Eswab: Types and Uses

Eswab is a multipurpose transport system for collecting and transporting samples in the microbiology laboratory. It consists of the flocked swab and 1ml of liquid amies packed in the plastic screw cap tube. Eswab is suitable for transporting aerobic, anaerobic, and fastidious bacteria. 

Eswab supports the viability of the bacteria for up to 48 hours either in the room or at refrigerator temperature (Neisseria gonorrhoeae survive up to 24 hours). The E in the eswab stands for the elute. The eswabs by companies like Copan are sterilized using gamma irradiation during manufacture. So, it can be used directly in the aseptic condition during sampling.  It is a kind of electromagnetic radiation with higher energy that can destroy bacterial and viral DNA. 

Types of Eswab

These swabs are suitable for collecting samples in different locations. Based on the swab format, there are different types of eswab.

Multiple Swabs

It consists of a double or triple swab. One swab is the nylon-flocked swab having a breakpoint at 80 mm. The others are rayon or flocked swabs without the breakpoint. 1 ml of the liquid amies medium is present in it. 

Single Regular 

It consists of the nylon flocked swab having an 80 mm breakpoint and 1 ml of the liquid amies medium. 

Single Mini Tip 

A single mini tip is a nylon-flocked swab with a breakpoint at 80 mm or 100 mm. A mini-tip swab is used to collect the small site or the pediatric sample. 

How to collect the sample by eswab?

1. Put on personal protective equipment like gloves and a mask before sample collection.
2. Open the peel pouch, remove the tube and label it properly.
3. Then unscrew the cap and remove it. 
4. Collect the sample from the patient and insert it into the bottom of the tube.
5. Don’t touch the swab applicator below the breakpoint. Break the swab shaft at 180° at the marked breakpoint by holding the tube away from the face. 
6. Then screw the cap on the tube tightly to avoid leakage, label it properly and transport it to the laboratory as soon as possible.   
7. Once the sample is collected, it should be transported to the laboratory and processed as soon as possible. But if in case of delay, it should be stored in the refrigerator at 4-8°C or room temperature between 20-25°C. As per the CLSI guideline, cultures of Neisseria gonorrheae should be processed within 24 hours of their collection. 

Advantages of the Flocked Swab over the Fiber Swab

• A flocked swab is made of nylon fiber, which helps to collect the samples better than that traditional swabs. The flocked swab sample stays on the surface of the swab, and when it gets in contact with the medium, it gets eluted completely.
• The flocked swab has no internal core, so the sample gets collected close to the surface. In the traditional fiber swabs, the sample is trapped in the swab fibers, and only one sample is used for the single test. 
• In the traditional fiber swab, only 10 percent of the sample is available, whereas, in the flocked swab, about 90 percent of the sample is available. From the single tube, ten aliquots of a sample can be prepared.

Uses of Eswab

1. Eswab is used for anaerobic culture, fungal culture, Staphylococcus aureus and MRSA (Methicillin-resistant Staphylococcus aureus) culture, VRE (Vancomycin-resistant Enterococcus) culture, and eye, ear, throat, wound culture and stain. However, tissue or fluid is preferred over the swab for the anaerobes, wound, and fungus culture.
2. Eswab is used for Gram staining, automation, rapid antigen testing, and molecular assays. Since from one sample, multiple tests can be done; only a few samples will also be sufficient to perform the multiple tests. It reduces the cost associated with the different collection devices. 

References:

1. Vermeiren, C., Marchand-Senécal, X., Sheldrake, E., Bulir, D., Smieja, M., Chong, S., Forbes, J. D., & Katz, K. (2020). Comparison of Copan ESwab and FLOQSwab for COVID-19 Diagnosis: Working around a Supply Shortage. Journal of clinical microbiology, 58(6), e00669-20. https://doi.org/10.1128/JCM.00669-20
2. Gandhi, B., Summerbell, R., & Mazzulli, T. (2018). Evaluation of the Copan ESwab Transport System for Viability of Pathogenic Fungi by Use of a Modification of Clinical and Laboratory Standards Institute Document M40-A2. Journal of clinical microbiology, 56(2), e01481-17. https://doi.org/10.1128/JCM.01481-17
3. Silbert, S., Kubasek, C., Uy, D., & Widen, R. (2014). Comparison of ESwab with traditional swabs for detection of methicillin-resistant Staphylococcus aureus using two different walk-away commercial real-time PCR methods. Journal of Clinical Microbiology, 52(7), 2641–2643. https://doi.org/10.1128/JCM.00315-14
4. Fontana, C., Favaro, M., Limongi, D., Pivonkova, J., & Favalli, C. (2009). Comparison of the eSwab collection and transportation system to an amies gel transystem for Gram stain of clinical specimens. BMC Research Notes, 2, 1–6. https://doi.org/10.1186/1756-0500-2-244
5. https://mediadelivery.copangroup.com/wp-content/uploads/2021/06/Brochure_FLOQSwabs.pdf
6. https://www.copanusa.com/wp-content/uploads/2019/07/LBM-ESwab-051519.pdf
7. https://www.copanusa.com/wp-content/uploads/2019/07/LBM-Brochure-041219-web.pdf