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Nina Gundecimerman - One of the best experts on this subject based on the ideXlab platform.
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the dishwasher rubber seal acts as a reservoir of bacteria in the home environment
BMC Microbiology, 2019Co-Authors: Jerneja Zupancic, Martina Turk, Miha Crnigoj, Jerneja Ambrožic Avgustin, Nina GundecimermanAbstract:In modern lifestyles, people make their everyday tasks easier by using household appliances, for example Dishwashers. Previous studies showed massive contamination of dishwasher rubber seals with fungi, thus bacterial community, able to survive under harsh conditions, remain undetermined. Bacteria that colonise the extreme environment of household dishwasher rubber seals were investigated using cultivation-dependent and metagenomic approaches. All bacterial isolates were tested for resistance to seven selected antibiotics. Same time bacterial diversity of tap water, connected to the Dishwashers was investigated. All 30 Dishwashers investigated were colonised by various bacteria. Cultivation approaches resulted in 632 bacterial isolates in total, belonging to four phyla, eight classes, 40 genera and 74 species. The majority were Gram-positive, as solely Firmicutes (dominated by the Bacillus cereus group) and Actinobacteria. Gammaproteobacteria were primarily represented by Stenotrophomonas maltophilia, Pseudomonas aeruginosa and Escherichia coli. Metagenomic assessment of the bacterial biodiversity of the dishwasher rubber seals confirmed the predominance of Gram-positive bacteria, as primarily Actinobacteria, followed by Proteobacteria dominated by Gammaproteobacteria, and by pathogenic species such as Escherichia sp., Acinetobacter baumannii, Pseudomonas sp., Stenotrophomonas maltophilia, and Enterobacter sp.. Metagenomic assessment of bacterial biodiversity in the tap water connected to Dishwashers revealed predominance of Gram-negative bacteria, in particular Proteobacteria, mainly represented by Tepidimonas sp.. Actinobacteria showed low numbers while no Firmicutes were detected in the tap water. The bacterial diversity of tap water was also lower, 23 genera compared to 39 genera on dishwasher rubber seals. Only 13 out of 49 genera identified by metagenomics approach was found in both environments, of those Gordonia was enriched while half of 13 genera were depleted in Dishwashers compared to tap water. These data indicate that colonisation of dishwasher rubber seals probably depends primarily on the bacterial input from the dirty vessels, and much less on the bacteria in the tap water. Based on the antibiotic resistance data, the dishwasher rubber seal bacterial isolates do not represent a serious threat for the spread of antibiotic resistance into the household environment. Nevertheless Dishwashers cannot be ignored as potential sources of human infections, in particular for immuno-compromised individuals.
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ecology of the human opportunistic black yeast exophiala dermatitidis indicates preference for human made habitats
Mycopathologia, 2018Co-Authors: Monika Novak Babič, Jerneja Zupancic, Sybren De Hoog, Nina Gundecimerman, Polona ZalarAbstract:Exophiala dermatitidis is an ascomycetous black yeast from the order Chaetothyriales. Its growth characteristics include the polymorphic life cycle, ability to grow at high and low temperatures, at a wide pH range, survival at high concentrations of NaCl, and survival at high UV and radioactive radiation. Exophiala dermatitidis causes deep or localized phaeohyphomycosis in immuno-compromised people worldwide and is regularly encountered in the lungs of cystic fibrosis patients. Regardless of numerous ecological studies worldwide, little is known about its natural habitat or the possible infection routes. The present review summarizes the published data on its frequency of occurrence in nature and in man-made habitats. We additionally confirmed its presence with culture-depending methods from a variety of habitats, such as glacial meltwater, mineral water, mineral-rich salt-pan mud, Dishwashers, kitchens and different environments polluted with aromatic hydrocarbons. In conclusion, the frequency of its recovery was the highest in man-made indoor habitats, connected to water sources, and exposed to occasional high temperatures and oxidative stress.
