A Very Rare Pathogen of Osteomyelitis: Alcaligenes faecalis.

Abstract

To the Editors: Alcaligenes faecalis is a Gram-negative, rod-shaped, oxidase-positive, catalase-positive, obligate aerobic, motile and nonfermenting bacteria.1 It is commonly found in the environment (soil or water) and in the human gut.2A. faecalis has been associated with various infections such as bacteremia, meningitis, endophthalmitis, endocarditis, skin and soft tissue infections, urinary tract infections, peritonitis, otitis media and pneumonia.3 Here, we present 2 patients with osteomyelitis due to A. faecalis, a rarely reported clinical condition in the literature. Patient 1: An 18-year-old female with a medical history of operated for meningomyelocele and pes cavus was admitted with worsening pain in her right lower extremity. On admission, she was afebrile with normal vital signs there was a chronic ulcerated wound with seropurulent discharge on the right foot. On the laboratory evaluation, there was no leukocytosis, C-reactive protein, and procalcitonin were negative, erythrocyte sedimentation rate was 35 mm/h. Clindamycin 30 mg/kg/d and cefotaxime 200 mg/kg/d intravenously (IV) were administered empirically. The contrast-enhanced magnetic resonance imaging showed cellulitis in soft tissue and osteomyelitis in the bone at the level of the 5th finger metatarsal base and proximal shaft (Fig. 1). Wound debridement was performed by orthopedics. She developed emesis and rash on day 4 and the antibiotic was changed to IV ciprofloxacin (30 mg/kg/d). Intraoperative wound culture grew A. faecalis which was sensitive to ampicillin, cefotaxime and gentamicin. Due to clinical improvement, treatment with ciprofloxacin continued and she was discharged after 15 days of IV therapy. The total treatment is planned to be completed in 8 weeks.FIGURE 1.: MRI (T2 weighted) showing osteomyelitis of the right foot. MRI indicates magnetic resonance imaging.Patient 2: A 15-year-old girl presented with a chronic ulcerated wound on her right foot. She had been operated twice for meningomyelocele and had pes planovalgus. She was afebrile and there was a chronic wound without any discharge on her right foot on admission. Laboratory evaluation revealed negative acute phase reactants and erythrocyte sedimentation rate was 24 mm/h. The empirical treatment was administered as IV cefotaxime and clindamycin. The contrast-enhanced magnetic resonance imaging showed findings suggestive of active osteomyelitis on the right calcaneus (Fig. 1). Orthopedics performed wound debridement and inserted vacuum-assisted closure therapy system. A. faecalis growth was detected in the tissue culture which was sensitive to ceftazidime and meropenem but resistant to amikacin. Her treatment was changed to IV ceftazidime (150 mg/kg/d). After vacuum-assisted closure treatment, it was planned to perform tissue repair by plastic surgery and to continue antibiotherapy IV due to the resistance pattern of the microorganism. Opportunistic infections and antimicrobial resistance associated with A. faecalis have been reported but osteomyelitis due to A. faecalis was documented in a few patients with diabetic foot ulcers in the literature.4 It is usually sensitive to beta-lactam antibiotics and trimethoprim/sulfamethoxazole and resistant to aminoglycosides and tetracyclines.5 Most of the previously documented cases have been successfully treated with amoxicillin/clavulanic acid but antibiotic resistance is an emerging problem. In summary, we present 2 patients with osteomyelitis due to A. faecalis, a rare cause of osteomyelitis. In addition to surgery, medical treatment should be arranged based on the antibiotic susceptibility results for successful and appropriate treatment.