Inhibition of Quorum Sensing Regulated Virulence Factors and Biofilm Formation by Eucalyptus globulus against Multidrug-Resistant Pseudomonas aeruginosa

Pankaj Kumar Sagar,Poonam Sharma,Rambir Singh 대한약침학회 2022 Journal of pharmacopuncture Vol.25 No.1

Objectives: The quorum-sensing–inhibitory and anti-biofilm activities of the methanol extract of E. globulus leaves were determined against clinically isolated multidrug-resistant Pseudomonas aeruginosa. Methods: The preliminary anti-quorum–sensing (AQS) activity of eucalyptus was investigated against a biosensor strain Chromobacterium violaceum ATCC 12472 (CV12472) by using the agar well diffusion method. The effect of sub-minimum inhibitory concentrations (sub-MICs) of the methanol extract of eucalyptus on different quorum-sensing–regulated virulence factors, such as swarming motility, pyocyanin pigment, exopolysaccharide (EPS), and biofilm formation, against clinical isolates (CIs 2, 3, and 4) and reference PA01 of Pseudomonas aeruginosa were determined using the swarm diameter (mm)-measurement method, chloroform extraction method, phenol (5%)-sulphuric acid (concentrated) method, and the microtiter plate assay respectively, and the inhibition (%) in formation were calculated. Results: The preliminary AQS activity (violacein pigment inhibition) of eucalyptus was confirmed against Chromobacterium violaceum ATCC 12472 (CV12472). The eucalyptus extract also showed concentration-dependent inhibition (%) of swarming motility, pyocyanin pigment, EPS, and biofilm formation in different CIs and PA01 of P. aeruginosa. Conclusion: Our results revealed the effectiveness of the E. globulus extract for the regulation of quorum-sensing–dependent virulence factors and biofilm formation at a reduced dose (sub-MICs) and suggest that E. globulus may be a therapeutic agent for curing and controlling bacterial infection and thereby reducing the possibility of resistance development in pathogenic strains.

식용 식물추출물의 구강 세균에 대한 항균 활성

이지혜 ( Jihye Lee ),김연아 ( Yeona Kim ),김동청 ( Dong Chung Kim ),채희정 ( Hee Jeong Chae ) 한국응용생명화학회 2020 Journal of Applied Biological Chemistry (J. Appl. Vol.63 No.1

Thirty-five edible plants were tested against oral bacteria (Streptococcus mutans, Lactobacillus casei, Staphylococcus epidermidis, Klebsiella pneumonia). The edible plants were extracted using 70% ethanol as a solvent. Among the thirty-five edible plants, hibiscus (Hibiscus sabdariffa) extract was selected as an effective antibacterial source because it showed the lowest minimum inhibitory concentration. The antimicrobial substances of hibiscus extract were very stable at acidic condition and at wide range of temperature 4-75℃. The total polyphenol and flavonoid contents of hibiscus extract were 130.5 and 25.7 mg/g, respectively. Also hibiscus extract showed a high degree of antioxidant activity.

소목(Caesalpinia sappan L.) 추출물의 피부 상재균에 대한 항균 활성

황미경 ( Mi Kyung Hwang ),이용현 ( Yong Hyun Lee ),김동청 ( Dong Chung Kim ) 한국응용생명화학회 2021 Journal of Applied Biological Chemistry (J. Appl. Vol.64 No.1

Antimicrobial activity of an aqueous extract from Caesalpinia sappan L. was investigated against skin flora such as Escherichia coli, Staphylococcus aureus, Cutibacterium acnes, and Malassezia furfur. The yield and polyphenol content of the aqueous extract were 14.01±0.81% and 487.5±19.69 μg/mg-extract, respectively. The minimum inhibitory concentration of the aqueous extract against E. coli, S. aureus, C. acnes, and M. furfur was 0.875, 1.750, 1.750, and 1.750 mg/mL, respectively. In disc diffusion test, the aqueous extract of C. sappan L. increased the clear zone in a dose-dependent manner. The aqueous extract inhibited the microbial growth in a concentration-dependent manner.

