O presente trabalho relata um surto de mortalidade de tambacus (Colossoma macropomum x Piaractus mesopotamicus) criados em tanques escavados da Fazenda-Escola da UCDB. Os peixes apresentaram sintomas clínicos de letargia, anorexia, aumento da produção de muco, nado desordenado e comportamento de buscar a superfície da água. Ao exame necroscópico de três peixes foram evidenciadas hemorragias nas nadadeiras e pele, opacidade de córnea, hemoperitôneo, distensão e repleção da vesícula biliar e congestão e hemorragia do tubo digestivo. O exame microbiológico dos materiais coletados das lesões dos tambacus foi positivo para a bactéria Edwardsiella tarda. A análise de qualidade de água indicou grande quantidade de fitoplânctons que proliferaram em função do excesso de matéria orgânica, caracterizando a eutrofização da água. Atribuiu-se a causa da morte dos tambacus à infecção oportunista pela E. tarda, favorecida pelo desequilíbrio devido ao excesso de matéria orgânica em suspensão na água. As mortes cessaram após a correção dos parâmetros da qualidade da água do tanque.

Yersiniosis is a zoonosis causing gastroenteritis, diarrhoea, and occasionally reactive arthritis and septicaemia. Cases are often linked to meat consumption and the most common aetiological agent is the Gram-negative bacilliform Yersinia enterocolitica bacterium. The occurrence of Yersinia spp. among wild animals has mostly been studied in wild boar, but it has seldom been in other species. A total of 1,868 faecal samples from animals found dead or hunted were collected between 2015 and 2018 in the Valle d’Aosta region of the northwestern Italian Alps. Alpine ibex faecal samples were collected during a health monitoring program in 2018. Bacteria were isolated via PCR and confirmed as Y. enterocolitica biochemically. Strain antimicrobial susceptibility was tested by Kirby–Bauer disc diffusion, and the presence of virulence factors and antimicrobial resistance genes was investigated using whole-genome sequencing. Yersinia enterocolitica strains of biotype 1A were detected in six faecal samples from red deer (0.93%), roe deer (0.49%) and red foxes (0.7%). Strains found in beech martens (3.57%) and Alpine ibex (2.77%) belonged to biotypes 1B and 5, respectively and harboured the pYPTS01 plasmid that had only been detected in Y. pseudotuberculosis PB1/+. All the isolates were resistant to ampicillin and erythromycin. The biovar 1A strains exhibited different virulence factors and behaved like non-pathogenic commensals. The strain from an Alpine ibex also harboured the self-transmissible pYE854 plasmid that can mobilise itself and the pYPTS01 plasmid to other strains. The beech marten could be considered a sentinel animal for Y. enterocolitica. Phenotypic resistance may account for the ability of all the strains to resist β-lactams.

Salmonella enterica serotype Choleraesuis causes swine paratyphoid, with clinical findings of enterocolitis and septicemia. However, the clinicopathological features of S. Choleraesuis infections in pigs have not been reported in Korea. We describe the pathological findings of two weaned pigs with S. Choleraesuis infections, presenting with diarrhea, cough, and sudden death. Pathological examination indicated severe necrotic colitis in pig 1 and septicemic lesions in pig 2. Multidrug-resistant S. Choleraesuis was isolated from the pigs’ lungs and intestinal contents. Further research is required for the surveillance of S. Choleraesuis infections in pigs and the virulence estimation in the S. Choleraesuis isolates.

This study describes the macroscopic and microscopic lesions in farmed rainbow trout (Oncorhynchus mykiss) naturally infected with genetically identified Aeromonas salmonicida, A. hydrophila, and A. veronii species. The genus Aeromonas includes bacteria that naturally inhabit both waterways and organisms. At least 27 Aeromonas species have been identified to date, some of which can cause significant economic losses in aquaculture. As up to 68.8% of Aeromonas isolates may be misidentified in routine biochemical and phenotypic tests, however, reported cases of Aeromonas infection in fish may be wrongly identified. Our findings confirmed that the 3 Aeromonas species studied are associated with septicemia and dermal lesions in rainbow trout.

Aeromonas hydrophilia infection was diagnosed in captive Jackass penguins (Spheniscus demersus). Seven Jackass penguins showed clinical signs including depression and anorexia with greenish vomiting, but four penguins were died although extensive treatment was carried out. At necropsy, the penguins appeared to have hemorrhage and catarrhal inflammation of the small and large intestines and severe enlargement of the right hepatic lobe, elongation of the gall bladder and pyloric ulceration of the stomach. The ovaries observed atrophy and congestion. Microscopically, there were congestion, fat droplet within the cytoplasm of the hepatic cell, infiltration of lymphocytes in the stomach, vilous detachment and destroyed glandular epithelium in the small and large intestines.

