Major and minor toxins of Clostridium perfringens isolated from healthy and diseased sheep

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.

Longitudinal Investigation of the Gut Microbiota in Goat Kids from Birth to Postweaning

Early microbial colonization in the gut impacts animal performance and lifelong health. However, research on gut microbial colonization and development in young ruminants, especially after weaning, is currently limited. In this study, next-generation sequencing technology was performed to investigate the temporal dynamic changes of the microbial community in the jejunum and colon of goats at 1, 7, 14, 28, 42, 56, 70, and 84 days (d) of age. As age increased, significant increases in microbial diversity, including the number of Observed OTUs and the Shannon Index, were observed in both the jejunum and colon. Regarding beta diversity, significant shifts in community membership and structure from d1 to d84 were observed based on both Bray–Curtis and Jaccard distances. With increasing age, dominant genera in the jejunum shifted from Lactobacillus to unclassified Ruminococcaceae, unclassified Lachnospiraceae and unclassified Clostridiales through starter supplementation, whereas colonic dominant genera changed from Lactobacillus and Butyricicoccus, within d1–d28, to unclassified Ruminococcaceae, unclassified Clostridiales and Campylobacter after solid diet supplementation. The linear discriminant analysis (LDA) effect size (LEfSe) analysis revealed bacterial features that are stage-specific in the jejunum and colon, respectively. In the jejunum and colon, a significantly distinct structure and membership of the microbiota was observed across all ages. The growth stage-associated microbiota in each gut compartment was also identified as a marker for biogeography. Our data indicate the temporal and spatial differences of the gut microbiota in goats are important for their performance and health. Early microbial colonization can influence microbial composition in later life (e.g., post-weaning phase). This study provides insights that the temporal dynamics of gut microbiota development from newborn to post-weaning can aid in developing feeding strategies to improve goat health and production.

Biological Toxins as the Potential Tools for Bioterrorism

Biological toxins are a heterogeneous group produced by living organisms. One dictionary defines them as "Chemicals produced by living organisms that have toxic properties for another organism". Toxins are very attractive to terrorists for use in acts of bioterrorism. The first reason is that many biological toxins can be obtained very easily. Simple bacterial culturing systems and extraction equipment dedicated to plant toxins are cheap and easily available, and can even be constructed at home. Many toxins affect the nervous systems of mammals by interfering with the transmission of nerve impulses, which gives them their high potential in bioterrorist attacks. Others are responsible for blockage of main cellular metabolism, causing cellular death. Moreover, most toxins act very quickly and are lethal in low doses (LD50 < 25 mg/kg), which are very often lower than chemical warfare agents. For these reasons we decided to prepare this review paper which main aim is to present the high potential of biological toxins as factors of bioterrorism describing the general characteristics, mechanisms of action and treatment of most potent biological toxins. In this paper we focused on six most danger toxins: botulinum toxin, staphylococcal enterotoxins, Clostridium perfringens toxins, ricin, abrin and T-2 toxin. We hope that this paper will help in understanding the problem of availability and potential of biological toxins.