Tenacibaculum maritimum CRISPR loci analysis and evaluation of isolate spoligotyping

AIMS

We performed in silico analysis of CRISPRcas loci from Tenacibaculum maritimum, evaluated spoligotyping as a subtyping method and genotyped uncharacterized Turkish isolates from European sea bass by multilocus sequence typing (MLST).

METHODS AND RESULTS

Spoligotyping was performed with primers designed to allow amplification and sequencing of whole CRISPR-arrays from 23 T. maritimum isolates. Twenty-three completed/draft genomes were also downloaded from the NCBI database and analysed. MLST of Turkish isolates was achieved with a well-established 7-gene scheme. Tenacibaculum maritimum genomes carry a structurally complete but partially defective class II CRISPRcas locus due to known amino acid substitutions in encoded Cas9 proteins. Our spacer identification suggests that the host range of bacteriophage P2559Y and Vibrio phage nt-1 include T. maritimum and that the most recurrent infection recorded by isolates has been with Tenacibaculum phage PTm5. Thirty-eight isolates with this CRISPRcas locus belonged to 25 spoligotypes and to 24 sequence types by MLST, respectively. According to MLST, T. maritimum isolates from Turkey are most related to previously defined sequence types ST3, ST40 and ST41 isolates from Spain, Malta and France.

CONCLUSIONS

The evaluated spoligotyping offers discriminatory power comparable to MLST.

SIGNIFICANCE AND IMPACT OF THE STUDY

Spoligotyping has potential as a quick, easy and cheap tool for subtyping of T. maritimum isolates.

Endogenous ochronosis

Endogenous ochronosis or alkaptonuria is a rare, autosomal recessive disease of tyrosine metabolism that is caused by a deficiency of the enzyme homogentisic acid oxidase. The disease results in the accumulation and deposition of homogentisic acid in the cartilage, eyelids, forehead, cheeks, axillae, genital region, buccal mucosa, larynx, tympanic membranes, and tendons. The disease generally presents in adults with arthritis and skin abnormalities; occasionally, involvement of other organs may be seen. A 49-year-old man was referred to our clinic with verrucous lesions on his hands. On physical examination, caviar-like ochronotic papules were found around his eyes and the helix cartilage of his ears, and on the dorsa of both hands. There were brown macules on the sclera (Osler's sign). The patient had arthritis and nephrolithiasis, and a sample of his urine darkened upon standing. Histopathological examination showed deposition of ochronotic pigment. High-dose ascorbic acid was given, and the patient showed improvement on follow-up examination 6 months later.