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Microorganisms May 2024Pradofloxacin is the newest of the veterinary fluoroquinolones to be approved for use in animals-initially companion animals and most recently food animals. It has a...
Comparative In Vitro Killing by Pradofloxacin in Comparison to Ceftiofur, Enrofloxacin, Florfenicol, Marbofloxacin, Tildipirosin, Tilmicosin and Tulathromycin against Bovine Respiratory Bacterial Pathogens.
Pradofloxacin is the newest of the veterinary fluoroquinolones to be approved for use in animals-initially companion animals and most recently food animals. It has a broad spectrum of in vitro activity, working actively against Gram-positive/negative, atypical and some anaerobic microorganisms. It simultaneously targets DNA gyrase (topoisomerase type II) and topoisomerase type IV, suggesting a lower propensity to select for antimicrobial resistance. The purpose of this study was to determine the rate and extent of bacterial killing by pradofloxacin against bovine strains of and , in comparison with several other agents (ceftiofur, enrofloxacin, florfenicol, marbofloxacin, tildipirosin, tilmicosin and tulathromycin) using four clinically relevant drug concentrations: minimum inhibitory and mutant prevention drug concentration, maximum serum and maximum tissue drug concentrations. At the maximum serum and tissue drug concentrations, pradofloxacin killed 99.99% of cells following 5 min of drug exposure (versus growth to 76% kill rate for the other agents) and 94.1-98.6% of following 60-120 min of drug exposure (versus growth to 98.6% kill rate for the other agents). Statistically significant differences in kill rates were seen between the various drugs tested depending on drug concentration and time of sampling after drug exposure.
PubMed: 38792823
DOI: 10.3390/microorganisms12050996 -
Pathogens (Basel, Switzerland) May 2024Pradofloxacin-a dual-targeting fluoroquinolone-is the most recent approved for use in food animals. Minimum inhibitory and mutant prevention concentration values were...
Pradofloxacin-a dual-targeting fluoroquinolone-is the most recent approved for use in food animals. Minimum inhibitory and mutant prevention concentration values were determined for pradofloxacin, ceftiofur, enrofloxacin, florfenicol, marbofloxacin, tildipirosin, tilmicosin, and tulathromycin. For strains, MIC values were ≤0.016/≤0.016/≤0.016 and MPC values were 0.031/0.063/0.063; for strains, the MIC values ≤0.016/≤0.016/0.031 and MPC ≤ 0.016/0.031/0.063 for pradofloxacin. The pradofloxacin C/MIC and C/MPC values for and strains, respectively, were 212.5 and 53.9 and 212.5 and 109.7. Similarly, AUC/MIC and AUC/MPC for were 825 and 209.5, and for they were 825 and 425.8. Pradofloxacin would exceed the mutant selection window for >12-16 h. Pradofloxacin appears to have a low likelihood for resistance selection against key bovine respiratory disease bacterial pathogens based on low MIC and MPC values.
PubMed: 38787251
DOI: 10.3390/pathogens13050399 -
Frontiers in Microbiology 2024Bovine respiratory disease (BRD) is one of the most important animal health problems in the beef industry. While bacterial culture and antimicrobial susceptibility...
Bacterial enrichment prior to third-generation metagenomic sequencing improves detection of BRD pathogens and genetic determinants of antimicrobial resistance in feedlot cattle.
INTRODUCTION
Bovine respiratory disease (BRD) is one of the most important animal health problems in the beef industry. While bacterial culture and antimicrobial susceptibility testing have been used for diagnostic testing, the common practice of examining one isolate per species does not fully reflect the bacterial population in the sample. In contrast, a recent study with metagenomic sequencing of nasal swabs from feedlot cattle is promising in terms of bacterial pathogen identification and detection of antimicrobial resistance genes (ARGs). However, the sensitivity of metagenomic sequencing was impeded by the high proportion of host biomass in the nasal swab samples.
METHODS
This pilot study employed a non-selective bacterial enrichment step before nucleic acid extraction to increase the relative proportion of bacterial DNA for sequencing.
RESULTS
Non-selective bacterial enrichment increased the proportion of bacteria relative to host sequence data, allowing increased detection of BRD pathogens compared with unenriched samples. This process also allowed for enhanced detection of ARGs with species-level resolution, including detection of ARGs for bacterial species of interest that were not targeted for culture and susceptibility testing. The long-read sequencing approach enabled ARG detection on individual bacterial reads without the need for assembly. Metagenomics following non-selective bacterial enrichment resulted in substantial agreement for four of six comparisons with culture for respiratory bacteria and substantial or better correlation with qPCR. Comparison between isolate susceptibility results and detection of ARGs was best for macrolide ARGs in reads but was also substantial for sulfonamide ARGs within and reads and tetracycline ARGs in reads.
