Jong Hwa Yum

Genetic diversity of chromosomal metallo-β-lactamase genes in clinical isolates of Elizabethkingia meningoseptica from Korea

This study was performed to characterize the chromosomal metallo-β-lactamases (MBLs) of Elizabethkingia meningoseptica isolated from Korea and to propose a clustering method of BlaB and GOB MBLs based on their amino acid similarities. Chromosomal MBL genes were amplified by PCR from 31 clinical isolates of E. meningoseptica. These PCR products were then cloned into a vector and electrotransformed into E. coli DH5α. Nucleotide sequencing was performed by the dideoxy chain termination method using PCR products or cloned DNA fragments. Antimicrobial susceptibilities were determined by the agar dilution method. PCR experiments showed that all 31 E. meningoseptica isolates contained both the blaB and the blaGOB genes. DNA sequence analysis revealed that E. meningoseptica isolates possessed seven types of blaB gene, including five novel variants (blaB-9 to blaB-13) and 11 types of blaGOB gene, including 10 novel variants (blaGOB-8 to blaGOB-17). The most common combination of MBL was BlaB-12 plus GOB-17 (n=19). Minimum inhibitory concentrations of imipenem and meropenem for the electrotransformants harboring novel BlaB and GOB MBLs were two- or four-fold higher than those for the recipient E. coli DH5α. BlaB and GOB MBLs were grouped in three and six clusters including fifteen novel variants, respectively, based on amino acid similarities.

Proteomic evaluation on antiplatelet activity of piperlongumine derived from Piper longum

Piperlongumine (PL) abundantly present in Piper longum fruits strongly inhibited platelet cell aggregation. Proteomic studies using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and LC-MS/MS analysis showed that PL inhibited collagen-induced aggregation in rabbit platelet cells induced by collagen. Addition of PL protected aggregation of rabbit platelet cells from collagen induction and mediated proteomic changes as 33 proteins decreased and 24 proteins increased. Coagulation factor and fibrinogen were down-regulated and they are involved in aggregation of the platelet cells. Antithrombogenic effect of PL was determined using mice with an i.v. injection of a mixture of collagen and epinephrine. Protection rate of PL on thrombogenic effect of the mixtures was up to 47.9% and it was 8.6% higher than that of aspirin. Taken together, these results strongly suggest that PL is considered as a potent medicine for treating unexpected platelet cell aggregation.

Chromosomal cephalosporinase in Enterobacter hormaechei as an ancestor of ACT-1 plasmid-mediated AmpC β-lactamase.

In this study of the diversity of AmpC β-lactamase in clinical isolates of Enterobacter spp., a strain was found carrying the plasmid-mediated AmpC β-lactamase ACT-1 gene on its chromosome. The strain was identified as Enterobacter hormaechei using phylogenetic analysis of 16S rRNA and hsp60 genes. In addition, the species was confirmed by DNA-DNA hybridization. The genetic environment of the bla(ACT-1) gene was characterized, including the ampR and ampG genes, using a two-step PCR. The amino acid sequences of AmpR at serine 35, arginine 86, glycine 102, aspartic acid 135 and tyrosine 264 were conserved. Measurement of the transcription level of the bla(ACT-1) gene using real-time quantitative PCR showed that it increased 1.98-fold following cefoxitin induction. These results suggest that the plasmid-mediated bla(ACT-1) gene originated from the chromosome of E. hormaechei.

Loss of blaVIM-2 and blaIMP-1 during the Storage of Gram-Negative Bacilli, Antimicrobial Susceptibility of the Gene-Lost Strain, and Location of the Gene in the Cell

Background: Gram-negative bacilli can be stored in cystine tryptic agar (CTA) at room temperature for over 1 year, but we experienced a loss of imipenem resistance among VIM-2-producing isolates. The aims of this study were to determine the frequency of loss of IMP-1 and VIM-2 genes during storage in CTA at room temperature and to document any change in the MIC of antimicrobial agents and the location of the gene. Methods: Bacteria were isolated from clinical specimens at Severance Hospital collected from 1995-2000. Modified Hodge and double disk synergy tests were performed for screening of MBL-production isolates, and blaIMP-1 and blaVIM-2 were detected by PCR. Loss of resistance was tested in CTA at room temperature. PFGE and hybridization using a blaVIM-2 probe were carried out to determine the location of the VIM-2 gene. Results: When VIM-2and IMP-1-producing strains of eight P. aeruginosa and two Acinetobacter spp. were stored in CTA at room temperature, some isolates lost imipenem resistance after 3 days and 90% lost resistance after 15 weeks. Loss of resistance genes resulted in a decrease of the MIC of imipenem from 32-128 μg/mL to 0.5-8 μg/mL for P. aeruginosa, and from 32 μg/mL to 0.25-4 μg/mL for Acinetobacter spp. Hybridization of I-CeuI and S1-digested and PFGE suggested that VIM-2 genes are located on approximately 50-100 kb or 400 kb plasmids. Conclusion: Isolates may lose resistance genes when stored in CTA at room temperature. Therefore, it is necessary for MBL-production tests including the Modified Hodge test and double disk synergy test and detection of MBL genes. (Ann Clin Microbiol 2013;16: 120-125)

Detection of CTX-M-Type Extended-Spectrum β-Lactamase in Clinical Isolates of Chromosomal AmpC β-Lactamase-Producing Enterobacteriaceae from Korea and Their Molecular Characteristics

