Two decades of ESKAPE pathogens: Longitudinal analysis of antibiotic resistance trends between 2002 and 2024 in a Hungarian clinical centre.

This retrospective study analysed 14,625 isolates of the six major hospital-associated 'ESKAPE' pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) collected between 2002 and 2024 in a Hungarian tertiary-care centre. Antimicrobial resistance was assessed using the antibiotic resistance index (ARI), multidrug resistance (MDR) ratios, and resistance instability index (RII). A. baumannii and E. faecium showed the highest resistance burdens and instability. Age showed a significant monotonic association with resistance (Spearman r = 0.88), with peaks in infants, middle-aged women, and the elderly. Species-specific age trends varied, with a negative correlation seen in Enterobacter spp. Hierarchical clustering grouped pathogens by resistance trajectory rather than taxonomy. Pairwise resistance distances confirmed divergence between Gram-positive and Gram-negative species. Resistance to aminoglycosides and sulphonamides showed the highest year-to-year variability, as quantified by the RII, particularly in A. baumannii and E. faecium. Vector autoregressive (VAR) modelling predicted continued MDR increases in these species. A strong correlation was found between ARI and RII (Pearson r = 0.85, p = 0.032). These findings underscore the importance of integrating resistance magnitude and volatility in surveillance.