Branhamella catarrhalis: phenotypic characteristics.

PURPOSE

This review provides a comprehensive description and discussion of recognized phenotypic characteristics of Branhamella catarrhalis. An emphasis is placed on attributes of this organism that are relevant to its recovery and identification in the clinical microbiology laboratory. In addition, characteristics useful in determining strain identity for use in epidemiologic investigations are addressed. Finally, factors are discussed that may account for the infection-causing potential of B. catarrhalis or at least are of potential consequence to investigations of the pathogenesis of Branhamella disease.

CONCLUSIONS

B. catarrhalis is readily isolated from human clinical specimens and can be easily identified using simple, rapid laboratory techniques. Restriction endonuclease analysis of chromosomal deoxyribonucleic acid has proven to be a useful tool in epidemiologic studies. Beta-lactamase isoelectric focusing is of limited value because of the small number of distinct patterns. The lipopolysaccharide and outer membrane proteins of B. catarrhalis have been characterized and found to be relatively non-varying among different strains. Circumstantial evidence exists in support of the hypothesis that the B. catarrhalis beta-lactamase is a virulence determinant.