Complete Genome Sequence and Transcriptomic Analysis of the Novel Pathogen Elizabethkingia anophelis in Response to Oxidative Stress.
Bottom Line: Chrome azurol sulfonate assay verified that siderophore production of E. anophelis is increased in the presence of oxidative stress.We further showed that hemoglobin facilitates the growth, hydrogen peroxide tolerance, cell attachment, and biofilm formation of E. anophelis NUHP1.Our study suggests that siderophore production and heme uptake pathways might play essential roles in stress response and virulence of the emerging pathogen E. anophelis.
Affiliation: School of Biological Sciences, Nanyang Technological University, Singapore.Show MeSH
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Mentions: The blood meal feeding to the A. gambiae drastically reduced the microbial community diversity and favored the growth of Elizabethkingia spp. in its gut (Wang et al. 2011). Thus, we hypothesized that the heme uptake was essential for the growth and oxidative stress response of Elizabethkingia spp. We then compared the impact of ferric iron and the blood-associated iron source, hemoglobin (Hb), on the growth of E. anophelis NUHP1. Surprisingly, addition of ferric iron did not promote the growth of E. anophelis NUHP1 (fig. 5A). This may due to the fact that ferric iron does not have a good solubility in the minimal ABTGC medium we used. Hb enhanced the growth of E. anophelis NUHP1 in a dose-dependent manner (fig. 5B). Moreover, E. anophelis NUHP1 growing in the presence of Hb had a higher level of H2O2 tolerance compared with growth in the presence of ferric iron. The MIC values of H2O2 for E. anophelis NUHP1 grown in minimal medium containing 40 µM Hb or 40 µM FeCl3 were 20 mM and 150 µM, respectively. To test whether it is the utilization or presence of Hb causes enhanced H2O2 resistance, we performed a H2O2 time-kill assay of precultivated E. anophelis NUHP1 cultures with and without the supplementation of 10 µM Hb. We found that supplementation of 10 µM Hb to precultivated E. anophelis NUHP1 cultures enhanced the H2O2 resistance compared with the control cultures (fig. 5C).Fig. 5.—
Affiliation: School of Biological Sciences, Nanyang Technological University, Singapore.