Pathogenicity and Virulence of Trueperella pyogenes: A Review

Gut Microbiota Mediate Plutella xylostella Susceptibility to Bt Cry1Ac Protoxin and Exopolysaccharides

Exopolysaccharides (EPSs) are carbohydrate polymers that are synthesized and secreted into the extracellular during the growth of microorganisms. Bacillus thuringiensis (Bt) is a type of entomopathogenic bacterium, that produces various insecticidal proteins and EPSs. In our previous study, the EPSs produced by Bt strains were first found to enhance the toxicity of insecticidal crystal proteins against Plutella xylostella. However, the response of the intestinal bacterial communities of P. xylostella under the action of EPSs is still unelucidated. In this study, 16S rRNA amplicon sequencing was used to characterize the intestinal bacterial communities in P. xylostella treated with EPSs alone, Cry1Ac protoxin alone, and both the Cry1Ac protoxin and EPSs. Compared with the control group, alpha diversity indices, the Chao1 and ACE indices were significantly altered after treatment with EPSs alone, and no significant difference was observed between the groups treated with Cry1Ac protoxin alone and Cry1Ac protoxin + EPSs. However, compared with the gut bacterial community feeding on Cry1Ac protoxin alone, the relative abundance of 31 genera was significantly changed in the group treated with Cry1Ac protoxin and EPSs. The intestinal bacteria, through the oral of Cry1Ac protoxin and EPSs, significantly enhanced the toxicity of the Cry1Ac protoxin towards the axenic P. xylostella. In addition, the relative abundance of the 16S rRNA gene in the chloroplasts of Brassica campestris decreased after adding EPSs. Taken together, these results show the vital contribution of the gut microbiota to the Bt strain-killing activity, providing new insights into the mechanism of the synergistic insecticidal activity of Bt proteins and EPSs.

Minimal Impact on the Resistome of Children in Botswana After Azithromycin Treatment for Acute Severe Diarrheal Disease

BACKGROUND

Macrolide antibiotics, including azithromycin, can reduce under 5 years of age mortality rates and treat various infections in children in sub-Saharan Africa. These exposures, however, can select for antibiotic-resistant bacteria in the gut microbiota.

METHODS

Our previous randomized controlled trial (RCT) of a rapid-test-and-treat strategy for severe acute diarrheal disease in children in Botswana included an intervention (3-day azithromycin dose) group and a control group that received supportive treatment. In this prospective matched cohort study using stools collected at baseline and 60 days after treatment from RCT participants, the collection of antibiotic resistance genes or resistome was compared between groups.

RESULTS

Certain macrolide resistance genes increased in prevalence by 13%-55% at 60 days, without differences in gene presence between the intervention and control groups. These genes were linked to tetracycline resistance genes and mobile genetic elements.

CONCLUSIONS

Azithromycin treatment for bacterial diarrhea for young children in Botswana resulted in similar effects on the gut resistome as the supportive treatment and did not provide additional selective pressure for macrolide resistance gene maintenance. The gut microbiota of these children contains diverse macrolide resistance genes that may be transferred within the gut upon repeated exposures to azithromycin or coselected by other antibiotics.

CLINICAL TRIALS REGISTRATION

NCT02803827.

Bacterial community structure of Physalis peruviana L. fruit exocarp and the presence of pathogens with possible implications on food safety

Introduction

Cape gooseberry (Physalis peruviana L.) is a wellconsumed crop in Ecuador, whose fruits are abundant in bioactive molecules. Its rapid post-harvest deterioration and safety limit its market potential.

Methodology

To gather baseline data on the prevalence of bacterial taxa among groups, we employed 16S ribosomal RNA (16S rRNA) amplicon gene sequencing to detect changes in the bacterial community structure in cape gooseberry fruits harvested from an organic farm production system (# 270 samples x two ripeness stages), and fruits obtained from an open-air market (#270).

Results

This is the first report of bacterial taxa inhabiting cape gooseberry fruits. Shannon's diversity index revealed that the fruits purchased from the market and the unripe stage had the highest level of bacterial diversity (average Shannon indices of 3.3 and 3.1) followed by those collected from the field at the mature ripe stage (2.07). Alpha diversity analysis indicated that there were no significant differences in the number of taxa or evenness within the sample, whereas there was a significant difference in beta diversity between the groups. Rhizobiaceae was the most abundant family in fruits originating from the field regardless of the ripe stage, while Acetobacteraceae, Pseudomonadaceae, Fusobacteriaceae, Bacteroidaceae, and Erwiniaceae were the most abundant families in the market group. At the genus level, Liberibacter was the most abundant phytopathogen in fruits originating from the field, while Gluconobacter was the most abundant in samples collected from the market. The phytopathogen Candidatus_Liberibacter was the most abundant in samples collected from the field, while the fruits purchased from the market stands contained opportunistic enteric pathogens such as Escherichia vulneris, Klebsiella pneumoniae, and K. variicola, their relative abundance varied with the sample. In addition, potential pathogens of animal origin such as Fusobacterium necrophorum, Porphyromonas levii, Helcococcus ovis, and Trueperella pyogenes were found in almost all samples at varying relative abundance.

Conclusion

Our study provides basic information on the microbiome of cape gooseberries from agriculture fields to the table along with the detection of several pathogenic microorganisms with possible impact on food safety and public health therefore, strategies for reducing bacterial contamination in both farm and retail markets are compulsory.

Whole genome-based antimicrobial resistance, virulence, and phylogenetic characteristics of Trueperella pyogenes clinical isolates from humans and animals

Trueperella pyogenes is an opportunistic zoonotic bacterial pathogen, whose antimicrobial resistance, virulence, and genetic relatedness between strains from animals and humans are barely studied. These characteristics were therefore analyzed for clinical T. pyogenes strains from 31 animals of 11 different species and 8 humans determining their complete circular genome sequence and antimicrobial susceptibility. The MICs of 19 antimicrobials including 3 antiseptics correlated to the resistance genes identified in silico within the genomes revealing a predominance of resistance to streptomycin (aadA9), sulfamethoxazole (sul1), and tetracycline (tet(33), tet(W/N/W)) among strains from humans and cattle. Additional resistance genes (erm(X), erm(56), cmx, drfA1, aadA1, aph(3'')-Ib (strA), aph(6)-Id (strB), aac(3)-IVa, aph(4)-Ia) were found only sporadically. The resistance genes were localized on genetic elements integrated into the chromosome. A cgMLST-based phylogenetic analysis revealed two major clusters each containing genetically diverse strains. The human strains showed the closest relatedness to strains from cattle. Virulence genes coding for fimbriae (fimA, fimC), neuroamidase (nanP, nanH), pyolysin (plo), and collagen binding protein (cbpA) were identified in strains from different hosts, but no correlation was observed between virulence factors and strain origin. The existence of resistance genes typically found in Gram-negative bacteria within the Gram-positive T. pyogenes indicates a wider capacity to adapt to antimicrobial selective pressure. Moreover, the presence of similar antimicrobial resistance profiles found in cattle and human strains as well as their closest relatedness suggests common zoonotic features and cattle as the potential source for human infections.

First isolation and whole-genome sequencing of Trueperella abortisuis from a goat in Canada

Objective

The present study reports the first isolation and whole-genome sequencing of a Trueperella abortisuis bacterium from a goat.

Animals and sample

The T. abortisuis was isolated from the uterus of a goat following an abortion.

Procedure

The T. abortisuis was identified by pure culture phenotype and MALDI-TOF analysis and further characterized by whole-genome sequencing.

Results

This isolate was reliably identified as T. abortisuis and showed similar properties to type strain T. abortisuis DSM 19515T, which was recovered from a sow following an abortion. The assembled genome of this isolate was 2 564 866 bp long with a GC content of 63.9%. A total of 30 virulence-related genes were determined, suggesting the pathogenic potential of this organism.

Conclusion and clinical relevance

This study details the first isolation of T. abortisuis from goats. The genotypic findings of this isolate will serve as a baseline description for any similar future studies.

Role of biofilms in antimicrobial resistance of the bacterial bovine respiratory disease complex

An increase in chronic, non-responsive bovine respiratory disease (BRD) infections in North American feedlot cattle is observed each fall, a time when cattle are administered multiple antimicrobial treatments for BRD. A number of factors are responsible for BRD antimicrobial treatment failure, with formation of biofilms possibly being one. It is widely accepted that biofilms play a role in chronic infections in humans and it has been hypothesized that they are the default lifestyle of most bacteria. However, research on bacterial biofilms associated with livestock is scarce and significant knowledge gaps exist in our understanding of their role in AMR of the bacterial BRD complex. The four main bacterial species of the BRD complex, Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, and Mycoplasma bovis are able to form biofilms in vitro and there is evidence that at least H. somni retains this ability in vivo. However, there is a need to elucidate whether their biofilm-forming ability contributes to pathogenicity and antimicrobial treatment failure of BRD. Overall, a better understanding of the possible role of BRD bacterial biofilms in clinical disease and AMR could assist in the prevention and management of respiratory infections in feedlot cattle. We review and discuss the current knowledge of BRD bacteria biofilm biology, study methodologies, and their possible relationship to AMR.

