Wound Swabs basics
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The document discusses guidelines for collecting wound swab specimens. It states that wound swabs are important samples sent to microbiology to identify bacteria and fungi causing infections. However, current practices for collecting and identifying specimens have deficiencies. The document then provides guidance on proper techniques for collecting representative wound swab samples, including cleaning the wound, using sterile swabs, sampling various areas, and promptly transporting swabs to the microbiology lab.
Wound Swabs basics
- 1. Dr.T.V.Rao MD 1
- 2. Why Wound Swabs are Important in Patient Care Wound Swabs are one of the Important Specimens sent to Microbiology Departments for Bacteriological and Fungal isolation and Antimicrobiologial Evaluation. However many basic lacuna in Collection, Laboratory identification and reporting makes the Deficit in Effective care of the Patients and increases the potentials for Morbidity and Mortality Dr.T.V.Rao MD 2
- 3. Events in Infected Wounds Dr.T.V.Rao MD 3
- 4. Obtaining a Specimen Methods of obtaining a specimen from a wound include wound swabbing, needle aspiration and wound tissue biopsy. Although wound swabbing is the most practical and widely used, it is important to use a technique that produces reliable samples for microbiological analysis. Dr.T.V.Rao MD 4
- 5. Wound Culture Protocols Soft skin and tissue infections with open or draining lesions (Appearance of) insect/spider bite with necrotizing centre, drainage & erythema • Abscess - ulcer • Infected laceration ⇒ Culture wound prior to initiation of antibiotics if signs or symptoms of infection are present. If Culture & Sensitivity is obtained after antibiotics have been started, list the drug on the laboratory C& S request. Dr.T.V.Rao MD 5
- 6. What are guideline to Follow for The technique usually employed transferring clinical samples from wounds to microbiology laboratories is the wound swab; however definitive guidelines for this relatively simple procedure have yet to be established. Uncertainty about when swabs should be taken, the correct collection procedure and the appropriate protocols for submitting swabs for investigation have led to a situation where clinicians regularly collect and process unsuitable sample Dr.T.V.Rao MD 6
- 7. Swabs should be collected with Suspected Infection Swabs should therefore be collected only when clinical criteria point to a wound infection and before any antimicrobial interventions have been initiated Dr.T.V.Rao MD 7
- 8. Are there are Standard Protocol in Collection of Specimens It should be noted that the best technique for swabbing wounds has not been identified and validated. The following recommendations can be used as a guide and should be used in conjunction with local protocols: When a swab is indicated, the patient should be given a concise explanation of the need for microbiological investigation and what the procedure involves, for example, that swabs are mainly used to recover species from the surface layers rather than from the deep tissues of a wound. Dr.T.V.Rao MD 8
- 9. Cleaning the contaminating materials is a priority Before a representative sample is collected, any contaminating materials such as slough, necrotic tissue, dried exudate and dressing residue should be removed by cleansing the wound with tap water, sterile saline or debridement Dr.T.V.Rao MD 9
- 10. Appropriate Specimen is Important Do not culture purulent or necrotic debris or drainage over hard eschar. Dr.T.V.Rao MD 10
- 11. Collecting the Optimal Specimen Sterile swabs with cotton or rayon tips are usually used. If the wound is moist a swab can be used straight from the packaging - if the wound is dry, then the swab tip should be moistened with sterile saline to increase the chances of recovering organisms from the site . Swabs with a transport medium that incorporates charcoal enhance the survival of fastidious organisms Dr.T.V.Rao MD 11
- 12. Basic care in Collecting the Specimen Care should be taken to ensure that the swab only comes into contact with the wound surface. Dr.T.V.Rao MD 12
- 13. Care in When Collecting the Swabs 1.Cleanse wound by removing excess debris from wound base with normal saline 2. Thoroughly flush wound with sterile saline. 3. Gently blot excess saline from wound bed with sterile gauze. 4. Remove soiled gloves; apply hand sanitizer. 5. Apply clean gloves Dr.T.V.Rao MD 13
- 14. Practical Approach to Collections of Swabs The swab should be moved across the wound surface in a zigzag motion , at the same time as being rotated between the fingers . Downward pressure to release fluid from the wound surface has been advocated, but this may be painful for the Dr.T.V.Rao MD 14 patient.
