Bordetella bronchiseptica: A Candidate Mucosal Vaccine Vector

Bordetella bronchiseptica colonizes the upper respiratory tract of a wide variety of mammals and is involved in diseases such as kennel cough in dogs, atrophic rhinitis in pigs and upper respiratory tract infections of laboratory animals. Studies were focused on developing a heterologous antigen expression system in B. bronchiseptica and to evaluate the potential of this organism as a candidate mucosal vaccine vector. Since the role of Bordetella bronchiseptica and Pasteurella multocida toxin (PMT) in the disease atrophic rhinitis of pigs was well documented, this research was focused in the possibility of developing a refined vaccine to control this disease. A promoter region related to heat shock protein genes was identified using a green fluorescent protein reporter system. This promoter drove high- level expression of GFP compared to a tac promoter or B. bronchiseptica fim N gene promoter. A nontoxic protective P. multocida toxin fragment and GFP were expressed in B.bronchiseptica in a broad-host-range plasmid vector PBBR1MCS2 under the control of the promoter region identified. Colonization kinetics, plasmid stability, and immune responses generated following intranasal inoculation of recombinant B. bronchiseptica were evaluated. While wild type and recombinant B. bronchiseptica colonized the mouse respiratory tract effectively, the plasmid was completely lost from the organism after 72 hours post- inoculation. After a single intranasal inoculation, B. bronchiseptica specific IgM, IgA and IgG responses were detected in serum and respiratory lavage. However, PMT-specific antibodies were not detected. Four intranasal inoculations with B. bronchiseptica expressing green fluorescent protein (GFP) induced a GFP-specific systemic and mucosal immune response, while similar inoculations with B. bronchiseptica expressing PMT fragment did not induce a PMT-specific immune response. This study also evaluated the immune response to a chimeric protein generated by combining a gene fragment encoding neutralizing epitopes of Mannheimia haemolytica leukotoxin and a fimbrial protein gene (fim N) from B. bronchiseptica. Immunization of mice with the recombinant chimeric protein elicited a significantly stronger anti-leukotoxin antibody response than comparable immunizations with fusion proteins lacking FIM N. The chimeric protein exhibited more stability. Leukotoxin is an important virulence factor in shipping fever pneumonia in feedlot cattle and is a critical protective antigen. This chimeric protein may be a candidate for inclusion in new generation vaccines against shipping fever pneumonia. The results of these studies strongly support the potential for developing B. bronchiseptica as a candidate mucosal vaccine vector and FIM N as a carrier protein for heterologous antigens

First Whole Genome Sequence of Anaplasma platys, an Obligate Intracellula Rickettsial Pathogen of Dogs

We have assembled the first genome draft of Anaplasma platys, an obligate intracellular rickettsia, and the only known bacterial pathogen infecting canine platelets. A. platys is a not-yet-cultivated bacterium that causes infectious cyclic canine thrombocytopenia, a potentially fatal disease in dogs. Despite its global distribution and veterinary relevance, no genome sequence has been published so far for this pathogen. Here, we used a strategy based on metagenome assembly to generate a draft of the A. platys genome using the blood of an infected dog. The assembled draft is similar to other Anaplasma genomes in size, gene content, and synteny. Notable differences are the apparent absence of rbfA, a gene encoding a 30S ribosome-binding factor acting as a cold-shock protein, as well as two genes involved in biotin metabolism. We also observed differences associated with expanded gene families, including those encoding outer membrane proteins, a type IV secretion system, ankyrin repeat-containing proteins, and proteins with predicted intrinsically disordered regions. Several of these families have members highly divergent in sequence, likely to be associated with survival and interactions within the host and the vector. The sequence of the A. platys genome can benefit future studies regarding invasion, survival, and pathogenesis of Anaplasma species, while paving the way for the better design of treatment and prevention strategies against these neglected intracellular pathogens.We have assembled the first genome draft of Anaplasma platys, an obligate intracellular rickettsia, and the only known bacterial pathogen infecting canine platelets. A. platys is a not-yet-cultivated bacterium that causes infectious cyclic canine thrombocytopenia, a potentially fatal disease in dogs. Despite its global distribution and veterinary relevance, no genome sequence has been published so far for this pathogen. Here, we used a strategy based on metagenome assembly to generate a draft of the A. platys genome using the blood of an infected dog. The assembled draft is similar to other Anaplasma genomes in size, gene content, and synteny. Notable differences are the apparent absence of rbfA, a gene encoding a 30S ribosome-binding factor acting as a cold-shock protein, as well as two genes involved in biotin metabolism. We also observed differences associated with expanded gene families, including those encoding outer membrane proteins, a type IV secretion system, ankyrin repeat-containing proteins, and proteins with predicted intrinsically disordered regions. Several of these families have members highly divergent in sequence, likely to be associated with survival and interactions within the host and the vector. The sequence of the A. platys genome can benefit future studies regarding invasion, survival, and pathogenesis of Anaplasma species, while paving the way for the better design of treatment and prevention strategies against these neglected intracellular pathogens