Characterization of Pasteurella multocida from pneumonic lungs of slaughtered pigs in Korea

Kim, Jong Ho,Kim, Jong Wan,Oh, Sang-Ik,Kim, Chung Hyun,So, ByungJae,Kim, Won-Il,Kim, Ha-Young The Korean Society of Veterinary Service 2018 韓國家畜衛生學會誌 Vol.41 No.3

Pasteurella multocida is an opportunistic organism that plays a significant role in porcine respiratory disease complex (PRDC). In the current study, we provide nationwide information of P. multocida isolates from pneumonic lungs of slaughter pigs by determining their prevalence, subspecies, biovars, capsular types, virulence-associated genes, and minimum inhibitory concentrations. P. multocida was the second most frequently confirmed (19.2%) bacterial pathogen and most of the isolates (88.9%) showed simultaneous infection with other respiratory pathogens, especially Mycoplasma hyopneumoniae (63.3%, P<0.001) and porcine circovirus type 2 (53.3%, P=0.0205). Of 42 isolates investigated, 41 (97.6%) were identified as P. multocida subspecies multocida, and only one isolate was identified as subspecies septica (biovar 5). All the isolates were capsular type A and the most prevalent biovar was biovar 3 (40.5%), followed by biovar 2 (31.0%). Comparing virulence-associated genes and biovars, all biovar 2 isolates exhibited $hgbB^-pfhA^+$ (P<0.001); all biovar 3 (P=0.0002) and biovar 13 (P=0.0063) isolates presented $hgbB^+pfhA^-$. Additionally, all biovar 2 (P=0.0037) isolates and most of biovar 3 (P=0.0265) isolates harbored tadD. P. multocida showed the highest resistance levels to oxytetracycline (73.8%), followed by florfenicol (11.9%). Continuous monitoring is required for surveillance of the antimicrobial resistance and new emerging strains of P. multocida in slaughter lines.

Characterization of Pasteurella multocida from pneumonic lungs of slaughtered pigs in Korea

( Jong Ho Kim ),( Jong Wan Kim ),( Sang-ik Oh ),( Chung Hyun Kim ),( Byungjae So ),( Won-il Kim ),( Ha-young Kim ) 한국동물위생학회 2018 한국동물위생학회지 (KOJVS) Vol.41 No.3

Pasteurella multocida is an opportunistic organism that plays a significant role in porcine respiratory disease complex (PRDC). In the current study, we provide nationwide information of P. multocida isolates from pneumonic lungs of slaughter pigs by determining their prevalence, subspecies, biovars, capsular types, virulence-associated genes, and minimum inhibitory concentrations. P. multocida was the second most frequently confirmed (19.2%) bacterial pathogen and most of the isolates (88.9%) showed simultaneous infection with other respiratory pathogens, especially Mycoplasma hyopneumoniae (63.3%, P<0.001) and porcine circovirus type 2 (53.3%, P=0.0205). Of 42 isolates investigated, 41 (97.6%) were identified as P. multocida subspecies multocida, and only one isolate was identified as subspecies septica (biovar 5). All the isolates were capsular type A and the most prevalent biovar was biovar 3 (40.5%), followed by biovar 2 (31.0%). Comparing virulence-associated genes and biovars, all biovar 2 isolates exhibited hgbB^-pfhA⁺ (P<0.001); all biovar 3 (P=0.0002) and biovar 13 (P=0.0063) isolates presented hgbB⁺pfhA^-. Additionally, all biovar 2 (P=0.0037) isolates and most of biovar 3 (P=0.0265) isolates harbored tadD. P. multocida showed the highest resistance levels to oxytetracycline (73.8%), followed by florfenicol (11.9%). Continuous monitoring is required for surveillance of the antimicrobial resistance and new emerging strains of P. multocida in slaughter lines.

