The outer membrane protein of Fusobacterium necrophorum, 43K OMP, stimulates inflammatory cytokine production through nuclear factor kappa B activation.

OBJECTIVE: Fusobacterium necrophorum causes bovine hepatic abscess, foot rot, mastitis, and endometritis. The 43 kDa outer membrane protein (43 K OMP) of F. necrophorum is a porin protein that plays an important role in infections by this bacterium, but the biological function and the pathogenesis of this protein are largely unknown. METHODS: In this study, we investigated the role of the 43 K OMP in bacterial infection of bovine mammary epithelial cells (MAC-T cells) by Tandem Mass Tag proteomic analysis. The RAW264.7 cells were incubated with recombinant 43 K OMP (12.5 µg/mL) for 2 h, 4 h, 6 h, and 12 h, and then the inflammatory related protein and inflammatory cytokine production were measured by Western blot analysis and ELISA, the mRNA expression levels of inflammatory cytokine were measured by Real-Time PCR. RESULTS: Proteomic analysis results demonstrated there were 224 differentially expressed proteins in the MAC-T cells stimulated with the 43 K OMP compared with control, and 118 proteins were upregulated and 106 proteins were downregulated. These differentially expressed proteins were mainly involved in NF-kappa B signaling, bacterial invasion of epithelial cells, cell adhesion, complement and coagulation cascades. The top six differentially expressed proteins were; MMP9, PLAU, STOM, PSMD13, PLAUR, and ITGAV, which were involved in a protein-protein interaction network. Furthermore, TLR/MyD88/NF-κB pathway related proteins and inflammatory cytokines (IL-6, TNF-α, and IL-1ß) were assessed by Western blot analysis and ELISA. Results showed the 43 K OMP to enhance the expression of TLR4 protein at 2 h (P < 0.01) and the MyD88 protein at 4 h (P < 0.05) post-stimulation, and to decrease IκBα expression at 4 h, 6 h and 12 h (P < 0.05) post-infection, as well as induce phosphorylation at Ser536 (P < 0.01). Levels of IL-6, IL-1ß, and TNF-α in the supernatants of mouse macrophages were increased (P < 0.05), as were mRNA expression levels of IL-6, IL-1ß, and TNF-α (P < 0.05), while IL-4 mRNA expression was decreased (P < 0.05). CONCLUSIONS: Taken together, these results suggested the important role for 43 K OMP in F. necrophorum infection, promoting the production of pro-inflammatory cytokines (IL-6 and TNF-α) by activation of the TLR/MyD88/NF-κB pathway. These findings provided a theoretical basis for a better understanding of the pathogenesis of F. necrophorum infection.

Liver X receptor α participates in LPS-induced reduction of triglyceride synthesis in bovine mammary epithelial cells.

Lipopolysaccharides (LPS) could induce milk fat depression via regulating the body and blood fat metabolism. However, it is not completely clear how LPS might regulate triglyceride synthesis in dairy cow mammary epithelial cells (DCMECs). DCMECs were isolated and purified from dairy cow mammary tissue and treated with LPS. The level of triglyceride synthesis, the expression and activity of the liver X receptor α (LXRα), enzymes related to de novo fatty acid synthesis, and the expression of the fatty acid transporters were investigated. We found that LPS decreased the level of triglyceride synthesis via a down-regulation of the transcription, translation, and nuclear translocation level of the LXRα. The results also indicated that the transcription level of the LXRα target genes, sterol regulatory element binding protein 1 (SREBP1), fatty acid synthetase (FAS), acetyl-CoA carboxylase-1 (ACC1), were significantly down-regulated in DCMECs after LPS treatment. Our data may provide new insight into the mechanisms of milk fat depression caused by LPS.

Screening of BHK-21 cellular proteins that interact with outer membrane protein 43K OMP of Fusobacterium necrophorum.

