Antibiotic resistance, genome analysis and further safe traits of Clostridium perfringens ICVB082; a strain capable of producing an inhibitory compound directed only against a closely related pathogenic strain

Preventive and Therapeutic Potential of Streptococcus cristatus CA119 in Experimental Periodontitis in Rats

Periodontitis is an inflammatory condition of the oral cavity caused by a mixed infection of various bacteria, which not only severely affects the alveolar bone and connective tissues but also displays potential correlations with distal intestinal inflammation. In this study, we aimed to elucidate the therapeutic effects of Streptococcus cristatus CA119 on experimental periodontitis in rats and its impact on intestinal morphology. The results demonstrate that CA119 is capable of colonizing the oral cavity and exerting antagonistic effects on Porphyromonas gingivalis and Fusobacterium nucleatum, thus leading to a significant reduction in the oral pathogen load. Following CA119 intervention, there was a significant alleviation of weight loss in rats induced by periodontitis (P < 0.001). CA119 also regulated the expression of IL-6 (P < 0.05), IL-1β (P < 0.001), IL-18 (P < 0.001), COX-2 (P < 0.001), iNOS (P < 0.001), and MCP-1 (P < 0.01) in the gingival tissue. Additionally, CA119 reduced oxidative stress levels in rats and enhanced their antioxidant capacity. Microcomputed tomography (micro-CT) and histological analysis revealed that CA119 significantly reduced alveolar bone loss and reversed the downregulation of OPG/RANKL (P < 0.001). Furthermore, CA119 exhibited a significant protective effect against intestinal inflammation induced by periodontal disease and improved the colonic morphology in rats. In conclusion, this study demonstrates the role of CA119 as a potential oral probiotic in the prevention and treatment of experimental periodontitis, underscoring the potential of probiotics as a complementary approach to traditional periodontal care.

Protective Effects of Novel Lactobacillaceae Strains Isolated from Chicken Caeca against Necrotic Enteritis Infection: In Vitro and In Vivo Evidences

The present study aimed to show the benefits of novel lactic acid bacteria (LAB) strains isolated from the caeca of healthy chickens. These novel strains, identified as Limosilactobacillus reuteri and Ligilactobacillus salivarius, displayed high levels of lactic acid production, capability of biofilm formation, high aggregation and adhesion scores, and significant survival rates under conditions mimicking the chicken gastrointestinal tract (GIT). In addition, these novel Lactobacillaceae isolates were neither hemolytic nor cytotoxic. In vivo trials were able to establish their ability to reduce necrotic enteritis. Notably, a significant weight gain was registered, on day 10 of treatment, in the group of chickens fed with a mixture of L. reuteri ICVB416 and L. salivarius ICVB430 strains, as compared with the control group. This group has also shown a reduced number of lesions in the gut compared with other infected chicken groups. This study provides in vitro and in vivo evidence supporting the benefits of these novel Lactobacillaceae isolates for their use in poultry livestock as protective cultures to control the bacterial necrotic enteritis (NE) Clostridium perfringens.

Potentiating effects of leaderless enterocin DD14 in combination with methicillin on clinical methicillin-resistant Staphylococcus aureus S1 strain

Biofilm formation by pathogenic bacteria as well as their resilience to antibiotic treatments are a major health problem. Here, we sequenced and analyzed the genome of the clinical methicillin-resistant Staphylococcus aureus S1 (MRSA-S1) strain and established its sensitivity to the combination of methicillin and the leaderless two peptides enterocin DD14 (EntDD14). Such sensitivity was assessed in vitro based on the MIC/FIC values as well as on killing curves experiments. Moreover, combination of EntDD14 and methicillin was able to reduce the biofilm formation of Staphylococcus aureus S1 of about ∼30 %. Interestingly, genes thought to be involved in the virulence of MRSA-S1, like nuc and pvl which code, respectively, for nuclease and Panton-Valentine leucocidin, were shown to be downregulated following treatment with EntDD14 and methicillin. Similar effects were registered for other genes such as cflA, cflB and icaB, coding for bacterial ligands clumping factors A, B and intercellular adhesion factor respectively. All these data, suggest that combinations of bacteriocins and antibiotics are useful as a backup for treatment of bacterial infections.

