Researchers from Monash University have constructed novel antimicrobial surfaces with remarkable ability to reduce bacterial growth on medical tools, potentially reducing risks of health-care-associated infections like urinary tract infections (UTIs).
Urinary tract infections (UTIs) from urinary catheters are among the most prevalent forms of hospital-acquired infections, posing a considerable threat to global health, as declared by the World Health Organization (WHO). Claiming more than 13,000 lives each year, a large portion of UTIs is caused by bacteria. Hospitalised patients, in particular, are especially vulnerable to UTIs as the urinary catheters used during their stay are susceptible to contamination by superbugs, which are resistant to antimicrobials.
With this number in mind, it should come as no surprise that hospitals and researchers worldwide have been diligently working against the threat of UTIs and other hospital-related infections. One particular effort that has drawn considerable attention involves the remodelling of medical instrument surfaces.
Spearheaded by Dr Victor Cadarso from Monash University's Department of Mechanical and Aerospace Engineering and the Centre to Impact AMR, the team constructed surfaces with smooth, 3D micro features to reduce the likelihood of harmful bacteria adhering to surfaces in large quantities. Their latest innovation has broken away from traditional designs of sharp, cross-sectional styles of surfaces, innovating on their smooth, micro-topographical surfaces.
As the first study of its kind, the team has shown the promising potential of their 3D engineered surfaces to curb the formation of bacterial microcolonies, namely that of Escherichia coli (E. coli), Klebsiella pneumoniae and Pseudomonas aeruginosa. These three bacteria are infamous for causing UTIs linked to catheters. They physically modified the micro-architecture of instruments’ overlays to minimise infections. In comparison to chemical agents, making adjustments to these surfaces have proven to be more durable and effective to mitigate bacterial growth and antimicrobial resistance.
"Using E. coli as an example, we found bacterial cells that form on surfaces do so mostly on the sharp corners. By removing these sharp features, the bacteria can no longer colonise the surface as effectively. This same effect has been demonstrated for the two other pathogens in this study," stated Sara Ghavamian, from the Monash Department of Mechanical and Aerospace Engineering, who created these surfaces.
The researchers went on to examine the performance of their latest creation and concluded that the surfaces were successful in decreasing bacterial adherence and biofilm formation. One of their anti-microbial surfaces, also known as P01, reduced the attachment of E. coli, K. pneumoniae, and P. aeruginosa by 55 per cent, 69 per cent and 68 per cent, and decreased the formation of microcolonies by 53 per cent, 77 per cent and 66 per cent, respectively.
Through their study, they have also discovered that present architectures of medical instruments with sharp corners and conventional micropatterned finishes are severely limited in offering protection against bacteria. In fact, their structure provides perfect hiding spots for bacteria to safeguard against moving fluids that could potentially detach them.
To overcome these obstacles, they have chosen to eliminate these corners and replace them with their 3D engineered micro-topographies, which utilise different heights and smooth curved cross-sections. Their innovative style has been proven to effectively pre-empt bacterial attachment, microcolony assembly and biofilm formation for the three tested bacteria.
"Opposite the conventional sharp micropatterned surfaces, our smooth design demonstrated a simultaneous decrease in both the number of bacterial attachment and microcolony formation compared to the standard flat surfaces," Sara said. "Developing strategies to prevent the bacterial colonisation of surfaces, such as catheters, without requiring antimicrobial drugs or chemicals is critical to stop biofilm formation and the potential spread of harmful diseases."
Through their innovative creation, the researchers have underscored the need to renew outdated strategies to tackle the ever-growing threat of bacterial contamination, specifically on surfaces of medical instruments like catheters. Their unconventional, chemical-free solution to mitigate biofilm formation and spread of infectious diseases is expected to lay the groundwork for future improvements in antimicrobial technologies.
Source: Ghavamian et al. (2021). Three-Dimensional Micropatterning Deters Early Bacterial Adherence and Can Eliminate Colonization. ACS Applied Materials & Interfaces.