Prevalence, Antibiotic Resistance, Toxin-Typing and Genotyping of Clostridium perfringens in Raw Beef Meats Obtained from Qazvin City, Iran

Antimicrobial Susceptibility and Toxin Gene Profiles of Commensal Clostridium perfringens Isolates from Turkeys in Hungarian Poultry Farms (2022-2023)

Background: The global spread of antimicrobial resistance (AMR) remains one of the greatest challenges of our time, necessitating collaboration among professionals in both the animal and public health sectors. One bacterial species that is developing AMR is Clostridium perfringens. It causes serious bacterial infections and continues to cause significant economic losses in the poultry industry. Methods: This study aimed to evaluate the antimicrobial susceptibility profiles of commensal C. perfringens strains isolated from large-scale turkey flocks in Hungary using minimum inhibitory concentration (MIC) determination. We complemented our research with polymerase chain reaction (PCR) analysis to detect the major and minor toxin genes that are characteristic of the species and to explore the potential associations between gene presence and antimicrobial resistance profiles. Results: A total of 146 commensal isolates were examined. Sensitivity to penicillin was reduced, with only 44.5% of isolates remaining susceptible, whereas 87.7% of isolates were sensitive to amoxicillin. The PCR results revealed that all isolates carried the alpha major toxin gene, 23.9% harbored the beta major toxin gene, 15.8% the beta2 minor toxin gene, 3.4% the NetB minor toxin gene, and 2.7% the epsilon major toxin gene. No statistically significant associations were observed between the presence of toxin genes and the antimicrobial susceptibility profiles of the isolates; the MIC values showed no correlation with the presence of toxin-producing genes. Conclusions:Clostridium perfringens isolates retained susceptibility to beta-lactam antibiotics, which remain the primary choice for treatment. Regular monitoring can aid in establishing temporal trends. Future studies should include larger sample sizes and employ next-generation sequencing to further investigate multidrug-resistant strains.

Combating Pathogenic Immune Evasion: Sialidase-Activated Thermally Delayed Fluorescence for Probing and Modulating Host-Pathogen Interactions

Innate immunity represents the primary defense against invasive pathogens with phagocytosis playing a central role in host defense and mediating immune and inflammatory responses. However, pathogens such as Clostridium perfringens have developed strategies to overcome phagocytic clearance. Developing molecular tools to identify and target key factors in pathogenic immune evasion can deepen our understanding of host-pathogen interactions and aid in exploring novel therapeutic strategies. As a key enzyme in the sialylation process of C. perfringens, the virulence factor sialidase is a potential target for investigating pathogenic immune evasion. Herein, a "turn-on" thermally activated delayed fluorescent probe SA-HBT-PXZ is developed as a highly selective and sensitive sialidase sensor, enabling time-resolved fluorescence imaging of C. perfringens in live bacterial cells, tissue sections, and even infected mice. Furthermore, SA-HBT-PXZ is successfully employed to screen sialidase inhibitors based on prompt and delayed fluorescence emissions. The identified lead compounds effectively inhibit the activity of sialidases from C. perfringens, leading to an increased level of differentiation of macrophages into the M1 subtype. This, in turn, enhances the phagocytosis of C. perfringens and ultimately suppresses the immune escape of the bacteria. Our study provides a potential target and lead compounds for novel therapeutic strategies against C. perfringens infections.

Alpha toxin production potential and antibiotic resistance patterns of clostridium perfringens isolates from meat samples

OBJECTIVE

This research aimed to analyze the prevalence, molecular characteristics, toxinotyping, alpha toxin production potential, and antibiotic resistance pattern of Clostridium perfringens (C. perfringens) isolates in meat samples collected from various sources.

METHODS

Sixty meat samples were screened for alpha toxin using enzyme-linked immunosorbent assay, revealing a positivity rate of 13.3%, predominantly in raw poultry meat. Subsequent culturing on Perfringens agar identified nine samples harboring characteristic C. perfringens colonies, primarily isolated from raw poultry meat. Molecular confirmation through 16S rRNA gene amplification and sequencing authenticated twelve isolates as C. perfringens, with nine strains exhibiting genetic resemblance to locally isolated strains. Toxinotyping assays targeting alpha toxin-specific genes confirmed all nine isolates as type A C. perfringens, with no detection of beta or epsilon toxin genes. Hemolytic assays demonstrated varying alpha toxin production potentials among isolates, with accession number OQ721004.1 displaying the highest production capacity. Moreover, antibiotic resistance profiling revealed multi-drug resistance patterns among the isolates.