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synergistic interactions in microbial biofilms facilitate the establishment of opportunistic pathogenic fungi in household Dishwashers
Frontiers in Microbiology, 2018Co-Authors: Jerneja Zupancic, Prem K Raghupathi, Kurt Houf, Mette Burmolle, Soren J Sorensen, Nina GundecimermanAbstract:Biofilms formed on rubber seals in Dishwashers harbor diverse microbiota. In this study, we focussed on the microbial composition of bacteria and fungi, isolated from a defined area of one square centimeter of rubber from four domestic Dishwashers and assessed their abilities to in vitro multispecies biofilm formation. A total of 80 isolates (64 bacterial and 16 fungal) were analyzed. Multiple combinations of bacterial isolates from each dishwasher were screened for synergistic interactions. 32 out of 140 tested (23%) four-species bacterial combinations displayed consistent synergism leading to an overall increase in biomass, in all experimental trails. Bacterial isolates from two of the four Dishwashers generated a high number of synergistically interacting four-species consortia. Network based correlation analyses also showed higher co-occurrence patterns observed between bacterial members in the same two dishwasher samples, indicating cooperative effects. Furthermore, two synergistic four-species bacterial consortia were tested for their abilities to incorporate an opportunistic fungal pathogen, Exophiala dermatitidis and their establishment as biofilms on sterile ethylene propylene diene monomer M-class (EPDM) rubber and polypropylene (PP) surfaces. When the bacterial consortia included E. dermatitidis, the overall cell numbers of both bacteria and fungi increased and a substantial increase in biofilm biomass was observed. These results indicate a novel phenomenon of cross kingdom synergy in biofilm formation and these observations could have potential implications for human health.
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the black yeast exophiala dermatitidis and other selected opportunistic human fungal pathogens spread from Dishwashers to kitchens
PLOS ONE, 2016Co-Authors: Jerneja Zupancic, Monika Novak Babič, Polona Zalar, Nina GundecimermanAbstract:We investigated the diversity and distribution of fungi in nine different sites inside 30 residential Dishwashers. In total, 503 fungal strains were isolated, which belong to 10 genera and 84 species. Irrespective of the sampled site, 83% of the Dishwashers were positive for fungi. The most frequent opportunistic pathogenic species were Exophiala dermatitidis, Candida parapsilosis sensu stricto, Exophiala phaeomuriformis, Fusarium dimerum, and the Saprochaete/Magnusiomyces clade. The black yeast E. dermatitidis was detected in 47% of the Dishwashers, primarily at the dishwasher rubber seals, at up to 106 CFU/cm2; the other fungi detected were in the range of 102 to 105 CFU/cm2. The other most heavily contaminated dishwasher sites were side nozzles, doors and drains. Only F. dimerum was isolated from washed dishes, while dishwasher waste water contained E. dermatitidis, Exophiala oligosperma and Sarocladium killiense. Plumbing systems supplying water to household appliances represent the most probable route for contamination of Dishwashers, as the fungi that represented the core dishwasher mycobiota were also detected in the tap water. Hot aerosols from Dishwashers contained the human opportunistic yeast C. parapsilosis, Rhodotorula mucilaginosa and E. dermatitidis (as well as common air-borne genera such as Aspergillus, Penicillium, Trichoderma and Cladosporium). Comparison of fungal contamination of kitchens without and with Dishwashers revealed that virtually all were contaminated with fungi. In both cases, the most contaminated sites were the kitchen drain and the dish drying rack. The most important difference was higher prevalence of black yeasts (E. dermatitidis in particular) in kitchens with Dishwashers. In kitchens without Dishwashers, C. parapsilosis strongly prevailed with negligible occurrence of E. dermatitidis. F. dimerum was isolated only from kitchens with Dishwashers, while Saprochaete/Magnusiomyces isolates were only found within Dishwashers. We conclude that Dishwashers represent a reservoir of enriched opportunistic pathogenic species that can spread from the dishwasher into the indoor biome.