Biodiversity and Phylogenetic Relationships of Novel Bacteriocinogenic Strains Isolated from Animal's Droppings at the Zoological Garden of Lille, France

This study aimed at exploring droppings of animals living in captivity in the zoological garden (Zoo) of Lille (France), as novel sources of bacteriocinogenic strains. A collection of 295 bacterial isolates was constituted from droppings of capybara, alpaca, muntjac, zebra, tapir, rhinoceros, binturong, armadillo, saki monkey and cockatoo. Of 295 isolates, 51 exhibited antagonism against a panel of pathogenic target bacteria like Escherichia coli MC4100, Clostridium perfringens DSM 756 and Salmonella enterica subsp. enterica Newport ATCC6962. Remarkably, within this collection, only 2 Gram-negative bacilli exhibited activity against E. coli MC4100 strain used as target organism. Then, the 16S rDNA sequencing revealed these thereafter cited species, Pediococcus pentosaceus, Weissella cibaria, E. coli, Lactobacillus reuteri, Enterococcus hirae and Enterococcus faecalis. Characterization of this antagonism has revealed 11 strains able producing extracellular protease-sensitive inhibitory compounds. These strains included E. coli ICVB442 and ICVB443, Ent. faecalis ICVB472, ICVB474, ICVB477 ICVB479, ICVB481, ICVB497 and ICVB501 and Ped. pentosaceus ICVB491 and ICVB492. The genomes of the 5 most promising bacteriocinogenic strains were sequenced and analysed with Bagel4 software. Afterwards, this bioinformatics analysis permitted to locate genes encoding bacteriocins like colicin Y (E. coli), enterocin 1071A, enterocin 107 B (Ent. faecalis) and penocin A (Ped. pentosaceus), associating the above-mentioned antibacterial activity of proteinaceous nature to possible production of bacteriocins. All these results enabled us to select different bacteriocinogenic strains for a further characterization in terms of beneficial traits.

Densitometric analysis of rep-PCR data: Insight into genetic variability and transmission of Clostridium perfringens typed with an improved multiplex PCR

An epidemiological study was conducted in North-East India (part of Indo-Burma biodiversity hotspot) to better understand the distribution, diversity, and transmission of Clostridium perfringens among livestock, pets, wild animals (captive), and humans. A total of 160 C. perfringens isolates were recovered from 642 diarrhoeic faecal samples with an isolation rate of 24.92%. Isolation rate was the highest among captive wild animals (37.5%) followed by dog (34.6%), human (33.8%), pig (32.7%), cattle (20.8%), goat (18.3%) and poultry (9.3%). Isolates were toxin typed using a seven gene multiplex PCR designed for simultaneous detection of cpa, cpb, cpb2, etx, iap, cpe and netB. The majority of isolates, 128 (80%) were of type A, followed by 17 (10.62%), 5 (3.12%), 4 (2.5%), 3 (1.87%), 2 (1.25%) and 1 (0.63%) isolates of type C, D, E, G, F and B, respectively. Beta 2 toxin gene was present in 65 (50%) of type A isolates, followed by 7 (41.2%), 4 (80%), 1(25%), and 1 (100%) of type C, D, G and B isolates, respectively. Beta 2 toxin has a high prevalence among dogs (28.6%), cattle (27.3%), and pig (20.8%) compared to humans, goat, wild animals, and poultry (1.2-14.3%). The prevalence of CPE and NetB toxin-positive strains was low, with only 3 (1.8%) and 5 (3.1%) isolates, respectively. Association of C. perfringens with diarrhoea in Civet Cat, Golden Langur, and Gray Langur has been reported for the first time. The genetic diversity and transmission of isolates were investigated using automated rep-PCR (Diversilab®, bioMérieux) using two densitometry-based matrices: modified Kullback-Leibler (KL) and Pearson's correlation (PC). The PC and modified KL matrices formed three distinct clusters with 59% and 27.2% similarity, respectively. C. perfringens diversity and transmission were best studied using modified KL matrix that placed more emphasis on the presence of bands rather than intensity. However, the PC method was found to be more suitable for differentiating strains within a toxin type, with slightly higher D-values.