Bloodstream infection with pandrug-resistant Alcaligenes faecalis treated with double-dose of tigecycline

INTRODUCTION: Alcaligenes faecalis is a species of gram-negative, rod-shaped, aerobic bacteria commonly found in the environment. A. faecalis-associated nosocomial infections are common in hospitalized patients, but serious life threatening infections are rare. Here, we report a rare case of BSI with A. faecalis resistant to all available antibiotics; successfully treated with double-dose of tigecycline. PRESENTATION OF CASE: A 60-year-old female presented with A. faecalis bloodstream infection, where the organism was completely resistant to all commercially available antibiotics including polymyxins and tigecycline. The physical condition of the patient was deteriorating and there were no active antibiotics available to prescribe based on sensitivities. Despite the organism’s resistance to tigecycline, double-dose of tigecycline therapy (100 mg twice daily, intravenously after a 200 mg single intravenous loading dose) was prescribed intentionally for the treatment of this infection. The organism was completely eradicated from the bloodstream of that patient within the 5 days of therapy-initiation. DISCUSSION: Double-dose of tigecycline maintains a higher serum drug concentration rather than the standard dose, and in this case, double-dose of tigecycline completely cleared the pandrug-resistant A. faecalis from the blood where initially, that organism was resistant to tigecycline. Previously, A. faecalis isolates were found resistant to fluoroquinolones, but here it was found very rarely resistant to even reserve antibiotics, polymyxins, carbapenems and tigecycline. CONCLUSION: Pandrug-resistant A. faecalis-associated bloodstream infection is a very uncommon case and double-dose of tigecycline may be an effective option to treat it.