Obvladovanje biofilmov MRSA s hladno atmosfersko plazmo : magistrsko delo

Lunder, Manca (author), Fink, Rok (mentor), Dahle, Sebastian (comentor), Oder, Martina (reviewer)

Uvod: Bakterijska protimikrobna odpornost predstavlja vse večjo grožnjo za zdravje ljudi tako v razvitem kot nerazvitem svetu. Širjenje bakterijskih okužb v vsakdanjem življenju obvladujemo s številnimi protimikrobnimi sredstvi, vendar ima ta pristop pogosto negativen vpliv na naše zdravje in okolje. Zaradi vse večje odpornosti bakterij na antibiotike smo se v naši raziskavi osredotočili na potencial obvladovanja biofilmov MRSA s pomočjo plazme. Plazma proizvaja reaktivne kisikove in dušikove zvrsti, ki že v nizkih koncentracijah pripomorejo k protibakterijski aktivnosti. Namen: Namen magistrskega dela je bil ugotoviti, pri kakšnih pogojih lahko s plazmo nadzorujemo biofilme S. aureus in biofilme njegove, na meticilin odporne različice – MRSA. Metode dela: Učinkovitost plazme na biofilme S. aureus in MRSA smo analizirali z uporabo različnih metod dela. Uporabili smo metode štetja kolonij, merjenja fluorescence po dodatku resazurina in metodo merjenja optične gostote. Analize smo izvedli ločeno za oba bakterijska seva. Analizirali smo učinkovitost 60, 120 in 180 s izpostavljenosti plazmi na različno zrele oz. stare biofilme (24, 48 in 72 h). Rezultati: Učinkovitost plazme na biofilme S. aureus in MRSA se je povečevala sorazmerno z daljšim časom izpostavljenosti, kar smo potrdili z metodami preverjanja živosti, metabolizma, oksidativnega stresa in z mikroskopiranjem. Plazma v splošnem ni imela vpliva na povečanje ali zmanjšanje biomase biofilmov S. aureus in MRSA. Pojava odpornosti obeh bakterijskih sevov na plazmo ali na Cefoksitin 30 v 10 generacijah bakterij nismo zabeležili. Razprava in zaključek: V sklopu naše raziskave smo učinkovitost plazme dokazali z različnimi metodami, s katerimi smo prišli do enakih izsledkov. Z daljšim časom izpostavljenosti biofilmov S. aureus in MRSA plazmi se zmanjšata živost in metabolna aktivnost obeh bakterijskih sevov. Z daljšim časom izpostavljenosti plazmi so dokazali tudi povečanje oksidativnega stresa tako pri S. aureus kot MRSA. Plazma je biomaso biofilmov za statistično pomembne razlike odstranila le v primeru 72 h biofilmov. 10-kratna izpostavljenost biofilmov S. aureus in MRSA ni privedla do večje oz. manjše odpornosti na plazmo ali Cefoksitin 30. Poleg visoke baktericidne učinkovitosti je prednost uporabe plazme tudi njena nizka toksičnost, saj v nasprotju s kemijsko dezinfekcijo površin nima škodljivega vpliva na okolje.

• Language: Slovenian
• Keywords: magistrska dela, sanitarno inženirstvo, hladna atmosferska plazma, MRSA, biofilmi
• Work type: Master's thesis/paper
• Typology: 2.09 - Master's Thesis
• Organization: ZF - Faculty of Health Sciences
• Place of publishing: Ljubljana
• Publisher: [M. Lunder]
• Year: 2023
• Number of pages: 63 str., [10] str. pril.
• PID: 20.500.12556/RUL-152457
• UDC: 614
• COBISS.SI-ID: 173772547
• Publication date in RUL: 26.11.2023

Secondary language

• Language: English
• Title: MRSA biofilm management with cold atmospheric plasma : master thesis

Abstract

Introduction: Bacterial antimicrobial resistance poses a growing threat to human health in developed and underdeveloped regions worldwide. The spread of bacterial infections is controlled by many antimicrobial agents, but this approach often has a negative impact on our health. Due to the growth of antibiotic resistance in bacteria, our thesis will focus on the potential of plasma-based biofilm control of MRSA. Plasma produces reactive oxygen and nitrogen species which, even at low concentrations, exhibit remarkable antimicrobial properties. Aim: The aim of our research was to investigate the conditions under which plasma can effectively eliminate S. aureus and MRSA biofilms. Methods: Various methods, including colony counting, fluorescence measurements following resazurin addition, and optical density measurements were employed to separately analyze the two bacterial strains. The efficacy of 60, 120, and 180 s of plasma exposure on biofilms of different maturity (24, 48, and 72 h) was analyzed. Results: The efficacy of plasma against S. aureus and MRSA biofilms increased proportionally with increasing exposure time, as confirmed by viability, metabolism, oxidative stress, and microscopy observations. Notably, plasma had no overall effect on the increase or decrease of S. aureus and MRSA biofilm biomass. The emergence of resistance of both bacterial strains to plasma or to cefoxitin 30 was not observed in 10 bacterial generations. Discussion and conclusion: With prolonged exposure of S. aureus and MRSA biofilms to plasma, the viability and metabolic activity of both bacterial strains were reduced. Furthermore, as exposure time to plasma increased, oxidative stress in both S. aureus and MRSA was also heightened, further indicating the impact of plasma on these biofilms. Plasma treatment resulted in the removal of biofilm biomass only in the case of 72 h biofilms. Encouragingly, our investigation spanning 10 bacterial generations of plasma-exposed bacteria did not lead to any notable emergence of resistance to plasma or cefoxitin 30. In addition to its high bactericidal efficacy, plasma has the advantage of low toxicity, since, unlike chemical surface disinfection, it has no adverse impact on the environment.

• Keywords: master's theses, sanitary engineering, cold atmospheric plasma, MRSA, biofilms