Coactivation of Vibrio vulnificus putAP operon by cAMP receptor protein and PutR through cooperative binding to overlapping sites.

The cAMP receptor protein (CRP) positively regulates the expression of Vibrio vulnificus putAP genes encoding a proline dehydrogenase and a proline permease. In the present study, an open reading frame encoding PutR was identified downstream of the putAP genes and a mutational analysis revealed that the PutR protein was also involved in regulating the putAP transcription by activating Pput promoter. Although CRP acts as a primary activator and the influence of PutR on Pput is mediated by CRP, the level of Pput activity observed when PutR and CRP functioned together was greater than the sum of Pput activities achieved by each activator alone.

Cyclo(Phe-Pro) modulates the expression of ompU in Vibrio spp.

Vibrio vulnificus was found to produce a chemical that induced the expression of Vibrio fischeri lux genes. Electron spray ionization-mass spectrometry and 1H nuclear magnetic resonance analyses indicated that the compound was cyclo(L-Phe-L-Pro) (cFP). The compound was produced at a maximal level when cell cultures reached the onset of stationary phase.

Risk factors and outcome for breakthrough candidaemia in patients with cancer.

While candidaemia that develops during systemic antifungal prophylaxis or therapy [breakthrough (BT) candidaemia] has been reported increasingly, the risk factors and outcome of BT candidaemia are not yet known definitely. We evaluated a consecutive series of cancer patients with candidaemia at Asan Medical Center during 6 years to identify risk factors and outcome in BT candidaemia comparing with non-BT candidaemia. Fifty-four episodes of candidaemia in cancer patients diagnosed during this period were reviewed retrospectively.

Identification of the Vibrio vulnificus wbpP gene and evaluation of its role in virulence.

A wbpP gene encoding a putative UDP-N-acetyl-D-glucosamine C(4) epimerase was identified and cloned from Vibrio vulnificus. The functions of the wbpP gene, assessed by the construction of an isogenic mutant and by evaluating its phenotype changes, demonstrated that WbpP is essential in both the pathogenesis and the capsular polysaccharide biosynthesis of V. vulnificus.

CadC activates pH-dependent expression of the Vibrio vulnificus cadBA operon at a distance through direct binding to an upstream region.

The Vibrio vulnificus cadBA genes were transcribed as a transcriptional operon by a single promoter, P(cadBA), which was activated by CadC in a pH-dependent manner. A direct interaction between CadC and the P(cadBA) DNA was demonstrated, and a CadC binding site centered at -233.5 was mapped by deletion analyses of P(cadBA) and confirmed by a DNase I protection assay.

Increasing incidence of quinolone resistance in human non-typhoid Salmonella enterica isolates in Korea and mechanisms involved in quinolone resistance.

Objectives: We investigated the trends of nalidixic acid resistance in human non-typhoid Salmonella enterica in a Korean population, and examined some possible mechanisms involved in this resistance.

Methods: A total of 261 clinical strains were tested. For all strains, the MICs of nalidixic acid were determined.

Characterization of erythromycin-resistant Streptococcus pneumoniae in Korea, and In Vitro activity of telithromycin against erythromycin-resistant Streptococcus pneumoniae.

To characterize the phenotypes and genotypes of erythromycin-resistant clinical isolates of Streptococcus pneumoniae in Korea and to evaluate the in vitro activity of telithromycin against these erythromycin-resistant isolates, we tested a total of 676 isolates of S. pneumoniae collected from 1997 to 2002 in a tertiary hospital in Seoul, Republic of Korea. MICs for erythromycin and telithromycin were determined by the agar dilution method.

Synthetic bile acid derivatives induce apoptosis through a c-Jun N-terminal kinase and NF-kappaB-dependent process in human cervical carcinoma cells.

