The study was carried out with the aim of establishing how the outcomes of polyelectrolyte multil... more The study was carried out with the aim of establishing how the outcomes of polyelectrolyte multilayer formation can be predicted on the basis of the results of complexation studies in solution and vice versa.
International Journal of Environmental Health Research, Dec 12, 2017
The aim of this study was to analyze the impact of hydrodynamic forces on the multiplication of E... more The aim of this study was to analyze the impact of hydrodynamic forces on the multiplication of E. coli, and biofilm formation and dispersion. The experiments were provided in a flow chamber simulating a cleaning-in-place system. Biofilm biomass was measured using a crystal violet dye method. The results show that hydrodynamic forces affect not only biofilm formation and dispersion but the multiplication of E. coli in the first place. We found more biofilm biomass on the rough surface than on the smooth one. The results of the biofilm formation test show that laminar flow promotes the biofilm growth over 72 h, meanwhile turbulent flow after 48 h causes decrease in biomass. The results of the biofilm dispersion test, in contrast, show that laminar flow removed less biofilm from both materials that turbulent flow did. Therefore, taking into account these findings in cleaning-in-place technology can substantially reduce E. coli multiplication and biofilm formation.
V primeru naravnih ali drugih nesreč lahko v zelo kratkem času nastopijo izredne razmere, ki ne o... more V primeru naravnih ali drugih nesreč lahko v zelo kratkem času nastopijo izredne razmere, ki ne ogrožajo le posameznika, ampak tudi širšo skupnost. Poleg izgube človeških življenj in večjega števila poškodovanih nastane tudi velika materialna škoda. Porušeni domovi, oslabljena infrastruktura, prekinjena dobava električne energije in vode pripeljejo do razmer, ko si prizadeto prebivalstvo ne more samo zagotoviti osnovnih življenjskih pogojev in je odvisno od pomoči različnih humanitarnih organizacij. Ena takšnih je tudi mednarodna organizacija Rdečega križa, ki ima usposobljene ekipe za ukrepanje v izrednih razmerah. Člani teh ekip so usposobljeni za pridobivanje pitne vode, gradnjo začasnih bivališč in sanitarij, izvajanje dezinfekcije, dezinsekcije in deratizacije, pomagajo pri oskrbi z živilskimi in neživilskimi proizvodi, promociji higiene in drugo. V okviru mednarodnega projekta XH2O se je za zagotavljanje pitne vode v izrednih razmerah usposobilo 15 strokovnjakov iz Slovenije, ...
Workers spend a lot of time at work, and therefore, it is important to ensure healthy workplaces.... more Workers spend a lot of time at work, and therefore, it is important to ensure healthy workplaces. The aim of this study was to evaluate the ergonomic strains of accountants and suggest measures to overcome the work-related overload and improve the working conditions. We monitored the work of three accountants through the Ovako Working posture Assessment System (OWAS) methodology and measured the microclimate and lighting conditions. The results of microclimate conditions show that the room temperature was 26 °C, the humidity was 47 %, and the airflow 0.11 ms-1. The results of the OWAS methodology gave us insights into the overload of the spine and the upper and lower limbs. In most cases, corrective measures are needed. Immediate measures need to be implemented for the upper limb load for all the observed subjects, while arm load needs to be further researched. Our findings could reduce the work-related discomforts if workers and employers followed our recommendations
International Journal of Environmental Research and Public Health
Klebsiella pneumoniae is an emerging multidrug-resistant pathogen that can contaminate hospital s... more Klebsiella pneumoniae is an emerging multidrug-resistant pathogen that can contaminate hospital surfaces in the form of a biofilm which is hard to remove with standard disinfectants. Because of biofilm resistance to conservative disinfectants, the application of new disinfection technologies is becoming more frequent. Ozone gas has antimicrobial activity but there is lack of data on its action against K. pneumoniae biofilm. The aim of this study was to investigate the effects and mechanisms of action of gaseous ozone on the OXA-48-procuding K. pneumoniae biofilm. A 24 h biofilm of K. pneumoniae formed on ceramic tiles was subsequently exposed to different concentrations of ozone during one and two hours to determine the optimal ozone concentration. Afterwards, the total bacteria count, total biomass and oxidative stress levels were monitored. A total of 25 ppm of gaseous ozone was determined to be optimal ozone concentration and caused reduction in total bacteria number in all strai...
