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Frontiers in Microbiology 2023is a widespread, highly infectious bacterial pathogen that causes respiratory disease in swine and increases the severity of respiratory infections caused by other...
is a widespread, highly infectious bacterial pathogen that causes respiratory disease in swine and increases the severity of respiratory infections caused by other viral or bacterial pathogens. However, the impact of infection on the swine respiratory microbiota has not been thoroughly investigated. Here, we aim to assess the influence of infection on the community structure and abundance of members of the swine nasal microbiota. To do so, the nasal microbiota of a non-infected control group and a group infected with (BB group) were characterized prior to strain KM22 challenge (day 0) and on selected days in the weeks following challenge (days 1, 3, 7, 10, 14, 21, 36, and 42). was cultured from nasal samples of the BB group to assess nasal colonization. The results showed that colonization did not persistently affect the nasal bacterial diversity of either of the treatment groups (alpha diversity). However, the bacterial community structures (beta diversity) of the two treatment groups significantly diverged on day 7 when peak colonization levels of were detected. This divergence continued through the last sampling time point. In addition, (unclassified), , and (unclassified) showed increased abundances in the BB group relative to the control group at various time points. This study revealed that colonization can disturb the upper respiratory tract microbiota, and further research is warranted to assess how these disturbances can impact susceptibility to secondary infections by other respiratory pathogens.
PubMed: 37840723
DOI: 10.3389/fmicb.2023.1260465 -
Frontiers in Microbiology 2023Actinobacillus pleuropneumoniae is an important respiratory pathogen, which can cause porcine contagious pleuropneumonia and lead to great economic losses to worldwide...
INTRODUCTION
Actinobacillus pleuropneumoniae is an important respiratory pathogen, which can cause porcine contagious pleuropneumonia and lead to great economic losses to worldwide swine industry. High potassium is an adverse environment for bacteria, which is not conducive to providing turgor pressure for cell growth and division. Two-component system CpxAR is an important regulatory system of bacteria in response to environmental changes, which is involved in a variety of biological activities, such as antibiotic resistance, periplasmic protein folding, peptidoglycan metabolism and so on.
METHODS
However, little is known about the role of CpxAR in high potassium stress in . Here, we showed that CpxAR is critical for cell division of under high potassium (K) stress.
RESULTS
qRT-PCR analysis found that CpxAR positively regulated the cell division genes In addition, we also demonstrated that CpxR-P could directly bind the promoter region of the cell division gene by EMSA.
DISCUSSION
In conclusion, our results described a mechanism where CpxAR adjusts survival under high-K stress by upregulating the expression of the cell division proteins FtsE and FtsX. These findings are the first to directly demonstrate CpxAR-mediated high-K tolerance, and to investigate the detailed molecular mechanism.
PubMed: 37822748
DOI: 10.3389/fmicb.2023.1259935 -
Frontiers in Pharmacology 2023Formulating a therapeutic strategy that can effectively combat concurrent infections of () and () can be challenging. This study aimed to 1) establish minimum...
Formulating a therapeutic strategy that can effectively combat concurrent infections of () and () can be challenging. This study aimed to 1) establish minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), time kill curve, and post-antibiotic effect (PAE) of tylosin against and pig isolates and employ the MIC data for the development of epidemiological cutoff (ECOFF) values; 2) estimate the pharmacokinetics (PKs) of tylosin following its intramuscular (IM) administration (20 mg/kg) in healthy and infected pigs; and 3) establish a PK-pharmacodynamic (PD) integrated model and predict optimal dosing regimens and PK/PD cutoff values for tylosin in healthy and infected pigs. The MIC of tylosin against both 89 and 363 isolates of and strains spread widely, ranging from 1 to 256 μg/mL and from 0.5 to 128 μg/mL, respectively. According to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) ECOFFinder analysis ECOFF value (≤64 µg/mL), 97.75% (87 strains) of the isolates were wild-type, whereas with the same ECOFF value (≤64 µg/mL), 99.72% (363 strains) of the isolates were considered wild-type to tylosin. Area under the concentration time curve (AUC), T, and C values were significantly greater in healthy pigs than those in infected pigs (13.33 h × μg/mL, 1.99 h, and 5.79 μg/mL vs. 10.46 h × μg/mL, 1.83 h, and 3.59 μg/mL, respectively) ( < 0.05). In healthy pigs, AUC/MIC values for the bacteriostatic activity were 0.98 and 1.10 h; for the bactericidal activity, AUC/MIC values were 1.97 and 1.99 h for and , respectively. In infected pigs, AUC/MIC values for the bacteriostatic activity were 1.03 and 1.12 h; for bactericidal activity, AUC/MIC values were 2.54 and 2.36 h for and , respectively. Monte Carlo simulation lead to a 2 μg/mL calculated PK/PD cutoff. Managing co-infections can present challenges, as it often demands the administration of multiple antibiotics to address diverse pathogens. However, using tylosin, which effectively targets both and in pigs, may enhance the control of bacterial burden. By employing an optimized dosage of 11.94-15.37 mg/kg and 25.17-27.79 mg/kg of tylosin can result in achieving bacteriostatic and bactericidal effects in 90% of co-infected pigs.
