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: Generation of reactive oxygen species is one of the major bactericidal mechanisms from the host innate immune system. Bacterial pathogens have evolved oxidative stress response mechanisms for surviving host colonization (Witko-Sarsat et al. 2000). Elizabethkingia anophelis showed a striking capacity for oxidative stress resistance since hydrogen peroxide (H2O2) is routinely used to clean the hospital sinks where E. anophelis NUHP1 was isolated (Teo et al. 2014). The MIC of H2O2 is 38 mM for E. anophelis NUHP1 cultivated in lysogeny broth (LB) medium under our lab conditions. We exposed exponential growth phase NUHP1 cultures to a sublethal concentration (20 mM) of H2O2 and then used RNA-seq-based transcriptomic analysis to examine potentially important genes for oxidative stress response. RNA-seq analysis indicated that out of the 4,076 predicted E. anophelis genes, 142 displayed statistically significant mRNA level changes of ≥4-fold (adjusted P value < 0.01): 104 of them displaying increased transcript levels (supplementary table S5, Supplementary Material online) and 38 of them displaying decreased transcript levels (supplementary table S6, Supplementary Material online) (fig. 3). Quantitative reverse transcriptase PCR (qRT-PCR) analysis confirmed the expression of 18 highly induced or repressed genes according to RNA-seq analysis. The values obtained by qRT-PCR have a good correspondence with the results of the RNA-seq analysis (table 1).Fig. 3.—
Affiliation: School of Biological Sciences, Nanyang Technological University, Singapore.