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Dishwashers provide a selective extreme environment for human opportunistic yeast like fungi
Fungal Diversity, 2016Co-Authors: Ramazan Gumral, Jerneja Zupancic, Nina Gundecimerman, Macit Ilkit, Betil Ozhakbaysan, Aysegul Tumgor, Mehmet Ali Saracli, şinasi Taner Yildiran, Monika Novakbabic, Polona ZalarAbstract:Urban life has led to the creation of human-made environments that, from a microbiological perspective, provide extreme life conditions. Certain non-ubiquitous microorganisms such as thermophilic members of the black yeast genus Exophiala are enriched within these habitats for which no counterpart is known in nature. Dishwashers consistently accumulate a number of specific black, white and red yeasts on the rubber seals of doors and in stagnant water at the interior. Several of these yeasts are primarily known as agents of human opportunistic infections. In this review, the literature data are supported by a screening study involving 937 households in 15 cities in Turkey. Fungi were detected in 230 samples (24.5 %). Using rDNA sequencing, the prevalent species were identified as Exophiala dermatitidis (n = 116), Candida parapsilosis (n = 44), E. phaeomuriformis (n = 35), Magnusiomyces capitatus (n = 22), Rhodotorula mucilaginosa (n = 15), and C. lusitaniae (n = 14). The possible role of Dishwashers in transmitting disease is discussed.
Polona Zalar - One of the best experts on this subject based on the ideXlab platform.
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ecology of the human opportunistic black yeast exophiala dermatitidis indicates preference for human made habitats
Mycopathologia, 2018Co-Authors: Monika Novak Babič, Jerneja Zupancic, Sybren De Hoog, Nina Gundecimerman, Polona ZalarAbstract:Exophiala dermatitidis is an ascomycetous black yeast from the order Chaetothyriales. Its growth characteristics include the polymorphic life cycle, ability to grow at high and low temperatures, at a wide pH range, survival at high concentrations of NaCl, and survival at high UV and radioactive radiation. Exophiala dermatitidis causes deep or localized phaeohyphomycosis in immuno-compromised people worldwide and is regularly encountered in the lungs of cystic fibrosis patients. Regardless of numerous ecological studies worldwide, little is known about its natural habitat or the possible infection routes. The present review summarizes the published data on its frequency of occurrence in nature and in man-made habitats. We additionally confirmed its presence with culture-depending methods from a variety of habitats, such as glacial meltwater, mineral water, mineral-rich salt-pan mud, Dishwashers, kitchens and different environments polluted with aromatic hydrocarbons. In conclusion, the frequency of its recovery was the highest in man-made indoor habitats, connected to water sources, and exposed to occasional high temperatures and oxidative stress.
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the black yeast exophiala dermatitidis and other selected opportunistic human fungal pathogens spread from Dishwashers to kitchens
PLOS ONE, 2016Co-Authors: Jerneja Zupancic, Monika Novak Babič, Polona Zalar, Nina GundecimermanAbstract:We investigated the diversity and distribution of fungi in nine different sites inside 30 residential Dishwashers. In total, 503 fungal strains were isolated, which belong to 10 genera and 84 species. Irrespective of the sampled site, 83% of the Dishwashers were positive for fungi. The most frequent opportunistic pathogenic species were Exophiala dermatitidis, Candida parapsilosis sensu stricto, Exophiala phaeomuriformis, Fusarium dimerum, and the Saprochaete/Magnusiomyces clade. The black yeast E. dermatitidis was detected in 47% of the Dishwashers, primarily at the dishwasher rubber seals, at up to 106 CFU/cm2; the other fungi detected were in the range of 102 to 105 CFU/cm2. The other most heavily contaminated dishwasher sites were side nozzles, doors and drains. Only F. dimerum was isolated from washed dishes, while dishwasher waste water contained E. dermatitidis, Exophiala oligosperma and Sarocladium killiense. Plumbing systems supplying water to household appliances represent the most probable route for contamination of Dishwashers, as the fungi that represented the core dishwasher mycobiota were also detected in the tap water. Hot aerosols from Dishwashers contained the human opportunistic yeast C. parapsilosis, Rhodotorula mucilaginosa and E. dermatitidis (as well as common air-borne genera such as Aspergillus, Penicillium, Trichoderma and Cladosporium). Comparison of fungal contamination of kitchens without and with Dishwashers revealed that virtually all were contaminated with fungi. In both cases, the most contaminated sites were the kitchen drain and the dish drying rack. The most important difference was higher prevalence of black yeasts (E. dermatitidis in particular) in kitchens with Dishwashers. In kitchens without Dishwashers, C. parapsilosis strongly prevailed with negligible occurrence of E. dermatitidis. F. dimerum was isolated only from kitchens with Dishwashers, while Saprochaete/Magnusiomyces isolates were only found within Dishwashers. We conclude that Dishwashers represent a reservoir of enriched opportunistic pathogenic species that can spread from the dishwasher into the indoor biome.
