The bacterial displacement test: an in vitro microbiological test for the evaluation of intermittent catheters and urinary tract infection.

AIMS: Intermittent catheters (ICs) are commonly used in bladder management, but catheter-associated urinary tract infections (CAUTIs) remain challenging. Insertion tips may reduce the risk of CAUTIs by minimizing bacterial transfer along the urinary tract. However, there are few laboratory tests to evaluate such technologies. We describe the use of an adapted in vitro urethra agar model to assess bacterial displacement by ICs. METHODS AND RESULTS: Simulated urethra agar channels (UACs) were prepared with catheter-specific sized channels in selective media specific to the challenge organisms. UACs were inoculated with Escherichia coli and Enterococcus faecalis before insertion of ICs, and enumeration of UAC sections was performed following insertion. Four ICs were evaluated: Cure Catheter® Closed System (CCS), VaPro Plus Pocket™, Bard® Touchless® Plus, and SpeediCath® Flex Set. CCS demonstrated significantly reduced bacterial displacement along the UACs compared to the other ICs and was also the only IC with undetectable levels of bacteria toward the end of the UAC (representing the proximal urethra). CONCLUSION: The bacterial displacement test demonstrated significant differences in bacterial transfer between the test ICs with insertion tips, which may reflect their different designs. This method is useful for evaluating CAUTI prevention technology and may help guide future technology innovations.

Antimicrobial Activity of Silver-Containing Surgical Dressings in an In vitro Direct Inoculation Simulated Wound Fluid Model Against a Range of Gram-Positive and Gram-Negative Bacteria.

Background: Surgical site infections can lead to serious complications and present a huge economic burden. Established wound infections can be difficult to eradicate so preventative measures, including antimicrobial dressings, are advantageous. Materials and Methods: The antimicrobial activity of an ionic silver, ethylenediaminetetraacetic acid (EDTA) and benzethonium chloride-containing (ISEB) surgical cover dressing (SCD) was compared with two other silver-containing SCDs (silver sulfate and ionic silver carboxymethylcellulose [CMC]) and a non-silver-containing CMC SCD control using an in vitro model. The dressings were tested against a range of gram-positive and gram-negative bacteria found in wound environments, including antibiotic resistant strains, using a direct inoculation simulated wound fluid (SWF) model. Dressings were fully hydrated with SWF and inoculated with a final concentration of 1 × 106 colony forming units (CFU) per 10 microliter of the challenge organisms. Dressings were incubated at 35°C ± 3°C for up to seven days; total viable counts (TVCs) were performed to determine bacterial bioburden. Results: All challenge organism levels remained high for the CMC SCD control and silver sulfate SCD throughout the test period. A greater than 95% reduction in TVCs was observed by four hours for all challenge organisms for the ISEB SCD, with non-detectable levels (<70 CFU per dressing) reached within 24 hours and sustained throughout the test period. Antimicrobial activity was less rapid with ionic silver CMC SCD, with 9 of 11 challenge organisms reaching undetectable levels within 6 to 72 hours. Conclusions: A more rapid antimicrobial activity was observed for the ISEB SCD compared with other dressings tested within this in vitro model.

Trends in the Regulation of Per- and Polyfluoroalkyl Substances (PFAS): A Scoping Review.

Products containing per- and polyfluoroalkyl substances (PFAS) have been used for decades in industrial and consumer products. These compounds are persistent in the environment, bioaccumulative, and some are toxic to humans and other animals. Since the early 2000s, laws, policies, and regulations have been implemented to reduce the prevalence of PFAS in the environment and exposures to PFAS. We conducted a scoping literature review to identify how PFAS are regulated internationally, at the U.S. national level, and at the U.S. state level, as well as drivers of and challenges to implementing PFAS regulations in the U.S. This review captured peer-reviewed scientific literature (e.g., PubMed), grey literature databases (e.g., SciTech Premium Collection), Google searches, and targeted websites (e.g., state health department websites). We identified 454 relevant documents, of which 61 discussed the non-U.S. PFAS policy, 214 discussed the U.S. national-level PFAS policy, and 181 discussed the U.S. state-level PFAS policy. The drivers of and challenges to PFAS regulation were identified through qualitative analysis. The drivers of PFAS policy identified were political support for regulation, social awareness of PFAS, economic resource availability, and compelling scientific evidence. The challenges to implementing PFAS regulations were political limitations, economic challenges, unclear scientific evidence, and practical challenges. The implications for PFAS policy makers and other stakeholders are discussed.

Enhanced Performance and Mode of Action of a Novel Antibiofilm Hydrofiber® Wound Dressing.

Biofilm development in wounds is now acknowledged to be a precursor to infection and a cause of delayed healing. A next-generation antibiofilm carboxymethylcellulose silver-containing wound dressing (NGAD) has been developed to disrupt and kill biofilm microorganisms. This in vitro study aimed to compare its effectiveness against various existing wound dressings and examine its mode of action. A number of biofilm models of increasing complexity were used to culture biofilms of wound-relevant pathogens, before exposure to test dressings. Confocal microscopy, staining, and imaging of biofilm constituents, total viable counting, and elemental analysis were conducted to assess dressing antibiofilm performance. Live/dead staining and viable counting of biofilms demonstrated that the NGAD was more effective at killing biofilm bacteria than two other standard silver dressings. Staining of biofilm polysaccharides showed that the NGAD was also more effective at reducing this protective biofilm component than standard silver dressings, and image analyses confirmed the superior biofilm killing and removal performance of the NGAD. The biofilm-disruptive and silver-enhancing modes of action of the NGAD were supported by significant differences (p < 0.05) in biofilm elemental markers and silver donation. This in vitro study improves our understanding of how antibiofilm dressing technology can be effective against the challenge of biofilm.