1,721,037 research outputs found
Virulence factors of the bacteria enterococcus faecium from different isolation sources
No full textBakterija Enterococcus faecium je komenzalni organizmi u mikrobioti probavnog sustava čovjeka, ali ih
nalazimo i u okolišu, tlu, vodama, hrani, biljkama i životinjama. Ovi koki smatraju se i oportunističkim
patogenima jer mogu uzorkovati razne infekcije u čovjeka. Cilj ovog rada je ispitati osjetljivost prikupljenih
bakterijskih sojeva E. faecium na antimikrobni lijek vankomicin te ispitati slijedeće virulentne čimbenike;
stvaranje biofilma, β-hemolitičku aktivnost te hidrofobnost stanične površine. Prikupljeno je 90 sojeva
bakterije Enterococcus faecium iz tri različita izvora; klinički uzorci iz bolničke sredine, hrana te otpadne
vode. Iz svakog izvora uzeto je 30 sojeva. Ispitivanjem osjetljivosti sojeva na antibiotik vankomicin utvrđeno
je da je najveći broj rezistentnih sojeva prikupljeno iz bolničke sredine, a ispitivanjem sposobnosti stvaranja
biofilma pokazalo se da su sojevi izolirani iz bolnice i hrane značajno bolji produktori biofilma od sojeva
izoliranih iz otpadnih voda. Također, utvrđeno je da izolati iz hrane imaju najveću hidrofobnost stanične
površine, a ispitivanjem β-hemolitičke aktivnosti 90 sojeva utvrđeno je da su svega šest soja β-hemolitički
aktivna; tri izolata iz hrane, dva iz bolnice te jedan iz otpadnih voda. U ispitivanih sojeva rezistentnih na
vankomicin (VRE) nije uočena korelacija virulentnih čimbenika hidrofobnosti stanične površine i stvaranja
biofilma u uvjetima in vitro. Međutim, ispitivanje je provedeno na malom uzorku sojeva VRE te se ne može
izvući opći zaključak moguće korelacije. Iz dobivenih se podataka može zaključiti da postoji razlika u
virulentnim čimbenicima između izoliranih sojeva bakterije E. faecium, stoga se početna hipoteza pokazala
točnom.The bacterium Enterococcus faecium is a commensal organism in the microbiota of the human digestive
system, but we also find it in the environment, soil, water, food, plants and animals. These cocci are also
considered opportunistic pathogens because they can sample various infections in humans. The aim of this
study is to test the sensitivity of the collected bacterial strains of E. faecium to the antimicrobial drug
vancomycin and to test the following virulence factors; biofilm formation, β-hemolytic activity and
hydrophobicity of the cell surface. 90 strains of Enterococcus faecium bacteria were collected from three
different sources; clinical samples from the hospital environment, food and waste water. 30 strains were taken
from each source. Testing the sensitivity of the strains to the antibiotic vancomycin showed that the largest
number of resistant strains were collected from the hospital environment and testing the ability to form
biofilms showed that strains isolated from hospitals and food are significantly better biofilm producers than
strains isolated from wastewater. Also, it was determined that isolates from food have the highest
hydrophobicity of the cell surface and testing the β-hemolytic activity of 90 strains revealed that only six
strains are β-hemolytically active; three isolates from food, two from the hospital and one from waste water.
