Antimicrobial Activity of Tripitsajuk Crude Etract against Escherichia coli and Pseudomonas aeruginosa
Article Sidebar
Views | PDF/EPUB Downloads:
177
/ 122
/ 39
Main Article Content
Abstract
The escalating prevalence of antibiotic-resistant gram-negative bacteria necessitates urgent exploration of alternative therapeutic approaches. Tripitsajuk (TPJ), a traditional Thai medicinal formulation containing Myristica fragrans (nutmeg), Oenanthe javanica (water dropwort), and Syzygium aromaticum (clove), has shown promising antimicrobial properties against gram-positive organisms, yet its efficacy against gram-negative pathogens remains uninvestigated. This study evaluated the antimicrobial potential of Tripitsajuk crude extracts against clinically significant gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa. Plant materials were extracted using two solvent systems: 40% ethanol (TPJHE40) and absolute ethanol (TPJE) through seven-day maceration. Antimicrobial assessment employed the agar well diffusion technique with extract concentrations ranging from 12.5 to 100 mg/mL. Gentamicin served as the positive control, while 10% dimethyl sulfoxide functioned as the negative control. Statistical analysis was performed using one-way analysis of variance followed by Tukey's post-hoc test with significance established at P < 0.05. TPJE extraction yielded 11.228% compared to 9.903% for TPJHE40. Only TPJE exhibited antimicrobial activity against the two tested organisms. Against E. coli, TPJE showed concentration-dependent inhibition from 12.5 mg/mL (12.00±0.00 mm) to 100 mg/mL (17.11±0.11 mm). P. aeruginosa demonstrated greater resistance, responding only to 100 mg/mL (11.44±0.29 mm). TPJHE40 extract failed to produce measurable inhibition zones at any concentration tested. The absolute ethanol extract of Tripitsajuk demonstrated significant antimicrobial efficacy against gram-negative bacteria at high concentrations, with E. coli displaying higher susceptibility compared to P. aeruginosa. These findings establish Tripitsajuk as a promising candidate for development into adjunctive or alternative antimicrobial therapeutics, particularly for managing drug-resistant gram-negative bacterial infections.
Keywords:
Downloads
Article Details
Section
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
How to Cite
References
1.Sati H, Carrara E, Savoldi A, Hansen P, Garlasco J, Campagnaro E, Boccia S, Castillo-Polo JA, Magrini E, Garcia-Vello P, Wool E, Gigante V, Duffy E, Cassini A, Huttner B, Pardo PR, Naghavi M, Mirzayev F, Zignol M, Cameron A, Tacconelli E. The WHO Bacterial Priority Pathogens List 2024: a prioritisation study to guide research, development, and public health strategies against antimicrobial resistance. Lancet Infect Dis. 2025; 25(4): 508-519.
2.Fekadu S, Weldegebreal F, Shumie T, Mekonnen GK. A comparative study on nosocomial and community-acquired bacterial urinary tract infections: prevalence, antimicrobial susceptibility pattern, and associated risk factors among symptomatic patients attending Hiwot Fana Comprehensive Specialized University Hospital, Eastern Ethiopia. Front Epidemiol. 2025; 5: 1517476.
3.Kuznetsova MV, Nesterova LY, Mihailovskaya VS, Selivanova PA, Kochergina DA, Karipova MO, Valtsifer IV, Averkina AS, Starcic Erjavec M. Nosocomial Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus: Sensitivity to Chlorhexidine-Based Biocides and Prevalence of Efflux Pump Genes. Int J Mol Sci. 2025; 26(1): 355.
4.Antimicrobial Resistance Collaborators. Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis. Lancet. 2022; 399(10325): 629-655.
5.Salam MA, Al-Amin MY, Salam MT, Pawar JS, Akhter N, Rabaan AA, Alqumber MAA. Antimicrobial resistance: A growing serious threat for global public health. Healthcare (Basel). 2023; 11(13): 1946.
