• Natural Product Sciences
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• v.25 no.2
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• pp.172-180
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• 2019

Infections with Pseudomonas aeruginosa are difficult to treat not only because it is often associated with multidrug-resistant infections but also it is able to form biofilm. The aim of this study was to evaluate the antibiofilm and anti-Quorum Sensing (QS) activities of Thymbra capitata essential oils (EOs) against Beta Lactamase (BL) producing P. aeruginosa and the reference strain P. aeruginosa 10145. GC/MS analysis showed that thymol (23.25%) is the most dominant compound in T. capitata EOs. The MICs of T. capitata EOs against P. aeruginosa (BL) and P. aeruginosa 10145 were 1.11%. At sub MIC (0.041, 0.014 and 0.0046%), the EOs of T. capitata remarkably inhibited the biofilm formation of both strains tested and complete inhibition of the biofilm formation was reported at 0.041%. The EOs of T. capitata were found to inhibit the swarming motility, aggregation ability and hydrophobic ability of P. aeruginosa (BL) and P. aeruginosa 10145. Interestingly, the EOs of T. capitata reduce the production of three secreted virulence factors that regulated by QS system including pyocyanin, rhamnolipids and LasA protease. The potent antibiofilm and anti-QS activities of T. capitata EOs can propose it as a new antibacterial agent to control pseudomonas infections.

• Pediatric Infection and Vaccine
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• v.30 no.1
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• pp.47-54
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• 2023

With the widespread use of broad-spectrum antibiotics in clinical practice, the emergence of multidrug-resistant (MDR) gram-negative bacteria has become a global problem. The MDR Pseudomonas aeruginosa infection is especially difficult to treat and increases mortality in critically ill patients. Ceftolozane-tazobactam (Zerbaxa^TM) is a fifth-generation cephalosporin and beta-lactamase inhibitor that has proved to be effective for treating complicated urinary tract infections and complicated intra-abdominal infections caused by MDR P. aeruginosa. Herein, we report the first case of pediatric hematologic cancer in Korea that was successfully treated for MDR P. aeruginosa bacteremia with Ceftolozane-tazobactam.

• Archives of Plastic Surgery
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• v.34 no.6
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• pp.691-696
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• 2007

Purpose: The emergency of multi-drug resistant stains of bacteria represents a challenge in the field of plastic surgery. Especially, MRSA(methycillin-resistant Staphylococcus aureus) and Pseudomonas aeruginosa have strong pathogenicity as well as multi-drug resistance so that they have become a lot more problematic strains. This study has been planned to reduce the bacterial burden by applying $Acticoat^{(R)}$(Smith & Nephew Healthcare, Hull, England)dressing into the chronic wounds infected by multi-drug resistant strains and to facilitate their healing. Methods: Nanocrystalline silver dressings($Acticoat^{(R)}$) were applied to chronic wound infected by MRSA or Pseudomonas aeruginosa. Multi-drug resistant bacteria were smeared over a slide glass using sterilized cotton swabs and gram stains were performed directly before and after applying $Acticoat^{(R)}$ dressings at 1, 24, 48 and 72 hours. The gram-stained slides were observed using an optical microscope magnified 1000 times(${\times}1000$). The bacterial counts of the control group(0 hour) were compared to those of the experimental groups(1, 24, 48, and 72 hour). Paired T-test was used to assess a statistical significance. MRSA was cultured in two BAPs(blood agar plate) and two MacConkey plates with streak plate method. None were interventions on one culture plate, while on the other culture plate, $Acticoat^{(R)}$ was placed in a square shape and cultured for 72 hours at $37^{\circ}C$, then plates were examined. Pseudomonas aeruginosa was cultured in the same manner as MRSA. Results: There are the large amount of declination of bacterial counts with statistical significance after $Acticoat^{(R)}$ dressing. The bacteria grew in culture plate without specific intervention, but no bacteria grew in culture plate with applying of $Acticoat^{(R)}$ dressing. Conclusion: We believe that $Acticoat^{(R)}$ dressing could be used as an effective method of treating chronic wounds which are infected by multi-drug resistant organisms.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.408-420
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• 2016

