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226 result(s) for "Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - veterinary"
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Identification of Enterococcus spp. by MALDI-TOF mass spectrometry isolated from clinical mastitis and bulk tank milk samples
Background Throughout a three-year study period, 1,577 bovine clinical mastitis samples and 302 bulk tank samples were analyzed from ten Brazilian dairy herds. Enterococcus spp. was isolated and identified in 93 (5.9%) clinical mastitis samples. In addition, 258 Enterococcus spp. were isolated from the bulk tank samples of the same herds. The identification of Enterococcus spp. isolated from bulk tanks and milk samples of clinical mastitis were accomplished by phenotypic characteristics and confirmed by MALDI-TOF Mass Spectrometry (MS). Fisher test was performed to verify the difference between bulk tanks and mastitis samples. Results The following species were identified from clinical mastitis: E. saccharolyticus (62.4%), E. faecalis (19.4%), E. faecium (15.1%), E. hirae (1.1%), E. mundtii (1.1%), E. durans (1.1%). Furthermore, from 258 bulk tank milk samples, eight enterococci species were isolated: E. faecalis (67.8%), E. hirae (15.1%), E. faecium (4.6%), E. saccharolyticus (4.6%), E. mundtii (3.1%), E. caseliflavus ( 2.7%), E. durans (1.2%), E. galinarum (0.8%). Conclusions The difference in species predominance in bulk tank samples (67.8% of E. faecalis ) and clinical mastitis (62.4% of E. saccharolyticus ) was unexpected and caught our attention. Although Enterococcus spp. are traditionally classified as an environmental mastitis agent, in the present study, E. saccharolyticus behaved as a contagious agent of mastitis, which consequently changed the control patterns to be implemented.
Accuracy of two Sepsityper MALDI-TOF MS methods for bacterial identification in bloodstream infections in dogs, foals, and calves using Bayesian latent class model
Accurate diagnosis of bloodstream infections is crucial for survival and antimicrobial de-escalation in veterinary medicine. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry enables faster identification of bacteria in BSIs. This study aimed to compare diagnostic accuracy of two Sepsityper ® methods (Rapid Sepsityper ® and Sepsityper ® Extraction) with conventional culture method for bacterial identification in clinical samples. Mean time-to-positivity and frequency of bacteria in BSIs were also determined. This diagnostic test study used bloodstream infection samples from 385 critically ill animals (121 dogs, 119 foals, and 145 calves) admitted to the Faculty of Veterinary Medicine, Ghent (October 2021-February 2024). Accuracy was compared using Bayesian latent class model with priors for sensitivity (99.9%) and specificity (96.0%) based on literature, and a prevalence of 26.0%. Conventional culture method identified 173 bacteria with Escherichia coli (19.1%,33/173), Staphylococcus spp. (12.1%,21/173) and Streptococcus spp. (8.1%,14/173) being most common. Sensitivity of Rapid Sepsityper ® , Sepsityper ® Extraction, and conventional culture method was 62.1%, 86.1%, and 97.4%, respectively. Specificity was 94.3%, 90.4% and 92.3%, and accuracy was 85.8%, 89.3%, and 93.6%, respectively. Mean time-to-positivity and ±standard deviation for blood cultures flagging positive was 21h25min ±17.8h. Rapid Sepsityper ® identified bacteria in approximately 30min, while Sepsityper ® Extraction method required around 50min, and conventional culture method needed 12-48h. Altogether, Sepsityper ® Extraction shows promise given the sensitivity and results were delivered more rapidly than conventional culture. Enhancing diagnostic workflow, resulting in a better prognosis, reduced hospital stays, and lower healthcare costs due to more rational use of (critically important) antimicrobials.