6.Murray CJ, Ikuta KS, Sharara F, Swetschinski L, Robles Aguilar G, Gray A, Han C, Bisignano C, Rao P, Wool E, Johnson SC, Browne AJ, Chipeta MG, Fell F, Hackett S, Haines-Woodhouse G, Hamadani BH, Kumaran EA, McManigal B, Agarwal R, Akech S, Albertson S, Amuasi J, Andrews J, Aravkin A, Ashley E, Bailey F, Baker S, Basnyat B, Bekker A, Bender R, Berkley JA, Bethou A, Bielicki J, Boonkasidecha S, Bukosia J, Carvalheiro C, Castañeda-Orjuela C, Chansamouth V, Chaurasia S, Chiurchiù S, Chowdhury F, Cook AJ, Cooper B, Cressey TR, Criollo-Mora E, Cunningham M, Darboe S, Day NP, De Luca M, Dokova K, Dramowski A, Dunachie SJ, Eckmanns T, Eibach D, Emami A, Feasey N, Fisher-Pearson N, Forrest K, Garrett D, Gastmeier P, Giref AZ, Greer RC, Gupta V, Haller S, Haselbeck A, Hay SI, Holm M, Hopkins S, Iregui KC, Jacobs J, Jarovsky D, Javanmardi F, Khorana M, Kissoon N, Kobeissi E, Kostyanev T, Krapp F, Krumkamp R, Kumar A, Kyu HH, Lim C, Limmathurotsakul D, Loftus MJ, Lunn M, Ma J, Mturi N, Munera-Huertas T, Musicha P, Musila LA, Mussi-Pinhata MM, Nakamura T, Nanavati R, Nangia S, Newton P, Ngoun C, Novotney A, Nwakanma D, Obiero CW, Olivas-Martinez A, Olliaro P, Ooko E, Ortiz-Brizuela E, Peleg AY, Perrone C, Plakkal N, Ponce-de-Leon A, Raad M, Ramdin T, Riddell A, Roberts T, Robotham JV, Roca A, Rudd KE, Russell N, Schnall J, Scott JA, Shivamallappa M, Sifuentes-Osornio J, Steenkeste N, Stewardson AJ, Stoeva T, Tasak N, Thaiprakong A, Thwaites G, Turner C, Turner P, van Doorn HR, Velaphi S, Vongpradith A, Vu H, Walsh T, Waner S, Wangrangsimakul T, Wozniak T, Zheng P, Sartorius B, Lopez AD, Stergachis A, Moore C, Dolecek C, Naghavi M. Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis. Lancet. 2022; 399(10325): 629-655.
7.Newman DJ, Cragg GM. Natural products as sources of new drugs over the nearly four decades from 01/1981 to 09/2019. J Nat Prod. 2020; 83(3): 770-803.
8.Atanasov AG, Zotchev SB, Dirsch VM, Supuran CT. Natural products in drug discovery: advances and opportunities. Nat Rev Drug Discov. 2021; 20(3): 200-216.
9.Pang Z, Zhu Q. Traditional Chinese Medicine is an Alternative Therapeutic Option for Treatment of Pseudomonas aeruginosa Infections. Front Pharmacol. 2021; 12: 737252.
10.Li J, Chen Y, Wang X, Zhang H, Liu M, Zhao L, Wu P. Effects of Traditional Chinese Medicine and its Active Ingredients on Drug-Resistant Bacteria. Front Pharmacol. 2022; 13: 837907.
11.Techaoei S. Time-kill kinetics and antimicrobial activities of Thai medical plant extracts against fish pathogenic bacteria. J Adv Pharm Technol Res. 2022; 13(1): 25-29.
12.Saeloh D, Visutthi M. Efficacy of Thai plant extracts for antibacterial and anti-biofilm activities against pathogenic bacteria. Antibiotics (Basel). 2021; 10(12): 1470.
13.Al-Qahtani WH, Dinakarkumar Y, Arokiyaraj S, Saravanakumar V, Rajabathar A, Arjun K, Alshehri MA, Ghilan AKM, Almutairi MH, Alghamdi AAA. Phyto-chemical and biological activity of Myristica fragrans, an ayurvedic medicinal plant in Southern India and its ingredient analysis. Saudi J Biol Sci. 2022; 29(5): 3815-3821.
14.Al-Farsi MA, Al-Amri IS, Al-Hadhrami A, Al-Turki S. Minimum inhibitory concentration of plant extracts with proven antimicrobial activity against pathogenic bacteria. Saudi J Biol Sci. 2018; 25(6): 1509-1515.
