Passive dust collectors for assessing airborne microbial material

BACKGROUND

Settled airborne dust is used as a surrogate for airborne exposure in studies that explore indoor microbes. In order to determine whether detecting differences in dust environments would depend on the sampler type, we compared different passive, settled dust sampling approaches with respect to displaying qualitative and quantitative aspects of the bacterial and fungal indoor microbiota.

RESULTS

Settled dust sampling approaches-utilizing plastic petri dishes, TefTex material, and electrostatic dustfall collectors (EDCs)-were evaluated in indoor spaces in the USA and Finland and in an experimental chamber study. The microbial content was analyzed with quantitative PCR (qPCR) to quantify total bacterial and fungal biomass and through high-throughput sequencing to examine bacterial community composition. Bacterial composition and diversity were similar within a sampling environment regardless of the sampler type. The sampling environment was the single largest predictor of microbial community composition within a study, while sampler type was found to have much less predictive power. Quantitative analyses in indoor spaces indicated highest yields using a petri dish approach, followed by sampling with EDCs and TefTex. The highest correlations between duplicate samples were observed for EDC and petri dish approaches, indicating greater experimental repeatability for these sampler types. For the EDC samples, it became apparent that, due to the fibrous nature of the material, a rigorous extraction protocol is crucial to obtain optimal yields and stable, repeatable results.

CONCLUSIONS

Correlations between sampler types were strong both in compositional and quantitative terms, and thus, the particular choice of passive settled dust sampler is not likely to strongly alter the overall conclusion of a study that aims to characterize dust across different environments. Microbial cell abundances determined from settled dust varied with the use of different sampling approaches, and thus, consistency in the method is necessary to allow for absolute comparisons within and among studies. Considering practical aspects, petri dishes were found to be an inexpensive, simple, and feasible approach that showed the highest quantitative determinations under typical building conditions, though the choice of sampler will ultimately depend on study logistics and characteristics such as low- or high-exposure settings.

Determinants, reproducibility, and seasonal variation of bacterial cell wall components and viable counts in house dust

The objectives of this study were (i) to assess the determinants that affect concentrations of the bacterial cell wall components 3-hydroxy fatty acids (3-OH FAs) and muramic acid and of total viable bacteria and actinomycetes in house dust; and (ii) to examine the seasonal variation and reproducibility of these bacterial cell wall components in house dust. A number of lifestyle and environmental factors, mostly not consistent for different bacterial measures but commonly including the type of dwelling and farming (number of livestock), explained up to 37% of the variation of the bacterial concentrations in 212 homes in Eastern Finland. The reproducibility of 3-OH FAs and muramic acid measurements in house dust were studied in five urban homes and were found to be generally high (ICC 74-84%). Temporal variation observed in repeated sampling of the same home throughout a year was more pronounced for 3-OH FAs determinations (ICC 22%) than for muramic acid (ICC 55-66%). We conclude that determinants vary largely for different types of bacterial measurements in house dust; the measured parameters represent different aspects of the bacterial content indoors. More than one sample is needed to describe bacterial concentrations in house dust in the home environment due to large temporal variation.

Predictors of microbial agents in dust and respiratory health in the Ecrhs

Background

Dampness and mould exposure have been repeatedly associated with respiratory health. However, less is known about the specific agents provoking or arresting health effects in adult populations. We aimed to assess predictors of microbial agents in mattress dust throughout Europe and to investigate associations between microbial exposures, home characteristics and respiratory health.

Methods

Seven different fungal and bacterial parameters were assessed in mattress dust from 956 adult ECRHS II participants in addition to interview based home characteristics. Associations between microbial parameters and the asthma score and lung function were examined using mixed negative binomial regression and linear mixed models, respectively.

Results

Indoor dampness and pet keeping were significant predictors for higher microbial agent concentrations in mattress dust. Current mould and condensation in the bedroom were significantly associated with lung function decline and current mould at home was positively associated with the asthma score. Higher concentrations of muramic acid were associated with higher mean ratios of the asthma score (aMR 1.37, 95%CI 1.17-1.61). There was no evidence for any association between fungal and bacterial components and lung function.

Conclusion

Indoor dampness was associated with microbial levels in mattress dust which in turn was positively associated with asthma symptoms.

Electronic supplementary material

The online version of this article (doi:10.1186/s12890-015-0042-y) contains supplementary material, which is available to authorized users.