Genetic diversity and population structure of Tenacibaculum maritimum, a serious bacterial pathogen of marine fish: from genome comparisons to high throughput MALDI-TOF typing
Tenacibaculum maritimum is responsible for tenacibaculosis, a devastating marine fish disease. This filamentous bacterium displays a very broad host range and a worldwide geographical distribution. We analyzed and compared the genomes of 25 T. maritimum strains, including 22 newly draft-sequenced genomes from isolates selected based on available MLST data, geographical origin and host fish. The genome size (~3.356 Mb in average) of all strains is very similar. The core genome is composed of 2116 protein-coding genes accounting for ~75% of the genes in each genome. These conserved regions harbor a moderate level of nucleotide diversity (~0.0071 bp −1 ) whose analysis reveals an important contribution of recombination (r/m ≥ 7) in the evolutionary process of this cohesive species that appears subdivided into several subgroups. Association trends between these subgroups and specific geographical origin or ecological niche remains to be clarified. We also evaluated the potential of MALDI-TOF-MS to assess the variability between T. maritimum isolates. Using genome sequence data, several detected mass peaks were assigned to ribosomal proteins. Additionally, variations corresponding to single or multiple amino acid changes in several ribosomal proteins explaining the detected mass shifts were identified. By combining nine polymorphic biomarker ions, we identified combinations referred to as MALDI-Types (MTs). By investigating 131 bacterial isolates retrieved from a variety of isolation sources, we identified twenty MALDI-Types as well as four MALDI-Groups (MGs). We propose this MALDI-TOF-MS Multi Peak Shift Typing scheme as a cheap, fast and an accurate method for screening T. maritimum isolates for large-scale epidemiological surveys.
Salivary peptidomic profiling of chronic gingivostomatitis in cats by matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry and nanoscale liquid chromatography-tandem mass spectrometry
Abstract Background Chronic gingivostomatitis in cats (FCGS) is a moderately to severely painful condition, potentially caused by inadequate immune response to oral antigenic stimulation. Salivary peptidome analysis can identify inflammatory protein mediators and pathways involved in oral mucosal immune activation and may indicate potential therapeutic options for FCGS. Objective Evaluate the diversity and abundance of salivary peptides in cats with FCGS using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) and nanoscale liquid chromatography-tandem mass spectrometry (nano LC-MS/MS). Animals Thirty-two cats with FCGS and 18 healthy controls. Methods Case-control cross-sectional study. We compared the salivary peptide profiles of diseased and healthy cats. The diagnosis of FCGS was confirmed by histopathology. Saliva samples were analyzed for viral infections using polymerase chain reaction (PCR), peptide mass fingerprint (PMF) using MALDI-TOF MS, and peptide identification using nano LC-MS/MS. Results Distinct clusters of peptide profiles were observed between groups. In FCGS, 26 salivary peptides were altered, including apolipoprotein A1, nuclear receptor subfamily 1 group I member 3, fibrinogen alpha chain, interleukin 2 receptor gamma, interleukin 23 receptor, hemoglobin subunit alpha, and serpin peptidase inhibitor clade A (alpha-1 antiproteinase, antitrypsin) member 12, protein-tyrosine-phosphatase, and cholinergic receptor nicotinic alpha 10 subunit. Protein-anti-inflammatory drug interaction networks were observed. Conclusions and Clinical Importance Peptide mass fingerprint and peptide profiles identified distinct clusters between FCGS and healthy cats. The 9 novel salivary peptide markers were associated with the JAK/STAT and PI3K/Akt pathways and immune responses. These potentially noninvasive biomarkers may facilitate understanding of FCGS pathophysiology and guide future therapeutic research.
Loop-mediated isothermal amplification assay coupled with lateral flow dipstick for the rapid detection of methicillin-resistant Staphylococcus pseudintermedius from dogs
Staphylococcus pseudintermedius is a global animal pathogen. Traditional identification methods are time-consuming necessitating a more efficient approach. This study validated and enhanced the loop-mediated isothermal amplification (LAMP) technique by integration it with a lateral flow dipstick (LFD) assay for the detection of S. pseudintermedius and methicillin-resistant S. pseudintermedius (MRSP) strains. Conventional identification methods were compared with LAMP and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The isolates were tested for MRSP detection using oxacillin and cefoxitin disk diffusion tests alongside the LAMP assay targeting the mecA gene, a marker for methicillin resistance. Results showed that LAMP combined with LFD effectively detected S. pseudintermedius and MRSP. This study identified 53 isolates as S. pseudintermedius by conventional and LAMP methods, with MALDI-TOF MS correctly identifying 39.62% (21/53). The mecA gene, crucial for methicillin resistance, was detected in all PCR-positive isolates ( n  = 33) by LAMP, while the disk diffusion method identified 69.70% (23/33) of mecA -positive strains. LAMP and conventional methods exhibited superior accuracy, sensitivity, and specificity (all 100%) compared to MALDI-TOF MS, which showed lower sensitivity (39.62%) for S. pseudintermedius identification. Similarly, the LAMP assay demonstrated higher accuracy, sensitivity, and specificity (all 100%) for MRSP detection compared to the disk diffusion method (83.33%, 69.70%, and 94.87%, respectively). The LAMP assay coupled with the LFD method proved suitable for routine bacterial identification in laboratories, offering adequate sensitivity and specificity with simple steps and short reaction time.
