Transport Media 50 FAQs and 30 MCQs
Master the essential knowledge of transport media with this comprehensive resource! Perfect for medical lab technicians, microbiologists, and healthcare professionals, this guide covers everything from basic principles to advanced applications.
📌 What’s Included?
✅ 50 Detailed FAQs – Clear answers to critical questions:
- What are the types of transport media (Stuart’s, Amies, Cary-Blair, etc.)?
- How do you select the right medium for bacteria, viruses, or anaerobes?
- What are the storage conditions and shelf life?
- How does transport media differ from culture media?
- Common mistakes and troubleshooting tips.
✅ 30 Challenging MCQs – Test your knowledge with scenario-based questions:
- Which medium is best for stool samples (Cary-Blair vs. buffered glycerol saline)?
- How does Amies medium with charcoal improve bacterial survival?
- What happens if a swab dries out during transport?
- Regulatory guidelines (CLSI, WHO) for specimen transport.
🎯 Who Should Use This?
- MLT/MLS students preparing for certification exams (ASCP, AMT)
- Clinical microbiologists optimizing lab protocols
- Nursing & pharmacy professionals handling sensitive specimens
- Public health workers involved in sample collection & transport
Transport Media 50 FAQs:
1. What is transport media?
Transport media are specialized solutions used to maintain the viability of microorganisms in clinical specimens during transit to the laboratory while preventing overgrowth of contaminants.
2. Why are transport media important?
They ensure specimen integrity, prevent contamination, and maintain pathogen viability for accurate diagnostic testing.
3. How do transport media work?
They provide minimal nutrients (peptones, salts) to sustain microbes without promoting growth, often including inhibitors to suppress contaminants.
4. What is the pH range of most transport media?
Typically 7.2–7.4 (neutral to slightly alkaline) to mimic physiological conditions.
5. Can transport media support microbial growth?
No, they only maintain viability—microbes do not multiply due to limited nutrients.
6. What are the physical states of transport media?
Liquid (e.g., Alkaline Peptone Water), semi-solid (e.g., Stuart’s Medium), and solid (rare).
7. What is Amies Transport Medium used for?
Transporting aerobic/anaerobic bacteria from swabs (e.g., wound, mucosal specimens).
8. When is Cary-Blair Medium preferred?
For enteric pathogens like Salmonella, Shigella, and E. coli in fecal samples.
9. What is Viral Transport Medium (VTM) used for?
Preserving viruses (e.g., SARS-CoV-2, influenza) in nasopharyngeal swabs.
10. Which medium is used for Neisseria gonorrhoeae?
Stuart’s Transport Medium or Amies Charcoal Medium.
11. What is Alkaline Peptone Water used for?
Transporting Vibrio cholerae from fecal samples.
12. Which medium preserves anaerobes?
Anaerobic Transport Medium or Cary-Blair Medium.
13. What is Regan-Lowe Medium for?
Transporting Bordetella pertussis (whooping cough).
14. What is Universal Transport Medium (UTM)?
A versatile medium for bacteria, viruses, and fungi (e.g., Mycoplasma, Ureaplasma).
15. Which medium is used for Chlamydia trachomatis?
Chlamydia Transport Medium or sucrose-phosphate buffer.
16. When should transport media be used?
When delays (>1–2 hours) occur between specimen collection and lab processing.
17. Can transport media be used for fungal specimens?
No—fungi are usually transported dry (e.g., in sterile containers).
18. How do transport media prevent contamination?
By including antimicrobial agents (e.g., antibiotics, antifungals) to inhibit contaminants.
19. Why is buffering important in transport media?
To maintain pH and prevent chemical stress on microbes.
20. Can transport media revive dead organisms?
No—they only preserve viable microbes.
21. How long can specimens survive in transport media?
Typically 24–72 hours, depending on the medium and storage conditions.
22. What happens if transport media are not refrigerated?
Overgrowth of contaminants or pathogen death may occur.
23. Can transport media replace culture media?
No—specimens must be cultured on appropriate growth media for diagnosis.
