Bacterium extremely resistant to drugs spreading in hospitals

A new study found that a common bacterium responsible for chest infections and sepsis in sick people, and which does not respond to the most potent antibiotics, spreads through hospital contacts.

The bacteria, called Klebsiella pneumoniae, spreads in European hospitals and some strains can not be controlled, even by carbapenems, a category of antibiotics hitherto reserved as the last line of treatment of resistant infections. Such strains are called extremely drug resistant bacteria (XDR). The main affected patients are the very young and the very old, as well as those whose immune system is weakened.

Klebsiella pneumoniae bacterium in the respiratory tract, 3D illustration showing the lashes of the respiratory tract and bacteria. Image credit: Kateryna Kon / Shutterstock

The study was conducted by the Genomic Agents Monitoring Center of the Wellcome Sanger Institute of the University of Friborg. They examined 1,700 samples of the isolated bacterium from patients in 32 countries in nearly 250 hospitals. After sequencing the genome, they concluded that the XDR strains had resulted in about 350 deaths in 2007, but that in 2015, they had increased to over 2000, or six times more. This clearly shows that carbapenems are no longer reliable in the fight against antibiotic resistance, so that doctors have few other defenses.

The investigation of the family Enterobacteriaceae, to which Klebsiella pneumoniae belongs, is remarkable in size, outnumbering all previous surveys, and marks the beginning of intensive and widespread monitoring of carbapenem resistance in Europe. Sequencing of the genome has led to the discovery of certain genes encoding the carbapenemase enzymes that can break these antibiotics. Scientists have recently discovered that some bacteria carry one or more of these genes and these have spread rapidly, probably due to the overuse of antibiotics in some hospitals. The reason is that when other antibiotics kill the bacteria, the remaining XDR bacteria take over the head of the infections.

Current research has shown that almost 70% of XDR bacteria isolated from patients belong to four strains with their derivatives. In addition, the greater the resistance, the easier their spread in hospitals. They concluded that more than half of the XDR strains spread between patients in the same hospital or between patients and other contacts.

The first author, Sophia David, said: "The One Health approach to antibiotic resistance focuses on the spread of pathogens by humans, animals and the environment, including hospitals. But in the case of carbapenem resistant Klebsiella pneumoniaeOur results imply that hospitals are the main facilitator of transmission – more than half of the samples carrying a carbapenemase gene were closely related to the others collected in the same hospital, suggesting that the bacterium spreads from person to person primarily. in the hospital. "

Not only has antibiotic resistance been observed in related bacteria in several hospitals in the same country, but not across national borders, suggesting that they are being spread by health facilities. health. The solution would be to put in place stricter infection control measures, including moving patients from one hospital to another.

The researchers also highlighted the high levels of hospital hygiene. The co-author, Hajo Grundmann, said: "We are optimistic: with good hospital hygiene, which includes the early identification and isolation of patients carrying this bacteria, we can not only delay the spread of these pathogens, but also control them successfully. This research highlights the importance of infection control and ongoing genomic surveillance of antibiotic-resistant bacteria to enable us to rapidly detect new resistant strains and combat the spread of antibiotic resistance. They also contributed to the figure of 21 for the number of single nucleotides. polymorphisms to be detected for the optimal identification of a cluster from a single hospital and to track the international spread of these deadly bacteria.

Researchers are already mapping the second enterobacteria survey and putting all of their data in the public domain using MicroReact, an online tool developed by the Genomic Agent Monitoring Center. We hope this will help detect antibiotic resistance that is spreading in various harmful bacteria and the appearance of new forms. A key aspect of the ongoing work is its use of genomic sequencing, which allows them to track new antibiotic resistance strains through their genomes rather than by older, less precise measures. Another researcher, David Aanensen, comments: "Currently, new strains are evolving almost as fast as we can sequence them. The goal of establishing a robust network of Genome Sequencing Centers will enable health systems to monitor the spread of these bacteria and their evolution much more quickly. "