Prevalence and characterization of Clostridium perfringens isolated from different chicken farms in China

Clostridium perfringens in the Intestine: Innocent Bystander or Serious Threat?

The Clostridium perfringens epidemic threatens biosecurity and causes significant economic losses. C. perfringens infections are linked to more than one hundred million cases of food poisoning annually, and 8-60% of susceptible animals are vulnerable to infection, resulting in an economic loss of more than 6 hundred million USD. The enzymes and toxins (>20 species) produced by C. perfringens play a role in intestinal colonization, immunological evasion, intestinal micro-ecosystem imbalance, and intestinal mucosal disruption, all influencing host health. In recent decades, there has been an increase in drug resistance in C. perfringens due to antibiotic misuse and bacterial evolution. At the same time, traditional control interventions have proven ineffective, highlighting the urgent need to develop and implement new strategies and approaches to improve intervention targeting. Therefore, an in-depth understanding of the spatial and temporal evolutionary characteristics, transmission routes, colonization dynamics, and pathogenic mechanisms of C. perfringens will aid in the development of optimal therapeutic strategies and vaccines for C. perfringens management. Here, we review the global epidemiology of C. perfringens, as well as the molecular features and roles of various virulence factors in C. perfringens pathogenicity. In addition, we emphasize measures to prevent and control this zoonotic disease to reduce the transmission and infection of C. perfringens.

Emergence of genetic diversity and multi-drug resistant Clostridium perfringens from wild birds

BACKGROUND

Clostridium perfringens (C. perfringens) is an important zoonotic microorganism that can cause animal and human infections, however information about the prevalence status in wild birds of this pathogenic bacterium is currently limited.

RESULT

In this study, 57 strains of C. perfringens were isolated from 328 fecal samples of wild birds. All the isolates were identified as type A and 70.18% of the isolates carried the cpb2 gene. Antimicrobial susceptibility testing showed that and 22.80% of the isolates were classified as multidrug-resistant strains. The MLST analysis of the 57 isolates from wild birds was categorized into 55 different sequence types (STs) and clustered into eight clonal complexes (CCs) with an average of 20.1 alleles and the Simpson Diversity index (Ds) of 0.9812, and revealed a high level of genetic diversity within the C. perfringens populations. Interestingly, the isolates from swan goose were clustered in the same CC while isolates from other bird species were more scattered suggesting that a potential difference in genetic diversity among the C. perfringens populations associated with different bird species.

CONCLUSION

C. perfringens exhibits a wide range of host adaptations, varying degrees of antimicrobial resistance, and a high degree of genetic diversity in wild birds. Understanding the prevalence, toxin type, antimicrobial resistance, and genetic diversity of C. perfringens in wildlife populations is essential for developing effective strategies for disease control and management.

Cell-Free Supernatant of Bacillus subtilis G2B9-Q Improves Intestinal Health and Modulates Immune Response to Promote Mouse Recovery in Clostridium perfringens Infection

Clostridium perfringens is one of the critical causative agents causing diarrhea in piglets, with significant economic losses to the pig industry. Under normal gut microbiota homeostasis and well-managed barns, diarrhea caused by C. perfringens could be controlled. Some reports show that probiotics, such as Bacillus subtilis, are beneficial in preventing necrotic enteritis (NE) in chickens, but few reports on piglets. Clostridium perfringens was found in the piglets' diarrhea with intestinal microbiota dysbiosis in our survey. Bacillus subtilis G2B9-Q, which was isolated from the feces of healthy pigs, was found to have anti-Clostridium activity after screening. Clostridium perfringens was used to challenge mice by intraperitoneal injection for modeling to evaluate the anti-infective activity of cell-free supernatant (CFS) of B. subtilis G2B9-Q and different concentrations of B. subtilis G2B9-Q by oral administration. The results showed that G2B9-Q can mitigate intestinal lesions caused by C. perfringens infection, reduce inflammatory reactions, and modulate intestinal microbiota. The CFS of G2B9-Q can alleviate the pathological damage of intestinal tissues caused by C. perfringens infection, reduce the concentration of TNF-α and IL-10 in the sera of mice, as well as the relative expression levels of alpha toxin (CPA), perfringolysin O (PFO) toxin, IL-10, IL-22, and TNF-α in the jejunum and colon tissues, and alleviate the changes in gut microbiota structure caused by C. perfringens infection, which showed better therapeutic effects and indicated that the metabolites of G2B9-Q are essential mediators for their beneficial effects. Therefore, the CFS of G2B9-Q could potentially replace antibiotics in treating C. perfringens infection.

Characterization and multilocus sequence typing of Clostridium perfringens isolated from patients with diarrhoea and food poisoning in Tai'an region, China

OBJECTIVES

Clostridium perfringens (C. perfringens) is a significant opportunistic pathogen. This study aims to examine the occurrence of C. perfringens in patients with diarrhoea and food poisoning and compare the genetic similarities with strains found in poultry retail markets and poultry farms in the same city (Tai'an, China).

METHODS

Clostridium perfringens was isolated from 30 human faecal samples and genotyped using multiplex PCR. The antimicrobial susceptibility test was conducted using the Kirby-Bauer disk diffusion method. Genetic relationships were analysed through Multi-locus sequence typing (MLST) and Phylogenetic analysis.