Domestic use of bleach and infections in children: a multicentre cross-sectional study

OBJECTIVE

To report the effects of bleach use at home on the frequency of infections in 9102 school-age children participating in the HITEA project.

METHODS

Parents of pupils aged 6-12 years from schools in Barcelona province (Spain), Utrecht province (the Netherlands) and Eastern and Central Finland were administered a questionnaire including questions on the frequency of infections (influenza, tonsillitis, sinusitis, otitis, bronchitis and pneumonia) in the past 12 months and bleach use at home. We developed multivariable mixed-effects multilogistic regression models to obtain relative risk ratios (RRR) and their 95% CI per country, and combined the RRR using random-effects meta-analyses.

RESULTS

Bleach use was common in Spain (72%, n=1945) and uncommon in Finland (7%, n=279). Overall, the prevalence of infections (recurrent or once) was higher among children of bleach users. Significant combined associations were shown for influenza only once (RRR=1.20, 95% CI 1.04 to 1.38), recurrent tonsillitis (RRR=1.35, 95% CI 1.07 to 1.71) and any infection (RRR=1.18, 95% CI 1.01 to 1.38).

CONCLUSIONS

Passive exposure to cleaning bleach in the home may have adverse effects on school-age children's health by increasing the risk of respiratory and other infections. The high frequency of use of disinfecting irritant cleaning products may be of public health concern, also when exposure occurs during childhood.

Indoor fungi: companions and contaminants

This review discusses the role of fungi and fungal products in indoor environments, especially as agents of human exposure. Fungi are present everywhere, and knowledge for indoor environments is extensive on their occurrence and ecology, concentrations, and determinants. Problems of dampness and mold have dominated the discussion on indoor fungi. However, the role of fungi in human health is still not well understood. In this review, we take a look back to integrate what cultivation-based research has taught us alongside more recent work with cultivation-independent techniques. We attempt to summarize what is known today and to point out where more data is needed for risk assessment associated with indoor fungal exposures. New data have demonstrated qualitative and quantitative richness of fungal material inside and outside buildings. Research on mycotoxins shows that just as microbes are everywhere in our indoor environments, so too are their metabolic products. Assessment of fungal exposures is notoriously challenging due to the numerous factors that contribute to the variation of fungal concentrations in indoor environments. We also may have to acknowledge and incorporate into our understanding the complexity of interactions between multiple biological agents in assessing their effects on human health and well-being.

Quantity and diversity of environmental microbial exposure and development of asthma: a birth cohort study

Background

Early-life exposure to environmental microbial agents may be associated with the development of allergies. The aim of the study was to identify better ways to characterize microbial exposure as a predictor of respiratory symptoms and allergies.

Methods

A birth cohort of 410 children was followed up until 6 years of age. Bacterial endotoxin, 3-hydroxy fatty acids, N-acetyl-muramic acid, fungal extracellular polysaccharides (EPS) from Penicillium and Aspergillus spp., β-D-glucan, ergosterol, and bacterial or fungal quantitative polymerase chain reactions (qPCRs) were analyzed from dust samples collected at 2 months of age. Asthma, wheezing, cough, and atopic dermatitis were assessed using repeated questionnaires. Specific IgEs were determined at the age of 1 and 6 years.

Results

Only few associations were found between single microbial markers and the studied outcomes. In contrast, a score for the total quantity of microbial exposure, that is, sum of indicators for fungi (ergosterol), Gram-positive (muramic acid) bacteria, and Gram-negative (endotoxin) bacteria, was significantly (inverted-U shape) associated with asthma incidence (P < 0.001): the highest risk was found at medium levels (adjusted odds ratio (aOR) 2.24, 95% confidence interval (95% CI) 0.87–5.75 for 3rd quintile) and the lowest risk at the highest level (aOR 0.34, 95% CI 0.09–1.36 for 5th quintile). The microbial diversity score, that is, sum of detected qPCRs, was inversely associated with risk of wheezing and was significantly (inverted-U shape) associated with sensitization to inhalant allergens.

Conclusion

Score for quantity of microbial exposure predicted asthma better than single microbial markers independently of microbial diversity and amount of dust. Better indicators of total quantity and diversity of microbial exposure are needed in studies on the development of asthma.

