Characterization of imipenem-resistant Acinetobacter baumannii and Pseudomonas aeruginosa clinical isolates in a Moroccan hospital.

Acinetobacter baumannii and Pseudomonas aeruginosa are two pathogens with an important power of adaptation to antibiotics thus, both pose a real public health problem. Our study investigated epidemiological characteristics, antibiotic sensitivity profile and resistance genes of imipenem resistant A. baumannii and P. aeruginosa. This was a retrospective study carried out in the bacteriology laboratory of Mohammed V military training hospital, spanning from January 2018 to April 2021. Antibiotic susceptibility was studied by Mueller Hilton agar diffusion method with OXOID® type antibiotic discs and interpreted according to the recommendations of EUCAST 2021. Carbapenemase detection was performed by CarbaNP-test®. The molecular study was performed using conventional PCR. During the study period, we collected 1,072 imipenem-resistant isolates namely, 820 A. baumannii and 252 P. aeruginosa. The molecular study showed that out of 108 A. baumannii isolates 102 carried the bla OXA-51 and 100 isolates carried the bla OXA-23 gene. The coexistence of bla OXA-23 and bla NDM genes was detected in only 4 isolates. Altogether 50% of P. aeruginosa strains carried bla VIM-2. All investigated A. baumannii and P. aeruginosa strains were colistin susceptible in this study. Multiresistant bacterial infections are associated with longer hospitalization, higher hospital costs and higher mortality rates. Therefore, a collective action including the different actors of the healthcare system is necessary.