Corynebacterium lizhenjunii sp. nov., isolated from the respiratory tract of Marmota himalayana, and Corynebacterium qintianiae sp. nov., isolated from the lung tissue of Pseudois nayaur

Abstract

Four Gram-stain-positive, non-motile and asporous bacilli (strains ZJ-599T, ZJ-621, MC1420T and MC1482), isolated from animal tissue and environmental samples collected on the Qinghai-Tibet Plateau, PR China, were taxonomically characterized. Based on the results of 16S rRNA gene sequence analyses, the closest relatives of strains ZJ-599T and ZJ-621 were Corynebacterium endometrii LMM-1653T (97.5 %), Corynebacterium phocae M408/89/1T (96.5 %) and Corynebacterium flavescens OJ8T (96.3 %), whereas strains MC1420T and MC1482 were closest to Corynebacterium sanguinis CCUG 58655T (98.9 %), Corynebacterium mycetoides DSM 20632T (98.4 %) and Corynebacterium lipophiloflavum DSM 44291T (97.9 %). The results of rpoB gene sequence similarity analysis indicated that C. phocae M408/89/1T and C. sanguinis CCUG 58655T were closest to strains ZJ-599T/ZJ-621 (83.5 %) and MC1420T/MC1482 (91.8 %), respectively. The two novel type strains shared a similarity of 95.2 % in 16S rRNA and 81.3 % in rpoB gene sequences. The TAP-PCR DNA fingerprint and MALDI-TOF MS spectrum patterns clearly differentiated the novel isolates within and between each pair of strains. Strain ZJ-599T had 21.9–22.4 % digital DNA–DNA hybridization (dDDH) scores with C. endometrii LMM-1653T, C. phocae M408/89/1T and C. flavescens OJ8T, and 72.3–72.9 % of average nucleotide identity (ANI) with them. Similarly, strain MC1420T had 22.9–23.7 % dDDH values with C. sanguinis CCUG 58655T, C. mycetoides DSM 20632T and C. lipophiloflavum DSM 44291T, and 80.4–81.3 % ANI scores with them. Strain ZJ-599T had a 23.1 % dDDH value and 70.5 % ANI score with strain MC1420T, both below the corresponding thresholds for species delineation. Strains ZJ-599T and MC1420T both contain mycolic acids and have MK-8(H2) and MK-9(H2) as the predominant respiratory quinones, meso-diaminopimelic acid as the diagnostic diamino acid, and C18 : 1  ω9c as the main fatty acid. C17 : 1  ω8c and C15 : 1  ω8c were predominant in strain ZJ-599T in contrast to C17 : 1  ω7c being predominant in strain MC1420T. The main polar lipids in strain ZJ-599T were diphosphatidylglycerol, phosphatidylinositol and one unidentified glycolipid, while strain MC1420T had diphosphatidylglycerol, phosphatidylglycerol and one unidentified lipid as the major components. Since the two pairs of novel strains (ZJ-599T/ZJ-621, MC1420T/MC1482) distinctly differ from each other and from their nearest relatives, two novel species of the genus Corynebacterium are proposed, namely Corynebacterium lizhenjunii (type strain ZJ-599T=GDMCC 1.1779T=JCM 34341T) and Corynebacterium qintianiae (type strain MC1420T=GDMCC 1.1783T=JCM 34340T), respectively.