• Natural Product Sciences
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• v.23 no.4
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• pp.286-290
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• 2017

Multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa are highly dangerous nosocomial pathogens, cause the symptoms of skin infections, pressure sores, sepsis, blood stream and wound infections. Unfortunately, these pathogens are immune to the most common antibiotics, such as, carbapenem, aminoglycoside and fluoroquinolone. Therefore, it is imperative that new and effective antibiotics be developed. In the present study, the antimicrobial effects of Aloe vera MAP (modified Aloe polysaccharide) on Staphylococcus aureus and Bacillus subtilis, Escherichia coli and Enterobacter aerogenes, and clinical Pseudomonas aeruginosa and clinical Acinetobacter baumannii were comprehensibly investigated. Prior to the growth inhibition effect measurement and antibiotic disc diffusion assay on gram-positive and gram-negative bacteria and selected multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii, antimicrobial resistance screening was performed for the multidrug-resistant bacteria obtained from clinical isolates. The results for showed the Aloe vera MAP had a concentration-dependent effect on all of examined bacteria, particularly on Pseudomonas aeruginosa. Anti-inflammatory and anti-oxidant experiments were also performed dose dependently effects to confirm the beneficial physiological effects of Aloe vera MAP.

• Natural Product Sciences
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• v.24 no.4
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• pp.225-228
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• 2018

By activity-guided fractionation, gliotoxin was isolated as an antibacterial metabolite of the fungus Penicillium decumbens which was derived from the jellyfish Nemopilema nomurai. Gliotoxin was further evaluated for antibacterial activity against several piscine and human MDR (multidrug resistance) pathogens. Gliotoxin showed significant antibacterial activity against Gram-positive piscine pathogens such as Streptococcus iniae FP5228, Streptococcus iniae FP3187, Streptococcus parauberis FP3287, Streptococcus parauberis SPOF3K, S. parauberis KSP28, and Lactococcus garvieae FP5245. Gliotoxin showed strong activity especially against S. parauberis SPOF3K and S. iniae FP5228, which are resistant to oxytetracycline. It is noteworthy that gliotoxin effectively suppressed streptococci which are the major pathogens for piscine infection and mortality in aquaculture industry. Gliotoxin also showed strong antibacterial activity against multidrug- resistant human pathogens (MDR) including Enterococcus faecium 5270 and MRSA (methicillin-resistant Staphylococcus aureus) 3089.

• Proceedings of the Microbiological Society of Korea Conference
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• 2009.05a
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• pp.68-69
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• 2009

• Korean Journal of Clinical Laboratory Science
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• v.50 no.4
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• pp.431-437
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• 2018

Acinetobacter baumannii is categorized as a red alert pathogen that is increasingly associated with a high mortality rate in infected patients because of its resistance to extensive antibiotics. This study evaluated the antibacterial activities of some essential oils (tee tree, rosemary, and lavender oils) against 18 clinical isolates of multidrug-resistant A. baumannii (MRAB). The carbapenemase screening Hodge test showed that all 20 strains of A. baumannii were resistant to imipenem. The identification of multidrug-resistant microbes was carried out using the VITEK system. The antimicrobial activity of essential oils was tested by a disk diffusion method against MRAB. In the disk diffusion method, tea tree showed the largest increase in inhibition size compared to lavender oil, and rosemary had no antibacterial effect. These results proved the antimicrobial effect of multidrug resistance A. baumannii. Tee tree oil would be a useful alternative natural product for the treatment and prevention of most common human pathogens and MRAB infections. This is expected to be used as an antimicrobial agent, such as hand disinfectant using natural essential oil in the future.

• Microbiology and Biotechnology Letters
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• v.42 no.2
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• pp.152-161
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• 2014

The in vitro antimicrobial potential of the unexplored Moringa oleifera seed coat (SC) was evaluated against some Gram-positive and Gram-negative bacteria and yeast pathogens. Antimicrobial studies with various solvent extracts indicated ethyl acetate to be the best extractant, which was used for the rest of the antimicrobial studies as it tested neither toxic nor mutagenic. Gram-positive bacteria including a methicillin resistant Staphylococcus aureus (MRSA) strain were more susceptible with a minimum inhibitory concentration (MIC) range of 0.03-0.04 mg/ml. The antimicrobial pharmacodynamics of the extract exhibited both concentration-dependent and time-dependent killing. Most of the test organisms exhibited a short post antibiotic effect (PAE) except Enterococcus faecalis, Staphylococcus aureus, and Klebsiella pneumoniae 1, which exhibited longer PAEs. Amongst the major phytoconstituents established, flavonoids, diterpenes, triterpenes and cardiac glycosides exhibited inhibitory properties against most of the test organisms. The identified active phytochemicals of the M. oleifera seed coat exhibited antimicrobial potential against a wide range of medically important pathogens including the multidrug-resistant bugs. Hence, the M. oleifera seed coat, which is usually regarded as an agri-residue, could be a source of potential candidates for the development of drugs or drug leads of broad spectrum that includes multidrug-resistant bugs, which are one of the greatest concerns of the $21^{st}$ century.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.119-124
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• 2011

Currently, people are exposed to many harmful diseases. Therefore, there are many schemes, such as automation of productive facilities, development of information and communication technology, enhanced the quality of human life and wealth. However, these processes lead to weakened immune system. Thus, people are more vulnerable to infections from pathogens and environmental stress. Misuse and abuse of drugs resulted in the rapid emergence of multidrug-resistant microbes and tumors, therefore, to find new antibiotics are urgently needed. One of them is a peptide-antibiotic, that is not or less occurred a drug-resistance, comparing to conventional drugs. Peptides with various antibiotic activities have been identified from life organisms. The present review provides an overview of activities and application of peptide antibiotics.

