Genetic diversity of Leptotrichia and description of Leptotrichia goodfellowii sp nov., Leptotrichia hofstadii sp nov., Leptotrichia shahii sp nov and Leptotrichia wadei sp nov.

Sixty strains of Gram-negative, anaerobic, rod-shaped bacteria from human sources initially assigned to Leptotrichia buccalis (n = 58) and 'Leptotrichia pseudobuccalis' (n = 2) have been subjected to polyphasic taxonomy. Full-length 16S rDNA sequencing, DNA-DNA hybridization, RAPID, SDS-PAGE of whole-cell proteins, cellular fatty acid analysis and enzymic/biochemical tests supported the establishment of four novel Leptotrichia species from this collection, Leptotrichia goodfellowii sp. nov. (type strain LB 57(T) = CCUG 32286(T) = CIP 107915(T)), Leptotrichia hofstadii sp. nov. (type strain LB 23(T) = CCUG 47504(T) = CIP 107917(T)), Leptotrichia shahii sp. nov. (type strain LB 37(T) = CCUG 47503(T) = CIP = 107916(T)) and Leptotrichia wadei sp. nov. (type strain LB 16T = CCUG 47505(T) = CIP 107918(T)). Light and electron microscopy showed that the four novel species were Gram-negative, non-spore-forming and non-motile rods. L. goodfellowii produced arginine dihydrolase, beta-galactosidase, N-acetyl-beta-glucosaminidase, arginine arylamidase, leucine arylamidase and histidine arylamidase. L. shahii produced alpha-arabinosidase. L. buccalis and L. goodfellowii fermented mannose and were beta-galactosidase-6-phosphate positive. L. goodfellowii, L. hofstadii and L. wadei were beta-haemolytic. L. buccalis fermented raffinose. With L. buccalis, L. goodfellowii showed 3.8-5.5% DNA-DNA relatedness, L. shahii showed 24.5-34.1% relatedness, L. hofstadii showed 27.3-36.3% relatedness and L. wadei showed 24.1-35.9% relatedness. 16S rDNA sequencing demonstrated that L. hofstadii, L. shahii, L. wadei and L. goodfellowii each formed individual clusters with 97, 96, 94 and 92% similarity, respectively, to L. buccalis.