Analysis of Genetic Relatedness of Haemophilus influenzae Isolates by Multilocus Sequence Typing

• DOI: 10.1128/jb.01207-07
• Publication Date: 2007-12-08T01:53:35Z
• Authors: Alice L. Erwin; Sara A. Sandstedt; Paul J. Bonthuis; Jennifer L. Geelhood; Kevin L. Nelson; William C. T. Unrath; Mathew A. Diggle; Mary J. Theodore; Cynthia R. Pleatman; Elizabeth A. Moth...; Claudio T. Sacchi; Leonard W. Mayer; Janet R. Gilsdorf; Arnold L. Smith
• Keywords: Multilocus sequence typing

ABSTRACT The gram-negative bacterium Haemophilus influenzae is a human-restricted commensal of the nasopharynx that can also be associated with disease. majority H. respiratory isolates lack genes for capsule production and are nontypeable (NTHI). Whereas encapsulated strains known to belong serotype-specific phylogenetic groups, structure NTHI population has not been previously described. A total 656 strains, including 322 have typed by multilocus sequence typing found 359 types (ST). We performed maximum-parsimony analysis sequences calculated majority-rule consensus 4,545 resulting equally most parsimonious trees. Eleven clades were identified, consisting six or more ST on branch was present in 100% Two additional defined branches 91% 82% trees, respectively. Of these 13 clades, 8 consisted predominantly three serotype specific, 2 contained distinct NTHI-specific clusters strains. Sixty percent within one eBURST identified an group 20% There concordant clustering certain metabolic reactions putative virulence loci but disease source geographic origin. conclude well-defined groups exist differ genetic content. These observations will provide framework further study effect diversity interaction host.