1. Antimicrobial properties of different hop (Humulus lupulus) genotypesZala Kolenc, Tomaž Langerholc, Gregor Hostnik, Miha Ocvirk, Sara Štumpf Horvat, Maša Pintarič, Iztok Jože Košir, Andreja Čerenak, Alenka Garmut, Urban Bren, 2023, original scientific article Abstract: The antimicrobial activity of hop extracts obtained from different hop genotypes were investigated against Staphylococcus aureus and Lactobacillus acidophilus. In this study the pure xanthohumol, purified β-acids rich fraction, as well as α-acids with β-acids rich fraction were used to test antimicrobial activity against Staphylococcus aureus and Lactobacillus acidophilus; whereby, the antimicrobial activity of different hop extracts against Lactobacillus acidophilus was studied for the first time. Microbial susceptibility to purified hydroacetonic extracts from different hop varieties was investigated by the broth microdilution assay to determine the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The hop hydroacetonic extracts were more effective against Staphylococcus aureus than against Lactobacillus acidophilus. Strong inverse correlations of MIC and MBC values were obtained with xanthohumol, cohumulone, n+adhumulone, colupulone and n+adlupulone contents, suggesting that the identified chemical hop compounds are directly responsible for antimicrobial effects. Moreover, the effect of the growth medium strength on the MIC values of hop extracts against Staphylococcus aureus was systematically investigated for the first time. The current study also reveals the effect of different hop extracts on Staphylococcus aureus, which responds to their presence by lag phase extension and generation time prolongation.
Keywords: hop extract, xanthohumol, Staphylococcus aureus, Lactobacillus acidophilus, minimum inhibitory concentration, minimum bactericidal concentration
Published in DKUM: 09.05.2024; Views: 203; Downloads: 22
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2. The Influence of Chestnut Extract and Its Components on Antibacterial Activity against Staphylococcus aureusSara Štumpf Horvat, Gregor Hostnik, Tomaž Langerholc, Maša Pintarič, Zala Kolenc, Urban Bren, 2023, original scientific article Abstract: Increasing antimicrobial resistance has caused a great interest in natural products as alternatives or potentiators of antibiotics. The objective of this study was to isolate individual tannins from crude chestnut extract as well as to determine the influence of both crude extracts (tannic acid extract, chestnut extract) and individual pure tannins (gallic acid, vescalin, vescalagin, castalin, castalagin) on the growth of Gram-positive Staphylococcus aureus bacteria. Their antibacterial activity was monitored by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) as well as the duration of the lag phase, growth rate and generation time. The effect of growth medium strength on the MIC of different tannins was also investigated. Bacterial growth was followed spectrophotometrically, and MIC values were determined by the microdilution method. The MIC values of various isolated compounds allowed us to determine the bioactive compounds and their contribution to antimicrobial activity. It was found that MIC values increase with increasing growth medium strength and that the lag phase lengthens with increasing tannin concentrations, while the growth rates decrease. Comparing the results of the two studies, the antimicrobial activity of tannins against S. aureus was not as pronounced as in the case of E. coli, which may indicate that a different mechanism of action is responsible for the antimicrobial effects of tannins on Gram-positive than on Gram-negative bacteria, or that a different mechanism is more pronounced.
Keywords: tannins, antibacterial activity, MIC, MBC, Staphylococcus aureus, lag phase, generation time
Published in DKUM: 20.02.2024; Views: 363; Downloads: 73
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4. Epidemiološki in mikrobiološki pristopi za spremljanje bolnišničnih okužb v UKC MariborBožena Kotnik Kevorkijan, 2019, doctoral dissertation Abstract: Bolnišnične okužbe (BO) so okužbe, povezane z zdravstveno oskrbo (OPZ), ki nastanejo v bolnišnici in predstavljajo najpogostejši zaplet zdravljenja v bolnišnici. Spremljanje njihove pogostosti se lahko uporablja kot kazalnik kakovosti za bolnišnice. K spremljanju spreminjanja pogostosti BO lahko pristopimo tudi s ponavljajočimi se presečnimi raziskavami BO. Evropski center za preprečevanje in obvladovanje bolezni (angl. European Centre for Disease Prevention and Control, ECDC) vsakih pet let koordinira izvedbo evropske presečne raziskave BO.