Diagnosis of pancreatic disease in feline platynosomosis

Objectives: Platynosomum species are cat-specific parasitic trematodes that parasitize the biliary ducts and gall bladder. Due to the common connection to the major duodenal papilla of the pancreas and common bile ducts in addition to the periductal proximity of the pancreas, it is possible that platynosomosis could cause pancreatitis. The objective of this study was to determine whether platynosomosis, a commonly diagnosed parasitic disease in cats on St Kitts, has any association with pancreatic disease. Methods: To investigate this possibility, the pancreas of free-roaming cats with naturally acquired platynosomosis were evaluated via ultrasound, serum concentrations of feline pancreatic lipase (fPL), cobalamin, folate and feline trypsin-like immunoreactivity (fTLI) and histopathology. Twenty free-roaming, young adult, feral cats, positive for feline immunodeficiency virus, and diagnosed with Platynosomum species infection via fecal analysis were recruited. The liver, biliary system and pancreas were evaluated via ultrasonography during a short duration anesthesia. Serum concentrations of fPL, fTLI, folate and cobalamin were measured. Sections of the right limb, left limb and body of the pancreas were evaluated histopathologically using hematoxylin and eosin (H&E) stain. Results: None of the cats had sufficient criteria to fulfill the ultrasonographic diagnosis of pancreatitis. One cat had an elevated fPL concentration in the range consistent with pancreatitis. Four cats had cobalamin deficiencies and 11 had abnormal folate concentration. The fTLI concentration was equivocal for the diagnosis of exocrine pancreatic insufficiency in one cat. With a single exception, histopathology changes, when present (n = 12), were mild, non-specific and predominantly characterized by lymphocytic infiltrates and fibrosis. The exception was a cat that presented a chronic interstitial and eosinophilic pancreatitis of slightly increased severity, likely the result of platynosomosis. Conclusions and relevance: The results of this study suggest that platynosomosis rarely induces pancreatic damage in cats. With only one exception, chronic pancreatitis diagnosed in cats with fluke-induced cholangitis and cholangiohepatitis was subtle and interpreted as an incidental background lesion unrelated to platynosomosis

Complete Genome Sequence of a Virulent Leptospira interrogans Serovar Copenhageni Strain, Assembled with a Combination of Nanopore and Illumina Reads

Here, we present the complete genome sequence of a highly virulent Leptospira interrogans serovar Copenhageni strain isolated from a dog with severe leptospirosis. In this work, a gapless genome draft was assembled with a combination of Nanopore and Illumina data of relatively low coverage.Here, we present the complete genome sequence of a highly virulent Leptospira interrogans serovar Copenhageni strain isolated from a dog with severe leptospirosis. In this work, a gapless genome draft was assembled with a combination of Nanopore and Illumina data of relatively low coverage

Detection and Characterization of Leptospira Infection and Exposure in Rats on the Caribbean Island of Saint Kitts