Concentrations of amino acids in the plasma of 13 neonatal foals with septicemia were compared with the concentrations of amino acids in the plasma of 13 age-matched neonatal foals without septicemia. Analysis of the results revealed significantly lower concentrations of arginine, citrulline, isoleucine, proline, threonine, and valine in the plasma of foals with septicemia. The ratio of the plasma concentrations of the branched chain amino acids (isoleucine, leucine, and valine) to the aromatic amino acids (phenylalanine and tyrosine), was also significantly lower in the foals with septicemia. In addition, the concentrations of alanine, glycine, and phenylalanine were significantly higher in the plasma of foals with septicemia. Therefore, neonatal foals with septicemia had significant differences in the concentrations of several amino acids in their plasma, compared with concentrations from healthy foals. These differences were compatible with protein calorie inadequacy and may be related to an alteration in the intake, production, use, or clearance of amino acids from the plasma pool in sepsis.

Twenty-nine healthy 17- to 29-day-old unweaned Isaeli-Friesian male calves were each given a single IV or IM injection of 10 or 20 mg of moxalactam disodium/kg of body weight. Serum concentrations were measured serially during a 12-hour period. Serum concentration vs time profiles were analyzed by use of linear least-squares regression analysis and the statistical moment theory. The elimination half-lives after IV administration were 143.7 +/- 30.2 minutes and 155.5 +/- 10.5 minutes (harmonic mean +/ SD) at dosages of 10 and 20 mg of moxalactam/kg of body weight, respectively. Corresponding mean residence time values were 153.1 +/- 26.8 minutes and 169.9 +/- 19.3 minutes (arithmetic mean +/- SD). Mean residence time values after IM administration were 200.4 +/- 17.5 minutes and 198.4 +/- 19.9 minutes at dosages of 10 and 20 mg/kg, respectively. The volumes of distribution at steady state were 0.285 +/- 0.073 L/kg and 0.313 +/- 0.020 L/kg and total body clearance values were 1.96 +/- 0.69 ml/min/kg and 1.86 +/- 0.18 ml/min/kg after administration of dosages of 10 and 20 mg/kg, respectively. Moxalactam was rapidly absorbed from the IM injection site and peak serum concentrations occurred at 1 hour. The estimated bioavailability ranged from 69.8 to 79.1%. The amount of serum protein binding was 53.4, 55.0, and 61.5% when a concentration of moxalactam was at 50, 10, and 2 micrograms/ml respectively. The minimal inhibitory concentrations of moxalactam ranged from 0.01 to 0.2 micrograms/ml against Salmonella and Escherichia coli strains and from 0.005 to 6.25 micrograms/ml against Pasteurella multocida strains.

Streptococcus suis is an emerging zoonotic pathogen that causes septicemia, meningitis, arthritis, and pneumonia in swine and humans. The present study aimed to characterize the genetic diversity of S. suis serotype 2 isolated from pigs showing signs of illness in Brazil using pulsed-field gel electrophoresis (PFGE), single-enzyme amplified fragment length polymorphism (SE-AFLP), and profiling of virulence-associated markers. A total of 110 isolates were studied, 62.7% of which were isolated from the central nervous system and 19.1% from the respiratory tract. Eight genotypes were obtained from the combination of virulence genes, with 43.6% and 5.5% frequencies for the mrp (+) /epf (+) /sly (+) and mrp (-) /epf (-) /sly (-) genotypes, respectively. The presence of isolates with epf gene variation with higher molecular weight also appears to be a characteristic of Brazilian S. suis serotype 2. The PFGE and SE-AFLP were able to type all isolates and, although they presented a slight tendency to cluster according to state and year of isolation, it was also evident the grouping of different herds in the same PFGE subtype and the existence of isolates originated from the same herd classified into distinct subtypes. No further correlation between the isolation sites and mrp/epf/sly genotypes was observed.

This study established a disease model and protocol for bacterial challenge with Escherichia coli serogroup O2 strain EC317 in Japanese quail. Five groups of 10 birds each were injected subcutaneously in the breast with 200 μL of a brain–heart infusion (BHI) culture containing 1 × 10(8), 1 × 10(7), 1 × 10(6), 1 × 10(5), or 1 × 10(4) colony-forming units/mL of the test organism, which had been isolated from a turkey with cellulitis and septicemia. Birds in a 6th group were controls that received sterile BHI alone. Localized lesions of cellulitis developed in all of the birds that received E. coli. The morbidity and mortality rates were highest (100%) in the birds receiving the highest dose of E. coli and decreased linearly with decreasing dose (P < 0.05). Severity of disease, including lesions of pericarditis and perihepatitis, was also directly proportional to the dose of E. coli. These findings indicate that this disease challenge protocol can be used to study disease resistance and immunologic consequences of contaminant exposure or other stressors in birds.