Catheter Colonization and Abscess Formation Due to Staphylococcus epidermidis with Normal and Small-Colony-Variant Phenotype Is Mouse Strain Dependent

Coagulase-negative staphylococci (CoNS) form a thick, multilayered biofilm on foreign bodies and are a major cause of nosocomial implant-associated infections. Although foreign body infection models are well-established, limited in vivo data are available for CoNS with small-colony-variant (SCV) phenotype described as causative agents in implant-associated infections. Therefore, we investigated the impact of the Staphylococcus epidermidis phenotype on colonization of implanted PVC catheters and abscess formation in three different mouse strains. Following introduction of a catheter subcutaneously in each flank of 8- to 12-week-old inbred C57BL/6JCrl (B6J), outbred Crl:CD1(ICR) (CD-1), and inbred BALB/cAnNCrl (BALB/c) male mice, doses of S. epidermidis O-47 wild type, its hemB mutant with stable SCV phenotype, or its complemented mutant at concentrations of 106 to 109 colony forming units (CFUs) were gently spread onto each catheter. On day 7, mice were sacrificed and the size of the abscesses as well as bacterial colonization was determined. A total of 11,500 CFUs of the complemented mutant adhered to the catheter in BALB/c followed by 9,960 CFUs and 9,900 CFUs from S. epidermidis wild type in BALB/c and CD-1, respectively. SCV colonization was highest in CD-1 with 9,500 CFUs, whereas SCVs were not detected in B6J. The minimum dose that led to colonization or abscess formation in all mouse strains was 107 or 108 CFUs of the normal phenotype, respectively. A minimum dose of 108 or 109 CFU of the hemB mutant with stable SCV phenotype led to colonization only or abscess formation, respectively. The largest abscesses were detected in BALB/c inoculated with wild type bacteria or SCV (64 mm2 vs. 28 mm2). Our results indicate that colonization and abscess formation by different phenotypes of S. epidermidis in a foreign body infection model is most effective in inbred BALB/c followed by outbred CD-1 and inbred B6J mice

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries

Post-operative view of mice, abscesses, and biofilm staining of catheters.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036602#pone-0036602-g001" target="_blank">Figure 1A</a>, I: Implantation of a 1-cm long sterile PVC catheter segment subcutaneously subsequent to anesthetizing, shaving, and making a small incision in each flank of the mouse. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036602#pone-0036602-g001" target="_blank">Figure 1A</a>, II. Abscess formation in a mouse 7 days post inoculation with <i>S. epidermidis</i> O-47. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036602#pone-0036602-g001" target="_blank">Figure 1B</a>: Subcutaneous abscesses from mice 7 days after inoculation of <i>S. epidermidis</i> O-47; III) BALB/c mouse with a dose of 10⁷, IV) CD-1 mouse with a dose of 10⁸, and V) B6J mouse with a dose of 10⁹ CFUs and safranin-stained PVC catheters from BALB/c mice 7 days after inoculation of <i>S. epidermidis</i> O-47; VI) dose of 10⁷, VII) dose of 10⁸, and VIII) dose of 10⁹ CFUs.</p