Mycobacterium liflandii strain KT1
The strain of M. liflandii that has been isolated from anuran sources at the University of California, Berkeley, has been designated KT1. KT1 is characterized and differentiated from its closest relatives, M. ulcerans and M. marinum, by the following molecular and physical traits.
The original isolation of M. liflandii is described in Trott et al., Comp. Med 2004. Further analysis of the pathogenesis and mycolactone toxin production of M. liflandii is reported in Mve-Obiang et al., Infection and Immunity 2005.
Restriction Fragment Length Polymorphism (RFLP) assay
KT1 has a three base-pair difference from M. ulcerans and M. marinum in its Internal Transcribed Spacer (ITS) that results in a lack of a Fok1 restriction enzyme site that is present in M. ulcerans and M. marinum. Amplification of ITS (as described in Trott et al., Comp. Med 2004) followed by Fok1 digestion results in a RFLP with a major product of 213 base-pairs for both M. ulcerans and M. marinum, and a product band of 266 base-pairs for M. liflandii.
The following additional comparative differences were also used to identify M. liflandii KT1. The specific sequences can be found in Trott et al., Comp. Med 2004
1) KT1 is identical to M. ulcerans in the 5' signature region of RNA Polymerase subunit B (rpoB) and one base-pair off from M. ulcerans in the 3' region. It is three base-pairs different from M. marinum in the 5' region of rpoB and identical to M. marinum in the 3' region of rpoB.
2) KT1 is positive for both M. ulcerans-specific Insertion Sequences, IS2404 and IS2606.
3) KT1 is identical to the M. marinum heat shock protein 65 (hsp65) and 3 base-pairs different from M. ulcerans.
4) KT1 is 2 base-pairs different from the 16s ribosomal RNA gene (16sRNA) of M. marinum and 3 base-pairs different from M. ulcerans.
KT1 is a non-photochromogenic acid-fast mycobacterium. On Middlebrook 7H11 media supplemented with OADC, colonies are non-pigmented and slightly buff-colored, with rough morphology. KT1 has an optimal growth temperature of 28ºC with no growth seen at 35ºC. Growth rate on Lowenstein-Jenson is 30-35 days.