Dataset Information

Cefiderocol treatment for carbapenem-resistant Acinetobacter baumannii infection in the ICU during the COVID-19 pandemic: a multicentre cohort study.

ABSTRACT:

Objectives

To analyse the impact of cefiderocol use on outcome in patients admitted to the ICU for severe COVID-19 and further diagnosed with carbapenem-resistant Acinetobacter baumannii (CR-Ab) infection.

Methods

Retrospective multicentre observational study was performed at four Italian hospitals, from January 2020 to April 2021. Adult patients admitted to ICU for severe COVID-19 and further diagnosed with CR-Ab infections were enrolled. Patients treated with cefiderocol, as compassionate use, for at least 72 h were compared with those receiving alternative regimens. Primary endpoint was all-cause 28 day mortality. The impact of cefiderocol on mortality was evaluated by multivariable Cox regression model.

Results

In total, 107 patients were enrolled (76% male, median age 65 years). The median time from ICU admission to CR-Ab infection diagnosis was 14 (IQR 8-20) days, and the main types of CR-Ab infections were bloodstream infection (58%) and lower respiratory tract infection (41%). Cefiderocol was administered to 42 patients within a median of 2 (IQR 1-4) days after CR-Ab infection diagnosis and as monotherapy in all cases. The remaining patients received colistin, mostly (82%) administered as combination therapy. All-cause 28 day mortality rate was 57%, without differences between groups (cefiderocol 55% versus colistin 58% P = 0.70). In multivariable analysis, the independent risk factor for mortality was SOFA score (HR 1.24, 95% CI 1.15-1.38, P < 0.001). Cefiderocol was associated with a non-significant lower mortality risk (HR 0.64, 95% CI 0.38-1.08, P = 0.10).

Conclusions

Our study confirms the potential role of cefiderocol in the treatment of CR-Ab infection, but larger clinical studies are needed.

SUBMITTER: Pascale R

PROVIDER: S-EPMC8599913 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Objectives: Carbapenem-resistant Acinetobacter baumannii (CRAB) are one of the most difficult pathogen to treat. The only drug recently approved by the FDA that is active against CRAB is cefiderocol. However, recent studies have shown higher all-cause mortality rate in the group of patients treated with cefiderocol, that may be due to heteroresistance, a phenotype characterized by the survival of a small proportion of cells in a population seemingly isogenic. Previous studies showed that adding human fluids to CRAB cultures can lead to CFDC heteroresistance. To better understand the nature of this phenomenon, we carried out molecular and phenotypic analyses of CRAB heteroresistant bacterial subpopulations. Methods: The CRAB strain AMA40 was cultured in the presence of cefiderocol and human pleural fluid (HPF) to isolate heteroresistant variants. Two of them, AMA40 IHC_1 and IHC_2, were subjected to whole genome sequencing and transcriptomic analysis to identify the mutations and transcriptomic changes responsible for the development of cefiderocol resistance. The impact of mutations on the pharmacodynamic activity of cefiderocol was assessed by susceptibility testing, EDTA and Boronic acid inhibition analysis, biofilm formation, and static time-kill assays. Results: Variants AMA40 IHC_1 and IHC_2 had 53 mutations, forty of which were common to both heteroresistant strains. None of the mutations are located inside genes associated with iron-uptake systems or β-lactam resistance. However, pipA, a gene associated with iron homeostasis in other species, was mutated in heteroresistant strains. Transcriptomic analyses revealed modifications in levels of expression of genes associated with antibiotic resistance. The blaNDM-1, blaADC-2, pbp3, and pbp1 were expressed at higher levels. At the same time, the carO and ompA genes’ expression was reduced. Collateral resistance to amikacin was observed in the heteroresistant variants. Static time-kill assays showed that when CA-MHB was supplemented with human serum albumin, the main protein component of HPF, cefiderocol killing activity was considerably reduced in all three strains. Conclusions: We conclude that heteroresistance to cefiderocol in CRAB, when exposed to fluids containing high HSA, is caused by mutations and modifications in the expression of genes associated with resistance to β-lactams.

Project description:BackgroundWith an increase in the use of colistin methansulfonate (CMS) to treat carbapenem-resistant Acinetobacter baumannii infections, colistin resistance is emerging.MethodsPatients with infection or colonization due to colistin-resistant A. baumannii were identified at a hospital system in Pennsylvania. Clinical data were collected from electronic medical records. Susceptibility testing, pulsed-field gel electrophoresis (PFGE), and multilocus sequence typing (MLST) were performed. To investigate the mechanism of colistin resistance, lipid A was subjected to matrix-assisted laser desorption/ionization mass spectrometry.ResultsTwenty patients with colistin-resistant A. baumannii were identified. Ventilator-associated pneumonia was the most common type of infection. Nineteen patients had received intravenous and/or inhaled CMS for treatment of carbapenem-resistant, colistin-susceptible A. baumannii infection prior to identification of colistin-resistant isolates. The 30-day all-cause mortality rate was 30%. The treatment regimen for colistin-resistant A. baumannii infection associated with the lowest mortality rate was a combination of CMS, a carbapenem, and ampicillin-sulbactam. The colistin-susceptible and -resistant isolates from the same patients were highly related by PFGE, but isolates from different patients were not, suggesting evolution of resistance during CMS therapy. By MLST, all isolates belonged to the international clone II, the lineage that is epidemic worldwide. Phosphoethanolamine modification of lipid A was present in all colistin-resistant A. baumannii isolates.ConclusionsColistin-resistant A. baumannii occurred almost exclusively among patients who had received CMS for treatment of carbapenem-resistant, colistin-susceptible A. baumannii infection. Lipid A modification by the addition of phosphoethanolamine accounted for colistin resistance. Susceptibility testing for colistin should be considered for A. baumannii identified from CMS-experienced patients.