Leta 2011 smo v Sloveniji opravili drugo Slovensko nacionalno presečno raziskavo BO (SNPRBO II), prevalenčno presečno raziskavo na dan (angl. point prevalence survey - PPS) v okviru evropske prevalenčne presečne raziskave BO. V raziskavi je sodeloval tudi Univerzitetni klinični center (UKC) Maribor. Visoko usposobljena zdravnica za obvladovanje in preprečevanje BO (ZOBO) je v UKC Maribor opravila vzporedno validacijo metode zbiranja podatkov, ki so jih zbrali anketarji v skladu s standardizirano metodologijo zbiranja podatkov, ki jo priporoča ECDC. Preverila je pravilnost zabeleženih podatkov za vse bolnike, pri katerih so anketarji prepoznali BO, in za vsakega petega bolnika, pri katerem anketarji niso prepoznali BO.
Ob spremljanju širjenja mikroorganizmov znotraj bolnišnice in prepoznavanju izbruhov je pomembna tipizacija mikroorganizmov, ki so povzročili BO. V UKC Maribor smo se odločili za tipizacijo proti meticilinu odpornih zlatih stafilokokov (angl. Methicillin resistant Staphylococcus aureus, MRSA), saj je spremljanje MRSA obvezni kazalnik kakovosti v slovenskih bolnišnicah. Tipizirali smo tudi bakterijo Clostridium difficile (CD), saj marsikje v zdravstveno razvitih državah CD predstavlja kazalnik kakovosti in povzroča klinično pomembne okužbe. Za MRSA smo uporabili spa tipizacijo, za CD pa ribotipizacijo.
Cilji doktorske naloge so vključevali: razvoj modificirane, delovno intenzivnejše metode za validacijo uporabljene »običajne ECDC metode« za prepoznavanje BO v presečni raziskavi (»modificirana ECDC metoda«); ocenili smo prevalence BO ob uporabi »običajne ECDC metode« in »modificirane ECDC metode«, razvite v okviru doktorske naloge; občutljivost in specifičnost »običajne ECDC metode« za prepoznavanje BO v primerjavi z »modificirano ECDC metodo« ter potrebo po nadomestitvi »običajne ECDC metodo« z našo »modificirano ECDC metodo«. Opisali smo značilnosti bolnikov, vključenih v presečno raziskavo, izpostavljenost invazivnim postopkom, BO, izolirane mikroorganizme in odpornost nekaterih mikroorganizmov na izbrane antibiotike ali skupine antibiotikov, ter uporabo antibiotikov. Spremljali smo dva izbrana povzročitelja BO, MRSA in CD, v časovnem obdobju enega leta in ocenili pomen molekularnih tipizacij za prepoznavanje in nadzor BO.
V PPS smo vključili 991 bolnikov, to je vse bolnike, ki so bili hospitalizirani v UKC Maribor na dan raziskave. O vsakem smo zabeležili številne podatke, tudi o dejavnikih tveganja za BO, zdravljenju s protimikrobnimi sredstvi in BO. Z obema metodama smo prepoznali 52 bolnikov, ki so na dan raziskave imeli vsaj eno BO oziroma so bili na dan raziskave še vedno zdravljeni zaradi BO. Ustrezna ocena prevalence BO je bila 5,2 % (s 95 % intervalom zaupanja 3,9 % - 6,8 %). Največ BO so imeli bolniki v enotah za intenzivno zdravljenje (EIZ) 25,0 %, na kirurških oddelkih je imelo BO 6,2 % bolnikov, na ginekološkem in porodnem oddelku 4,4 %, na internih oddelkih 3,1 % bolnikov.