Dampness, bacterial and fungal components in dust in primary schools and respiratory health in schoolchildren across Europe

BACKGROUND

Respiratory health effects of damp housing are well recognised, but less is known about the effect of dampness and water damage in schools. The HITEA study previously reported a higher prevalence of respiratory symptoms in pupils from moisture damaged schools, but the role of specific microbial exposures remained unclear.

OBJECTIVES

To study associations between school dampness, levels of fungal and bacterial markers, respiratory symptoms and lung function in children.

METHODS

Primary schools in Spain, the Netherlands and Finland were selected on the basis of the observed presence (n=15) or absence (n=10) of moisture, dampness and/or mould. Settled dust was repeatedly sampled in 232 classrooms and levels of 14 different microbial markers and groups of microbes were determined. Parental reports of respiratory symptoms were available from 3843 children aged 6-12 years, of whom 2736 provided acceptable forced spirometry testing. Country-specific associations between exposure and respiratory health were evaluated by multilevel mixed-effects logistic and linear regression models and combined using random-effects meta-analysis.

RESULTS

The prevalence of respiratory symptoms was higher in moisture damaged schools, being more pronounced in Finnish pupils. Effects on lung function were not apparent. Levels of microbial markers were generally higher in moisture damaged schools, varied by season and were lower in Finnish schools. Wheeze tended to be inversely associated with microbial levels. All other respiratory symptoms were not consistently associated with microbial marker levels.

CONCLUSIONS

Health effects of moisture and microbial exposures may vary between countries, but this requires further study.

Determinants, reproducibility, and seasonal variation of ergosterol levels in house dust

This study aimed to clarify the determinants that affect the concentrations of ergosterol and viable fungi in house dust and to examine the seasonal variation and reproducibility of ergosterol concentrations indoors. In studying the determinants, dust samples from living room floors and vacuum cleaner dust bags were collected from 107 farming and 105 non-farming homes. Ergosterol levels were determined with gas chromatography-mass spectrometry,and the dust bag dust was cultivated for enumeration of fungal genera. Lifestyle and environmental factors, for example using of the fireplace, and visible mold observations in homes, explained 20–26% of the variation of fungal concentrations. For the reproducibility study, samples were collected from five urban homes in four different seasons. The reproducibility of ergosterol determinations within a sample was excellent (ICC = 89.8) for floor dust and moderate (ICC = 63.8) for dust bag dust, but poor when sampling the same home throughout a year (ICC = 31.3 and 12.6, respectively) due to large temporal variation in ergosterol concentrations. In conclusion, environmental characteristics only partially predicted the variation of fungal concentrations. Based on these studies, we recommend repeated sampling of dust over time if one seeks to adequately describe overall fungal levels and exposure in a home.

PRACTICAL IMPLICATIONS

This study shows that levels of ergosterol and viable fungi in house dust are related to visible mold observations. Only 20% of the variation in fungal levels can be explained with questionnaires, and therefore, environmental samples need to be taken in addition. Reproducibility of ergosterol determination was excellent for floor dust, and thus, ergosterol measurements from floor dust samples could be suitable for assessing the fungal load in building investigations. The temporal variation needs to be taken into account when describing the ergosterol concentration of urban homes.

Dampness and mould in schools and respiratory symptoms in children: the HITEA study

BACKGROUND

The adverse respiratory health effects of dampness and mould in the home have been extensively reported, but few studies have evaluated the health effects of such exposures in schools.

OBJECTIVES

To assess the associations between dampness and mould in school buildings and respiratory symptoms among 6-12-year-old pupils in three European countries with different climates.

METHODS

Based on information from self-reports and observations, we selected 29 primary schools with and 27 without moisture damage in Spain, the Netherlands and Finland. Information on respiratory symptoms and potential determinants was obtained using a parent-administered questionnaire among 6-12-year-old pupils. Country-specific associations between moisture damage and respiratory symptoms were evaluated using multivariable multilevel mixed effects logistic regression analysis.

RESULTS

Data from 9271 children were obtained. Nocturnal dry cough was consistently associated with moisture damage at school in each of the three countries: OR 1.15; 95% CI 1.00 to 1.30 with p for heterogeneity 0.54. Finnish children attending a moisture damaged school more often had wheeze (OR 1.36; CI 1.04 to 1.78), nasal symptoms (OR 1.34; CI 1.05 to 1.71) and respiratory-related school absence (OR 1.50; CI 1.10 to 2.03). No associations with these symptoms were found in the Netherlands or Spain (p for heterogeneity <0.05).