Bilateral cavernous sinus and ophthalmic vein thrombosis secondary to Trueperella pyogenes rhinosinusitis

Ophthalmic vein thrombosis is a severe clinical entity with proptosis, eyelid swelling, orbital pain and reduction of visual acuity; its incidence is rare with 3-4 cases /million /year. Clinical manifestations result from venous congestion caused by septic (orbital cellulitis) or aseptic aetiologies (coagulopathies, trauma) and in some cases it could be associated with cavernous sinus thrombosis. In this paper, we describe a case report unique in the literature, of bilateral cavernous sinus and ophthalmic veins thrombosis due to both septic and aseptic causes characterized by unilateral sphenoid sinusitis sustained by Trueperella pyogenes infection. Trueperella pyogenes is an opportunistic animal pathogen, and its infections occur in both domestic and wild animals worldwide but are rare in humans; this is the first instance of human infection in the head and neck with an unknown hypercoagulable state.

Case report: Omphalitis caused by Trueperella pyogenes infection in a Korean indigenous calf

Omphalitis, commonly caused by opportunistic bacteria has been significantly associated with morbidity and mortality in neonatal calves. Trueperella pyogenes is a commensal and opportunistic pathogen that can cause suppurative infection in farm animals. Our case involved a 10-day-old female Korean indigenous calf that presented with umbilical enlargement accompanied by a greenish-yellow purulent discharge and right forelimb lameness. The calf was diagnosed with failure of passive transfer at 24 h of age. Physical examination found hypothermia (38.1°C), tachycardia (110 beats/min), tachypnea (47 cycles/min), and open mouth breathing. Ultrasonography revealed hyperechoic pus in the 9th and 10th right intercostals, for which a liver abscess due to omphalophlebitis was suspected. After 3 days, the calf died. T. pyogenes was detected in the umbilical cord, lung, liver, kidney, intestine, mesenteric lymph node, urinary bladder, and bladder ligament. All genes related to the virulent factors (i.e., plo, cbpA, fimA, fimC, fimG, nanH, and nanP) were also identified, with plo and fimA being associated with pathogenicity. A final diagnosis of omphalitis was established based on the identification of virulent T. pyogenes and umbilical cord dilatation on ultrasonography. Antimicrobial susceptibility tests showed that the isolated T. pyogenes was susceptible to amoxicillin, ceftiofur, florfenicol, enrofloxacin, ofloxacin, and ciprofloxacin, suggesting the suitability of these antibiotics for treating T. pyogenes-induced omphalitis. Hence, accurate and rapid diagnosis of the involved bacteria and antimicrobial susceptibility patterns can help guide therapeutic decisions. Our case provides useful information that could aid large animal clinicians in the diagnosis and treatment of T. pyogenes-induced omphalitis.

Molecular Characterization of Resistance and Virulence Factors of Trueperella pyogenes Isolated from Clinical Bovine Mastitis Cases in China

Purpose

The present study was designed to investigate the resistance determinants and virulence factors of 45 Trueperella pyogenes isolates from clinical bovine mastitis in Hexi Corridor of Gansu, China.

Methods

Minimum inhibitory concentrations (MICs) was tested by E-test method. Gene of antimicrobial resistance, virulence integrase and integron gene cassettes were determined by PCR and DNA sequencing.

Results

The T. pyogenes isolates exhibited high resistance to streptomycin (88.9%) and tetracycline (64.4%), followed by erythromycin (15.6%) and gentamicin (13.3%). Resistance to streptomycin was most commonly encoded by aadA9 (88.9%); and to tetracycline, by tetW (64.4%). Importantly, all streptomycin-resistant isolates carried aadA9 alone or in combination with aadA1, aadA11 and strA-strB. Similarly, all tetracycline-resistant isolates harbored tetW alone or in combination with tetA33. Meanwhile, ermX was detected in 13.3% isolates, only one erythromycin-resistant isolate was not identified for this gene. Moreover, all T. pyogenes isolates carried class 1 integrons, and 17.8% of them contained gene cassettes, including arrays aadA1-aadB (4.4%), aad A24-dfrA1-ORF1 (2.2%) and aadA1 (2.2%). Furthermore, all tested isolates harbored virulent genes plo and fimA, followed by fimC (88.9%), fimE (86.6%) nanP (75.6%), nanH (40.0%), cbpA (35.6%) and fimG (6.7%).

Conclusion

To our knowledge, this is the first report of integron gene cassettes of T. pyogenes isolates from bovine mastitis cases in China. These findings are useful for developing the prevention and the virulence factors of T. pyogenes could be promising candidates for vaccine antigens for bovine mastitis caused by T. pyogenes in China.

Emerging Approaches for Mitigating Biofilm-Formation-Associated Infections in Farm, Wild, and Companion Animals

The importance of addressing the problem of biofilms in farm, wild, and companion animals lies in their pervasive impact on animal health and welfare. Biofilms, as resilient communities of microorganisms, pose a persistent challenge in causing infections and complicating treatment strategies. Recognizing and understanding the importance of mitigating biofilm formation is critical to ensuring the welfare of animals in a variety of settings, from farms to the wild and companion animals. Effectively addressing this issue not only improves the overall health of individual animals, but also contributes to the broader goals of sustainable agriculture, wildlife conservation, and responsible pet ownership. This review examines the current understanding of biofilm formation in animal diseases and elucidates the complex processes involved. Recognizing the limitations of traditional antibiotic treatments, mechanisms of resistance associated with biofilms are explored. The focus is on alternative therapeutic strategies to control biofilm, with illuminating case studies providing valuable context and practical insights. In conclusion, the review highlights the importance of exploring emerging approaches to mitigate biofilm formation in animals. It consolidates existing knowledge, highlights gaps in understanding, and encourages further research to address this critical facet of animal health. The comprehensive perspective provided by this review serves as a foundation for future investigations and interventions to improve the management of biofilm-associated infections in diverse animal populations.

Phenotypic Characteristics, Antimicrobial Susceptibility and Virulence Genotype Features of Trueperella pyogenes Associated with Endometritis of Dairy Cows

Trueperella pyogenes can cause various infections in the organs and tissues of different livestock (including pigs, cows, goats, and sheep), including mastitis, endometritis, pneumonia, or abscesses. Moreover, diseases induced by T. pyogenes cause significant economic losses in animal husbandry. In recent large-scale investigations, T. pyogenes has been identified as one of the main pathogens causing endometritis in lactating cows. However, the main treatment for the above-mentioned diseases is still currently antibiotic therapy. Understanding the impact of endometritis associated with T. pyogenes on the fertility of cows can help optimize antibiotic treatment for uterine diseases, thereby strategically concentrating the use of antimicrobials on the most severe cases. Therefore, it is particularly important to continuously monitor the prevalence of T. pyogenes and test its drug resistance. This study compared the uterine microbiota of healthy cows and endometritis cows in different cattle farms, investigated the prevalence of T. pyogenes, evaluated the genetic characteristics and population structure of isolated strains, and determined the virulence genes and drug resistance characteristics of T. pyogenes. An amount of 186 dairy cows were involved in this study and 23 T. pyogenes strains were isolated and identified from the uterine lavage fluid of dairy cows with or without endometritis.

Exploring oxidative stress, immunological and metabolic biomarkers in dairy cows with postpartum pyometra

Pyometra is a prevalent and severe infectious disease that affects the reproductive systems of cattle worldwide. This study's main goal was to investigate the biomarkers for oxidative stress (OS), adiponectin, leptin and neopterin (NPT) in cows suffering from postpartum pyometra. The study also aimed to determine which bacteria were most commonly implicated in the development of the disease. A total of 74 cows with pyometra were examined and compared to a control group of healthy cows (n = 20). In comparison to the healthy control and post-treatment groups, the pyometra group showed higher mean values of leptin, adiponectin and malondialdehyde (MDA). In contrast, the glutathione (GSH) and superoxide dismutase (SOD) mean values were lower in the pyometra group as compared to the post-treatment and control groups. NPT levels in the post-treatment groups were lower than those in cows with pyometra but comparable to the healthy control group (p > .05). When compared to the other biomarkers, NPT, leptin and adiponectin showed higher sensitivity and specificity in identifying pyometra cases (AUC ≥0.99). The predominant bacterial isolates from the ptomtra-affected cows consisted of Escherichia coli (N = 29; 39.2%), Arcanobacterium pyogenes (N = 27; 36.5%) and Fusobacterium necrophorum (N = 13; 17.6%). Mixed infection was determined in nine samples (12.2%). Conclusively, OS, adiponectin, leptin and NPT play crucial roles in comprehending the development of postpartum pyometra in cows and have the potential to serve as biomarkers for the disease.