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Sampling sites in the Dishwashers (A-H) and the prevailing taxa on the primary isolation plates (A.1-H.1) cultured from the particular Dishwashers sampling sites swab samples.
2016Co-Authors: Jerneja Zupancic, Monika Novak Babič, Polona Zalar, Nina Gunde-cimermanAbstract:On rubber seal (A) and detergent dispenser (B) E. dermatitidis genotype A (A.1, B.1, respectively); on rinse-aid dispenser (C) E. dermatitidis genotype A, FDSC, Saprochaete/Magnusiomyces clade (C.1); on sprinkler (D) E. dermatitidis genotype A, E. phaeomuriformis genotype 1 (D.1); on door (E) A. melanogenum, P. crustosum, E. dermatitidis genotype A, C. parapsilosis (E.1); on cutlery rack (F) FOSC, E. phaeomuriformis genotype 1, C. parapsilosis (F.1); in drain (G) E. dermatitidis genotype A, Saprochaete/ Magnusiomyces clade, Meyerozyma guilliermondii, FDSC (G.1); on side nozzles (H) FDSC (H.1). Note: not the actual state of one dishwasher, but a combination of several sampled Dishwashers.
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Dishwashers provide a selective extreme environment for human opportunistic yeast like fungi
Fungal Diversity, 2016Co-Authors: Ramazan Gumral, Jerneja Zupancic, Nina Gundecimerman, Macit Ilkit, Betil Ozhakbaysan, Aysegul Tumgor, Mehmet Ali Saracli, şinasi Taner Yildiran, Monika Novakbabic, Polona ZalarAbstract:Urban life has led to the creation of human-made environments that, from a microbiological perspective, provide extreme life conditions. Certain non-ubiquitous microorganisms such as thermophilic members of the black yeast genus Exophiala are enriched within these habitats for which no counterpart is known in nature. Dishwashers consistently accumulate a number of specific black, white and red yeasts on the rubber seals of doors and in stagnant water at the interior. Several of these yeasts are primarily known as agents of human opportunistic infections. In this review, the literature data are supported by a screening study involving 937 households in 15 cities in Turkey. Fungi were detected in 230 samples (24.5 %). Using rDNA sequencing, the prevalent species were identified as Exophiala dermatitidis (n = 116), Candida parapsilosis (n = 44), E. phaeomuriformis (n = 35), Magnusiomyces capitatus (n = 22), Rhodotorula mucilaginosa (n = 15), and C. lusitaniae (n = 14). The possible role of Dishwashers in transmitting disease is discussed.