24. Why are some transport media semi-solid?
To prevent oxidation (e.g., for anaerobes) and reduce leakage.
25. What specimens require immediate processing without transport media?
CSF (cerebrospinal fluid) and blood cultures.
26. What is in Cary-Blair Medium?
Sodium thioglycollate, agar, salts (pH 8.4) for enteric pathogens.
27. What is the role of charcoal in Amies Charcoal Medium?
Neutralizes toxic metabolites for fastidious bacteria (e.g., N. gonorrhoeae).
28. Why is glycerol used in transport media?
As a preservative (e.g., in Buffered Glycerol Saline for fecal samples).
29. What inhibitors are in Viral Transport Medium?
Antibiotics (penicillin/streptomycin) and antifungals (nystatin).
30. What is Leibovitz-Emory Medium for?
Transporting viruses (e.g., herpes simplex).
31. How should transport media be stored before use?
At 2–8°C (unless specified otherwise).
32. Can transport media freeze?
No—freezing kills most microbes (except specific viral media).
33. How much specimen should be added to transport media?
Follow manufacturer instructions (e.g., swabs fully immersed, liquid specimens 1:1 ratio).
34. What is the shelf life of Stuart’s Medium?
9 months if sterilized properly.
35. Can expired transport media be used?
No—reduced efficacy risks false-negative results.
36. Which medium is best for a rectal swab with suspected Shigella?
Cary-Blair Medium.
37. How should a throat swab for Corynebacterium diphtheriae be transported?
In Stuart’s Medium or Amies Medium.
38. What medium preserves Campylobacter in stool?
Cary-Blair Medium (not Buffered Glycerol Saline).
39. Which medium is unsuitable for Vibrio cholerae?
Buffered Glycerol Saline (use Alkaline Peptone Water).
40. How to transport a genital swab for Trichomonas vaginalis?
In Mycoplasma Transport Broth.
41. Why is sodium thioglycollate used in transport media?
To reduce oxygen (supports anaerobes) and act as a reducing agent.
42. What is the role of methylene blue in Stuart’s Medium?
As an oxygen indicator (colorless = anaerobic conditions).
43. Can transport media be homemade?
Yes (e.g., Cary-Blair), but commercial media ensure consistency.
44. Why is fetal calf serum added to viral transport media?
Stabilizes viruses by mimicking host conditions.
45. What is the “holding time” for specimens in transport media?
Ideally ≤48 hours (varies by pathogen).
46. Can transport media be used for environmental samples?
Yes (e.g., water, food testing).
47. What is the difference between “enrichment” and “transport” media?
Enrichment media promote growth; transport media only preserve viability.
48. Can blood samples use transport media?
No—blood requires anticoagulant tubes (e.g., EDTA) or culture bottles.
49. What is the key limitation of transport media?
Cannot replace culturing—only a temporary preservation tool.
50. How has COVID-19 impacted transport media use?
Increased demand for Viral Transport Media (VTM) for RT-PCR testing.