CONCLUSIONS

Moisture damage in schools may have adverse respiratory health effects in pupils. Finnish school children seem to be at higher risk, possibly due to quantitative and/or qualitative differences in exposure.

Investigation of different yeast strains for the detoxification of ochratoxin A

High concentrations of ochratoxin A (OTA) in feed lead to growth depression in animals. It has been reported that binders can be used for deactivating aflatoxins but not for other mycotoxins without negatively influencing the animals health. In this study a strain from the genus ofTrichosporon with the ability to cleave ochratoxin A very selectively into phenylalanine and the non-toxic ochratoxin α (OTα) could be isolated. This strain was selected from a pool of OTA detoxifying microorganism by carrying out several investigations.Trichosporon sp. nov. can be fermented and stabilized. In a feeding trial with broilers lyophilizedTrichosporon-cells could compensate performance losses caused by OTA.

Winter ventilation rates at primary schools: comparison between Portugal and Finland

This study focused on examination of ventilation rates in classrooms with two different types of ventilation systems: natural and mechanical. Carbon dioxide (CO2) measurements were conducted in primary schools of Portugal characterized by natural ventilation and compared to Finland where mechanical ventilation is the norm. The winter period was selected since this season exerts a great influence in naturally ventilated classrooms, where opening of windows and doors occurs due to outdoor atmospheric conditions. The ventilation rates were calculated by monitoring CO2 concentrations generated by the occupants (used as a tracer gas) and application of the buildup phase method. A comparison between both countries' results was conducted with respect to ventilation rates and how these levels corresponded to national regulatory standards. Finnish primary schools (n = 2) registered a mean ventilation rate of 13.3 L/s per person, which is higher than the recommended ventilation standards. However, the Finnish classroom that presented the lowest ventilation rate (7.2 L/s per person) displayed short-term CO2 levels above 1200 ppm, which is the threshold limit value (TLV) recommended by national guidelines. The Portuguese classrooms (n = 2) showed low ventilation rates with mean values of 2.4 L/s per person, which is markedly lower than the minimum recommended value of 7 L/s per person as defined by ASHRAE and 20% less than the REHVA minimum of 3 L/s per person. Carbon dioxide levels of 1000 ppm, close to the TLV of 1200 ppm, were also reached in both Portuguese classrooms studied. The situation in Portugal indicates a potentially serious indoor air quality problem and strengthens the need for intervention to improve ventilation rates in naturally ventilated classrooms.

Occurrence of moisture problems in schools in three countries from different climatic regions of Europe based on questionnaires and building inspections - the HITEA study

The aim of this study was to assess occurrence of dampness and mold in school buildings in three European countries (the Netherlands, Spain, and Finland), representing different climatic regions. An assessment was performed utilizing both questionnaires and on-site building investigations, and the agreement between these two methods was evaluated for validation purposes. On the basis of questionnaire data from a representative sample of schools, different types of moisture problems were reported in 24-47% of all school buildings at the time of the study. Most commonly reported was dampness in the Netherlands, moisture/water damage in Spain, and mold odor in Finland. Subsequently, 20-24 schools per country were selected for on-site inspections by trained staff. The overall agreement between the questionnaire and inspection data was good (kappa-value 0.62), however, with large differences (0.39-0.91) between countries. Extrapolating from the inspection data, the minimum estimates for prevalence of moisture problems in school buildings are 20% in the Netherlands, 41% in Spain, and 24% in Finland. In conclusion, moisture problems (such as moisture damage, dampness, and mold) are relatively common in schools. The occurrence and severity may vary across geographical areas, which can be partly explained by building characteristics.

PRACTICAL IMPLICATIONS

On the basis of this study, the prevalence of verified moisture problems in school buildings was highest in Spain, but lower and similar in Finland and the Netherlands. Questionnaire-based surveys can be used to assess moisture problems in school buildings, but because of large variation in agreement with inspection data, the questionnaire needs to be validated by on-site inspections in a subsample of the surveyed buildings.