Z univariatnimi in multivariatnimi analizami smo opredelili neodvisne dejavnike tveganja za BO: prisotnost vsadka v zadnjem letu, prisotnost urinskega katetra, operacija v zadnjih 30 dneh in intubacija.
Skupno smo prepoznali 66 BO. Najpogostejše so bile okužbe spodnjih dihal (25 %), okužbe kirurške rane in okužbe sečil. 9 % BO je bilo prisotnih že ob sprejemu bolnika v UKC Maribor, 91 % BO pa je bilo pridobljenih v času aktualne hospitalizacije, največ v obdobju 4.–7. dne po sprejemu. V
Keywords: bolnišnične okužbe, presečna raziskava, prevalenca, proti meticilinu odporen Staphylococcus aureus - MRSA, Clostridium difficile, spa tipizacija, ribotipizacija
Published in DKUM: 14.01.2020; Views: 1926; Downloads: 459
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5. Comparison of methods for detection of four common nosocomial pathogens on hospital textilesSabina Fijan, Sonja Šostar-Turk, Urška Rozman, 2014, original scientific article Abstract: Introduction: Although the most common vehicle for transmission of health-care acquired infections is the personto- person transmission route, the role of environment should not be ignored and hospital linen may contribute to the spreading of nosocomial infections. The contact plate method and swabbing are common methods for sampling microorganisms on textiles; however, results are available after two days as they are based on incubation followed by phenotypeidentification. An important alternative is using quick wash-off methods followed by PCR detection, which shortens the identification process from two days to a few hours.
Methods: The following test microorganisms at different concentrations were inoculated onto textile swatches and dried overnight: Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa and Clostridium difficile. RODAC plate sampling as well as a non-destructive wash-off method for capturing microorganisms from the textilesusing a Morapex device were used. The elution suspension from the Morapex device was used for two methods. In the first method, classical incubation on selective media followed by phenotypic identification was used and in the second method DNA was extracted from the elution suspension followed by amplification and agarose gel electrophoresis to visualize amplified products.
Conclusions: All chosen bacteria were found using all methods. However, the most sensitive proved to be detection using PCR amplification as we detected the sample with initial concentration of 102 cfu/mL inoculated onto the textile surface before drying. The final detectablerecovered bacterial concentration on textiles was up to 10 cfu/mL.
Keywords: health care associated infections, hospital textiles, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Clostridium difficile, Morapex
Published in DKUM: 05.04.2017; Views: 2185; Downloads: 431
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6. Real-time polymerase chain reaction for quantitative assessment of common pathogens associated with healthcare-acquired infections on hospital textilesUrška Rozman, Sabina Fijan, Sonja Šostar-Turk, Vid Mlakar, 2013, original scientific article Abstract: A hospital environment may act as a significant reservoir for potential pathogens that can be transmitted with hospital textiles, which could represent a source of healthcare-acquired infections. Quantitative assessment of nosocomial pathogens with real time polymerase chain reaction (qPCR) on textiles can serve to verify the achievement of standards for textile hygiene of hospital laundry that assess the risk for acquiring hospital infection frominappropriately disinfected textiles. The aim of the study was to establish qPCR for quantitative assessment of selected common nosocomial pathogens (Clostridium difficile, Staphylococcus aureus, Klebsiella pneumoniaeand Pseudomonas aeruginosa) on hospital textiles and to compare the efficiency of the molecular method to the standard procedures for evaluating the bio burden of textiles in hospitals. This study demonstrated that presenceof nosocomial pathogens on hospital textiles can be confirmed with qPCR even where conventional techniques do not give any results. qPCR offers apossibility to confirm the presence of microorganisms in dead or viable but non-culturable states that cannot be detected by conventional sampling techniques but may still pose a hazard to public health.
