In Vitro Antimicrobial Activity of the Siderophore Cephalosporin Cefiderocol against <i>Acinetobacter baumannii</i> Strains Recovered from Clinical Samples
Background: Cefiderocol is a siderophore cephalosporin that exhibits antimicrobial activity against most multi-drug resistant Gram-negative bacteria, including Enterobacterales, <i>Pseudomonas aeruginosa</i>, <i>Acinetobacter baumannii</i>, and <i>Stenotrophomonas malto...
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| Main Authors: | , , , , , , , , , , |
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| Format: | article |
| Language: | EN |
| Published: |
MDPI AG
2021
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| Subjects: | |
| Online Access: | https://doaj.org/article/da982e6f724b42c58e58628aa31e36b7 |
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| Summary: | Background: Cefiderocol is a siderophore cephalosporin that exhibits antimicrobial activity against most multi-drug resistant Gram-negative bacteria, including Enterobacterales, <i>Pseudomonas aeruginosa</i>, <i>Acinetobacter baumannii</i>, and <i>Stenotrophomonas maltophilia</i>. Methods: A total of 20 multidrug-resistant <i>A. baumannii</i> strains were isolated from 2020 to 2021, molecularly characterized and tested to assess the in vitro antibacterial activity of cefiderocol. Thirteen strains were carbapenem-hydrolysing oxacillinase OXA-23-like producers, while seven were non-OXA-23-like producers. Minimum inhibitory concentrations (MICs) were determined by broth microdilution, considered as the gold standard method. Disk diffusion test was also carried out using iron-depleted CAMHB plates for cefiderocol. Results: Cefiderocol MICs ranged from 0.5 to 1 mg/L for OXA-23-like non-producing <i>A. baumannii</i> strains and from 0.25 to >32 mg/L for OXA-23-like producers, using the broth microdilution method. Cefiderocol MIC<sub>90</sub> was 8 mg/L. Diameter of inhibition zone of cefiderocol ranged from 18 to 25 mm for OXA-23-like non-producers and from 15 to 36 mm for OXA-23-like producers, using the diffusion disk method. A large variability and a low reproducibility were observed during the determination of diameter inhibition zone. Molecular characterization showed that all isolates presented the ISAba1 genetic element upstream the <i>bla</i>OXA-51. Among OXA-23-like non-producers, four were <i>bla</i>OXA-58 positive and two were negative for all the resistance determinants analyzed. Conclusions: Cefiderocol showed in vitro antimicrobial activity against both carbapenem-susceptible and non-susceptible <i>A. baumannii</i> strains, although some OXA-23-like producers were resistant. Further clinical studies are needed to consolidate the role of cefiderocol as an antibiotic against MDR <i>A. baumannii</i>. |
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