Microbial secondary metabolites in school buildings inspected for moisture damage in Finland, The Netherlands and Spain

Secondary metabolites produced by fungi and bacteria are among the potential agents that contribute to adverse health effects observed in occupants of buildings affected by moisture damage, dampness and associated microbial growth. However, few attempts have been made to assess the occurrence of these compounds in relation to moisture damage and dampness in buildings. This study conducted in the context of the HITEA project (Health Effects of Indoor Pollutants: Integrating microbial, toxicological and epidemiological approaches) aimed at providing systematic information on the prevalence of microbial secondary metabolites in a large number of school buildings in three European countries, considering both buildings with and without moisture damage and/or dampness observations. In order to address the multitude and diversity of secondary metabolites a large number of more than 180 analytes was targeted in settled dust and surface swab samples using liquid chromatography/mass spectrometry (LC/MS) based methodology. While 42%, 58% and 44% of all samples collected in Spanish, Dutch and Finnish schools, respectively, were positive for at least one of the metabolites analyzed, frequency of detection for the individual microbial secondary metabolites - with the exceptions of emodin, certain enniatins and physcion - was low, typically in the range of and below 10% of positive samples. In total, 30 different fungal and bacterial secondary metabolites were found in the samples. Some differences in the metabolite profiles were observed between countries and between index and reference school buildings. A major finding in this study was that settled dust derived from moisture damaged, damp schools contained larger numbers of microbial secondary metabolites at higher levels compared to respective dust samples from schools not affected by moisture damage and dampness. This observation was true for schools in each of the three countries, but became statistically significant only when combining schools from all countries and thus increasing the sample number in the statistical analyses.

Geographical variation and the determinants of domestic endotoxin levels in mattress dust in Europe

Endotoxin exposures have manifold effects on human health. The geographical variation and determinants of domestic endotoxin levels in Europe have not yet been extensively described. To investigate the geographical variation and determinants of domestic endotoxin concentrations in mattress dust in Europe using data collected in the European Community Respiratory Health Survey follow-up (ECRHS II). Endotoxin levels were measured in mattress dust from 974 ECRHS II participants from 22 study centers using an immunoassay. Information on demographic, lifestyle, and housing characteristics of the participants was obtained in face-to-face interviews. The median endotoxin concentration in mattress dust ranged from 772 endotoxin units per gram (EU/g) dust in Reykjavik, Iceland, to 4806 EU/g in Turin, Italy. High average outdoor summer temperature of study center, cat or dog keeping, a high household crowding index, and visible damp patches in the bedroom were significantly associated with a higher endotoxin concentrations in mattress dust. There is a large variability in domestic endotoxin levels across Europe. Average outdoor summer temperature of study center, which explains only 10% of the variation in domestic endotoxin level by center, is the strongest meteorological determinant. The observed variation needs to be taken into account when evaluating the health effects of endotoxin exposures in international contexts.

PRACTICAL IMPLICATIONS

The incoherent observations of the health effects of endotoxin may be partly owing to the geographical heterogeneity of endotoxin exposure. Therefore, the observed variation should be considered in further studies. Measurements of indoor endotoxin are recommended as an indicator for the level of exposures of individual domestic environments.

Co-occurrence of toxic bacterial and fungal secondary metabolites in moisture-damaged indoor environments

Toxic microbial secondary metabolites have been proposed to be related to adverse health effects observed in moisture-damaged buildings. Initial steps in assessing the actual risk include the characterization of the exposure. In our study, we applied a multi-analyte tandem mass spectrometry-based methodology on sample materials of severely moisture-damaged homes, aiming to qualitatively and quantitatively describe the variety of microbial metabolites occurring in building materials and different dust sample types. From 69 indoor samples, all were positive for at least one of the 186 analytes targeted and as many as 33 different microbial metabolites were found. For the first time, the presence of toxic bacterial metabolites and their co-occurrence with mycotoxins were shown for indoor samples. The bacterial compounds monactin, nonactin, staurosporin and valinomycin were exclusively detected in building materials from moist structures, while chloramphenicol was particularly prevalent in house dusts, including settled airborne dust. These bacterial metabolites are highly bioactive compounds produced by Streptomyces spp., a group of microbes that is considered a moisture damage indicator in indoor environments. We show that toxic bacterial metabolites need to be considered as being part of very complex and diverse microbial exposures in 'moldy' buildings.

