Device simulates natural conditions to grow biofilms and test their antibiotic susceptibility more accurately

Biofilms are complex microbial communities that adhere to a surface and encase themselves in a viscous matrix, making them highly resistant to antibiotics and the immune system. This makes biofilms responsible for many chronic infections, such as those affecting cystic fibrosis patients and individuals with COPD or those caused by catheters or prosthetic devices.

The global increase in antibiotic resistance intensifies the need for tools to accurately predict which treatments will be effective. Researchers at the Institute for Bioengineering of Catalonia (IBEC) have created XpertBiofilm, a device that simulates natural conditions to grow biofilms and test their antibiotic susceptibility more accurately.

XpertBiofilm allows biofilms to be grown under continuous, controlled liquid flow, similar to what bacteria experience in the human body, such as in lung mucus, blood, or urine. Most laboratory systems for studying biofilm formation use static plates with still culture mediums, but in the body, bacteria rarely grow in a still environment.

Instead, they are constantly subjected to friction due to fluid flow, known as shear stress. XpertBiofilm's design replicates this flow in a controlled manner, using a removable coverslip that forms the biofilm. The biofilm can then be analyzed with a microplate reader, eliminating the need for specialized microscopes and allowing for more accessible and streamlined observation.

This tool is particularly relevant in cystic fibrosis and COPD, where mucus is thicker and more viscous than usual, and bacteria encounter low shear stress conditions. In these cases, XpertBiofilm has shown that higher flow rates lead to more biofilm biomass formation, which helps explain why bacteria adhere strongly to airways in cystic fibrosis patients, reducing the ability to clear bacteria and leading to chronic infections.

By reproducing the flow conditions bacteria experience in the body, XpertBiofilm allows researchers to better predict antibiotic effectiveness more accurately. The device can also assess the effectiveness of antibiotics against biofilms using patient samples directly from cystic fibrosis patients, without the need for prior isolation of a single bacterial strain.

This direct application of patient samples enables faster antibiotic susceptibility testing tailored to each patient, which is especially valuable in chronic infections like cystic fibrosis. However, the study's authors note that this is a laboratory-based validation using a limited number of bacterial strains and patient samples.

Further validation with a larger number of clinical samples and bacterial species is needed to confirm its usefulness in routine clinical practice.