Activity of cefiderocol on extensively drug-resistant Pseudomonas aeruginosa from burn wound infections in Mansoura, Egypt.

Background and objectives: Increased Pseudomonas aeruginosa antibiotic resistance limits treatment options and is associated with a higher level of mortality and mordacity. The purpose of this research was to identify class 1 and 2 integrons, carbapenemase, SHV, and TEM genes in extensively drug-resistant (XDR) P. aeruginosa isolated from infected burns and evaluate their in vitro cefiderocol activity.

Materials and methods: By using the disc diffusion method, the antimicrobial susceptibility of 110 P. aeruginosa isolates collected from infected burns were evaluated. XDR P. aeruginosa were screened phenotypically for carbapenemase and extended spectrum β-lactamases (ESBLs) production. Both MIC Test Strip and disc diffusion were employed to test the cefiderocol susceptibility. PCR was used to assess carbapenemase, SHV and TEM genes and integrons class 1 and 2.

Results: From the 110 P. aeruginosa, 54 isolates (49%) were XDR. TEM gene was detected in 35 isolates. Among XDR isolates, carbapenemase genes were detected in 31.5%, with NDM being predominant Thirty XDR isolates had class1 integrons. All isolates were sensitive to cefiderocol and its MIC₅₀/MIC₉₀ was 0.5/1.5mg/L (range 0.064-1.5mg/L).

Conclusion: Nearly half the P. aeruginosa isolates from burn infections were extensively drug-resistant. Cefiderocol's in vitro activity demonstrated that it is a promising therapy alternative for treating extensively drug-resistant P. aeruginosa in burn patients.