Niels Pfennigwerth (Bochum / DE), Martina Cremanns (Bochum / DE), Jessica Eisfeld (Bochum / DE), Jörg B. Hans (Bochum / DE; Berlin / DE), Agnes Anders (Bochum / DE), Sören G. Gatermann (Bochum / DE)
Question:
Multidrug-resistance in Enterobacterales, Pseudomonas aeruginosa and Acinetobacter baumannii is of utmost therapeutic importance since hardly any innovative antimicrobial drug against gramnegative bacteria will be introduced within the next years. Among all resistance mechanisms the spread of carbapenemases is the most worrisome. However, the correct identification of carbapenemases is still challenging and molecular epidemiology of carbapenemases is required.
Methods:
The German National Reference Centre for Multidrug-Resistant Gramnegative Bacteria offers the free service of carbapenemase detection in bacterial isolates with elevated carbapenem MICs. All isolates are tested by a wide array of phenotypic and molecular methods. A bioassay based on cell-free extracts and WGS methods allow the detection of still unknown β-lactamases.
Results:
A total of 8.319 isolates were investigated for carbapenemases at the National Reference Centre in 2023 until November 29th. Carbapenemases were found in 3.513 Enterobacterales strains, 520 of P. aeruginosa and 375 of A. baumannii. The most frequent carbapenemases in Enterobacterales were OXA-48 (n = 612), NDM‑1 (n = 481) and KPC-2 (n = 442), which were also found in various combinations, e.g. NDM-1/OXA-48 (n = 125). Other enzymes like NDM-4, OXA-232 or GIM‑1 were found in less than 60 isolates each. In P. aeruginosa, VIM-2 was the most frequent carbapenemase (n = 291), followed by NDM-1 (n = 61). OXA-23 was again the most frequent carbapenemase in A. baumannii (n = 220), followed by OXA-72 (n = 95). NDM-1, OXA-58 and others were found in less than 10 isolates each.
Conclusions:
A large variety of different carbapenemases is detected in Germany, especially in Enterobacterales. The molecular epidemiology in Germany still significantly differs from observations made in other countries like Greece, Italy or the USA with a predominance of OXA-48 in Enterobacterales. Compared to previous years, the number of NDM-1 detections remained high. Furthermore, detection of NDM-5 and OXA-244 showed a significant increase compared to 2022.