15.Jang HN, Lee SH, Kim JY, Kim GC. Oenanthe javanica ethanolic extract alleviates inflammation and modifies gut microbiota in mice with DSS-induced colitis. Antioxidants (Basel). 2022; 11(12): 2429.
16.Maggini V, Semenzato G, Gallo E, Nunziata A, Fani R, Firenzuoli F. Antimicrobial activity of Syzygium aromaticum essential oil in human health treatment. Molecules. 2024; 29(5): 999.
17.Teles AM, Rosa T, Mouchrek AN, Abreu-Silva AL, Calabrese KS, Almeida-Souza F. GC-MS characterization of antibacterial, antioxidant, and antitrypanosomal activity of Syzygium aromaticum essential oil and eugenol. Evid Based Complement Alternat Med. 2021; 6663255.
18.Boughroud H, Chgari O, Wahnou H, Amrani AE, Faqer OE, Amarir F, Mtairag EM, Rais S, Bourjilat F. Assessing Syzygium aromaticum: from chemical profiling to antioxidant, antistaphylococcal, and biocompatibility attributes. Chem Biodivers. 2025; 22(4): e202402605.
19.Thanasai J, Naowaratwattana W, Kanchanarach W, Soncharoen P. Effect of Crude From "Tripitsajuk" Formulary on Growth Inhibition of Staphylococcus aureus and Staphylococcus epidermidis and Antioxidant Activity. Trop J Nat Prod Res. 2025; 9(8): 3845-3853.
20.Alhumaid S, Al Mutair A, Al Alawi Z, Alzahrani AJ, Tobaiqy M, Alresasi AM. Antimicrobial susceptibility of Gram-positive and Gram-negative bacteria: a 5-year retrospective analysis at a multi-hospital healthcare system in Saudi Arabia. Ann Clin Microbiol Antimicrob. 2021; 20(1): 43.
21.Suwandecha T, Daduang J, Kitisak P, Wongwattananukul S, Temsiririrkkul R, Suwanwong Y. Assessment of morphological, anatomical and palynological variation in the medicinal plant Disporopsis longifolia Craib (Asparagaceae) for botanical quality control. Plants (Basel). 2023; 12(2): 259.
22.Phumthum M, Nguanchoo V, Balslev H, Wangpakapattanawong P, Panyadee P, Inta A. Medicinal plants used by rural Thai people to treat non-communicable diseases and related symptoms. Heliyon. 2023; 9(1): e12758.
23.Khonkarn R, Okonogi S, Ampasavate C, Anuchapreeda S. Exploring the therapeutic potential of Thai medicinal plants: in vitro screening and in silico docking of phytoconstituents for novel anti-SARS-CoV-2 agents. Sci Rep. 2024; 14(1): 16716.
24.Hyder Z, Hafeez Rizwani G, Shareef H, Azhar I, Zehra M. Authentication of important medicinal herbal species through DNA-based molecular characterization. Saudi J Biol Sci. 2024; 31(6): 103985.
25.Kantasrila R, Pandith H, Balslev H, Wangpakapattanawong P, Panyadee P, Inta A. Ethnobotany and phytochemistry of plants used to treat musculoskeletal disorders among Skaw Karen, Thailand. Pharm Biol. 2024; 62(1): 62-104.
26.Phumthum M, Nguanchoo V, Panyadee P, Inta A, Balslev H. Highly localised traditional knowledge of Mien medicinal plants in Chiang Rai, Thailand. People Nat. 2025; 7(1): 167-186.
27.Davies NMJ, Drinkell C, Utteridge T, editors. The Herbarium Handbook. 4th ed. Royal Botanic Gardens, Kew; 2023. 352 p.
28.Greene AM, Teixidor-Toneu I, Odonne G. To pick or not to pick: photographic voucher specimens as an alternative method to botanical collecting in ethnobotany. J Ethnobiol. 2023; 43(2): 134-151.
29.Jain, S. D., Shrivastava, S. K., Agrawal, A., & Gupta, A. K. WHO guidelines for quality control of herbal medicines: From cultivation to consumption. International Journal of Pharmaceutical Chemistry and Analysis. 2024; 1 11(3): 212–225.
