New O antigens of Morganella morganii and the relationships between haemolysin production. O antigens and morganocin types of strains.

A collection of 142 strains of Morganella morganii, principally from unrelated patients' faeces was examined to determine the relationship, if any, between haemolysin production, O antigen and morganocin production/sensitivity type. Only 55 (38.7%) were agglutinable with the existing 44 O antisera. However, when O antisera were raised to some of the non-typable strains 11 new O antigens were found and 126 (88.7%) of the strains were typable. The number of O antigenic groups in M. morganii is now 55. It was confirmed that the O antigenic characteristics of strains were independent from morganocin producer types. An epidemiological retrospective survey showed that finer strain recognition in M. morganii can be achieved by using both methods than either method alone. Approximately 30% of strains were haemolytic. The ability to produce haemolysin was more common in strains of certain O serogroups and morganocin producer types than in others.