The study was carried out with the aim of establishing how the outcomes of polyelectrolyte multil... more The study was carried out with the aim of establishing how the outcomes of polyelectrolyte multilayer formation can be predicted on the basis of the results of complexation studies in solution and vice versa.
Phosphate-based drinking water softeners are commonly used to prevent scale formation in drinking... more Phosphate-based drinking water softeners are commonly used to prevent scale formation in drinking water distribution infrastructure. The main reason for drinking water softening is primarily economic (protection of pipes and extension of equipment life), while the health aspect of such treatment is usually neglected. The aim of this work is to investigate the effects of phosphate-based drinking water softeners on growth stimulation of Legionella pneumophila. Bacterial growth was observed at two different phosphate concentrations. On average, an increase in growth of 1.19–1.28 log CFU/mL was observed in selected samples with added phosphates compared with the control. The results of the in vitro experiment confirmed that the added phosphates stimulate the growth of L. pneumophila; growth stimulation could therefore be expected in drinking water distribution systems (DWDS) when phosphates are used as well. The availability of phosphorus in DWDS may be a crucial limiting factor for bio...
Osredotočili smo se na ugotavljanje mikrobiološke kakovosti vode individualnih zajetij in vodnjak... more Osredotočili smo se na ugotavljanje mikrobiološke kakovosti vode individualnih zajetij in vodnjakov, ki jo posamezniki, zlasti v ruralnih področjih, uporabljajo v gospodinjstvu, za zalivanje ali napajanje živine. Ker je problematika najbolj pereča v Prekmurju, smo posebej izpostavili to področje Slovenije. V obdobju od decembra 2008 do septembra 2009 (v zimskem in poletnem obdobju) smo odvzeli 64 vzorcev iz 32 individualnih zajetij ali vodnjakov po celotni Sloveniji, od tega 18 v Prekmurju. Za preiskave mikrobiološke kakovosti vzorcev smo uporabljali predpisane metode z mikrobiološkimi gojišči. Ob upoštevanju kriterijev mikrobiološke kakovosti za pitno vodo po Pravilniku o pitni vodi so bili neskladni vsi prekmurski vzorci, najpogostejši vzrok neskladnosti je bila prisotnost koliformnih bakterij (94 %) in povišano število aerobnih mezofilnih mikroorganizmov (67 %). Bakterija E. coli je bila ugotovljena v 50 % vzorcev. Izmed odvzetih vzorcev po vseh slovenskih regijah je bilo skladni...
V primeru naravnih ali drugih nesrec lahko v zelo kratkem casu nastopijo izredne razmere, ki ne o... more V primeru naravnih ali drugih nesrec lahko v zelo kratkem casu nastopijo izredne razmere, ki ne ogrožajo le posameznika, ampak tudi sirso skupnost. Poleg izgube cloveskih življenj in vecjega stevila poskodovanih nastane tudi velika materialna skoda. Poruseni domovi, oslabljena infrastruktura, prekinjena dobava elektricne energije in vode pripeljejo do razmer, ko si prizadeto prebivalstvo ne more samo zagotoviti osnovnih življenjskih pogojev in je odvisno od pomoci razlicnih humanitarnih organizacij. Ena taksnih je tudi mednarodna organizacija Rdecega križa, ki ima usposobljene ekipe za ukrepanje v izrednih razmerah. Clani teh ekip so usposobljeni za pridobivanje pitne vode, gradnjo zacasnih bivalisc in sanitarij, izvajanje dezinfekcije, dezinsekcije in deratizacije, pomagajo pri oskrbi z živilskimi in neživilskimi proizvodi, promociji higiene in drugo. V okviru mednarodnega projekta XH2O se je za zagotavljanje pitne vode v izrednih razmerah usposobilo 15 strokovnjakov iz Slovenije, ...
