diplomsko delo
Tina Bekrić (Author), Blaž Cigić (Reviewer), Barbara Jeršek (Mentor)

Abstract

Čiščenje in razkuževanje sta pomembna tekom celotne proizvodno-prodajne živilske verige. Z ustrezno metodo čiščenja in izborom razkužila lahko učinkovito preprečujemo kontaminacijo živil z nezaželenimi mikroorganizmi. V okviru diplomskega dela smo določili protibakterijsko delovanje klorheksidin diacetata. Aktivnost smo ovrednotili z določitvijo minimalne inhibitorne koncentracije (MIC) klorheksidin diacetata z bakterijami vrst Listeria monocytogenes (kot grampozitivne bakterije), Staphylococcus aureus (kot toksigene bakterije), Bacillus cereus (kot sporogene bakterije), Escherichia coli in Salmonella enterica (kot gramnegativne bakterije). MIC smo določili z metodo razredčevanja v mikrotitrski ploščici, kjer smo po dodatku reagenta INT (2-p-iodofenil-3-p-nitrofenil-5-fentil tetrazolijev klorid) določili metabolno aktivne bakterije. Število preživelih bakterij smo nato določili še z metodo štetja kolonij na trdem gojišču. Najbolj učinkovito je razkužilo delovalo na grampozitivne bakterije vrst Staph. aureus in L. monocytogenes, kjer je povprečna MIC znašala 0,9±0,3 mg/l. Povprečna MIC pri gramnegativnih bakterijah vrste E. coli je bila 1,1±0,3 mg/l in pri bakterijah vrste S. enterica 8,7±2,5 mg/l. Sporogene bakterije vrste B. cereus so imele MIC pri 1,5±0,6 mg/l. Hipotezo, da so gramnegativne bakterije vrst E. coli in S. enterica bolj odporne proti klorheksidin diacetatu kot grampozitivne bakterije vrst Staph. aureus, B. cereus in L. monocytogenes lahko potrdimo, čeprav bi za podrobnejše rezultate rabili večji obseg raziskovalnega dela. Sporogene grampozitivne bakterije vrste B. cereus so bolj odporne proti razkužilu kot nesporogene grampozitivne bakterije. Uporaba ustreznih koncentracij razkužila klorheksidina zmanjša prisotnost bakterij.

Keywords

razkužila;klorheksidin;protibakterijska učinkovitost;razredčevanje v mikrotitrski ploščici;minimalna inhibitorna koncentracija;Listeria monocytogenes;Staphylococcus aureus;Bacillus cereus;Escherichia coli;Salmonella enterica;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [T. Bekrić]
UDC: 579.24:615.281
COBISS: 32255235 Link will open in a new window
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Downloads: 122
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Other data

Secondary language: English
Secondary title: Antibacterial activity of chlorhexidine
Secondary abstract: Cleaning and disinfection have big importance through the production, manufacturing and distribution of food. With proper cleaning method and selection of disinfectants we can effectively prevent contamination of foods with unwanted microorganisms. Within the diploma work we investigated antibacterial activity of chlorhexidine diacetate. The activity was evaluated by determining minimum inhibitory concentration (MIC) for different bacteria, as follows, Listeria monocytogenes (as gram-positive bacterium), Staphylococcus aureus (as toxigenic bacterium), Bacillus cereus (as sporogenic bacterium), Escherichia coli and Salmonella enterica (as gram-negative bacteria). MIC was determined by micro-dilution method after adding INT reagent (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-tetrazolium chloride) that dyed metabolic active bacterial cells. The number of surviving bacteria was also determined with the plate count method. Chlorhexidine diacetate was the most efficient for gram-positive Staph. aureus and L. monocytogenes stains, where the MIC was 0.9±0.3 mg/l. The gram-negative E. coli strain had MIC of 1.1±0.3 mg/l. The gram-negative S. enterica strain had the highest MIC of 8.7±2.5 mg/l. Sporogenic B. cereus had MIC of 1.5±0.6 mg/l. The hypothesis that gram-negative bacteria such as E. coli and S. enterica are more resistant to chlorhexidine diacetate than gram-positive bacteria such as Staph. aureus, B. cereus and L. monocytogenes was confirmed. Sporogenic bacteria like B. cereus were more resistant than non-sporogenic gram-positive bacteria. Usage of appropriate concentrations of chlorhexidine decrease the presence of bacteria.
Secondary keywords: disinfectants;chlorhexidine;antibacterial efficacy;dilution in a microtiter plate;minimum inhibitory concentration;Listeria monocytogenes;Staphylococcus aureus;Bacillus cereus;Escherichia coli;Salmonella enterica;
Type (COBISS): Bachelor thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za živilstvo
Pages: VII, 21 f.
ID: 12035082