DISCUSSION
By increasing the proportion of bacterial DNA relative to host DNA through non-selective enrichment, we demonstrated a corresponding increase in the proportion of sequencing data identifying BRD-associated pathogens and ARGs in deep nasopharyngeal swabs from feedlot cattle using long-read metagenomic sequencing. This method shows promise as a detection strategy for BRD pathogens and ARGs and strikes a balance between processing time, input costs, and generation of on-target data. This approach could serve as a valuable tool to inform antimicrobial management for BRD and support antimicrobial stewardship.
PubMed: 38779502
DOI: 10.3389/fmicb.2024.1386319 -
Vaccines Apr 2024is a bovine respiratory pathogen commonly associated with bacterial bronchopneumonia. Current vaccine strategies have shown variable efficacy in feedlot cattle, and...
BACKGROUND
is a bovine respiratory pathogen commonly associated with bacterial bronchopneumonia. Current vaccine strategies have shown variable efficacy in feedlot cattle, and therefore novel vaccines are needed. spores have been investigated as a mucosal vaccine platform, due to their ability to bind and present antigens to the mucosa and act as an adjuvant. The aim of this study was to develop two spore-based mucosal vaccines targeting and evaluate their immunogenicity in mice.
METHODS
Two antigen constructs composed of cholera toxin B subunit, leukotoxin, and either the outer membrane protein PlpE (MhCP1) or GS60 (MhCP2) were synthesized, purified and then bound to spores as vaccines. In two separate mice trials, the spore-bound vaccines (Spore-MhCP1 and Spore-MhCP2) were administered to mice through intranasal and intragastric routes, while free antigens were administered intranasally and intramuscularly. Unbound spores were also evaluated intranasally. Antigen-specific serum IgG and mucosal IgA from bronchoalveolar lavage, feces, and saliva were measured after vaccination. Mice sera from all treatment groups were assessed for their bactericidal activity against .
RESULTS
In both mice experiments, intramuscular immunization induced the strongest serum IgG antibody response. However, the intranasal administration of Spore-MhCP1 and Spore-MhCP2 elicited the greatest secretory IgA-specific response against leukotoxin, PlpE, and GS60 in bronchoalveolar lavage, saliva, and feces ( < 0.05). Compared to the intranasal administration of free antigen, spore-bound antigen groups showed greater bactericidal activity against ( < 0.05).
CONCLUSIONS
Since intranasally delivered Spore-MhCP1 and Spore-MhCP2 elicited both systemic and mucosal immune responses in mice, these vaccines may have potential to mitigate lung infection in cattle by restricting colonization and proliferation in the respiratory tract. The efficacy of these mucosal spore-based vaccines merits further assessment against in cattle.
PubMed: 38675757
DOI: 10.3390/vaccines12040375 -
International Journal of Molecular... Apr 2024Bovine respiratory disease (BRD) is the leading cause of morbidity and mortality in cattle raised in North America. At the feedlot, cattle are subject to metaphylactic...
Bovine respiratory disease (BRD) is the leading cause of morbidity and mortality in cattle raised in North America. At the feedlot, cattle are subject to metaphylactic treatment with macrolides to prevent BRD, a practice that may promote antimicrobial resistance and has resulted in an urgent need for novel strategies. is one of the major bacterial agents of BRD. The inhibitory effects of two amphipathic, α-helical (PRW4, WRL3) and one β-sheet (WK2) antimicrobial peptides were evaluated against multidrug-resistant (MDR) isolated from Alberta feedlots. WK2 was not cytotoxic against bovine turbinate (BT) cells by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. All three peptides inhibited , with WK2 being the most efficacious against multiple isolates. At 8-16 µg/mL, WK2 was bactericidal against Mh 330 in broth, and at 32 µg/mL in the presence of BT cells, it reduced the population by 3 logs CFU/mL without causing cytotoxic effects. The membrane integrity of Mh 330 was examined using NPN (1-N-phenylnaphthylamine) and ONPG (o-Nitrophenyl β-D-galactopyranoside), with both the inner and outer membranes being compromised. Thus, WK2 may be a viable alternative to the use of macrolides as part of BRD prevention and treatment strategies.
Topics: Animals; Cattle; Anti-Bacterial Agents; Antimicrobial Peptides; Bovine Respiratory Disease Complex; Mannheimia haemolytica; Microbial Sensitivity Tests; Protein Conformation, alpha-Helical; Protein Conformation, beta-Strand
PubMed: 38673750
DOI: 10.3390/ijms25084164 -
Pathogens (Basel, Switzerland) Apr 2024Bovine respiratory disease (BRD) is the leading cause of mortality and antimicrobial drug (AMD) use in weaned dairy heifers. Limited information is available regarding...
