In vitro sulbactam/avibactam synergy against carbapenem-resistant Acinetobacter baumannii from hospitals in Peru

Huerto-Huánuco R.; Quispe-Hualpa Y.; Alonso C.A.; Oporto-Llerena R.; Soza G.; Surichaqui-Cerrón Z.; Valera-Krumdieck C.; Castañeda L.; Pons M.J.; Sáenz Y.; Ruiz J.; Castillo A.K.; Ramos-Chirinos M.; Rojas-Jaimes J.; Tarraga Gonzales D.; Nuñez Infanzón E.; Gonzales P.; Pollack L.; Alcedo K.; Villegas Quispe W.; Salvador-Luján G.; Cuaresma E.; Luque N.; Casapia M.; Celis J.C.; Briones A.; Arteaga-Livias K.; López M.; Rojo-Bezares B.; Toledano P.; Gomez A.C.; Zevallos A.; Pinto J.; Tutaya K.Z.; Salcedo M.V. · JAC-Antimicrobial Resistance (2025) · DOI: 10.1093/jacamr/dlaf217

Resumen

Objectives To evaluate the synergistic activity of ampicillin/sulbactam plus ceftazidime/avibactam in a collection of carbapenem-resistant Acinetobacter baumannii (CR-Ab) from different regions in Peru. Materials and methods One hundred and eighty-four CR-Ab isolates were included in this study. They were identified by amplification of bla OXA-51 and confirmed by MALDI-TOF (matrix-assisted laser desorption ionization time of flight) mass spectrometry and 16S rRNA sequencing. Susceptibility to ampicillin/sulbactam and carbapenems was determined by the disc diffusion method. Synergy was assessed using discs containing ampicillin/sulbactam and ceftazidime/avibactam. The EDTA-disc synergy test was used to screen metallo-β-lactamase-producing isolates, and in isolates showing synergy, the presence of bla NDM was confirmed by PCR. Statistical analysis was performed using Fisher’s exact test. Results High levels of resistance to ampicillin/sulbactam were found in the study. Thus, 1.1% (2/184), 11.4% (21/184) and 87.5% (161/184) of isolates were classified as susceptible, intermediate and resistant to ampicillin/sulbactam, respectively. Synergistic activity was observed in 97.2% of the non-susceptible CR-Ab isolates. The presence of metallo-β-lactamase producers (all bla NDM) was observed in three isolates (1.6%). Conclusions These findings demonstrate high levels of synergistic activity between ampicillin/sulbactam and ceftazidime/avibactam and their potential use as a treatment for CR-Ab. © The Author(s) 2025. Published by Oxford University Press on behalf of British Society for Antimicrobial Chemotherapy.

Instituciones: Universidad Científica del Sur; Universidad Privada del Norte