LIPOPOLYSACCHARIDES AS DETERMINANTS OF SEROLOGICAL VARIABILITY IN PSEUDOMONAS-CORRUGATA

The variation in biochemical and serological features of 128 isolates of Pseudomonas corrugata has been studied with 56 isolates from Spain and 72 isolates from other countries. Isolates were analyzed with comm on diagnostic tests and with the API50CHE system. Variability among is olates for some standard tests usually listed as positive or negative for this species, such as arginine dihydrolase and gelatin hydrolysis, lipase and lecithinase activities, pigment production, and wrinkled c olony morphology, was observed. Three antisera were raised against the type strain and two Spanish isolates from tomato and pepper plants. S erological reactions were studied by indirect immunofluorescence and i ndirect enzyme-linked immunosorbent assay. Eighty-three isolates react ed with a single antiserum, 6 reacted with two antisera, and none reac ted with three antisera. Thirty-nine isolates did not react with any o f the three antisera. These results suggest that serology will not be a useful method for routine diagnosis of P. corrugata unless common an tigens can be identified. Electrophoresis and immunoelectrotransfer we re used to study the antigens involved. Each antiserum reacted with wh ole-cell lysates, giving two common hands for P. corrugata isolates an d other Pseudomonas species and a ladder-like pattern characteristic o f lipopolysaccharides (LPS). Common bands were not observed after prot einase K treatment. More than 10 LPS patterns were distinguished in 98 isolates after silver staining of polyacrylamide gels. There was no c orrelation between the geographical origin or host of the isolates and the LPS patterns. A correlation between LPS groups and serological re action was observed.