Cereus savings—successful use of dalbavancin in an immunocompromised patient with Bacillus cereus bacteremia

ABSTRACT Background Dalbavancin’s pharmacokinetics (long half-life, high tissue penetration, once-weekly dosing) make it an attractive alternative for patients with barriers to outpatient parenteral antimicrobial therapy or at risk for line-related complications. In this case, we used dalbavancin to promote timely discharge for an immunocompromised patient who experienced Bacillus cereus bacteremia due to a peripherally inserted central catheter (PICC) line-associated infection. Although B. cereus is known to cause line-related infections, we present a novel clinical case highlighting the successful use of dalbavancin in an immunocompromised patient with B. cereus bacteremia, and this approach also facilitated earlier discharge. Case Summary A 58-year-old woman with invasive ductal breast cancer on chemotherapy (docetaxel, carboplatin, trastuzumab, pertuzumab), mechanical aortic valve replacement, and other comorbidities presented with febrile neutropenia 2 weeks after her fifth chemotherapy cycle. A month prior, she had completed vancomycin for a suspected port infection. Admission laboratory values revealed pancytopenia (white blood cell count [WBC] 1.7 × 10⁹/L, absolute neutrophil count [ANC] 0.53 × 10⁹/L, hemoglobin 7.8 g/dL, and platelets 51 × 10⁹/L). Both sets of blood cultures obtained prior to empiric vancomycin grew B. cereus , with positive cultures throughout day 3 despite treatment. A transthoracic and transesophageal echocardiography excluded endocarditis. The PICC line was removed on day 2; blood cultures cleared by day 5, and neutropenia resolved on day 7. Given two prior catheter-related infections and logistical challenges with weekend discharge planning, the patient received a single 1,500 mg dose of intravenous dalbavancin rather than receiving a new line and continuing prolonged intravenous therapy. This facilitated discharge 4 days earlier than anticipated. At 2.5-week follow-up and visits at 30, 60, and 90 days, the patient remained clinically well without recurrence of infection. Conclusion This case highlights successful off-label use of dalbavancin in a complex case, suggesting that its use in such cases warrants further studies, especially when standard regimens can be logistically challenging.