• Journal of fish pathology
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• v.37 no.1
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• pp.133-138
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• 2024

This study is a report on combinational effects between four sesquiterpene lactones (SLs) from bay laurel (Laurus nobilis) leaves, and oxytetracycline (OTC) or amoxicillin (AMX) against four fish pathogenic bacteria such as Vibrio anguillarum, V. harveyi, Edwardsiella tarda, and Streptococcus iniae. Individually, four SLs exerted little antibacterial activity against fish pathogenic bacteria. However, when combined with OTC or AMX, they showed synergistic interaction against pathogenic bacteria. Especailly, zaluzanin C (1) reduced the MIC of OTC (or AMX) eight-fold. Our results showed that combinations of SLs with antibiotics (ABTs) are more effective than ABTs alone to control pathogenic bacteria. The highest synergistic effect was observed when zaluzanin C (1) was combined with OTC or AMX against V. harvey or S. iniae, displaying significant reductions of MICs up to 8-fold (0.125 to 0.015 ㎍/mL and 0.0078 to 0.0009 ㎍/mL). In addition, zaluzanin C (1) improved the antibiotic potency of OTC against OTC resistant V. harveyi (250 ㎍/mL to 62.5 ㎍/mL). Synergism between ABTs and phytochemical such as SLs could be a therapeutically helpful concept to improve the efficacy of ABTs and prevent antibiotic resistance. These results suggest that SLs can be used as an alternative to reduce antibiotic resistance in aquaculture.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.3
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• pp.166-172
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• 2006

Metallo-${\beta}$-lactamase (MBL) can hydrolyze all ${\beta}$-lactams except monobactams and frequently coexists with various antibiotic resistance genes such as aminoglycoside resistance, sulfonamide resistance gene, etc. Therefore, the effective antibiotics against infections by these bacteria are markedly limited or can't even be found. We tried to search in-vitro antimicrobial combinations with synergistic effects for a VIM-2 type MBL producing Pseudomonas aeruginosa, isolated from clinical specimen. On the selection of antibiotic combinations with synergistic effects, we performed a one disk synergy test, modified Pestel's method, in agar without aztreonam (AZT). The bacteriostatic synergistic effects of this tests were scored as $S_1$ (by susceptibility pattern in agar without antibiotics), $S_2$ (by the change of susceptibility in agar with or without antibiotics) and $S_3$ ($S_1$ + $S_2$) and was classified into weak (1 point), moderate (2 points) and strong (3 points) by $S_3$ score. Subsequently, we carried out the time-killing curve for the antibiotic combinations with the strong synergistic bacteriostatic effect. One VIM-2 type MBL producing P. aeruginosa confirmed by the PCR showed all resistance against all ${\beta}$-lactams except AZT, aminoglycoside and ciprofloxacin. In the one disk synergy test, this isolate showed a strong bacteriostatic synergistic effect for the antibiotic combination of AZT and piperacillin-tazobactam (PIP-TZP) or AZT and amikacin (AN). On the time-killing curve after six hours of incubation, the colony forming units (CFUs/mL) of this bacteria in the medium broth with both combination antibiotics were decreased to 1/18.7, 1/17.1 of the least CFUs of each single antibiotics. The triple antibiotic combination therapy including AZT, PIP-TZP and AN was shown to be significantly synergistic after 8 hrs of exposure. In a VIM-2 MBL producing P. aeruginosa with susceptibility for AZT, the triple antibiotic combination therapy including AZT, PIP-TZP and AN may be considered as an alternative antibiotics modality against the infection by some MBL type. But the antimicrobial combination therapy for many more MBL producing isolates is essential to know as soon as possible for the selection of effective treatment against the infection by this bacteria.