Metagenomic sequencing sheds light on microbes putatively associated with pneumonia-related fatalities of white-tailed deer (Odocoileus virginianus)

With emerging infectious disease outbreaks in human, domestic and wild animal populations on the rise, improvements in pathogen characterization and surveillance are paramount for the protection of human and animal health, as well as the conservation of ecologically and economically important wildlife. Genomics offers a range of suitable tools to meet these goals, with metagenomic sequencing facilitating the characterization of whole microbial communities associated with emerging and endemic disease outbreaks. Here, we use metagenomic sequencing in a case-control study to identify microbes in lung tissue associated with newly observed pneumonia-related fatalities in 34 white-tailed deer (Odocoileus virginianus) in Wisconsin, USA. We identified 20 bacterial species that occurred in more than a single individual. Of these, only Clostridium novyi was found to substantially differ (in number of detections) between case and control sample groups; however, this difference was not statistically significant. We also detected several bacterial species associated with pneumonia and/or other diseases in ruminants (Mycoplasma ovipneumoniae, Trueperella pyogenes, Pasteurella multocida, Anaplasma phagocytophilum, Fusobacterium necrophorum); however, these species did not substantially differ between case and control sample groups. On average, we detected a larger number of bacterial species in case samples than controls, supporting the potential role of polymicrobial infections in this system. Importantly, we did not detect DNA of viruses or fungi, suggesting that they are not significantly associated with pneumonia in this system. Together, these results highlight the utility of metagenomic sequencing for identifying disease-associated microbes. This preliminary list of microbes will help inform future research on pneumonia-associated fatalities of white-tailed deer.

The bacterial and archaeal communities of flies, manure, lagoons, and troughs at a working dairy

Background

Fundamental investigations into the location, load, and persistence of microbes, whether beneficial or detrimental, are scarce. Many questions about the retention and survival of microbes on various surfaces, as well as the load necessary for spread, exist. To answer these questions, we must know more about where to find various microbes and in what concentrations, the composition of the microbial communities, and the extent of dissemination between various elements. This study investigated the diversity, composition, and relative abundance of the communities associated with manure, lagoons, troughs, house flies, and stable flies present at a dairy, implementing two different free-stall management systems: flow-through and cross-vent. Shotgun metagenomics at the community level was used to compare the microbiomes within the dairy, allowing confident interpretation at the species level.

Results

The results showed that there were significant difference in microbial composition between not only each of the dairy elements but also management styles. The primary exceptions were the microbiomes of the house fly and the stable fly. Their compositions heavily overlapped with one another, but interestingly, not with the other components sampled. Additionally, both species of flies carried more pathogens than the other elements of the dairy, indicating that they may not share these organisms with the other components, or that the environments offered by the other components are unsatisfactory for the survival of some pathogens..

Conclusion

The lack of overlapping pathogen profiles suggests a lack of transfer from flies to other dairy elements. Dairy health data, showing a low incidence of disease, suggests minimal sharing of bacteria by the flies at a level required for infection, given the health program of this dairy. While flies did carry a multitude of pathogenic bacteria, the mere presence of the bacteria associated with the flies did not necessarily translate into high risk leading to morbidity and mortality at this dairy. Thus, using flies as the sole sentinel of dairy health may not be appropriate for all bacterial pathogens or dairies.

Metagenomic profiling of viral and microbial communities from the pox lesions of lumpy skin disease virus and sheeppox virus-infected hosts

Introduction

It has been recognized that capripoxvirus infections have a strong cutaneous tropism with the manifestation of skin lesions in the form of nodules and scabs in the respective hosts, followed by necrosis and sloughing off. Considering that the skin microbiota is a complex community of commensal bacteria, fungi and viruses that are influenced by infections leading to pathological states, there is no evidence on how the skin microbiome is affected during capripoxvirus pathogenesis.

Methods

In this study, shotgun metagenomic sequencing was used to investigate the microbiome in pox lesions from hosts infected with lumpy skin disease virus and sheep pox virus.

Results

The analysis revealed a high degree of variability in bacterial community structures across affected skin samples, indicating the importance of specific commensal microorganisms colonizing individual hosts. The most common and abundant bacteria found in scab samples were Fusobacterium necrophorum, Streptococcus dysgalactiae, Helcococcus ovis and Trueperella pyogenes, irrespective of host. Bacterial reads belonging to the genera Moraxella, Mannheimia, Corynebacterium, Staphylococcus and Micrococcus were identified.

Discussion

This study is the first to investigate capripox virus-associated changes in the skin microbiome using whole-genome metagenomic profiling. The findings will provide a basis for further investigation into capripoxvirus pathogenesis. In addition, this study highlights the challenge of selecting an optimal bioinformatics approach for the analysis of metagenomic data in clinical and veterinary practice. For example, direct classification of reads using a kmer-based algorithm resulted in a significant number of systematic false positives, which may be attributed to the peculiarities of the algorithm and database selection. On the contrary, the process of de novo assembly requires a large number of target reads from the symbiotic microbial community. In this work, the obtained sequencing data were processed by three different approaches, including direct classification of reads based on k-mers, mapping of reads to a marker gene database, and de novo assembly and binning of metagenomic contigs. The advantages and disadvantages of these techniques and their practicality in veterinary settings are discussed in relation to the results obtained.

First Report of Caseous Lymphadenitis by Corynebacterium pseudotubercolosis and Pulmonary Verminosis in a Roe Deer (Capreolus capreolus Linnaeus, 1758) in Italy

Caseous lymphadenitis is a chronic debilitating disease typical of small ruminants, but it is also noted in several other domestic and wild species. In this report, we present the first documented case in Italy of pseudotuberculosis in a roe deer (Capreolus capreolus, Linnaeus 1758) found dead in the mountains of Forlì-Cesena province, Emilia Romagna region. The carcass underwent necropsy according to standard protocols, revealing generalized lymphadenopathy and severe apostematous pneumonia with multifocal and encapsulated abscesses. Corynebacterium pseudotuberculosis was isolated from the lung parenchyma, lymph nodes and abscesses. Additionally, severe parasitic bronchopneumonia of the caudal lobes and gastrointestinal strongyle infestation were detected. To our knowledge, this is the first documented case of CLA referable to C. pseudotubercolosis in a roe deer in Italy.

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.

Fecal and vaginal microbiota of vaccinated and non-vaccinated pregnant elk challenged with Brucella abortus

Introduction

Brucella abortus is the causative agent of brucellosis in cattle and in humans, resulting in economic losses in the agricultural sector and representing a major threat to public health. Elk populations in the American Northwest are reservoirs for this bacterium and transmit the agent to domestic cattle herds. One potential strategy to mitigate the transmission of brucellosis by elk is vaccination of elk populations against B. abortus; however, elk appear to be immunologically distinct from cattle in their responses to current vaccination strategies. The differences in host response to B. abortus between cattle and elk could be attributed to differences between the cattle and elk innate and adaptive immune responses. Because species-specific interactions between the host microbiome and the immune system are also known to affect immunity, we sought to investigate interactions between the elk microbiome and B. abortus infection and vaccination.

Methods

We analyzed the fecal and vaginal microbial communities of B. abortus-vaccinated and unvaccinated elk which were challenged with B. abortus during the periparturient period.

Results

We observed that the elk fecal and vaginal microbiota are similar to those of other ruminants, and these microbial communities were affected both by time of sampling and by vaccination status. Notably, we observed that taxa representing ruminant reproductive tract pathogens tended to increase in abundance in the elk vaginal microbiome following parturition. Furthermore, many of these taxa differed significantly in abundance depending on vaccination status, indicating that vaccination against B. abortus affects the elk vaginal microbiota with potential implications for animal reproductive health.

Discussion

This study is the first to analyze the vaginal microbiota of any species of the genus Cervus and is also the first to assess the effects of B. abortus vaccination and challenge on the vaginal microbiome.

