Aims This study aimed to identify the most effective antimicrobial agent from a selection of essential oils (EO) and investigate its bactericidal properties against Pseudomonas aeruginosa. Methods and Results The disc diffusion assay and minimal inhibitory/bactericidal concentration tests were used to identify antimicrobial potential. Several oils exhibited antimicrobial effects at concentrations as low as 0·03% (v/v). Significantly, cinnamon (Cinnamomum zeylanicum) bark EO exhibited a broad‐spectrum activity against Gram‐negative and Gram‐positive bacteria and showed bacteriostatic and bactericidal effects against P. aeruginosa PAO1 at 0·125% (v/v) and all other tested organisms, including known multidrug resistant species. Time‐kill assays and metabolic activity tests showed cinnamon oil to exhibit rapid killing, with bactericidal activity observed in ≤6 min at ≥0·5% (v/v). Furthermore, scanning electron microscopy and a membrane permeability assay indicated damage to membrane integrity, loss of turgor and cell collapse. Conclusion Cinnamon bark EO is a broad‐spectrum antimicrobial agent capable of rapid killing at low concentrations. Significance and Impact of the Study This study provides a sound basis for further investigation of the potential of cinnamon bark EO as an alternative to conventional antimicrobial products due to its fast‐acting bactericidal properties at low concentrations.

26A key aspect to routine microbiology processes include the retrieval, transport and 27 maintenance of specimens. Swab transport systems (STS) can be utilised for their low 28 cost, ease of use and their ability to recover and maintain specimens over long 29durations. An increase in healthcare complications due to fungal infections raises the 30 requirement for STS to efficiently recover and preserve pathogens of yeast origin. The 31Clinical and Laboratory Standards Institute (CLSI) M40-A2 protocol is used to assess 32 the compliance of STS to a quality control standard but at present does not include 33 the recovery of yeast. The aim of this study was to compare the results of two 34 commercial STS and their ability to recover and maintain viability of five clinical and 35 reference strains of Candida spp., including C. auris, when stored at room temperature 36 and 4°C, over 48 h, using the qualitative roll plate method. Findings from this study 37 indicate that the STS used in this study are suitable for the collection and maintenance 38of the Candida spp. tested, and is very suitable for the recovery of clinical C. auris. 39 40 41 42 43 44 45 46 47 48

Rising healthcare complications due to fungal infections increase the importance of efficient specimen collection and maintenance systems for correct identification and diagnosis. The CLSI M40-A2 protocol provides guidelines for laboratories assessing quality of medical transport devices, including swab transport systems (STS). This study assessed the efficiency of the Sigma Transwab® foam and flock swab in recovering and maintaining viability of different Candida spp. including C. auris, in different test conditions. Both swab types recovered and maintained viability of all Candida spp. with greater CFU at room temperature after incubation (24 and 48 h) in comparison with swabs maintained at 4 °C.