More and more highly multi-resistant pathogens
The proportion of bacteria that are also resistant to reserve antibiotics continues to rise. Experts recommend intensified monitoring.
The proportion of bacteria that are also resistant to reserve antibiotics continues to rise. Experts recommend intensified monitoring.
In 2024, the National Reference Center (NRC) for Gram-negative hospital pathogens at Ruhr University Bochum recorded a renewed increase in the number of samples submitted with multi-resistant bacteria. Over 10,000 samples were analyzed. The proportion of samples with carbapenemases - bacterial enzymes that can break down and thus inactivate the important reserve antibiotics of carbapenems - is worrying. This rose to 61.1 percent compared to 43.9 percent three years previously. “We can only urgently recommend intensified surveillance,” emphasizes Dr. Niels Pfennigwerth from the NRZ, which published its annual report in the Epidemiological Bulletin of the Robert Koch Institute on 15 May 2025. Such pathogens are life-threatening for patients being treated in hospital, as there are hardly any treatment options left.
Focus on carbapenemases
Since 2009, the NRZ has been offering free testing of multi-resistant Gram-negative bacterial strains on behalf of the Robert Koch Institute. Laboratories in Germany can send in clinical isolates that have been found to be resistant to important antibiotics in laboratory testing for further fine typing. The focus here is on the clarification of carbapenemases. These are bacterial enzymes that can cleave and thus inactivate the important reserve antibiotics of carbapenems.
Increase is real
In 2024, the NRZ was once again confronted with a significant increase in the number of submissions, meaning that over 10,000 bacterial isolates were ultimately analyzed in greater depth. As in the previous year, the number of carbapenemase detections also increased more than the number of submissions - the proportion of carbapenemase-producing isolates thus increased further and was now 61.1 percent of the isolates examined in Enterobacterales (such as Escherichia coli or Klebsiella pneumoniae). By comparison, this figure was only 43.9 percent in 2021. “According to our data, the increase in infections or colonizations with carbapenemase-producing bacterial strains in Germany is therefore real and not just due to an increase in the number of tests,” explains Niels Pfennigwerth.
The production of a carbapenemase is usually associated with resistance to the beta-lactam antibiotics commonly used clinically and drastically limits the available treatment options - especially when isolates produce more than one carbapenemase, which often complement each other in their efficacy spectra.
The problematic enzymes in detail
The most common carbapenemase in Enterobacterales continues to be OXA-48; this showed a significant increase in detections compared to the previous year. In contrast, the previously observed strong increase in NDM-1 stagnated in 2024, while significant increases were recorded for NDM-5, KPC-2, OXA-244 and VIM-1. In Pseudomonas aeruginosa and Acinetobacter baumannii, VIM-2 and OXA-23 were still the most frequently detected carbapenemases in the NRZ.
The researchers urgently recommend not only maintaining surveillance, but also intensifying it in order to obtain as accurate an overview as possible of developments and to take appropriate measures against the continuing spread. The experts are concerned that funding for the NRC from the Federal Ministry of Health is becoming less and less sufficient to fulfill its tasks.
Original publication
Niels Pfennigwerth, Sophie Möller, Jessica Eisfeld, Frederik Pankok, Sören G. Gatermann: Bericht des Nationalen Referenzzentrums für gramnegative Krankenhauserreger für das Jahr 2024, DOI: 10.25646/13143
Press contact
Dr. Niels Pfennigwerth
Nationales Referenzzentrum für gramnegative Krankenhauserreger
Abteilung für Medizinische Mikrobiologie
Ruhr-Universität Bochum
Tel.: +49 234 32 26938
E-Mail: niels.pfennigwerthruhr-uni-bochum "«@&.de