PubMed: 37808183
DOI: 10.3389/fphar.2023.1258403 -
The Canadian Veterinary Journal = La... Oct 2023This study aims to identify the most common causes of equine perinatal loss up to 7 d of age in Canada.
OBJECTIVE
This study aims to identify the most common causes of equine perinatal loss up to 7 d of age in Canada.
ANIMAL
Equine.
PROCEDURE
Necropsy reports from 360 equine perinatal loss cases were acquired from provincial veterinary diagnostic labs across Canada. Each case was classified into a basic cause (noninfectious, infectious, or unidentified) of perinatal loss, then further classified into primary and secondary categories for analysis.
RESULTS
Of the basic causes of perinatal loss, noninfectious causes were the most common. Bacterial causes, such as septicemia, were the most common primary diagnosis overall. was the most commonly identified bacterial species.
CONCLUSION
This study showed similar results to those of studies conducted in other countries, including having similar etiologic agents identified. The high prevalence of thyroid hyperplasia identified in this study is notable and was not reported in other, similar retrospective studies, despite being reported in locations other than Canada.
CLINICAL RELEVANCE
Perinatal loss can have important economic consequences for horse breeders; thus, identification of the most common causes is of interest to both veterinarians and breeders.
Topics: Pregnancy; Female; Horses; Animals; Humans; Horse Diseases; Retrospective Studies; Canada; Veterinarians
PubMed: 37780478
DOI: No ID Found -
Bioengineering (Basel, Switzerland) Sep 2023Plaque biofilms play critical roles in the development of dental caries. Mechanical plaque control methods are considered to be most effective for plaque removal, such...
Plaque biofilms play critical roles in the development of dental caries. Mechanical plaque control methods are considered to be most effective for plaque removal, such as brushing teeth or using flosser. Recently, water flosser has been paid much attention. Here, we tested the ability of a water flosser to remove the adhered sucrose and the dental plaque biofilms formed by , , and . We found that the residual sucrose concentration was 3.54 mg/mL in the control group, 1.75 mg/mL in the syringe group (simulating the ordinary mouthwash), and 0 mg/mL in water flosser group. In addition, the residual bacterial concentration was 3.6 × 10 CFU/mL in the control group, 1.6 × 10 CFU/mL in the syringe group, and only 5.5 × 10 CFU/mL in the water flosser group. In summary, water flosser is effective for cleaning the teeth, which may have significant potential in preventing dental caries and maintaining oral health.
PubMed: 37760162
DOI: 10.3390/bioengineering10091061 -
BMC Veterinary Research Sep 2023The early development of intestinal microbiota plays a fundamental role in host health and development. To investigate the difference in the intestinal microbial...
BACKGROUND
The early development of intestinal microbiota plays a fundamental role in host health and development. To investigate the difference in the intestinal microbial composition between Lantang and Landrace newborn piglets, we amplified and sequenced the V3-V4 region of 16 S rRNA gene in jejunal microbiota of Lantang and landrace newborn.