Bovine respiratory disease (BRD) is the leading cause of mortality and antimicrobial drug (AMD) use in weaned dairy heifers. Limited information is available regarding antimicrobial resistance (AMR) in respiratory bacteria in this population. This study determined AMR gene presence in 326 respiratory isolates (, , and ) from weaned dairy heifers using whole genome sequencing. Concordance between AMR genotype and phenotype was determined. Twenty-six AMR genes for 8 broad classes of AMD were identified. The most prevalent, medically important AMD classes used in calf rearing, to which these genes predict AMR among study isolates were tetracycline (95%), aminoglycoside (94%), sulfonamide (94%), beta-lactam (77%), phenicol (50%), and macrolide (44%). The co-occurrence of AMR genes within an isolate was common; the largest cluster of gene co-occurrence encodes AMR to phenicol, macrolide, elfamycin, β-lactam (cephalosporin, penam cephamycin), aminoglycoside, tetracycline, and sulfonamide class AMD. Concordance between genotype and phenotype varied (Matthew's Correlation Coefficient ranged from -0.57 to 1) by bacterial species, gene, and AMD tested, and was particularly poor for fluoroquinolones (no AMR genes detected) and ceftiofur (no phenotypic AMR classified while AMR genes present). These findings suggest a high genetic potential for AMR in weaned dairy heifers; preventing BRD and decreasing AMD reliance may be important in this population.
PubMed: 38668255
DOI: 10.3390/pathogens13040300 -
TheScientificWorldJournal 2024species are frequently encountered as serious diseases in small ruminants. It is the main cause of respiratory pasteurellosis in sheep and goats of all age groups.
BACKGROUND
species are frequently encountered as serious diseases in small ruminants. It is the main cause of respiratory pasteurellosis in sheep and goats of all age groups.
METHODS
The cross-sectional study was conducted from December 2022 to April 2023 in Haramaya district, eastern Ethiopia, to isolate and identify and and estimate their prevalence, associated risk factors, and antimicrobial sensitivity of isolates in small ruminants using a purposive sampling method. A total of 384 samples (156 nasal swabs from clinic cases and 228 lung swabs from abattoir cases) were collected. STATA 14 software was used to analyze the data. In addition, multivariable logistic regression analysis was performed to assess an association of risk factors.
RESULTS
Out of the 384 samples examined, 164 were positive for pasteurellosis, resulting in a 42.70% prevalence. Similarly, 63 (38.4%) of the 164 positive results were from nasal swabs, while 101 (61.6%) came from lung samples. accounted for 126 (76.82%) of the isolates, while accounted for 38 (23.17%). Of the 63 nasal swab isolates, 33 (37%) were from goats and 30 (42.8%) were from sheep. And 17 (10.89%) and 46 (29.58%), respectively, were and . Of the 46 (40%) of the 101 (44.3%) isolates of the pneumonic lung, samples were from goats, while 55 (48.47%) were from sheep. In this study, the risk factors (species, age, and body condition score) were found to be significant ( < 0.05). isolates evaluated for antibiotic susceptibility were highly resistant to oxacillin (90.90%), followed by gentamycin (72.72%), and penicillin (63.63%). However, the isolates were highly sensitive to chloramphenicol (90.90%), followed by tetracycline (63.63%), and ampicillin (54.54%).
CONCLUSION
This study showed that and are the common causes of mannheimiosis and pasteurellosis in small ruminants, respectively, and isolates were resistant to commonly used antibiotics in the study area. Thus, an integrated vaccination strategy, antimicrobial resistance monitoring, and avoidance of stress-inducing factors are recommended.
Topics: Animals; Pasteurella multocida; Mannheimia haemolytica; Ethiopia; Sheep; Goats; Anti-Bacterial Agents; Cross-Sectional Studies; Microbial Sensitivity Tests; Sheep Diseases; Goat Diseases; Prevalence; Risk Factors; Pasteurella Infections
PubMed: 38655561
DOI: 10.1155/2024/5605552 -
Open Life Sciences 2024Bovine respiratory disease (BRD) is a significant veterinary challenge, often exacerbated by pathogen resistance, hindering effective treatment. Traditional testing...
Bovine respiratory disease (BRD) is a significant veterinary challenge, often exacerbated by pathogen resistance, hindering effective treatment. Traditional testing methods for primary pathogens - , , and - are notably time-consuming and lack the rapidity required for effective clinical decision-making. This study introduces a TaqMan MGB probe detection chip, utilizing fluorescent quantitative PCR, targeting key BRD pathogens and associated drug-resistant genes and sites. We developed 94 specific probes and primers, embedded into a detection chip, demonstrating notable specificity, repeatability, and sensitivity, reducing testing time to under 1 h. Additionally, we formulated probes to detect mutations in the quinolone resistance-determining region, associated with fluoroquinolone resistance in BRD pathogens. The chip exhibited robust sensitivity and specificity, enabling rapid detection of drug-resistant mutations in clinical samples. This methodology significantly expedites the diagnostic process for BRD and sensitive drug screening, presenting a practical advancement in the field.