30.Gaur P, Hada V, Rath RS, Mohanty A, Singh P, Rukadikar A. Good Agricultural and Collection Practices for medicinal plants: WHO guidelines implementation. Pharmcogn Rev. 2020; 14(27): 67-72.
31.Phuyal N, Jha PK, Raturi PP, Rajbhandary S. Total Phenolic, Flavonoid Contents, and Antioxidant Activities of Fruit, Seed, and Bark Extracts of Zanthoxylum armatum DC. ScientificWorldJournal. 2020; 2020: 8780704.
32.Lee SY, Lee HJ, Uh Y, Yong D, Lee K. Establishing quality control ranges for antimicrobial susceptibility testing of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus: a cornerstone to develop reference strains for Korean clinical microbiology laboratories. Ann Lab Med. 2015; 35(6): 583-591.
33.Clinical and Laboratory Standards Institute. Performance Standards for Antimicrobial Susceptibility Testing. 35th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2025.
34.Clinical and Laboratory Standards Institute. Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically. 11th ed. CLSI document M07. Wayne, PA: Clinical and Laboratory Standards Institute; 2018.
35.Urban F, Hajek K, Naber T, Anczykowski B, Schäfer M, Wegener J. PETER-assay: Combined Impedimetric Detection of Permeability (PE) and Resistance (TER) of Barrier-Forming Cell Layers. Sci Rep. 2020; 10(1): 7373.
36.Sonntag O, Loh TP. Calibration – an under-appreciated component in the analytical process of the medical laboratories. Adv Lab Med. 2024; 5(2): 148-152.
37.Schroeder S, Jaeger S, Schwer J, Seitz AM, Hamann I, Werner MS, Thorwaechter C, Santos I, Wendler T, Nebel D, Welke B. Accuracy measurement of different marker based motion analysis systems for biomechanical applications: A round robin study. PLoS One. 2022; 17(7): e0271349.
38.Kang H. Sample size determination and power analysis using the G*Power software. J Educ Eval Health Prof. 2021; 18: 17.
39.Alalwan HA, Kadhim MJ, Albukhaty S, Almurshedi AS, Al-Karagoly HK, Al-Musawi S. Methods for screening and evaluation of antimicrobial activity: a review of protocols, advantages, and limitations. Eur J Microbiol Immunol (Bp). 2024; 14(2): 97-126.
40.International Organization for Standardization. ISO 20776-1:2019 Clinical laboratory testing and in vitro diagnostic test systems — Susceptibility testing of infectious agents and evaluation of performance of antimicrobial susceptibility test devices — Part 1: Broth microdilution reference method for testing the in vitro activity of antimicrobial agents against rapidly growing aerobic bacteria involved in infectious diseases. Geneva: ISO; 2019.
41.Cohen J. Statistical power analysis for the behavioral sciences. 2nd ed. Hillsdale, NJ: Lawrence Erlbaum Associates; 1988.
42.Shah, D., Movaliya, V., Kharidia, S., & Zaveri, M. Comparative Study of Analytical Method Validation and Process Validation parameters as per ICH, EMA, WHO and ASEAN guidelines. International Journal of Drug Regulatory Affairs; 2024: 12(2), 58–64.
43.Gniazdowska, E., Gilant, E., & Bus‐Kwasnik, K. ICH M10 guideline - a harmonized global approach to bioanalysis. Biuletyn Wydziału Farmaceutycznego Warszawskiego Uniwersytetu Medycznego;2023: 21(3), 57–63.
44.Eberle, M. K., Wasylenko, J. T., Kostelac, D., Kiehna, S. E., Schellinger, A. P., Zhang, Z., & Ehrick, J. D. A Modern Framework for Analytical Procedure Development and Lifecycle Management Based on ICH Q14 Principles. Analytical Chemistr; 2024: 97(1), 12–21.
45.United States Pharmacopeial Convention. General chapter <51> Antimicrobial effectiveness testing. In: United States Pharmacopeia and National Formulary USP 43-NF 38. Rockville, MD: United States Pharmacopeial Convention; 2020.