Recently, we have reported that a synthetic derivative of ursodeoxycholic acid (UDCA), HS-1183, and those of chenodeoxycholic acid (CDCA), HS-1199 and HS-1200, induced apoptosis in human breast carcinoma cells through a p53-independent pathway. Here, we present that the synthetic bile acid derivatives induce apoptosis in SiHa human cervical carcinoma cells as well. The parental compounds, UDCA and CDCA, exhibited no significant effect on the cell viability at the concentration ranges tested.

Inhibitory effects of costunolide on the telomerase activity in human breast carcinoma cells.

Costunolide, a natural sesquiterpene compound, has been known having cytotoxic and chemopreventive effects on various human cancer cells. In the present study, we examined the effects of costunolide on telomerase activity and on the components of telomerase in MCF-7 (wild-type p53) and MDA-MB-231 (mutant p53) cells. We found that costunolide inhibited the growth and telomerase activity of MCF-7 and MDA-MB-231 cells in a concentration- and time-dependent manner.

Detection of qnr in clinical isolates of Escherichia coli from Korea.

qnr was detected in 2 of 260 Escherichia coli clinical isolates collected from a Korean hospital during the period 2001 to 2003. The two strains were not clonally related. qnr was located in In4 family class 1 integrons of original structure, downstream of orf513 and upstream from another resistance gene (dfrA3b) and a gene of unknown function (orf105).

Risk factors for the acquisition of carbapenem-resistant Klebsiella pneumoniae among hospitalized patients.

The isolation of carbapenem-resistant Klebsiella pneumoniae (CRKP) has been increasingly reported. However, no study analyzing potential risk factors for the acquisition of CRKP has been published as of now. We therefore performed a case-control study to determine the risk factors for the acquisition of CRKP.

Thrombin-induced oxidative stress contributes to the death of hippocampal neurons in vivo: role of microglial NADPH oxidase.

The present study investigated whether thrombin, a potent microglial activator, can induce reactive oxygen species (ROS) generation through activation of microglial NADPH oxidase and if this may contribute to oxidative damage and consequent neurodegeneration. Seven days after intrahippocampal injection of thrombin, Nissl staining and immunohistochemistry using the neuronal-specific nuclear protein NeuN revealed a significant loss in hippocampal CA1 neurons. In parallel, thrombin-activated microglia, assessed by OX-42 and OX-6 immunohistochemistry, and ROS production, assessed by hydroethidine histochemistry, were observed in the hippocampal CA1 area in which degeneration of hippocampal neurons occurred.

Clinical significance of untreated Candida species isolated from ascites in cirrhotic patients.

The clinical significance of Candida species isolated from cirrhotic ascites is still unknown. We reviewed the clinical and laboratory features of all cirrhotic patients whose ascites samples were positive for Candida species. A total of 21 cirrhotic patients was identified.

Role of flagellum and motility in pathogenesis of Vibrio vulnificus.

To assess the role of the flagellum which was detected by immunoscreening of surface proteins of Vibrio vulnificus, an flgE-deleted mutant was constructed and tested for its pathogenicity. The ability of this nonmotile mutant to adhere to INT-407 cells and its role in biofilm were decreased, as was its lethality to mice.

Isolation and characterization of rpoS from a pathogenic bacterium, Vibrio vulnificus: role of sigmaS in survival of exponential-phase cells under oxidative stress.

A gene homologous to rpoS was cloned from a fatal human pathogen, Vibrio vulnificus. The functional role of rpoS in V. vulnificus was accessed by using an rpoS knockout mutant strain.

Mistletoe lectin induces apoptosis and telomerase inhibition in human A253 cancer cells through dephosphorylation of Akt.

Mistletoe lectin has been reported to induce apoptosis in different cancer cell lines in vitro and to show antitumor activity against a variety of tumors in animal models. We previously demonstrated the Korean mistletoe lectin (Viscum album var. coloratum, VCA)-induced apoptosis by down-regulation of Bcl-2 and telomerase activity and by up-regulation of Bax through p53- and p21-independent pathway in hepatoma cells.