PubMed: 38585641
DOI: 10.1515/biol-2022-0778 -
Frontiers in Microbiology 2024Data collected from the German national resistance monitoring program GE-Vet showed slowly increasing prevalence of macrolide resistance among bovine respiratory disease...
Data collected from the German national resistance monitoring program GE-Vet showed slowly increasing prevalence of macrolide resistance among bovine respiratory disease (BRD)-associated from cattle over the last decade. The focus of this study was to analyze the genetic basis of antimicrobial resistance (AMR) and the prevalence of multidrug-resistance (MDR)-mediating integrative and conjugative elements (ICEs) in 13 German BRD-associated isolates collected between 2009 and 2020 via whole-genome sequencing. Antimicrobial susceptibility testing (AST) was performed via broth microdilution according to the recommendations of the Clinical and Laboratory Standards Institute for the macrolides erythromycin, tilmicosin, tulathromycin, gamithromycin, tildipirosin, and tylosin as well as 25 other antimicrobial agents. All isolates either had elevated MICs or were resistant to at least one of the macrolides tested. Analysis of whole-genome sequences obtained by hybrid assembly of Illumina MiSeq and Oxford Nanopore MinION reads revealed the presence of seven novel Tn-like ICEs, designated Tn, and Tn- Tn. These ICEs harbored the antimicrobial resistance genes (T), (C), (G), (Y), and in different combinations. In addition, mutational changes conferring resistance to macrolides, nalidixic acid or streptomycin, respectively, were detected among the . isolates. In addition, four isolates carried a 4,613-bp plasmid with the β-lactamase gene . The detection of the macrolide resistance genes (T), (C), and (G) together with other resistance genes on MDR-mediating ICEs in bovine may explain the occurrence of therapeutic failure when treating BRD with regularly used antimicrobial agents, such as phenicols, penicillins, tetracyclines, or macrolides. Finally, pathogen identification and subsequent AST is essential to ensure the efficacy of the antimicrobial agents applied to control BRD in cattle.
PubMed: 38495516
DOI: 10.3389/fmicb.2024.1356208 -
Frontiers in Veterinary Science 2024Despite the fact that pneumonia remains a leading cause of mortality and morbidity in pre-weaned calves, relatively little is known regarding the effects of the...
Investigation into the safety, and serological responses elicited by delivery of live intranasal vaccines for bovine herpes virus type 1, bovine respiratory syncytial virus, and parainfluenza type 3 in pre-weaned calves.
Despite the fact that pneumonia remains a leading cause of mortality and morbidity in pre-weaned calves, relatively little is known regarding the effects of the concurrent administration of intranasal pneumonia virus vaccines, particularly in calves with high levels of maternally derived antibodies. The objective of this study was to use a cohort of 40 dairy and dairy-beef female and male calves (27 females and 13 males) to determine serological responses to concurrent administration at 3 weeks of age (22 ± 4.85 days) of two commercially available intranasal (IN) vaccines for the viruses: bovine respiratory syncytial virus (BRSV), bovine herpes virus 1 (BoHV-1), and parainfluenza-3-virus (PI3-V). The study groups were as follows: (i) Bovilis IBR Marker Live only® (IO), (ii) Bovilis INtranasal RSP Live® only (RPO), (iii) Concurrent vaccination with Bovilis IBR Marker Live® & Bovilis Intranasal RSP Live® (CV), and (iv) a control group of non-vaccinated calves (CONT). The calves' serological response post-IN vaccination, clinical health scores, rectal temperatures, and weights were measured. Data were analyzed in SAS using mixed models and logistic regression. The CV calves had an average daily weight gain (ADG) of 0.74 (±0.02) kg, which was similar to CONT (0.77 ± 0.02 kg). Despite no significant differences in the antibody levels between study groups 3 weeks post-IN vaccination, following the administration of subsequent parenteral injections in the form of Bovilis Bovipast RSP®(antigens; inactivated BRSV, inactivated PI3-V, inactivated ) and Bovilis IBR Marker Live®, the antibody levels of the BRSV and PI3-V increased in both the CV and RPO study groups. Concurrent vaccination resulted in no increase in fever and no difference in health scores when compared to CONT.
PubMed: 38464703
DOI: 10.3389/fvets.2024.1283013