The Antimicrobial Susceptibility Of Cefiderocol, A Novel Siderophore Cephalosporin, Against Clinically Isolated Carbapenem-Resistant Gram-Negative Bacilli From A Tertiary Care Hospital Of Punjab, Pakistan

INTRODUCTION: With the increasing prevalence of carbapenem-resistant isolates, it is imperative to identify and evaluate alternative treatment options to improve patient outcomes. Cefiderocol, a novel siderophore cephalosporin, is highly effective against these organisms and studies advocate its preferred use in clinical practice. A lack of local published material necessitated the present study, which is aimed to determine the antimicrobial susceptibility of cefiderocol against carbapenem-resistant Gram-negative bacilli isolated from various clinically significant specimens.

METHODS: This cross-sectional study was carried out in the Microbiology Laboratory of the Combined Military Hospital, Lahore, Pakistan over a duration of 6 months. The clinical samples from 145 patients with carbapenem-resistant isolates were tested for susceptibility against cefiderocol (CLSI 2022). The results were then compared across various subgroups.

RESULTS: The mean age of the patients was 45.8±15.8 years. There were 114 (78.6%) male and 31 (21.4%) female patients with a male-to-female ratio of 3.7:1. The majority of the samples comprised blood (n=40, 27.6%) followed by pus in 35 (24.1%) and non-directed bronchial lavage in 21 (14.5%) cases. Among the carbapenem-resistant isolates, carbapenem-resistant enterobacteriacae were more common and comprised 119 (82.1%) isolates, followed by pseudomonas aeruginosa in 26 (17.9%) cases. Cefiderocol susceptibility was observed in 133 (91.7%) carbapenem-resistant isolates. When compared, there was no statistically significant difference in cefiderocol susceptibility across various subgroups based on age (p-value=1.000), gender (p-value=0.720), type of clinical specimen (p-value=0.992), or carbapenem-resistant isolate (p-value=0.694).

CONCLUSION: Cefiderocol demonstrated a high susceptibility rate against carbapenem-resistant isolates, regardless of patient demographics and microbial organism, which underscores the potential of cefiderocol as an effective alternative treatment option for such cases in future clinical practice.