- 15. Bigger Wounds Needs Multiple Specimens A representative area of the wound should be sampled. If the wound is large, it may not be feasible to cover the entire surface, but at least 1cm² should be sampled and material from both the wound bed and wound margin should be collected. If pus is present, the clinician should ensure that a sample is sent to the laboratory. Dr.T.V.Rao MD 15
- 16. Devices and Collection of Swabs Dr.T.V.Rao MD 16
- 17. Collecting the Swabs Open sterile culture collection/transport kit containing Amies or Stuarts transport medium and remove swab. If wound is dry, moisten tip of swab with transport fluid at the bottom of the transport sleeve or sterile preservative-free saline (pink saline fish or saline bullet). If wound is moist (weepy) after cleaning, this might not be necessary. Without touching swab to surrounding wound edges or skin, rotate tip of swab over a 1cm area of open wound for 5 seconds (preferred method), or rotate the swab while making a zigzag pattern across the wound at 10 points Dr.T.V.Rao MD 17
- 18. Steps in Collection in Specimen Cleanse intact skin with antiseptic and allow to dry. Expel all air from a 10mL syringe with a 22 gauge needle prior to aspiration. Insert needle into intact skin and apply suction (aspirate). Aspirate approximately 0.5mL of wound fluid. Label syringe (see Swab Culture, above). . After labelling syringe, place in lab biohazard transport bag and transport to the Laboratory Dr.T.V.Rao MD 18
- 19. Transport the Swabs Promptly Immediately following collection, the swab should be returned to its container (placed into the transport medium) and accurately labelled Dr.T.V.Rao MD 19
- 20. Label and Promptly Transport Label culture collection/transport kit with name, birth date, specimen source, date and time of culture. Place in lab biohazard transport container Dr.T.V.Rao MD 20
- 21. Swabs should be Transported without delay Swabs must be transferred to the laboratory as quickly as possible and ideally processed within four hours of collection The laboratory report should list the potential pathogens isolated and the amount of growth observed. The antibiotic susceptibilities of any organisms present in the wound may be included, but whether the isolates are of pathogenic and relevant to the Clinical Details furnished Dr.T.V.Rao MD 21
- 22. Appropriate Culturing Yields Precise Results Apply sufficient pressure to cause tissue fluid to be expressed. It is the bacteria in the tissue fluid that is desired for culture. Dr.T.V.Rao MD 22
- 23. Clinicians should Support with Information Any supporting documentation for the laboratory should immediately be completed and a note included in the patient's records. It is important to provide information to the laboratory staff that will aid their use of the standard operating protocol, such as any underlying co-morbidities, the patient's age, on-going treatment and wound location Dr.T.V.Rao MD 23
- 24. Microbiological and Clinical Correlation is the Best Option Antibiotic susceptibilities of any organisms present in the wound may be included, but whether the isolates are of clinical significance or whether antibiotic therapy is required is a matter of clinical judgement. Spreading cellulitis and clinical infections will require systemic antibiotics. Dr.T.V.Rao MD 24
- 25. Limitation of Swab Techniques To examine the diagnostic validity of swab techniques, analyses of the accuracy as compared to tissue cultures in identifying microbial load provide insight into the utility of swab techniques used for this purpose. The accuracy of swab specimens based on Levine's technique was significantly higher than those based on Z-technique and approached significance when compared to swabs based on wound exudates Dr.T.V.Rao MD 25
- 26. Programme Created By Dr.T.V.Rao MD for Medical and Paramedical Professionals in the Developing World Email doctortvrao@gmail.com Dr.T.V.Rao MD 26