Meropenem plus Ertapenem and Ceftazidime-Avibactam plus Aztreonam for the Treatment of Ventilator Associated Pneumonia Caused by Pan-Drug Resistant Klebsiella pneumonia

Introduction: Gram-negative bacteria (GNB) account for about 70% of infections in the intensive care unit (ICU) setting and are associated with significant morbidity and mortality. In recent years, pan-drug resistant (PDR) strains, strains that are not susceptible to any antibiotic, have been emerged and new treatment strategies are required. Results: Fifty eligible patients were recruited in the three groups. A statistically significant reduction in the Sequential Organ Failure Assessment (SOFA) score was observed in the control group on day 4 in comparison to day 0 of VAP (p = 0.005). The Clinical Pulmonary Infection Score (CPIS) was also reduced on day 4 (p = 0.0016) and day 7 in comparison to day 0 (p = 0.001). Patients that received combination therapy, CAZ-AVI + ATM and DCT, presented with a lower SOFA score and CPIS on day 7 in comparison to day 0 (p = 0.0288 and p = 0.037, respectively). No differences in the Delta SOFA score and Delta CPIS were found between the groups. The control group presented with a significantly lower ICU stay and duration of mechanical ventilation (p = 0.03 and p = 0.02, respectively). There was no difference in mortality. Materials and methods: This is a retrospective analysis. This study was conducted in a mixed ICU in the University Hospital of Larissa, Thessaly, Greece during a three-year period (2020-2022). Patients suffering from ventilator associated pneumonia (VAP) due to carbapenem-resistant K. pneumonia (CR-KP) were divided in three different groups: the first one was treated using ceftazidime-avibactam plus aztreonam (CAZ-AVI + ATM group), the second was treated using double carbapenems (DCT group), and the last one (control group) received appropriate therapy since the strain was susceptible in vitro to at least to one antibiotic. Conclusions: Treatment with CAZ-AVI +ATM or DCT may offer a clinical benefit in patients suffering with infections due to PDR K. pneumoniae. Larger studies are required to confirm our findings.