Preskušanje protimikrobnega delovanja nitritne bakterije Nitrosomonas eutropha : univerzitetni študijski program Kozmetologija

Virant, Urška (author), Lunder, Mojca (mentor), Močnik Roner, Maša (comentor)

V kozmetični industriji je eden izmed najnovejših trendov kozmetika s probiotiki. Gre za kozmetične izdelke, ki vsebujejo žive organizme, ki v primerni količini delujejo koristno na zdravje gostitelja. Njihov namen v kozmetičnih izdelkih je povečanje barierne funkcije kože, zmanjšanje rasti patogenov, pospeševanje procesa celjenja ran in spodbujanje delovanja imunskih celic. Eden izmed kozmetičnih izdelkov s probiotiki je tudi izdelek Ao+MistTM, ki smo ga preskušali v diplomski nalogi. Ob redni uporabi naj bi bila koža bolj gladka, mehkejša, izboljšalo pa naj bi se tudi stanje mastne, suhe in občutljive kože. Vsebuje nitritne bakterije Nitrosomons eutropha D23 (N. eutropha D23), ki delujejo tako, da izkoriščajo amonijak iz znoja in ga pretvarjajo v nitrit in dušikov monoksid. Dušikov monoksid je majhna reaktivna dvoatomna molekula, ki ima različne biološke učinke, odvisne od koncentracije in časa izpostavljenosti. V dobi rastoče rezistence na antibiotike, se pojavlja kot obetavno širokospektralno topikalno protimikrobno sredstvo, z majhno verjetnostjo razvoja rezistence zaradi različnih mehanizmov delovanja na patogene. Zaradi tega naj bi imel ta kozmetični izdelek tudi protimikrobno delovanje. Glavni namen je bil preskusiti ali nitritna bakterija N. eutropha D23 zavira rast oportunističnih mikroorganizmov Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus in Aspergillus brasiliensis z difuzijsko metodo z diski. Pred tem smo preverili ali izdelek vsebuje bakterije N. eutropha D23, jim določili optimalno gojišče za rast in jih gojili do primerne koncentracije za nadaljnjo uporabo. Opazovali smo tudi, kako različni dejavniki vplivajo na rast in aktivnost bakterij. Koncentracijo bakterij smo določali s pomočjo merjenja optične gostote pri 600 nm, aktivnost pa smo določili z merjenjem koncentracije nitrita, tako da smo merili absorbanco pri 352 nm in 400 nm. Rezultati eksperimentalnega dela so pokazali, da izdelek Ao+MistTM vsebuje bakterije N. eutropha D23, s koncentracijo 109 CFU/mL. Najbolj optimalni pogoji za gojenje so bili v tekočem gojišču B na 30 °C, v temi in pri konstantnem stresanju. N. eutropha D23 ni zavirala rasti nobenega od testnih mikroorganizmov. Iz naših rezultatov in vitro poskusa, bi lahko sklepali, da bakterija ne zavira rasti drugih mikroorganizmov, kar je v nasprotju z objavljenimi trditvami. Zato bi bilo smiselno preskusiti delovanje bakterij N. eutropha D23 z razredčitvenim testom, kot tudi in vivo, saj bi se lahko pojavilo sinergistično delovanje s celicami imunskega sistema. Bakterije N. eutropha so samo eden izmed dostavnih sistemov dušikovega monoksida, razvijajo pa se še številni novi, ki bi zagotavljali podaljšano sproščanje in varnost do gostiteljskih celic.

• Language: Slovenian
• Keywords: Nitrosomonas eutropha dušikov monoksid protimikrobno delovanje difuzijski test
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FFA - Faculty of Pharmacy
• Place of publishing: Ljubljana
• Publisher: [U. Virant]
• Year: 2018
• Number of pages: XII, 44 str.
• PID: 20.500.12556/RUL-120140
• UDC: 579.8:613.292(043.2)
• COBISS.SI-ID: 4575857
• Publication date in RUL: 16.09.2020

Secondary language

• Language: English
• Title: Antimicrobial activity of nitrosifying bacteria Nitrosomonas eutropha

Abstract

One of the latest trends in the cosmetic industry is cosmetics with probiotics. These are cosmetic products that contain living non-pathogenic organisms which, when administered in adequate amounts, confer a health benefit. Their purpose in cosmetic products is to improve the barrier function of the skin, to inhibit the growth of the pathogen, to stimulate the wound healing process and action of immune cells. One of these products is also the Ao+MistTM, which we tested. During regular application, the skin should be smoother, and conditions of greasy, dry and sensitive skin are supposed to be improved.It contains nitrosifying bacteria Nitrosomonas eutropha D23 (N. eutropha D23) that converts ammonia in sweat to nitrite and nitric oxide. In an era of the increasing bacterial resistance to available antibiotics, nitric oxide appears as a promising topical broad-spectrum antimicrobial agent with a small likelihood of resistance development because of various mechanisms of action on pathogens. The main purpose of this work was to test the antimicrobial activity of nitrosifying bacteria N. eutropha D23 on Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus, and Aspergillus brasiliensis by the discs diffusion test method. First, we tested if the product contains bacteria N. eutropha D23, determined the optimal growth medium and grown them to a suitable concentration for further use. We also observed how different factors affect the growth and activity of these bacteria. The concentration of bacteria was determined by measuring the optical density at 600 nm. Their activity was determined by measuring the concentration of nitrite spectrophotometrically at 352 nm and 400 nm. Results showed that the cosmetic product Ao+MistTM, contains bacteria N. eutropha D23 with concentration 109 CFU/mL. The most optimal cultivation conditions were in liquid medium B at 30 °C in darkness and with constant mixing. Bacteria N. eutropha D23 showed no antimicrobial activity on any of the tested microorganisms. From our in vitro results we concluded that N. eutropha D23 does not prevent the growth of tested microorganisms, which is contrary to the published claims. To confirm this antimicrobial activity should be additionally tested with dilution test as well as in vivo, where synergistic action with the cells of the immune system could occur. Bacteria N. eutropha is just one of the nitric oxide delivery systems. Many new ones are also being developed to provide controlled nitric oxide release and safety to host cells.

• Keywords: Nitrosomonas eutropha nitric oxide probiotics antimicrobial activity disc diffusion test