Fusobacterium necrophorum is a Gram negative, spore-free, anaerobic bacterium that can cause pyogenic and necrotic infections in animals and humans. It is a major bovine pathogen and causes hepatic abscesses, foot rot, and necrotic laryngitis. The 43K OMP of F. necrophorum is an outer membrane protein with molecular weight of 43 kDa, exhibiting similarity to pore-forming proteins of other Fusobacterium species that plays an important role in bacterial infections. However, the role of 43K OMP in F. necrophorum adhesion remains unknown. In this study, we evaluated whether the 43K OMP of F. necrophorum mediates adhesion to BHK-21 cells and performed a preliminary screen of the proteins that interact with 43K OMP of F. necrophorum by immunoprecipitation-mass spectrometry. The results showed that the natural 43K OMP and recombinant 43K OMP could bind to BHK-21 cells, and preincubation of F. necrophorum with an antibody against the recombinant 43K OMP of F. necrophorum decreased binding to BHK-21 cells. Seventy differential interacting proteins were successfully screened by immunoprecipitation-mass spectrometry. Among these seventy differential interacting proteins, seven cell membrane proteins and four extracellular matrix proteins shown to be relevant to bacteria adhesion through subcellular localization and single-molecule function analysis. These data increase our understanding of the pathogenesis of F. necrophorum and provide a new theoretical basis for the design of antimicrobial drugs against F. necrophorum.

LPS-induced reduction of triglyceride synthesis and secretion in dairy cow mammary epithelial cells via decreased SREBP1 expression and activity.

Sterol regulatory element binding protein 1 (SREBP1) has a central regulatory effect on milk fat synthesis. Lipopolysaccharides (LPS) can induce mastitis and cause milk fat depression in cows. SREBP1 is also known to be associated with inflammatory regulation. Thus, in the current study, we hypothesized that LPS-induced milk fat depression in dairy cow mammary epithelial cells (DCMECs) operates via decreased SREBP1 expression and activity. To examine the hypothesis, DCMECs were isolated and purified from dairy cow mammary tissue and treated with LPS (10 µg/ml). LPS treatment of DCMECs suppressed lipid-metabolism-related transcription factor SREBP1 mRNA expression, nuclear translocation and protein expression, leading to reduced triglyceride content. The transcription levels of acetyl-CoA carboxylase-1 and fatty acid synthetase were significantly down-regulated in DCMECs after LPS treatment, suggesting that acetyl-CoA carboxylase-1 and fatty acid synthetase involved in de novo milk fat synthesis was regulated by SREBP1. In summary, these results suggest that LPS induces milk fat depression in dairy cow mammary epithelial cells via decreased expression of SREBP1 in a time-dependent manner.

Extremely preterm infants born outside a provincial tertiary perinatal center and transferred postnatally associated with poor outcomes: a real-world observational study.

Introduction: Extremely preterm infants (EPIs) have high morbidity and mortality, and are recommended to be born in a tertiary perinatal center (inborn). However, many EPIs in central China are born in lower-level hospitals and transferred postnatally, the outcomes of which remain to be investigated. Methods: EPIs admitted to the Department of Neonatology, Maternal and Child Health Hospital of Hubei Province from January 2013 to December 2022 were retrospectively recruited and divided into the control (inborn) and transfer groups (born in other hospitals). The neonatal and maternal characteristics, neonatal outcomes, and the treatment of survival EPIs were analyzed. Results: A total of 174 and 109 EPIs were recruited in the control and transfer groups, respectively. EPIs in the transfer group have a higher birth weight and a lower proportion of multiple pregnancies than the control group (all P < 0.05). The proportions of antenatal steroids, magnesium sulfate, cesarean delivery, premature rupture of membranes ≥18 h, gestational diabetes, and amniotic fluid abnormalities were lower in the transfer group (all P < 0.05). Survival rates (64.22% vs. 56.32%), proportions of severe periventricular-intraventricular hemorrhage (PIVH) (11.93% vs. 11.49%), severe bronchopulmonary dysplasia (sBPD) (21.05% vs. 20%), and severe retinopathy of prematurity (ROP) (24.77% vs. 20.11%) were similar in the transfer and control groups (all P > 0.05). However, the transfer group had higher proportions of severe birth asphyxia (34.86% vs. 13.22%, P < 0.001), PIVH (42.20% vs. 29.89%, P = 0.034), and extrauterine growth retardation (EUGR) (17.43% vs. 6.32%, P = 0.003). Less surfactant utilization was found in the transfer group among survival EPIs (70.00% vs. 93.88%, P < 0.001). Conclusion: EPIs born outside a tertiary perinatal center and transferred postnatally did not have significantly higher mortality and rates of severe complications (severe PIVH, severe ROP, and sBPD), but there may be an increased risk of severe asphyxia, PIVH and EUGR. This may be due to differences in maternal and neonatal characteristics and management. Further follow-up is needed to compare neurodevelopmental outcomes, and it is recommended to transfer the EPIs in utero to reduce the risk of poor physical and neurological development.

