Emergence of antimicrobial resistance in New Caledonia: 20-year trends from laboratory-based surveillance (2005–2024)

Background Antimicrobial resistance (AMR) issues have emerged in New Caledonia, particularly involving methicillin-resistant Staphylococcus aureus (MRSA), and carbapenem-resistant Acinetobacter baumannii (CR-AB). However, a comprehensive overall picture is still required to guide an antimicrobial stewardship. Methods A prospective collection of antimicrobial susceptibility testing results was performed over a 20-year period (2005–2024) in the Territorial Hospital Center, the main hospital in New Caledonia. This surveillance encompassed 22 different pathogens and 28 antimicrobial agents, covering 157 pathogen-drug combinations. Resistance rates over time were analyzed using logistic models. A focus was placed on high-priority pathogens, including MRSA, CR-AB, vancomycin-resistant Enterococcus faecium , ceftazidime-resistant Pseudomonas aeruginosa , extended-spectrum β-lactamase Enterobacterales (ESBL-E), and carbapenemase-producing Enterobacterales (CPE). Multidrug-resistant (MDR) and possible extensively drug-resistant (pXDR) isolates were also identified and characterized. Findings Across 111,022 included isolates, emergences of resistance were observed, notably to penicillins, third-generation cephalosporins, tetracycline, and fusidic acid. Temporal resistance trends were described, along with outbreaks of MRSA and CR-AB, and the emergence of ESBL-E and CPE, representing 3.7% [95% CI: 3.5–3.8] (N = 2208), and 0.1% [95% CI: 0.1–0.2] (N = 85) of the 59,954 Enterobacterales isolates, respectively. Overall, 11% [95% CI: 10.8–11.1] were MDR and 0.6% [95% CI: 0.5–0.6] were pXDR. Interpretation Through trend analyses, this surveillance highlighted both the emergence and decline of AMR across diverse bacterial pathogens, helping inform which antibiotics may remain appropriate as first-line options and addressing the lack of data from Pacific Island settings.