Evaluation of a Proteus rettgeri O-serotyping system for epidemiological investigation.

An evaluation of the serotyping system for Proteus rettgeri has been performed through its application to 561 human isolates of this species. Of these, 545 were typable and could be separated into 58 O serotypes. A group of isolates from one hospital, and clinically implicated in cross-infections, was found to belong the same O serotype, confirming the clinical findings. Isolates with more than one specificity of thermostable antigen, in most cases, were found to have combinations of such specificities restricted to combinations previously defined for the O-type strains. Furthermore, the use of pooled antisera was investigated and system of pooling was devised to retain the specificity of the system and to increase the facility of the typing procedure.