Virus-binding activity of the truncated C subunit of porcine aminopeptidase N expressed in Escherichia coli.

Seven overlapping truncated forms of the C subunit of porcine aminopeptidase N (pAPN-C) were expressed in Escherichia coli. By western blotting and ELISA test, all recombinant proteins were recognized by the antibody against native porcine aminopeptidase N. Recombinant proteins, rpAPN-C2 (aa 623-722) and rpAPN-C3 (aa 673-772), had the highest binding activity with swine transmissible gastroenteritis virus among the truncated pAPN-C recombinant proteins. The overlapping region (aa 673-722) between rpAPN-C2 and rpAPN-C3 is indicated to play a key role in viral binding.

Fusobacterium necrophorum Promotes Apoptosis and Inflammatory Cytokine Production Through the Activation of NF-κB and Death Receptor Signaling Pathways.

Fusobacterium necrophorum can cause liver abscess, foot rot in ruminants, and Lemire syndrome in humans, Also, its virulence factors can induce the apoptosis of macrophages and neutrophils. However, the detailed mechanism has not been fully clarified. This study investigated the mechanisms of apoptosis and inflammatory factor production in F. necrophorum-induced neutrophils and macrophages (RAW246.7). After infection of macrophages with F. necrophorum, 5-ethynyl-2'-deoxyuridine labeling assays indicated that F. necrophorum inhibited macrophage proliferation in a time- and dose-dependent manner. Hoechst staining and DNA ladder assays showed significant condensation of the nucleus and fragmentation of genomic DNA in F. necrophorum-infected macrophages, Annexin V (FITC) and propidium iodide (PI) assay confirmed the emergence of apoptosis in the macrophages and sheep neutrophils with F. necrophorum compared with the control. The group with significant apoptosis was subjected to RNA sequencing (RNA-Seq), and the sequencing results revealed 2581 up- and 2907 downregulated genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis of the differentially expressed genes showed that F. necrophorum drove apoptosis and production of inflammatory factors by activating genes related to the Nuclear Factor-κB (NF-κB) and death receptor pathways. Meanwhile, quantitative reverse transcription PCR and Western blot validation results were consistent with the results of transcriptome sequencing analysis. In conclusion, F. necrophorum induced apoptosis and production of pro-inflammatory factors through the NF-κB and death receptor signaling pathway, providing a theoretical basis for further mechanistic studies on the prevention and control of F. necrophorum disease treatment.

Interaction of 43K OMP of Fusobacterium necrophorum with fibronectin mediates adhesion to bovine epithelial cells.

Fusobacterium necrophorum, a Gram-negative anaerobe, is an important bovine pathogen that causes hepatic abscesses, foot rot, mastitis and endometritis. We have previously shown that the 43 kDa outer membrane protein (43 K OMP) of F. necrophorum is a porin protein that plays an important role in bacterial infections; however, the molecular mechanisms by which this protein mediates adhesion remain unclear. In this study, we investigated the role of 43 K OMP in F. necrophorum adhesion to bovine epithelial cells using 43 K OMP-deficient mutants, and identified the protein that interacts with 43 K OMP by immunoprecipitation-mass spectrometry. Our results indicated that the native 43 K OMP and recombinant 43 K OMP could bind to the cell membrane of MAC-T or bovine endometrial epithelial cells (BEECs). When F. necrophorum was preincubated with antibodies against the recombinant 43 K OMP or bovine epithelial cells were preincubated with 43 K OMP, the adhesion of F. necrophorum to MAC-T or BEECs decreased significantly (P<0.01). We successfully constructed a 43 K OMP-deficient strain (A25Δ43 K OMP) and bacterial attachment to MAC-T or BEECs was significantly higher with the F. necrophorum A25 strain than with mutant strain A25Δ43 K OMP (P<0.01). The deficiency of 43 K OMP reduced the binding of F. necrophorum to bovine epithelial cells by 90.5 %-94.9 %. Among the 39 potential differential proteins, fibronectin, collagen and myosin were selected as the target proteins, and direct interaction between 43 K OMP of F. necrophorum and fibronectin was demonstrated. Taken together, these results suggest that 43 K OMP plays a key role in adhesion of F. necrophorum to bovine epithelial cells through its interaction with fibronectin. These findings provide a theoretical basis for the pathogenic mechanism of F. necrophorum.