Infectious sporadic bovine abortions: retrospective analysis

Infectious sporadic abortions in cattle are mainly caused by opportunistic bacteria and fungi usually present in environmental or gastrointestinal and reproductive microbiota of healthy animals. A retrospective analysis was carried out to evaluate the main opportunistic microorganisms involved in bovine abortions recorded at INTA Balcarce (Argentina) from 1997 to 2023, accounting for 2.2% of the total diagnosed etiologies of bovine abortion. The opportunistic agents identified as the cause of abortion in 29 fetuses were bacteria (90%) and fungi (10%). Escherichia coli (n = 8), Trueperella pyogenes (n = 5), and Histophilus somni (n = 4) were the bacterial species most often identified as causing infectious abortions, whereas Aspergillus spp. (n = 3) was implicated in all fungal abortions identified. Pure culture of bacteria or fungus was achieved from abomasal content and/or lung essential. Main microscopic findings were bronchopneumonia, myo- and epicarditis, meningitis, and portal hepatitis. Herein, we highlight the importance of detecting potential infectious bacteria in cultures to improve etiological diagnosis of bovine abortions associated with compatible microscopic findings to confirm the etiology.

Uterine microbial ecology and disease in cattle: A review

Due to the critical contribution of the uterine-associated microbiota in reproductive health, physiology, and performance, culture-independent methods have been increasingly employed to unravel key aspects of microbial ecology in the uterus of cattle. Nowadays, we know that bacterial diversity is crucial to maintain uterine health, however, there is still no consensus on the exact composition of a healthy uterine microbiota (or eubiosis). Generally, loss of bacterial diversity (or dysbiosis) contributes to the development of uterine infections, associated with increased relative abundances of Bacteroides, Fusobacterium, Trueperella, and Porphyromonas. Uterine infections are highly prevalent and gravely influence the profitability of cattle operations, animal welfare, and public health. Thus, understanding the dynamics of uterine microbial ecology is essential to develop effective strategies focused on preventing and mitigating the adverse effects of uterine dysbiosis as well as assisting in the process of restoring the core, healthy uterine microbiota. The aim of this review is to summarize research conducted in the microbial ecology of bovine uteri. We discuss the origin of the uterine microflora of healthy cows and the factors influencing its composition. In addition, we review the biology of specific pathogens that are known to increase in abundance during the occurrence of uterine disease. Lastly, we provide an overview of the bacterial biofilm in the bovine endometrium, and we briefly summarize the rationale for the use of probiotics to prevent uterine disease in cattle.

Trueperella pyogenes endocarditis in a Swiss farmer: a case report and review of the literature

BACKGROUND

Trueperella pyogenes (T. pyogenes) is a bacterium that colonizes the skin and mucosal surfaces of various domestic and wild animals. It rarely leads to infections in humans, with only a few descriptions available in the literature.

CASE PRESENTATION

A 71-year-old Swiss farmer with a history of recurring basal cell carcinoma and metastasized pancreatic neuroendocrine tumor presented with signs of sepsis after a three-day history of general weakness, malaise and fever. Clinical and echocardiographic findings, as well as persistent bacteremia were consistent with mitral valve endocarditis caused by T. pyogenes. The patient's condition gradually improved under antibiotic treatment with piperacillin/tazobactam (empiric therapy of sepsis), and later penicillin G based on resistance testing. He was discharged after 13 days and continued outpatient antibiotic therapy with ceftriaxone, resulting in a total antibiotic treatment duration of six weeks. This is the first literature review of T. pyogenes endocarditis in humans. Among nine cases of T. pyogenes endocarditis, three patients had documented contact with farm animals and five had an underlying condition that compromised the immune system. While antibiotic resistance of T. pyogenes is an emerging concern, susceptibility to beta-lactam antibiotics seems to persist. The mortality of T. pyogenes endocarditis described in the literature was high, with 66% of patients not surviving the disease.

CONCLUSIONS

T. pyogenes is a rare causative organism of infectious endocarditis in humans and descriptions are mainly restricted to case reports. In our review of the literature, we found that both an impaired immune system and contact with farm animals might be risk factors. Growth of T. pyogenes in blood cultures is unlikely to be missed during routine analysis, as it shows marked beta-hemolysis on blood agar culture plates, which generally leads to further characterization of the bacteria. Susceptibility to penicillin, ceftriaxone, and macrolides seems to be retained and the reported mortality in the few patients with T. pyogenes endocarditis is high.

Postmortem diagnoses and factors influencing diagnoses in captive white-tailed deer in Wisconsin, 2009-2021

There have been significant changes to Wisconsin agriculture since ~2010, one of which is the growth of commercial farming of white-tailed deer (WTD; Odocoileus virginianus). These high-density populations may lead to the emergence of previously unrecognized or under-recognized disease trends. I evaluated archived pathology records at the Wisconsin Veterinary Diagnostic Laboratory (WVDL) from 2009-2021 for captive WTD postmortem cases and included records from 277 WTD cases. Diagnoses were found in 81.9% of cases, with an average of 1.3 diagnoses per animal. Submissions with a clinical history of respiratory disease were 7.0 times more likely to have a diagnosis than the average case. Fawns were 1.9 times more likely to have a diagnosis. The most common diagnoses were bronchopneumonia and enteritis and/or enterocolitis (both 16.2% of total diagnoses). The most common isolates from bronchopneumonia cases were Pasteurella multocida, Bibersteinia trehalosi, and Trueperella pyogenes. The pathogens identified most often in enteritis and/or enterocolitis cases were rotavirus, Clostridium perfringens, and Escherichia coli. The most common non-infectious diagnoses were poor nutritional status or inanition, hepatic lipidosis, and selenium and/or vitamin E deficiency. Focusing on testing for pathogens in fawns and in cervid respiratory disease complex submissions may be recommended for laboratories expanding their WTD testing.

Preparation and evaluation of recombinant pyolysin, fimbriae E and HtaA based protein vaccines against Trueperella pyogenes

Trueperella pyogenes (T. pyogenes) could cause zoonotic disease in various mammals, resulting in significant economic losses. Due to the lack of effective vaccine and the emergence of bacterial resistance, there is a big need for new and improved vaccines. In this study, the non-hemolytic pyolysin mutant (PLOW497F), fimbriae E (FimE) and a truncated cell wall protein (HtaA-2) were selected to generate single or multivalent protein vaccines and their efficacies against lethal T. pyogenes challenge were evaluated in a mouse model. The results showed that the levels of specific antibody were significantly higher than the PBS control group after the booster vaccination. Compared to PBS treated mice, vaccinated mice had upregulated expressions of the inflammatory cytokine genes after the first vaccination. There was a downward trend thereafter, but return to the similar or even higher levels after challenge. Furthermore, co-immunization with rFimE or rHtaA-2 could significantly enhance the anti-hemolysis antibodies induced by rPLOW497F. The supplement of rHtaA-2 induced higher agglutinating antibodies compared with single administration with rPLOW497F or rFimE. Apart from these, the pathological lesions of lung were alleviated in rHtaA-2, rPLOW497F or their combinations immunized mice. Notably, immunization with rPLOW497F, rHtaA-2, combinations of rPLOW497F and rHtaA-2 or rHtaA-2 and rFimE completely protected mice from challenge, whereas the PBS immunized mice could not survive past 1 day post challenge. Thus, PLOW497F and HtaA-2 might be useful in developing efficient vaccines to prevent T. pyogenes infection.

Novel macrolide-lincosamide-streptogramin B resistance gene erm(56) in Trueperella pyogenes

Whole-genome sequence analysis of a macrolide, lincosamide, streptogramin B (MLSB)-resistant Trueperella pyogenes from a dog revealed a new 23S ribosomal RNA methylase gene erm(56). Expression of the cloned erm(56) confers resistance to MLSB in T. pyogenes and Escherichia coli. The erm(56) gene was flanked by two IS6100 integrated on the chromosome next to a sul1-containing class 1 integron. GenBank query revealed additional erm(56)-containing elements in another T. pyogenes and in Rothia nasimurium from livestock. IMPORTANCE A novel 23S ribosomal RNA methylase gene erm(56) flanked by insertion sequence IS6100 was identified in a Trueperella pyogenes isolated from the abscess of a dog and was also present in another T. pyogenes and in Rothia nasimurium from livestock. It was shown to confer resistance to macrolide, lincosamide, streptogramin B antibiotics in T. pyogenes and E. coli, indicating functionality in both Gram-positive and Gram-negative bacteria. The detection of erm(56) on different elements in unrelated bacteria from different animal sources and geographical origins suggests that it has been independently acquired and likely selected by the use of antibiotics in animals.

