Favourable effect of clavulanic acid on the minimum inhibitory concentrations of cefixime and ceftibuten in ESBL-producing Escherichia coli and Klebsiella pneumoniae

• Published in: Journal of global antimicrobial resistance. 2024-09, Vol.38, p.212-215
• Main Authors: Martinez-Guerra, Bernardo Alfonso, Xancal-Salvador, Luis Fernando, Esteban-Kenel, Veronica, Tello-Mercado, Andrea Carolina, Bobadilla-del-Valle, Miriam, Sifuentes-Osornio, Jose, Ponce-de-Leon, Alfredo, Gonzalez-Lara, Maria Fernanda
• Format: Article
• Language: English
• Subjects: Anti-Bacterial Agents - pharmacology; beta-Lactamases - metabolism; Cefixime; Cefixime - pharmacology; Ceftibuten; Ceftibuten - pharmacology; Cephalosporins - pharmacology; Clavulanic acid; Clavulanic Acid - pharmacology; Enterobacteriaceae; Escherichia coli - drug effects; Escherichia coli - enzymology; Escherichia coli Infections - drug therapy; Escherichia coli Infections - microbiology; Extended spectrum beta-lactamase; Humans; Klebsiella Infections - drug therapy; Klebsiella Infections - microbiology; Klebsiella pneumoniae - drug effects; Klebsiella pneumoniae - enzymology; Microbial Sensitivity Tests
• ISSN: 2213-7165; 2213-7173; 2213-7173
• DOI: 10.1016/j.jgar.2024.06.008

•Clinical use cephalosporins combined with clavulanate has been scarcely described.•Oral cephalosporin/clavulanate combinations must be studied.•Clavulanate lowers MIC of cefixime/ceftibuten in ESBL-producing Enterobacterales.•Oral cephalosporin/clavulanate could prove a useful ESBL treatment strategy. The use of cephalosporins combined with clavulanate for the treatment of ESBL-harbouring Enterobacteriaceae has been scarcely described. We aimed to describe the effect of different concentrations of clavulanate in the MIC of cefixime and ceftibuten of ESBL-producing Escherichia coli and Klebsiella pneumoniae. ESBL-producing E. coli and K. pneumoniae isolates were studied. Fixed concentrations of cefixime and ceftibuten (ranges of 32–0.25 and 64–0.5 ng/ml, respectively) were used. Combinations of cefixime/clavulanate and ceftibuten/clavulanate in different ratios (1:0, 1:1, 2:1, 4:1, 8:1, 16:1, 32:1) were tested. MIC were determined by broth microdilution. A total of 6 ESBL-producing E. coli, 6 ESBL-producing K. pneumoniae and 2 control E. coli were tested. When different quantities of clavulanate were added to cefixime and ceftibuten, greater than two-fold decreases in the MIC were observed. When testing the 1:1 cefixime/clavulanate ratio, 10/12 isolates were susceptible. When the ratios 2:1, 4:1, 8:1 and 16:1 were tested, susceptibility was noted for 9/12, 8/12, 4/12 and 5/12 isolates, respectively. Only 2/12 K. pneumoniae isolates were susceptible when the ratio 32:1 was tested. When testing ceftibuten/clavulanate, all isolates remained susceptible across all experiments. Clavulanic acid has a favourable effect in reducing the MIC of cefixime and ceftibuten in isolates of ESBL-producing E. coli and K. pneumoniae. Combining clavulanate with ceftibuten or cefixime could be a useful treatment strategy.