46.Gniazdowska, E., Gilant, E., & Bus‐Kwasnik, K. (2023). ICH M10 guideline - a harmonized global approach to bioanalysis. Biuletyn Wydziału Farmaceutycznego Warszawskiego Uniwersytetu Medycznego; 2023:21(3), 57–63.
47.Dobroslavić E, Elez Garofulic I, Separović J, Zoric Z, Pedisic S, Dragovic-Uzelac V. Solvent-solute interactions in phytochemical extraction processes: theoretical principles and practical applications. Molecules. 2022; 27(16): 5099.
48.Shikov AN, Mikhailovskaya IY, Narkevich IA, Flisyuk EV, Pozharitskaya ON. Enhanced recovery of lipophilic compounds from medicinal plants using absolute ethanol extraction. In: Mukherjee PK, editor. Evidence-Based Validation of Herbal Medicine. 2nd ed. Amsterdam: Elsevier; 2022. p.771-796.
49.Sarakul O, Talabmuk C, Phosri S, Noysang C, Putthakarn N. Chemical analysis and bioactive compound profile of Tripitsajuk extract: eugenol as the predominant component. J Sci Technol Mahasarakham Univ. 2016; 35(5): 502-509.
50.Heinrich M, Appendino G, Efferth T, Furst R, Izzo AA, Kayser O, Lasak B, Mokry P, Moreno-Sanz G, Panfili G, Prieto JM, Tortoriello J, Wanner J, Williamson EM. Secondary metabolite profiles and therapeutic potential: diversity in traditional medicine formulations. J Ethnopharmacol. 2020; 246: 112230.
51.Konsue A, Taepongsorat L. Optimization of ethanol concentrations for diverse phytochemical extraction from Thai medicinal plants. J Ethnopharmacol. 2025; 330: 118562.
52.Olszewska MA, Gędas A, Simoes M. Synergistic effects in traditional multi-herb formulations: implications for bioactivity-guided extraction. LWT Food Sci Technol. 2020; 122: 109024.
53.Swamy MK, Akhtar MS, Sinniah UR. Compound selectivity versus extraction yield: fundamental principles in herbal medicine development. Molecules. 2022; 27(15): 4792.
54.Mayasari D, Islami D, Oktariani E, Wulandari P. Concentration-dependent antibacterial activity patterns of ethanol-based plant extractions against Gram-positive bacteria. Trop J Nat Prod Res. 2023; 7(1): 2157-2162.
55.Zhao A, Sun J, Liu Y. Bioactive compounds in traditional medicinal plants: eugenol, trans-cinnamaldehyde, citronellol, and terpineol effects against Escherichia coli biofilm formation. Front Cell Infect Microbiol. 2023; 13: 1137947.
56.ALrashidi A, Noumi E, Snoussi M, De Feo V. Synergistic antimicrobial effects of plant-derived compounds: eugenol, cinnamaldehyde, carvacrol, and thymol combinations against Escherichia coli. Plants (Basel). 2022; 11(4): 540.
57.Adianingsih OR, Ihsan BRP, Puspita OE, Maesayani KS. Chemical composition and eugenol content analysis in Syzygium aromaticum: HPLC validation and bioactivity correlation. Trop J Nat Prod Res. 2023; 7(8): 3395-3399.
58.Varela MF, Stephen JW, Bharti D, Lekshmi M, Kumar S. Multiple antimicrobial mechanisms of eugenol: bacterial cell membrane disruption, enzymatic interference, and protein synthesis inhibition. Biomedicines. 2023; 11(5): 1448.
59.Lorusso A, Carrara JA, Barroso CDN, Tuon FF, Faoro H. Quorum sensing pathway disruption by eugenol: suppression of virulence gene expression in Escherichia coli. Int J Mol Sci. 2022; 23(24): 15779.
60.Gultom E, Harahap U, Suryanto D, Sipahutar H, Restuati M. Antibacterial Activity of structurally diverse bioactive molecules including amino acids and organic compounds against Gram-negative pathogens including extended-spectrum beta-lactamase-producing Klebsiella pneumoniae. Trop J Nat Prod Res. 2024; 8(1): 37-42.
61.Langendonk RF, Neill DR, Fothergill JL. Mechanistic basis of eugenol's antibacterial activity: specific targeting of Gram-negative bacterial cytoplasmic membranes and membrane depolarization. Front Cell Infect Microbiol. 2021; 11: 665759.
