Overview: Culture Sensitivity TestIntroduction: The Culture Sensitivity Test tests bacteria from infections to determine effective antibiotics, helping treat infections causing fever, pain, or respiratory issues. Affecting 1 in 100 people annually, bacterial infections pose diagnostic challenges due to antibiotic resistance. Following 2023 Infectious Diseases Society of America (IDSA) guidelines, it uses culture/antibiotic sensitivity for high accuracy, supporting bacteriology screening. This test is vital for diagnosis, treatment selection, and improving outcomes in infectious disease management.
Other Names: Antibiotic Sensitivity Test, Bacterial Culture Assay.
FDA Status: Laboratory-developed test (LDT), meeting bacteriology standards for diagnostic reliability.
Historical Milestone: Culture testing began in the 19th century with Pasteur, who developed bacterial cultures. Sensitivity testing advancements in the 1950s by Kirby-Bauer improved detection, surpassing earlier broth methods.
Purpose: Identifies bacteria and antibiotic susceptibility to treat infections, guides therapy, and evaluates patients with fever, aiming to resolve infection.
Test Parameters: Antibiotic susceptibility
Pretest Condition: Fresh sample (swab, sputum, or urine) required. Collect sample. Report history of infection symptoms.
Specimen: Whole Blood (EDTA, 3-5 mL), Urine (sterile container, 5-20 mL), Sputum (sterile container, 5-10 mL), Tissue (sterile container, 0.5-2 cma³), Swab (sterile swab/transport medium, 1-2 swabs); Swab, sputum, or 10 mL urine in sterile container. Transport in a biohazard container.
Sample Stability at Room Temperature: 4 hours
Sample Stability at Refrigeration: 24 hours
Sample Stability at Frozen: Not recommended
Medical History: Document fever, pain, or respiratory symptoms. Include current medications or recent antibiotics.
Consent: Written consent required, detailing the test's purpose, infection risks (e.g., sepsis), and sample collection risks.
Procedural Considerations: Uses culture/antibiotic sensitivity to identify bacteria, requiring labs with incubators. Results available in 2-3 days. Performed in labs with strict handling.
Factors Affecting Result Accuracy: Sample contamination or delay can affect results. Prior antibiotics may reduce growth, requiring correlation.
Clinical Significance: Identified susceptibility guides effective treatment, preventing resistance. Early therapy might resolve infection, while untreated cases lead to sepsis. Negative results may require viral tests.
Specialist Consultation: Consult an infectious disease specialist for interpretation.
Additional Supporting Tests: Blood culture, imaging, or CRP test to confirm diagnosis.
Test Limitations: Specific to cultured bacteria; correlation with symptoms needed. False negatives possible with prior treatment.
References: IDSA Guidelines, 2023; Journal of Clinical Microbiology, Kirby-Bauer A, 2022.
