The detection and recovery of Erysipelothrix spp. in meat and abattoir samples in Western Australia

Erysipelothrix Spp.: Past, Present, and Future Directions in Vaccine Research

Erysipelothrix spp. comprise a group of small Gram-positive bacteria that can infect a variety of hosts including mammals, fish, birds, reptiles and insects. Among the eight Erysipelothrix species that have been described to date, only Erysipelothrix rhusiopathiae plays a major role in farmed livestock where it is the causative agent of erysipelas. E. rhusiopathiae also has zoonotic potential and can cause erysipeloid in humans with a clear occupational link to meat and fish industries. While there are 28 known Erysipelothrix serovars, over 80% of identified isolates belong to serovars 1 or 2. Vaccines to protect pigs against E. rhusiopathiae first became available in 1883 as a response to an epizootic of swine erysipelas in southern France. The overall vaccine repertoire was notably enlarged between the 1940s and 1960s following major outbreaks of swine erysipelas in the Midwest USA and has changed little since. Traditionally, E. rhusiopathiae serovar 1a or 2 isolates were inactivated (bacterins) or attenuated and these types of vaccines are still used today on a global basis. E. rhusiopathiae vaccines are most commonly used in pigs, poultry, and sheep where the bacterium can cause considerable economic losses. In addition, erysipelas vaccination is also utilized in selected vulnerable susceptible populations, such as marine mammals in aquariums, which are commonly vaccinated at regular intervals. While commercially produced erysipelas vaccines appear to provide good protection against clinical disease, in recent years there has been an increase in perceived vaccine failures in farmed animals, especially in organic outdoor operations. Moreover, clinical erysipelas outbreaks have been reported in animal populations not previously considered at risk. This has raised concerns over a possible lack of vaccine protection across various production species. This review focuses on summarizing the history and the present status of E. rhusiopathiae vaccines, the current knowledge on protection including surface antigens, and also provides an outlook into future directions for vaccine development.

Erysipelothrix Septicaemia and Hepatitis in a Colony of Humboldt Penguins (Spheniscus humboldti)

This report describes an outbreak of erysipelas in a colony of captive Humboldt penguins (Spheniscus humboldti). The only previously reported case in a related species was of an individual little blue penguin (Eudyptula minor). Five Humboldt penguins in a mixed colony displayed non-specific signs of illness, including lethargy, inappetence and regurgitation after movement for exhibit upgrading. There was no improvement after 5 days of treatment with oral enrofloxacin (10 mg/kg q24h). Four Humboldt penguins, including two that were not part of the original five displaying signs of illness, died during this outbreak and Erysipelothrix rhusiopathiae was cultured from organ samples collected post mortem. Oral clavulanic acid/amoxycillin (125 mg/kg q12h) was added to the treatment of the sick Humboldt penguins, as well as itraconazole (8.5 mg/kg q12h) and silymarin (10 mg/kg q24h) for 10 days (both per os), which resolved their clinical signs. The likely source of E. rhusiopathiae was the fish they were fed, but this could not be confirmed. Another contributing factor to the growth of E. rhusiopathiae in the exhibit pool was the increase in water temperature due to a fault in the water circulating system. The temperature of the pool water had increased to 29°C, which was rectified, and the water temperature decreased to 13°C. However, there was one further Humboldt penguin death after the decrease in water temperature. This episode suggests that E. rhusiopathiae infection should be high on the differential list of piscivorous avian species with non-specific clinical signs. A liver biopsy for bacterial culture and sensitivity may be required for definitive diagnosis.

Incision of the heart during meat inspection of fattening pigs - A risk-profile approach

Meat inspection in the EU is based on Regulation (EC) 854/2004. Accordingly a risk based meat inspection should be implemented. In this paper, the incision of the heart in pig meat inspection is discussed with respect to efficacy. The incision especially can reveal the presence of endocarditis. Here, Erysipelothrixrhusiopathiae (E. rhusiopathiae) and/or Streptococcussuis (S. suis) are of particular concern. Both agents are regarded to be zoonotic agents. There is some evidence for infection of humans via an alimentary pathway. Hence, the occurrence of E. rhusiopathiae and S. suis is a concern of public health (PH) as well as veterinary public health (VPH). However, other measures, including on-farm disease prevention and diagnosis, seem to be more important for food safety. It is concluded that the incision and inspection of the heart is not justifiable with respect to PH aspects.

Neuraminidase production by Erysipelothrix rhusiopathiae

In order to characterise neuraminidase activity by Erysipelothrix, 85 isolates of Erysipelothrix spp. from a variety of sources including human clinical, marine and terrestrial animals, and the environment were investigated for neuraminidase production. Neuraminidase activity was detected by a peanut lectin haemagglutination method. The effects of media, incubation conditions and pH on the production and activity of neuraminidase were also investigated. Enzyme activity was detected only in the supernatants of the isolates of Erysipelothrix rhusiopathiae which had been incubated in cooked meat broth and Todd Hewitt broth supplemented with horse serum after 16 and 36 h incubation at 37 degrees C. The maximum titres were reached at 40 h in cooked meat broth and 56 h in Todd Hewitt broth supplemented with horse serum. All 58 isolates and the type strain (ATCC 19414) of E. rhusiopathiae produced detectable neuraminidase activity with titres between 10 and 320. The optimal pH for the enzyme activity varied among the isolates with a pH between 6.0 and 7.0 covering the highest enzyme activity of the most. There was no statistically significant difference in the level of neuraminidase activity between isolates from different sources (p > 0.05). Neuraminidase activity was not detected in the non-pathogenic Erysipelothrix spp. such as E. tonsillarum. Neuraminidase was detected only in E. rhusiopathiae suggesting its possible role as a virulence factor. Enzyme production and activity were medium and pH dependent. The peanut lectin haemagglutination assay is a simple, rapid and sensitive method and is particularly useful for the analysis of multiple samples.