Evaluation of Immunoprotective Effects of Fusobacterium necrophorum Outer Membrane Proteins 43K OMP, Leukotoxin and Hemolysin Multi-Component Recombinant Subunit Vaccine in Mice.

We evaluated the efficacy of three vaccine formulations containing different combinations of proteins (43K OMP, leukotoxin recombinant protein PL4 and hemolysin recombinant protein H2) and killed whole cell Fusobacterium necrophorum in preventing liver abscess. Four subcutaneous vaccines were formulated: vaccine 1 (43K OMP), vaccine 2 (PL4 and H2), vaccine 3 (43K OMP, PL4 and H2), and vaccine 4 (killed whole bacterial cell). 43K OMP, PL4, and H2 proteins were produced by using recombinant protein expression. To evaluate vaccine efficacy, we randomly allocated 50 BALB/c female mice to one of five different treatment groups: PBS control group, vaccine 1, vaccine 2, vaccine 3, and vaccine 4. Mice were vaccinated three times, with 14 days between each immunization. After immunization, the mice were challenged with F. necrophorum. The three key findings of this study are as follows: (1) Vaccine 3 has enabled mice to produce higher antibody titer following bacterial challenge, (2) in the liver pathology of mice, the vaccine 3 liver showed the least pathology, and (3) all four vaccines produced high levels of antibodies and cytokines in mice, but the level of vaccine 3 was the highest. Based on our results, it has been demonstrated that a mixture of F. necrophorum 43K OMP, PL4, and H2 proteins inoculated with mice can achieve protection against liver abscess in mice. Our research may therefore provide the basis for the development of a vaccine against F. necrophorum bovine infections.

Selenium Deficiency in Chickens Induces Intestinal Mucosal Injury by Affecting the Mucosa Morphology, SIgA Secretion, and GSH-Px Activity.

The small intestine is one of the target organs of dietary selenium (Se) deficiency. Our objective was to investigate the effects of Se deficiency on small intestinal mucosa morphology and function in chickens. In the present study, 1-day (d)-old chickens were fed either a commercial diet with 0.15 mg/kg Se (control group) or a Se-deficient diet with 0.016 mg/kg Se (Se-group). The average daily weight gain, Se content in the blood, secretory immunoglobulin A (SIgA) secretion, and glutathione peroxidase (GSH-Px) activity in the small intestine in chickens were examined after 10, 20, 30, and 40 days of feeding. We also observed the morphology of the small intestine and recorded the number of intraepithelial lymphocytes (IELs). The average daily weight gain decreased; the level of Se in the blood decreased significantly; and SIgA secretion and GSH-Px activity in the duodenum, jejunum, and ileum decreased to different degrees. Histological analysis showed that the villus length, crypt depth, mucosal thickness, and number of IELs in the small intestine decreased to different extents in different periods. In the Se-group, longer feeding times were associated with more severe injury to physiological structure and function in the intestinal mucosa in chickens. In conclusion, Se deficiency induced injury of the mucosal immune barrier and physical barrier of the small intestine, and decreased the growth performance and antioxidant capacity in chickens.

Selenium deficiency induces duodenal villi cell apoptosis via an oxidative stress-induced mitochondrial apoptosis pathway and an inflammatory signaling-induced death receptor pathway.

Selenium (Se) is an important nutritional trace element possessing antioxidant properties. Our goal was to elucidate the effect and mechanism of Se deficiency on the intestinal cell fate. One-day-old three-yellow chickens were fed a low Se diet for 1, 3, and 5 weeks. Histologic characteristics, protein expression profiles, antioxidant activities, inflammatory signaling, and the apoptosis status in duodenum mucosa were investigated. Histological results showed that Se deficiency could increase inflammatory cell infiltration, karyopyknosis of the epithelial cells, cytoplasm vacuolization and dissolution of goblet cells. The proteomics results indicated that Se deficiency could induce apoptosis of cells in duodenal villi via inhibition of antioxidant redox signaling and activation of NF-κB signaling. Further analysis results showed that Se deficiency decreased the total antioxidant capacity of duodenum mucosa via down-regulating the transcription level and activities of glutathione peroxidase (GPX), reduced glutathione (GSH), and thioredoxin reductase (TrxR). The NF-κB signaling pathway was activated by Se deficiency-induced reactive oxygen species (ROS). TUNEL, DNA ladder, immunohistochemical assay, and western blotting proved that selenium deficiency could induce duodenal villi cell apoptosis. The results also indicated that Se deficiency can cause duodenal villi cell apoptosis via an oxidative stress-induced mitochondrial apoptosis pathway (intrinsic pathway) and an inflammatory signaling-induced death receptor pathway (extrinsic pathway). Our data may provide new insight into the prevention and treatment of chronic diarrhea caused by Se deficiency.