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Dishwashers a man made ecological niche accommodating human opportunistic fungal pathogens
Fungal Biology, 2011Co-Authors: Polona Zalar, M Novak, G S De Hoog, Nina GundecimermanAbstract:Habitats in human households may accommodate microorganisms outside the common spectrum of ubiquitous saprobes. Enrichment of fungi that may require specific environmental conditions was observed in Dishwashers, 189 of which were sampled in private homes of 101 towns or communities. One-hundred-two were sampled from various localities in Slovenia; 42 from other European countries; 13 and 3 from North and South America, respectively; 5 from Israel; 10 from South Africa; 7 from Far East Asia; and 7 from Australia. Isolation was performed on samples incubated at 37 °C. Species belonging to genera Aspergillus, Candida, Magnusiomyces, Fusarium, Penicillium and Rhodotorula were found occasionally, while the black yeasts Exophiala dermatitidis and Exophiala phaeomuriformis (Chaetothyriales) were persistently and most frequently isolated. Sixty-two percent of the Dishwashers were positive for fungi, and 56 % of these accommodated Exophiala. Both Exophiala species are known to be able to cause systemic disease in humans and frequently colonize the lungs of patients with cystic fibrosis. We conclude that high temperature, high moisture and alkaline pH values typically occurring in Dishwashers can provide an alternative habitat for species also known to be pathogenic to humans.
Jerneja Zupancic - One of the best experts on this subject based on the ideXlab platform.
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the dishwasher rubber seal acts as a reservoir of bacteria in the home environment
BMC Microbiology, 2019Co-Authors: Jerneja Zupancic, Martina Turk, Miha Crnigoj, Jerneja Ambrožic Avgustin, Nina GundecimermanAbstract:In modern lifestyles, people make their everyday tasks easier by using household appliances, for example Dishwashers. Previous studies showed massive contamination of dishwasher rubber seals with fungi, thus bacterial community, able to survive under harsh conditions, remain undetermined. Bacteria that colonise the extreme environment of household dishwasher rubber seals were investigated using cultivation-dependent and metagenomic approaches. All bacterial isolates were tested for resistance to seven selected antibiotics. Same time bacterial diversity of tap water, connected to the Dishwashers was investigated. All 30 Dishwashers investigated were colonised by various bacteria. Cultivation approaches resulted in 632 bacterial isolates in total, belonging to four phyla, eight classes, 40 genera and 74 species. The majority were Gram-positive, as solely Firmicutes (dominated by the Bacillus cereus group) and Actinobacteria. Gammaproteobacteria were primarily represented by Stenotrophomonas maltophilia, Pseudomonas aeruginosa and Escherichia coli. Metagenomic assessment of the bacterial biodiversity of the dishwasher rubber seals confirmed the predominance of Gram-positive bacteria, as primarily Actinobacteria, followed by Proteobacteria dominated by Gammaproteobacteria, and by pathogenic species such as Escherichia sp., Acinetobacter baumannii, Pseudomonas sp., Stenotrophomonas maltophilia, and Enterobacter sp.. Metagenomic assessment of bacterial biodiversity in the tap water connected to Dishwashers revealed predominance of Gram-negative bacteria, in particular Proteobacteria, mainly represented by Tepidimonas sp.. Actinobacteria showed low numbers while no Firmicutes were detected in the tap water. The bacterial diversity of tap water was also lower, 23 genera compared to 39 genera on dishwasher rubber seals. Only 13 out of 49 genera identified by metagenomics approach was found in both environments, of those Gordonia was enriched while half of 13 genera were depleted in Dishwashers compared to tap water. These data indicate that colonisation of dishwasher rubber seals probably depends primarily on the bacterial input from the dirty vessels, and much less on the bacteria in the tap water. Based on the antibiotic resistance data, the dishwasher rubber seal bacterial isolates do not represent a serious threat for the spread of antibiotic resistance into the household environment. Nevertheless Dishwashers cannot be ignored as potential sources of human infections, in particular for immuno-compromised individuals.