From the examined vancomycin-resistant (VRE) strains, no correlation was observed between the virulence
factors of cell surface hydrophobicity and biofilm formation under in vitro conditions. However, the test was
conducted on a small sample of VRE strains and a general conclusion of a possible correlation cannot be
drawn. From the obtained data, it can be concluded that there is a difference in virulence factors between the
isolated strains of E. faecium bacteria, therefore the initial hypothesis proved to be correct
Inhibition of Candida albicans virulation factors with oleuropein and hydroxytyrosol
Full text linkCandida albicans je dio ljudskog mikrobioma (endogeni oportunistički kvasac koji u zdravih osoba ne uzrokuje infekciju). No, narušavanjem ravnoteže između mikrobioma i nositelja, komenzalni oblik prelazi u infekciju s kliničkom manifestacijom. Cilj ovoga rada je utvrditi učinak oleuropeina i hidroksitirosola te njihov menhanizam djelovanja na vrstu Candida albicans. Određivanjem ergosterola SQM metodom utvrđeno je da oleuropein i hidroksitirosol u sub-MIK vrijednostima nakon 18 sati inkubacije na 35°C daju rezultate koji pokazuju njegovo uplitanje u put biosinteze ergosterola. Određivanjem učinka hidroksitirosola i oleuropeina na inhibiciju germinacije blastospora vrste C. albicans pokazalo se oleuropein i hidroksitirosol nakon 3 sata inkubacije na 37 °C inhibiraju germinaciju blastospora već u sub-MIK koncentracijama djelovanjem na unutarstanične signalne puteve (cAMP-PKA). Ispitivanjem učinka na rast filamenata otkriveno je da oleuropein i hidroksitirosol nakon 3 sata inkubacije na 37 °C inhibiraju rast filamenata germiniranih stanica vrste C. albicans već u sub-MIK koncentracijama. Iz dobivenih se podataka može zaključiti da su oleuropein i hidroksitirosol izrazito zanimljive molekule za daljnja istraživanja mehanizama antifungalnog učinka, ali i mogućeg sinergističkog učinka s antimikoticima. Prema tome, potrebna su daljnja istraživanja mehanizama djelovanja na faktore virulencije.Candida albicans is an endogenous opportunistic yeast that does not cause infections in healthy individuals. However, disruption of the balance between microbiome and microorganism, the commensal form becomes pathogenic with clinical manifestation. The aim ofthis study was to determine the effect of oleuropein and hydroxytyrosol and their mechanism of action in C. albicans in vitro. Using the SQM approach for modulation ofergosterol synthesiswe found that oleuropein and hydroxytyrosol in concentrations below the MIC after 18 hours of incubation at 35 °C showed their interference in ergosterol biosynthesis pathway. The testing of the effect of hydroxytrosol and oleuropein on the inhibition of blastospore germination of C. albicans showed that after 3 hours of incubation at 37 °C oleuropein and hydroxytyrosol inhibit the germination even in values below MIC affecting the cellular signal pathways (cAMP-PKA). The testing of inhibition of growth of filaments reveals that oleuropein and hydroxytyrosol after 3 hours of incubation at 37 °C inhibit the growth of filaments of C. albicans germinated cells even in sub-MIC concentrations. Oleuropein and hydroxytyrosol are extremely interesting molecules for further research into mechanisms of antifungal activity, but also for possible synergistic effect with antimycotics. Therefore, further research into mechanisms of action on virulence factors is required
Virulence factors of the bacterium Enterococcus faecalis from different isolation sources
No full textBakterija Enterococcus faecalis je oportunistički patogen, poznata po komenzalističkom životu kao dio mikrobiote
različitih organskih sustava, a nalazi se i u okolišu. Uzrokuje infekcije urinarnog sustava, inficira kože i rane, a također
je specifična kao uzročnik endokarditisa. Sadrži mnoge virulentne čimbenike, a u ovom radu su detaljnije obrađeni
hidrofobnost stanične površine, sposobnost stvaranja biofilma, β-hemolitička aktivnost te osjetljivost na vankomicin.
