Pus (wound, Abscesses, Burns and sinuses) culture & sensitivity

1. Pus (wound, Abscesses, Burns and sinuses) culture & sensitivity

2. Aim of the test • Isolate and identify aerobic and anaerobic pathogenic organisms pus specimen. • Types of specimen: • Swabs from the infected area or aspiration from deep wounds. Swabs in anaerobic transport media for the isolation of anaerobes.

3. Criteria of specimen rejection • Inappropriate specimen transport device; mislabeled specimen; unlabelled specimen. • dried samples and specimen received after prolonged delay (usually more than 72 hours). • specimen received in expired transport media

4. Pathogen and commensals

5. Specimen collection • Pus from abscess is best to collected at the time, the abscess is incised and drained. • Using sterile technique, aspirate or collect from drainage tube up to 5 ml of pus, transfer to sterile container. • If pus is not being discharged use sterile cotton wool swab to sample from the infected site. • extend the swab deeply into the depth of the lesion. • Immerse the swab in container of transport medium • label it and send to the laboratory as soon as possible

6. Quantity of specimen • Sufficient amount on swab, or aspiration in transport media or syring • Time relapse before processing the sample:30 min. • Storage • Maintain specimen swab at room temperature. Do not refrigerate.

7. Specimen processing • Media • ‰ Blood Agar, • ‰ Chocolate Agar, • ‰ MacConkey Agar • ‰ Thioglycollate broth

12. Culturing procedure • Streak one blood agar plates, one chocolate, MacConkey and inoculate thioglycollate broth tube. • Gram stain to check the presence or absence and if present the type or types and the predominant organisms.

14. Post specimen processing • Interfering factors: • Patient on antibiotic therapy. • Improper sample collection. • Result reporting: • Report Gram stain finding as an initial report. • Report the isolated pathogen/s and its sensitivity pattern as a final report.

15. Turn around time: • Gram stain results should be available 1 hour after specimen receipt. • Isolation of a possible pathogen can be expected after 2-3 days. • Negative culture will be reported out 1-2 days after the receipt of the specimen.

16. Additional information • Contamination of the specimen with normal flora is one of the major obstacles in obtaining good results. • Care should be taken to avoid contaminating the specimen with normal flora. • This could e accomplished by swabbing superficial infected wounds with 70% alcohol.