The influence of temperature, disinfectant and water softener for drinking water preparation on t... more The influence of temperature, disinfectant and water softener for drinking water preparation on the bacterial growth of Legionella pneumophila was examined.The optimal temperature for bacterial growth was 36 °C. At the incubation temperature of 15 °C the multiplying of bacteria slowed down, as confirmed by the bacteriostatic effect of this temperature. The number of bacteria was after the first 24 h of incubation at 55 °C reduced by more than 6 log in comparison to the culture at 36 °C. After 10 minutes of exposure to the disinfectant dichloroisocyanuric acid, the number of bacteria in the culture decreased for 1.4 log CFU mL-1, followed by an intensive growth immediately after the disinfectant degradation. The number of bacteria was up to 72 hours incubation even higher than in the control sample without a disinfectant, and then the number in both samples equalled at approximately 7.3 log CFU mL-1. Sodium polyphosphate used as a water softener stimulated the bacterial growth. The l...
V raziskavi smo ţeleli preuciti, kako na oprijem bakterijskih celic Legionella pneumophila subsp.... more V raziskavi smo ţeleli preuciti, kako na oprijem bakterijskih celic Legionella pneumophila subsp. pneumophila ATCC 33152 vplivajo lastnosti razlicnih vrst materialov, kot so njihova hrapavost, hidrofobnost in naboj, vpliv razlicnih temperaturnih pogojev, striţnih sil in prisotnost razkuţila dikloroizocianurne kisline ter mehcala natrijevega polifosfata. V prvem delu raziskave smo ugotavljali oprijem bakterijskih celic na steklene borosilikatne ploscice razlicnih hrapavosti, v drugem delu pa na povrsine materialov, ki se najpogosteje uporabljajo za vodovodne napeljave v zgradbah. Ti materiali so imeli razlicno sestavo, hrapavost in mejni kot. Za ugotavljanje intenzivnosti oprijema bakterij na povrsine smo uporabili spektrofotometricno metodo merjenja opticne gostote barvila kristal vijolicno, ki se sprosti iz predhodno obarvanih bakterijskih celic, oprijetih na testno povrsino. V prvem delu studije smo ugotovili, da hrapavost materiala vpliva na oprijem bakterijskih celic, saj je bil...
Zvok v človekovem naravnem in življenjskem okolju sestoji iz zvokov različnih frekvenc. Človeško ... more Zvok v človekovem naravnem in življenjskem okolju sestoji iz zvokov različnih frekvenc. Človeško uho ovrednoti raven zvočnega tlaka sorazmerno jakosti vpadnega hrupa. Raven zvočnega tlaka podajamo v decibelih (dB), višina tona pa je izražena s frekvenco, katere enota je Hertz (Hz). Prekomerna obremenitev s hrupom v človekovem okolju ima za posledico najprej zmanjšano slušno razumljivost pri medsebojnem sporazumevanju, občutek nelagodja in zmanjšano koncentracijo. Dolgotrajna izpostavljenost pa ima za posledico zmanjšano delovno sposobnost, stres, razne nevroze in delno ali celo popolno izgubo sluha. Različne študije dokazujejo, da se problemi z izpostavljenostjo visokim ravnem hrupa pojavljajo že pri predšolskih otrocih. Težišče vira hrupa so predvsem vrtci. Otroci na eni strani predstavljajo vir hrupa, po drugi strani pa jih iz medicinskega vidika uvrščamo med najbolj ogrožene skupine. Namen raziskave je bil ugotoviti dejanske ravni hrupa, katerim so otroci izpostavljeni pri različ...