This study proposes an alternative approach for the use of chitosan silver-based dressing for the control of foot infection with multidrug-resistant bacteria. Sixty-five bacterial isolates were isolated from 40 diabetic patients. Staphylococcus aureus (37%) and Pseudomonas aeruginosa (18.5%) were the predominant isolates in the ulcer samples. Ten antibiotics were in vitro tested against diabetic foot clinical bacterial isolates. The most resistant S. aureus and P. aeruginosa isolates were then selected for further study. Three chitosan sources were tested individually for chelating silver nanoparticles. Squilla chitosan silver nanoparticles (Sq. Cs-Ag⁰) showed the maximum activity against the resistant bacteria when mixed with amikacin that showed the maximum synergetic index. This, in turn, resulted in the reduction of the amikacin MIC value by 95%. For evaluation of the effectiveness of the prepared dressing using Artemia salina as the toxicity biomarker, the LC₅₀ was found to be 549.5, 18,000, and 10,000 μg/ml for amikacin, Sq. Cs-Ag⁰, and dressing matrix, respectively. Loading the formula onto chitosan hydrogel dressing showed promising antibacterial activities, with responsive healing properties for the wounds in normal rats of those diabetic rats (polymicrobial infection). It is quite interesting to note that no emergence of any side effect on either kidney or liver biomedical functions was noticed.

• Journal of Microbiology and Biotechnology
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• v.17 no.10
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• pp.1733-1737
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• 2007

A total of 2,280 nonduplicate clinical isolates of Pseudomonas aeruginosa, obtained nationwide from Korean non-tertiary care hospitals from 2002 to 2005, were identified and their susceptibilities to aminoglycosides, antipseudomonal penicillins, carbapenems, cephalosporins, monobactams, and quinolones were studied, together with their production of ${\beta}$-lactamases. Using disk diffusion and minimum inhibitory concentration tests, it was found that 2.9% of isolates were multidrug-resistant (MDR) P. aeruginosa. An EDTA-disk synergy test, PCR amplification with specifically designed primers, and direct sequencing of the PCR products showed that the $bla_{OXA-10}$, $bla_{VIM-2}$, $bla_{OXA-2}$, $bla_{OXA-17}$, $bla_{PER-1}$, $bla_{SHV-12}$, and $bla_{IMP-1}$ genes were carried by 34.3%, 26.9%, 3.0%,3.0%, 1.5%, 1.5%, and 1.5% of 67 MDR P. aeruginosa isolates, respectively. The prevalence of MDR P. aeruginosa was three-fold higher, compared with that from the United States. More than two types of ${\beta}$-lactamase genes were carried by 10.4% of isolates. The most prevalent ${\beta}$-lactamase genes were $bla_{VIM-2}$ and $bla_{OXA-10}$. This study is the first description of MDR P. aeruginosa trom non-tertiary care hospitals in Korea and the coexistence of the $bla_{VIM-2}$, $bla_{IMP-1}$, or $bla_{PER-1} in these clinical isolates.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.651-661
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• 2019

Targeting the pathogen viability using drugs is associated with development of drug resistance due to selective pressure. Hence, there is an increased interest in developing agents that target bacterial virulence. In this study, the inhibitory effect of ciclopirox, an antifungal agent with iron chelation potential, on the microbial virulence factors was evaluated in 26 clinical MDR Pseudomonas aeruginosa isolates collected from Alexandria Main University Hospital, a tertiary hospital in Egypt. Treatment with 9 ㎍/ml ciclopirox inhibited the hemolytic activity in 70% isolates, reduced pyocyanin production, decreased protease secretion in 46% isolates, lowered twitching and swarming motility, and decreased biofilm formation by 1.5- to 4.5-fold. The quantitative real-time PCR analysis revealed that treatment with ciclopirox downregulated the expression levels of alkaline protease (aprA) and pyocyanin (phzA1). Ciclopirox is used to treat hematological malignancies and the systemic administration of ciclopirox is reported to have adequate oral absorption with a satisfactory drug safety profile. It is important to calculate the appropriate clinical dose and therapeutic index to reposition ciclopirox from a topical antifungal agent to a promising virulence-modifying agent agent against P. aeruginosa, a problematic Gram-negative pathogen.

