Lactococcus carnosus sp. nov. and Lactococcus paracarnosus sp. nov., two novel species isolated from modified- atmosphere packaged beef steaks

As part of a study investigating the spoilage microbiome of modifiedatmosphere packaged beef from Germany, four novel strains of lactic acid bacteria were isolated and subsequently taxonomically characterized by a polyphasic approach, which revealed that they could not be assigned to known species. The isolates were Gram stainingpositive, coccoid, facultatively anaerobic, nonmotile, catalasenegative and oxidasenegative. Morphological, physiological and phylogenetic analysis revealed a distinct lineage within the genus Lactococcus, with Lactococcus piscium and Lactococcus plantarum as closest relatives. Results indicated that they represented two different novel species with two strains, (TMW 2.1612(T)/TMW 2.1613 and TMW 2.1615(T)/TMW 2.1614), respectively. The two strains of both novel species shared identical 16S rRNA gene sequences but a MLSA allowed their intraspecies differentiation. The 16S rRNA gene sequences of TMW 2.1612(T) and TMW 2.1615(T) had a similarity of 99.85 % to each other and a similarity of 99.85 and 99.78 % the most closely related type strain of Lactococcus piscium, respectively. However, the ANIb value between the respective type strains TMW 2.1612(T) and TMW 2.1615(T), and the type strain of Lactococcus piscium was only 94.3 and 92.0 %, respectively, and 92.9 % between TMW 2.1612(T) and TMW 2.1615(T). The in silico DDH estimate value between the respective type strain TMW 2.1612(T) and TMW 2.1615(T) and the most closely related type strain of Lactococcus piscium was only 59.9 and 48.9 %, respectively, and 51.1 % between TMW 2.1612(T) and TMW 2.1615(T). Peptidoglycan type of strain TMW 2.1612(T) is Lys-Thr-Ala and major fatty acids are summed feature 8 and C-16:0. Peptidoglycan type of strain TMW 2.1615(T) is Lys-Ala and major fatty acids are C-16:0, C(19:0)cyclo omega 8c and summed feature 8. On the basis of polyphasic evidence, the meat isolates represent two novel species of the genus Lactococcus, for which the names Lactococcus carnosus sp. nov and Lactococcus paracarnosus sp. nov are proposed. The designated respective type strains are TMW 2.1612(T) (=DSM 111016(T) =CECT 30115(T)) and TWM 2.1615(T) (=DSM 111017(T) =CECT 30116(T)).