Selenium deficiency induces splenic growth retardation by deactivating the IGF-1R/PI3K/Akt/mTOR pathway.

Selenium (Se) deficiency impairs the development and function of immune system in human beings and animals. We investigated the effect and molecular mechanism of Se deficiency on spleen development in chicken. The concentration of Se in blood and spleen, the spleen weight and splenocyte number, the histological characteristics of spleen, the concentration of growth factors in serum, the transcription level of growth factor receptor gene and the activity of growth and proliferation pathway in spleen were investigated. We found that the growth of the spleen and the splenocyte number were significantly lower in the chicken fed with Se-deficient diet for 21 and 35 days. The ELISA and qRT-PCR results showed that the serum IGF-I concentration and the transcription level of IGF1R gene in spleen were significantly lower in the SD group. The Western blotting and immunohistochemistry results showed that Se deficiency could deactivate the PI3K/Akt/mTOR pathway in spleen. In summary, the results indicated that Se deficiency decreases the growth rate of spleen and the number of splenic lymphocytes by deactivating the IGF-1R/PI3K/Akt/mTOR pathway.

17ß-Estradiol and progesterone decrease MDP induced NOD2 expression in bovine mammary epithelial cells.

During the periparturient period, many neuroendocrine changes develop in cows. Periparturient hormone fluxes may adversely affect mammary gland immunity and mastitis susceptibility. 17ß-Estradiol (E2) and progesterone (P4) have been reported to function on immune regulation, and their concentration fluctuates dramatically during the perinatal period. Nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs) mediate numerous aspects of innate immunity in humans and experimental animals. This study aimed to explore the effects of E2 and P4 on NOD2 expression in bovine mammary epithelial cells (BMECs). BMECs were isolated and purified from bovine mammary tissue and treated with E2/P4 and muramyl dipeptide (MDP). After these treatments, the mRNA levels of NOD2, receptor-interacting protein kinase (RIP) 2, interleukin (IL) 1ß, IL-6, IL-8 and tumor necrosis factor (TNF) α were assessed by quantitative real-time polymerase chain reaction (qRT-PCR) respectively, and the protein levels of NOD2 were analyzed by western blotting. The results showed that E2 and P4 decreased MDP-induced transcriptional expression of NOD2 and the downstream molecules. Moreover, E2 reduced MDP-induced NOD2 protein expression levels. Our study suggests that down-regulation of NOD2 by E2 and P4 may be one of the reasons for mastitis susceptibility in periparturient dairy cows.

Application of a microfluidic sperm sorter to in vitro production of dairy cattle sex-sorted embryos.