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ecology of the human opportunistic black yeast exophiala dermatitidis indicates preference for human made habitats
Mycopathologia, 2018Co-Authors: Monika Novak Babič, Jerneja Zupancic, Sybren De Hoog, Nina Gundecimerman, Polona ZalarAbstract:Exophiala dermatitidis is an ascomycetous black yeast from the order Chaetothyriales. Its growth characteristics include the polymorphic life cycle, ability to grow at high and low temperatures, at a wide pH range, survival at high concentrations of NaCl, and survival at high UV and radioactive radiation. Exophiala dermatitidis causes deep or localized phaeohyphomycosis in immuno-compromised people worldwide and is regularly encountered in the lungs of cystic fibrosis patients. Regardless of numerous ecological studies worldwide, little is known about its natural habitat or the possible infection routes. The present review summarizes the published data on its frequency of occurrence in nature and in man-made habitats. We additionally confirmed its presence with culture-depending methods from a variety of habitats, such as glacial meltwater, mineral water, mineral-rich salt-pan mud, Dishwashers, kitchens and different environments polluted with aromatic hydrocarbons. In conclusion, the frequency of its recovery was the highest in man-made indoor habitats, connected to water sources, and exposed to occasional high temperatures and oxidative stress.
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synergistic interactions in microbial biofilms facilitate the establishment of opportunistic pathogenic fungi in household Dishwashers
Frontiers in Microbiology, 2018Co-Authors: Jerneja Zupancic, Prem K Raghupathi, Kurt Houf, Mette Burmolle, Soren J Sorensen, Nina GundecimermanAbstract:Biofilms formed on rubber seals in Dishwashers harbor diverse microbiota. In this study, we focussed on the microbial composition of bacteria and fungi, isolated from a defined area of one square centimeter of rubber from four domestic Dishwashers and assessed their abilities to in vitro multispecies biofilm formation. A total of 80 isolates (64 bacterial and 16 fungal) were analyzed. Multiple combinations of bacterial isolates from each dishwasher were screened for synergistic interactions. 32 out of 140 tested (23%) four-species bacterial combinations displayed consistent synergism leading to an overall increase in biomass, in all experimental trails. Bacterial isolates from two of the four Dishwashers generated a high number of synergistically interacting four-species consortia. Network based correlation analyses also showed higher co-occurrence patterns observed between bacterial members in the same two dishwasher samples, indicating cooperative effects. Furthermore, two synergistic four-species bacterial consortia were tested for their abilities to incorporate an opportunistic fungal pathogen, Exophiala dermatitidis and their establishment as biofilms on sterile ethylene propylene diene monomer M-class (EPDM) rubber and polypropylene (PP) surfaces. When the bacterial consortia included E. dermatitidis, the overall cell numbers of both bacteria and fungi increased and a substantial increase in biofilm biomass was observed. These results indicate a novel phenomenon of cross kingdom synergy in biofilm formation and these observations could have potential implications for human health.
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the black yeast exophiala dermatitidis and other selected opportunistic human fungal pathogens spread from Dishwashers to kitchens
PLOS ONE, 2016Co-Authors: Jerneja Zupancic, Monika Novak Babič, Polona Zalar, Nina GundecimermanAbstract:We investigated the diversity and distribution of fungi in nine different sites inside 30 residential Dishwashers. In total, 503 fungal strains were isolated, which belong to 10 genera and 84 species. Irrespective of the sampled site, 83% of the Dishwashers were positive for fungi. The most frequent opportunistic pathogenic species were Exophiala dermatitidis, Candida parapsilosis sensu stricto, Exophiala phaeomuriformis, Fusarium dimerum, and the Saprochaete/Magnusiomyces clade. The black yeast E. dermatitidis was detected in 47% of the Dishwashers, primarily at the dishwasher rubber seals, at up to 106 CFU/cm2; the other fungi detected were in the range of 102 to 105 CFU/cm2. The other most heavily contaminated dishwasher sites were side nozzles, doors and drains. Only F. dimerum was isolated from washed dishes, while dishwasher waste water contained E. dermatitidis, Exophiala oligosperma and Sarocladium killiense. Plumbing systems supplying water to household appliances represent the most probable route for contamination of Dishwashers, as the fungi that represented the core dishwasher mycobiota were also detected in the tap water. Hot aerosols from Dishwashers contained the human opportunistic yeast C. parapsilosis, Rhodotorula mucilaginosa and E. dermatitidis (as well as common air-borne genera such as Aspergillus, Penicillium, Trichoderma and Cladosporium). Comparison of fungal contamination of kitchens without and with Dishwashers revealed that virtually all were contaminated with fungi. In both cases, the most contaminated sites were the kitchen drain and the dish drying rack. The most important difference was higher prevalence of black yeasts (E. dermatitidis in particular) in kitchens with Dishwashers. In kitchens without Dishwashers, C. parapsilosis strongly prevailed with negligible occurrence of E. dermatitidis. F. dimerum was isolated only from kitchens with Dishwashers, while Saprochaete/Magnusiomyces isolates were only found within Dishwashers. We conclude that Dishwashers represent a reservoir of enriched opportunistic pathogenic species that can spread from the dishwasher into the indoor biome.