RESULTS
The findings revealed that the dominant phyla in the jejunum of Lantang piglets were Firmicutes, Actinobacteria and Bacteroidetes, while the dominant phyla of Landrace is Proteobacteria and Fusobacteria. Specifically, Corynebacterium_1, Lactobacillus, Rothia, Granulicatella, Corynebacteriales_unclassified, Corynebacterium, Globicatella and Actinomycetales_unclassified were found to be the dominant genera of Lantang group, while Clostridium_sensu_stricto_1, Escherichia-Shigella, Actinobacillus and Bifidobacterium were the dominant genera of Landrace. Based on the functional prediction of bacteria, we found that bacterial communities from Lantang samples had a significantly greater abundance pathways of fatty acid synthesis, protein synthesis, DNA replication, recombination, repair and material transport across membranes, while the carrier protein of pathogenic bacteria was more abundant in Landrace samples.
CONCLUSIONS
Overall, there was a tremendous difference in the early intestinal flora composition between Landang and Landrace piglets, which was related to the breed characteristics and may be one of the reasons affecting the growth characteristics. However, more further extensive studies should be included to reveal the underlying relationship between early intestinal flora composition in different breeds and pig growth characteristics.
Topics: Animals; Swine; Animals, Newborn; Gastrointestinal Microbiome; Plant Breeding; Bacteria; Jejunum; RNA, Ribosomal, 16S
PubMed: 37759242
DOI: 10.1186/s12917-023-03642-z -
Journal of Global Antimicrobial... Dec 2023The aim of this study was to characterize the floR-carrying plasmids originating from Glaesserella parasuis and Actinobacillus indolicus isolated from pigs with...
OBJECTIVES
The aim of this study was to characterize the floR-carrying plasmids originating from Glaesserella parasuis and Actinobacillus indolicus isolated from pigs with respiratory disease in China.
METHODS
A total of 125 G. parasuis and 28 A. indolicus strains collected between 2009 and 2022 were screened for florfenicol resistance. Characterization of floR-positive isolates and plasmids were determined by antimicrobial susceptibility testing, serotyping, multilocus sequence typing (MLST), conjugation and transformation assays, whole-genome sequencing (WGS), and phylogenetic analysis.
RESULTS
One A. indolicus and six G. parasuis were identified as positive for floR. The six G. parasuis were assigned to four different serovars, including serovars 6, 7, 9, and unknown. In addition to strain XP11, six floR genes were located on plasmids. The six floR-bearing plasmids could be transformed into Pasteurella multocida and divided into two different types, including ∼5000 bp and ∼6000 bp plasmids. The ∼5000 bp plasmids consisting of rep, lysR, mobB, and floR genes, exhibited high similarity among Pasteurellaceae bacteria. Furthermore, the ∼6000 bp plasmids, consisting of rep, lysR, mobC, mobA/L, and floR genes, showed high similarity between G. parasuis and Actinobacillus Spp. Notably, WGS results showed that the floR modules of the two types of plasmids could be transferred and integrated into the diverse Pasteurellaceae- origined plasmids.
CONCLUSION
This study firstly reported the characterization of floR-carrying plasmids from A. indolicus and a non-virulent serovar of G. parasuis in pigs in China and elucidated the transmission mechanism of the floR resistance gene among the Pasteurellaceae family.
Topics: Animals; Swine; Anti-Bacterial Agents; Multilocus Sequence Typing; Phylogeny; Plasmids; Actinobacillus
PubMed: 37726088
DOI: 10.1016/j.jgar.2023.09.009 -
Veterinary Research Sep 2023Due to the increase in bacterial resistance, improving the anti-infectious immunity of the host is rapidly becoming a new strategy for the prevention and treatment of...
Due to the increase in bacterial resistance, improving the anti-infectious immunity of the host is rapidly becoming a new strategy for the prevention and treatment of bacterial pneumonia. However, the specific lung immune responses and key immune cell subsets involved in bacterial infection are obscure. Actinobacillus pleuropneumoniae (APP) can cause porcine pleuropneumonia, a highly contagious respiratory disease that has caused severe economic losses in the swine industry. Here, using high-dimensional mass cytometry, the major immune cell repertoire in the lungs of mice with APP infection was profiled. Various phenotypically distinct neutrophil subsets and Ly-6C inflammatory monocytes/macrophages accumulated post-infection. Moreover, a linear differentiation trajectory from inactivated to activated to apoptotic neutrophils corresponded with the stages of uninfected, onset, and recovery of APP infection. CD14 neutrophils, which mainly increased in number during the recovery stage of infection, were revealed to have a stronger ability to produce cytokines, especially IL-10 and IL-21, than their CD14 counterparts. Importantly, MHC-II neutrophils with antigen-presenting cell features were identified, and their numbers increased in the lung after APP infection. Similar results were further confirmed in the lungs of piglets infected with APP and Klebsiella pneumoniae infection by using a single-cell RNA-seq technique. Additionally, a correlation analysis between cluster composition and the infection process yielded a dynamic and temporally associated immune landscape where key immune clusters, including previously unrecognized ones, marked various stages of infection. Thus, these results reveal the characteristics of key neutrophil clusters and provide a detailed understanding of the immune response to bacterial pneumonia.
