Blood Cultures

Timing of Blood Collection:

• Preferably during the early stages of fever before initiating antibiotic therapy.
• Multiple collections increase diagnostic accuracy.

Materials:

• 2 blood culture bottles (aerobic/anaerobic), disinfectant, sterile swabs, 20 ml single-use syringe, 2 sterile needles.

Procedure:

1. Warm blood culture bottles to 20-36°C. For suspected endocarditis, meningitis, or pneumonia, maintain the temperature at around 36°C until microbiological processing.
2. Clean the puncture site with disinfectant and a sterile swab. Apply disinfectant again and leave it for at least 30 seconds (preferably 2 minutes).
3. Draw 15-20 ml of blood from a peripheral vein.
4. Use a fresh needle and inject half of the collected blood into each blood culture bottle, holding the bottles with the stopper facing down. Disinfect the rubber stopper before use.
5. Do not ventilate the aerobic blood culture bottle.

Laboratory Request:

• Include information on suspected pathogen, resistance patterns, important clinical data, and prior antibiotic therapy.

Catheter and Drain Tips

Indication:

• Suspected infection from central venous catheter (CVC), arterial catheter, or Redon drain.

Materials:

• Disinfectant, sterile swabs, sterile tube, sterile forceps, sterile scissors.

Procedure:

1. Clean the skin around the catheter insertion site with disinfectant.
2. Remove the possibly infected catheter or drain.
3. Cut the catheter tip (2-3 cm) with sterile scissors and place it into a sterile tube.

Laboratory Request:

• Include relevant information on suspected pathogens and clinical details.

Sputum, Tracheal, and Bronchial Secretions

Note:

• Tracheal and bronchial secretions are usually sterile, and the less contamination from the oral cavity, the higher the specificity of the results.

Collection Techniques:

• Sputum: Have the patient brush their teeth, rinse their mouth with water, and then cough deeply into a sterile container (not just spit). If sputum production is insufficient, inhalation of hypertonic saline (e.g., 10% NaCl) may help.
• Tracheal/Bronchial Secretions: Collect via bronchoscopy (for cytology as BAL) or using a sterile suction catheter in intubated patients or those with a tracheostomy.
• Send the sample in a sterile container; if the sample is small, use a transport medium.

Laboratory Request:

• For suspected tuberculosis (TB), collect sputum on three consecutive days and submit for microscopy, culture, and resistance testing.

Urine

Timing of Urine Collection:

• For optimal bacterial growth, collect urine at least 3 hours after the last void (e.g., morning urine).

Collection Techniques:

• Midstream Urine: Clean the genital area with mild soap solution and dry with a clean towel. Discard the first portion of urine, then collect at least 10 ml in a sterile container.
• Catheter Urine: Clean as described above. Perform catheterization with a single-use catheter and collect at least 10 ml of urine. Do not collect from the catheter bag; instead, disinfect the catheter first.
• Bladder Puncture: Provides the highest diagnostic accuracy since urine is collected without contamination. Follow procedures for suprapubic bladder puncture.

Laboratory Request:

• Refer to specific guidelines for urine culture.

Swabs

Note:

• Swab specimens must be placed in transport medium immediately to prevent desiccation.

Collection Techniques:

• Wound Swab: Collect secretions from the wound bed and its edges.
• Urethral Swab: Collect before the first urination. Do not disinfect! Manually swab the urethra from proximal to distal (in women, from the vagina). If no secretions are present, insert the swab 2 cm into the urethra and rotate it.
• Tonsillar Swab: Press down on the tongue with a spatula. Collect material from inflamed or purulent areas with a swab, avoiding contamination with other mucous areas or saliva.

Laboratory Request:

• Refer to specific guidelines for swab culture.

Punctates

Collection Technique:

• Collect material via puncture (e.g., pleural puncture or ascitic fluid puncture). Inject 5-10 ml of the sample into a blood culture bottle (do not ventilate!) and another 5-10 ml into a sterile container. For TB diagnostics, use only native material without additives.

Laboratory Request:

• For TB: Request microscopy, culture, and resistance testing.

Stool

Note:

• Multiple stool collections increase detection rates. Transport samples quickly to the laboratory.

Collection Techniques:

• Stool Sample: Collect stool from a clean bedpan. Use the spoon of the specimen container to take parts of the stool that are mucous, purulent, or bloody. For liquid stool, collect 3-5 ml.
• Rectal Swab: If stool cannot be obtained, gently insert a swab into the rectum past the anal sphincter, rotate it, and immediately place it in transport medium.

Laboratory Request:

• For pathogens such as Salmonella, Shigella, Yersinia, and Campylobacter. Other targeted requests should be based on clinical suspicion (e.g., recent travel).