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Background Doxycycline is currently the most frequently used treatment in patients with scrub typhus. However, doxycycline-resistant strains have been found, necessitating the development of a new treatment. Rifampin is known to be effective even for such strains. Our aim in this study was to compare the effects of rifampin and doxycycline treatment in patients with scrub typhus in areas in which resistance to doxycycline has not been reported. Methods Patients admitted to Chosun University Hospital and regional network hospitals between 2007 and 2009 with a body temperature ≥37.5°C and suspected to have scrub typhus were randomly assigned to 1 of 2 treatment groups: a group administered doxycycline 100 mg twice daily for 5 days and a group administered rifampin 600 mg once daily for 5 days. For treatment outcomes, fever, headache, muscle ache, and rash clearance times were compared between the groups. Results The rifampin and doxycycline groups showed equivalence in all treatment outcomes evaluated. The proportions of patients with fever clearance within 48 hours were similar between groups. Furthermore, there was no significant difference in the occurrence of side effects following drug administration between groups. Conclusions On the basis of the finding that equivalent treatment effects and safety were found in patient groups that received 600 mg of rifampin and 200 mg of doxycycline, respectively, for 5 days to treat scrub typhus, rifampin may be considered an alternative treatment to doxycycline. Clinical Trials Registration NCT00568711. [ABSTRACT FROM AUTHOR]

Bacterial swarming constitutes a good in vitro model for surface adherence and colonization, and is accompanied by expressions of virulence factors related to invasiveness. In this study, it was determined that Vibrio vulnificus swarming was abolished by mutation of the vvpE gene encoding a metalloprotease VvpE and this swarming defect was recovered by complementation of the vvpE gene. Expression of the vvpE gene began simultaneously with the beginning of swarming and increased along with expression of the luxS gene encoding the synthase of the precursor of quorum-sensing signal molecule autoinducer 2, and this increased vvpE expression was decreased by mutation of the luxS gene. Moreover, VvpE destroyed IgA and lactoferrins, which are responsible for mucosal immunity. These results suggest that VvpE may play important roles in the surface adherence and colonization of V. vulnificus by facilitating swarming and in the mucosal invasion of V. vulnificus by destroying IgA and lactoferrin. [ABSTRACT FROM AUTHOR]

Background Scrub typhus is a mite-borne infectious disease caused by Orientia tsutsugamushi. There have been few follow-up studies assessing antibody titers using serologic tests from various commercial labs. Methods A prospective investigation to assess antibody titers of scrub typhus patients and seroprevalence for health checkup individuals were evaluated. The antibody titers of former patients diagnosed with scrub typhus at least 1 year and a maximum of 13 years were also investigated. The following tests were performed simultaneously: (i) immunofluorescence antibody assays (IFAs) that detect immunoglobulin(Ig) M and IgG, (ii) IFA that detects total Ig by a commercial lab, (iii) antibody tests using two commercially available kits. Results In prospective analyses with cutoff values set to ≥1:16 for IgM, ≥1:256 for IgG based on the KCDC's criteria, and ≥1:40 for total Ig. The antibody positive rates of 102 confirmed scrub typhus patients were 44%, 35.3%, and 57.6%, respectively, in the first week after symptom onset. Among 91 former patients recovered, the follow-up IgM, IgG, and total Ig positivity rates were 38.5% (35/91), 22% (20/91), and 76.9% (70/91), respectively. In overall cohort of 216 health checkup subjects, 4.2% (9/216) IgM and 0% (0/216) IgG seroprevalence was observed. Conclusion The IFA from KCDC and commercial lab, and rapid commercial kits cannot differentiate between former patients recovered from scrub typhus and current scrub typhus. In Korea and other countries where low antibody cut-off titer values have been used as criteria for diagnosing and reporting scrub typhus, upward adjustments of cut-off values may be necessary. Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]

