Antimicrobial susceptibility, virulence genes and genomic characterization of Trueperella pyogenes isolated from abscesses in dairy cattle

Antimicrobial efficiency of bromhexine hydrochloride against endometritis-causing Escherichia coli and Trueperella pyogenes in bovines

In this study, the main agents associated with endometritis in cows in the state of Santa Catarina, Brazil, were identified and the resistance profile and virulence mechanisms of the bacterial isolates were evaluated. Isolates of Escherichia coli and Trueperella pyogenes were tested for their biofilm forming ability and the antimicrobial action of bromhexine hydrochloride in combination with other antimicrobials. A total of 37 uterine lavage samples were collected from cows with endometritis. Of the 55 bacteria isolated, 25.4% were identified as T. pyogenes and 16.3% as E. coli. The bacterial isolates showed greater resistance to sulfamethoxazole + trimethoprim (58.2%) and tetracycline (56.3%). Among the species, E. coli showed the highest resistance rates, with 100% of isolates showing resistance to amoxicillin, streptomycin, and gentamicin. The results of the minimum inhibitory concentration for the T. pyogenes isolates showed that 91.6% of the isolates were resistant to enrofloxacin and tetracycline, and 75% were resistant to ceftiofur and sulfamethoxazole + trimethoprim. All E. coli and T. pyogenes isolates showed biofilm forming ability. The plo, fimA, and nanH genes were identified in 100% of T. pyogenes isolates. In parallel, 100% of E. coli isolates had the fimH gene, and 11.1% had the csgD gene. Bromhexine hydrochloride showed antimicrobial activity against 100% of E. coli isolates and 66.6% of T. pyogenes isolates. Furthermore, when associated with antimicrobials, bromhexine hydrochloride has a synergistic and additive effect, proving to be an option in the treatment of endometritis in cows and an alternative for reducing the use of antimicrobials.

Immunoinformatics design of novel multi-epitope vaccine against Trueperella Pyogenes using collagen adhesion protein, fimbriae, and pyolysin

Trueperella pyogenes (T. pyogenes) is an opportunistic pathogen that causes infertility, mastitis, and metritis in animals. T. pyogenes is also a zoonotic disease and is considered an economic loss agent in the livestock industry. Therefore, vaccine development is necessary. Using an immunoinformatics approach, this study aimed to construct a multi-epitope vaccine against T. pyogenes. The collagen adhesion protein, fimbriae, and pyolysin (PLO) sequences were initially retrieved. The HTL, CTL, and B cell epitopes were predicted. The vaccine was designed by binding these epitopes with linkers. To increase vaccine immunogenicity, profilin was added to the N-terminal of the vaccine construct. The antigenic features and safety of the vaccine model were investigated. Docking, molecular dynamics simulation of the vaccine with immune receptors, and immunological simulation were used to evaluate the vaccine's efficacy. The vaccine's sequence was then optimized for cloning. The vaccine construct was designed based on 18 epitopes of T. pyogenes. The computational tools validated the vaccine as non-allergenic, non-toxic, hydrophilic, and stable at different temperatures with acceptable antigenic features. The vaccine model had good affinity and stability to bovine TLR2, 4, and 5 as well as stimulation of IgM, IgG, IL-2, IFN-γ, and Th1 responses. This vaccine also increased long-lived memory cells, dendritic cells, and macrophage population. In addition, codon optimization was done and cloned in the E. coli K12 expression vector (pET-28a). For the first time, this study introduced a novel multi-epitope vaccine candidate based on collagen adhesion protein, fimbriae, and PLO of T. pyogenes. It is expected this vaccine stimulates an effective immune response to prevent T. pyogenes infection.

Molecular Mechanisms of Shigella Pathogenesis; Recent Advances

Shigella species are the main cause of bacillary diarrhoea or shigellosis in humans. These organisms are the inhabitants of the human intestinal tract; however, they are one of the main concerns in public health in both developed and developing countries. In this study, we reviewed and summarised the previous studies and recent advances in molecular mechanisms of pathogenesis of Shigella Dysenteriae and non-Dysenteriae species. Regarding the molecular mechanisms of pathogenesis and the presence of virulence factor encoding genes in Shigella strains, species of this bacteria are categorised into Dysenteriae and non-Dysenteriae clinical groups. Shigella species uses attachment, invasion, intracellular motility, toxin secretion and host cell interruption mechanisms, causing mild diarrhoea, haemorrhagic colitis and haemolytic uremic syndrome diseases in humans through the expression of effector delivery systems, protein effectors, toxins, host cell immune system evasion and iron uptake genes. The investigation of these genes and molecular mechanisms can help us to develop and design new methods to detect and differentiate these organisms in food and clinical samples and determine appropriate strategies to prevent and treat the intestinal and extraintestinal infections caused by these enteric pathogens.