Proteus-typing by proticin production and susceptibility

Area of Science:

• Microbiology
• Bacteriology
• Clinical Diagnostics

Background:

• The established Proteus typing method relies on proticin production and susceptibility.
• Modifications were needed to enhance the sensitivity and discriminatory power of existing Proteus typing techniques.

Purpose of the Study:

• To refine a Proteus-typing method by optimizing proticin preparation and standardization.
• To evaluate the enhanced method's ability to differentiate clinical Proteus isolates based on proticin activity and susceptibility.

Main Methods:

• Modified a Proteus typing method using fluid-prepared proticins applied to agar plates before inoculation.
• Utilized a defined set of 10 proticin producer strains and 28 indicator strains for susceptibility pattern determination.
• Standardized proticin production temperature and assessed proticin similarity through titrations.

Main Results:

• Developed an enhanced Proteus S-P typing system yielding 86 distinct S-P types from 148 clinical isolates across four species.
• Identified 39 new S-P types in a separate validation set of 100 clinical Proteus isolates.
• Demonstrated consistent typing results from repeated isolations from the same patients.

Conclusions:

• The enhanced Proteus S-P typing method is effective for differentiating Proteus vulgaris and Proteus mirabilis.
• The method shows limitations in typing Proteus rettgeri and Proteus morganii due to insufficient discriminatory power.