Klebsiella michiganensis sp. nov., a new bacterium isolated from a tooth brush holder

Abstract

Isolate W14(T) recovered from a household tooth brush holder was found to be gram-negative, a facultative anaerobic, non-motile, capsulated, and a non-endospore-forming straight rod. Based on phylogenetic analysis with 16S rRNA gene sequence, isolate W14(T) was affiliated to the genus Klebsiella. The closest phylogenetic relative was K. oxytoca with 99 % similarity in the 16S rRNA gene sequence. The major whole-cell fatty acids were C(16:0) (31.23 %), C(18:1ω6c)/C(18:1ω7c) (21.10 %), and C(16:1ω7c)/C(16:1ω6c) (19.05 %). The sequence similarities of isolate W14(T) based on rpoB, gyrA, and gyrB were 97, 98, and 98 % with K. oxytoca, and 97, 93, and 90 % with K. mobilis (=Enterobacter aerogenes), respectively. The ribotyping pattern showed a 0.46 similarity with K. oxytoca ATCC 13182(T) and 0.24 with K. mobilis ATCC 13048(T). The DNA G+C content of isolate W14(T) was 54.6 mol%. The DNA-DNA relatedness was 55.7 % with K. oxytoca ATCC 13182(T). Using the identification technology of MALDI-TOF mass spectrometry, the top matches for this isolate were K. oxytoca ATCC 13182(T) (Match Factor Score 1.998) and K. mobilis (Score 1.797). On the basis of phenotypic, biochemical, chemotaxonomic, and molecular studies, isolate W14(T) could be differentiated from other members of the genus Klebsiella including K. mobilis. Therefore, it is proposed that isolate W14(T) (=ATCC BAA-2403(T)=DSM 25444(T)) should be classified as the type strain of a novel species of the genus Klebsiella, K. michiganensis sp. nov.