Identification of Candida auris by PCR and assessment of biofilm formation by crystal violet assay

Standardizing biofilm quantification: harmonizing crystal violet absorbance measurements through extinction coefficient ratio adjustment

Precise quantification of biofilm is critical as the formation and persistence of biofilm have significant implications in the environmental, therapeutic and industrial contexts. The microtiter plate assay using crystal violet with 33% glacial acetic acid or 94-100% ethanol as the resolubilising agent is widely used for the categorisation of biofilms into weak, moderate and strong categories. But, the use of varying wavelengths for the measurement of biofilm resulted in discrepancies in categorisation across the studies due to the difference in the extinction coefficient of CV. This study emphasises the importance of measuring the biofilm at the absorbance maximum (λmax) of resolubilized CV, identified as 585 nm for 33% acetic acid and 580 nm for 94-100% ethanol. To address the challenge of harmonizing the results across studies, a method was developed to adjust the biofilm categorisation threshold based on the extinction coefficient ratios of CV at different wavelengths enabling consistent classification regardless of the wavelength used. Validation with E. coli and S. aureus demonstrated that the adjusted thresholds produced results similar to that obtained with the λmax. This standardised approach not only enables the researchers to obtain accurate and consistent results in the future studies, but also facilitates the comparison of previously published data on biofilm research, which is essential for the exploration of newer therapeutic strategies against biofilm related infections.

Enhancing Candida auris Surveillance in High-Risk Settings by Implementing a High-Throughput Molecular Assay on the Hologic Fusion Open Access Platform

Candida auris, a resilient pathogenic yeast with frequent multidrug resistance, presents a persistent challenge in healthcare settings. The timely identification of C. auris is crucial for infection control and prevention, especially in facilities facing unique hurdles, such as our institution, which serves four major hospitals and approximately 80% of the Texas inmate population. Understaffing, communal living, and financial constraints exacerbate infection control issues. To address common staff shortages, streamline testing services, and enhance testing efficiency, there was a pressing need for rapid and high-throughput detection of C. auris. This study presents the validation and utility of an assay implemented on the Hologic Fusion Open Access platform using samples collected from high-risk patients' axilla and groin areas, as well as environmental swab samples from patient rooms. Our assay complemented efforts to control C. auris outbreaks within our healthcare system, providing valuable insights into its presence within surveillance samples. This assay demonstrated the value of high-throughput molecular detection platforms in challenging healthcare environments by aiding infection preventionists in containing the spread of C. auris and preventing nosocomial infections. Our research contributes essential data on the suitability and performance of the Hologic Fusion Open Access platform for C. auris detection. These findings hold significant implications for enhancing surveillance and control measures in high-risk settings, making a significant impact on the field of infection control and prevention.

Is Silver Addition to Scaffolds Based on Polycaprolactone Blended with Calcium Phosphates Able to Inhibit Candida albicans and Candida auris Adhesion and Biofilm Formation?

Candida spp. periprosthetic joint infections are rare but difficult-to-treat events, with a slow onset, unspecific symptoms or signs, and a significant relapse risk. Treatment with antifungals meets with little success, whereas prosthesis removal improves the outcome. In fact, Candida spp. adhere to orthopedic devices and grow forming biofilms that contribute to the persistence of this infection and relapse, and there is insufficient evidence that the use of antifungals has additional benefits for anti-biofilm activity. To date, studies on the direct antifungal activity of silver against Candida spp. are still scanty. Additionally, polycaprolactone (PCL), either pure or blended with calcium phosphate, could be a good candidate for the design of 3D scaffolds as engineered bone graft substitutes. Thus, the present research aimed to assess the antifungal and anti-biofilm activity of PCL-based constructs by the addition of antimicrobials, for instance, silver, against C. albicans and C. auris. The appearance of an inhibition halo around silver-functionalized PCL scaffolds for both C. albicans and C. auris was revealed, and a significant decrease in both adherent and planktonic yeasts further demonstrated the release of Ag+ from the 3D constructs. Due to the combined antifungal, osteoproliferative, and biodegradable properties, PCL-based 3D scaffolds enriched with silver showed good potential for bone tissue engineering and offer a promising strategy as an ideal anti-adhesive and anti-biofilm tool for the reduction in prosthetic joints of infections caused by Candida spp. by using antimicrobial molecule-targeted delivery.