The combination of three synthetic AMPs (PD4-RW3-RW4) can be used to inhibit biofilm formation by S. epidermidis to enhance PC safety. However, further investigation is needed to improve their activity against mature S. epidermidis biofilms.

The anti-biofilm activity of chlorhexidine-gluconate plus isopropyl alcohol can be greatly enhanced by L. multifida oil or linalool. Therefore, these components could potentially be used to improve blood donor skin disinfection.

Background and Objectives Staphylococcus epidermidis is a predominant contaminant of platelet concentrates (PCs), outcompeting other skin flora bacteria such as Staphylococcus capitis. The accumulation‐associated protein (Aap), encoded by the aap gene, is involved in formation of bacterial aggregates (biofilms) in S. epidermidis and is absent in S. capitis. In this study, the role of S. epidermidis aap in enhancing biofilm formation and conferring an advantageous growth in PCs was investigated. Materials and Methods Biofilm formation assays of S. epidermidis 1457, S. epidermidis 1457∆aap, S. capitis 517 and S. capitis 517 carrying S. epidermidis aap (S. capitis 517/pRBaap) were performed in glucose‐supplemented trypticase soy broth (TSBg) and PCs. Additionally, competition assays with paired cultures (1:1 ratio) of S. epidermidis and S. capitis strains were seeded in PCs, followed by determination of viable counts of each organism at the end of PC storage. Results Staphylococcus epidermidis aap had no effect on biofilm formation in TSBg. By contrast in PCs, S. epidermidis 1457 showed higher biofilm formation than S. epidermidis 1457∆aap (P < 0·05). Biofilm formation was also enhanced in S. capitis 517/pRBaap compared to S. capitis 517 (P = 0·054). Competition assays showed that S. epidermidis 1457 outcompeted S. capitis 517, and importantly, S. capitis 517/pRBaap outcompeted S. capitis 517 and S. epidermidis 1457∆aap. Conclusion This study demonstrated that S. epidermidis aap plays a role in biofilm formation in PCs conferring an advantageous proliferation to skin flora bacteria in this milieu. The molecular mechanisms of action of Aap merit further investigation.

Background: Bacterial antibiotic resistance (AR) is a primary public health concern. In 2017, the Saudi National Action Plan (SNAP) implemented several strategies to overcome AR. Here, to better understand the effectiveness of that plan, we evaluated the rates of AR, extended-spectrum beta-lactamase (ESBL) positivity, and multi-drug resistance (MDR) among gram-negative bacteria in a private Saudi hospital. Methods: This retrospective study included all patients with a confirmed diagnosis of gramnegative bacterial infection from January 2017 to December 2019. Identification of bacterial strains was performed using VITEK 2 ID-GNB cards, while AR, ESBL, and MDR were determined using AST-No. 12 cards, both used as recommended by the manufacturer. Cards were loaded into a VITEK 2 system for examination. Results: A total of 4760 isolated gram-negative bacteria were collected. The most isolated organism was Escherichia coli, with 2585/4760 (54.30%) strains, and the least was Providencia stuartii, with 55/4760 (1.16%) strains. A total of 1328/4760 (27.90%) clinical isolates were ESBL-positive, and 851/4760 (17.88%) possessed MDR. Escherichia coli was also the most frequently isolated as having ESBL activity and MDR, with 772/1328 (58.13%) and 292/851 (34.31%) isolates, respectively. Between 2017 and 2019, the rates of ESBL and MDR were significantly reduced (p < 0.05) for most bacteria, except for Salmonella species, which showed increased resistance to antibiotics. Conclusion: Our findings revealed that the rates of AR, ESBL, and MDR reduced over time, which suggests the SNAP is effective at overcoming AR risk.