The role of Actinomyces spp. and related organisms in cervicofacial infections: Pathomechanism, diagnosis and therapeutic aspects

Members of the Actinomyces genus and Actinomyces-like organisms (ALOs; namely Actinotignum, Arcanobacterium, Schaalia and Varibaculum) are Gram-positive, non-spore-forming rods that are commensal members of the human oral cavity, gastrointestinal tract, female genital tract and skin microbiota. Cervicofacial actinomycosis or "lumpy jaw syndrome" - the chronic, suppurative granulomatous disease caused by Actinomyces spp. And ALOs - is characterized by an initially slow and unspecific disease-presentation, which often mimics other pathologies, followed by the formation of painful abscesses and severe tissue destruction. Actinomycosis has been described as a rare disease, however, reliable epidemiological data are lacking. In addition, there is increasing awareness regarding the role of Actinomyces spp. in the development of osteoradionecrosis and medication-related osteonecrosis of the jaw. The aim of this narrative review is to succinctly summarize the current advances regarding the microbiological, clinical, diagnostic and therapeutic aspects of cervicofacial actinomycosis, in addition to the roles of Actinomyces species and ALOs as members of the oral microbiota and in dental biofilm, in other dental infections (caries, root canal infection, periapical infection, periodontitis) and osteonecrosis of the jaw, in the context of recent taxonomic changes affecting the genus. Our paper aims to be a blueprint for dentists, other physicians, microbiologists and researchers regarding the multifaceted field of cervicofacial actinomycosis.

Diseases of Iberian ibex (Capra pyrenaica)

Iberian ibex (Capra pyrenaica) is an ecologically and economically relevant medium-sized emblematic mountain ungulate. Diseases participate in the population dynamics of the species as a regulating agent, but can also threaten the conservation and viability of vulnerable population units. Moreover, Iberian ibex can also be a carrier or even a reservoir of pathogens shared with domestic animals and/or humans, being therefore a concern for livestock and public health. The objective of this review is to compile the currently available knowledge on (1) diseases of Iberian ibex, presented according to their relevance on the health and demography of free-ranging populations; (2) diseases subjected to heath surveillance plans; (3) other diseases reported in the species; and (4) diseases with particular relevance in captive Iberian ibex populations. The systematic review of all the information on diseases affecting the species unveils unpublished reports, scientific communications in meetings, and scientific articles, allowing the first comprehensive compilation of Iberian ibex diseases. This review identifies the gaps in knowledge regarding pathogenesis, immune response, diagnostic methods, treatment, and management of diseases in Iberian ibex, providing a base for future research. Moreover, this challenges wildlife and livestock disease and wildlife population managers to assess the priorities and policies currently implemented in Iberian ibex health surveillance and monitoring and disease management.

Feeding hempseed cake alters the bovine gut, respiratory and reproductive microbiota

A growing number of studies have investigated the feasibility of utilizing hemp by-products as livestock feedstuffs; however, their impact on livestock microbiomes remains unexplored. Here, we evaluated the effects of feeding hempseed cake on the gastrointestinal, respiratory, and reproductive microbiota in beef heifers. Angus-crossbred heifers (19-months old, initial body weight = 494 ± 10 kg [SE]) were fed a corn-based finishing diet containing 20% hempseed cake as a substitute for 20% corn dried distillers' grains with solubles (DM basis; Control; n = 16/group) for 111 days until slaughter. Ruminal fluid and deep nasopharyngeal swabs (days 0, 7, 42, 70 and 98), and vaginal and uterine swabs (at slaughter) were collected, and the microbiota assessed using 16S rRNA gene sequencing. Diet affected the community structure of the ruminal (d 7-98; 0.06 ≤ R² ≤ 0.12; P < 0.05), nasopharyngeal (d 98; R² = 0.18; P < 0.001), and vaginal (R² = 0.06; P < 0.01) microbiota. Heifers fed hempseed cake had increased microbial diversity in the rumen, reduced microbial richness in the vagina, and greater microbial diversity and richness in the uterus. In addition to the distinct microbial communities in the rumen, nasopharynx, vagina and uterus, we identified 28 core taxa that were shared (≥ 60% of all samples) across these sampling locations. Feeding hempseed cake appeared to alter the bovine gut, respiratory and reproductive microbiota. Our results suggest that future research aiming to evaluate the use of hemp by-products in livestock diet should consider their impact on animal microbiome and microbiome mediated animal health and reproductive efficiency. Our findings also highlight the need for research evaluating the impact of hemp-associated food and personal care products on the human microbiome.

Current Situation of Bacterial Infections and Antimicrobial Resistance Profiles in Pet Rabbits in Spain

Research on antimicrobial resistance (AMR) in pet rabbits is very scarce. The aim of this study was to provide an overview of the current state of AMR in rabbits attended to in veterinary clinics distributed in Spain. Records of 3596 microbiological results of clinical cases submitted from 2010 to 2021 were analyzed. Staphylococcus spp. (15.8%), Pseudomonas spp. (12.7%), Pasteurella spp. (10%), Bordetella spp. (9.6%) and Streptococcus spp. (6.8%) were the most frequently diagnosed agents. Enterobacteriaceae, principally Escherichia coli, Klebsiella pneumoniae and Enterobacter cloacae, accounted for about 18% of the cases and showed the highest proportion of multi-drug resistance (MDR) isolates, with 48%, 57.5% and 36% of MDR, respectively. Regarding the antimicrobial susceptibility testing for a number of antimicrobial categories/families, the largest proportion of isolates showing resistance to a median of five antimicrobial categories was observed in P. aeruginosa, Stenotrophomonas maltophilia and Burkolderia spp. In contrast, infections caused by Staphylococcus, Streptococcus spp. and Pasteurella multocida were highly sensitive to conventional antimicrobials authorized for veterinary use (categories D and C). The emergence of AMR major nosocomial opportunistic pathogens such as P. aeruginosa, S. maltophilia and K. pneumoniae in pet rabbits can represent a serious public health challenge. Consequently, collaboration between veterinarians and human health professionals is crucial in the fight against antimicrobial resistance, to optimize, rationalize and prudently use antimicrobial therapies in domestic animals and humans.

Comparative phylogenomics of Trueperella pyogenes reveals host-based distinction of strains

Trueperella pyogenes, an opportunistic pathogen causes various ailments in different animals. Different strains from different animals have distinct characters phenotypically and genotypically. Hence understanding the strains in a particular geographical location helps in framing the preventive measures. Comparative genomics of all the available T. pyogenes genome in the NCBI was conducted to understand the relatedness among strains. Whole genome phylogeny showed host associated clustering of strains recovered from swine lungs. Core genome phylogeny also showed host associated clustering mimicking whole genome phylogeny results. MLST analysis showed that there was higher diversity among cattle strains. Multidimensional scaling revealed five swine clusters, two cattle and buffalo clusters. Pangenome analysis also showed that T. pyogenes had an open genome with 57.09% accessory genome. Host specific genes were identified by pangenome analysis, and (R)-citramalate synthase was specific for swine strains of Asian origin. Host specifc genes identified by pangenome analysis can be exploited for developing a molecular assay to specifically identify the strains. The study shows that MLST having higher discriminatory power can be used as an epidemiological tool for strain discrimination of T. pyogenes.

Construction of live-attenuated Trueperella pyogenes by antibiotic treatment and sequential passage: methods for vaccine development

Trueperella pyogenes (T. pyogenes) is a zoonotic pathogen that is cause a variety of pyogenic diseases in animals. The complex pathogenicity and various virulence factors are important challenges to produce an effective vaccine. According to previous trials, inactivated whole-cell bacteria or recombinant vaccines were unsuccessful in preventing disease. Thus, this study aims to introduce a new vaccine candidate based on a live-attenuated platform. For this purpose, first T. pyogenes was subjected to sequential passage (SP) and antibiotic treatment (AT) to lose their pathogenicity. Second, Plo and fimA expressions as virulence genes were evaluated by qPCR and then mice were challenged with bacteria from SP and AT culture by intraperitoneal route. Compared to the control group (T. pyogenes-wild type), plo and fimA gene expressions were downregulated and vaccinated mice have a normal spleen appearance in contrast to the control group. In addition, there was no significant difference between bacterial count from spleen, liver, heart and peritoneal fluid in vaccinated mice and the control group. In conclusion, this study introduces a new T. pyogenes vaccine candidate based on a live-attenuated strategy that mimics natural infection without pathogenicity for further investigation on vaccines against T. pyogenes infections.

