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The Journal of the Japanese Society for Clinical Microbiology |
Biblioraphy Information
| ArticleTitle |
Identification and characterization of Brachyspira aalborgi and Brachyspira pilosicoli isolated from humans |
| Language |
J |
| AuthorList |
Yosuke Tanaka1), Yuko Matsumoto2), Naoki Shimada3), Momoko Anzai1), Tatsuya Ohno1), Nao Komatsu1), Masae Endo1) |
| Affiliation |
1) Department of Clinical Laboratory, St. Marianna University School of Medicine, Yokohama City Seibu Hospital
2) Yokohama City Institute of Public Haelth
3) Department of Diagnostic Pathology, St. Marianna University School of Medicine, Yokohama City Seibu Hospital |
| Publication |
J.J.C.M.: 26 (1), 30-40, 2015 |
| Received |
June 22, 2015 |
| Accepted |
September 20, 2015 |
| Abstract |
Human intestinal spirochetosis (HIS) is a disease caused by the gram-negative bacteria Brachyspira aalborgi and Brachyspira pilosicoli. B. aalborgi causes spirochetosis in only humans and other primates and is considered to be a harmless commensal. B. pilosicoli, on the other hand, is recognized as a pathogen in various animals, including pigs, dogs, and chickens; its clinical significance in HIS is controversial. Typically, HIS is diagnosed by the presence of a false brush border on colonic biopsy. B. pilosicoli is observed to be longer than B. aalborgi. The aim of this study was to improve the speed and frequency of detection of the Brachyspira species (spp.). We performed direct-smear Gram staining on colonic lavage fluid from 526 colonoscopy samples. Nineteen samples tested positive for Brachyspira. For the samples that tested positive, the age of patients ranged from 27 to 79 y (mean, 46.9 y), and they were predominantly male (17 of 19 patients). Following anaerobic culture on sheep blood agar, B. pilosicoli was isolated from five samples and B. aalborgi was isolated from four samples. The isolated bacteria were identified by 16S-rDNA sequencing. Most of the cases of HIS were associated with ulcerative colitis and diverticular disease. B. pilosicoli was associated with amebic colitis at a high frequency of 3 out of 5 cases. The Brachyspira spp. could not be isolated in approximately half of the patients (10 of 19); however, they all had a short false brush border on biopsy. Therefore, it was speculated that the isolation of B. aalborgi would be difficult. Of the direct-smear Gram staining positive patients, 17 underwent biopsy, and a false brush border was observed in 13 of the samples. We assumed that in order to increase the detection speed and frequency of Brachyspira spp. through direct-smear Gram staining, positive patients should be re-evaluated for other complications. Antimicrobial susceptibility testing and nitrocefin disk analysis revealed that B. pilosicoli strains were resistant to penicillin and possessed β-lactamase activity. The B. pilosicoli strains were found to possess OXA-136, a variant of the class D β-lactamase OXA-63. This finding was consistent with penicillin resistance in B. pilosicoli strains being attributed to class D β-lactamase OXA-136. |
| Keywords |
Brachyspira pilosicoli, Brachyspira aalborgi, Intestinal spirochetosis, OXA-136 |
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