Cilj diplomskog rada je bio utvrditi postoje li značajne razlike u uvjetima in vitro u virulenciji sojeva E. faecalis
izoliranih iz bolnice, hrane i otpadnih voda nakon statističke obrade rezultata. Istraživanjem hidrofobnosti stanične
površine zaključuje se da sojevi izolirani iz hrane imaju najveću hidrofobnost, dok između bolničkih izolata i onih iz
otpadnih voda nije bilo značajne razlike. Prema metodi iz rada Stępień-Pyśniak (2019), sposobnost stvaranja biofilma
je podijeljena u četiri kategorije te su sojevi iz bolničkog izvora najjači produktori biofilma, zatim sojevi iz hrane i
sojevi iz otpadnih voda kao najslabiji produktori biofilma. Ako se gleda sposobnost stvaranja biofilma samo prema
izmjerenoj optičkoj gustoći sojeva, najjači produktori biofilma su sojevi iz hrane potom iz otpadnih voda i konačno
bolnički izolati. Hemoliza je utvrđena u 20,00% sojeva iz bolničkog izvora, 16,67% iz hrane te 26,67% iz otpadnih
voda pri čemu Bonfferonijev test ukazuje da razlike između rezultata različitih sojeva nisu statistički značajne. Od
ukupno 30 sojeva iz svakog izvora, rezistenciju na vankomicin iz bolničkog izvora je pokazalo 10,00%, iz hrane 3,33%
i iz otpadnih voda 20,00%. Može se zaključiti da se nakon provedenih ispitivanja nulta hipoteza pokazala točnom kod
svih virulentnih čimbenika osim hemolize.The bacterium Enterococcus faecalis is an opportunistic pathogen known for its commensal life as part of the microbiota
of various organic systems and it can also be found in the environment. It causes infections of the urinary system, infects
skin and wounds, and is also a specific cause of endocarditis. It holds many virulent factors, of which the hydrophobicity
of the cell surface, the ability to form biofilm, β-hemolytic activity and susceptibility to vancomycin are discussed in
more detail in this paper. The aim of the thesis was to determine whether there are significant differences in in vitro
conditions the virulence of E. faecalis strains isolated from the hospital, food and wastewater after statistical data
processing. By investigating the hydrophobicity of the cell surface, it was concluded that the strains isolated from food
have the highest hydrophobicity, while there was no significant difference between hospital isolates and those from
wastewater. According to the method from the work of Stępień-Pyśniak (2019), the ability to form biofilm is divided
into four categories and those isolated from a hospital source are the strongest biofilm producers followed by strains
from food and strains from wastewater as the weakest biofilm producers. If the ability to form a biofilm is viewed only
according to the measured optical density of the strains, the strongest biofilm producers are strains isolated from food,
followed by isolates from wastewater and finally hospital isolates. Hemolysis was shown by 20,00% of strains from a
hospital source, 16,67% from food and 26,67% from wastewater, while the Bonfferoni test indicates that the differences
between the results of different strains are not statistically significant. Out of a total of thirty strains from each source,
10,00% showed resistance to vancomycin from a hospital source, 3,33% from food and 20,00% from wastewater. It can
be concluded that after the conducted tests, the null hypothesis proved to be correct for all virulence factors except
hemolytic activity
Clinical utilization of colistin: a review of current clinical guidelines and research aiming to increase its clinical lifespan
No full textKolistin (polimiksin E) je ciklički kationski lipodekapeptidni antibiotik čiji mehanizam djelovanja
uključuje narušavanje integriteta stanične membrane gram-negativnih bakterija. Kolistin je u
kliničku praksu ušao sredinom 20. stoljeća, no njegova je primjena zbog nefrotoksičnosti i
neurotoksičnosti napuštena već desetak godina nakon uvođenja u kliniku. U današnje vrijeme AMR
postaje rastući zdravstveni problem zbog kojeg ponestaje terapijskih opcija za liječenje životno
ugrožavajućih infekcija. Zato je kolistin pronašao svoje mjesto u klinici kao rezervni antibiotik s
obzirom na to da je trenutno stopa rezistencije na kolistin relativno niska. S obzirom na to da je
kolistin u humanoj medicini dugo bio opsolentan tek su 2019. godine donesene kliničke smjernice
za uporabu kolistina koje su konsenzus relevantnih svjetskih kliničkih društava. Iz literature je uočen
je trend porasta potrošnje kolistina u bolničkim sredinama u RH u periodu od 2011.-2021. Stoga
zabrinjava i mogućnost porasta stope rezistencije na kolistin u bliskoj budućnosti. Kako bi se očuvala
klinička efikasnost kolistina trenutno se razvijaju brze dijagnostičke metode za rano otkrivanje
rezistencije na kolistin te se istražuju potencijalni adjuvantni terapeutici za kolistin.Colistin (polymyxin E) is a cyclic cationic lipodecapeptide antibiotic. Its mechanism of action
involves the disruption of the cellular membrane of Gram-negative bacteria. Colistin has been
discovered in 1947. Due to its high nephrotoxicity and neurotoxicity, its clinical use has been
abandoned already a decade after its discovery. AMR is a growing public health issue, as there are
currently few therapeutic options for treating life-threatening infections. Colistin has recently been
re-introduced for clinical use due to its low resistance rates at the moment. In 2019., the first
consensus clinical guidelines among relevant global clinical societies have been published.
