Differences in genetic diversity of nonecapsulated Haemophilus influenzae from various diseases

Abstract

Genetic relationships among 80 isolates of nonencapsulated Haemophilus influenzae recovered from different disease types were determined by multilocus enzyme electrophoresis (MEE) a t 13 enzyme loci in an attempt to assess the association between multilocus genotype and disease. The isolates were obtained from 15 patients with meningitis, 10 with otitis media, I 9 with chronic bronchitis, 20 with cystic fibrosis, and 16 were obtained from healthy carriers. The 80 isolates were assigned to 69 electrophoretic types (ETs) falling into 5 groups. Isolates from each disease entity were represented by a variety of genotypes; however, cluster analysis from a matrix of genetic distances between ETs revealed that the ETs of the otitis media and meningitis isolates were all clustered within a genetic distance of 055 (group I). In addition, no genotypes were shared between H. influenzae carrier isolates and isolates from cases of disease. H. influenzae isolates from healthy individuals were distributed significantly differently from those from chronic bronchitis meningitis and otitis media patients. The genetic diversity (H) of carrier strains was greatest, although not statistically different from that of isolates from patients with disease. It was concluded that the genetic distribution of acute disease isolates is not random over the five ET groups, although the genetic diversity within the groups is not different. The effect of bacterial persistence in the host on the genetic diversity of H. influenzae is discussed.

Secondary Structure and Molecular Analysis of Interstrain Variability in the P5 Outer-Membrane Protein of Non-Typable Haemophilus Influenzae Isolated from Diverse Anatomical Sites

“…As it is suggested that NTHi isolates from acute infections are more diverse than either carrier or chronic respiratory infection isolates [5], it was of interest to determine if the heterogeneity in P5 from various anatomical sites represented the same diversity. The hypervariable regions in this analysis occur predominantly in three regions, which correspond to the first three surfaceexposed loops, similar to the hypervariable regions identified by Duim et al [6].…”

“…This includes chaperones and outer-membrane ushers that form anchor proteins which connect the fimbriae to the cell [31]. The genomic organisation of the p. 5 gene does not suggest that same organisation seen with other fimbrial operons, at least in the Rd strain [20]. However, the possibility that P5 plays some role in the biogenesis of fimbriae cannot be excluded and may help explain some of the anomalies associated with the lack of fimbriae in the P5 mutant strain [7].…”

“…Chromosome fingerprint analysis of NTHi isolates from patients with COPD demonstrated genetic diversity [4]. However, analysis of genetic types by multi-locus enzyme electrophoresis suggested that isolates from persistent carriage or chronic infections are more diverse than isolates from acute infections [5]. The major outer-membrane protein (OMP) profile of chronic bronchitic isolates varies in the electrophoretic mobility of proteins P2 (protein b, c) and P5 (protein d) [4].…”

Comparison of usefulness of randomly amplified polymorphic DNA and amplified-fragment length polymorphism techniques in epidemiological studies on nasopharyngeal carriage of non-typable Haemophilus influenzae

“…outermembrane protein typing, MLEE, PFGE, RAPD or multilocus sequence typing, have been used to evaluate NTHI strain relationships (Fuste et al, 1996;Gazagne et al, 1998;Gilsdorf, 1998;Moor et al, 1999;Saito et al, 1999;St Geme et al, 1994;van Belkum et al, 1994van Belkum et al, , 1997. Of these, some were aimed at finding differences among NTHI strains isolated from patients with persistent infections and from healthy humans (Cerquetti et al, 2000;van Alphen et al, 1991van Alphen et al, , 1997.…”

“…Compared with encapsulated strains, non-encapsulated H. influenzae are less well characterized and are thought to be more diverse (Fuste et al, 1996). Most studies directed towards recognizing links between closely related but not identical NTHI strains have been conducted by application (Fuste et al, 1996;Jordens et al, 1993;van Alphen et al, 1997).…”