The lake Bohinjsko jezero is the largest natural lake in Slovenia. It is 4.350 m long, 1.250 m wi... more The lake Bohinjsko jezero is the largest natural lake in Slovenia. It is 4.350 m long, 1.250 m wide and 45 m deep. Nevertheless, biological and chemical indicators show that the inflow of nutrients has been increasing in recent years as a result of tourism. Furthermore, the presence in the lake of coliform bacteria of faecal origin has been detected. In 2006, several locations along the lake shore were controlled to investigate the faecal bacterial contamination of the lake. In 2007, the research was expanded from the lake itself to the affluent of the lake, the Savica river and adjacent high-mountain lakes. The evaluation of coliform bacteria used “the most probable number” (MPN) method. The number of bacteria in water samples varied from 0 to more than 438 per 100-mL sample. The results support the conclusion that part of the faecal coliform bacterial population originates from septic tanks in houses and other dwellings, and a smaller part from pastures, meadows and fields in the ...
In this study we wanted to examine how the adhesion of Legionella pneumophila subsp. pneumophila ... more In this study we wanted to examine how the adhesion of Legionella pneumophila subsp. pneumophila ATCC 33152 bacterial cells is affected by the properties of various types of materials, such as roughness, hydrophobicity and charge, and how the bacteria are affected by different temperature conditions, shear forces and the presence of disinfectants dichloroisocyanuric acid and water softeners sodium polyphosphate. In the first part of the study we determined the adhesion of bacterial cells on borosilicate glass coupons of different roughness, while in the second part adhesion on the surface of materials that are most commonly used for plumbing and ventilation sistems in buildings. The materials differed in composition, roughness and contact angle. The adhesion of the bacteria to different surfaces was determined by the spectrophotometric measurement of the optical density of crystal violet dye released from the stained bacterial cells adhering to the test surface. In the first part of...
Preventing bacterial attachment to surfaces is the most efficient approach to controlling biofilm... more Preventing bacterial attachment to surfaces is the most efficient approach to controlling biofilm proliferation. The aim of this study was to compare anti-adhesion potentials of 5 and 50 mmol/L polyelectrolyte multilayers of poly(allylamine hydrochloride)/poly(sodium 4–styrenesulfonate), poly(4-vinyl-N-ethylpyridinium bromide)/ poly(sodium 4–styrenesulfonate), and poly(4-vinyl-N-isobutylpyridinium bromide)/poly(sodium 4–styrenesulfonate) against Escherichia coli. Glass surface was covered with five polyelectrolyte layers and exposed to bacterial suspensions. Poly(4-vinyl-N-ethylpyridinium bromide)/poly(sodium 4–styrenesulfonate) was the most effective against bacterial adhesion, having reduced it by 60 %, followed by poly(4-vinyl-N-isobutylpyridinium bromide)/poly(sodium 4– styrenesulfonate) (47 %), and poly(allylamine hydrochloride)/poly(sodium 4–styrenesulfonate) (38 %). Polyelectrolyte multilayers with quaternary amine groups have a significant anti-adhesion potential and could f...
Sanitarno inženirstvo International Journal of Sanitary Engineering Research
Biofilms on food contact materials represent public health issues because they are resistant to c... more Biofilms on food contact materials represent public health issues because they are resistant to cleaning and disinfection. This study aims to assess the Bacillus cereus biofilm formation capacity on silicone, polyethylene terephthalate, Teflon, and aluminium food contact materials. The biofilm biomass was analysed with the crystal violet assay method. We used the standard strain B. cereus CCM 2010, wild strain B. cereus 100 and spores of those two strains. The results show that both the vegetative form the bacteria and it spores form large amounts of biofilm on silicone, followed by polyethylene terephthalate, Teflon, and aluminium. More detailed analysis has shown that spores form more biomass on all materials in comparison to the vegetative form and that the standard strains form low levels of biofilm in contrast to the wild strains. Selecting proper material with the lowest biofilm formation potential can prevent or reduce food contamination and consequently increase food safety.
