost 30 times more likely to be positive for Salmonella spp. than dogs on a conventional diet. Some of the serovars detected were commonly associated with human salmonellosis, such as S. Typhimurium and S. Saintpaul, and were multidrug resistant. RMBD-fed dogs were more likely to be positive for C. perfringens type A (p = 0.008) and one C. perfringens type F was isolated from these animals. Two toxigenic strains (4.3%) of C. difficile were isolated only from raw meat-fed dogs, all of which were under antibiotic therapy. These toxigenic C. difficile isolates were classified as RT106/ST54 and RT600/ST149, previously associated with infection in dogs and humans. The present work revealed that the owners have a tendency to ignore or are unaware of the risks associated with raw meat diets for dogs. Also, the higher fecal shedding of important enteropathogens in dogs fed RMBD suggests that this diet poses a risk for the animals and the people in contact with them.

Isolation of Clostridium perfringens and Clostridioides difficile in diarrheic and nondiarrheic cats.

The occurrence and characteristics of Clostridioides (previously Clostridium) difficile and Clostridium perfringens in the feces of diarrheic and non-diarrheic cats was investigated. Apparently healthy animals were more likely to be positive for C. perfringens type A (p = 0.009). Two isolates (0.7%), one each from a diarrheic and an apparently healthy cat, were positive for the enterotoxin-encoding gene but negative for the NetF-encoding gene. Six toxigenic C. difficile isolates were isolated, all RT106 and ST42, which is commonly reported in humans with C. difficile infection.

Identification and Characterization of Escherichia coli, Salmonella Spp., Clostridium perfringens, and C. difficile Isolates from Reptiles in Brazil.

Considering the increasing popularity of reptiles as pets and their possible role as reservoirs of pathogenic microorganisms, the aim of this study was to isolate Escherichia coli, Salmonella spp., Clostridium perfringens, and C. difficile strains from reptiles in Brazil and to characterize the isolated strains. The characterization was based on phylogenetic typing of E. coli, identification of virulence genes of E. coli, C. perfringens, and C. difficile, serotyping of Salmonella spp., ribotyping and MLST of C. difficile and antimicrobial susceptibility test of pathogenic strains. Cloacal swabs were collected from 76 reptiles, of which 15 were lizards, 16 chelonians, and 45 snakes, either living in captivity, in the wild, or as companion animals. E. coli was isolated from 52 (68.4%) reptiles, of which 46 (88.4%) were characterized as phylogroup B1. The virulence factor CNF1 of E. coli was found in seven (9.2%) sampled animals, whereas the gene of EAST1 was found in isolates from two (2.6%) reptiles. Three isolates positive for CNF1 were resistant to cephalothin, one of which was also resistant to ciprofloxacin, trimethoprim/sulfamethoxazole, and chloramphenicol, being then classified as multidrug resistant strain (MDR). Salmonella enterica was identified in 26 (34.2%) reptiles, of which 13 belonged to the subspecies enterica. Serotypes such as S. Mbandaka, S. Panama, S. Infantis, S. Heidelberg, and S. Anatum were identified. One isolate of S. enterica subsp. houtenae was resistant to cephalothin and ciprofloxacin. C. perfringens type A was isolated from six (7.8%) animals. C. difficile was isolated from three (3.9%) reptiles. Two of these isolates were toxigenic and classified into ribotypes/MLST 081/ST9 and 106/ST42, which have been previously reported to infect humans. In conclusion, reptiles in Brazil can harbor toxigenic C. difficile and potentially pathogenic E. coli and Salmonella enterica subsp. enterica, thus representing a risk to human and animal health.

Evaluation of growth and sporulation of a non-toxigenic strain of Clostridioides difficile (Z31) and its shelf viability.

The oral administration of non-toxigenic strains of Clostridioides difficile (NTCD) is currently showing promising results for the prevention of Clostridioides difficile infection (CDI) in humans and animals, and is being considered as a possible commercial product to be used in the near future. The aim of this work was to evaluate five culture media for the growth and sporulation of one NTCD (Z31) and evaluate the viability of a lyophilized spore solution of NTCD Z31 stored at 4 °C or at 25 °C for 2 years. Reinforced clostridial medium (RCM) and brain heart infusion broth (BHI) provided the highest production of NTCD Z31 spores. In the first 6 months of the storage of the lyophilized solution, a reduction in spore count of approximately 0.3 Log10 CFU/mL was observed; however, no further significant reduction in spore count was observed up to 24 months. No difference in spore concentration was found between the two storage temperatures from 6 to 24 months of storage. The present work showed BHI and RCM to be the best choices for the growth and sporulation of NTCD Z31 and suggested that the spores of NTCD Z31 are stable for up to 2 years under both temperature conditions.

