Rates in vitro changes of gonococcal colony opacity phenotypes

Area of Science:

• Microbiology
• Bacteriology
• Genetics

Background:

• Neisseria gonorrhoeae exhibits colony opacity phenotypes, which are important for its virulence and survival.
• Understanding the dynamics of phenotype switching is crucial for comprehending gonococcal adaptation and pathogenesis.

Purpose of the Study:

• To quantify the rate of colony opacity phenotype switching in Neisseria gonorrhoeae.
• To investigate factors influencing the transition rate between opaque and transparent phenotypes.

Main Methods:

• Determination of the rate of change of colony opacity phenotype across 12 Neisseria gonorrhoeae strains.
• Assessment of transition rates between opaque and transparent states.
• Evaluation of the effect of piliation state, passage history, growth conditions (temperature, pH, oxygen), media additives, and DNA on transition rates.

Main Results:

• The average rate of colony opacity phenotype change was approximately 2 X 10(-3) per colony-forming unit per generation, ranging from 0.2 X 10(-3) to 4 X 10(-3).
• Opaque-to-transparent and transparent-to-opaque transitions occurred at similar rates.
• Piliation state, passage history, altered growth conditions, media additives, and DNA presence did not affect the transition rate.

Conclusions:

• Neisseria gonorrhoeae exhibits a high and consistent rate of colony opacity phenotype switching.
• The transition rate is robust and not significantly influenced by a wide range of tested environmental and genetic factors.
• The implications of this high transition rate for gonococcal adaptation and infection are significant.