Topics: Animals; Mice; Swine; Neutrophils; Actinobacillus pleuropneumoniae; Pneumonia; Pleuropneumonia; Mycoplasma Infections; Actinobacillus Infections; Ascomycota; Lung; Swine Diseases
PubMed: 37705063
DOI: 10.1186/s13567-023-01207-4 -
JACS Au Aug 2023The soluble N-glycosyltransferase from (ApNGT) can establish an N-glycosidic bond at the asparagine residue in the Asn-Xaa-Ser/Thr consensus sequon and is one of the...
The soluble N-glycosyltransferase from (ApNGT) can establish an N-glycosidic bond at the asparagine residue in the Asn-Xaa-Ser/Thr consensus sequon and is one of the most promising tools for N-glycoprotein production. Here, by integrating computational and experimental strategies, we revealed the molecular mechanism of the substrate recognition and following catalysis of ApNGT. These findings allowed us to pinpoint a key structural motif (DVYM) in ApNGT responsible for the peptide substrate recognition. Moreover, Y222 and H371 of ApNGT were found to participate in activating the acceptor Asn. The constructed models were supported by further crystallographic studies and the functional roles of the identified residues were validated by measuring the glycosylation activity of various mutants against a library of synthetic peptides. Intriguingly, with particular mutants, site-selective N-glycosylation of canonical or noncanonical sequons within natural polypeptides from the SARS-CoV-2 spike protein could be achieved, which were used to investigate the biological roles of the N-glycosylation in membrane fusion during virus entry. Our study thus provides in-depth molecular mechanisms underlying the substrate recognition and catalysis for ApNGT, leading to the synthesis of previously unknown chemically defined N-glycoproteins for exploring the biological importance of the N-glycosylation at a specific site.
PubMed: 37654596
DOI: 10.1021/jacsau.3c00214 -
Antibiotics (Basel, Switzerland) Aug 2023Porcine respiratory disease complex (PRDC) has been a major animal health, welfare, and economic problem in Hungary; therefore, great emphasis should be put on both the...
Porcine respiratory disease complex (PRDC) has been a major animal health, welfare, and economic problem in Hungary; therefore, great emphasis should be put on both the prevention and control of this complex disease. As antibacterial agents are effective tools for control, antibiotic susceptibility testing is indispensable for the proper implementation of antibacterial therapy and to prevent the spread of resistance. The best method for this is to determine the minimum inhibitory concentration (MIC) by the broth microdilution method. In our study, we measured the MIC values of 164 , 65 , and 118 isolates isolated from clinical cases against the following antibacterial agents: amoxicillin, ceftiofur, cefquinome, oxytetracycline, doxycycline, tylosin, tilmicosin, tylvalosin, tulathromycin, lincomycin, tiamulin, florfenicol, colistin, enrofloxacin, and sulfamethoxazole-trimethoprim. Outstanding efficacy against isolates was observed with ceftiofur (100%) and tulathromycin (100%), while high levels of resistance were observed against cefquinome (92.7%) and sulfamethoxazole-trimethoprim (90.8%). Ceftiofur (98.4%), enrofloxacin (100%), florfenicol (100%), and tulathromycin (100%) were found to be highly effective against isolates, while 100% resistance was detected against the sulfamethoxazole-trimethoprim combination. For the isolates, only ceftiofur (100%) was not found to be resistant, while the highest rate of resistance was observed against the sulfamethoxazole-trimethoprim combination (94.3%). An increasing number of studies report multi-resistant strains of all three pathogens, making their monitoring a high priority for animal and public health.
PubMed: 37627719
DOI: 10.3390/antibiotics12081298