Implementation of a Colorectal Surgical Site Infection Prevention Bundle and Checklist: A Quality Improvement Project.

After noting an elevated surgical site infection rate in 2019 associated with colorectal surgeries, leaders at two Central Virginia health system hospitals convened an interdisciplinary team to audit current practices and research infection prevention strategies. After identifying a lack of standardization in care processes for colorectal surgery patients and reviewing the literature on colorectal bundles, the team created a bundle focusing on the use of antibiotics, chlorhexidine gluconate wipes or baths, separate closing instrument trays, nasal decolonization, bowel preparation, and maintaining patient normothermia. After synthesis and stakeholder input, the team implemented the colorectal bundle along with a checklist for all users to complete to ensure compliance and standardization of practice and for auditing purposes. Implementation results were positive: the total number of colorectal infections decreased from nine in 2020 to three in 2021. Education was critical to securing staff member engagement for successful implementation of and compliance with the bundle.

Consideration of the probative value of single donor 15-plex STR profiles in UK populations and its presentation in UK courts.

The adoption of new 15 locus STR multiplex systems into UK forensic science would be facilitated by agreed guidelines for reporting the strength of DNA evidence using likelihood ratios. To facilitate such an agreement, we present an analysis of previously published UK allele frequencies for white Caucasian, Afro-Caribbean and Indo-Pakistani populations and investigate their effect on likelihood ratios for single donor profiles. We consider the implication of the five additional loci and suggest a procedure for reporting likelihood ratios for 15-plex STR profiles.

A survey of paint flakes on the clothing of persons suspected of involvement in crime.

A survey was undertaken to determine the background level of paint flakes on the clothing of persons suspected of involvement in crime. The debris from 100 garments submitted for casework examination was studied and paint flakes recovered where present. Seventy two percent of garments bore one or more flakes. A total of 703 flakes were recovered; size, topcoat colour, and number and colour of any under-layers were recorded for each. The distribution of paint flakes on clothing surfaces and in pockets was also noted. Results were compared with the previously published survey of Pearson, May and Dabbs (1971). This survey provides scientists with an updated data set for reference when considering the strength of paint evidence.

Forensic validation of the PowerPlex® ESI 16 STR Multiplex and comparison of performance with AmpFlSTR® SGM Plus®.

We describe the forensic validation of Promega's PowerPlex® European Standard Investigator 16 (ESI 16) multiplex kit and compare results generated with the AmpFlSTR® SGM Plus® (SGM+) multiplex. ESI 16 combines the loci contained within the SGM+ multiplex with five additional loci: D2S441, D10S1248, D22S1045, D1S1656, and D12S391. A relative reduction in amplicon size of the SGM+ loci facilitates an increased robustness and amplification success of these amplicons with degraded DNA samples. Tests performed herein supplement ESI 16 data published previously with sensitivity, profile quality, mock casework, inhibitor and mixture study data collected in our laboratories in alignment with our internal technical and quality guidelines and those issued by the Scientific Working Group on DNA Analysis Methods (SWGDAM), the DNA Advisory Board (DAB) and the DNA working group (DNAWG) of the European Network of Forensic Science Institutes (ENFSI). Full profiles were routinely generated from a fully heterozygous single source DNA template using 62.5 pg for ESI 16 and 500 pg for SGM+. This increase in sensitivity has a consequent effect on mixture analyses and the detection of minor mixture components. The improved PCR chemistry confers enhanced tolerance to high levels of laboratory prepared inhibitors compared with SGM+ results. In summary, our results demonstrate that the ESI 16 multiplex kit is more robust and sensitive compared with SGM+ and will be a suitable replacement system for the analysis of forensic DNA samples providing compliance with the European standard set of STR loci.

Developmental validation of the PowerPlex® ESX 16 and PowerPlex® ESX 17 Systems.

