Cloning of the haemocin locus of Haemophilus influenzae type b and assessment of the role of haemocin in virulence

Murley, Yvette M.; Edlind, Thomas D.; Plett, P Artur; LiPuma, John J.

doi:10.1099/00221287-144-9-2531

Cited by 14 publications

(14 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although in vitro experiments suggest that exchange of encapsulation loci is possible, the clonal population structure of these bacteria suggests that this is uncommon. Additionally, we found that hmcA (19), the structural gene encoding the type b-specific bacteriocin haemocin was absent in all non-type b encapsulated isolates, suggesting that none of these strains was related to Hib (data not shown).…”

Section: Vol 71 2003 Non-type B Encapsulated H Influenzae Virulencmentioning

confidence: 86%

Prevalence and Distribution of Adhesins in Invasive Non-Type b Encapsulated Haemophilus influenzae

et al. 2003

View full text Add to dashboard Cite

show abstract

Section: Vol 71 2003 Non-type B Encapsulated H Influenzae Virulencmentioning

confidence: 86%

Prevalence and Distribution of Adhesins in Invasive Non-Type b Encapsulated Haemophilus influenzae

et al. 2003

View full text Add to dashboard Cite

show abstract

“…The Rd genome is estimated to be 270 kb smaller than that of virulent type b strain Eagan (6). Capsule type b (24), pili (hif) (44), tryptophanase (tna) (27), and haemocin (hmc) (30) genes are present in Hib strains and are not found in Rd. The cap b, hif, and tna loci are each flanked by direct repeats.…”

mentioning

confidence: 99%

Identification and Genetic Characterization of Haemophilus influenzae Genetic Island 1

Chang¹,

Gilsdorf

DiRita

et al. 2000

Infect Immun

View full text Add to dashboard Cite

“…E9 is similar to the H. influenzae type b strain E1a hemocin gene (hmcD) and has a GϩC content that is much lower than the 38% reported for H. influenzae strain Rd KW20 (10) (hereafter referred to as Rd). Interestingly, the entire hmc E1a locus has a significantly lower GϩC content (20), suggesting that it represents a genomic region acquired by H. influenzae encapsulated and nonencapsulated strains from an unrelated source. A small portion of F2 is similar to srmB of Rd (10), which is related to D-E-A-D box helicases (26), while most of it is related to a Neisseria meningitidis MC58 adhesin (32) and the Moraxella catarrhalis UspA2 and UspA2H proteins.…”

mentioning

confidence: 99%

Genomic Analysis of the F3031 Brazilian Purpuric Fever Clone of Haemophilus influenzae Biogroup Aegyptius by PCR-Based Subtractive Hybridization

et al. 2002

View full text Add to dashboard Cite

PCR-based subtractive genome hybridization produced clones harboring inserts present in Brazilian purpuric fever (BPF) prototype strain F3031 but absent in noninvasive Haemophilus influenzae biogroup aegyptius isolate F1947. Some of these inserts have no matches in the GenBank database, while others are similar to genes encoding either known or hypothetical proteins. One insert represents a 2.3-kb locus with similarity to a Thermotoga maritima hypothetical protein, while another is part of a 7.6-kb locus that contains predicted genes encoding hypothetical, phage-related, and carotovoricin Er-like proteins. The presence of DNA related to these loci is variable among BPF isolates and nontypeable H. influenzae strains, while neither of them was detected in strains of types a to f. The data indicate that BPF-causing strain F3031 harbors unique chromosomal regions, most of which appear to be acquired from unrelated microbial sources.Haemophilus influenzae biogroup aegyptius was identified in the mid 1980s as the etiological agent of Brazilian purpuric fever (BPF), a frequently fatal invasive pediatric disease (6). Originally, a clone was isolated from patients with BPF in Sao Paulo State, Brazil (7). However, after outbreaks in other regions of Brazil (12, 34) and in Australia (19, 37) and a case of a child from Connecticut with an infection consistent with BPF (35), it is clear that a single H. influenzae biogroup aegyptius strain or clone is not the sole agent responsible for BPF. These observations led to the hypothesis that BPF-causing strains harbor DNA that is absent in noninvasive isolates, which may encode the factors that transformed a benign microorganism into an aggressive pathogen. This hypothesis was tested by using a genomewide approach based on PCR-based subtractive genome hybridization.Generation of a subtracted genomic library. We first addressed an important concern: both strains contain a 24-MDa plasmid (7). The significance of this is that differences in plasmid content between the F3031 and F1947 strains could result in misleading subtractive hybridization results. Restriction and Southern blot analyses (25) showed that the plasmids from F3031 and F1947 have similar AccI restriction profiles and cross hybridize, although they have some differences in their RsaI patterns (Fig. 1A and B). Nevertheless, the plasmid contents of these two strains are similar and should not affect the subtractive hybridization process.A library enriched in DNA unique to F3031 was made with the Clontech PCR-Select bacterial genome subtractive kit by using F3031 and F1947 total DNAs. After confirming that such a library was obtained, a secondary PCR with nested primers was conducted and the amplicons were cloned with a TA system (Invitrogen) and Escherichia coli DH5␣ or TOP10FЈ (Table 1) competent cells. Colony hybridization (25) with 32 Plabeled, RsaI-digested F1947 and F3031 genomic DNA showed that approximately 27% of the clones contained DNA unique to F3031, a value comparable to that described by the kit manufacture...

show abstract

Cloning of the haemocin locus of Haemophilus influenzae type b and assessment of the role of haemocin in virulence

Cited by 14 publications

References 46 publications

Prevalence and Distribution of Adhesins in Invasive Non-Type b Encapsulated Haemophilus influenzae

Prevalence and Distribution of Adhesins in Invasive Non-Type b Encapsulated Haemophilus influenzae

Identification and Genetic Characterization of Haemophilus influenzae Genetic Island 1

Genomic Analysis of the F3031 Brazilian Purpuric Fever Clone of Haemophilus influenzae Biogroup Aegyptius by PCR-Based Subtractive Hybridization

Contact Info

Product

Resources

About