Viability and function dynamics of circulating versus endometrial polymorphonuclear leukocytes in postpartum dairy cows with subclinical or clinical endometritis

We aimed to compare the viability of circulating polymorphonuclear leukocyte (cPMN) and endometrial PMN (ePMN) and their function dynamics in postpartum dairy cows with subclinical (SCE) or clinical endometritis (CE). To do so, blood samples from 38 Holstein cows were collected at -7, 9, 21, and 36 d relative to calving, and endometrial cytology samples from 32 Holstein cows were harvested at 9, 21, and 36 d postpartum. Uterine health status was assessed at 36 d postpartum, and cows were classified as healthy (absence of abnormal vaginal discharge and ≤5% ePMN), SCE (absence of abnormal vaginal discharge and >5% ePMN), or CE (mucopurulent or purulent vaginal discharge and >5% ePMN). Viability (viable, apoptotic, and necrotic) and function parameters phagocytosis (PC), oxidative burst, and intracellular proteolytic degradation were evaluated for cPMN via flow cytometry. For ePMN, only viability and PC were evaluated. The association of cPMN and ePMN viability and functional parameters with reproductive tract health classification were fitted in mixed linear regression models, accounting for repeated measures, sampling day, and interactions of reproductive tract status and day. Cows with CE had a lower proportion of cPMN viability (84.5 ± 2.1%; least squares means ± standard error) and a higher proportion of apoptosis (14.4 ± 2.0%) than healthy (92.4 ± 1.3 and 6.7 ± 1.3%, respectively) or SCE (95.3 ± 2.4 and 3.8 ± 2.3%, respectively) at 9 d postpartum. Interestingly, cPMN intracellular proteolytic degradation was lower [6.2 ± 0.1 median fluorescence intensity (MFI)] in SCE compared with healthy (6.7 ± 0.08 MFI) or CE (6.8 ± 0.1 MFI) at d 9 postpartum. No other differences in cPMN function were found among experimental groups. The proportion of necrotic ePMN was higher for healthy (49.6 ± 5.1%) than SCE (27.4 ± 7.3%) and CE (27.7 ± 7.3%) cows at 36 d postpartum. Also, at 36 d postpartum, the proportion of ePMN performing PC was higher in CE (47.0 ± 8.6%) than in healthy (18.4 ± 7.6%) cows, but did not differ from SCE cows (25.9 ± 8.7%). Results of the present study suggest that cPMN viability and function at 9 d postpartum are associated with the development of uterine disease. Furthermore, ePMN at 36 d postpartum are mostly necrotic in healthy cows but viable and functional in cows with CE, probably due to active uterine inflammation. Remarkably, ePMN in cows with SCE at 36 d postpartum are also mostly viable but seem to display a numerically lower proportion of PC compared with ePMN in CE cows.

Involvement of the E3 ubiquitin ligase Cblb in host defense and evaluation of transcriptome during Trueperella pyogenes infection

Trueperella pyogenes (T. pyogenes) is a versatile and ingenious bacterium that causes severe suppurative injuries in lots of economically important ruminants. The underlying pathogenesis of T. pyogenes infection remains poorly understood. In the current study, we performed transcriptome sequencing of mouse blood tissue infected with T. pyogenes. A total of 36.73 G clean data were collected, and 136 differentially expressed genes were obtained in the infection group compared to the control group. In addition, we found that the E3 ubiquitin ligase Cblb exhibited significant upregulation in the infection groups compared to the control group. Mechanistically, T. pyogenes infection markedly enhanced the expression of Cblb and regulated the host defense response. Inhibiting Cblb expression with Cblb siRNA impaired the inflammatory response and reduced the effect of phagocytosis in RAW264.7 murine macrophages. Intriguingly, overexpression of Cblb induced a strong inflammatory response and enhanced phagocytosis against T. pyogenes infection in macrophages. More importantly, the overexpression of Cblb significantly reduced the bacterial load and protected mice from the T. pyogenes infections. Therefore, our findings reveal that Cblb is a novel and potential regulator in response to T. pyogenes infection and shed new light on the development of promising treatments against T. pyogenes-related diseases.

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

Trueperella pyogenes is an opportunistic animal pathogen mainly associated with various suppurative infections in wild and domestic animals. Limited studies have investigated the pathogenesis of diseases caused by this pathogen. The main objective of the current study was to investigate the prevalence, phenotypic properties, virulence genotypes, antimicrobial susceptibility and genetic characterization of T. pyogenes isolated from abscess lesions in different tissues of on-farm dairy cattle. The study was performed on 150 postpartum cattle with clinical abscess symptoms on 22 farms around Tehran, Iran. Classical and disk diffusion methods are used for phenotypic characterization and antibiotic susceptibility. Detection of virulence factor encoding genes and genomic characterization of the isolates also are carried out by conventional PCR and BOX-PCR assays, respectively. Sixty-eight T. pyogenes strains (45.3%) were isolated, 12 were identified as pure cultures and the other 56 strains were isolated from mixed cultures. Seven distinct biotypes were identified among the T. pyogenes isolates. The isolates were mostly resistance to trimethoprim-sulfamethoxazole (70.6%), erythromycin (36.7%), tetracycline (26.5%) and tylosin (23.5%) antibiotics. Also, the genes plo, nanH, nanP and fimA were detected in all isolates. Forty-two isolates (61.7%) carried all virulence factor genes detected in this study. Three isolates only carried plo, nanH, nanP and fimA genes were identified as the least frequent genotype. All sixty-eight isolates and the reference strain were categorized into seven main clusters (A-G). A strong association was observed between virulence factor encoding genes, pathogenicity and biochemical biotypes in some specific clonal relationships.

Comparative Genome Analysis of 19 Trueperella pyogenes Strains Originating from Different Animal Species Reveal a Genetically Diverse Open Pan-Genome

Trueperella pyogenes is a Gram-positive opportunistic pathogen that causes severe cases of mastitis, metritis, and pneumonia in a wide range of animals, resulting in significant economic losses. Although little is known about the virulence factors involved in the disease pathogenesis, a comprehensive comparative genome analysis of T. pyogenes genomes has not been performed till date. Hence, present investigation was carried out to characterize and compare 19 T. pyogenes genomes originating in different geographical origins including the draftgenome of the first Indian origin strain T. pyogenes Bu5. Additionally, candidate virulence determinants that could be crucial for their pathogenesis were also detected and analyzed by using various bioinformatics tools. The pan-genome calculations revealed an open pan-genome of T. pyogenes. In addition, an inventory of virulence related genes, 190 genomic islands, 31 prophage sequences, and 40 antibiotic resistance genes that could play a significant role in organism's pathogenicity were detected. The core-genome based phylogeny of T. pyogenes demonstrates a polyphyletic, host-associated group with a high degree of genomic diversity. The identified core-genome can be further used for screening of drug and vaccine targets. The investigation has provided unique insights into pan-genome, virulome, mobiliome, and resistome of T. pyogenes genomes and laid the foundation for future investigations.

Safe Sialidase Production by the Saprophyte Oerskovia paurometabola: Gene Sequence and Enzyme Purification

Sialidase preparations are applied in structural and functional studies on sialoglycans, in the production of sialylated therapeutic proteins and synthetic substrates for use in biochemical research, etc. They are obtained mainly from pathogenic microorganisms; therefore, the demand for apathogenic producers of sialidase is of exceptional importance for the safe production of this enzyme. Here, we report for the first time the presence of a sialidase gene and enzyme in the saprophytic actinomycete Oerskovia paurometabola strain O129. An electrophoretically pure, glycosylated enzyme with a molecular weight of 70 kDa was obtained after a two-step chromatographic procedure using DEAE cellulose and Q-sepharose. The biochemical characterization showed that the enzyme is extracellular, inductive, and able to cleave α(2→3,6,8) linked sialic acids with preference for α(2→3) bonds. The enzyme production was strongly induced by glycomacropeptide (GMP) from milk whey, as well as by sialic acid. Investigation of the deduced amino acid sequence revealed that the protein molecule has the typical six-bladed β-propeller structure and contains all features of bacterial sialidases, i.e., an YRIP motif, five Asp-boxes, and the conserved amino acids in the active site. The presence of an unusual signal peptide of 40 amino acids was predicted. The sialidase-producing O. paurometabola O129 showed high and constant enzyme production. Together with its saprophytic nature, this makes it a reliable producer with high potential for industrial application.

The endoplasmic reticulum stress-mediated unfolded protein response protects against infection of goat endometrial epithelial cells by Trueperella pyogenes via autophagy

Trueperella pyogenes is an important bacterial pathogen of a wide range of domestic and wild animals. Autophagy plays a key role in eliminating T. pyogenes in a process that is dependent on mechanistic target of rapamycin (mTOR). The endoplasmic reticulum (ER) stress response also is critical for autophagy regulation. However, the relationship between ER stress and T. pyogenes is uncharacterized and the intracellular survival mechanisms of T. pyogenes have not been investigated adequately. In this study, we show that T. pyogenes invades goat endometrial epithelial cells (gEECs). Meanwhile, we observed that GRP78 was upregulated significantly, and that unfolded protein response (UPR) also were activated after infection. Additionally, treatment with activators and inhibitors of ER stress downregulated and upregulated, respectively, intracellular survival of T. pyogenes. Blocking the three arms of the UPR pathway separately enhanced T. pyogenes survival and inflammatory reaction to different levels. We also show that LC3-labeled autophagosomes formed around the invading T. pyogenes and that autolysosome-like vesicles were visible in gEECs using transmission electron microscopy. Moreover, tunicamycin did not inhibit the intracellular survival of T. pyogenes under conditions in which autophagy was blocked. Finally, severe challenge with T. pyogenes induced host cell apoptosis which also may indicate a role for ER stress in the infection response. In summary, we demonstrate here that ER stress and UPR are novel modulators of autophagy that inhibit T. pyogenes intracellular survival in gEECs, which has the potential to be developed as an effective therapeutic target in T. pyogenes infectious disease.

