22/05/2025
1. Purpose:
To identify urinary tract infection (UTI) pathogens.
To determine effective antibiotics against isolated organisms.
2. Sample Collection:
Type: Midstream clean-catch urine.
Container: Sterile urine container.
Instructions:
• - Clean urethral area with antiseptic.
• - Discard first stream; collect midstream.
• - Avoid touching the container rim.
3. Media Used:
CLED Agar
MacConkey Agar
Blood Agar (if needed)
4. Inoculation Procedure:
Use calibrated loop (1 µL or 10 µL).
Streak semi-quantitatively on media.
Incubate at 35–37°C for 18–24 hours.
5. Interpretation of Growth:
Colony Count (CFU/mL)
10⁵ = Significant bacteriuria (UTI Likely)
Pure growth with significant count suggests infection.
Mixed growth may indicate contamination.
6. Identification of Pathogens:
Based on colony morphology, Gram stain, and biochemical tests (Indole, Citrate, TSI, Urease, etc.).
Use of automated systems (VITEK, MALDI-TOF) when available.
7. Sensitivity Testing:
Method: Kirby-Bauer disk diffusion.
Medium: Mueller-Hinton agar.
Procedure:
• - Adjust turbidity to 0.5 McFarland standard.
• - Inoculate evenly; apply antibiotic discs.
• - Incubate at 35–37°C for 16–18 hours.
• - Measure zones of inhibition.
8. Common Pathogens:
*Escherichia coli (Gram-negative)
*Klebsiella pneumoniae (Gram-negative)
*Proteus mirabilis (Gram-negative)
*Enterococcus faecalis (Gram-positive)
*Staphylococcus saprophyticus (Gram-positive)
9. Sample Report Format: [Example]
Patient Name: [Insert Name]
Specimen: Midstream Urine
Date Received: [Insert Date]
Culture Findings: Escherichia coli (>10⁵ CFU/mL)
Antibiotic Sensitivity Results:
Interpretation of Growth:
Colony Count (CFU/mL) Interpretation
10⁵ Significant bacteriuria
Common Pathogens:
*Escherichia coli (Gram-negative)
