Typing of Proteus Strains by Proticine Production and Sensitivity

Abstract

A simple, reliable and highly discriminating scheme for the bacteriocin typing of Proteus was developed. Strains are typed on MacConkey''s agar according to their ability to produce a proticin active against 1 of 14 indicator strains having a single and specific proticin sensitivity and also according to their sensitivity to the different proticin of 13 proticin-producing strains. This new scheme of combined production and sensitivity typing was formulated after 250 strains of Proteus from clinical material were examined for the production of proticins active against the 24 indicator strains of Cradock-Watson''s proticin typing scheme and for proticin activity and sensitivity towards each other. Three new types of proticinogenic strains were discovered and defined. Strains producing proticins of types 1, 2 and 3 were isolated frequently. These common proticins could be subtyped by their different actions on newly characterized indicator strains. By means of this production/sensitivity (P/S) typing scheme, 250 Proteus strains [of P. mirabilis, P. morganii and P. vulgaris] were differentiated into 90 distinct types; typing by sensitivity alone distinguished only 40 types and typing by production alone distinguished only 20 types (including subtypes).