In summer 2002 a five-year-old little blue penguin (Eudyptula minor) was presented to veterinary clinicians by husbandry staff agonal and died within 10 minutes despite emergency treatment. Microscopic examination of formalin-fixed, paraffin-embedded tissue sections revealed intravascular gram-positive, non-acid-fast bacilli in multiple organs, with necrosis of tips of intestinal villi and histiocytic infiltrates in pulmonary interstitium and hepatic sinusoids. Frozen samples of lung, liver, and intestine were cultured on blood agar under microaerophilic and anaerobic conditions at 37°C and 42°C. Cultures from lung, liver, and intestine yielded isolates identified by standard methods as Erysipelothrix rhusiopathiae. Genomic DNA was extracted from paraffin tissue blocks and cultures from lung, liver, and intestine, and a previously published protocol were modified slightly to allow amplification of E. rhusiopathiae DNA from formalin-fixed tissues.1 Single-band amplicons of comparable molecular weight to positive control products were obtained from bacterial cultures of lung, liver, and intestine, and from formalin-fixed paraffin-embedded sections of lung and intestine. Standard nucleotide-nucleotide BLAST sequence comparisons of PCR products against NCBI nucleotide databases demonstrated 99% nucleotide sequence identity with 16S SSU ribosomal DNA of E. rhusiopathiae and E. tonsillarum. To our knowledge, this is the first confirmed case of erysipelas in a penguin and expands our knowledge of the range of aquatic animals considered susceptible to acute Erysipelothrix sp. septicemia. Application of a previously published PCR protocol allowed retrospective analysis and correlation of culture results with formalin-fixed, paraffin-embedded tissues, which may be pertinent to cases from other aquatic species wherein this diagnosis is suspected.
1. Makino SI, Okada Y, Maruyama T, Ishikawa K, Tkahashi T, Nakamura M, et al. Direct and rapid detection of Erysipelothrix rhusiopathiae DNA in animals by PCR. J Clin Microbiol. 1994;32:1526–1531.