• Food Science and Biotechnology
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• v.17 no.2
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• pp.402-407
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• 2008

The synergistic antimicrobial effect of Achyranthes japonica Nakai (AJN) and Bifidobacterium extracellular factors against Clostridium difficile were measured using a turbidity method. Each broth supernatant of Bifidobacterium infantis ($68.8{\pm}0.02%$) and Bifidobacterium adolescentis ($33.2{\pm}0.2%$) obtained by adding ethyl acetate soluble fractionate from A. japonica Nakai ethanolic extracts (AJNEA, 100 ppm, no inhibition) showed high synergistic antimicrobial activity against C. difficile. In addition, the antimicrobial activity in a laboratory medium and yogurt products against C. difficile were evaluated. In yogurt prepared with a starter 5 (Lactobacillus acidophilus: Streptococcus thermophilus: B. adolescentis =1 : 1 : 1) and a starter 4 (L. acidophilus: S. thermophilus: B. infantis=1 : 1 : 1) and 0.5% AJNEA powder, high antimicrobial effects were recorded that measured 79.0 and 65.2%, respectively. The results indicated the potential of AJN extract for use as an antimicrobial agent. In addition, the efficiency of the antimicrobial activity of the extracts was further improved in combination with lactic acid bacteria, which suggests that they have the potential to be used as a highly effective antibiotic-tolerant microorganism prevention system. Such a strategy can be used for alternative drugs or functional food additives for treatment of antibiotic-associated diarrhea.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.366-372
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• 2020

Since, side effects of antibiotics are frequently emphasized these days, their use is gradually diminishing, and alternative drugs are being developed. We have sought to reintroduce them as raw materials for human health as conventional 'weapons' that have been retired after their historical duties. In this study, we investigated the anti-inflammatory effects of lincomycin (LIN), on lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. Our findings show that LIN potently inhibited production of LPS-induced proinflammatory mediators, such as nitric oxide (NO) and prostaglandin E₂ (PGE₂), without cytotoxicity. Consistent with these findings, LIN strongly decreased protein expression levels of inducible NO synthase (iNOS) and cyclooxygenase (COX-2). Furthermore, LIN reduced pro-inflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1β. To further elucidate the mechanisms of these inhibitory effects of LIN, we studied LPS-induced IκB-α degradation, and mitogen-activated protein kinase (MAPK) phosphorylation. LIN suppressed downregulation of inhibitory κB (IκB-α) degradation, and the phosphorylation of the c-Jun N-terminal kinase (JNK) pathway. Based on these results, we suggest that LIN may be considered a potential candidate as an anti-inflammatory cosmetic or a medicine for human health.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.6
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• pp.886-893
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• 2012

Methicillin-Resistant Staphylococcus aureus (MRSA) is a cephalosporin and beta-lactam antibiotic-resistant strain. In most cases, MRSA is spread from infected patients and infection rates are growing increasingly. Furthermore, increased resistance to antibiotics is causing serious problems in the world. Staphylococcus aureus is responsible for both nosocomial and community-based infections that range from relatively minor skin and soft tissue infections to life-threatening systemic infections. Therefore, there is a need to develop alternative antimicrobial drugs for the treatment of infectious diseases. In this study, we investigated antimicrobial activity of oriental medicine prescription against MRSA. The minimum inhibitory concentration (MIC) of Sohamhyung-tang water extract against S. aureus strains ranged from 500 to 2,000 ${\mu}g/mL$, so we have it confirmed that a strong antibacterial effect. Also, the combinations of Sohamhyung-tang water extract and conventional antibiotics exhibited improved inhibition of MRSA with synergy effect. We suggest that Sohamhyung-tang water extract against MRSA have antibacterial activity, it has potential as alternatives to antibiotic agent. We suggest that the Sohamhyung-tang water extract lead the treatment of bacterial infection to solve the resistance and remaining side-effect problems that are the major weak points of traditional antibiotics.

• Fisheries and Aquatic Sciences
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• v.16 no.2
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• pp.79-84
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• 2013

In an effort to discover an alternative antibiotic for treating infections with methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas sp. UJ-6, a marine bacterium that exhibited antibacterial activity against MRSA, was isolated. The culture broth and its ethyl acetate extract exhibited bactericidal activity against MRSA. The extract also exhibited antibacterial activity against gram-negative bacteria, which were not susceptible to vancomycin. The treatment of MRSA with the extract resulted in abnormal cell lysis. The extract retained >95% of its anti-MRSA activity after heat treatment for 15 min at $121^{\circ}C$. Thus, although most antibiotics are unstable under conditions of thermal stress, Pseudomonas sp. UJ-6 produces a heat-stable anti-MRSA substance. The results of this study strongly suggest that Pseudomonas sp. UJ-6 can be used to develop a novel, heat-stable, broad-spectrum antibiotic for the treatment of MRSA infections.

