Identification of Haemophilus ducreyi

Sturm, A. W.

doi:10.1007/bf00399078

Cited by 3 publications

(3 citation statements)

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“…However, these reports used the standard approach in virulence studies for human pathogens, i.e., incubation temperatures of 35±378C. Because the optimal growth temperature for H. ducreyi is 338C [9,13,14], as The adhesion kinetics of reference strain A77 were low, and were similar at 338Cand 378C. The ®nding of low adhesion kinetics of this strain at 378C is in keeping with those reported by other investigators [7,18].…”

Section: Discussionsupporting

confidence: 66%

“…Reference strains A77 and CIP542 served as avirulent and virulent controls, respectively (A. W. Sturm, unpublished data). The strains were cultivated on Modi®ed Bieling (MB) plates containing IsovitaleX 1% or yeast dialysate 2% [13]. The plates were incubated at 338C in microaerobic conditions for 48 h. The purity of H. ducreyi was con®rmed by colonial morphology and Gram's stain.…”

Section: Bacterial Strains and Inoculum Preparationmentioning

confidence: 99%

“…H. ducreyi interaction with host cells in vivo is mainly with the skin, an organ of lower temperature (c. 338C). This is also the optimal incubation temperature for the H. ducreyi in vitro [13,14]. Therefore, temperature may play a role in the expression of virulence determinants of H. ducreyi.…”

Section: Introductionmentioning

confidence: 99%

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The effect of temperature on the interaction of Haemophilus ducreyi with human epithelial cells

Makakole

Sturm

2001

Journal of Medical Microbiology

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To investigate if temperature affects the interaction of Haemophilus ducreyi with human epithelial cells, nine strains were used to evaluate the adhesion kinetics of the organism at 338C and 378C. The effect of the free toxin on the epithelial cells at those temperatures was also assessed. The cyto-adherence kinetics of H. ducreyi to the epithelial cells was signi®cantly greater at 338C (10 times more) than at 378C in all seven clinical isolates tested. There was a signi®cant difference in cell-associated H. ducreyi at 338C as compared with 378C. Control strains showed similar adhesion properties at both temperatures. However, the virulent strain CIP542 adhered in larger amounts than the avirulent strain A77. Electron microscopy revealed that there was more tissue necrosis at the lower than the higher temperature. The effect of the free toxin was the same at each temperature. However, strain A77 had signi®cantly lower toxicity than strain CIP542 and the clinical isolates. These results suggest that H. ducreyi displays a temperature-dependent interaction with human epithelial cells, and this feature may play a role in the virulence of the organism in vivo. While the overall toxic effect of viable bacteria depends on the metabolic activity of the bacteria and is, therefore, higher at 338C than at 378C with the same initial inoculum, the effect of the extracted toxin at molecular level with ®xed concentrations is a temperatureindependent event.

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Section: Discussionsupporting

confidence: 66%

Section: Bacterial Strains and Inoculum Preparationmentioning

confidence: 99%