• Korean Journal of Clinical Laboratory Science
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• v.54 no.2
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• pp.119-124
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• 2022

Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are typical opportunistic pathogens. Moreover, these bacteria are known to possess multidrug-resistant (MDR) properties. This study investigates the antimicrobial activity of six fermented products, which have varying efficacies against P. aeruginosa, E. coli, and S. aureus. To identify novel candidate genes, differential expression analysis was performed using an annealing control primer. In the disk diffusion method, Fig vinegar (FV) and Diospyros kaki Thunb vinegar (DTV) showed the greatest increase in inhibition compared to other fermented products, whereas fermented Korean traditional nature herb (FKTNH) had no antibacterial effect. This study identified down-regulation of Escherichia coli O157:H7 ompW gene for outer membrane protein W, whereas gene for synthetic construct Lao1 gene for L-amino acid oxidase were up-regulated in E. coli treated with 5% FV. Consuming fermented vinegar helps prevent bacterial infections. Especially, FV and DTV are potentially useful alternative natural products for multidrug resistance. Furthermore, both are expected to be used as effective natural antimicrobial agents, such as disinfectants.

• Biomedical Science Letters
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• v.19 no.3
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• pp.245-253
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• 2013

To provide reference data or guideline for empirical treatment of bloodstream infection, we studied a change pattern in causative microorganisms and antimicrobial susceptibility in a general hospital at Gyeonggi province during five years. We retrospectively reviewed the frequency of causative microorganisms and antimicrobial susceptibility results of 5,782 microorganisms isolated from blood culture in a general hospital during the period from January 2008 to December 2012. The most common pathogens were Escherichia coli (14.7%), Staphylococcus aureus (7.5%), Streptococcus viridans group (4.9%), and Klebsiella pneumoniae (4.1%). The multiple microorganisms were isolated in 4.3% of bloodstream infection patients. The average contamination rate of blood culture during five years was 3.0%. Methicillin-resistant S. aureus (MRSA), vancomycin-resistant Enterococcus faecium (VRE), and penicillin-resistant Streptococcus pneumoniae were isolated at 62%, 27% and 11%, respectively. Cefotaxime-resistant E. coli and K. pneumoniae was 20% and 18%, respectively. Imipenem-resistant Pseudomonas aeruginosa (IRPA) and Acinetobacter baumannii (IRAB) was 25% and 66%, respectively. E. coli and S. aureus were most common pathogens isolated from blood culture for five years. The increase of multidrug-resistant microorganisms, such as MRSA, VRE, ESBL, IRPA and IRAB, requires more strict control of antibiotics and causes the need of the more updated guideline for the treatment of blood stream infection.

• Annals of Clinical Microbiology
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• v.21 no.4
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• pp.80-85
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• 2018

Background: The aim of this study was to comparatively evaluate the bactericidal effects of copper, brass (copper 78%, tin 22%), and stainless steel against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VREFM), and multidrug-resistant Pseudomonas aeruginosa (MRPA). Methods: The isolates (MRSA, VREFM, MRPA) used in this study were mixed wild type 3 strains isolated from patients treated at Uijeongbu St. Mary's Hospital in 2017. These strains showed patterns of multidrug resistance. The lyophilized strains were inoculated into and incubated for 24 hr in tryptic soy broth at $35^{\circ}C$. The initial bacterial inoculum concentration was adjusted to $10^5CFU/mL$. A 100-mL bacterial suspension was incubated in containers made of brass (copper 78%, tin 22%), copper (above 99% purity), and stainless steel at $35^{\circ}C$. Viable counts of bacteria strains were measured for 9 days. Results: In this study, the bactericidal effects of copper and brass on MRSA, VREFM, and MRPA were verified. The bactericidal effect of stainless steel was much weaker than those of copper and brass. The bactericidal effect was stronger on MRPA than on MRSA or VREFM. Conclusion: To prevent cross infection of multidrug resistant bacteria in hospitals, further studies of longer duration are needed for testing of copper materials on objects such as door knobs, faucets, and bed rails.

• Biomedical Science Letters
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• v.21 no.2
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• pp.84-91
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• 2015

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 $\beta$-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.