}]]}]}]}] 30:T28b8,

### Specimen Collection Principles - Accurate diagnosis of mycotic infections relies on appropriate specimen collection. - Fungal and mycobacterial infections often present similarly, so specimens are frequently cultured for both. ### Respiratory Tract Specimens - **Samples:** Sputum, Induced Sputum, Bronchial Washings (BW), Bronchoalveolar Lavage (BAL), Tracheal Aspirate. - **Collection:** - Most common for fungal culture. - Patients should collect sputum from a deep cough in the morning. - **Note:** A nebulizer may be needed if the patient cannot produce sputum. - All sputum specimens must be collected in a sterile, screw-cap container. - **Transport:** Quickly; avoid delays. - **Processing:** - May be stored at room temperature if processed within 2 hours. - If delayed, refrigerate at 4°C. - Antimicrobial agents are used to prevent bacterial overgrowth. - **Note:** Upper respiratory tract has normal flora; use **0.5mL cycloheximide** (antifungal agent) in the medium. - If viscous, digest with **N-acetyl-L-cysteine** and concentrate. Use both nonselective and selective media with antimicrobials. Prepare **KOH mount**. ### Nasal Sinus Specimens (Surgical) - **Collection:** Collected surgically by ENT. - **Transport:** Immediately. - **Processing:** Plate directly onto media containing antimicrobials, **except cycloheximide** (inhibits some pathogenic molds). ### Vaginal Specimens - **Collection:** Use a sterile swab or fluid in a sterile container. - **Transport:** Within 24 hours of collection using culture transport swabs. - **Processing:** - Screen for yeasts and incubate at 30°C for 7 days. - Culture only when clinically indicated; direct smear microscopy is helpful. - **Note:** Always check the fungal form (yeast or mold) and temperature requirements (room temp or 35-37°C). ### Urine Specimens - **Collection:** - 24-hour urine samples are unacceptable. - A first voided morning urine specimen is preferred. - **Transport:** Promptly; may refrigerate briefly if delay is unavoidable. - **Processing:** - Process as soon as possible. - Centrifuge all urine samples; use the sediment (pellet) for culture. - **Note:** If a urine transport system is used, samples can be stored at room temperature for up to 72 hours. ### Cerebrospinal Fluid (CSF) - **Collection:** By physician, in a sterile screw-cap tube. Aseptically collect 25 mL for concentration. - **Transport:** Immediately at room temperature; **do not refrigerate**. - **Processing:** - Concentrated by centrifugation before inoculation (especially if sample <1mL). - **Note:** Fungi are heavier, so use the pellet, not the supernatant. - If >5mL, filter through a membrane filter (0.45µm pore size). Place filter portions on media. - Use 1 drop for **India ink** or **latex agglutination** (for *Cryptococcus*). - **Note:** CSF is sterile; **no antibiotics needed**. **Never refrigerate CSF specimens.** ### Blood Specimens - **Collection:** No special considerations. Collect 20-30 mL for adults; divide into 2 bottles. Maintain proper blood-to-broth ratio (1:5 to 1:10). - **Transport:** Room temperature; process immediately. - **Processing:** - **Lysis Centrifugation System:** Used for dimorphic fungi (e.g., *Histoplasma capsulatum*). - Most detected within 4 days; *H. capsulatum* recovery: 10-14 days. - **Automated Blood Culture System:** Provides accurate etiology determination. - **Isolator tube:** Most sensitive method for fungal recovery. - Optimal tempera