Background: Clinical isolates of AmpC β-lactamaseproducing Enterobacteriaceae were evaluated to determine the prevalence of CTX-M extended-spectrum β-lactamases (ESBLs) and their genetic environments. Methods: A total of 250 non-duplicate isolates of Eneterobacter aerogenes, E. cloacae, Citrobacter freundii, Serratia marcescens and Morganella morganii were collected at a Korean hospital. ESBL production was determined by double disk synergy test. For ESBL producers, bla genes were sequenced and blaCTX-M environment was characterized by PCR mapping and sequencing. Results: Among the 250 isolates 29 (11.6%) produced ESBL, and 14 of the 29 isolates produced CTX-M ESBLs, including CTX-M-9 by 8 isolates, CTX-M-3 by 4 isolates, CTX-M-12 by 1 isolate, and CTX-M-14 by 1 isolate. ISEcp1 was present upstream of blaCTX-M-3, 12, and 14. Three of the four CTXM-3 producers had the same genetic environment (pemK-ISEcp1-blaCTX-M-3-orf477-mucA). An IS903-like element was found downstream of blaCTX-M-14. ISCR1 was identified upstream of blaCTX-M-9 and ISCR1 and blaCTX-M-9 were located on sul1-type class 1 integron. The variable region between the 5’-CS and the first 3’-CS contained dfrA16 and aadA2. Its structure was similar to that of In60, but our isolates did not have IS3000 or second 3’-CS. Conclusion: CXT-M type ESBL was prevalent in AmpC β-lactamase-producing Enterobacteriaceae, particularly E. cloacae. blaCTX-M genes were associated with ISEcp1 or ISCR1. This is the first report on the genetic environment of blaCTX-M in Korean isolates. (Korean J Clin Microbiol 2008;11:90-97)

Trends in Pathogen Occurrence and Antimicrobial Resistance of Urinary Isolates in a Tertiary Medical Center over Ten Years: 2004~2013

To provide guidelines for the empirical treatment of urinary tract infections, we observed annual changes in the occurrence frequency and antimicrobial susceptibility of urinary isolates in a university hospital in the Chungbuk province, South Korea, over a period of 10 years (2004~2013). Escherichia coli (38.2%), Enterococcus faecalis (11.7%), Klebsiella pneumoniae (7.3%), Pseudomonas aeruginosa (4.3%), E. faecium (4.3%), and Staphylococcus aureus (4.1%) were commonly isolated urinary pathogens. The prevalence of E. coli, E. faecium and Streptococcus agalactiae were significantly higher in females (P < 0.001), whereas E. faecalis, P. aeruginosa and S. aureus were significantly more common in male patients (P < 0.001). E. coli mostly frequently showed resistance to ampicillin (67.94%), followed by trimethoprim/sulfamethoxazole (36.06%) and ciprofloxacin (26.84%). Over the studied time period, resistance rates of E. coli to ciprofloxacin significantly increased (20.44% to 33.55%). Moreover, extended-spectrum β-lactamase (ESBL) producing isolates also significantly increased in E. coli (4.2% to 18.3%) and K. pneumoniae (9.6% to 26.9%). In addition, the proportion of vancomycin-resistant Enterococcus facium (VRE) also increased (15.7% to 25.0%). In conclusion, over the last 10 years, the proportions of ciprofloxacin resistant E. coli and multidrug-resistant bacteria, such as ESBL and VRE have significantly increased. This trend must be strictly controlled and demonstrates the need for more updated guidelines for the treatment of urinary tract infections.

Comparison of the genetic structures surrounding qnrA1 in Korean Enterobacter cloacae and Chinese Escherichia coli Strains isolated in the early 2000s: Evidence for qnrA mobilization via Inc HI2 type plasmid

The flanking genetic structure of qnrA1 in Korean Enterobacter loacae was identical to that of the Chinese Escherichia coli strain, the first qnrA1-carrying strain reported in Asia. Analysis of restriction enzyme sites and Southern blot hybridization results showed that qnrA1 was transferred between E. cloacae and E. coli via Inc HI2 type plasmid.

The Attitude of Work Performance which Affects on the Work Capability for Clinical Dental Hygienist

This study from May 2014 March 2015 Gyeongnam, Busan material Dental disease (a) served on the original conduct a self survey of dental hygienists who are the duties of a dental hygienist attitude and ability to work to identify and duties attitude was to analyze the effects of the ability to work performed to provide basic information on ways to improve job performance and attitude, ability to work in a dental hygienist.As a result of performing the covariance structure analysis in order to establish the causal relation model which shows that the attitude of work performance can be affected on the work capability, attitude Received(November 26, 2015), Review request(November 27, 2015), Review Result(1st: December 13, 2015, 2nd: December 30, 2015) Accepted(January 09, 2016), Published(January 31, 2016) 330-705 Dept. Health Administration, Baekseok Culture Univ., Munam-ro, Dongnam-gu, Cheonan, Chungnam, Korea email: bellten@bscu.ac.kr 617-701 Dept. Dental Hygiene, Kyungnam College of information & technology, Busan-City, Seoul, Korea email: kjh3651@hanmail.net 614-714 Dept. of Clinical laboratory Science Dongeui Univ., Gaya 1-dong, Busanjin-gu, Busan, Korea email: auxotype@deu.ac.kr 210-702 Dept. Dental Hygiene, Kangnung-Wonju National Univ., Jibyeon-dong, Gangneung-si, Gangwon-do, Korea email: edelweiss-71@daum.net (Corresponding Author) 614-714 Dept. Dental Hygiene, Dongeui Univ., Gaya 1-dong, Busanjin-gu, Busan, Korea email: khj1126@deu.ac.kr The attitude of work performance which affects on the work capability for clinical dental hygienist Copyright c 2016 HSST 154 of work performance shows significant effect on the work performance (CR=8.711, p<0.001). On the other hand, the power of explanation (SMC) for emotional work evaluation shows the value of 61.2%. Also, the attitude of work performance for oral hygienists is absolutely affecting on their work capability. Therefore, countermeasure which can be lead on their healthy and stable workshop is to be needed.