RESULTS

The study identified distinct clusters within C. perfringens strains, indicating variations. Phylogenetic analysis delineated genetic relatedness among strains, elucidating potential evolutionary paths and divergences.

CONCLUSION

The findings underscore the need for robust surveillance and control measures to mitigate the risk of C. perfringens contamination in meat products, particularly in raw poultry meat. Enhanced monitoring and prudent antimicrobial stewardship practices are warranted in both veterinary and clinical settings to address the observed antibiotic resistance profiles and prevent foodborne outbreaks.

The hidden threat: Comprehensive assessment of antibiotic and disinfectant resistance in commercial pig slaughterhouses

The presence of antibiotic resistance genes (ARGs), disinfectant resistance genes (DRGs), and pathogens in animal food processing environments (FAPE) poses a significant risk to human health. However, knowledge of the contamination and risk profiles of a typical commercial pig slaughterhouse with periodic disinfectant applications is limited. By creating the overall metagenomics-based behavior and risk profiles of ARGs, DRGs, and microbiomes in a nine-section pig slaughterhouse, an important FAPE in China. A total of 454 ARGs and 84 DRGs were detected in the slaughterhouse with resistance genes for aminoglycosides and quaternary ammonium compounds, respectively. The entire slaughtering chain is a hotspot for pathogens, including 83 human pathogenic bacteria (HPB), with 47 core HPB. In addition, 68 high-risk ARGs were significantly correlated with 55 HPB, 30 of which were recognized as potential bacteria co-resistant to antibiotics and disinfectants, confirm a three-fold risk of ARGs, DRGs, and pathogens prevailing throughout the chain. Pre-slaughter pig house (PSPH) was the major risk source for ARGs, DRGs, and HPB. Moreover, 75 Escherichia coli and 47 Proteus mirabilis isolates showed sensitivity to potassium monopersulfate and sodium hypochlorite, suggesting that slaughterhouses should use such related disinfectants. By using whole genome multi-locus sequence typing and single nucleotide polymorphism analyses, genetically closely related bacteria were identified across distinct slaughter sections, suggesting bacterial transmission across the slaughter chain. Overall, this study underscores the critical role of the PSPH section as a major source of HPB, ARGs, and DRGs contamination in commercial pig slaughterhouses. Moreover, it highlights the importance of addressing clonal transmission and cross-contamination of antibiotic- and disinfectant-resistant bacteria within and between slaughter sections. These issues are primarily attributed to the microbial load carried by animals before slaughter, carcass handling, and content exposure during visceral treatment. Our findings provide valuable insights for One Health-oriented slaughterhouse management practices.

Prevalence and Antibiotic Resistance Profile of Clostridium perfringens Isolated from Pork and Chicken Meat in Vietnam

Clostridium perfringens is one of the most important zoonotic pathogens as it can cause food poisoning in humans and necrotic enteritis in both animals and humans. Meat, especially pork and chicken meat, is considered the main vehicle for the transmission of C. perfringens from animals to humans. The purpose of this study was to determine the prevalence, toxinotype, and antimicrobial resistance profile of C. perfringens isolated from pork and chicken meat sold in Vietnam. The isolation results showed that 15/50 (30%) of pork samples and 8/50 (16%) of chicken meat samples were contaminated with C. perfringens. The isolates exhibited their highest resistance rate to tetracycline (21/23; 91.30%) and clindamycin (10/23; 43.48%). On the contrary, their lowest resistance rates were observed in response to imipenem (2/23; 8.70%) and cefoxitin (1/23; 4.35%). In particular, 34.78% (8/23) of C. perfringens isolates were identified to be multidrug-resistant strains. The results of toxin genotyping indicated that all isolates were positive for the cpa gene and belonged to type A.