An update on non-aureus staphylococci and mammaliicocci in cow milk: unveiling the presence of Staphylococcus borealis and Staphylococcus rostri by MALDI-TOF MS
Non-aureus staphylococci and mammaliicocci (NASM) are the microorganisms most frequently isolated from milk. Given their numerosity and complexity, MALDI-TOF MS is one of the preferred species identification approaches. Nevertheless, reference mass spectra for the novel species Staphylococcus borealis were included only recently in the Bruker Biotyper System (MBT) library, and other species of veterinary interest such as S. rostri are still absent. This work provides an updated picture of the NASM species found in milk, gained by retrospectively analyzing the data relating to 21,864 milk samples, of which 6,278 from clinical mastitis (CM), 4,039 from subclinical mastitis (SCM), and 11,547 from herd survey (HS), with a spectrum library including both species. As a result, S. borealis was the second most frequently isolated NASM (17.07%) after S. chromogenes (39.38%) in all sample types, with a slightly higher percentage in CM (21.84%), followed by SCM (17.65%), and HS (14.38%). S. rostri was also present in all sample types (3.34%), reaching 8.43% of all NASM in SCM and showing a significant association (p < 0.01) with this condition. Based on our findings, the presence of S. borealis and S. rostri in milk and their potential association with mastitis might have been overlooked, possibly due to the difficulties in differentiating these species from other closely related NASM. Our results indicate that S. borealis could be a more frequent contributor to bovine udder infections than previously thought and that S. rostri should also not be underestimated considering its significant association with SCM.
Two cases of bloodstream infections associated with opportunistic bacterial species (Enterococcus hirae and Enterobacter xiangfangensis) in companion animals
Background Bloodstream infections are a matter of concern in small animal veterinary practice. Few reports are avaiable, especially regarding the role of opportunistic bacteria in becoming infectious. This report aims to add to the current veterinary literature on two opportunistic bacterial species ( Enterococcus hirae and Enterobacter xiangfangensis) associated with bloodstream infections in small animals admitted to the Bologna University Veterinary Hospital. Case presentation In the first case, a 15-year-old, immunocompromised, cardiopathic dog was admitted to the hospital for anorexia and diarrhea. The patient had a history of previous surgery and hospitalization. After three days, hyperthermia, leukopenia and hyperlactatemia were recorded, and blood culture revealed positivity for Enterococcus hirae , identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The patient’s general conditions progressively worsened, and the patient was euthanized. In the second case, a 2-year-old cat with chronic ocular herpesvirus infection and hypertrophic cardiomyopathy was admitted to the hospital for anorexia and hyperthermia. The cat was hospitalized one week before and received antimicrobial treatment for urinary tract infection by Staphylococcus felis . Hypokalemia and lymphopenia were also diagnosed. The patient progressively improved and was discharged after three days. On the same day, blood culture taken at admission revealed positivity for Enterobacter xiangfangensis , identified using MALDI-TOF MS. After five days, the patient returned with neurological symptoms, hypothermia and bradycardia, and was euthanized. Conclusions In small animal veterinary practice, the impact of opportunistic bacterial agents (such as E.hirae and E.xiangfangensis ) on bloodstream infections remains unclear. As in human medicine, they can be contracted in every healthcare setting and considered hospital-acquired infections. In this report, we highlighted the threat they pose especially in patients with multiple risk factors. Rapid and accurate diagnostic tools (such as MALDI-TOF MS) could be particularly important for reducing the severity of the infections.