Comparative genomics of Trueperella pyogenes available in the genome database reveals multidrug resistance genomic islands

OBJECTIVE

An opportunistic pathogen, Trueperella pyogenes can infect cattle, buffalo, pig, goat, cat, dog, forest musk deer, etc., affecting various organs. The aim of this study was to identify the multidrug resistance genomic islands of T. pyogenes genomes available in NCBI database and also in the recently isolated strain TN_CUL_2020.

METHODS

The strain TN_CUL_2020 isolated from swine lung abscess was sequenced by Illumina platform, and all the available T. pyogenes genome in NCBI database was retrieved for the comparative analysis. The ABRicate searches was used to identify antimicrobial resistance genes, and genomic islands (GIs) were predicted using IslandViewer 4.

RESULTS

The strains SH01, SH02, and TP1 were predicted with maximum number of drug resistance genes. Genomic islands identified had multidrug resistance genes along with the class I integron and/or IS6100 elements in SH01, SH02, TP1. Composite transposons of IS6100 were noted in T2849, T4479, and TP3 intercalating tet(33) resistance genes. Several strains were predicted with phage elements, type IV secretion system, the toxin-antitoxin system in the GIs.

CONCLUSION

Swine strains SH01, SH02 were predicted with multidrug resistance genes along with class I integrons. The presence of class I integrons, insertional elements, type IV secretion system, toxin-antitoxin system, and phage elements may aid in the horizontal transfer of antimicrobial resistance genes.

Effects of Luteolin on Biofilm of Trueperella pyogenes and Its Therapeutic Effect on Rat Endometritis

Trueperella pyogenes is an opportunistic pathogen that causes suppurative infections in animals. The development of new anti-biofilm drugs will improve the current treatment status for controlling T. pyogenes infections in the animal husbandry industry. Luteolin is a naturally derived flavonoid compound with antibacterial properties. In this study, the effects and the mechanism of luteolin on T. pyogenes biofilm were analyzed and explored. The MBIC and MBEC of luteolin on T. pyogenes were 156 μg/mL and 312 μg/mL, respectively. The anti-biofilm effects of luteolin were also observed by a confocal laser microscope and scanning electron microscope. The results indicated that 312 μg/mL of luteolin could disperse large pieces of biofilm into small clusters after 8 h of treatment. According to the real-time quantitative PCR detection results, luteolin could significantly inhibit the relative expression of the biofilm-associated genes luxS, plo, rbsB and lsrB. In addition, the in vivo anti-biofilm activity of luteolin against T. pyogenes was studied using a rat endometritis model established by glacial acetic acid stimulation and T. pyogenes intrauterine infusion. Our study showed that luteolin could significantly reduce the symptoms of rat endometritis. These data may provide new opinions on the clinical treatment of luteolin and other flavonoid compounds on T. pyogenes biofilm-associated infections.

Whole-Genome Sequences of Antibiotic-Resistant Trueperella pyogenes Isolates from Surgical Site Infections in Dairy Cows in Switzerland

The complete genome sequence of four Trueperella pyogenes isolated from cattle surgical site infections in Switzerland was determined using hybrid assembly of Oxford Nanopore and Illumina reads. Genes conferring resistance to tetracyclines [ tet (W)], sulfonamides ( sul1 ), chloramphenicol ( cmx ), streptomycin/spectinomycin ( aadA1 ), and quaternary ammonium compounds ( qacE Δ 1 ) were identified on different chromosomal elements.

Mammary Adenoma Associated with Chronic Mastitis in a Wild Boar (Sus Scrofa)

Mammary gland tumor is rare and only a few cases have been reported in wild animals. Moreover, most etiologies of the known cases in veterinary medicine are related to age, diet, obesity, and excessive sex hormones in domestic animals while few etiologies are reported in wild animals. An unknown-aged female wild boar was presented to the Department of Veterinary Pathology, Kyungpook National University with a well-demarcated, and firm-to-elastic mammary gland mass. The cut-surface of the mass was pink-reddish, and homogeneous. Microscopically, the mass was mainly composed of well-differentiated neoplastic glandular epithelial cells characterized by a single-layer, columnar to cuboidal shapes, and small and central nuclei and nucleoli. Any evidence of invasiveness or metastases of the neoplastic cells were not observed. Interestingly, infiltration of chronic inflammatory cells such as plasma cells and macrophages was observed along with a large quantity of gram-negative and positive bacterial colonies in the mammary glands. Moreover, accompanied fibrosis of stroma was observed, as well. Based on the gross and microscopic findings, the present case was diagnosed as mammary simple adenoma caused by chronic mastitis progressing to fibrotic condition. To the authors’ knowledge, this is the first study describing the histopathological aspects of mammary gland tumors associated with chronic mastitis accompanied by fibrosis in wild animals.

Molecular Basis for Luteolin as a Natural TatD DNase Inhibitor in Trueperella pyogenes

TatD960 and TatD825 are DNases that contribute to biofilm formation and virulence in Trueperella pyogenes (T. pyogenes). Luteolin is a natural flavonoid commonly found in plants that exhibits antimicrobial capacity. Our study aims to investigate the effects of luteolin on TatD DNases as a natural inhibitor. In this research, the expression of tatD genes and TatD proteins in T. pyogenes treated with luteolin was detected, and then the effect of luteolin on the hydrolysis of DNA by TatD DNases was analyzed using agarose gel electrophoresis. Moreover, the interactions between luteolin and TatD DNases were tested using surface plasmon resonance (SPR) assays and molecular docking analysis. After 1/2 MIC luteolin treatment, the transcription of tatD genes and expression of TatD proteins appeared to be reduced in 80–90% of T. pyogenes (n = 20). The gel assay revealed that luteolin can inhibit the activity of TatD DNases. The SPR assay showed that the KD values of luteolin to TatD960 and TatD825 were 6.268 × 10⁻⁶ M and 5.654 × 10⁻⁶ M, respectively. We found through molecular docking that hydrogen bonding is predominant in the interaction of luteolin and TatD DNases. Our data indicate that luteolin inhibited the ability of TatD DNases by decreasing their binding to DNA. The current study provides an insight into the development of luteolin as a DNase inhibitor in preventing biofilm formation and virulence in T. pyogenes.

Prevalence and Genetic Diversity of Trueperella pyogenes Isolated from Infections in European Bison (Bison bonasus)

Simple Summary

In the European bison, Trueperella pyogenes is associated with different suppurative infections of mainly the urogenital tract or with abscesses in various tissues. Our research showed that in the studied population of European bison in Poland, the prevalence of T. pyogenes infections is relatively high. The significant genetic diversity of isolated strains was observed. However, in a few cases, the same RAPD profile was obtained for strains isolated from individuals living in the same area. Our study indicated that different virulence factors are related to the pathogenicity of this bacterium. The results obtained in this study provide valuable data about the prevalence, pathogenicity and genetic diversity of T. pyogenes in the European bison. Thus, it improves the knowledge on treatment for the European bison’s health and proves the importance of continuous monitoring for the protection of these wild ruminants.

Abstract

Trueperella pyogenes is a Gram-positive bacterium causing purulent infections in many animal species, including the European bison. However, the data about the virulence and genetic relationships of T. pyogenes strains isolated from these wild ruminants are strongly limited. The aim of this study was to investigate the prevalence of T. pyogenes infections in the European bison, and to evaluate the genetic diversity of isolates from these animals. In the time span of 10 years, 328 European bison from 16 different locations were examined. The standard bacteriological methods were used for T. pyogenes isolation and identification from clinical specimens obtained from urogenital tract infections and abscesses of different locations. The presence of genes encoding known virulence factors was investigated by PCR, and the genetic diversity of T. pyogenes strains was examined with the RAPD-PCR method. The prevalence of T. pyogenes infections was 14.6%, and the pathogen was isolated from both female (47.9% of isolates) and male (52.1% of isolates) European bison. It should be highlighted that a considerable number of strains were isolated from the prepuce and penis infections. Therefore, the role of T. pyogenes in the pathogenesis of balanoposthitis should be seriously perceived. A total of 39 T. pyogenes strains were subjected to genetic characterization. All studied strains carried the plo gene, while the nanH (25.6%), nanP (23.1%), cbpA (7.7%), fimA (97.4%), fimC (69.2%), fimE (92.3%) and fimG (15.4%) genes were present with a variable frequency among the tested strains. The virulence genotype plo/fimA/fimC/fimE was dominant. RAPD-PCR typing showed a high level of genetic diversity among European bison T. pyogenes strains, and a total of 31 different RAPD profiles were distinguished. In a few cases, the same RAPD profile was found in strains obtained from animals living in the same area. This study provided the first data about the prevalence and genetic relationships of T. pyogenes in the Polish population of European bison. However, further epidemiological investigations are needed to understand the routes of transmission and dissemination of the pathogen in these wild animals.

