Aims Campylobacter fetus subsp fetus (CFF) can cause intestinal illness, particularly in immunocompromised humans, with the potential to cause severe systemic infections. CFF is a zoonotic pathogen with a broad host range among farm animals and humans, inducing abortion in sheep and cows. The current paper describes a strain of CFF isolated from a patient with prosthetic valve endocarditis in Mercy University Hospital, Cork, Ireland, during 2017. Only five cases of C. fetus as a cause of prosthetic valve endocarditis have been reported in the literature, with no reports of biofilm formation within the species.
Methods The aetiological strain was speciated and subspeciated by the VITEK 2 NH card and matrix-assisted laser desorption ionisation time-of-flight mass spectrometry. CFF biofilm formation was analysed using a crystal violet staining method. C. jejuni National Collection of Type Cultures (NCTC) 11168 was used as a positive control organism. Strains were incubated statically in Mueller-Hinton broth and Mueller-Hinton broth supplemented with 0.025% sodium deoxycholate for 3 and 7 days at 37°C, microaerobically.
Results The CFF strain formed stronger attached biofilms on polystyrene plates on day 3 (72 hours) than the C. jejuni NCTC 11168 control strain, but were weaker than the control strain on day 7 in Mueller-Hinton broth. Monoculture of this C. fetus isolate was found to exist in three defined forms of biofilms (attached, air–liquid interface and floccules).
Conclusions This clinically significant C. fetus isolate showed considerable biofilm-forming capability, which we suggest conferred a survivalist advantage, contributing to the genesis of infective prosthetic valve endocarditis.
- campylobacter fetus
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Handling editor Tony Mazzulli.
Contributors All authors approved the final submission. CL is the primary author of the paper, and directly cosupervised and assisted with writing by BL and AC throughout the work. The clinical laboratory isolation and some follow-up work, along with some of the writing, were provided by JAO. CV is the cardiac surgeon who conducted the surgery and who provided the sample and the follow-up information/guidance. DO is the consultant microbiologist who presided over the clinical work and who advised on the details needed in the preparation of the manuscript and its revised edition. DB is part of the research group; he assisted in acquiring funding for the research work, and assisted with and approved the submission of the original and revised versions of the manuscript.
Funding The project was funded by the Department of Agriculture, Food and the Marine, Food Institutional Research Measure (15/F/641).
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.
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