Biology of Haemophilus ducreyi.

Albritton, W L

doi:10.1128/mmbr.53.4.377-389.1989

Cited by 63 publications

(40 citation statements)

References 62 publications

(73 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ability to produce CPE in HFF monolayers was, therefore, apparently independent of the ability of these strains to form microcolonies. The cohesiveness of cells of fresh clinical isolates of H. ducreyi is a well-recognized phenotypic characteristic of this organism (3,22,35) and is likely responsible for the microcolony formation observed in both this and a previous study (4). The potential importance of microcolony formation is reinforced by their presence in lesions formed after intradermal inoculation of rabbits with the virulent 35000 strain (27).…”

Section: Discussionsupporting

confidence: 51%

“…There are several caveats associated with the experiments described above which involved the study of H. ducreyi growth rates and kinetics of adherence to HFF cells in vitro. First, the enumeration of viable organisms (i.e., CFU determinations) to measure the rate of increase in bacterial numbers could be artificially skewed by the tendency of H. ducreyi to autoaggregate (3,22), and strain-to-strain variability in this trait could have affected these numbers. Second, variability in autoaggregation among H. ducreyi strains could have artificially increased the number of bacteria that came into contact with the HFF cells in the attachment assays (i.e., large clumps would settle more quickly and yield a higher degree of attachment).…”

Section: Discussionmentioning

confidence: 99%

“…Chancroid is a sexually transmitted ulcerogenital disease caused by the fastidious gram-negative bacterium Haemophilus ducreyi. In recent years, chancroid has been recognized as an important public health problem in both industrialized and underdeveloped countries (3,22). Of particular concern, chancroid has been implicated as a cofactor in the transmission of the human immunodeficiency virus (7,13,18,26,29,36).…”

mentioning

confidence: 99%

See 2 more Smart Citations

Use of tissue culture and animal models to identify virulence-associated traits of Haemophilus ducreyi

et al. 1995

View full text Add to dashboard Cite

To identify virulence-associated properties of Haemophilus ducreyi, 34 strains of this sexually transmitted pathogen were evaluated for in vitro phenotypic characteristics of potential relevance to chancroid pathogenesis and for their ability to produce lesions in the temperature-dependent animal model for chancroid. Of the 34 strains tested, all but three produced a cytopathic effect on human foreskin fibroblasts (HFF) and all but six strains formed large microcolonies on HFF monolayers. A subset of 12 selected strains underwent more extensive analyses and, when evaluated for both their cytadherence kinetics and growth in the presence of HFF monolayers, it was found that several of these strains had a very limited ability to attach to HFF cells. When the same 12 strains were tested in the temperature-dependent rabbit model, only the seven strains which were positive in all of these in vitro-based tests readily produced lesions. In contrast, the five strains that were noted to be deficient in one or more of the phenotypic characteristics scored in the in vitro systems did not produce lesions. This association between the traits measured in vitro and the ability to produce dermal lesions was significant (P ‫؍‬ 0.0012). These results suggest that in vitro behavior may be used to predict the virulence potential of H. ducreyi strains. Moreover, the phenotypic characteristics described in this study are appropriate focal points for efforts to determine the molecular basis of the virulence of this pathogen.

show abstract

Section: Discussionsupporting

confidence: 51%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Use of tissue culture and animal models to identify virulence-associated traits of Haemophilus ducreyi

et al. 1995

View full text Add to dashboard Cite

show abstract

“…For example, E. coli contains an assortment of adhesins which provide multiple attachment capabilities (14). Alternatively, because H. ducreyi strains in culture possess different colony types (2,22), it is possible that attachment is a function of the amount of each colony type present in the strain. Such differences in attachment capability associated with colony types are found with Neisseria gonorrhoeae, in which two different adhesins, pili and protein II, are subject to phase variation (18).…”

Section: Discussionmentioning

confidence: 99%

Haemophilus ducreyi attaches to and invades human epithelial cells in vitro

et al. 1994

View full text Add to dashboard Cite

Haemophilus ducreyi is a sexually transmitted pathogen that causes genital ulcers and inguinal adenopathy. Because chancroidal ulcers are most commonly located on the foreskins of uncircumcised males, we utilized human foreskin epithelial cells (HFECs) to investigate the initial interaction of H. ducreyi with its host. The eight different strains of H. ducreyi that were studied varied in their abilities to attach to these epithelial cells, with six strains consistently attaching to .90%o of HFECs and two strains attaching to <25% of HFECs. The strains with low levels of adherence also failed to exhibit chaining in broth culture and were avirulent in the rabbit model, suggesting that virulence in this model and attachment may be linked. The most adherent strain, LA228R, was further evaluated for its ability to invade HFECs and HEp-2 cells. Scanning electron microscopy and transmission electron microscopy of HFECs after interaction with LA228R produced images consistent with attachment, ingestion into vesicles, and escape from the vesicles into the cytoplasm. In addition, the gentamicin protection assay and inhibition of invasion by cytochalasin B and D indicated that LA228R was able to invade both HFECs and HEp-2 cells.

show abstract

“…Haemin can serve as a source of both iron and protoporphyrin and is used optionally for growth under anaerobic conditions, whereas NAD, nicotinamide mononucleotide (NMN) or nicotinamide‐riboside are essential (Gingrich and Schlenk, 1944; Leder and Handler, 1951; Shifrine and Biberstein, 1960). Among the relevant Haemophilus species pathogenic to humans, only H. aphrophilus and H. ducreyi are not dependent on NAD (Sadowski and Robertson, 1979; Albritton, 1989; Mutters and Reidl, 1998), and plasmid‐associated NAD independence has been reported for H. parainfluenzae (Windsor et al ., 1991).…”

Section: Introductionmentioning

confidence: 99%

NADP and NAD utilization in Haemophilus influenzae

Reidl

Schlör

Kraiss

et al. 2000

Molecular Microbiology

View full text Add to dashboard Cite

SummaryExogenous NAD utilization or pyridine nucleotide cycle metabolism is used by many bacteria to maintain NAD turnover and to limit energy-dependent de novo NAD synthesis. The genus Haemophilus includes several important pathogenic bacterial species that require NAD as an essential growth factor. The molecular mechanisms of NAD uptake and processing are understood only in part for Haemophilus. In this report, we present data showing that the outer membrane lipoprotein e(P4), encoded by the hel gene, and an exported 5 H -nucleotidase (HI0206), assigned as nadN, are necessary for NAD and NADP utilization. Lipoprotein e(P4) is characterized as an acid phosphatase that uses NADP as substrate. Its phosphatase activity is inhibited by compounds such as adenosine or NMN. The nadN gene product was characterized as an NAD-nucleotidase, responsible for the hydrolysis of NAD. H. influenzae hel and nadN mutants had defined growth deficiencies. For growth, the uptake and processing of the essential cofactors NADP and NAD required e(P4) and 5 H -nucleotidase. In addition, adenosine was identified as a potent growth inhibitor of wild-type H. influenzae strains, when NADP was used as the sole source of nicotinamide-ribosyl.

show abstract

Biology of Haemophilus ducreyi.

Cited by 63 publications

References 62 publications

Use of tissue culture and animal models to identify virulence-associated traits of Haemophilus ducreyi

Use of tissue culture and animal models to identify virulence-associated traits of Haemophilus ducreyi

Haemophilus ducreyi attaches to and invades human epithelial cells in vitro

NADP and NAD utilization in Haemophilus influenzae

Contact Info

Product

Resources

About