Causes of Sow Mortality and Risks to Post-Mortem Findings in a Brazilian Intensive Swine Production System

The present study was conducted to investigate the risk factors for post-mortem findings and causes of sow mortality. A post-mortem examination and microbiological investigation were conducted on 123 sows from a breeding herd with 15,000 dams. The mortality of spontaneous death in sows occurred mostly in the peripartum period (53%; p < 0.05). The spontaneous deaths were associated with heart failures, hemorrhagic and perforating gastric ulcers, and liver torsion, while in the euthanized sows, the post-mortem findings were associated with locomotor disorders. A higher body condition score (BCS ≥ 3.5) increased (p < 0.05) heart failure on the post-mortem examination. The excessive use of manual obstetric interventions increased sow deaths resulting from cervix/uterus ruptures and increased the odds of death (p < 0.05) due to metritis. Sow mortality had a multifactorial etiology. Infections were polymicrobial. The main microbial agents identified from a septic lesion in locomotor, genitourinary, and respiratory systems were Trueperella pyogenes, Escherichia coli, and Actinobacillus pleuropneumoniae, respectively. In conclusion, sow mortality involved multiple risk factors and several bacterial agents. These results indicate that better management practices can reduce sow mortality in swine production and increase sow welfare.

Corpse decay of wild animals leads to the divergent succession of nrfA-type microbial communities

Animal carcasses introduce large amounts of nitrates and ammonium into the soil ecosystem. Some of this ammonium is transformed from nitrite through the nrfA-type microbial community. However, it is unclear how nrfA-type microorganisms respond to the decomposition of corpses. This study applied high-throughput sequencing to characterize the ecological succession of nrfA-type microbial communities in grassland soil. Our results showed that Cyclobacterium and Trueperella were the predominant genera for nrfA-type communities in soil with a decomposing corpse (experimental group), while Cyclobacterium and Archangium were dominant in soil without a corpse (control group). The alpha diversity indexes and the resistance and resilience indexes of the microbial communities initially increased and then decreased during decomposition. Compared with the control group, nrfA-encoding community structure in the experimental group gradually became divergent with succession and temporal turnover accelerated. Network analysis revealed that the microbial communities of the experimental group had more complex interactions than those of the control groups. Moreover, the bacterial community assembly in the experimental group was governed by stochastic processes, and the communities of the experimental group had a weaker dispersal capacity than those of the control group. Our results reveal the succession patterns of the nrfA-type microbial communities during degradation of wild animal corpses, which can offer references for demonstrating the ecological mechanism underlying the changes in the nrfA-type microbial community during carcass decay. KEY POINTS: • Corpse decay accelerates the temporal turnover of the nrfA-type community in soil. • Corpse decay changes the ecological succession of the nrfA-type community in soil. • Corpse decay leads to a complex co-occurrence pattern of the nrfA-type community in soil.

Heterologous Prime-Boost Immunization with DNA Vaccine and Modified Recombinant Proteins Enhances Immune Response against Trueperella pyogenes in Mice

Trueperella pyogenes (T. pyogenes) is a crucial opportunistic pathogen normally causing mastitis, abscesses and pneumonia in economically important ruminants. Although only one commercial vaccine of T. pyogenes is currently obtainable, its immunoprotective effect is limited. Pyolysin (PLO) is the most predominant virulence factor highly expressed in T. pyogenes and is an excellent target for the development of novel vaccines against T. pyogenes. In this study, we designed a heterologous prime-boost vaccination scheme combining a DNA vaccine pVAX1-PLO and a subunit vaccine His-PLO to maximize host responses in mice. Humoral and cellular immune responses and protective effects were evaluated in mice to compare the immunogenicity induced by different immunization schemes. Compared to the PBS-control group, in vivo immunization results showed that better immune responses of mice immunized with the pVAX1-PLO plasmids and His-PLO proteins were induced. The residual bacterial burdens from the liver and peritoneal fluid were remarkably decreased in the immunized mice compared with the PBS group. Notably, the heterologous prime-boost vaccination groups significantly enhanced host humoral and cellular immune responses and protected mice from different virulent T. pyogenes strains infection. Conclusively, this study provides a favorable strategy for the further development of next-generation vaccines against T. pyogenes infections.

RAPD-PCR-Based Fingerprinting Method as a Tool for Epidemiological Analysis of Trueperella pyogenes Infections

In this study, a Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) method for genetic typing of Trueperella pyogenes, an opportunistic bacterial pathogen, was designed. The method optimization was performed for 37 clinical T. pyogenes strains isolated from various infections in different animal species. Optimal conditions for reliable and reproducible DNA fingerprinting were determined according to the modified Taguchi method. The developed method was assessed regarding its typeability, reproducibility, and discriminatory power using the Hunter’s and Gatsons’ index of discrimination. A high degree of genetic diversity was shown between the studied strains, which represented 31 genotypes. The generated RAPD profiles were relatively complex and simultaneously easy to interpret due to the wide size range of amplicons. The discriminatory index of the designed method was sufficiently high; thus, only strains epidemiologically related displayed identical RAPD genotypes. In conclusion, the DNA fingerprinting of T. pyogenes by the developed RAPD-PCR method is a reliable typing tool that may allow a better understanding of the epidemiology as well as pathogenesis of infections caused by this pathogen.

Pyolysin of Trueperella pyogenes Induces Pyroptosis and IL-1β Release in Murine Macrophages Through Potassium/NLRP3/Caspase-1/Gasdermin D Pathway

Trueperella pyogenes (T. pyogenes) is a commensal and an opportunistic pathogen of animals. This organism can cause inflammatory diseases, such as pneumonia, mastitis and endometritis in hosts. However, the molecular basis for the pro-inflammatory properties of this organism is still largely unknown. In the current study, using murine macrophages as model, the ability of T. pyogenes to induce pyroptosis was first determined. Then, pyolysin (PLO), a cholesterol-dependent cytolysin secreted by T. pyogenes, was found to be closely related to T. pyogenes-induced pyroptosis. Next, our work showed that PLO can form pores in the cell membrane, leading to the efflux of potassium (K⁺), NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome-mediated caspase-1 activation, and gasdermin D (GSDMD) cleavage. Inhibition of the K⁺/NLRP3/caspase-1/GSDMD pathway abolished T. pyogenes and PLO-induced IL-1β release. Taken together, these results indicate T. pyogenes-induced inflammation is related to PLO-induced pyroptosis and IL-1β release. Our work shed light on the pathogenesis of T. pyogenes and the interaction between T. pyogenes and hosts' immune system.

Pathogenic and Endosymbiotic Bacteria and Their Associated Antibiotic Resistance Biomarkers in Amblyomma and Hyalomma Ticks Infesting Nguni Cattle (Bos spp.)

Deciphering the interactions between ticks and their microbiome is key to revealing new insights on tick biology and pathogen transmission. However, knowledge on tick-borne microbiome diversity and their contribution to drug resistance is scarce in sub–Saharan Africa (SSA), despite endemism of ticks. In this study, high-throughput 16S rRNA amplicon sequencing and PICRUSt predictive function profiling were used to characterize the bacterial community structure and associated antibiotic resistance markers in Amblyomma variegatum, A. hebraeum, and Hyalomma truncatum ticks infesting Nguni cattle (Bos spp.). Twenty-one (seven families and fourteen genera) potentially pathogenic and endosymbiotic bacterial taxa were differentially enriched in two tick genera. In H. truncatum ticks, a higher abundance of Corynebacterium (35.6%), Porphyromonas (14.4%), Anaerococcus (11.1%), Trueperella (3.7%), and Helcococcus (4.7%) was detected. However, Rickettsia (38.6%), Escherichia (7%), and Coxiellaceae (2%) were the major differentially abundant taxa in A. variegatum and A. hebraeum. Further, an abundance of 50 distinct antibiotic resistance biomarkers relating to multidrug resistance (MDR) efflux pumps, drug detoxification enzymes, ribosomal protection proteins, and secretion systems, were inferred in the microbiome. This study provides theoretical insights on the microbiome and associated antibiotic resistance markers, important for the design of effective therapeutic and control decisions for tick-borne diseases in the SSA region.