Complementary Regulation of BfmRS Two-Component and AbaIR Quorum Sensing Systems to Express Virulence-Associated Genes in .

expresses various virulence factors to adapt to hostile environments and infect susceptible hosts. This study investigated the regulatory network of the BfmRS two-component and AbaIR quorum sensing (QS) systems in the expression of virulence-associated genes in ATCC 17978. The Δ mutant exhibited a significant decrease in surface motility, which presumably resulted from the low expression of and - gene cluster.

Clonal change of carbapenem-resistant Acinetobacter baumannii isolates in a Korean hospital.

The expansion of specific carbapenem-resistant Acinetobacter baumannii (CRAB) clones is a global concern due to its therapeutic difficulty and epidemicity. To understand the prevalence of CRAB isolates in a Korean hospital, we investigated the epidemiological characteristics of 96 CRAB isolates between 2016 and 2018, including the sequence types (STs), antimicrobial susceptibility, and genetic background of resistance to carbapenems and aminoglycosides. Six STs were identified using the Oxford multilocus sequence typing scheme; ST191 (n = 8), ST208 (n = 12), ST229 (n = 11), and ST369 (n = 21) were previously identified clones in the study hospital, whereas gpi variants of ST208, ST451 (n = 34) and ST784 (n = 10), were emerging clones.

The role of Zur-regulated lipoprotein A in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles in Acinetobacter baumannii.

Background: Zinc uptake-regulator (Zur)-regulated lipoprotein A (ZrlA) plays a role in bacterial fitness and overcoming antimicrobial exposure in Acinetobacter baumannii. This study further characterized the zrlA gene and its encoded protein and investigated the roles of the zrlA gene in bacterial morphology, antimicrobial susceptibility, and production of outer membrane vesicles (OMVs) in A. baumannii ATCC 17978.

Effects of an extrinsic motivator on the evaluation of cognitive and daily living functions in patients with schizophrenia.

We investigated the effect of an extrinsic motivator on the MATRICS Consensus Cognitive Battery (MCCB) and UCSD Performance-Based Skills Assessment (UPSA) scores, which assess cognitive and daily living functions, in patients with schizophrenia. We enrolled 60 clinically stable patients with schizophrenia and allocated them to the motivator or control group. We conducted baseline assessments of cognitive function using the MCCB, daily living function using the UPSA, clinical symptoms, and psychosocial characteristics in both groups.

The sensor kinase BfmS controls production of outer membrane vesicles in Acinetobacter baumannii.

Background: Acinetobacter baumannii is an important opportunistic pathogen responsible for various nosocomial infections. The BfmRS two-component system plays a role in pathogenesis and antimicrobial resistance of A. baumannii via regulation of bacterial envelope structures.

Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii isolates from a Korean hospital that carry bla.

To elucidate the epidemicity of carbapenem-resistant Acinetobacter baumannii (CRAB), we investigated the antimicrobial susceptibility, the genetic basis of antimicrobial resistance, and the ability to form biofilms of 147 CRAB isolates collected between 2013 and 2015 from a Korean hospital based on sequence types (STs). Six different STs were identified: ST191 (n=47) and ST208 (n=36) were clones that had already been identified in the study hospital, whereas ST229 (n=28), ST369 (n=18), ST357 (n=17), and ST552 (n=1) were previously unknown. All the CRAB isolates exhibited an extensively drug-resistance.

Antibacterial Activity of Hibicuslide C on Multidrug-Resistant Pseudomonas aeruginosa Isolates.

Pseudomonas aeruginosa is a gram-negative bacterium that is frequently related to natural resistance to many drugs. In this work, the inhibition of growth against P. aeruginosa and multidrug-resistant P.

Dermabacter jinjuensis sp. nov., a novel species of the genus Dermabacter isolated from a clinical specimen.