In this study, we detected and characterized Leptospira infection and exposure in rats on the Caribbean island of Saint Kitts for the first time. We detected Leptospira infection in 17/29 (59%), 14/29 (48) %, and 11/29 (38) % of rats by RT-PCR, culture, and immunofluorescence assay, respectively. Whole genome sequencing (WGS) and analysis and serogrouping of 17 Leptospira strains isolated from rats revealed their close relationship with L. interrogans serogroup Icterohaemorrhagiae (n = 10) and L. borgpetersenii serogroup Ballum (n = 7). WGS, serogrouping, and additional PCR tests on rat kidneys confirmed mixed infections with L. interrogans and L. borgpetersenii in the kidneys of three rats. Microscopic agglutination test (MAT) was positive for 25/29 (87%) of the rats tested, and the response was restricted to serovars Icterohaemorrhagiae {24/29(83%)}, Mankarso {4/29(14%)}, Copenhageni {4/29(14%)}, Grippotyphosa {2/29(7%)}, and Wolffi {1/29(3%)}. Interestingly, there was no agglutinating antibody response to serovar Ballum. We observed a similar pattern in the serologic response using Leptospira isolates obtained from this study with each of the rat sera, with strong response to L. interrogans isolates but minimal reactivity to L. borgpetersenii isolates. Our findings suggest the use of multiple complementary diagnostic tests for Leptospira surveillance and diagnosis to improve the accuracy of the dataIn this study, we detected and characterized Leptospira infection and exposure in rats on the Caribbean island of Saint Kitts for the first time. We detected Leptospira infection in 17/29 (59%), 14/29 (48) %, and 11/29 (38) % of rats by RT-PCR, culture, and immunofluorescence assay, respectively. Whole genome sequencing (WGS) and analysis and serogrouping of 17 Leptospira strains isolated from rats revealed their close relationship with L. interrogans serogroup Icterohaemorrhagiae (n = 10) and L. borgpetersenii serogroup Ballum (n = 7). WGS, serogrouping, and additional PCR tests on rat kidneys confirmed mixed infections with L. interrogans and L. borgpetersenii in the kidneys of three rats. Microscopic agglutination test (MAT) was positive for 25/29 (87%) of the rats tested, and the response was restricted to serovars Icterohaemorrhagiae {24/29(83%)}, Mankarso {4/29(14%)}, Copenhageni {4/29(14%)}, Grippotyphosa {2/29(7%)}, and Wolffi {1/29(3%)}. Interestingly, there was no agglutinating antibody response to serovar Ballum. We observed a similar pattern in the serologic response using Leptospira isolates obtained from this study with each of the rat sera, with strong response to L. interrogans isolates but minimal reactivity to L. borgpetersenii isolates. Our findings suggest the use of multiple complementary diagnostic tests for Leptospira surveillance and diagnosis to improve the accuracy of the dat

Betacoronavirus genomes: How genomic information has been used to deal with past outbreaks and the COVID-19 pandemic

In the 21st century, three highly pathogenic betacoronaviruses have emerged, with an alarming rate of human morbidity and case fatality. Genomic information has been widely used to understand the pathogenesis, animal origin and mode of transmission of betacoronaviruses in the aftermath of the 2002-03 severe acute respiratory syndrome (SARS) and 2012 Middle East respiratory syndrome (MERS) outbreaks. Furthermore, genome sequencing and bioinformatic analysis have had an unprecedented relevance in the battle against the 2019-20 coronavirus disease 2019 (COVID-19) pandemic, the newest and most devastating outbreak caused by a coronavirus in the history of mankind, allowing the follow up of disease spread and transmission dynamics in near real time. Here, we review how genomic information has been used to tackle outbreaks caused by emerging, highly pathogenic, betacoronavirus strains, emphasizing on SARS-CoV, MERS-CoV and SARS-CoV-2.In the 21st century, three highly pathogenic betacoronaviruses have emerged, with an alarming rate of human morbidity and case fatality. Genomic information has been widely used to understand the pathogenesis, animal origin and mode of transmission of betacoronaviruses in the aftermath of the 2002-03 severe acute respiratory syndrome (SARS) and 2012 Middle East respiratory syndrome (MERS) outbreaks. Furthermore, genome sequencing and bioinformatic analysis have had an unprecedented relevance in the battle against the 2019-20 coronavirus disease 2019 (COVID-19) pandemic, the newest and most devastating outbreak caused by a coronavirus in the history of mankind, allowing the follow up of disease spread and transmission dynamics in near real time. Here, we review how genomic information has been used to tackle outbreaks caused by emerging, highly pathogenic, betacoronavirus strains, emphasizing on SARS-CoV, MERS-CoV and SARS-CoV-2

In vitro and in vivo assessment of caprine origin Staphylococcus aureus ST398 strain UTCVM1 as an osteomyelitis pathogen

Staphylococcus aureus (SA) is a significant and well-recognized causative organism of bacterial osteomyelitis. Osteomyelitis is an inflammatory bone disease characterized by progressive bone destruction and loss. This disease causes significant morbidity and mortality to the patient and poses therapeutic challenges for clinicians. To improve the efficacy of therapeutic strategies to combat bacterial osteomyelitis, there is a need to define the molecular epidemiology of bacterial organisms more clearly and further the understanding of the pathogenesis of SA osteomyelitis. We conducted in vitro characterization of the pathogenic capabilities of an isolate of SA ST398 derived from a clinical case of osteomyelitis in a goat. We also report a rodent mandibular defect model to determine the ability of ST398 to cause reproducible osteomyelitis. Our results indicate that ST398 can invade and distort pre-osteoblastic cells in culture, induce significant inflammation and alter expression of osteoregulatory cytokines. We also demonstrate the ability of ST398 to induce osteomyelitis in a rat mandibular model. When compiled, these data support ST398 as a competent osteomyelitis pathogen