Literature has shown an increase in the clinical use of colistin in Croatian hospitals over the period
2011.-2021. Therefore, it is concerning that colistin resistance rates might increase over the
following years. To increase colistin’s clinical lifespan, researchers are developing diagnostic
methods for early resistance diagnostics and searching for potential adjuvant therapeutics for
colistin
D-mannose in the prevention of uncomplicated recurrent outhospital cystitis in women of reproductive age - level of evidence
No full textU suvremenoj medicini, infekcije mokraćnog sustava i dalje predstavljaju iznimno velik ekonomski i socijalni teret na zdravstveni sustav, a nerazumnim propisivanjem antibiotika pridonosi se povećanju antibiotske rezistencije kao i smanjenju njihove učinkovitosti, što također predstavlja jedan od najvećih problema suvremene medicine. Uzimajući u obzir sve te podatke, možemo zaključiti da budućnost liječenja i profilakse infekcija mokraćnog sustava kod osoba ženskog spola, koje od istih i puno češće obolijevaju, moramo potražiti u učinkovitim alternativnim metodama, odnosno zamjenama za antibiotike. Nadalje, u smjernicama Europskog urološkog društva, najmanje je riječi i dokaza o učinku D-manoze što je ujedno i obraloženje odabira navedene teme. Pretragom literaturnih podataka i studija o učinkovitosti D-manoze kao monoterapije u liječenju i prevenciji rekurentnih IMS kod žena reproduktivne dobi, može se zaključiti da je D-manoza učinkovita kako u liječenju, tako i u prevenciji od ponovnih epizoda infekcija mokraćnog sustava, odnosno nekompliciranih cistitisa. Obzirom da je, za daljnje zaključke i potvrde s visokim razinama dokaza, potrebno provesti više preciznijih studija s većim brojem ispitanica, D-manoza se još uvijek vodi kao dodatak prehrani i za sada nema registriranih lijekova na bazi D-manoze, što je upitno sa strane kakvoće same tvari. Za temu ovog diplomskog rada pretražene su baze WoSCC i Scopus prema prilagođenim PRISMA smjernicama te su nakon probira studija koje obuhvaćaju temu ovog rada, studije opisane kroz PICO kriterije. Prema radnoj grupi GRADE, sve probrane studije korištene u evaluaciji dokaza D-manoze za ciljanu skupinu ispitanica isključivo su mala randomizirana ispitivanja s nižom metodološkom kvalitetom, stoga bi se razina dokaza D-manoze svrstala u skupinu II popisanih razina dokaza radne skupine GRADE. Zaključno, pacijente je potrebno educirati o upotrebi učinkovitih alternativnih metoda liječenja kojima bi se smanjila nerazumna potrošnja antibiotika i povećala svijest pacijenata o problemu antibiotske rezistencije. Upravo u tome svemu najveću ulogu može imati ljekarnik kao najdostupniji zdravstveni djelatnik koji bi na temelju znanstveno točnih i utvrđenih podataka, educirao građanke i građane o pravilnoj upotrebi terapije i razumnom pristupu liječenju.In modern medicine, urinary tract infections (UTIs) continue to represent an extremely large economic and social burden on the health system, and the unreasonable prescription of antibiotics contributes to the increase of antibiotic resistance as well as to the reduction of their effectiveness, which is also one of the biggest problems of modern medicine. Considering all these data, we can conclude that the future of treatment and prophylaxis of urinary tract infections in women, who suffer from them much more often, must be found in effective alternative methods, i.e., substitutes for antibiotics. Furthermore, in the guidelines of the European Urological Society, there are only few words or evidence about the effect of D-mannose, which is also the main reason of choosing this topic. By searching literature data and studies on the effectiveness of D-mannose as monotherapy in the treatment and prevention of recurrent UTIs in women of reproductive age, it can be concluded that D-mannose is effective both in the treatment and in the prevention of repeated episodes of urinary tract infections, i.e., uncomplicated cystitis. Considering that, for further conclusions and