Lipopolysaccharide and high-molecular-weight polysaccharide serotypes of Pseudomonas aeruginosa

The serotype distribution of bacteremic and nonbacteremic clinical isolates of Pseudomonas aeruginosa in relation to the Fisher immunotyping scheme, the International Antigenic Typing System (IATS), and high-molecular-weight polysaccharide determinants was investigated. Of 281 bacteremic isolates, 273 (97.2%) were serotyped by one of the seven IATS specificities that correspond to a Fisher lipopolysaccharide/high-molecular-weight polysaccharide specificity. In contrast, these seven serotypes accounted for only 68.5% of the 124 nonbacteremic clinical isolates. Review of the reported serotype distribution of P. aeruginosa isolates in Europe further supported the finding of a limited serotype distribution among bacteremic clinical isolates. Fifteen of the 17 IATS serotypes were found among all of the strains of P. aeruginosa serotyped, an indication that most of the IATS serotypes are present in the United States. Thus, only certain lipopolysaccharide immunotypes of P. aeruginosa occur as clinical bacteremic isolates, and a multivalent, high-molecular-weight polysaccharide vaccine directed at the lipopolysaccharide type determinants of P. aeruginosa has potential usefulness.