Background Scrub typhus, anaplasmosis, and leptospirosis are well-known diseases that are considered common, widespread rodent-borne infectious diseases Methods This study investigated the prevalence of Orientia tsutsugamushi , Anaplasma phagocytophilum , and Leptospira interrogans in wild rodents through molecular detection using organ samples and through serological assay using blood samples of mice collected from two distinct sites in Gwangju Metropolitan City, Republic of Korea (ROK). Results A total of 47 wild rodents, identified as Apodemus agrarius (A. agrarius), were captured from June to August 2016. The seroprevalence of antibodies against bacterial pathogens in A. agrarius sera was analyzed; 17.4% (8/46) were identified as O. tsutsugamushi through indirect immunofluorescence assay and 2.2% (1/46) were identified as Leptospira species through passive hemagglutination assay. Using polymerase chain reaction, the spleen, kidney and blood samples were investigated for the presence of O. tsutsugamushi, A. phagocytophilum , and L. interrogans. Out of the 47 A. agrarius , 19.1% (9/47) were positive for A. phagocytophilum and 6.4% (3/47) were positive for L. interrogans , while none were positive for O. tsutsugamushi. Four out of 46 (8.7%) blood samples, six out of 45 (13.3%) spleen samples, and one out of 47 (2.1%) kidney samples were positive for A. phagocytophilum. Three out of 47 (6.4%) kidney samples were positive for L. interrogans. The sequencing results of PCR positive samples demonstrated >99% similarity with A. phagocytophilum and L. interrogans sequences Conclusion A. phagocytophilum was mostly detected in the spleen, whereas L. interrogans was mostly detected in the kidneys. Notably, A. phagocytophilum and L. interrogans were detected in A. agrarius living in close proximity to humans in the metropolitan suburbans. The results of this study indicate that rodent-borne bacteria may be present in wild rodents in the metropolitan suburban areas of ROK Disclosures All authors: No reported disclosures. [ABSTRACT FROM AUTHOR]

Abstract: In order to elucidate the role of Vibrio vulnificus metalloprotease VvpE in the uptake of iron from human transferrin, we constructed a VvpE-deficient mutant and a merozygotic vvpE-transcriptional reporter from the wild type strain MO6-24/O. All three strains were able to grow only in deferrated Heart Infusion broth (DF-HI) with human holotransferrin (HT), but not in DF-HI containing partially iron-saturated transferrin or apotransferrin, without noticeable differences among the strains. All strains consumed most iron in the early growth phase. Both the transcription and extracellular production of VvpE proceeded at undetectable levels when bacterial growth was severely retarded in the DF-HI. When HT or FeCl3 was added to the DF-HI, the retarded bacterial growth was restored and vvpE transcription dramatically increased in the late growth phase, but the extracellular VvpE production was negligible as compared to its transcription. All strains were unable to degrade HT even in normal HI broth containing HT, in which extracellular VvpE activity was remarkably high. The uptake of iron from HT in all strains was consistent with the production of catechol-siderophore rather than hydroxamate-siderophore. Similar results were also observed when clinical isolates from septicemic patients were used. In conclusion, we determined that VvpE was not directly involved in the siderophore-mediated iron-uptake from human transferrin. In addition, the discrepancy between the transcription and extracellular production of VvpE suggests that additional posttranscriptional events are involved in the extracellular production of VvpE. [Copyright &y& Elsevier]

Abstract: Vibrio vulnificus, a halophilic estuarine bacterium, causes a fatal septicemia and necrotizing wound infection. To investigate the role of cAMP in V. vulnificus virulence regulation, an in-frame deletion mutant of the cya gene encoding adenylate cyclase was constructed. The cya null mutation resulted in a pleiotropic change of virulence phenotypes. The production of hemolysin and protease, the motility, and the cytotoxicity were decreased by the cya mutation. The defects in the cya mutant were functionally complemented in trans by a plasmid carrying the wild type cya allele. The V. vulnificus cya mutant exhibited a 100-fold increase in LD50 to mice. The result indicates that cAMP plays an essential role in the global regulation of V. vulnificus virulence. [Copyright &y& Elsevier]