confirmations with high levels of evidence, it is necessary to conduct more precise studies with a larger number of subjects, D-mannose is still used as a dietary supplement and for now there are no registered medicines based on D-mannose, which presents the questionable side of the quality of the substance itself. For the topic of this thesis, the WoSCC and Scopus databases were searched according to the adjusted PRISMA guidelines, and after selecting the studies that cover the topic of this thesis, the studies were described using the PICO criteria. According to the GRADE working group, all the selected studies used in the evaluation of the evidence of D-mannose for the target group of subjects are exclusively small, randomized trials with lower methodological quality, therefore the level of evidence of D-mannose would be classified in group II of the listed levels of evidence of the GRADE working group. In conclusion, patients need to be educated about the use of effective alternative treatment methods that would reduce the unreasonable consumption of antibiotics and increase patients' awareness of the problem of antibiotic resistance. In solving all the mentioned problems, the greatest role can be played by the pharmacist as the most accessible healthcare worker who, based on scientifically accurate and established data, would educate citizens about the correct use of therapy and a reasonable approach to treatment
Clinical utilization of colistin: a review of current clinical guidelines and research aiming to increase its clinical lifespan
No full textKolistin (polimiksin E) je ciklički kationski lipodekapeptidni antibiotik čiji mehanizam djelovanja
uključuje narušavanje integriteta stanične membrane gram-negativnih bakterija. Kolistin je u
kliničku praksu ušao sredinom 20. stoljeća, no njegova je primjena zbog nefrotoksičnosti i
neurotoksičnosti napuštena već desetak godina nakon uvođenja u kliniku. U današnje vrijeme AMR
postaje rastući zdravstveni problem zbog kojeg ponestaje terapijskih opcija za liječenje životno
ugrožavajućih infekcija. Zato je kolistin pronašao svoje mjesto u klinici kao rezervni antibiotik s
obzirom na to da je trenutno stopa rezistencije na kolistin relativno niska. S obzirom na to da je
kolistin u humanoj medicini dugo bio opsolentan tek su 2019. godine donesene kliničke smjernice
za uporabu kolistina koje su konsenzus relevantnih svjetskih kliničkih društava. Iz literature je uočen
je trend porasta potrošnje kolistina u bolničkim sredinama u RH u periodu od 2011.-2021. Stoga
zabrinjava i mogućnost porasta stope rezistencije na kolistin u bliskoj budućnosti. Kako bi se očuvala
klinička efikasnost kolistina trenutno se razvijaju brze dijagnostičke metode za rano otkrivanje
rezistencije na kolistin te se istražuju potencijalni adjuvantni terapeutici za kolistin.Colistin (polymyxin E) is a cyclic cationic lipodecapeptide antibiotic. Its mechanism of action
involves the disruption of the cellular membrane of Gram-negative bacteria. Colistin has been
discovered in 1947. Due to its high nephrotoxicity and neurotoxicity, its clinical use has been
abandoned already a decade after its discovery. AMR is a growing public health issue, as there are
currently few therapeutic options for treating life-threatening infections. Colistin has recently been
re-introduced for clinical use due to its low resistance rates at the moment. In 2019., the first
consensus clinical guidelines among relevant global clinical societies have been published.
Literature has shown an increase in the clinical use of colistin in Croatian hospitals over the period
2011.-2021. Therefore, it is concerning that colistin resistance rates might increase over the
following years. To increase colistin’s clinical lifespan, researchers are developing diagnostic
methods for early resistance diagnostics and searching for potential adjuvant therapeutics for
colistin
The In Virto Antimicrobial Activity of Satureja montana L., S. subspicata Vis., Eryngium alpinum L. and E. amethystinum L.