A Gram-stain-positive, catalase-positive, facultatively anaerobic, non-motile, coryneform bacterium, designated strain 32, was isolated from a closed pus sample from a patient having finger necrosis in Korea. Strain 32 was considered as representing a novel species according to its initial identification by matrix-assisted laser desorption/ionization-time-of-flight MS. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 32 belonged to the genus Dermabacter and was closely related to Dermabacter hominis DSM 7083 (=ATCC 49369) (98.

Outer membrane Protein A plays a role in pathogenesis of Acinetobacter nosocomialis.

Acinetobacter nosocomialis is an important nosocomial pathogen that causes a variety of human infections. However, the specific virulence factors of this microorganism have not yet been determined. We investigated the role of outer membrane protein A (OmpA) in the pathogenesis of A.

Mutational inactivation of OprD in carbapenem-resistant Pseudomonas aeruginosa isolates from Korean hospitals.

This study investigated the mechanisms underlying the carbapenem resistance of bloodstream isolates of Pseudomonas aeruginosa obtained from two Korean hospitals. Of the 79 P. aeruginosa isolates, 22 and 21 were resistant to imipenem and meropenem, respectively.

Genetic basis of antimicrobial resistance and clonal dynamics of carbapenem-resistant Acinetobacter baumannii sequence type 191 in a Korean hospital.

This study investigated the genetic basis of antimicrobial resistance and the epidemiological characteristics of 125 carbapenem-resistant Acinetobacter baumannii (CRAB) isolates collected from 2011 to 2012 in a Korean hospital. All CRAB isolates showed an extensively drug-resistant phenotype, but were susceptible to tigecycline. The blaOXA-23 and armA genes were mainly responsible for resistance to carbapenems and aminoglycosides, respectively.

Acinetobacter baumannii outer membrane vesicles elicit a potent innate immune response via membrane proteins.

Acinetobacter baumannii is increasingly becoming a major nosocomial pathogen. This opportunistic pathogen secretes outer membrane vesicles (OMVs) that interact with host cells. The aim of this study was to investigate the ability of A.

Emergence and spread of carbapenem-resistant Acinetobacter baumannii sequence type 191 in a Korean hospital.

Emergence and spread of specific carbapenem-resistant Acinetobacter baumannii (CRAB) clones cause a serious therapeutic problem. This study was aimed to investigate the clonal diversity and genetic basis of antimicrobial resistance among the 69 CRAB isolates from 2009 to 2010 in a Korean hospital. All CRAB isolates were found to be sequence type (ST) 2 using the Institute Pasteur's multilocus sequence typing (MLST) scheme, but classified into two sequence groups and nine pulsotypes.

Involvement of curli fimbriae in the biofilm formation of Enterobacter cloacae.

In this study, we examined the biofilm forming ability, the mRNA expression of curli genes and the morphologies of curli fimbriae and biofilms in clinical isolates of Enterobacter cloacae. The csgBA operon was found in 11 (78.6%) of the 14 isolates.

Staphylococcus aureus produces membrane-derived vesicles that induce host cell death.

Gram-negative bacteria produce outer membrane vesicles that play a role in the delivery of virulence factors to host cells. However, little is known about the membrane-derived vesicles (MVs) produced by gram-positive bacteria. The present study examined the production of MVs from Staphylococcus aureus and investigated the delivery of MVs to host cells and subsequent cytotoxicity.

Emergence of 16S rRNA methylase gene armA and cocarriage of bla(IMP-1) in Pseudomonas aeruginosa isolates from South Korea.

Of the 100 multidrug-resistant Pseudomonas aeruginosa isolates from a Korean hospital, 14 isolates that were resistant to all aminoglycosides tested carried 16S rRNA methylase gene armA. Fourteen armA-positive isolates were classified into 8 pulsotypes. Seven armA-positive isolates cocarried bla(IMP-1).

Investigation of the requirements of 'good teaching' to improve teaching professionalism in medical education.

Purpose: The purpose of this study is to survey the awareness of faculty (F) and students (S) on 'good teaching' and to analyze an example of good lesson, finally to identify the requirements of 'good teaching' in medical education.

Methods: Quantitative and qualitative methods were applied simultaneously. First, survey using a questionnaire was analyzed by frequency analysis and verified using chi-square-test, Mann-Whitney test.

