Transport media for Haemophilus ducreyi

Area of Science:

• Microbiology
• Clinical Diagnostics
• Infectious Diseases

Background:

• Haemophilus ducreyi is the causative agent of chancroid, a sexually transmitted infection.
• Accurate laboratory diagnosis of H. ducreyi requires timely and appropriate sample transport to maintain bacterial viability.
• Existing transport media may not adequately preserve H. ducreyi viability, potentially impacting diagnostic accuracy.

Purpose of the Study:

• To evaluate the efficacy of various transport media for maintaining Haemophilus ducreyi viability.
• To compare the performance of newly formulated media against established transport media.
• To determine optimal storage conditions and timeframes for H. ducreyi transport from clinical specimens.

Main Methods:

• Simulated laboratory study evaluating Stuart's, Amies', and four novel thioglycollate/hemin-based transport media (SA, SGA, SG, GA).
• Assessment of H. ducreyi viability after storage at room temperature and 4°C for varying durations.
• Clinical evaluation using swabs from chancroid patients, direct plating, and storage in optimal transport media at 4°C.

Main Results:

• No tested medium maintained H. ducreyi viability beyond 24 hours at room temperature.
• Amies' medium supported viability for up to 3 days at 4°C.
• Newly formulated media (SGA and GA) maintained H. ducreyi viability for over 4 days at 4°C, with 90% recovery after 1 week in GA.
• Direct plating from genital ulcerations yielded a 71% recovery rate of H. ducreyi.

Conclusions:

• Refrigerated storage at 4°C significantly enhances H. ducreyi viability in transport media compared to room temperature.
• Thioglycollate/hemin-based media containing selenium dioxide, L-glutamine, and albumin (SGA) or L-glutamine and albumin (GA) are superior for H. ducreyi transport.
• These optimized transport media improve the potential for laboratory confirmation of chancroid, even after extended storage periods.