In Vitro Activity of Ceftazidime-Avibactam Against Enterobacteriaceae and P. aeruginosa Isolated at the Ibn Rochd University Hospital of Casablanca.

BACKGROUND

The aim of this study is to determine the in vitro activity of ceftazidime-avibactam (CZA) on Entero-bacteriaceae and P. aeruginosa strains isolated in the bacteriology-virology laboratory of the Ibn Rochd University of Casablanca.

METHODS

This is a prospective descriptive longitudinal study conducted from May 28 through June 25, 2022, on Enterobacteriaceae and P. aeruginosa isolated from diagnostic samples received at the Bacteriology-Virology and Hospital Hygiene Laboratory of the Ibn Rochd University Hospital of Casablanca. The isolation and identification of the strains were carried out using standard bacteriological techniques. The study of sensitivity to ceftazidime-avibactam was done by diffusion susceptibility testing on agar medium according to EUCAST 2022 recommendations.

RESULTS

During the study period, 271 strains of Enterobacteriaceae were isolated. The sensitivity rate to ceftazidime-avibactam was 91% vs. 74% for ceftazidime alone. R. terrigena was the most resistant strain to CZA with a rate of 69%, followed by E. cloacae (14%), then K. pneumoniae (6%), and finally E. coli (5%). Among the strains isolated, 24% (n = 66) produced ESBL, of which 29% (n = 19) were resistant to CZA, and 10.7% (n = 29) were re-sistant to imipenem, including 44, 8% (n = 13) that were resistant to imipenem and CZA. Regarding P. aeruginosa, 92 strains were isolated. The CZA resistance rate was 33.6% (n = 31). Among the strains isolated, 30.4% (n = 29) were resistant to imipenem, of which 82.7% (n = 24) were resistant to CZA.

CONCLUSIONS

The in vitro evaluation of the ceftazidime-avibactam activity on the strains isolated, mainly: E. Coli, K. Pneumoniae, and E. Cloacae, showed a good inhibitory activity of this molecule which can constitute a therapeutic alternative for the treatment of infections due to these microorganisms.