• Journal of Oral Medicine and Pain
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• v.47 no.1
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• pp.52-61
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• 2022

Purpose: Most cases of oral and maxillofacial infections are usually easily treated by proper diagnosis, elimination of causative factors, and antibiotic therapy. However, the emergence and the increase of multidrug-resistant bacteria make treatment challenging. "ESKAPE" pathogens are the most common opportunistic organisms in nosocomial infections and have resistant to commonly used antibiotics. There are many medical reviews of ESKAPE pathogens, but few in dentistry. This study focuses on oral and maxillofacial infection especially with ESKAPE pathogens. The purpose of this study is to prepare feasible data about tracing and treatment of infection related to pathogens that may be beneficial to clinicians. Methods: A total of 154 patients with oral and maxillofacial infections were reviewed by analyzing retrospectively hospitalized data in the Department of Oral and Maxillofacial surgery, Chosun University Hospital, Korea, past 5 years from January 2014 to December 2018. Based on the medical records and microbiological tests, the results were divided into two groups: infections with ESKAPE pathogens and other bacteria. Results: A total of 22 species were isolated from 154 patients. The proportion of ESKAPE pathogens among all bacterial isolates collected from infected patients was 39.6%. Causative factors, especially in post-operative infection, showed a statistically significant correlation to ESKAPE infections (29 cases). And average of treatment period in ESKAPE group was longer than non-ESKAPE groups. Overall, Klebsiella pneumoniae (60.7%) was the most frequently isolated ESKAPE pathogen. And high antibiotic resistance rates had been detected in the ESKAPE during the five-year period. Conclusions: Infections with ESKAPE pathogens are now a problem that can no longer be overlooked in Dentistry. Based on results of this study, ESKAPE pathogens were highly associated with post-operative or opportunistic infections. Clinicians should be careful about these antibiotic resistant pathogens and use appropriate antibiotics to patients while having dental treatments.

• Acute and Critical Care
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• v.33 no.4
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• pp.238-245
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• 2018

Background: Infection by multidrug-resistant (MDR) pathogens leads to poor patient outcomes in intensive care units (ICUs). Contact precautions are necessary to reduce the transmission of MDR pathogens. However, the importance of the surrounding environment is not well known. We studied the effects of ICU relocation on MDR respiratory pathogen detection rates and patient outcomes. Methods: Patients admitted to the ICU before and after the relocation were retrospectively analyzed. Baseline patient characteristics, types of respiratory pathogens detected, antibiotics used, and patient outcomes were measured. Results: A total of 463 adult patients admitted to the ICU, 4 months before and after the relocation, were included. Of them, 234 were admitted to the ICU before the relocation and 229 afterward. Baseline characteristics, including age, sex, and underlying comorbidities, did not differ between the two groups. After the relocation, the incidence rate of MDR respiratory pathogen detection decreased from 90.0 to 68.8 cases per 1,000 patient-days, but that difference was statistically insignificant. The use of colistin was significantly reduced from 53.5 days (95% confidence interval [CI], 20.3 to 86.7 days) to 18.7 days (95% CI, 5.6 to 31.7 days). Furthermore, the duration of hospital stay was significantly reduced from a median of 29 days (interquartile range [IQR], 14 to 50 days) to 21 days (IQR, 11 to 39 days). Conclusions: Incidence rates of MDR respiratory pathogen detection were not significantly different before and after ICU relocation. However, ICU relocation could be helpful in reducing the use of antibiotics against MDR pathogens and improving patient outcomes.

• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.61-74
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• 2023

The global increase in multidrug-resistant (MDR) bacteria has inspired researchers to develop new strategies to overcome this problem. In this study, 23 morphologically different, soil-isolated actinomycete cultures were screened for their antibacterial ability against MDR isolates of ESKAPE pathogens. Among them, isolate BOGE18 exhibited a broad antibacterial spectrum, so it was selected and identified based on cultural, morphological, physiological, and biochemical characteristics. Chemotaxonomic analysis was also performed together with nucleotide sequencing of the 16S rRNA gene, which showed this strain to have identity with Streptomyces lienomycini. The ethyl acetate extract of the cell-free filtrate (CFF) of strain BOGE18 was evaluated for its antibacterial spectrum, and the minimum inhibitory concentration (MIC) ranged from 62.5 to 250 ㎍/ml. The recorded results from the in vitro anti-biofilm microtiter assay and confocal laser scanning microscopy (CLSM) of sub-MIC concentrations revealed a significant reduction in biofilm formation in a concentration-dependent manner. The extract also displayed significant scavenging activity, reaching 91.61 ± 4.1% and 85.06 ± 3.14% of 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), respectively. A promising cytotoxic ability against breast (MCF-7) and hepatocellular (HePG2) cancer cell lines was obtained from the extract with IC₅₀ values of 47.15 ± 13.10 and 122.69 ± 9.12 ㎍/ml, respectively. Moreover, based on gas chromatography-mass spectrometry (GC-MS) analysis, nine known compounds were detected in the BOGE18 extract, suggesting their contribution to the multitude of biological activities recorded in this study. Overall, Streptomyces lienomycini BOGE18-derived extract is a good candidate for use in a natural combating strategy to prevent bacterial infection, especially by MDR pathogens.

• 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.