62.Johnson MD, Reller LB, Petti CA, Jones RN. Eugenol disruption of Escherichia coli biofilm formation: implications for bacterial persistence and antibiotic resistance development. Diagn Microbiol Infect Dis. 2019; 95(3): 114865.
63.Amedu AB, Uba A, Chika M, Umar WRS. Enhanced antibacterial activity of green-synthesized nanoparticles derived from plant extracts: multi-target therapeutic strategies against Gram-positive and Gram-negative bacteria. Trop J Nat Prod Res. 2024; 8(5): 7285-7289.
64.Ouryemchi I, Oubihi A, Taibi M, Elbouzidi A, Jaber H, Haida S, Tarfaoui K, Atfaoui K, Chaabane K, El Guerrouj B, Bellaouchi R, Asehraou A, Addi M, Benzakour A, Ouhssine M. Minimum inhibitory concentrations of plant-derived extracts against Pseudomonas aeruginosa: elevated requirements and extended contact time for microbial reduction. Trop J Nat Prod Res. 2024; 8(3): 6663-6668.
65.Medeiros Filho F, Barbosa do Nascimento AP, Costa MOC, Merigueti TC, de Menezes MA, Nicolás MF, dos Santos M, Carvalho-Assef APD, da Silva FAB. Multiple therapeutic targets in Pseudomonas aeruginosa identified through integrated computational models: complex resistance mechanisms analysis. Front Mol Biosci. 2021; 8: 728129.
66.Qin S, Xiao WH, Zhou C, Pu Q, Deng X, Lan L, Liang H, Wu M. Pseudomonas aeruginosa: pathogenesis, virulence factors, antibiotic resistance mechanisms, sophisticated defense systems including efflux pumps, biofilm formation, and adaptive resistance. Signal Transduct Target Ther. 2022; 7(1): 239.
67.Al-Tamimi MA, Alshawwa SZ, Gomha SM, Abdelaziz MR. Plant extracts with elevated minimum inhibitory concentrations: Peganum harmala antimicrobial activity requiring significant contact time for Pseudomonas aeruginosa reduction. Molecules. 2020; 25(18): 4279.
68.Silva LN, Zimmer KR, Macedo AJ, Trentin DS. Plant natural products targeting bacterial virulence factors: outer membrane permeability differences between Escherichia coli and Pseudomonas aeruginosa affecting antimicrobial penetration. Curr Med Chem. 2016; 23(14): 1389-1409.
69.Cigana C, Melotti P, Baldan R, De Simone M, Einarsson GG, Shaw D, Bevivino A, Morales S, Schwartz S, Sipione B, Turano C, Gaiarsa S, Sassera D, Bevec T, Twomey KB, O'Gara F, Ratjen F, Bragonzi A. Pseudomonas aeruginosa outer membrane lipopolysaccharides with longer O-antigen chains and lipid A modifications: enhanced barrier against hydrophobic compounds. J Cyst Fibros. 2017; 16(4): 469-477.
70.AB, Carrara JA, Barroso CDN, Tuon FF, Faoro H. Role of Efflux Pumps on Antimicrobial Resistance in Pseudomonas aeruginosa. Int J Mol Sci. 2022;23(24):15779.
71.Laborda P, Lolle S, Hernando-Amado S, Alcalde-Rico M, Aanæs K, Martínez JL, Molin S, Johansen HK. Mutations in the efflux pump regulator MexZ shift tissue colonization by Pseudomonas aeruginosa to a state of antibiotic tolerance. Nat Commun. 2024;15(1):2584.
72.World Health Organization. Global priority list of antibiotic-resistant bacteria to guide research, discovery, and development of new antibiotics. Geneva: World Health Organization; 2017.
73.Tadesse BT, Ashley EA, Ongarello S, Havumaki J, Wijegoonewardena M, Gonzalez IJ, Dittrich S. Antimicrobial resistance in Africa: a systematic review and meta-analysis of zone-of-inhibition studies demonstrating variation between Gram-negative and Gram-positive bacterial strains with enhanced activity against Gram-positive organisms. PLoS One. 2017; 12(12): e0189749.