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Sampling sites in the Dishwashers (A-H) and the prevailing taxa on the primary isolation plates (A.1-H.1) cultured from the particular Dishwashers sampling sites swab samples.
2016Co-Authors: Jerneja Zupancic, Monika Novak Babič, Polona Zalar, Nina Gunde-cimermanAbstract:On rubber seal (A) and detergent dispenser (B) E. dermatitidis genotype A (A.1, B.1, respectively); on rinse-aid dispenser (C) E. dermatitidis genotype A, FDSC, Saprochaete/Magnusiomyces clade (C.1); on sprinkler (D) E. dermatitidis genotype A, E. phaeomuriformis genotype 1 (D.1); on door (E) A. melanogenum, P. crustosum, E. dermatitidis genotype A, C. parapsilosis (E.1); on cutlery rack (F) FOSC, E. phaeomuriformis genotype 1, C. parapsilosis (F.1); in drain (G) E. dermatitidis genotype A, Saprochaete/ Magnusiomyces clade, Meyerozyma guilliermondii, FDSC (G.1); on side nozzles (H) FDSC (H.1). Note: not the actual state of one dishwasher, but a combination of several sampled Dishwashers.
Dirk Bockmühl - One of the best experts on this subject based on the ideXlab platform.
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a method to evaluate factors influencing the microbial reduction in domestic Dishwashers
Journal of Applied Microbiology, 2020Co-Authors: Britta Brands, Rainer Stamminger, Schulze S Struchtrup, Dirk BockmühlAbstract:AIMS: To develop a method that is able to determine the microbial reduction in different dishwasher cleaning cycles and differentiate between different program parameters used. METHODS AND RESULTS: Stainless steel biomonitors were contaminated with Micrococcus luteus or Entereococcus faecium and cleaned in a specially programmed household dishwasher with different cleaning temperatures and durations. No detergent, bleach‐free detergent or detergent containing activated oxygen bleach was used. The logarithmic reduction (LR) was determined. The microbial reduction depended on the cleaning temperature, the duration of the cleaning cycles and the detergent type used. LR increased with higher temperatures, longer cleaning cycles and use of detergent. CONCLUSIONS: The factors cleaning cycle temperature, cleaning cycle duration, final rinsing temperature and the use of detergent all contributed to the reduction of test‐strains in dishwasher cycles. A combination of longer dishwashing cycles and increased temperatures resulted in LRₘₐₓ of the microbial load. SIGNIFICANCE AND IMPACT OF THE STUDY: Cycles in domestic appliances are very diverse; therefore a standardized method to determine their ability to reduce the microbial load is of great use. The method described here is able to demonstrate the reductions achieved by dishwashing cycles with different parameters and might help to find the necessary balance between energy saving and an acceptable level of hygiene.
