Mar 09, 2022

Public workspaceEnvironmental sampling using Moore swabs

This protocol is a draft, published without a DOI.
  • 1Wellcome Trust Research Laboratory, Christian Medical College, Vellore, India;
  • 2UK Health Security Agency;
  • 3Malawi Liverpool Wellcome Trust, Blantyre, Malawi;
  • 4Imperial College London;
  • 5University of Washington
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Protocol Citation: Dilip Abraham, Nicola Elviss, Nicholas Feasey, Nick Grassly, Jacob John, Gagandeep Kang, John Scott Meschke, Venkata Raghava Mohan, Satheesh Nair, Jonathan Rigby, Rajan Srinivasan, Catherine Troman, Christopher Uzzell, Nicolette Zhou 2022. Environmental sampling using Moore swabs. protocols.io https://protocols.io/view/environmental-sampling-using-moore-swabs-bresm3ee
Manuscript citation:
Liu P, Ibaraki M, Kapoor R, Amin N, Das A, Miah R, Mukhopadhyay A, Rahman M, Dutta S, Moe C (2021), Development of Moore Swab and Ultrafiltration Concentration and Detection Methods for Salmonella Typhi and Salmonella Paratyphi A in Wastewater and Application in Kolkata, India and Dhaka, Bangladesh. Frontiers in Microbiology, doi: 10.3389/fmicb.2021.684094
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License,  which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it’s working
Created: January 13, 2021
Last Modified: April 10, 2024
Protocol Integer ID: 46258
Keywords: Salmonella, Typhi, Paratyphi, wastewater, environmental surveillance
Disclaimer
Please note, the author list is in alphabetical order and does not reflect contribution.
Abstract
A protocol for the collection of environmental samples (sewage and wastewater) using Moore swabs and subsequent laboratory processing up to DNA extraction. This is part of a set of protocols for environmental surveillance of Salmonella Typhi.

Bacteria in the wastewater are trapped in the Moore swab. Trapped bacteria are enriched during incubation in Universal Pre-Enrichment broth. The broth is then filtered under a vacuum to capture the bacteria on filter discs ready for DNA extraction.

This protocol is adapted from the Moore swab protocol described in Liu et al (2021).
Guidelines
It is recommended that sample collection be done in the morning.
Materials
ReagentUniversal Pre-Enrichment BrothFischer ScientificCatalog #DF0235-17-8

Moore swabs
Wide-mouth jars (500ml capacity)
Cold packs and ice box
20ml pipet
Membrane filtration apparatus
45mm 0.45um filter discs
Empty Powerbead tubes or equivalent (2ml screw cap microcentrifuge tubes)

Appropriate PPE (Disposable lab coats, nitrile gloves, face mask) and disinfectant
Before start
Ensure that you wear appropriate PPE during sampling (e.g. gloves, disposable lab coat, appropriate footwear, facemask).
Sample Collection
Sample Collection
Sterilise Moore swabs by autoclaving prior to taking them to the field site.
Immerse the swab in the sewage or wastewater channel and tie it to a stable support using the tailing thread of the swab.
Leave in place for 24-72 hours
Prepare 450ml of Universal Pre-Enrichment broth per sample, following the manufacturer's instructions
Cut the thread of the Moore swab and transfer the swab to an appropriately labelled container with 450ml of UPE broth
Place the container on ice and transport back to the lab within 4 hours of sample collection
Processing the Moore Swab
Processing the Moore Swab
Incubate the container with the Moore swab in UPE broth at Temperature37 °C for 21 - 24 hours

After incubation, swirl the mixture and pipet two 20ml aliquots from the enrichment broth into 50ml conical flasks


Assemble the membrane filtration unit according the manufacturer's instructions and attach to the vacuum pump
Using sterile tweezers, place a 47mm 0.45µm filter disc onto the filtration unit head and attach the filtration unit cup
Pipet the first 20ml sample into the filtration cup and turn on the vacuum to filter the sample through the disc
Once complete, cut the filter into several strips using sterile forceps then place the strips into an empty PowerBead tube. If possible, place the strips so that the "dirty" side faces the inside of the tube.
Repeat steps 10 to 12 with the second 20ml sample.
Store samples at Temperature-20 °C until extraction.

Thoroughly disinfect filtration cups, containers and conical flasks after use to avoid cross contamination of samples.