RESULTS

The positive rate of C. perfringens was found to be 96.67%. Among the positive samples, 91.67% of the faecal samples from patients with food poisoning contained type F strains of C. perfringens, while only 16.67% of the samples from diarrhoea cases contained type F. The drug susceptibility test revealed that the majority of isolates displayed broad-spectrum antimicrobial resistance. Out of the 57 isolates tested for drug susceptibility, 89.47% demonstrated resistance to at least three antibiotics. The MLST results indicated that strains originating from the same host and environment tended to be more closely related. However, certain strains associated with food poisoning and diarrhoea in patients shared the same ST and CC as some strains found in the retail market. These strains were also found to be phylogenetically similar to some retail market strains, suggesting potential risks to human health.

CONCLUSIONS

Therefore, it is crucial to enhance the management of poultry retail markets in order to mitigate these associated risks.

Animal Model Studies, Antibiotic Resistance and Toxin Gene Profile of NE Reproducing Clostridium perfringens Type A and Type G Strains Isolated from Commercial Poultry Farms in China

Poultry necrotic enteritis (NE) is a complex and multifactorial disease caused by Clostridium perfringens types. Earlier, the disease was prevented and/or controlled through the addition of in-feed antibiotics and antimicrobial growth promoters (AGPs). The ban on the use of these agents as feed additives has been a major reason for re-emergence of this disease leading to huge economic losses to the world poultry industry. Understanding the pathogenesis of NE by developing an effective experimental model remains challenging and lacks consistency owing to the involvement of several critical factors involved in causing lesions of disease in the field. In this study, locally characterized C. perfringens types, i.e., ACP (toxinotype A), and GCP (toxinotype G), obtained from NE outbreaks on commercial farms in China (2020–2022), were used to experimentally induce NE in Specific-Pathogen-Free (SPF) chicks. The lesion scores observed on day 20 were 1.9 ± 1.10 (GCP strain) and 1.5 ± 1.08 (ACP strain), and both had significant difference as compared to the control group. The inclusion of fishmeal in addition to oral clostridial dose, i.e., fishmeal (day 7 onward) + Clostridia (7.5 × 108 cfu/mL consecutively for 04 days) induced a lesion score of 2.0 ± 1.15 in respective groups. Use of coccidia (Eimeria necatrix) on day 9 followed by clostridia challenge enhanced the lesion scores to 2.5 ± 1.08 and 2.2 ± 1.23 for type G and type A strains, respectively. When both predisposing factors (coccidia + fish meal) were given together, i.e., fishmeal (day 7 onward) and coccidia (day 9) along with clostridia, the lesion scores were 3.2 ± 1.22 (GCP + coccidia + fish meal) and 3.0 ± 1.15 (ACP + coccidia + fish meal). These results were significantly different from group 1 (ACP) and 2 (GCP), in which only C. perfringens was used to induce NE. The clinical signs as well as histopathological lesions in experimentally induced groups were found similar as reported in the literature. The two type G strains identified in this study were also used for susceptibility testing against various drugs. Both strains were found to be resistant to amikacin, doxycycline, metronidazole, neomycin, nystatin, polymyxin B, streptomycin, and tetracycline. Variable susceptibility was seen against ceftriaxone, florfenicol, gentamicin, and kanamycin drugs. Amoxicillin, ampicillin, cefotaxime, ciprofloxacin, enrofloxacin, ofloxacin, and penicillin were effective drugs based upon their low level of resistance and therefore they might be preferred over other antimicrobial agents for proper treatment/prophylaxis of NE infections. Further studies are needed to study the pathogenesis of NE in detail in experimentally induced models along with continuous monitoring of the resistance pattern of C. perfringens strains in the field.

Antimicrobial susceptibility and multilocus sequence typing of Clostridium perfringens isolated from yaks in Qinghai-Tibet plateau, China

Clostridium perfringens (C. perfringens) is an opportunistic pathogen that cause necrotic enteritis, food poisoning and even death in animals. In this study, we explored the prevalence, antibiotic resistance and genetic diversity of Clostridium perfringens isolated from yak in the Qinghai-Tibet plateau, China. A total of 744 yak fecal samples were collected and assessed for toxin genes, antimicrobial susceptibility and multilocus sequence typing (MLST). Results indicated that 144 out of 744 (19.35%) yak fecal samples were tested to be positive for C. perfringens, 75% (n = 108, 108/144) were C. perfringens type A, 17.36% (n = 25, 25/144) were C. perfringens type C, 2.78% (n = 4, 4/144) were C. perfringens type D, and 4.86% (n = 7, 7/144) were C. perfringens type F. In addition, 2.78% (n = 4, 4/144) of the isolates were positive for cpb2 toxin gene. Antimicrobial susceptibility testing revealed that 98.61% (142/144) of the isolates showed multiple-antibiotic resistance. According to MLST and phylogenetic tree, 144 yak-derived C. perfringens isolates had an average of 12.95 alleles and could be divided into 89 sequence types (STs) and clustered in 11 clonal complexes (CCs). The most of isolates belong to type A with a considerable genetic diversity, having Simpson index up to 0.9754. MLST and phylogenetic analysis showed that the isolates under the same clade came from multiple regions. Cross-transmission among isolates and interconnectedness were observed in the genetic evolution. According to the study, the most of the isolates exhibited broad-spectrum antibacterial resistance, diverse alleles, and multiple lethal toxin genes of C. perfringens.