The study was carried out with the aim of establishing how the outcomes of polyelectrolyte multil... more The study was carried out with the aim of establishing how the outcomes of polyelectrolyte multilayer formation can be predicted on the basis of the results of complexation studies in solution and vice versa.
International Journal of Environmental Health Research, Dec 12, 2017
The aim of this study was to analyze the impact of hydrodynamic forces on the multiplication of E... more The aim of this study was to analyze the impact of hydrodynamic forces on the multiplication of E. coli, and biofilm formation and dispersion. The experiments were provided in a flow chamber simulating a cleaning-in-place system. Biofilm biomass was measured using a crystal violet dye method. The results show that hydrodynamic forces affect not only biofilm formation and dispersion but the multiplication of E. coli in the first place. We found more biofilm biomass on the rough surface than on the smooth one. The results of the biofilm formation test show that laminar flow promotes the biofilm growth over 72 h, meanwhile turbulent flow after 48 h causes decrease in biomass. The results of the biofilm dispersion test, in contrast, show that laminar flow removed less biofilm from both materials that turbulent flow did. Therefore, taking into account these findings in cleaning-in-place technology can substantially reduce E. coli multiplication and biofilm formation.
V primeru naravnih ali drugih nesreč lahko v zelo kratkem času nastopijo izredne razmere, ki ne o... more V primeru naravnih ali drugih nesreč lahko v zelo kratkem času nastopijo izredne razmere, ki ne ogrožajo le posameznika, ampak tudi širšo skupnost. Poleg izgube človeških življenj in večjega števila poškodovanih nastane tudi velika materialna škoda. Porušeni domovi, oslabljena infrastruktura, prekinjena dobava električne energije in vode pripeljejo do razmer, ko si prizadeto prebivalstvo ne more samo zagotoviti osnovnih življenjskih pogojev in je odvisno od pomoči različnih humanitarnih organizacij. Ena takšnih je tudi mednarodna organizacija Rdečega križa, ki ima usposobljene ekipe za ukrepanje v izrednih razmerah. Člani teh ekip so usposobljeni za pridobivanje pitne vode, gradnjo začasnih bivališč in sanitarij, izvajanje dezinfekcije, dezinsekcije in deratizacije, pomagajo pri oskrbi z živilskimi in neživilskimi proizvodi, promociji higiene in drugo. V okviru mednarodnega projekta XH2O se je za zagotavljanje pitne vode v izrednih razmerah usposobilo 15 strokovnjakov iz Slovenije, ...
Workers spend a lot of time at work, and therefore, it is important to ensure healthy workplaces.... more Workers spend a lot of time at work, and therefore, it is important to ensure healthy workplaces. The aim of this study was to evaluate the ergonomic strains of accountants and suggest measures to overcome the work-related overload and improve the working conditions. We monitored the work of three accountants through the Ovako Working posture Assessment System (OWAS) methodology and measured the microclimate and lighting conditions. The results of microclimate conditions show that the room temperature was 26 °C, the humidity was 47 %, and the airflow 0.11 ms-1. The results of the OWAS methodology gave us insights into the overload of the spine and the upper and lower limbs. In most cases, corrective measures are needed. Immediate measures need to be implemented for the upper limb load for all the observed subjects, while arm load needs to be further researched. Our findings could reduce the work-related discomforts if workers and employers followed our recommendations
International Journal of Environmental Research and Public Health
Klebsiella pneumoniae is an emerging multidrug-resistant pathogen that can contaminate hospital s... more Klebsiella pneumoniae is an emerging multidrug-resistant pathogen that can contaminate hospital surfaces in the form of a biofilm which is hard to remove with standard disinfectants. Because of biofilm resistance to conservative disinfectants, the application of new disinfection technologies is becoming more frequent. Ozone gas has antimicrobial activity but there is lack of data on its action against K. pneumoniae biofilm. The aim of this study was to investigate the effects and mechanisms of action of gaseous ozone on the OXA-48-procuding K. pneumoniae biofilm. A 24 h biofilm of K. pneumoniae formed on ceramic tiles was subsequently exposed to different concentrations of ozone during one and two hours to determine the optimal ozone concentration. Afterwards, the total bacteria count, total biomass and oxidative stress levels were monitored. A total of 25 ppm of gaseous ozone was determined to be optimal ozone concentration and caused reduction in total bacteria number in all strai...
