ISSN: 1859 - 2872
Preliminary effectiveness of aztreonam plus ceftazidime/avibactam for the treatment of pan-drug-resistant Enterobacterales infections: A retrospective comparative with colistin-based therapy at 108 Military Central Hospital
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Abstract
Objective: To evaluate the clinical and microbiological effectiveness, as well as nephrotoxicity, of aztreonam plus ceftazidime/avibactam (AZT+CAZ-AVI) compared with colistin-based regimens in patients with pan-drug-resistant Enterobacterales (PDR-E) infections treated at 108 Military Central Hospital between October 2025 and May 2026. Subject and method: We retrospectively reviewed all patients with PDR-E infections who received either AZT+CAZ-AVI or a colistin-based regimen for at least 72 hours. Microbiological response at the end of targeted antimicrobial therapy (EoT) was defined as at least one negative culture obtained from the primary site of infection after treatment initiation. Clinical failure was defined as death, terminal discharge, or the need to switch to an alternative antimicrobial regimen because of persistent or progressive infection. Result: A total of 35 patients with PDR-E infections were included, of whom 16 received AZT+CAZ-AVI and 19 received a colistin-based regimen. In the AZT+CAZ-AVI group, pathogens included Klebsiella pneumoniae (13/16, 81.2%) and Escherichia coli (3/16, 18.8%). All isolates tested (14/14, 100%) carried the bla-NDM. The primary sites of infection were the lungs (8/16, 50.0%), bloodstream (4/16, 25.0%), urinary tract (3/16, 18.8%), and intra-abdominal (1/16, 6.2%). The AZT+CAZ-AVI and colistin groups were comparable with respect to causative pathogens, infection sites, and comorbidity burden (Charlson Comorbidity Index: 2.0 (2.0 - 3.7) vs. 3.0 (2.0 - 5.0), p=0.23). Although patients receiving AZT+CAZ-AVI had significantly higher disease severity (SOFA score: 4.0 (2.2 - 12.5) vs. 0.0 (0.0 - 2.0), p=0.001), they showed a trend toward a lower rate of clinical failure (20.0% vs. 42.1%, p=0.27). Among patients with available follow-up cultures, microbiological response was also numerically higher in the AZT+CAZ-AVI group (11/12 [91.7%] vs. 7/9 [77.8%], p=0.55). Acute kidney injury occurred significantly more frequently in the colistin group than in the AZT+CAZ-AVI group (36.8% vs. 14.3%, p=0.04). Conclusions: Aztreonam plus ceftazidime/avibactam demonstrated favorable clinical and microbiological outcomes for the treatment of infections caused by pan-drug-resistant Enterobacterales and was associated with a significantly lower incidence of acute kidney injury than colistin-based regimens.
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References
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