Ceftazidime/avibactam and ceftolozane/tazobactam for the treatment of extensively drug-resistant Pseudomonas aeruginosa post-neurosurgical infections: three cases and a review of the literature

Purpose: Post-neurosurgical infection caused by extensively drug resistant Pseudomonas aeruginosa (XDR-PA) are becoming a matter of great concern due to limited therapeutic options. Although not approved for these indications, the new BetaLactam-BetaLactamase Inhibitor combinations (BLBLIs) could represent a valid salvage treatment. We describe one nosocomial meningitis and two cervical osteomyelitis due to an XDR-PA who were treated with ceftazidime/avibactam (CZA) and ceftolozane/tazobactam (C/T) and review the literature. Methods: The first and the third patients developed an osteomyelitis following cervical stabilization surgery due to an XDR-PA. Although the first patient started treatment with a high dose of C/T, resistance to C/T occurred, so therapy was switched to CZA plus aztreonam. The third patient switched to aztreonam plus CZA due to development of acute kidney injury during therapy with colistin. The second patient had an XDR-PA meningitis following the insertion of an external ventricular catheter and he was treated with C/T plus meropenem and amikacin. Results: All three cases reported were successfully conservatively treated thanks to the use of the new BLBLIs with different combinations. Only few experiences demonstrated an equally favorable outcome: one patient treated with C/T plus fosfomycin for otogenic meningitis caused by an XDR-PA and another case of XDR-PA post-surgical meningitis with CZA in combination with colistin. Finally, the combination of CZA plus aztreonam has proven to be effective on XDR-PA only in limited mostly in vitro studies. Conclusion: These recently developed antibiotics, C/T and CZA are promising and complementary therapy options against post-neurosurgical hard-to-treat P. aeruginosa infections. Further prospective real-life studies are required to validate these findings in this special setting.