Pus Sample Collection & Processing (1).pptx

Pus sample collection

1. Pus Sample Collection & Processing Dr. Aditya Rana(MBBS,MD) SR, Microbiology DRPGMC, Tanda

2. Introduction Pus is a whitish-yellow or yellow substance produced during inflammatory responses of the body that can be found in regions of pyogenic bacterial infections . An accumulation of pus in an enclosed tissue space is known as an abscess . A visible collection of pus within or beneath the epidermis , is known as a pustule. Pus is produced from the dead and living white blood cells which travel into the intercellular spaces around the affected cells .

3. Types of Pus Sample Abscess Ulcers Discharge

4. Sample Collection What Should be the ideal time of sample collection ?

5. Collection of pus from Abscess For closed wounds(abscess) Disinfect this skin with chlorhexidine(%?) or alcohol (%?) followed by an iodine solution. (%?) Remove Iodine with Alcohol prior to specimen collection. Question : So what should be Contact time ?

6. Sample Collection

7. Samples collected by using a syringe and needle should be placed in a sterile container or blood collection tube without anticoagulant for submission to the laboratory. A portion of the sample should also be placed in a sterile tube containing anaerobic medium like (?) if an anaerobic culture is required.

8. Open Wounds

9. Collection of sample from Open wounds Cleanse the superficial area thoroughly with sterile saline, changing sponges with each application. Remove all superficial exudates. Remove overlying debris with scalpel and swabs or sponges. Collect sample from base or advancing margin of lesion.

10. Sample collection from Swabs Cotton swabs Calcium alginate swabs Dacron swabs Rayon swabs Other swabs

11. Cotton Swabs Fatty acids in cotton swabs are toxic to Neisseria gonorrhoeae and Bordetella pertussis therefore, cotton swabs should never be used for culturing Bordetella or gonococci. Cotton swabs can used to collect specimens, including specimens for PCR tests . Still, they are not recommended as residues present in cotton-tipped swabs inhibit PCR assays. A cotton swab moistened with phosphate-buffered saline is used to collect specimens from the base of the ulcer.

12. Calcium alginate swabs Swabs made of calcium alginate are commonly used to collect nasopharyngeal specimens (excluding those specimens for chlamydia or viral culture). Calcium alginate fibers are toxic for tissue culture, inactivate certain viruses, such as HSV, and interfere with PCR and fluorescent-antibody tests. Calcium alginate swabs are generally more toxic for gonococci and mycoplasmas than treated cotton swabs. Cotton and calcium alginate swabs are not recommended for microbiological diagnostics

13. Dacron Swabs Dacron and rayon swabs contain non-toxic, hydrophilic synthetic fibers. Dacron swabs are the least toxic and most efficient at releasing antigens. Dacron swabs are also preferred swabs for molecular assays and viral specimens. Dacron-tipped swabs on plastic shafts are acceptable for collecting most upper respiratory tract microorganisms, chlamydiae, and even genital Mycoplasmas

14. Rayon swabs Sterile rayon swabs with plastic shafts are suitable for collecting most upper respiratory tract microorganisms. Rayon-tipped swabs on a thin wire may also be used to collect specimens for isolation of mycoplasmas and chlamydiae.

15. Swab Designs The lack of sufficient specimen volume is the major limitation of swab usage. To overcome this limitation, newer swab designs are used. Swab tip structure may be flocked fiber, tightly wound, or knitted. Newer swab designs, such as flocked swabs or sponges, are made to capture more specimens and, later, better release the sample into a transport medium or onto an agar plate.

16. Traditional fiber swab specimens have an internal mattress core that can trap organisms and may be vortexed (mixed) in 0.5 to 1 mL of saline or broth for 10 to 20 seconds to dislodge material from fibers.

17. A flocked swab has been designed to uptake a large volume of liquid sample. Flocked swabs contain no mattress core, sample stays close to the surface and elutes out rapidly and spontaneously. Flocked swabs have short nylon fiber strands attached perpendicularly to the plastic applicator. Capillary hydraulics between the strands draws samples from the sampling site into this hydrophilic layer.

18. Elution occurs when the swab is placed in the liquid medium supplied with the swab. This improved design enhances the recovery of both aerobes and anaerobes.

19. Shafts used in swabs Swab shafts are made up of aluminum or plastic, or wooden shafts. Swabs with plastic shafts are recommended for collecting bacteria, viruses, and mycoplasmas from mucosal membranes. The organisms are more easily removed from the plastic shafts than from other materials such as wooden shafts or wire.

20. Shafts used in swabs Swabs with cotton tips and wooden shafts are not recommended for virology and molecular tests. Wooden shafts are toxic to many bacteria, such as Chlamydia trachomatis and viruses. Calcium alginate swabs with aluminum shafts are also used to amplify nucleic acids

21. Standard precautions to be followed while handling the specimen Note: Syringes with the needle attached should not be accepted due to the sharps and biohazard risk to staff. Grossly contaminated specimen or leaky containers and collection containers of doubtful sterility must be noted and mentioned. Deliver aspirates and tissues to the laboratory within 30 minutes for best recovery.

22. Do not refrigerate or incubate before or during transport. If there is a delay, keep sample at room temperature, because at lower temperature there is likely to be more dissolved oxygen, which could be detrimental to anaerobes.

23. Rejection Criteria For anaerobic culture, avoid swab collection if aspirates or biopsy samples can be obtained. Do not accept specimens for microbiological analysis in container with formalin.

24. Processing Sample swabs always taken in pair(2 swabs) For Microscopy, Direct gram staining,Other stainings OR KOH preparation For Culture

25. Describe the appearance of the specimen Colour of the pus Look for the Granules if any

26. Culture Cultures are always streak on Blood Agar MacConkey Agar Further identification is done by biochemical reactions

27. Reading of culture plates One or two different colonies are processed. Three of more than three colonies are taken as contamination (exception Immunocompromised state, Diabetic ulcers & Burn patients) Rarely polymicrobial infection. Skin commensals are not reported.

28. THANKS