We describe the developmental validation study performed on the PowerPlex(®) ESX 16 (European Standard Extended 16) and the PowerPlex(®) ESX 17 Systems, part of a suite of four new DNA profiling kits developed by Promega in response to the ENFSI and EDNAP groups' call for new STR multiplexes for Europe. The PowerPlex(®) ESX 16 System combines the 11 loci compatible with the UK National DNA Database, contained within the AmpFlSTR(®) SGM Plus(®) PCR Amplification Kit, with five additional loci: D2S441, D10S1248, D22S1045, D1S1656 and D12S391. The multiplex was designed to incorporate these five new loci as mini- and midi-STRs while maintaining the loci found in the AmpFlSTR(®) SGM Plus(®) kit as standard size. The PowerPlex(®) ESX 17 System amplifies the same loci as the PowerPlex(®) ESX 16 System, but with the addition of a primer pair for the SE33 locus. Tests were designed to address the developmental validation guidelines issued by the Scientific Working Group on DNA Analysis Methods (SWGDAM), and those of the DNA Advisory Board (DAB). Samples processed include DNA mixtures, PCR reactions spiked with inhibitors, a sensitivity series, and 306 United Kingdom donor samples to determine concordance with data generated with the AmpFlSTR(®) SGM Plus(®) kit. Allele frequencies from 242 white Caucasian samples collected in the United Kingdom are also presented. The PowerPlex(®) ESX 16 and ESX 17 Systems are robust and sensitive tools, suitable for the analysis of forensic DNA samples. Full profiles were routinely observed with 62.5 pg of a fully heterozygous single source DNA template. In mixture analysis, a range of 52-95% of unique minor contributor alleles was observed at 19:1 mixture ratios where only 25 pg of the minor component was present. Improved sensitivity combined with the robustness afforded by smaller amplicons has substantially improved the quantity of information obtained from degraded samples, and the improved chemistry confers exceptional tolerance to high levels of laboratory prepared inhibitors.

Analysis and interpretation of mixed profiles generated by 34 cycle SGM Plus(®) amplification.

Interpretation rules for standard 28 cycle PCR have been described previously for the analysis of mixed STR profiles. In this study the same guidelines are applied to 200 mixtures derived from pairs of known donors combined in ratios of 1:1, 2:1 and 5:1 which have been profiled in duplicate with SGM Plus(®) at total inputs ranging from 1ng to 50pg. The paired profiles were distributed among 35 FSS (Forensic Science Service) reporting officers trained in low copy number (LCN) interpretation who analysed them blind following standard casework procedures. Based upon the results from initial duplicate 34 cycle PCR reactions, the reporting officers made appropriate decisions regarding the benefits of processing the reserved third aliquot. Using the combined results, 49 consensus profiles were successfully resolved into major and minor contributor peaks. This demonstrates the reliability of the interpretation rules used in standard 28 cycle SGM Plus analysis when applied to 34 cycle generated profiles by trained and experienced reporting officers. No minor contributor peaks were assigned to a major profile in the final reported results. Those profiles which did not show sufficiently marked and consistent differentiation into major and minor peaks would have been correctly resolved if the profile of one contributor (e.g. the "victim") was known.

Developmental validation of the PowerPlex(®) ESI 16 and PowerPlex(®) ESI 17 Systems: STR multiplexes for the new European standard.

In response to the ENFSI and EDNAP groups' call for new STR multiplexes for Europe, Promega(®) developed a suite of four new DNA profiling kits. This paper describes the developmental validation study performed on the PowerPlex(®) ESI 16 (European Standard Investigator 16) and the PowerPlex(®) ESI 17 Systems. The PowerPlex(®) ESI 16 System combines the 11 loci compatible with the UK National DNA Database(®), contained within the AmpFlSTR(®) SGM Plus(®) PCR Amplification Kit, with five additional loci: D2S441, D10S1248, D22S1045, D1S1656 and D12S391. The multiplex was designed to reduce the amplicon size of the loci found in the AmpFlSTR(®) SGM Plus(®) kit. This design facilitates increased robustness and amplification success for the loci used in the national DNA databases created in many countries, when analyzing degraded DNA samples. The PowerPlex(®) ESI 17 System amplifies the same loci as the PowerPlex(®) ESI 16 System, but with the addition of a primer pair for the SE33 locus. Tests were designed to address the developmental validation guidelines issued by the Scientific Working Group on DNA Analysis Methods (SWGDAM), and those of the DNA Advisory Board (DAB). Samples processed include DNA mixtures, PCR reactions spiked with inhibitors, a sensitivity series, and 306 United Kingdom donor samples to determine concordance with data generated with the AmpFlSTR(®) SGM Plus(®) kit. Allele frequencies from 242 white Caucasian samples collected in the United Kingdom are also presented. The PowerPlex(®) ESI 16 and ESI 17 Systems are robust and sensitive tools, suitable for the analysis of forensic DNA samples. Full profiles were routinely observed with 62.5pg of a fully heterozygous single source DNA template. This high level of sensitivity was found to impact on mixture analyses, where 54-86% of unique minor contributor alleles were routinely observed in a 1:19 mixture ratio. Improved sensitivity combined with the robustness afforded by smaller amplicons has substantially improved the quantity of data obtained from degraded samples, and the improved chemistry confers exceptional tolerance to high levels of laboratory prepared inhibitors.