Background: Infections with for Corynebacterium kroppenstedtii are rare. We present a challenging case with C. kroppenstedtii infection.
Methods: The clinical chart of the patient was reviewed. The bacteria was identified using blood chocolate and chromagar plates and further by MALDI-TOF-VITEK MS. The organism was then placed into sheep blood agar supplemented by 1% Tween 80 and further identified by 16SRNA and compared to BLAST database.
Results: A 35-year-old pregnant woman (week 20) with a 2-year history of recurrent bilateral breast abscesses was admitted due to pain, swelling and erythema of the right breast, without fever. 7 weeks earlier a small abscess was drained at the same site. WBC 17.6; CRP 7.3. Ultrasound demonstrated a 5*1.8 cm collection of fluid consistent with an abscess and a smaller cystic finding suspected as an additional abscess. Surgical drainage yielded a large amount of purulent fluid. No bacteria were seen on direct Gram smear. Intravenous daptomycin, 500 mg/d was administered based on culture of the prior aspiration that was positive for Corynebacterium spp. After 48 hours the bacteria grew poorly on blood agar, but after supplementation with Tween 1% rich growth was seen after 24 hours. MALDI-TOF MS identified C. kroppenstedtii. 16s RNA analysis validated the identification. Clinical improvement was short lived and the patient underwent 5 additional surgical and subcutaneous aspirations as well as long-term antibiotic courses (daptomycin, piperacillin-tazobactam, ceftazidime and clindamycin). Recurrent aspirate cultures were positive for C. kroppenstedtii. Surgical pathology demonstrated non-specific inflammatory changes consistent with multi-abscesses without granuloma. 2 months later the patient is still receiving clindamycin and still requires further draining procedures (the last one performed 3 days ago).
Conclusions: Corynebacterium are normal skin flora, thus it can be difficult to distinguish between infection, colonization and contamination. Clinical isolates of C. kroppenstedtii, first described in 2002, are isolated almost exclusively from female patients with breast abscesses or granulomatous mastitis. In most cases a longstanding process occurred, similar to our case, frequently requiring treatment for months and years with many recurrences resulting in breast mutilation. Some reports suggest that lipophilic antibiotics such as ciprofloxacin and doxycycline could be more effective. As our patient is pregnant, we preferred avoiding potential teratogenic treatments.