Transport Media 30 MCQs
1. What is the primary purpose of transport media?
A) To promote microbial growth
B) To maintain pathogen viability without multiplication
C) To sterilize clinical specimens
D) To enhance bacterial reproduction
2. Transport media typically have a pH range of:
A) 5.0–6.0
B) 7.2–7.4
C) 8.5–9.0
D) 3.0–4.0
3. Which component is commonly excluded from transport media to prevent microbial growth?
A) Peptones
B) Carbon and nitrogen sources
C) Buffers
D) Sodium chloride
4. Which medium is used for transporting Vibrio cholerae?
A) Stuart’s Transport Medium
B) Alkaline Peptone Water
C) Cary-Blair Medium
D) Viral Transport Medium
5. Amies Transport Medium is suitable for:
A) Viruses only
B) Aerobic and anaerobic bacteria from swabs
C) Fungal cultures
D) Parasitic eggs
6. Which medium contains charcoal to neutralize toxins for Neisseria gonorrhoeae?
A) Cary-Blair Medium
B) Amies Charcoal Transport Medium
C) Buffered Glycerol Saline
D) Regan-Lowe Medium
7. Viral Transport Medium (VTM) typically contains:
A) Antibiotics and antifungals
B) High glucose concentration
C) Blood agar
D) Phenol red indicator
8. Which medium is not suitable for fecal specimens?
A) Cary-Blair Medium
B) Buffered Glycerol Saline
C) Alkaline Peptone Water
D) Stuart’s Medium
9. A rectal swab suspected of Salmonella infection should be transported in:
A) Viral Transport Medium
B) Cary-Blair Medium
C) Anaerobic Transport Medium
D) 5% Formalin
10. Which specimen is not transported in a liquid medium?
A) Nasopharyngeal swab for COVID-19
B) Stool for Shigella
C) CSF (Cerebrospinal Fluid)
D) Urethral swab for Chlamydia
11. For Bordetella pertussis, the recommended transport medium is:
A) Regan-Lowe Medium
B) Stuart’s Medium
C) Alkaline Peptone Water
D) Universal Transport Medium
12. Which medium is used for Mycoplasma species?
A) Mycoplasma Transport Broth
B) Buffered Glycerol Saline
C) Leibovitz-Emory Medium
D) 10% Formalin
13. Transport media should ideally be stored at:
A) –20°C
B) 2–8°C
C) 37°C
D) Room temperature
14. The maximum recommended holding time for most transport media is:
A) 12 hours
B) 24–72 hours
C) 1 week
D) 1 month
15. A key limitation of transport media is:
A) They kill all contaminants
B) They replace the need for culture media
C) They cannot support long-term survival
D) They alter pathogen morphology
16. If a specimen in transport media cannot be processed immediately, it should be:
A) Frozen
B) Refrigerated (unless specified otherwise)
C) Heated to 50°C
D) Exposed to sunlight
17. Sodium thioglycollate in Stuart’s Medium acts as a:
A) Nutrient
B) pH indicator
C) Reducing agent
D) Growth promoter
18. Which component in Cary-Blair Medium maintains osmotic balance?
A) Agar
B) Sodium chloride
C) Calcium chloride
D) Phenol red
19. Why is fetal calf serum added to viral transport media?
A) To inhibit bacteria
B) To stabilize viruses
C) To change pH
D) To enhance fungal growth
20. Which organism is not preserved in Buffered Glycerol Saline?
A) Salmonella spp.
B) Shigella spp.
C) Vibrio cholerae
D) E. coli
21. Transport media can replace culture media for diagnosis.
A) True
B) False
22. Alkaline Peptone Water is acidic in pH.
A) True
B) False
23. Viral Transport Media contain antibiotics to prevent bacterial overgrowth.
A) True
B) False
24. A patient with suspected whooping cough has a nasopharyngeal swab collected. Which medium is optimal?
A) Stuart’s Medium
B) Regan-Lowe Medium
C) Cary-Blair Medium
D) 5% Formalin
25. A stool sample from a cholera outbreak area should be transported in:
A) Alkaline Peptone Water
B) Viral Transport Medium
C) Mycoplasma Transport Broth
D) Universal Transport Medium
26. Which medium is used for Chlamydia trachomatis?
A) Sucrose-phosphate buffer
B) Buffered Glycerol Saline
C) Anaerobic Transport Medium
D) Leibovitz-Emory Medium
27. Universal Transport Medium (UTM) is suitable for:
A) Bacteria only
B) Viruses only
C) Bacteria, viruses, and fungi
D) Parasites only
28. The shelf life of sterilized Stuart’s Transport Medium is:
A) 1 month
B) 6 months
C) 9 months
D) 2 years
29. Which specimen is transported without a medium?
A) Blood for culture
B) Fungal skin scrapings
C) Throat swab for Streptococcus
D) Rectal swab for Salmonella
30. A key advantage of semi-solid transport media is:
A) Faster microbial growth
B) Prevention of leakage and oxidation
C) Higher nutrient content
D) Ability to freeze specimens
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