No full textU svrhu upoznavanja bioloških učinaka tvari biljnog porijekla na čovjeka, posebice biljaka samoniklih na tlu RH roda Satureja L. (S. montana L. i S. subspicata Vis.) i Eryngium L. ( E. alpinum L. i E. amethystinum L.), cilj ovog istraživanja je bio utvrditi spektar antimikrobnih učinaka metanolnih ekstrakata navedenih biljnih vrsta metodom mikrodilucije (određivanje minimalne inhibitorne koncentracije - MIK), te istražiti inhibirajuće djelovanje ekstrakata na germinaciju blastospora gljivice Candida albicans. Ekstrakti biljke S. montana su pokazali najbolju antimikrobnu aktivnost na Staphylococcus aureus i Candida albicans (MIK=3,6 μg/ml), a S. subspicata Vis. na C. krusei (MIK= 10,9 μg/ml). Izražene su razlike u djelovanju ekstrakata obiju vrsta s obzirom na različite lokacije sabiranja biljaka. Ekstrakti E. alpinum djelovali su na C. dubliniensis sa vrijednošću MIK= 13,7 μg/ml, kao i E. amethystinum. Ekstrakti Satureja L. pokazuju značajno inhibitorno djelovanje na germinaciju blastospora C. albicans 37% u koncentraciji 30 μg/ml, a vrste roda Eryngium L. u koncentraciji 300 μg/ml 36%.In order to introduce the biological effects of substances of plant origin on humans, especially wild plants on the soil of Croatia with regard to genus Satureja L. (S. montana L. and S. subspicata Vis.) and Eryngium L. ( E. alpinum L. and E. amethystinum L.), the aim of this study was to determine the spectrum of antimicrobial effects of methanol extracts of plant species with microdilution method (to determine minimal inhibitory concentration- MIC), and to investigate whether some extracts inhibited the germination of blastospores of Candida albicans. Extracts of S. montana showed the best antimicrobial activity against Staphylococcus aureus and Candida albicans (MIC=3,6 μg/ml), and S. subspicata Vis. against C. krusei (MIC= 10,9 μg/ml). There are significant differences in the activity within extracts from various locations where plants were collected. Extracts of E. alpinum affect on C. dubliniensis with MIC=13,7 μg/ml, as well as E. amethystinum. Extracts of Satureja L. showed significantly inhibitory effect on germination of blastospores of C. albicans more then 37% in concentration 30 μg/ml, and species of genus Eryngium L. in concentration 300 μg/ml 36%
Antimicrobial effect of colloid solutions of nanoparticles of elementary metals and metallic oxides on MSSA and MRSA
Full text linkSmanjivanjem veličine čestica vrlo često se mijenjaju fizikalno-kemijska svojstva, pogotovo ako se veličina čestica smanji na dimenzije ispod 1 μm. Smanjivanjem veličine čestica ispod 1 μm otvara se mogućnost pronalaska novih biološki aktivnih tvari. Jedne od takvih biološki aktivnih tvari su nanočestice metala i metalnih oksida (MNP), te je cilj ovog rada istražiti antimikrobna svojstva MNP u koloidnom obliku. Koloidni MNP pokazuju vrijednosti minimalne baktericidne (MBK) i inhibitorne (MIK) koncentracije u rasponima od 0,01 do 100 ppm-a. Najniže MIK i MBK vrijednosti pokazuju nanočestica koloidnog ZnO, dok najviše pokazuju nanočestice koloidnog TiO2, međutim koloidne nanočestice ZrO2 pokazuju bakteriostatski učinak u cijelom rasponu ispitivanih koncentracija, dok baktericidni učinak izostaje. Pokazano je da i antimikrobnu učinkovitost koloida Ag mogu smanjivati kompleksni mediji, kao što su serum te otopine proteina. Iako MNP djeluju uglavnom na nespecifičan način, preko tvorbe reaktivnih kisikovih vrsta (ROS) i penetracija membrane, odnosno stijenke, postoje značajne razlike među meticilin-rezistentnom (MRSA) i meticilin-osjetljivom (MSSA) soju vrste Staphylococcus aureus. Sinergizam nanočestica se ispitivao putem indeksa frakcionarne baktericidne (FBKI), odnosno inhibitorne (FIKI) koncentracije, te tako kombinacije koloidnog Ag, ZnO, i TiO2, na soju MRSA pokazuju sinergistički, a na soju MSSA antagonistički učinak. U svrhu ispitivanja praktične primjene MNP, tkanina od 1cm2 impregnirala se slojem smjese koloida MNP te se ispitivala njena antimikrobna učinkovitost u vremenu pomoću „time-kill“ metode. Potpuna redukcija vijabilnih bakterija soja MSSA i MRSA postignuta je nakon 18 sati, s time da je redukcija soja MRSA brža nego soja MSSA.Reducing the size of particles results in different physical and chemical properties, especially if the size