Outbreak of multidrug resistant Salmonella Typhimurium in calves at a veterinary hospital in Brazil / Surto de Salmonella Typhimurium multirresistante em bezerros em um hospital veterinário do Brasil

ABSTRACT: The present study aimed to describe and characterize a nosocomial outbreak caused by a multidrug resistant Salmonella Typhimurium in hospitalized calves at a veterinary medical teaching hospital from Brazil. Sixty-three (96.9%) calves showed lethargy, hyperthermia and profuse diarrhea and despite treatment, 26 (41.2%) animals died. Five animals were necropsied and stool samples of six calves were collected. The isolated strains were subjected to antimicrobial susceptibility test by disc-difusion method and were fingerprinted by ERIC-PCR. Macroscopic lesions suggestive of salmonellosis, such as fibrinonecrotic enteritis and hepatosplenomegaly were observed. Salmonellosis was confirmed by isolation of S. Typhimurium from stool samples and organs from seven affected animals. Six out of seven isolates of S. Typhimurium, exhibited 100% of similarity at ERIC-PCR, suggesting occurrence of nosocomial transmission of S. Typhimurium among the hospitalized calves. All but one S. Typhimurium isolated were resistant to marbofloxacin, enrofloxacin, florfenicol, oxytetracycline and trimethoprim/sulfamethoxazole, antimicrobial agents largely used for humans and animal treatment. This is the first study of a nosocomial outbreak of multidrug resistant S. Typhimurium in a veterinary hospital in Brazil and highlighted the need for preventive measures to reduce the risks for inpatients and humans in contact with animals.

RESUMO: O objetivo do presente estudo é descrever e caracterizar um surto nosocomial provocado por S. Typhimurium multirresistente em bezerros hospitalizados em um hospital escola de medicina veteriária localizado no Brasil. Sessenta e três (96,9%) bezerros apresentaram letargia, hipertermia e diarreia profusa e, apesar do tratamento, vinte e seis animais (41,2%) morreram. Cinco animais foram necropsiados e amostras fecais de seis bezerros foram coletadas. As estirpes isoladas foram submetidas a testes de susceptibilidade a antimicrobianos pelo método de disco-difusão e foram genotipadas pelo ERIC-PCR. Lesões macroscópicas sugestivas de salmonelose, como enterite fibrinonecrótica e hepatoesplenomegalia, foram observadas. Salmonelose foi confirmada pelo isolamento de S. Typhimurium em amostras fecais e órgãos de sete animais. Dos sete isolados, seis apresentaram 100% de similaridade ao ERIC-PCR, sugerindo ocorrẽncia de transmissão nosocomial de S. Typhimurium entre os bezerros hospitalizados. Com excessão de uma estirpe, todas foram resistentes a marbofloxacina, enrofloxacina, florfenicol, oxitetraciclina e trimetoprima/sulfametoxazol, agentes antimicrobianos amplamente utilizados para o tratamento humano e animal. Esse é o primeiro estudo que demonstra um surto nosocomial de estirpes de S. Typhimurium resistentes a múltiplas drogas em um hospital veterinário no Brasil, enfatizando a necessidade de medidas preventivas que reduzam os riscos aos animais hospitalizados e a pessoas que entrarem em contato com esses animais.

Comparison of humoral neutralizing antibody response in rabbits, guinea pigs, and cattle vaccinated with epsilon and beta toxoids from Clostridium perfringens and C. botulinum types C and D toxoids.

Rabbits and guinea pigs are used in the official control and validation of clostridial vaccines, but it is unknown whether the antitoxin titers obtained in these animals corroborate with the humoral response in bovine. The objective of the study was to compare the humoral antibody response of guinea pig and rabbits to those obtained in cattle vaccinated with a commercial vaccine containing Clostridium perfringens epsilon and beta, and Clostridium botulinum types C and D toxoids. This study revealed the same level of humoral response in rabbits and cattle for all four toxoids tested, including C. botulinum types C and D toxoids. In contrast, the titers of neutralizing antibodies against C. botulinum type C toxin in guinea pigs differed from those obtained in cattle. Thus, the present work suggests that the potency test for C. botulinum types C in rabbits agrees more with the humoral response in cattle than the potency test in guinea pigs, thereby making it possible to use only rabbits as models in the official control and validations of clostridial vaccines.

Rodents are carriers of Clostridioides difficile strains similar to those isolated from piglets.

Features of Clostridioides difficile transmission in swine and the role of rodents as C. difficile reservoir are not clear. To investigate if rodents can carry strains of C. difficile that are genetically similar to those isolated from swine, 97 fecal samples from neonatal piglets and 41 intestinal contents from rodents were collected in two farms. All samples were subjected to C. difficile culture and the presence of A/B toxins in piglet feces were accessed by commercial enzyme imunoassay (EIA). C. difficile isolates were typed by double- (DLST) and multi-locus sequence typing (MLST). C. difficile was isolated from 15.5% of piglets and 31.7% of rodents. Most isolates were identified as DLST type 4-4 and 17-5 (both are ST11), which were found in both rodents and piglets. Results of this study suggested that rodents may have a role on the transmission and spread of C. difficile strains to swine.