Proteomic profiles of unilateral cryptorchidism in pigs at different ages using MALDI-TOF mass spectrometry and in-gel digestion coupled with mass spectrometry (GeLC-MS/MS) approaches
Background Cryptorchidism is a condition that occurs when one or both testes fail to descend into the scrotum. It is a common congenital disorder, causing economic loss in pig production. However, there have been only limited studies of differential protein expression profiles in undescended testes (UDTs) in the abdomen and descended testes (DTs) in cryptorchid pigs, especially at the peptidome and proteome levels. The present study aimed to analyze the peptidome of UDTs and DTs in unilateral cryptorchid pigs aged 1–2, 6, 15 and 20 weeks and in normal testes of healthy pigs aged 1–2 and 12 weeks, using peptide mass fingerprinting and three-dimensional principal component analysis (3D-PCA) with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, and to identify potential protein candidates, using in-gel digestion coupled with mass spectrometry (GeLC-MS/MS). Western blot analysis was used to verify protein expression. Protein sequence was affirmed by liquid chromatography–tandem mass spectrometry. Results A PCA plot showed a discrete cluster for each sample group. Peptide mass fingerprints (PMFs) demonstrated unique peptide fragments in UDTs at different ages. A number of markedly expressed proteins from GeLC-MS/MS were identified, including the multifunctional tumor necrosis factor receptor superfamily member 18 (TNFRSF18), in DTs at 1–2 and 6 weeks and in UDTs at 15 and 20 weeks of age. Using western blot analysis, high expression of TNFRSF18 was observed in the UDTs at 15 weeks. Using the STITCH database, this protein was found to be related to apoptosis, corresponding to the previous report in the UDTs at the same age. Conclusions The present study revealed the specific PMFs and clusters for porcine cryptorchidism, and a novel protein, TNFRSF18, associated with the disease mechanism. These results could provide further insights into the pathogenesis of the disease.
Fructose-1,6-bisphosphate aldolase encoded by a core gene of Mycoplasma hyopneumoniae contributes to host cell adhesion
Mycoplasma hyopneumoniae is an important respiratory pathogen that causes great economic losses to the pig industry worldwide. Although some putative virulence factors have been reported, pathogenesis remains poorly understood. Herein, we evaluated the relative abundance of proteins in virulent 168 (F107) and attenuated 168L (F380) M. hyopneumoniae strains to identify virulence-associated factors by two-dimensional electrophoresis (2-DE). Seven proteins were found to be ≥ 1.5-fold more abundant in 168, and protein–protein interaction network analysis revealed that all seven interact with putative virulence factors. Unexpectedly, six of these virulence-associated proteins are encoded by core rather than accessory genomic elements. The most differentially abundant of the seven, fructose-1,6-bisphosphate aldolase (FBA), was successfully cloned, expressed and purified. Flow cytometry demonstrated the surface localisation of FBA, recombinant FBA (rFBA) mediated adhesion to swine tracheal epithelial cells (STEC), and anti-rFBA sera decreased adherence to STEC. Surface plasmon resonance showed that rFBA bound to fibronectin with a moderately strong K D of 469 nM. The results demonstrate that core gene expression contributes to adhesion and virulence in M. hyopneumoniae , and FBA moonlights as an important adhesin, mediating binding to host cells via fibronectin.
Investigation of coagulation and proteomics profiles in symptomatic feline hypertrophic cardiomyopathy and healthy control cats
Background Hypertrophic cardiomyopathy (HCM) is a crucial heart disease in cats. The clinical manifestations of HCM comprise pulmonary edema, dyspnea, syncope, arterial thromboembolism (ATE), and sudden cardiac death. D-dimer and prothrombin time (PT) are powerful biomarkers used to assess coagulation function. Dysregulation in these two biomarkers may be associated with HCM in cats. This study aims to assess D-dimer levels, PT, and proteomic profiling in healthy cats in comparison to cats with symptomatic HCM. Results Twenty-nine client-owned cats with HCM were enrolled, including 15 healthy control and 14 symptomatic HCM cats. The D-dimer concentration and PT were examined. Proteomic analysis was conducted by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry and liquid chromatography-tandem mass spectrometry (LC-MS/MS). In symptomatic cats, D-dimer levels were statistically significantly higher (mean ± SEM: 372.19 ng/ml ± 58.28) than in healthy cats (mean ± SEM: 208.54 ng/ml ± 10.92) with P-value of less than 0.01, while PT was statistically significantly lower in symptomatic cats (mean ± SEM: 9.8 s ± 0.15) compared to healthy cats (mean ± SEM: 11.08 s ± 0.23) with P-value of less than 0.0001. The proteomics analysis revealed upregulation of integrin subunit alpha M (ITGAM), elongin B (ELOB), and fibrillin 2 (FBN2) and downregulation of zinc finger protein 316 (ZNF316) and ectonucleoside triphosphate diphosphohydrolase 8 (ENTPD8) in symptomatic HCM cats. In addition, protein-drug interaction analysis identified the Ras signaling pathway and PI3K-Akt signaling pathway. Conclusions Cats with symptomatic HCM have higher D-dimer and lower PT than healthy cats. Proteomic profiles may be used as potential biomarkers for the detection and management of HCM in cats. The use of D-dimer as a biomarker for HCM detection and the use of proteomic profiling for a better understanding of disease mechanisms remain to be further studied in cats.