Ciprofloxacin for the Treatment of Infections Caused by Carbapenemase-Producing Gram-Negative Bacteria

<b>Background:</b> There is no experience with ciprofloxacin for the treatment of carbapenemase-producing Gram-negative bacteria (CP-GNB) infections. <b>Methods:</b> This is a retrospective single-centre study where we describe the clinical evolution of all consecutive adult patients who received ciprofloxacin monotherapy for the treatment of CP-GNB infections. Primary outcomes were clinical failure (defined as death, lack of clinical improvement or a switch to another drug) at day 14 and 30-day all-cause mortality. <b>Results:</b> Nineteen patients were included. Fifteen (79%) were men, the median age was 74 years (IQR 66-79) and the median Charlson comorbidity index was five (IQR 3-6.5). The most frequent infections were: nine complicated urinary tract infections, three soft tissue infections and three intra-abdominal infections. Twenty CP-GNBs were isolated (one patient had a coinfection): nine VIM-type-producing <i>Enterobacterales</i>, nine OXA-48-type-producing <i>Enterobacterales</i> and two VIM-type-producing <i>Pseudomonas aeruginosa</i>. Six (32%) patients had positive blood cultures, and one presented with septic shock. The median duration of ciprofloxacin treatment was 14 days (IQR 10-15). One patient presented with clinical failure at day 14. There was no 30-day mortality. Two patients exhibited microbiological recurrence at day 90. There were no reported adverse effects. <b>Conclusions:</b> Monotherapy with ciprofloxacin may be an alternative treatment for selected, clinically stable patients with ciprofloxacin-susceptible CP-GNB infections.