• Food Science of Animal Resources
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• v.36 no.5
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• pp.567-576
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• 2016

Poultry industry has always been a dynamic and integral part of national economies in many countries. Economic losses incur especially in large-scale rearing facilities, often attributed to the deterioration of environmental conditions, poultry exposure to stressors and development of diseases. While antibiotics have been commonly used for prophylactic purposes and as growth stimulants, extensive documentation of antimicrobial resistance among pathogenic bacteria due to indiscriminate utilization of antibiotic in the industry has led to public and governmental outcries. Elimination of antibiotics from poultry production has thus encouraged intensive search for alternatives. In this review, we discuss the immense potential of probiotics to fill the gap as alternative growth promoters and evidences of beneficial effects of probiotic application in poultry production.

• Restorative Dentistry and Endodontics
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• v.43 no.3
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• pp.31.1-31.7
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• 2018

Despite considerable focus on the regenerative endodontic treatment of immature teeth with necrotic infected pulps and apical periodontitis, little data exist with regard to its possible implementation in necrotic permanent teeth with complete apical and radicular development. The present report describes the procedures and outcome of a regenerative endodontic treatment approach in 2 previously-traumatized incisors with closed apex with apical periodontitis. A 2-visit treatment procedure was employed. At initial visit, the root canals were copiously irrigated, followed by placement of a triple antibiotic paste containing ciprofloxacin, metronidazole, and clindamycin into the root canals. After 4 weeks, the antibiotic paste was removed, and apical bleeding was initiated with size 10 hand files beyond the apices. The root canals were coronally sealed with mineral trioxide aggregate, and the access cavities were restored with bonded resin composite. At post-operative 60 months, both teeth were remained asymptomatic, with the recall radiographs showing complete resolution of apical radiolucency and reestablishment of periradicular tissues. In both teeth, the dimensions of root space remained unchanged as verified by image analysis. The revitalization protocol utilizing root canal disinfection and induced apical bleeding in necrotic, closed-apex incisors may offer a clinically acceptable alternative to conventional root canal treatment.

• Korean Journal of Veterinary Service
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• v.32 no.1
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• pp.33-41
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• 2009

In order to develop probiotic strain for pigs, Lactobacillus spp. (527 isolates), Streptococcus spp. (95 isolates) and Bifidobacterium spp. (25 isolates) were isolated from the feces of 35 pigs. These isolates were tested through in vitro experiment such as acid tolerance at pH 2.0 (Lactobacillus spp. and Streptococcus spp.) or pH 3.0 (Bifidobacterium spp.), bile tolerance in MRS broth containing 0.3% (w/v) Oxgall, heat resistance at $70^{\circ}C$ and $80^{\circ}C$ for 5 min, antibiotic resistance, antimicrobial activity against pathogenic bacteria and Caco-2 cell adherence assay. Finally ten most superior strain (5 Lactobacillus spp. strain, 3 Bifidobacterium spp. strain and 2 Streptococcus spp. strain) were selected as potential candidate for probiotic use in pig industry. It could be used as an alternative to antibiotics in feed additives.

• The Korean Journal of Gastroenterology
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• v.72 no.5
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• pp.237-244
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• 2018

While the prevalence of Helicobacter pylori (H. pylori) infection is decreasing in Korea, the incidence of gastric cancer remains high, emphasizing the importance of H. pylori eradication. A new treatment strategy is needed as the eradication rate with standard triple therapy, which is currently the standard first-line regimen for H. pylori infection, has decreased below the optimum level. The major cause of eradication failure is increased antibiotic resistance. Sequential, concurrent, and hybrid therapies that include clarithromycin produce higher eradication rates than conventional standard triple therapy. However, the effectiveness of these treatments is limited in regions where the resistance rate to various antibiotics is high. Bismuth quadruple therapy is another alternative therapy, but again the eradication rate is not sufficiently high. Tailored therapy based on individual characteristics, including antibiotic susceptibility, may be ideal, but there are several limitations for clinical application and further research is needed. New potassium-competitive acid blocker-based therapies could emerge as effective alternatives in the near future. A consensus is needed to establish a strategy for applying new eradication therapies in Korea.