Lrp, a global regulator, regulates the virulence of Vibrio vulnificus.

BACKGROUND: An attenuated mutant (designated NY303) of Vibrio vulnificus, which causes serious wound infection and septicemia in humans, was isolated fortuitously from a clinical strain YJ016. This mutant was defective in cytotoxicity, migration on soft agar and virulence in the mouse. The purpose of this study was to map the mutation in this attenuated mutant and further explore how the gene thus identified is involved in virulence. METHODS: The whole genome sequence of mutant NY303 determined by next-generation sequencing was compared with that of strain YJ016 to map the mutations. By isolating and characterizing the specific gene-knockout mutants, the gene associated with the phenotype of mutant NY303 was identified. This gene encodes a global regulator, Lrp. A mutant, YH01, deficient in Lrp was isolated and examined in vitro, in vivo and ex vivo to find the affected virulence mechanisms. The target genes of Lrp were further identified by comparing the transcriptomes, which were determined by RNA-seq, of strain YJ016 and mutant YH01. The promoters bound by Lrp were identified by genome footprinting-sequencing, and those related with virulence were further examined by electrophoretic mobility shift assay. RESULTS: A mutation in lrp was shown to be associated with the reduced cytotoxicity, chemotaxis and virulence of mutant NY303. Mutant YH01 exhibited a phenotype resembling that of mutant NY303, and was defective in colonization in the mouse and growth in mouse serum, but not the antiphagocytosis ability. 596 and 95 genes were down- and up-regulated, respectively, in mutant YH01. Many of the genes involved in secretion of the MARTX cytotoxin, chemotaxis and iron-acquisition were down-regulated in mutant YH01. The lrp gene, which was shown to be negatively autoregulated, and 7 down-regulated virulence-associated genes were bound by Lrp in their promoters. A 14-bp consensus sequence, mkCrTTkwAyTsTG, putatively recognized by Lrp was identified in the promoters of these genes. CONCLUSIONS: Lrp is a global regulator involved in regulation of cytotoxicity, chemotaxis and iron-acquisition in V. vulnificus. Down-regulation of many of the genes associated with these properties may be responsible, at least partly, for loss of virulence in mutant NY303.

High Incidence of Axillary Web Syndrome among Breast Cancer Survivors after Breast Reconstruction.

OBJECTIVE: The aim of this study was to identify if breast reconstruction is a surgical risk factor for axillary web syndrome (AWS) in breast cancer (BC) patients. METHODS: The data of 207 patients who have been diagnosed with unilateral BC and who had mastectomy and lymph node dissection were retrospectively reviewed. Information of their clinical and pathological data, whether they had immediate -reconstruction and intraoperative radiotherapy, surgical methods, and postoperative complications during the 3 months after their surgery (AWS, lymphedema, seroma, and myofascial adhesion) were collected, and the incidence of AWS was compared between different surgical methods. RESULTS: The overall incidence of AWS was 48.8% in 207 patients. Of the 22 patients who received reconstruction, 19 developed AWS, yielding an incidence of 86%. Multivariate logistic regression modeling showed that patients who underwent reconstruction had a significantly higher incidence of AWS (odds ratio, 4.74), as did patients with postoperative complication of myofascial adhesion (odds ratio, 7.07). CONCLUSIONS: BC survivors after breast reconstruction are susceptible to AWS, and there is a significant association between myofascial adhesion and AWS. Our results can stimulate further investigation and provide an evidence base for the development of educational guidance for patients who plan to undergo breast reconstruction.