Frequency of Detection of Escherichia coli, Salmonella spp., and Campylobacter spp. in the Faeces of Wild Rats (Rattus spp.) in Trinidad and Tobago

The study was conducted to determine the frequency of isolation of Salmonella, Campylobacter and E. coli O157 in the faecal samples of rats trapped across the regional corporations in Trinidad and to assess their resistance to antimicrobial agents. A total of 204 rats were trapped for the detection of selected bacteria. Standard methods were used to isolate Salmonella, Campylobacter and E. coli O157. Characterization of E. coli was done on sorbitol MacConkey agar to determine non-sorbitol fermentation, blood agar to determine haemolytic and mucoid colonies and by using E. coli O157 antiserum to determine O157 strain. The disc diffusion method was used to determine resistance to nine antimicrobial agents. Of the 204 rats, 4 (2.0%), 7 (3.4%) and 171 (83.8%) were positive for Salmonella spp., Campylobacter spp. and E. coli, respectively. Of the 171 isolates of E. coli tested 0 (0.0%), 25 (14.6%) and 19 (11.1%) were haemolytic, mucoid and non-sorbitol fermenters, respectively. All isolates were negative for the O157 strain. The frequency of resistance to the 9 antimicrobial agents tested was 75% (3 of 4) for Salmonella, 85.7% (6 of 7) of Campylobacter spp. and 36.3% (62 of 171) for E. coli (P < .05; χ2)

Immune response at a vaccine-challenge study using beagle dogs and locally isolated Leptospira spp

Determination of the immune response of dogs by measuring the antibody levels (utilizing MAT) and levels of cytokines (TNF-α, IL-4 and IFN-γ) post-vaccination with locally produced killed whole-celled Leptospiral vaccine and post-challenge with a locally isolated Leptospira icterohaemorrhagiae Copenhageni strain. For assessment of immunity of the vaccine serum antibodies were detected before and after vaccination and challenge in three studies. The effects of the challenge were determined by a variety of parameters including reisolation of the challenge Leptospira spp. via blood, urine, and kidney samples. The challenge strain did not produce generalised infection but elevated circulating antibody levels in both the control and vaccinated dogs in any of the three studies, however leptospires were reisolated from the urine of the control dogs but not the vaccinated dogs. Cytokine levels (TNF-α, IFN-γ and IL-4) were detected post-challenge in the vaccinated dogs to determine the immune profile response. The whole-killed cell vaccine in this study did not prevent leptospireamia but prevented leptospiruria in vaccinated dogs after a challenge with a live Leptospira icterohaemorrhagiea Copenhageni. The vaccine-challenge showed increased antibody (MAT) levels due to vaccination and infection (through challenge). Cytokine production (TNF-α, IFN-γ and IL-4) by the host immune system was observed post-challenge with live leptospires.https://www.elsevier.com/locate/vetimmhj2023Production Animal Studie

Antimicrobial susceptibility of Leptospira isolates from dogs and rats to 12 antimicrobial agents

Abstract. This study determined the antimicrobial susceptibilities of 67 isolates of Leptospira from dogs (suspect canine cases: n=7 and stray dogs: n=6) and rodents (n=54) in Trinidad to 12 antimicrobial agents using broth microdilution and macrodilution techniques. Commonly used antimicrobial agents such as the penicillin G and ceftriaxone had relatively low minimal inhibitory concentrations (MICs) while doxycycline displayed a relatively higher value but was still considered to be effective. While imipenem was the most effective with low MIC values in vitro, sulphamethoxazole-trimethoprim had the highest i.e. least effective. Based on these results, the drugs commonly used in the treatment of leptospirosis (penicillin G, penicillin-streptomycin, doxycycline and ceftriaxone) in both humans and animals in Trinidad appear to have similar MICs and MBCs in vitro when compared with published reports. The serovar of Leptospira spp. and in most cases the origin of the isolates did not significantly (P&gt;0.05) influence their susceptibilities to the antimicrobial agents tested

Mitral kissing vegetation and acquired aortic valve stenosis secondary to infectious endocarditis in a goat with suppurative mastitis

A six-year-old female goat was presented to the veterinary teaching hospital of the University of the West Indies with a history of progressive hind-limb paresis lasting two weeks. The doe developed a grade 6/6 holosystolic murmur during hospitalisation. Echocardiography revealed vegetative growths attached to cusps of the mitral and aortic valves. Therewas an accelerated aortic flow at 2.9 m/s and aortic insufficiency. The aortic vegetation was prolapsing into the left ventricle during diastole, causing it to contact the septal mitral valve leaflet. A diagnosis of mitral and aortic vegetative endocarditis, with a mitral kissing vegetation and mild aortic stenosis, was reached. The patient was placed on broad-spectrum antimicrobials. A short-term follow-up showed no resolution of clinical signs, and the animal eventually died. Post-mortem examination showed severe vegetative, fibrino-necrotic, aortic and mitral valve lesions. The goat also had a severe fibrino-suppurative mastitis. Histopathology confirmed the lesions to be vegetative endocarditis

Benchmark Acetylene Binding Affinity and Separation through Induced Fit in a Flexible Hybrid Ultramicroporous Material

