in three well-defined and highly divergent groups (31.0 % similarity). Nine (12 %) L. lactis strains were identified as bacteriocin producers. The bacteriocin produced by L. lactis subsp. cremoris WA2-67 was purified, and mass spectrometry and DNA sequencing revealed its identity to nisin Z (NisZ). Altogether, the results allowed the identification of 34 (45.3 %) putatively safe lactococci, including three bacteriocinogenic strains. This is the first description of tet(K), tet(O) and tet(T) in L. lactis. Moreover, ERIC-PCR fingerprinting has been shown for the first time as a valuable tool for genetic profiling of L. lactis strains from aquatic origin. A NisZ-producing L. lactis strain has been isolated for the first time from an aquatic environment, and this strain may be considered as a potential probiotic for rainbow trout farming for improving the quality and safety of fish and fish products.

Lactococcus garvieae is a Gram-positive, catalase negative coccus arranged in pairs or short chains, well-known as a fish pathogen. We report a case of Infective Endocarditis (IE) by L. garvieae in a native valve from a 68-year-old male with unknown history of contact with raw fish and an extensive history of heart disease. This case highlights the reliability of MALDI-TOF MS compared to conventional methods in the identification of rare microorganisms like this.