Types A and F Clostridium perfringens in healthcare wastewater from Ghana

IMPORTANCE

Clostridium perfringens causes gas gangrene and food poisoning in humans, and monitoring this bacterium is important for public health. Although whole-genome sequencing is useful to comprehensively understand the virulence, resistome, and global genetic relatedness of bacteria, limited genomic data from environmental sources and developing countries hamper our understanding of the richness of the intrinsic genomic diversity of this pathogen. Here, we successfully accumulated the genetic data on C. perfringens strains isolated from hospital effluent and provided the first evidence that predicted pathogenic C. perfringens may be disseminated in the clinical environment in Ghana. Our findings suggest the importance of risk assessment in the environment as well as the clinical setting to mitigate the potential outbreak of C. perfringens food poisoning in Ghana.

High Prevalence of Multidrug-Resistant, Biofilm-Forming Virulent Clostridium perfringens in Broiler Chicken Retail Points in Northeast India

In light of the significant public health and food safety implications associated with Clostridium perfringens, this study aimed to isolate and characterize C. perfringens in samples obtained from broiler chicken retail points in Meghalaya, northeastern India. A total of 280 samples comprising meat, intestinal contents, water, and hand swabs were processed to detect contamination by C. perfringens. The isolates were subjected to toxinotyping, antimicrobial susceptibility testing, and biofilm-forming ability test. The overall occurrence of C. perfringens was 22.5% (17.74-27.85, 95% CI) with the highest recovery from intestine samples (31%; 22.13-41.03, 95% CI), followed by meat (23%, 15.17-32.49, 95% CI) and water samples (18%, 8.58-31.44, 95% CI). Type A was the predominant toxinotype (71.43%, 58.65-82.11, 95% CI), followed by Type A with beta2 toxin (17.46%, 9.05-29.10, 95% CI), Type C (7.94%, 2.63-17.56, 95% CI), and Type C with beta2 toxin (3.17%, 0.39-11.0, 95% CI). Nearly all (95.24%) isolates were multidrug resistant and 68.25% were biofilm formers. The predominance of multidrug-resistant and virulent Type A and Type C C. perfringens in retail broiler meat and intestines in the tribal-dominated northeastern region of India is of great concern from food safety and public health perspectives.

Complete genome analysis and biological characterization of a novel phage vB_CP_qdyz_P5 with lytic activity against Clostridium perfringens

Clostridium perfringens, a common foodborne pathogen, exhibit high-stress resistance. The prevailing reliance on antibiotics in the farming industry for its prevention and control has led to increasing concerns over antibiotic residue and bacterial resistance. Bacteriophages that possess specific lytic activity against C. perfringens are of significant interest. Here, a novel C. perfringens phage, named vB_CP_qdyz_P5, was isolated and characterized. The phage displayed high stability at temperatures below 70 °C and pH levels ranging from 4 to 12. Genome analysis revealed that vB_CP_qdyz_P5 has a double-stand DNA of 18,888 bp with a G + C composition of 28.8%. Among the 27 identified opening reading frames (ORFs), eight were found to be functional genes. BLASTn analysis showed that vB_CP_qdyz_P5 is closely related to phage DCp1, with a genome homology coverage of 83%. Phylogenetic analysis indicated that vB_CP_qdyz_P5 may be a novel phage of the family Guelinviridae, Susfortunavirus. This study provides important preliminary information for further research on the potential use of vB_CP_qdyz_P5 in protecting against C. perfringens and maintaining intestinal health.

Synergistic Antibiotic Activity of Ricini Semen Extract with Oxacillin against Methicillin-Resistant Staphylococcus aureus

Resistant bacteria are emerging as a critical problem in the treatment of bacterial infections by neutralizing antibiotic activity. The development of new traditional mechanisms of antibiotics is not the optimal solution. A more reasonable approach may be to use relatively safe, plant-based compounds in combination with conventional antibiotics in an effort to increase their efficacy or restore their activity against resistant bacteria. We present our study of mixing Ricini Semen extract, or its constituent fatty acids, with oxacillin and testing the effects of each on the growth of methicillin-resistant Staphylococcus aureus. Changes in the cell membrane fluidity of methicillin-resistant S. aureus were found to be a major component of the mechanism of synergistic antibiotic activity of Ricini Semen extract and its constituent fatty acids. In our model, changes in cellular membrane fluidity disrupted the normal function of bacterial signaling membrane proteins BlaR1 and MecR1, which are known to detect oxacillin, and resulted in the incomplete expression of penicillin-binding proteins 2a and β-lactamase. Utilizing the mechanism presented in this study presents the possibility of developing a method for treating antibiotic-resistant bacteria using traditional antibiotics with plant-based compounds.

