Multidrug-resistant bacteria cooperate to reduce the impact of antibiotics: study

By Nick Paul Taylor, The Science Advisory Board contributing writer

February 14, 2023 -- Two of the most dangerous multidrug-resistant pathogens work together to nullify antibiotics, suggesting physicians need to determine if both bacteria are present before selecting a treatment regimen.

The study, details of which were published in Nature Communications, examined interactions between Acinetobacter baumannii and Klebsiella pneumoniae strains co-isolated from a human lung infection. A. baumannii is one of three pathogens that the World Health Organization sees as a critical priority. Both bacteria are part of the group of six highly virulent, resistant pathogens known by the acronym ESKAPE.

Using transcriptomic, phenomic, and phenotypic assays, researchers at Australia's Macquarie University and University of Newcastle sought to understand why dual infections with the bacteria are associated with increased antibiotic resistance and mortality rates.

Analysis of dual-species co-culture biofilms revealed that each bacteria helps the other. K. pneumoniae cross-feeds A. baumannii its byproducts of sugar fermentation, namely ethanol and lactate, and thereby supports the growth of the other pathogen. At the same time, A. baumannii releases enzymes that break certain antibiotics. The release of cephalosporinases enabled K. pneumoniae to tolerate higher levels of antibiotics than it can survive in the absence of A. baumannii.

The findings have implications for the diagnosis and treatment of infections with the two pathogens, as Macquarie University's Lucie Semenec explained in a statement. "This research is significant because diagnostic methods commonly look for the most dominant pathogen and therefore treatment is targeted at that," Semenec said. "New drugs now can be informed in future research by the molecular mechanisms we find in this work."

Only considering the predominant infecting microorganism when diagnosing bacterial infections enables physicians to focus treatment on the most prevalent, and therefore potentially the most problematic, pathogen. However, the work of Semenec and her collaborators suggests limiting the diagnosis to the predominant microorganism may result in suboptimal treatment.

If A. baumannii is predominant, its growth rate will vary depending on whether K. pneumoniae is present or not. Knowing that A. baumannii has a growth advantage could help optimize treatment. Similarly, the discovery of A. baumannii in a patient with a K. pneumoniae infection will reveal that the efficacy of cephalosporins such as cefotaxime may be reduced.

The two pathogens are both involved in a range of respiratory, urinary tract, and blood infections. By determining if both bacteria are present, physicians may be able to provide a more effective treatment and minimize the risk that cross-feeding and cross-protection will enable pathogenic biofilms to survive in the presence of high concentrations of antibiotics.

Researchers discover new form of undetectable antimicrobial resistance
Australian researchers have discovered a new form of antimicrobial resistance that is undetectable using traditional testing methods. Their findings may...
Can vaccine resistance be predicted with test samples?
The likelihood of SARS-CoV-2 developing resistance to COVID-19 vaccines currently under development can be determined using repurposed blood and nasal...
Machine learning helps identify antimicrobial-resistant bacteria
A new graphical user interface-driven, machine learning-based approach has successfully identified antimicrobial resistance genes for gram-positive and...
Artificial intelligence helps researchers find new antibiotics
To address antibiotic resistance, researchers have developed a machine-learning approach that can search millions of known chemicals to find new...
New CRISPR system efficiently battles antibiotic resistance
Researchers from the University of California San Diego have developed a brand new CRISPR-based gene-drive system that dramatically increases the efficiency...

Copyright © 2023

Science Advisory Board on LinkedIn
Science Advisory Board on Facebook
Science Advisory Board on Twitter