The study was carried out with the aim of establishing how the outcomes of polyelectrolyte multil... more The study was carried out with the aim of establishing how the outcomes of polyelectrolyte multilayer formation can be predicted on the basis of the results of complexation studies in solution and vice versa.
Phosphate-based drinking water softeners are commonly used to prevent scale formation in drinking... more Phosphate-based drinking water softeners are commonly used to prevent scale formation in drinking water distribution infrastructure. The main reason for drinking water softening is primarily economic (protection of pipes and extension of equipment life), while the health aspect of such treatment is usually neglected. The aim of this work is to investigate the effects of phosphate-based drinking water softeners on growth stimulation of Legionella pneumophila. Bacterial growth was observed at two different phosphate concentrations. On average, an increase in growth of 1.19–1.28 log CFU/mL was observed in selected samples with added phosphates compared with the control. The results of the in vitro experiment confirmed that the added phosphates stimulate the growth of L. pneumophila; growth stimulation could therefore be expected in drinking water distribution systems (DWDS) when phosphates are used as well. The availability of phosphorus in DWDS may be a crucial limiting factor for bio...
Osredotočili smo se na ugotavljanje mikrobiološke kakovosti vode individualnih zajetij in vodnjak... more Osredotočili smo se na ugotavljanje mikrobiološke kakovosti vode individualnih zajetij in vodnjakov, ki jo posamezniki, zlasti v ruralnih področjih, uporabljajo v gospodinjstvu, za zalivanje ali napajanje živine. Ker je problematika najbolj pereča v Prekmurju, smo posebej izpostavili to področje Slovenije. V obdobju od decembra 2008 do septembra 2009 (v zimskem in poletnem obdobju) smo odvzeli 64 vzorcev iz 32 individualnih zajetij ali vodnjakov po celotni Sloveniji, od tega 18 v Prekmurju. Za preiskave mikrobiološke kakovosti vzorcev smo uporabljali predpisane metode z mikrobiološkimi gojišči. Ob upoštevanju kriterijev mikrobiološke kakovosti za pitno vodo po Pravilniku o pitni vodi so bili neskladni vsi prekmurski vzorci, najpogostejši vzrok neskladnosti je bila prisotnost koliformnih bakterij (94 %) in povišano število aerobnih mezofilnih mikroorganizmov (67 %). Bakterija E. coli je bila ugotovljena v 50 % vzorcev. Izmed odvzetih vzorcev po vseh slovenskih regijah je bilo skladni...
V primeru naravnih ali drugih nesrec lahko v zelo kratkem casu nastopijo izredne razmere, ki ne o... more V primeru naravnih ali drugih nesrec lahko v zelo kratkem casu nastopijo izredne razmere, ki ne ogrožajo le posameznika, ampak tudi sirso skupnost. Poleg izgube cloveskih življenj in vecjega stevila poskodovanih nastane tudi velika materialna skoda. Poruseni domovi, oslabljena infrastruktura, prekinjena dobava elektricne energije in vode pripeljejo do razmer, ko si prizadeto prebivalstvo ne more samo zagotoviti osnovnih življenjskih pogojev in je odvisno od pomoci razlicnih humanitarnih organizacij. Ena taksnih je tudi mednarodna organizacija Rdecega križa, ki ima usposobljene ekipe za ukrepanje v izrednih razmerah. Clani teh ekip so usposobljeni za pridobivanje pitne vode, gradnjo zacasnih bivalisc in sanitarij, izvajanje dezinfekcije, dezinsekcije in deratizacije, pomagajo pri oskrbi z živilskimi in neživilskimi proizvodi, promociji higiene in drugo. V okviru mednarodnega projekta XH2O se je za zagotavljanje pitne vode v izrednih razmerah usposobilo 15 strokovnjakov iz Slovenije, ...