Serum resistance of Acinetobacter baumannii through the binding of factor H to outer membrane proteins.

Bacteremia is a common systemic disease caused by Acinetobacter baumannii, an important hospital-acquired pathogen among critically ill patients. The complement system is central to innate immune defense against invading bacteria in the blood. The present study investigated the susceptibility of clinical A.

Emergence of a new mutation and its accumulation in the topoisomerase IV gene confers high levels of resistance to fluoroquinolones in Escherichia coli isolates.

Mutations in DNA gyrase and topoisomerase IV genes are the main mechanisms of resistance to quinolones. In this study, we determined mutations in gyrA, gyrB, parC and parE among 57 ciprofloxacin-resistant Escherichia coli isolates from a South Korean hospital and analysed the relationship between the minimal inhibitory concentrations (MICs) of fluoroquinolones and mutations in the topoisomerase IV gene. All ciprofloxacin-resistant E.

Genetic basis of resistance to aminoglycosides in Acinetobacter spp. and spread of armA in Acinetobacter baumannii sequence group 1 in Korean hospitals.

A total of 75 Acinetobacter isolates resistant to all available aminoglycosides obtained from 2 Korean hospitals were studied for the genetic basis of resistance to aminoglycosides. The MIC(50) and MIC(90) of Acinetobacter baumannii isolates (n = 61) to amikacin, gentamicin, isepamycin spectinomycin, streptomycin, and tobramycin were higher than those of Acinetobacter genomic species 13TU isolates (n = 14). Genes encoding aminoglycoside-modifying enzymes, ant(3")-Ia, aac(6')-Ib, aph(3')-1a, aac(3)-Ia, and aph(3')-VI, and 16S ribosomal RNA (rRNA) methylase armA were detected.

Characterization of conjugative plasmids carrying antibiotic resistance genes encoding 16S rRNA methylase, extended-spectrum beta-lactamase, and/or plasmid-mediated AmpC beta-lactamase.

In this study, we identified extended-spectrum beta-lactamase (ESBL) and plasmid-mediated AmpC beta-lactamase which were associated with 16S rRNA methylase gene on the conjugative plasmid. Among 82 clinical isolates of Enterobacteriaceae that carry 16S rRNA methylase gene (64 strains, armA, and 18 strains, rmtB), bla(SHV-12) was detected either alone or combined with bla(DHA-1), bla(CTX-M-3), and bla(CTX-M-14) in 30 strains carrying armA and 6 strains carrying rmtB. The bla(CTX-M-3) was detected in 13 of 64 strains carrying armA but no strains carrying rmtB.

Acinetobacter baumannii invades epithelial cells and outer membrane protein A mediates interactions with epithelial cells.

Background: Acinetobacter baumannii is a nosocomial pathogen of increasing importance, but the pathogenic mechanism of this microorganism has not been fully explored. This study investigated the potential of A. baumannii to invade epithelial cells and determined the role of A.

Nuclear translocation and DNAse I-like enzymatic activity of Acinetobacter baumannii outer membrane protein A.

Acinetobacter baumannii outer membrane protein A (AbOmpA) is a potential virulence factor that induces host cell death. Based on previous findings that AbOmpA translocated into the nuclei of host cells, the cell-death mechanism of AbOmpA through the nuclear targeting was investigated. Acinetobacter baumannii secreted AbOmpA in in vitro culture.

Plasmid-mediated quinolone resistance determinants qnrA, qnrB, and qnrS among clinical isolates of Enterobacteriaceae in a Korean hospital.

Screening of 368 consecutive nonreplicate clinical isolates of Enterobacteriaceae resistant to nalidixic acid and at least one extended-spectrum beta-lactam revealed the presence of qnrA, qnrB, and qnrS determinants, and identified novel qnrB variants, in Citrobacter freundii isolates. This study also revealed, for the first time, the linkage of qnrB, armA, and extended-spectrum and/or AmpC-type beta-lactamase genes on large conjugative plasmids.