is reduced below 1 μm. Reducing the size of particles below 1 μm opens up the possibility of finding new biologically active compounds. One of such biologically active compunds are nanoparticles of metals and metalic oxides (MNP), and therefore it is the cause of this paper to explore antimicrobial properties of MNP in colloid form. Colloid MNP show minimal bactericidal (MBC) and inhibitory (MIC) concentrations in ranges of 0,01 to 100 ppm. Lowest MIC and MBC values belong to colloid NP of ZnO, while highest values belong to colloid TiO2, however, colloid nanoparticles of ZrO2 demonstrate bacteriostatic effect in the entire range of tested concentrations, while bactericidal effect is absent. It has also been shown that antimicrobial efficacy of colloid Ag can be reduced by complex mediums, such as serum and protein solutions. Although MNP act through unspecific pathways, such as generations of reactive oxygen species (ROS) and penetration of cell membrane and wall, there are significant differences between methicillin-resistent (MRSA) and methicillin-sensitive (MSSA) strains of Staphyloccocus aureus. Synergism of nanoparticles was tested through fractionary bactericidal (FBCI) and inhibitory (FICI) concentration index, and combinations of colloid Ag, ZnO, and TiO2 show synergystic effect on MRSA, and antagonistic effect on MSSA. In the effort to test practical usage of MNP, a fabric of 1cm2 was impregnated with a layer of mixture of colloid MNP, and had its antimicrobial efficacy in time tested using „time-kill“ assay. Complete reduction of viable bacteria of strains MSSA and MRSA was achieved after 18 hours, with the fact that reduction of MRSA strain was faster than MSSA strain
Modulacija mikrobioma kože
No full textKoža je fizička barijera, ali ujedno posjeduje kemijski i imunološke definirane obrambene sposobnosti. Na njoj se također nalaze i mikrobiote. Izuzev dobro proučavanih mikrobnih zajednica, kao što su gastrointestinalni sustav i rodnica, mikrobiom kože također je zanimljiv za znanstvena istraživanja. U ovome radu diskutirat će se o mikrobiomu kože, rasprostranjenosti mikrobiota na koži (bakterija, arheja i eukariotskih stanica) i o njihovoj ulozi u eubiozi. Diskusija će se posebice fokusirati na mikrobiotama pazušne jame i njihovoj ulozi tvorbe (neugodnog) mirisa tijela u cilju smanjenja tog mirisa. S druge strane, objasnit će se primjena antiseptika (kao biocida) na koži ruku u cilju smanjenja mikrobne populacije (stalne ili povremene), kao i velike uloge pranja ruku u javnom zdravstvu.The skin as an organ is a physical barrier but it also has chemically and immunologically defined defensive properties. Skin also harbors microbiota. Besides the widely studied microbial communities such as the gastro-intestinal tract and the vaginal epithelia, the skin microbiome is also an interesting target of scientific research. In this thesis we shall discuss skin microbiome properties, the diversity of microbiota on the skin (bacteria, archaea and eukaryotic cells) and their role in eubiosis. The discussion will be especially focused on explaining the diversity of microbiota in the armpit (axillae) and their role in the occurrence of unpleasant body odor with the goal of reducing that odor. The next focus of the present thesis will be on the use of antiseptics (as biocides) on the skin of the hands with the goal of reducing the microbial population (resident or transient) as well as the major role of washing hands in public health. Taking into account resident and transient microbiota on the skin of the hands, the use of antiseptics has a major impact on the spreading of multiple-resistant microbial species via hands, which is an important public health issue
Virulence factors of the bacterium Enterococcus faecalis from different isolation sources
No full textBakterija Enterococcus faecalis je oportunistički patogen, poznata po komenzalističkom životu kao dio mikrobiote
različitih organskih sustava, a nalazi se i u okolišu. Uzrokuje infekcije urinarnog sustava, inficira kože i rane, a također
je specifična kao uzročnik endokarditisa. Sadrži mnoge virulentne čimbenike, a u ovom radu su detaljnije obrađeni
hidrofobnost stanične površine, sposobnost stvaranja biofilma, β-hemolitička aktivnost te osjetljivost na vankomicin.
