The IMViC test remains a critical tool in clinical microbiology for differentiating Enterobacteriaceae – a family housing pathogens like E. coli, Salmonella, and Klebsiella. Despite automation, its cost-effectiveness and reliability make it essential for:
- Identifying urinary tract infection (UTI) pathogens
- Screening stool samples in outbreaks
- Teaching core microbiology principles
Key Concepts to Review
Refresh these before attempting the mock test:
- Test Principles
- Indole: Tryptophan → Indole (Kovac’s reagent = red ring).
- Methyl Red (MR): Glucose → Mixed acids (red if pH ≤4.2).
- Voges-Proskauer (VP): Glucose → Acetoin (Barritt’s reagents = red).
- Citrate: Citrate → Alkaline metabolites (bromothymol blue = blue).
- Classic IMViC PatternsOrganismIndoleMRVPCitrateEscherichia coli++––Klebsiella pneumoniae––++Enterobacter spp.––++Citrobacter spp.–+–+
- Pro-Tips for the Test
- MR results are read at 24 hours; VP requires 48 hours.
- False negatives in Indole test? Check tryptophan levels in the medium.
- Citrate slants must be lightly inoculated to avoid false positives.
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This comprehensive guide equips lab professionals and medical students with:
- 30 high-yield MCQs with detailed explanations (mock test format)
- 50 clinical FAQs covering principles, interpretations & troubleshooting
- Biochemical pattern cheatsheets (E. coli, Klebsiella, Citrobacter)
- Pro strategies for avoiding false results in clinical practice
- Downloadable resources for exam prep and lab reference
Master the Indole, Methyl Red, Voges-Proskauer, and Citrate tests to confidently identify Enterobacteriaceae pathogens in diagnostic settings.
