#5521 TENCKHOFF CATHETER EXIT-SITE INFECTION BY ACTINOMYCES ODONTOLYTICUS: A RARE CASE
Authors: Freitas Mariana , Rodrigues Bárbara Beirão , Francisco Jose , Borges João , Oliveira Luís , Castro Rui , Morgado Teresa Pinto Ribeiro 
Published: June 2023

Abstract

Background and Aims
Actinomyces odontolyticus is an anaerobic Gram-positive bacteria, which can be found among the commensal flora of the mouth and oropharynx. Diagnosis of infections due to this microorganism can be difficult because of its rarity, indolent course and lack of specific symptoms. Only one case of exit-site infection (ESI) due to Actinomyces odontolyticus in a patient on continuous ambulatory peritoneal dialysis (CAPD) has been reported. This work aims to report a case of ESI due to this rare agent.

Method
We present a case of Tenckhoff catheter ESI due to Actinomyces odontolyticus in a patient on CAPD.

Results
Case report: We report the case of a 26-year-old woman with a personal history of dyslipidemia, arterial hypertension and end-stage chronic kidney disease caused by Alport Syndrome in a CAPD program since April 2016. In June 2020, the patient presented an episode of refractory ESI due to methicillin-sensitive Staphylococcus aureus and was submitted to a shaving of the external cuff of the Tenckhoff catheter, with good subsequent evolution. The patient had no complications related to the catheter until April 2021, when she presented purulent drainage through the exit-site associated with erythema of the surrounding area. The consecutive exit-site swabs were negative. She underwent antibiotic therapy with cotrimoxazole for 2 weeks with apparent resolution. However, in May 2021, the patient presents again erythema and purulent drainage and, at that time, a rare agent was isolated in the swab: Actinomyces odontolyticus with resistance to penicillin, amoxicillin, ceftriaxone and cotrimoxazole. Given this isolation, the patient was treated with doxycycline 100mg every 12 hours for 4 weeks. The evolution was favorable with resolution of the infection and absence of recurrence for a 6-month follow-up. At the end of this follow-up time, the patient was transplanted.

Conclusion
Actinomyces odontolyticus is a bacteria of the commensal flora of the oral cavity and upper gastrointestinal tract, which can acquire pathogenicity in situations of impaired mucosal integrity and in immunosuppressed patients. Infections caused by this agent are rare and represent a diagnostic challenge due to its growth in an anaerobic environment and prolonged isolation time (5 days to 4 weeks). The immunosuppression conferred by chronic kidney disease and the history of external cuff shaving may have propitiated the infection by this rare opportunistic agent in our patient. The ESI presented for the patient in the previous month, which did not have an identified agent, was possibly caused by Actinomyces odontolyticus, but it was not isolated probably due to culture difficulties. The treatment of Actinomyces infections is generally conservative with 2 to 4 weeks of high-dose of intravenous penicillin, followed by 2 to 6 months of oral antibiotic therapy. In case of allergy, regimens with ceftriaxone, doxycycline, clindamycin or carbapenems are recommended. There is no consensus on the duration of treatment, with some authors recommending a minimum of 2 to 6 weeks. The mentioned patient was treated with 4 weeks of doxycycline according to the sensitivity test and the result was favorable, without the need to remove the catheter.