Multipathogen antimicrobial resistance in a Romanian tertiary-care hospital: a retrospective antibiogram analysis,...

Routine microbiology data can show not only isolated resistance events but also the wider hospital ecology in which antimicrobial resistance (AMR) emerges. We analyzed the complete January-July 2025 antibiogram export from a Romanian tertiary-care hospital, along with a targeted extended-testing file. The scope was deliberately broader than a single-organism carbapenem-resistant Klebsiella pneumoniae analysis. We performed a retrospective descriptive analysis using 3,270 antibiogram records from 3,012 patient identifiers. Organisms, sample types, resistance labels, and extended-test results were extracted from laboratory text fields. Organism occurrences within polymicrobial reports were counted separately to describe the full pathogen spectrum. The dataset contained 4,039 organism occurrences. Enterobacterales were the largest group, followed by Gram-positive cocci, non-fermenting Gram-negative bacilli, and yeasts. Escherichia coli and K. pneumoniae were the most frequent Enterobacterales, and clinically relevant resistant organisms were also identified among Pseudomonas aeruginosa, Enterobacter cloacae complex, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecium and Candida species. The extended-testing file contained 100 organism occurrences from 85 patient identifiers, mainly extensively drug-resistant Gram-negative isolates. Cefiderocol testing corresponded predominantly to K. pneumoniae, P. aeruginosa and Acinetobacter baumannii complex, whereas aztreonam/avibactam was concentrated mainly in extensively drug-resistant Enterobacterales, especially K. pneumoniae. The data support a multipathogen AMR interpretation: carbapenem-resistant Enterobacterales, non-fermenters, resistant Gram-positive cocci and yeasts coexist in the same hospital ecology. Empirical therapy, infection-control actions and stewardship decisions should be guided by syndrome, sample source, prior colonization and local species-level resistance patterns.