The influence of temperature, disinfectant and water softener for drinking water preparation on t... more The influence of temperature, disinfectant and water softener for drinking water preparation on the bacterial growth of Legionella pneumophila was examined.The optimal temperature for bacterial growth was 36 °C. At the incubation temperature of 15 °C the multiplying of bacteria slowed down, as confirmed by the bacteriostatic effect of this temperature. The number of bacteria was after the first 24 h of incubation at 55 °C reduced by more than 6 log in comparison to the culture at 36 °C. After 10 minutes of exposure to the disinfectant dichloroisocyanuric acid, the number of bacteria in the culture decreased for 1.4 log CFU mL-1, followed by an intensive growth immediately after the disinfectant degradation. The number of bacteria was up to 72 hours incubation even higher than in the control sample without a disinfectant, and then the number in both samples equalled at approximately 7.3 log CFU mL-1. Sodium polyphosphate used as a water softener stimulated the bacterial growth. The l...
V raziskavi smo ţeleli preuciti, kako na oprijem bakterijskih celic Legionella pneumophila subsp.... more V raziskavi smo ţeleli preuciti, kako na oprijem bakterijskih celic Legionella pneumophila subsp. pneumophila ATCC 33152 vplivajo lastnosti razlicnih vrst materialov, kot so njihova hrapavost, hidrofobnost in naboj, vpliv razlicnih temperaturnih pogojev, striţnih sil in prisotnost razkuţila dikloroizocianurne kisline ter mehcala natrijevega polifosfata. V prvem delu raziskave smo ugotavljali oprijem bakterijskih celic na steklene borosilikatne ploscice razlicnih hrapavosti, v drugem delu pa na povrsine materialov, ki se najpogosteje uporabljajo za vodovodne napeljave v zgradbah. Ti materiali so imeli razlicno sestavo, hrapavost in mejni kot. Za ugotavljanje intenzivnosti oprijema bakterij na povrsine smo uporabili spektrofotometricno metodo merjenja opticne gostote barvila kristal vijolicno, ki se sprosti iz predhodno obarvanih bakterijskih celic, oprijetih na testno povrsino. V prvem delu studije smo ugotovili, da hrapavost materiala vpliva na oprijem bakterijskih celic, saj je bil...
Zvok v človekovem naravnem in življenjskem okolju sestoji iz zvokov različnih frekvenc. Človeško ... more Zvok v človekovem naravnem in življenjskem okolju sestoji iz zvokov različnih frekvenc. Človeško uho ovrednoti raven zvočnega tlaka sorazmerno jakosti vpadnega hrupa. Raven zvočnega tlaka podajamo v decibelih (dB), višina tona pa je izražena s frekvenco, katere enota je Hertz (Hz). Prekomerna obremenitev s hrupom v človekovem okolju ima za posledico najprej zmanjšano slušno razumljivost pri medsebojnem sporazumevanju, občutek nelagodja in zmanjšano koncentracijo. Dolgotrajna izpostavljenost pa ima za posledico zmanjšano delovno sposobnost, stres, razne nevroze in delno ali celo popolno izgubo sluha. Različne študije dokazujejo, da se problemi z izpostavljenostjo visokim ravnem hrupa pojavljajo že pri predšolskih otrocih. Težišče vira hrupa so predvsem vrtci. Otroci na eni strani predstavljajo vir hrupa, po drugi strani pa jih iz medicinskega vidika uvrščamo med najbolj ogrožene skupine. Namen raziskave je bil ugotoviti dejanske ravni hrupa, katerim so otroci izpostavljeni pri različ...