Role of acid responsive genes in the susceptibility of <i>Escherichia coli</i> to ciclopirox

Shin, Jonghoon,Cho, Hyejin,Kim, Suran,Kim, Kwang-sun Elsevier 2018 Biochemical and biophysical research communication Vol.500 No.2

<P><B>Abstract</B></P> <P>Antibiotic resistance poses a huge threat to the effective treatment of bacterial infections. To circumvent the limitations in developing new antibiotics, researchers are attempting to repurpose pre-developed drugs that are known to be safe. Ciclopirox, an off-patent antifungal agent, inhibits the growth of Gram-negative bacteria, and genes involved in galactose metabolism and lipopolysaccharide (LPS) biosynthesis are plausible antibacterial targets for ciclopirox, since their expression levels partially increase susceptibility at restrictive concentrations. In the present study, to identify new target genes involved in the susceptibility of <I>Escherichia coli</I> to ciclopirox, genome-wide mRNA profiling was performed following ciclopirox addition at sublethal concentrations, and glutamate-dependent acid resistance (GDAR) genes were differentially regulated. Additional susceptibility testing, growth analyses and viability assays of GDAR regulatory genes revealed that down-regulation of <I>evgS</I> or <I>hns</I> strongly enhanced susceptibility to ciclopirox. Further microscopy and phenotypic analyses revealed that down-regulation of these genes increased cell size and decreased motility. Our findings could help to maximise the efficacy of ciclopirox against hard-to-treat Gram-negative pathogens.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ciclopirox antibacterial activity was analysed by genome-wide expression profiling. </LI> <LI> Ciclopirox affects expression of glutamate-dependent acid resistance pathway genes. </LI> <LI> Down-regulation of <I>hns</I> transcription likely increases ciclopirox activity. </LI> <LI> Susceptibility to ciclopirox accompanies increased cell size and decreased motility. </LI> <LI> The findings identify probable pathways for ciclopirox action against <I>E. coli</I>. </LI> </UL> </P>

Recent Developments of Chip-based Phenotypic Antibiotic Susceptibility Testing

김승규,Fahim Masum,전성윤 한국바이오칩학회 2019 BioChip Journal Vol.13 No.1

Antibiotic susceptibility testing (AST), the screening of effective types and dosages of antibiotics, has become significantly important in the antimicrobial- resistance era over the last few decades. In order to overcome the limitations of conventional AST methods, several recent studies have developed AST platforms which exhibit the advantages of microfluidics. They demonstrated the performance of the platforms by determining effective antimicrobials for bacterial strains and their minimum inhibitory concentrations within hours. In this review, we cover recent developments of on-chip approaches for measurements of bacterial growth as well as for dilutions of antibiotic concentrations. We also discuss Point-of-Care AST devices that employ inexpensive materials and simple working principles to operate screenings near the site of care, which can potentially bring current laboratory- limited assays to clinical standards. All thing considered, emerging microfluidic AST devices have the potential to be decent alternatives to commonplace macro-scale AST methods.

Comparison of Minimum Inhibitory Concentration Distributions between Delpazolid and Linezolid Against Mycobacterium Avium, Mycobacterium Intracellulare in Korea

( Hyeonji Kim ),( Jeong Seong Yang ),( Minji Kang ),( Seung Heon Lee ),( Dong Yeon Shin ),( Young Lag Cho ),( Nakwon Kwak ),( Jae-joon Yim ),( Jake Whang ) 대한결핵 및 호흡기학회 2020 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.128 No.0

Background n South Korea, the major causative agents of nontuberculous mycobacteria (NTM) pulmonary disease (PD) are Mycobacterium avium complex (MAC), composed of M. avium and M. intracellular. Linezolid is a first-line drug for drug-resistant tuberculosis, but it is only used for refractory MAC or M. abscessus lung disease. Since, linezolid has a high minimum inhibitory concentration (MIC) distribution of MAC, with an ECOFF value of 64 ug/ml. Another problem is that linezolid has serious side effects in long-term requiring NTM treatment. Delpazolid, a same oxazolidinone family, showed slightly better MIC distributions for MAC, but the most notable difference is that the side effects are remarkably low. These advantages were sufficiently confirmed through animal experiments and phase 1 clinical trials. However, comparing the antimicrobial activity of linezolid and delpazolid in clinical strains of M. avium, M. intracellulare was not reported yet. Methods The MIC of delpazolid and linezolid were compared with the domestic clinical strains M. avium (n=101) and M. intracellulare (n=104) by broth microdilution Method. Results In the case of M. avium, the separation rate of resistant strains of delpazolid was 45 %, which was 3 % lower than that of linezolid applying the same resistance reference concentration as 16 ug/ml. M. intracellulare was similar with linezolid resistance rate 82.69 % (n = 86) and delpazolid resistance rate 83.65 % (n = 87). Conclusions In this study, we compared the MIC of two antibiotics against clinical isolate. In the M. avium strain, the resistance ratio of linezolid was 3 % higher than that of delpazolid resistance. M. intracellulare resistance rates were similar for linezolid and delpazolid. Since there are significantly fewer side effects, it is expected that delpazolid can replace linezolid in refractory MAC or M. abscessus PD treatment which requiring long-term antibiotic administration.

