In-vitro Activity of Ceftolozane-Tazobactam Against Multi-Drug ResistantPseudomonas aeruginosa in a Tertiary Care Center in Al-Ahsa, KSA

Abstract

Abstract Introduction/Objective Pseudomonas aeruginosa is a major nosocomial pathogen often causing serious multi-drug resistant (MDR) infections. Resistant strains, including carbapenem-resistant (CR), are increrasing especially in intensive care units (ICU) which limits treatment options to nephrotoxic aminoglycosides and polymyxins, and results in failure of initial therapy, significant mortality, morbidity and cost. Ceftolozane-tazobactam (CT) is a novel antimicrobial showing good activity against MDR and CR isolates; however, reports of resistance are increasing. Data from KSA is scarce. The aim of this study is to determine the in-vitro activity of CT against MDR and CR P. aeruginosa Methods/Case Report Single-center retrospective observational study of patients with P. aeruginosa infection in 2020 and 2021. Data including susceptibility to anti-pseudomonal drugs were retreived from medical records. Non-duplicate consecutive first isolates from all clinical specimens were included. MDR strains were labeled following international guidelines. Data was analyzed using the Statistical Package for the Social Sciences software (SPSS®). Results (if a Case Study enter NA) Out of 538 isolates collected, 98 (18.2%) were CR and 62 (11.5%) were MDR. MDR isolates were mainly retrieved from respiratory samples (44%), bedsores (29%) and urine (21%). 62% of CR and 76% of MDR isolates were from patients >60 years of age; significantly higher than younger patients. 85% (83/98) of CR and 81% (50/62) of MDR isolates came from ICU patients where the prevalence of CR and MDR was 34% and 20%, respectively; significantly higher than other areas. Overall sensitivity to CT was 97%, 85% for CR and 71% for MDR isolates. Only amikacin performed better with 98% sensitivity overall, 92% for CR and 86% for MDR. Sensitivity to CT in ICU was 94%. CT was effective against 83% of CR and 70% of MDR isolates second only to amikacin (90% and 84%, respectively). Other tested antimicrobials were ineffective against MDR and CR isolates. Conclusion CT shows good in-vitro activity against MDR and CR P. aeruginosa isolates. It may provide a therapeutic option to treat urinary tract infections and hospital-acquired or ventilator-associated pneumoniae especially in critically ill elderly patients. More studies on treatment responses and emergence of resistance are required to establish the role of CT as an effective treatment of serious P. aeruginosa infections.