Structural changes at the active site of an enzyme induced by binding to a substrate molecule can result in enhanced activity in biological systems. Herein, we report that the new hybrid ultramicroporous material sql-SIFSIX-bpe-Zn exhibits an induced fit binding mechanism when exposed to acetylene, C₂H₂. The resulting phase change affords exceptionally strong C₂H₂ binding that in turn enables highly selective C₂H₂/C₂H₄ and C₂H₂/CO₂ separation demonstrated by dynamic breakthrough experiments. sql-SIFSIX-bpe-Zn was observed to exhibit at least four phases: as-synthesised (α); activated (β); and C₂H₂ induced phases (β' and γ). sql-SIFSIX-bpe-Zn-β exhibited strong affinity for C₂H₂ at ambient conditions as demonstrated by benchmark isosteric heat of adsorption (Qst ) of 67.5 kJ mol⁻¹ validated through in situ pressure gradient differential scanning calorimetry (PG-DSC). Further, in situ characterisation and DFT calculations provide insight into the mechanism of the C₂H₂ induced fit transformation, binding positions and the nature of host-guest and guest-guest interactions

Simulations of H2 Sorption in Metal-Organic Frameworks

Metal-organic frameworks are a diverse group of crystalline materials consisting of metal ionscoordinated to organic ligands. Their characteristic high porosity, large surface area along with tunable pore structures and chemical functionalities make them an exceptional candidate for H2 storage applications. Computational studies of H2 sorption in metal-organic frameworks aid in producing molecular-level insights which can facilitate the design of structures with improved performance. In this work, various MOFs were investigated using grand canonical Monte Carlo simulations. Addressed first are two MOFs with rht topologies which consist of two chemically distinct Cu2+ ions coordinated to triisophthalate ligands. Through electronic structure calculations and classical simulations it was revealed that minor modifications to the ligand that are not in close proximity to the open metal sites led to drastic differences in the charge distribution within the copper paddlewheel and affect which metal site would be preferred for sorption. Furthermore, it was found that minor modifications to the ligand have the potential to create additional sorption sites which are not present in prototypical structures and can also give rise to enhanced heat of sorption for H2. The final chapter focuses on a MOF system with a highly asymmetrical structure whereby the metal ions are coordinated to two types of ligand in a distorted octahedral fashion. This chapter provides a comparison of two different metal analogues (Mg2+ and Co2+) , highlighting their interchangeability and also providing insights into favored sorption sites in this type of system

Simulations of H2 Sorption in Metal-Organic Frameworks

Metal-organic frameworks are a diverse group of crystalline materials consisting of metal ionscoordinated to organic ligands. Their characteristic high porosity, large surface area along with tunable pore structures and chemical functionalities make them an exceptional candidate for H2 storage applications. Computational studies of H2 sorption in metal-organic frameworks aid in producing molecular-level insights which can facilitate the design of structures with improved performance. In this work, various MOFs were investigated using grand canonical Monte Carlo simulations. Addressed first are two MOFs with rht topologies which consist of two chemically distinct Cu2+ ions coordinated to triisophthalate ligands. Through electronic structure calculations and classical simulations it was revealed that minor modifications to the ligand that are not in close proximity to the open metal sites led to drastic differences in the charge distribution within the copper paddlewheel and affect which metal site would be preferred for sorption. Furthermore, it was found that minor modifications to the ligand have the potential to create additional sorption sites which are not present in prototypical structures and can also give rise to enhanced heat of sorption for H2. The final chapter focuses on a MOF system with a highly asymmetrical structure whereby the metal ions are coordinated to two types of ligand in a distorted octahedral fashion. This chapter provides a comparison of two different metal analogues (Mg2+ and Co2+) , highlighting their interchangeability and also providing insights into favored sorption sites in this type of system

Oral Plasmacytoma in a Dog

A 6-year-old male Pit bull mix dog presented for bleeding from the mouth persisting for five days. A clinical evaluation revealed a 2 × 3 cm soft tissue mandibular mass at the crown of the first premolar, as well as a non-regenerative anemia and hyperproteinemia. Cytologic and histopathologic evaluations of the mass were compatible with an oral plasmacytoma

Serological Evidence of Exposure to Leptospira spp. in Veterinary Students and Other University Students in Trinidad and Tobago

The study compared the serological evidence of leptospirosis in 212 students in four schools (veterinary, dental, advanced nursing education and pharmacy) of the University of the West Indies (UWI), by testing for IgG immunoglobulins to Leptospira spp. using the enzyme-linked immunosorbent assay (ELISA) and the microscopic agglutination test (MAT). Overall, of 212 students tested by the ELISA, 12 (5.7%) and 31 (14.6%) were positive and borderline, respectively. Amongst the 113 veterinary students 11 (9.7%) and 19 (16.8%) were seropositive and borderline respectively compared with nonveterinary students with corresponding values of 1 (1.0%) and 12 (12.1%). The frequency of serological evidence of leptospirosis by the ELISA was statistically significantly (; ) higher in veterinary students, 26.5% (30 of 113) than in nonveterinary students, 13.1% (13 of 99). By the MAT, the seropositivity for leptospirosis was similar for veterinary students, 7.1% (8 of 113) and nonveterinary students, 7.1% (7 of 99). For veterinary students, the prevalent infecting serovar was Icterohaemorrhagiae Copenhageni while amongst nonveterinary students, the prevalent serovar was Australis Rachmati. Being a veterinary student was the only risk factor that was significantly associated with Leptospira infection indicating that veterinary students need to be cognizant and to practise preventive measures for leptospirosis