Viable sperm from sex-sorted semen without centrifugal treatment was separated by a microfluidic sperm sorter (MFSS) for IVF to improve in vitro embryo production of dairy cattle. The MFSS was originally developed to isolate motile human sperm by two laminar flows in the micro-channel (there are four chambers in an MFSS. Chamber A is the inlet for semen, chamber B is the inlet for the medium, chamber C is the exit chamber for motile sperm, and chamber D is the outlet for nonmotile sperm). Sex-sorted sperm were adjusted to 1 × 10(7) spermatozoa/mL (2 million cells/dose, sperm motility was 30% above after thawing). In a first experiment, diluted sex-sorted semen was mixed with modified Medium199(mM199) containing 5-mM caffeine for 5 minutes, resulting in variations in sperm concentration and quality parameters at chambers A, C, and D. In a second experiment, medium containing sperm from three MFSS chambers was collected and mitochondrial activity of the sperm was determined by flow cytometry, the relative activity of sperm mitochondria in chamber C (1.56 ± 0.03) was the highest in three observation areas (P < 0.05). Thus, sperm motility and mitochondrial activity of sperm was high in chamber C. In a third experiment, different concentrations of sperm were added to chamber A and dairy cattle IVM oocytes were placed in chamber C, where motile spermatozoa will accumulate, with mM199 containing 5-mM caffeine for 5 minutes, and then cultured in caffeine-free mM199 for 8 hours. The results showed that sperm penetration rate, the monospermic penetration rate, and blastocyst rate of the 10 × 10(6) group (10 × 10(6) sperm/mL) were higher than in the 1 × 10(6) and 5 × 10(6) groups (P < 0.05). In the last experiment, we compared sperm penetration in the MFSS-IVF system with a modified standard IVF method (cocultured in droplets for 8 hours). The normal fertilization index (the ratio of monospermic oocytes to the number of oocytes examined) 8 hours after insemination was higher in the MFSS-IVF system than the modified standard IVF system (P < 0.05). Developmental competence of fertilized oocytes to the blastocyst stage was also higher in the MFSS-IVF system (40.12% ± 2.61%) than the modified standard IVF technique (24.55% ± 4.54%). These results demonstrate that a short coculture of dairy cattle oocytes with isolated motile sex-sorted spermatozoa gradually accumulated in the MFSS device improves the efficiencies of normally produced fertilized embryos and blastocyst formation.

Low-level laser therapy attenuates LPS-induced rats mastitis by inhibiting polymorphonuclear neutrophil adhesion.

The aim of this study was to investigate the effects of low-level laser therapy (LLLT) on a rat model of lipopolysaccharide (LPS)-induced mastitis and its underlying molecular mechanisms. The rat model of mastitis was induced by inoculation of LPS through the canals of the mammary gland. The results showed that LPS-induced secretion of IL-1ß and IL-8 significantly decreased after LLLT (650 nm, 2.5 mW, 30 mW/cm(2)). LLLT also inhibited intercellular adhesion molecule-1 (ICAM-1) expression and attenuated the LPS-induced decrease of the expression of CD62L and increase of the expression of CD11b. Moreover, LLLT also suppressed LPS-induced polymorphonuclear neutrophils (PMNs) entering the alveoli of the mammary gland. The number of PMNs in the mammary alveolus and the myeloperoxidase (MPO) activity were decreased after LLLT. These results suggested that LLLT therapy is beneficial in decreasing the somatic cell count and improving milk nutritional quality in cows with an intramammary infection.

A polyclonal antibody against the C subunit of porcine aminopeptidase N expressed in Escherichia coli.

The entire pig aminopeptidase N (pAPN) gene was amplified by RT-PCR using total RNA extracted from intestinal brush border membrane of a newborn piglet. The amplified products of the pAPN gene were cloned into the vector pMD18-T, generating a recombinant plasmid pMD18-T-pAPN. The C subunit of pAPN (pAPN-C) produced by PCR from the plasmid pMD18-T-pAPN was expressed in Escherichia coli using vector pET-32a with His tag. After confirming reactivity of the recombinant protein pAPN-C to antibody against native pAPN, polyclonal antibody against the recombinant protein pAPN-C was prepared in rabbit using purified protein as immunogen. In Western blot analysis, the antibody elicited by the recombinant protein pAPN-C could recognize the native pAPN. These data demonstrate that the pAPN-C recombinant protein and its polyclonal antibody can provide some basis for further receptor antagonist.

Development of a novel LAMP diagnostic method for visible detection of swine Pasteurella multocida.

A set of four specific primers for six regions of kmt1 gene from a species specific region was designed for developing the loop-mediated isothermal amplification diagnostic method of swine Pasteurella multocida (Pm-LAMP). After the Pm-LAMP was carried out at 63°C for 1 h, the LAMP products could be visually confirmed using fluorescent dyes as detection reagent under UV-illumination. In sensitivity, the detection limit of the Pm-LAMP was 10 cfu/mL, and was 1 log less than that of the PCR method. In specificity, the Pm-LAMP did not amplify genomic DNA of swine common respiratory pathogens. Furthermore, based on results for clinical swab samples (n = 31) using PCR detection as golden standard, relative sensitivity of the Pm-LAMP was 100%, relative specificity of the Pm-LAMP was 90.9%, and percentage of observation agreement was 93.5% (Kappa = 0.85). The Pm-LAMP method should be a useful diagnostic tool for rapid and visible detection of swine Pasteurella multocida.