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prevalence of β lactamase genes in domestic washing machines and Dishwashers and the impact of laundering processes on antibiotic resistant bacteria
Journal of Applied Microbiology, 2017Co-Authors: Laura Rehberg, André Frontzek, Asa Melhus, Dirk BockmühlAbstract:Aims: To investigate the prevalence of -lactamase genes in domestic washing machines and Dishwashers, and the decontamination efficacy of laundering.Methods and Results: For the first investigation ...
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experimental evaluation of hygienic conditions in domestic Dishwashers
Tenside Surfactants Detergents, 2015Co-Authors: Britta Brands, Dirk BockmühlAbstract:Abstract Rising environmental concerns lead to use of lower temperatures and to reduced water consumption in domestic dishwashing. The development of new Dishwashers with reservoir for reusage of water from the final rinse seeks to reduce the costs per cleaning cycle, but leads to concerns about the hygienic conditions of domestic Dishwashers, as the presence of stable communities of microorganisms has been reported. This study investigates the hygienic conditions of different types of domestic Dishwashers and the long-term effect of process parameters on the hygiene in Dishwashers with water reservoirs.
Sybren G De Hoog - One of the best experts on this subject based on the ideXlab platform.
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Dishwashers are a major source of human opportunistic yeast like fungi in indoor environments in mersin turkey
Medical Mycology, 2013Co-Authors: Aylin Dogen, Engin Kaplan, Zehra Oksuz, Mehmet Sami Serin, Macit Ilkit, Sybren G De HoogAbstract:The natural habitat of opportunistic fungal pathogens is outside of the host; therefore, it is crucial to understand their ecology and routes of transmission. In this study, we inves- tigated the presence of black and fi lamentous fungi in moist indoor environments in the city of Mersin in subtropical Turkey. In total, 177 private dwellings were screened and 893 samples obtained using cotton swabs and moistened with physiological saline from Dishwashers, washing machines, refrigerators, bath-tubs, bathroom walls, and shower heads. These were then inoculated onto malt extract agar supplemented with chloram- phenicol, followed by incubation at 37 ° C. Thirty samples (3.4%) were positive for fungi, which were then identifi ed by sequencing the rDNA internal transcribed spacer region. Exophiala dermatitidis was the most common species (23), followed by E. phaeomuri- formis (three), Magnusiomyces capitatus (two), and Candida parapsilosis (two). Geno- type A of E. dermatitidis (14) was more prevalent than genotypes B (eight) and C (one) and E. phaeomuriformis was also represented by two genotypes. Our fi ndings suggest that Dishwashers are a major indoor niche for thermophilic black yeasts. The occurrence of the opportunistic fi lamentous fungus M. capitatus in Dishwashers is consistent with a recent report.
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use of ribosomal introns as new markers of genetic diversity in exophiala dermatitidis
Fungal Biology, 2011Co-Authors: Marie Machouart, Arnaud Khemisti, Remy Dulongcourty, M. Sudhadham, Cecile Gueidan, Sybren G De HoogAbstract:Exophiala dermatitidis is one of the prevalent black yeasts found as opportunistic pathogens or colonizers in humans. In the tropics its natural habitat is thought to be fruit surfaces and it is also found in the digestive system of fruit-eating animals. However, it has recently been abundantly isolated from human-made environments (steam baths, railway ties, Dishwashers) in tropical and temperate climates. Two genotypes have been distinguished within this species: genotype A, mostly corresponding to strains isolated from patients, and genotype B, to strains isolated from the natural environment. In human-made environments, both genotypes A and B occur. A previous study suggested that one genotype had been selected for in the human host. In our study, the distribution of ribosomal insertions agrees with an ecological specialization of E. dermatitidis genotypes by showing a significantly higher frequency of ribosomal insertions in clinical strains in comparison to environmental ones. The characterization of these insertions shows that they correspond to introns of group IC or IE, the most frequent types within the fungal kingdom. These ribosomal group I introns could be used as new markers for populations of E. dermatitidis.