Karakterizacija biofilma klavniških in okoljskih sevov bakterij Campylobacter jejuni

Zajkoska, Sandra (avtor), Smole Možina, Sonja (mentor)

Bakterijska adhezija in tvorba biofilma sta v živilski industriji lahko zelo problematična, saj so bakterijske celice znotraj biofilma bolj odporne na različne okoljske dejavnike. Tudi za Campylobacter jejuni je sposobnot tvorbe biofilma zelo pomembna za preživetje zunaj gostitelja. Namen eksperimentalnega dela magistrske naloge je bil karakterizirati biofilm 16 različnih sevov C. jejuni, izoliranih v klavniškem okolju ter iz površinskih vod, pri različnih pogojih (v MHB gojišču pri 42 ºC in 37 ºC, mikroaerofilno ter 8 ºC, aerobno in v MHB z dodatkom piščančjega izcedka pri 37 ºC, mikroaerofilno ter 8 ºC, aerobno). Kot kontaktno površino smo izbrali nerjavno jeklo, saj je to zelo pogosto uporabljen material v živilsko-predelovalnih obratih. Formirani biofilm na površini jeklenih diskov smo kvantificirali z gojitveno metodo in kolorimetrično metodo. Ob pogojih, 37 ºC, mikroaerofilno v MHB z dodanim piščančjim izcedkom in 42 ºC, mikroaerofilno v gojišču MHB so bili, povprečno, klavniški sevi bolj filmotvorni kot okoljski. Potrdili smo, da ima izcedek piščančjega mesa pomembno vlogo pri filmotvornosti bakterij C. jejuni. V nadaljevanju smo testirali tudi protimikrobno delovanje etanolnega izvlečka kraškega šetraja (Satureja montana) in benzalkonijevega klorida ter njuno sposobnost zmanjšanja števila že formiranih biofilmskih celic. Vsi sevi C. jejuni so bili dovzetni na obe testirani spojini, vedar je bil benzalkonijev klorid veliko bolj učinkovit. Obe testirani spojini sta pokazali tudi dober učinek zmanjšanja števila biofilmskih celic. Pri sevu C. jejuni B0975, enemu izmed najboljših filmotvorcev, smo določili tudi občutljivost planktonskih in biofilmskih celic na izbrane protimikrobne spojine, testirali membransko integriteto celic in določili količino akumuliranega etidijevega bromida v celicah. S tem smo želeli primerjati odpornost planktonskih in biofilmskih celic C. jejuni. Večje odpornosti biofilmskih celic z uporabljenimi metodami ne moremo potrditi.

• Jezik: Slovenski jezik
• Ključne besede: patogeni mikroorganizmi, Campylobacter jejuni, bakterijska adhezija na abiotski površini, biofilmi, klavniški sevi, okoljski sevi, protimikrobno delovanje, kraški šetraj, Satureja montana, benzalkonijev klorid
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: BF - Biotehniška fakulteta
• Založnik: [S. Zajkoska]
• Leto izida: 2020
• PID: 20.500.12556/RUL-113670
• UDK: 579.22/.26:547.9:615.281
• COBISS.SI-ID: 5166968
• Datum objave v RUL: 23.01.2020

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Biofilm characterization of slaughterhouse and environmental isolates in Campylobacter jejuni

Izvleček

Bacterial adhesion and biofilm formation can be very problematic in the food industry, as bacterial cells within the biofilm are more resistant to various environmental factors. For Campylobacter jejuni, biofilm formation is also very important for their survival outside the host. The purpose of the experimental part of the master's thesis was to characterize the biofilm of 16 different C. jejuni strains isolated in the slaughterhouse environment and from surface waters under different conditions (in MHB medium at 42 ºC in 37 ºC in microaerobic atmosphere and 8 ºC in aerobic atmosphere and in MHB with added chicken juice at 37 ºC in microaerobic atmosphere and 8 ºC in aerobic atmosphere). Stainless steel was chosen as the contact surface because it is a very commonly used material in food processing plants. The formed biofilm on the surface of the steel disks was quantified by the cultivation method and the colorimetric method. At 37 ºC in MHB supplemented with chicken juice in microaerobic atmosphere and 42 ºC in MHB in microaerobic atmosphere on average were slaughterhouse strains more biofilm-forming than environmental strains. We have confirmed that chicken juice plays an important role in the proces of biofilm formation of C. jejuni. In addition, we tested the antimicrobial activity of the ethanol extract of S. montana and benzalkonium chloride and their ability to reduce already formed biofilms. All C. jejuni strains were susceptible to both tested compounds, but benzalkonium chloride was much more effective. Both tested compounds also showed good biofilm reduction effect. In C. jejuni B0975 strain, one of the best biofilm formers, we determined the sensitivity of planktonic and biofilm cells to selected antimicrobial compounds, tested the membrane integrity of the cells and determined the amount of accumulated ethidium bromide in the cells. With this we wanted to compare the resistance of planktonic and biofilm cells of C. jejuni. Increased resistance of biofilm cells by the methods used cannot be confirmed.

• Ključne besede: pathogenic microorganisms, Campylobacter jejuni, bacterial adhesion on abiotic surface, biofilms, slaughterhouse strains, environmental strains, antimicrobial activity, winter savory, Satureja montana, benzalkonium chloride