Ausmedia Alkaline Peptone Water (APW) is a specialised selective enrichment broth primarily used in microbiology to isolate Vibrio species, such as Vibrio cholerae and Vibrio parahaemolyticus, from clinical specimens, food, and environmental water samples.
Core Principle
The medium operates on two key physiological advantages of Vibrio bacteria:
Alkaline Tolerance: Most intestinal bacteria (like E. coli) are inhibited by high pH levels. APW is typically adjusted to a pH of 8.4 to 8.6, which favours the rapid growth of Vibrio while suppressing competing flora.
Halophilic Growth: Many species, particularly marine vibrios, require or are stimulated by salt. Standard APW contains 1% Sodium Chloride, but variants for marine samples may increase this to 2–3% (often called Alkaline Saline Peptone Water).
Key Applications
Cholera Screening: It is the "gold standard" for enriching Vibrio cholerae from faecal samples or rectal swabs.
Food Safety: Used to detect pathogenic vibrios in seafood (e.g., shrimp, oysters, and fish).
Transport Medium: It serves as an excellent transport medium for suspected cholera cases, maintaining bacterial viability for up to 24 hours.
Microscopy: Facilitates direct microscopic examination (hanging drop method) to observe the characteristic "darting motility" of Vibrio.
Customer Reviews