Analysis of Antimicrobial Resistance Genes (ARGs) in Enterobacterales and A. baumannii Clinical Strains Colonizing a Single Italian Patient.

The dramatic increase in infections caused by critically multidrug-resistant bacteria is a global health concern. In this study, we characterized the antimicrobial resistance genes (ARGs) of , , and isolated from both surgical wound and rectal swab of a single Italian patient. Bacterial identification was performed by MALDI-TOF MS and the antimicrobial susceptibility was carried out by Vitek 2 system. The characterization of ARGs was performed using next-generation sequencing (NGS) methodology (MiSeq Illumina apparatus). , and were resistant to most β-lactams and β-lactam/β-lactamases inhibitor combinations. strain was susceptible only to colistin. The presence of plasmids (IncN, IncR, IncFIB, ColRNAI and Col (MGD2)) was detected in all Enterobacterales but not in strain. The IncN plasmid and gene were found in , and , suggesting a possible transfer of this gene among the three clinical species. Conjugation experiments were performed using (1 isolate), (2 isolates) and (2 isolates) as donors and J53 as a recipient. The gene was identified by PCR analysis in all transconjugants obtained. The presence of four different bacterial species harboring resistance genes to different classes of antibiotics in a single patient substantially reduced the therapeutic options.