Characterization ofErysipelothrix rhusiopathiaeisolates from laying hens and poultry red mites (Dermanyssus gallinae) from an outbreak of erysipelas

Abstract

Infection with the zoonotic bacterium Erysipelothrix rhusiopathiae causes severe disease outbreaks (erysipelas) in poultry flocks. As this bacterium has been isolated from the poultry red mite (Dermanyssus gallinae), this parasite has been suggested as a possible means of transmission of E. rhusiopathiae on and between poultry farms. To further elucidate the capacity of the mite as a reservoir, we analysed and compared 56 bacterial isolates from laying hens and nine isolates from mites by pulsed-field gel electrophoresis (PFGE), using the restriction enzyme SmaI. The isolates originated from one outbreak in a laying hen flock housed in an indoor litter-based aviary system. Except for two isolates, a homogeneous banding pattern was obtained from all isolates analysed, suggesting that a single strain was the cause of the outbreak. Another finding was that isolates from individual hens could exhibit slightly different PFGE patterns. Mites collected from the same house at the end of the production period of the following flock were negative for the presence of E. rhusiopathiae. An increasing number of erysipelas outbreaks as well as escalating problems with D. gallinae are expected in other European countries related to the forthcoming changes in housing systems for laying hens. Consequently, further studies are needed to investigate the importance of erysipelas in poultry and the importance of D. gallinae in the transmission of E. rhusiopathiae.

Erysipelothrix rhusiopathiaecontamination in the poultry house environment during erysipelas outbreaks in organic laying hen flocks

“…This could be explained by the limited number of samples or contamination of the manure heap from an external source. Another possibility is that the flock was infected by two distinctly different PFGE types, but one of these could have been introduced earlier or may be better adapted for in vitro growth (Eriksson et al, 2010).…”

“…Three horse blood agar plates with overnight cultures of bacteria were harvested for each isolate, and preparation of genomic DNA for PFGE analysis was performed as described by Eriksson et al (2010). The purified DNA was digested with 40 u restriction enzyme Smal (New England BioLabs, Ipswich, MA, USA) according to the manufacturer's instructions.…”

“…Pulsed-field gel electrophoresis (PFGE) has been used previously to study the molecular epidemiology of poultry isolates of E. rhusiopathiae (Købke et al, 2005;Eriksson et al, 2009Eriksson et al, , 2010. Although the species is diverse by PFGE analysis, homogeneous banding patterns were observed during clinical outbreaks, which suggest that they may be of a clonal nature (Købke et al, 2005;Eriksson et al, 2010).…”

“…Erysipelas, caused by the Gram-positive bacterium Erysipelothrix rhusiopathiae, is an emerging cause of mortality in non-caged laying hens in Europe (Mazaheri et al, 2005;Eriksson et al, 2010;Stokholm et al, 2010). The bacterial colonies are small (0.5 mm) with a narrow alpha-haemolytic zone on blood agar plates and may be difficult to detect when more profusely growing bacteria are present in the sample.…”

“…Although the species is diverse by PFGE analysis, homogeneous banding patterns were observed during clinical outbreaks, which suggest that they may be of a clonal nature (Købke et al, 2005;Eriksson et al, 2010).…”