Summary

A 57-year-old man presented with native mitral valve endocarditis caused by Lactococcus garvieae, a known animal pathogen that is increasingly being reported as a cause of human infections. The organism was cultured in four sets of blood cultures and identification was initially made by matrix-assisted laser desorption/ionisation—time of flight mass spectrometry and confirmed by 16S rDNA PCR of the blood culture isolate. He was successfully treated with 6 weeks of both amoxicillin and gentamicin and underwent valve replacement surgery after 4 weeks of antimicrobial treatment. The removed valve was sterile but L. garvieae DNA was detected on the valve using 16S rDNA PCR. The cause of the L. garvieae infection could not be ascertained but flexible sigmoidoscopy demonstrated colonic polyps, which have been linked to infection with this organism.