Cilj diplomskog rada je bio utvrditi postoje li značajne razlike u uvjetima in vitro u virulenciji sojeva E. faecalis
izoliranih iz bolnice, hrane i otpadnih voda nakon statističke obrade rezultata. Istraživanjem hidrofobnosti stanične
površine zaključuje se da sojevi izolirani iz hrane imaju najveću hidrofobnost, dok između bolničkih izolata i onih iz
otpadnih voda nije bilo značajne razlike. Prema metodi iz rada Stępień-Pyśniak (2019), sposobnost stvaranja biofilma
je podijeljena u četiri kategorije te su sojevi iz bolničkog izvora najjači produktori biofilma, zatim sojevi iz hrane i
sojevi iz otpadnih voda kao najslabiji produktori biofilma. Ako se gleda sposobnost stvaranja biofilma samo prema
izmjerenoj optičkoj gustoći sojeva, najjači produktori biofilma su sojevi iz hrane potom iz otpadnih voda i konačno
bolnički izolati. Hemoliza je utvrđena u 20,00% sojeva iz bolničkog izvora, 16,67% iz hrane te 26,67% iz otpadnih
voda pri čemu Bonfferonijev test ukazuje da razlike između rezultata različitih sojeva nisu statistički značajne. Od
ukupno 30 sojeva iz svakog izvora, rezistenciju na vankomicin iz bolničkog izvora je pokazalo 10,00%, iz hrane 3,33%
i iz otpadnih voda 20,00%. Može se zaključiti da se nakon provedenih ispitivanja nulta hipoteza pokazala točnom kod
svih virulentnih čimbenika osim hemolize.The bacterium Enterococcus faecalis is an opportunistic pathogen known for its commensal life as part of the microbiota
of various organic systems and it can also be found in the environment. It causes infections of the urinary system, infects
skin and wounds, and is also a specific cause of endocarditis. It holds many virulent factors, of which the hydrophobicity
of the cell surface, the ability to form biofilm, β-hemolytic activity and susceptibility to vancomycin are discussed in
more detail in this paper. The aim of the thesis was to determine whether there are significant differences in in vitro
conditions the virulence of E. faecalis strains isolated from the hospital, food and wastewater after statistical data
processing. By investigating the hydrophobicity of the cell surface, it was concluded that the strains isolated from food
have the highest hydrophobicity, while there was no significant difference between hospital isolates and those from
wastewater. According to the method from the work of Stępień-Pyśniak (2019), the ability to form biofilm is divided
into four categories and those isolated from a hospital source are the strongest biofilm producers followed by strains
from food and strains from wastewater as the weakest biofilm producers. If the ability to form a biofilm is viewed only
according to the measured optical density of the strains, the strongest biofilm producers are strains isolated from food,
followed by isolates from wastewater and finally hospital isolates. Hemolysis was shown by 20,00% of strains from a
hospital source, 16,67% from food and 26,67% from wastewater, while the Bonfferoni test indicates that the differences
between the results of different strains are not statistically significant. Out of a total of thirty strains from each source,
10,00% showed resistance to vancomycin from a hospital source, 3,33% from food and 20,00% from wastewater. It can
be concluded that after the conducted tests, the null hypothesis proved to be correct for all virulence factors except
hemolytic activity
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