The lake Bohinjsko jezero is the largest natural lake in Slovenia. It is 4.350 m long, 1.250 m wi... more The lake Bohinjsko jezero is the largest natural lake in Slovenia. It is 4.350 m long, 1.250 m wide and 45 m deep. Nevertheless, biological and chemical indicators show that the inflow of nutrients has been increasing in recent years as a result of tourism. Furthermore, the presence in the lake of coliform bacteria of faecal origin has been detected. In 2006, several locations along the lake shore were controlled to investigate the faecal bacterial contamination of the lake. In 2007, the research was expanded from the lake itself to the affluent of the lake, the Savica river and adjacent high-mountain lakes. The evaluation of coliform bacteria used “the most probable number” (MPN) method. The number of bacteria in water samples varied from 0 to more than 438 per 100-mL sample. The results support the conclusion that part of the faecal coliform bacterial population originates from septic tanks in houses and other dwellings, and a smaller part from pastures, meadows and fields in the ...
In this study we wanted to examine how the adhesion of Legionella pneumophila subsp. pneumophila ... more In this study we wanted to examine how the adhesion of Legionella pneumophila subsp. pneumophila ATCC 33152 bacterial cells is affected by the properties of various types of materials, such as roughness, hydrophobicity and charge, and how the bacteria are affected by different temperature conditions, shear forces and the presence of disinfectants dichloroisocyanuric acid and water softeners sodium polyphosphate. In the first part of the study we determined the adhesion of bacterial cells on borosilicate glass coupons of different roughness, while in the second part adhesion on the surface of materials that are most commonly used for plumbing and ventilation sistems in buildings. The materials differed in composition, roughness and contact angle. The adhesion of the bacteria to different surfaces was determined by the spectrophotometric measurement of the optical density of crystal violet dye released from the stained bacterial cells adhering to the test surface. In the first part of...
Preventing bacterial attachment to surfaces is the most efficient approach to controlling biofilm... more Preventing bacterial attachment to surfaces is the most efficient approach to controlling biofilm proliferation. The aim of this study was to compare anti-adhesion potentials of 5 and 50 mmol/L polyelectrolyte multilayers of poly(allylamine hydrochloride)/poly(sodium 4–styrenesulfonate), poly(4-vinyl-N-ethylpyridinium bromide)/ poly(sodium 4–styrenesulfonate), and poly(4-vinyl-N-isobutylpyridinium bromide)/poly(sodium 4–styrenesulfonate) against Escherichia coli. Glass surface was covered with five polyelectrolyte layers and exposed to bacterial suspensions. Poly(4-vinyl-N-ethylpyridinium bromide)/poly(sodium 4–styrenesulfonate) was the most effective against bacterial adhesion, having reduced it by 60 %, followed by poly(4-vinyl-N-isobutylpyridinium bromide)/poly(sodium 4– styrenesulfonate) (47 %), and poly(allylamine hydrochloride)/poly(sodium 4–styrenesulfonate) (38 %). Polyelectrolyte multilayers with quaternary amine groups have a significant anti-adhesion potential and could f...
Sanitarno inženirstvo International Journal of Sanitary Engineering Research
Biofilms on food contact materials represent public health issues because they are resistant to c... more Biofilms on food contact materials represent public health issues because they are resistant to cleaning and disinfection. This study aims to assess the Bacillus cereus biofilm formation capacity on silicone, polyethylene terephthalate, Teflon, and aluminium food contact materials. The biofilm biomass was analysed with the crystal violet assay method. We used the standard strain B. cereus CCM 2010, wild strain B. cereus 100 and spores of those two strains. The results show that both the vegetative form the bacteria and it spores form large amounts of biofilm on silicone, followed by polyethylene terephthalate, Teflon, and aluminium. More detailed analysis has shown that spores form more biomass on all materials in comparison to the vegetative form and that the standard strains form low levels of biofilm in contrast to the wild strains. Selecting proper material with the lowest biofilm formation potential can prevent or reduce food contamination and consequently increase food safety.
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