The typing of Morganella morgani by bacteriocin production and sensitivity

Abstract

Summary.A typing scheme for Morganella morgani based on bacteriocin (morganocin) production and sensitivity is described. These characteristics were determined by testing 160 strains in all combinations and permitted their differentiation into 90 types. Morganocin production was induced with mitomycin C and morganocin sensitivity determined with a diluted inoculum on Lab-lemco agar at 30°C. Most strains (82.5%) produced morganocins and 49 different types were defined. Most strains (97.5%) were sensitive to morganocins and usually to several different types. The scheme is more discriminating than other reported methods. The finding in an epidemiological survey of the carriage of certain strains in the bowel for several weeks suggests that in practice the method is stable and reproducible.

Discovery of new morganocin types of Morganella morganii in strains of diverse serotype and the apparent independence of bacteriocin type from serotype of strains

“…The 21 strains of M. morgunii used for morganocin production and sensitivity typing were most of the standard typing strains previously described (Senior, 1987). (Strains Mg 122 and Mg 130 have died.)…”

“…These were the UV-irradiated and chloroformed supernates of mitomycin C-induced cultures of the strains growing exponentially at 30°C in PP3 medium in the dark. They were prepared as previously described (Senior, 1987).…”

“…The plates were incubated overnight at 30°C and then examined under good illumination for zones of i&ibited \ growth of the indicator strains. The type of morganocin produced, denoted by a number, was determined from a knowledge of the range of indicator strains inhibited and by reference to Senior (1987) which defined each morganocin type.…”

“…The morganocin preparations used were those of strains Mg 1 (type 32), Mg 63 (type 47), Mg 39 (type 44), Mg 100 (type 38), Mg 77 (type 19), Mg 8 (type 43) and Mg 126 (type 40). The morganocin sensitivity of a strain, denoted by a letter, was determined from a knowledge of the range of the above seven morganocins to which it was sensitive and by reference to Senior (1987) which defined morganocin sensitivity types.…”

“…In studying the pathogenic and virulence properties of M. morganii, it is helpful to have a method for fine strain recognition within the species. Therefore, we investigated the usefulness of the bacteriocin typing method of Senior (1987) as a reliable and discriminating method when applied to a variety of serologically distinct strains of M. morganii from several European countries.…”