Intra-species diversity of Clostridium perfringens: A diverse genetic repertoire reveals its pathogenic potential

Clostridium perfringens is the causative agent of many enterotoxic diseases in humans and animals, and it is present in diverse environments (soil, food, sewage, and water). Multilocus Sequence Typing (MLST) and Whole Genome Sequencing (WGS) have provided a general approach about genetic diversity of C. perfringens; however, those studies are limited to specific locations and often include a reduced number of genomes. In this study, 372 C. perfringens genomes from multiple locations and sources were used to assess the genetic diversity and phylogenetic relatedness of this pathogen. In silico MLST was used for typing the isolates, and the resulting sequence types (ST) were assigned to clonal complexes (CC) based on allelic profiles that differ from its founder by up to double-locus variants. A pangenome analysis was conducted, and a core genome-based phylogenetic tree was created to define phylogenetic groups. Additionally, key virulence factors, toxinotypes, and antibiotic resistance genes were identified using ABRicate against Virulence Factor Database (VFDB), TOXiper, and Resfinder, respectively. The majority of the C. perfringens genomes found in publicly available databases were derived from food (n = 85) and bird (n = 85) isolates. A total of 195 STs, some of them shared between sources such as food and human, horses and dogs, and environment and birds, were grouped in 25 CC and distributed along five phylogenetic groups. Fifty-three percent of the genomes were allocated to toxinotype A, followed by F (32%) and G (7%). The most frequently found virulence factors based on > 70% coverage and 99.95% identity were plc (100%), nanH (99%), ccp (99%), and colA (98%), which encode an alpha-toxin, a sialidase, an alpha-clostripain, and a collagenase, respectively, while tetA (39.5%) and tetB (36.2%), which mediate tetracycline resistance determinants, were the most common antibiotic resistance genes detected. The analyses conducted here showed a better view of the presence of this pathogen across several host species. They also confirm that the genetic diversity of C. perfringens is based on a large number of virulence factors that vary among phylogroups, and antibiotic resistance markers, especially to tetracyclines, aminoglycosides, and macrolides. Those characteristics highlight the importance of C. perfringens as a one of the most common causes of foodborne illness.

Bioengineered Probiotics: Synthetic Biology Can Provide Live Cell Therapeutics for the Treatment of Foodborne Diseases

The rising prevalence of antibiotic resistant microbial pathogens presents an ominous health and economic challenge to modern society. The discovery and large-scale development of antibiotic drugs in previous decades was transformational, providing cheap, effective treatment for what would previously have been a lethal infection. As microbial strains resistant to many or even all antibiotic drug treatments have evolved, there is an urgent need for new drugs or antimicrobial treatments to control these pathogens. The ability to sequence and mine the genomes of an increasing number of microbial strains from previously unexplored environments has the potential to identify new natural product antibiotic biosynthesis pathways. This coupled with the power of synthetic biology to generate new production chassis, biosensors and “weaponized” live cell therapeutics may provide new means to combat the rapidly evolving threat of drug resistant microbial pathogens. This review focuses on the application of synthetic biology to construct probiotic strains that have been endowed with functionalities allowing them to identify, compete with and in some cases kill microbial pathogens as well as stimulate host immunity. Weaponized probiotics may have the greatest potential for use against pathogens that infect the gastrointestinal tract: Vibrio cholerae, Staphylococcus aureus, Clostridium perfringens and Clostridioides difficile. The potential benefits of engineered probiotics are highlighted along with the challenges that must still be met before these intriguing and exciting new therapeutic tools can be widely deployed.