Ceftolozane-tazobactam for the treatment of osteomyelitis caused by multidrug-resistant pathogens: a case series.

Ceftolozane-tazobactam (CT) is a recently approved novel cephalosporin and β-lactamase inhibitor combination agent with activity against various Gram-positive and Gram-negative pathogens, including several multidrug-resistant (MDR) Gram-negative organisms. CT is currently approved by the US Food and Drug Administration for the treatment of complicated intrabdominal infection and complicated urinary tract infection at a dose of 1.5 g intravenously every 8 h. This agent is an attractive option for MDR osteomyelitis (OM) treatment, but clinical data is limited to case reports and series. Here we report a series of five patients with MDR OM who were treated with CT. Pathogens involved in these infections were MDR (two isolates) and MDR (four isolates). Two patients were disease free 6 months after therapy was discontinued, one required an additional curative surgical procedure, and two (both on high-dose therapy) developed adverse reactions likely related to CT that necessitated early antibiotic discontinuation.