Effect of temperature on growth of the pathogenic oomycete Pythium insidiosum

Area of Science:

• Medical Mycology
• Infectious Diseases
• Diagnostic Microbiology

Background:

• Pythium insidiosum causes pythiosis, a severe infection requiring prompt diagnosis for effective treatment.
• Early and accurate diagnosis of pythiosis is critical for improving patient prognosis.
• Previous isolation attempts of P. insidiosum have been hindered by suboptimal specimen handling, particularly temperature exposure.

Purpose of the Study:

• To investigate the effect of different temperatures on the growth and viability of Pythium insidiosum.
• To determine optimal culture conditions for the successful laboratory isolation of P. insidiosum.
• To provide guidance for improving diagnostic accuracy in cases of suspected pythiosis.

Main Methods:

• Cultures of Pythium insidiosum were incubated at various temperatures, including low (8°C), high (42°C), and optimal ranges (28°C and 32°C).
• Growth and viability of the organism were monitored under these different temperature conditions.
• The success rate of P. insidiosum isolation was evaluated based on incubation temperature.

Main Results:

• Incubation at low (8°C) and high (42°C) temperatures resulted in either the death or significant inhibition of Pythium insidiosum growth.
• Optimal growth and successful isolation of Pythium insidiosum were achieved when cultures were maintained at temperatures of 28°C and 32°C.
• Temperature is a critical factor influencing the successful laboratory culture of P. insidiosum.

Conclusions:

• Maintaining appropriate temperatures during sample processing and culture is essential for the successful isolation of Pythium insidiosum.
• Diagnostic laboratories should utilize optimal temperatures (28-32°C) for culturing specimens to diagnose pythiosis effectively.
• Understanding temperature-dependent growth is key to improving diagnostic yields for Pythium insidiosum infections.