Clonal diversity in Haemophilus pleuropneumoniae

Abstract

Genetic diversity among 135 isolates of nine serotypes of Haemophilus pleuropneumoniae recovered from pigs with pleuropneumonia or other invasive diseases in 14 countries was estimated by multilocus enzyme electrophoresis, which detects allelic variation in structural genes. Thirty-two multilocus genotypes (electrophoretic types [ETs]) were distinguished on the basis of allele profiles at 15 enzyme loci, and 36 distinctive combinations of ET and serotype were identified. The recovery of isolates with identical properties in widely separated geographic regions and over a 20-year period indicated that the population structure of H. pleuropneumoniae is clonal. Isolates of the same ET generally shared the same serotype and electrophoretic pattern of the outer membrane proteins, but some ETs were represented by isolates of several different serotypes, outer membrane protein patterns, or both. On average, the genetic diversity among ETs of the same serotype was 56% of the total genetic diversity in the species. Isolates of serotype 1, which are unusually pathogenic, belong to a distinctive group of clones that are closely related to clones marked by serotype 9.

Clonal analysis of the Actinobacillus pleuropneumoniae population in a geographically restricted area by multilocus enzyme electrophoresis

“…In agreement with previous findings (10, 17,21) this study revealed that the species A. pleuropneumoniae has a clonal structure. Of 250 isolates analyzed, 66% belonged to three ETs (ET-10, ET-15, and ET-17) of a total of 37 ETs identified in the study.…”

“…As seen in Table 2, the genetic diversity (H) of the serotypes differed significantly among the 187 Danish isolates. As the calculated genetic diversity will depend, in part, on the selection of isolates, enzymes, and running conditions chosen for MEE, it is difficult to form any conclusions about the H values in our work compared with those reported by Musser et al (17). However, in general, the genetic variance of the total number of isolates is smaller in our work (0.247 compared with 0.428).…”

Molecular characterization of a protective outer membrane lipoprotein (OmlA) from Actinobacillus pleuropneumoniae serotype 1

“…Thus, intramuscular injection of a bacterin prepared from one serotype protects from homologous but not heterologous challenge (14). This antigenic variability among A. pleuropneumoniae serotypes has been confirmed by comparison of the outer membrane profiles and by multilocus enzyme electrophoresis indicating a clonal origin of isolates belonging to the same serotype (21).…”

Actinobacillus pleuropneumoniaeserotype 7 siderophore receptorFhuAis not required for virulence

“…In fact, the serotype 7 FhuA protein showed a higher level of homology to FhuA of E. coli than to that of A. pleuropneumoniae serotype 1. Such discrepancies be- tween proteins belonging to strains from di¡erent serotypes support the clonal population structure of A. pleuropneumoniae [23]. To date, two other serotype-speci¢c outer membrane proteins of A. pleuropneumoniae have been identi¢ed, the outer membrane lipoprotein OmlA [24] and the transferrin-binding protein TbpB [14].…”