Risk factors for acquisition of imipenem-resistant Acinetobacter baumannii: a case-control study.

Risk factors for the nosocomial occurrence of imipenem-resistant Acinetobacter baumannii (IRAB) were determined. A case-control study design was used for a comparison of two groups of A. baumannii-positive patients with control patients.

Clinical features and outcomes of bacteremia caused by Enterococcus casseliflavus and Enterococcus gallinarum: analysis of 56 cases.

The clinical significance and virulence potential of Enterococcus casseliflavus/flavescens and Enterococcus gallinarum are still uncertain. We retrospectively analyzed 56 cases of significant bacteremia caused by E. casseliflavus or E.

SmcR and cyclic AMP receptor protein coactivate Vibrio vulnificus vvpE encoding elastase through the RpoS-dependent promoter in a synergistic manner.

The putative virulence factors of Vibrio vulnificus include an elastase, the gene product of vvpE. We previously demonstrated that vvpE expression is differentially directed by two different promoters in a growth phase-dependent manner. The activity of the stationaryphase promoter (promoter S (PS)) is dependent on RpoS and is also under the positive control of cyclic AMP receptor protein (CRP).

Outcome of antibiotic therapy for third-generation cephalosporin-resistant Gram-negative bacteraemia: an analysis of 249 cases caused by Citrobacter, Enterobacter and Serratia species.

Two hundred and forty-nine patients with monomicrobial bacteraemia due to third-generation cephalosporin (TGC)-resistant Citrobacter freundii (42), E. aerogenes (23), E. cloacae (143), and Serratia marcescens (41) were analyzed for antibiotic therapy used and outcome.

Characterization of the Vibrio vulnificus putAP operon, encoding proline dehydrogenase and proline permease, and its differential expression in response to osmotic stress.

The Vibrio vulnificus putAP genes encoding a proline dehydrogenase and a proline permease are transcribed in the same direction. Proline dehydrogenase activity and the level of putA transcript were determined to reach a maximum in exponential phase and were then repressed when growth slowed down. Northern blotting and primer extension analyses revealed that transcription of putAP genes results in two different transcripts, transcript A (putA transcript) and transcript AP (putAP transcript).

Identification and isolation of foot-and-mouth disease virus from primary suspect cases in Korea in 2000.

The Republic of Korea had been free from foot and mouth disease (FMD) since 1934, until a recent outbreak in 2000. From March to April 2000, a total of 15 FMD outbreaks due to the serotype O virus were recorded. Coincidental outbreaks of FMD in cattle or pigs by the serotype O virus were reported in the region, including Taiwan, China, Japan, Russia and Mongolia.

Serratia bacteremia in a large university hospital: trends in antibiotic resistance during 10 years and implications for antibiotic use.

Objective: To identify antibiotic resistance trends and risk factors for resistance of Serratia species to third-generation cephalosporins.

Design: Retrospective survey of medical records.

Setting: A 2,200-bed, tertiary-care hospital.

Promoter analysis and regulatory characteristics of vvhBA encoding cytolytic hemolysin of Vibrio vulnificus.

Cytolytic hemolysin, a gene product of vvhA, is a putative virulence factor of the pathogenic bacterium Vibrio vulnificus. We have previously shown that hemolysin production is repressed by adding glucose to culture media and that production can be restored by adding cAMP. In this study, hemolysin activity and the level of vvh transcript were determined to reach a maximum in late exponential phase and were repressed when cells entered stationary phase.

Identification of the cadBA operon from Vibrio vulnificus and its influence on survival to acid stress.

By a transposon-tagging method, cadBA genes encoding a lysine/cadaverin antiporter and a lysine decarboxylase were identified and cloned from Vibrio vulnificus. The deduced amino acid sequences of cadBA were 64-97% similar to those reported from other Enterobacteriaceae. Functions of cadBA genes on acid tolerance were assessed by comparing acid tolerances of V.