Keywords: healthcare-acquired infections, hospital textiles, Clostridium difficile, Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa
Published in DKUM: 10.07.2015; Views: 1875; Downloads: 132
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7. Efficiency of four sampling methods used to detect two common nosocomial pathogens on textilesUrška Rozman, Sonja Šostar-Turk, Sabina Fijan, 2012, original scientific article Abstract: Detecting microorganisms on textiles is useful for many purposes, for example to determine the bioburden before laundering, assess the reduction in bacterial counts in connection with various laundry processes, or trace transfer routes in infection control investigations. Therefore a validated, reproducible and rational method is needed. For sampling microorganisms on textile surfaces the most commonly used method is the contact plate method using RODAC plates, first described by Hall and Hartnett followed by the swab sampling technique. Both methods can only capture microorganisms on the surface of the textiles while microorganisms that have penetrated into the deeper structure of the material will not be detected. In our research the contact plate method and the swabbing technique were compared with two wash-off methods. For the first wash-off method the destructive elution methodwas used, where microorganisms were eluted from the fabrics by shaking the fabrics for a certain time in an elution medium. For the fourth sampling method a nondestructive method that included a compact test device called MorapexŽ was used, which is based on forced desorption by pressing the microorganisms through the fabric without destroying the fabric. In our research, two types of microorganisms were included (Klebsiella pneumoniae andStaphylococcus aureus) that cause common nosocomial infections. The aim of this study was to compare the efficiency of the four sampling methods for detecting microorganisms on textiles and to determine the lowest concentration, which can still be detected. The percentage of microorganisms that were detected by both elution methods was substantially higher than by sampling of fabrics with the contact plate method or swabbing. It can be concluded that a nondestructive method using a modified MorapexŽ device can beapplied for quick determination of the hygienic condition of textiles.
Keywords: textile hygiene, Staphylococcus aureus, Klebsiella pneumoniae, swabbing, RODAC plates, elution method, Morapex
Published in DKUM: 10.07.2015; Views: 1701; Downloads: 116
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9. DOLOČEVANJE MEJE DETEKCIJE IZBRANIH MIKROORGANIZMOV NA RAZLIČNIH POVRŠINAH V BOLNIŠNIČNEM OKOLJU Z METODO PCRPatricija Murko, 2015, master's thesis Abstract: Izhodišča: V magistrski nalogi smo določevali mejo detekcije izbranim mikroorganizmom na različnih površinah v bolnišničnem okolju. Prenos s človeka na človeka je najbolj pogost, saj je v bolnišničnem okolju veliko pacientov, prav tako pa tudi zdravstvenega osebja. Različne površine v bolnišničnem okolju lahko tudi pripomorejo k razširitvi mikroorganizmov. Dokazano je, da so mikroorganizmi sposobni preživeti na površinah tudi do nekaj tednov.
Metodologija: V raziskavi smo vzorčili predhodno kontaminirane kovinske, steklene in plastične površine in jemali brise le-teh po 24-urnem sušenju. Izbrani mikroorganizmi so bili: E. faecium, S. aureus, B. subtilis, E. coli, K. pneumoniae, P. aeruginosa in C. albicans. Iz brisov smo eluirali mikroorganizme s fiziološko raztopino. Iz eluata smo najprej določili koncentracijo mikroorganizmov s klasično mikrobiološko metodo z nanosom na selektivne medije. Z metodo PCR smo nato določili še prisotnost DNK izbranih mikroorganizmov. Za statistično analizo smo uporabili programsko orodje IBM SPSS 20. Z neparametričnima testoma smo ugotavljali statistično pomembne razlike.
Rezultati: Z molekularno metodo smo rezultat dobili v nekaj urah, s klasično inkubacijsko metodo je trajalo 2–3 dni. Ko smo primerjali preživetje izbranih mikroorganizmov pri različnih koncentracijah na kovinski in stekleni površini, nismo opazili statistično značilnih razlik, saj je bil p ≥ 0,05. Ko pa smo zajeli še plastično površino, so se razlike pokazale pri po Gramu pozitivnima bakterijama E. faecium in S. aureus ter po Gramu negativnima bakterijama E. coli in P. aeruginosa, saj je bil p ≤ 0,05.