농산물에서 분리한 무름병균의 항생제 최소 억제농도 조사

김다운(Dawoon Kim),김나예슬(Nayeseul Kim),김채린(Chaerin Kim),정명인(Myung-In Jeong),오광교(Kwang Kyo Oh),김보은(Bo-Eun Kim),류재기(Jae-Gee Ryu),정지은(Jieun Jung),지삼녀(Samnyu Jee),류경열(Kyoung-Yul Ryu) 한국농약과학회 2021 농약과학회지 Vol.25 No.4

Pectobacterium carotovorum subsp. carotovorum(Pcc) causes the destructive bacterial soft rot on a wide range of crops in Korea. This study was conducted to elucidate the characteristics and antimicrobial response of soft rot isolates collected from chinese cabbage, radish and potato cultivation areas. The pathogenicity on potato, carrot, chinese cabbage and lettuce were evaluated according to severity of bacterial soft rot at different temperature after inoculation. Isolates collected from winter chinese cabbage showed strong pathogenicity in four tested crop and produced the similar symptom in wide range temperature from 10 to 30oC. The minimum inhibitory concentration (MIC) of streptomycin and tetracycline were investigated for 76 soft rot isolates obtained from different cultivation regions. The soft rot bacteria showed the various response against two agricultural antibiotics, and four isolates were not inhibited at over 100 μg/mL concentration of streptomycin. Recently isolated soft rot bacteria showed over the two times high minimum inhibitory concentration of streptomycin and tetracycline compared to them isolated 20 years ago. Also, the soft rot bacteria were tested minimum inhibitory concentration of 16 antibiotics using sensititre instrument system and showed minimum inhibitory concentration against nalidixic acid ranged from 2 to 128 μg/mL. These results provide the fundamental information on change of antibiotics response associated with soft rot bacteria and the further studies are necessary for management of agricultural antibiotics resistance.

Evaluation of the Phenolic Content, Antioxidant and Antimicrobial Activities of Oil and Non-Oil Extracts of Citrus sinensis (L.) Osbeck Seeds

Ehigbai I. Oikeh,Merit Ayevbuomwan,Francis Irabor,Aiemere O. Oikeh,Faith E. Oviasogie,Ehimwenma S. Omoregie 한국식품영양과학회 2020 Preventive Nutrition and Food Science Vol.25 No.3

The seeds of Citrus sinensis (L.) Osbeck (sweet orange) are waste products usually discarded. They may however contain phytochemicals that have potent bioactivities. In this study, the phenolic content, and antioxidant and antimicrobial activities of oil and non-oil (solid) extracts of C. sinensis seeds were evaluated using standard protocols. The seed oil contained significantly (P>0.05) higher contents of total phenol and total flavonoid when compared to the solid extract. However, the non-oil extract contained significantly (P<0.05) higher tannin contents than the seed oil. Ferric reducing antioxidant potential was not significantly different between both extracts. The antimicrobial activities of both extracts revealed that the seed oil possesses better antibacterial activities compared to the non-oil extract. The antifungal test revealed that the seed oil significantly inhibited the growth of Candida albicans (20 ㎜ zone of inhibition at a concentration of 200 ㎍/mL), however, it did not inhibit the growth of Aspergillus niger and Penicillum sp. The minimum inhibitory concentration values against the bacterial and fungal strains were similar for both extracts in the range of 50∼100 ㎍/mL. Minimum bactericidal concentration and minimum fungicidal concentration values ranged from 100∼200 ㎍/mL for both extracts. The results in this study indicate that C. sinensis seed oil and non-oil extracts possess antioxidant, and antibacterial and antifungal properties that may be differentially exploited in the development of antimicrobial agents.