Tigecycline for the treatment of Acinetobacter infections:: A case series

BACKGROUND: Acinetobacter infections resistant to multiple classes of antibiotics have become prevalent in many institutions. Tigecycline has in vitro activity against Acinetobacter spp. and has been suggested as a therapeutic option in these infections. OBJECTIVE: To describe the clinical and microbiologic outcomes of patients who received tigecycline for the treatment of infections caused by Acinetobacter spp. at our institution. METHODS: A retrospective review was conducted of the medical records of 29 sequential patients who received tigecycline for treatment of Acinetobacter infections. The outcomes assessed for efficacy were clinical improvement or cure and microbiologic cure in evaluable patients. RESULTS: Patients received tigecycline a median of 30 days into hospitalization for a median of 11 days. Common indications were pneumonia (15 pts.), bacteremia (6), and urinary tract infection (3). Positive clinical outcomes (clinical cure or improvement) were seen in 8 (28%) of 29 patients. Of the 25 microbiologically evaluable patients, 11 (44%) had resolution of their cultures. Eleven patients had susceptibility testing performed, and the median minimum inhibitory concentration was 4 mu g/mL (range 3-8). CONCLUSIONS: In this case series, most patients did not have clinically or microbiologically favorable outcomes with tigecycline therapy. No patient had an isolate that was fully susceptible to tigecycline. Data from more studies are needed before tigecycline can be recommended for the treatment of Acinetobacter infections.