First clinical description of Eggerthia catenaformis bacteremia in a patient with dental abscess
A 54-year-old previously healthy male was admitted to the department of oto-rhino-laryngology (ORL) with a one week his- tory of progressive sore throat, swallowing dif fi culties, toothache, referred otalgia and skin redness on the neck. One month prior to admission he had seen a local dentist for a molar fi lling. Three days before admission he had sought treatment at the same dentist for pain in a molar tooth, but despite treatment with oral phenox- ymethylpenicillin his condition deteriorated. Temperature on admission was 39.1 C, respiratory rate 32 breaths/min, heart rate 73 beats/min, blood pressure 143/68 mmHg and saturation 99% on ambient air. The main physical fi ndings were general malaise, fever, marked trismus and a non-progressing erythematous rash on his anterior neck extending from the jaw to the supraclavicular level. Due to trismus, thorough examination of the teeth and tonsils was impossible.
Acute cervicothoracic computed tomography (CT) scan with intravenous contrast demonstrated a complex of fl uid accumula- tions with air bubbles in the neck including the tonsil area, infra- temporal space, the base of the tongue, submental triangle and submandibular gland on the right side ( Fig. 1 .). There was no affection of the neck below the hyoid bone or affection of the thorax. The initial diagnosis was sepsis and cervical necrotizing fasciitis with a peritonsillar or dental abscess as the primary focus. Two sets of blood cultures were obtained, and antibiotic treat- ment with intravenous piperacillin/tazobactam and clindamycin was initiated. Acute tonsillectomy was performed within 4.5 h after admis- sion. There was no evidence of peritonsillar abscess and incision of the inner mandible mucosa revealed vital, bleeding tissue which rebutted the suspicion of necrotizing fasciitis. The abscess cavity of the right second mandibular molar was drained by incision and tooth extraction. Culture samples from the cavity grew a mixed culture of Eggerthia catenaformis and anginosus group streptococci. After 48 and 67.5 h of incubation respectively both anaerobic blood culture bottles (BacT/Alert; bioM erieux, Marcy l ’ Etoile, France) were positive for Eggerthia catenaformis . Daily reopening of the abscess cavity in local anaesthesia was performed. Additional second minor surgical drainage was needed 7 days from admission. The initial antibiotic regimen continued for 5 days and was changed according to culture and susceptibility results to intrave- nous benzylpenicillin and metronidazole for another 6 days.
The isolates were identi fi ed by matrix assisted laser desorption ionization time-of- fl ight mass spectrometry (MALDI-TOF MS) using a Bruker MALDI Biotyper with Bruker Biotyper 3.4 software and library version V184.108.40.206 (Bruker Daltonik, Bremen, Germany) ac- cording to manufacturer's instructions. Unambiguous diagnosis of Eggerthia catenaformis were achieved on the isolates from the blood cultures and from the abscess cavity with scores of 2.064 and 2.072 respectively. This is in accordance with a previously published study using MALDI-TOF MS for identi fi cation of a blood culture isolate of Eggerthia catenaformis . Identi fi cation of the blood isolate was veri fi ed by partial 16S rDNA gene sequencing (FAST MicroSeq ® 500 16S rDNA PCR Kit and MicroSeq ® 500 16S rDNA Sequencing Kit, Applied Biosystems, Life Technologies, Warrington, UK). The obtained sequence (464 bp) was compared with the EzTaxon database . 100% sequence similarity was obtained for Eggerthia catenaformis (GenBank accession no. AGEJ010 00001) followed by Sharpea azabuensis (89% sequence similarity, GenBank accession no. AB210824) and Kandleria vitulina (88% sequence similarity, GenBank accession no. AB210825). Antimicrobial sus- ceptibility was determined by the Etest (bioM erieux, Craponne, France) and M.I.C. Evaluator (Oxoid ltd. Basingstoke, Harts, UK) gradient methods on brucella blood agar supplemented with he- min and vitamin K (Becton Dickinson GmbH, BD Diagnostics, Hei- delberg, Germany) according to the manufacturer's instructions (Table 1 ). Clindamycin results were con fi rmed after 48 h of incu- bation. Bacteroides fragilis ATCC 25285 was used as a quality control. In summary, this case report demonstrates the value of MALDI- TOF MS for identi fi cation of Eggerthia catenaformis . We found it susceptible to common antibiotics used for anaerobic infections. The patient responded to a combination of surgical intervention and treatment with intravenous antibiotics. Routine procedures for managing severe odontogenic infections appear to be appropriate for the treatment of Eggerthia catenaformis dental abscess with associated bacteremia.