Sklep: Klasična gojitvena metoda je dolgotrajna, medtem ko se metoda PCR lahko uporablja za hitro oceno čistoče površin, saj smo v nekaj urah prišli do rezultatov.
Keywords: bolnišnične okužbe, detekcija, površine, PCR, Enterococcus faecium, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans.
Published in DKUM: 15.06.2015; Views: 2455; Downloads: 199
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10. PRIMERJAVA KLASIČNE GOJITVENE METODE NA SELEKTIVNIH AGARNIH GOJIŠČIH IN MOLEKULARNE METODE VERIŽNE REAKCIJE S POLIMERAZO ZA ANALIZO UMETNO KONTAMINIRANIH TEKSTILIJDunja Pahor, 2015, master's thesis Abstract: Izhodišča: Kljub napredku na področju javnega zdravja in bolnišnične oskrbe, so bolnišnične okužbe pri hospitaliziranih bolnikih zelo pogost pojav. Izvor bolnišničnih okužb so lahko obiskovalci, zdravstveno osebje, bolniki, bolnikova okolica s kontaminiranimi predmeti in površinami. Eden izmed vektorjev prenosa mikroorganizmov in s tem bolnišničnih okužb so lahko tudi kontaminirane tekstilije, ki jih uporabljajo hospitalizirani bolniki (brisače, odeje, rjuhe, osebna oblačila). S postopki detekcije in identifikacije mikroorganizmov na tekstilijah lahko ocenimo stopnjo kakovosti higiene bolnišničnih tekstilij. To je zadosten razlog za iskanje optimalnih rešitev detekcije in identifikacije mikroorganizmov, ki morajo biti hitre, dostopne in cenovno ugodne.
Metodologija: V raziskavi smo tekstilne krpice iz 100 % bombaža umetno kontaminirali z Gram-pozitivnima bakterijama E. faecium in S. aureus ter Gram-negativno bakterijo E. coli. Tekstilne krpice, kontaminirane z mikroorganizmi smo hranili 21 dni pri 5 ˚C, 25 ˚C in 50 ˚C. Vzorčili smo z aparatom Morapex A z nedestruktivno metodo eluiranja. V raziskavi smo ugotavljali, kako izpostavljenost bakterij daljšemu sušenju vpliva na preživetje le-teh in kako začetna koncentracija izbranih bakterij vpliva na delež preživelih bakterij glede na čas. Primerjali smo učinkovitost klasičnih gojitvenih metod na selektivnih agarnih gojiščih in učinkovitost molekularnih metod verižne reakcije s polimerazo pri identifikaciji izbranih vzorcev.
Rezultati: Raziskava je pokazala, da je molekularna metoda na osnovi verižne reakcije s polimerazo občutljivejša metoda identifikacije DNA. Ugotovili smo, da izpostavljenost bakterij na umetno kontaminiranih tekstilijah daljšemu sušenju vpliva na preživetje bakterij ter da se število preživelih bakterij s časom zmanjšuje. Različne koncentracije izbranih bakterij na umetno kontaminiranih tekstilijah vplivajo na delež preživelih bakterij v času.
Sklep: V raziskavi smo pokazali preživetje mikroorganizmov na tekstilijah pri različnih pogojih (čas, temperatura in koncentracija) pri čemer se je PCR metoda pokazala kot bolj občutljiva metoda identifikacije.
Keywords: Bolnišnične okužbe, detekcija, tekstilije, PCR, Enterococcus faecium, Staphylococcus aureus, Escherichia coli.
Published in DKUM: 12.06.2015; Views: 27279; Downloads: 160
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