PRACTICAL IMPLICATIONS

Bacterial toxins co-occur with mycotoxins in moisture-damaged indoor environments. These compounds are measurable also in settled airborne dust, indicating that inhalation exposure takes place. In attempts to characterize exposures to microbial metabolites not only mycotoxins but also bacterial metabolites have to be targeted by the analytical methods applied. We recommend including analysis of samples of outdoor air in the course of future indoor assessments, in an effort to better understand the outdoor contribution to the indoor presence of microbial toxins. There is a need for a sound risk assessment concerning the exposure to indoor microbial toxins at concentrations detectable in moisture-damaged indoor environments.

Evaluation of settled floor dust for the presence of microbial metabolites and volatile anthropogenic chemicals in indoor environments by LC-MS/MS and GC-MS methods

This study reports on detection of a large number of biological and anthropogenic pollutants using LC-MS/MS and GC-MS technologies in settled floor dust (SFD). The latter technique was applied to obtain a general picture on the presence of microbial as well as non-microbial volatile organic compounds, whereas the targeted LC-MS/MS analysis focused on identification of species specific secondary metabolites. In the absence of moisture monitoring data the relevance of finding of stachybotrylactam and other metabolites of tertiary colonizers are confined only to accidental direct exposure to SFD. To the best of our knowledge 30 of the 71 identified volatile organic compounds (VOCs) are newly reported in SFD matrix. Coordinated application of "AMDIS and Spectconnect" was found beneficial for the evaluation and identification of prime volatile pollutants in complex environmental samples. Principal component analysis (PCA) of peak areas of 18 microbial volatile organic compounds (MVOCs) resulted in identification of nonanal as potential MVOC marker. Two more volatiles toluene and 1-tetradecanol though had discriminative influence, are not regarded as MVOC markers, considering their probable alternate origin from paints and cosmetics, respectively.

The occupant as a source of house dust bacteria

BACKGROUND

Markers for microbial groups are commonly measured in house dust samples to assess indoor exposure to microbes in studies on asthma and allergy. However, little is known about the sources of different microbes. A better understanding of the nature and origin of microbes present in the immediate environment of human beings is crucial if one wants to elucidate protective as well as adverse effects on human health.

OBJECTIVE

To determine the extent to which the bacterial composition of mattress and floor dust reflects the presence of the human body in relation to other environmental sources.

METHODS

House dust and skin surface swab samples of occupants in 4 homes were collected and analyzed for their bacterial content, using a culture-independent methodology. Bacterial sequences analyzed from the different house dusts and skin surface swabs represented random samples of bacteria present in a given sample. Highly similar sequences were grouped to assess biodiversity and to draw conclusions about the sources of bacteria.

RESULTS

The bacterial flora in the house dust samples was found to be highly diverse and dominated by gram-positive bacteria. To a considerable extent, the presence of different bacterial groups was attributed to human sources. In the individuals' mattress dust samples, 69% to 88% of the bacterial sequences analyzed were associated with human origins. The respective percentages for the individual floor dusts ranged from 45% to 55%.

CONCLUSION

Our study indicates that human-derived bacteria account for a large part of the mainly gram-positive bacterial content in house dust.

Lactobacillus rhamnosus strain GG modulates intestinal absorption, fecal excretion, and toxicity of aflatoxin B(1) in rats

In this study, the modulation of aflatoxin B(1) (AFB(1)) uptake in rats by administration of the probiotic Lactobacillus rhamnosus GG was demonstrated. Fecal AFB(1) excretion in GG-treated rats was increased via bacterial AFB(1) binding. Furthermore, AFB(1)-associated growth faltering and liver injury were alleviated with GG treatment.

Microbiologicals for deactivating mycotoxins

Mycotoxins are secondary metabolites of fungi affecting human and animal health. Five classes of mycotoxins are of major concern in animal husbandry, namely aflatoxins, trichothecenes, zearalenone, ochratoxins, and fumonisins. Due to their diverse structure these fungal toxins are able to cause a great variety of acute symptoms in animals. Clay minerals have been used in animal nutrition to bind mycotoxins, but the binders are only very specific for aflatoxins but not for other toxins. A novel strategy to control the problem of mycotoxicoses in animals is the application of microorganisms capable of biotransforming mycotoxins into nontoxic metabolites. The microbes act in the intestinal tract of animals prior to the resorption of the mycotoxins. A Eubacterium (BBSH 797) strain is able to deactivate trichothecenes by reduction of the epoxide ring (CAST, Mycotoxins, Risks in Plant, Animal and Human Systems, Task Force Report 139, Council of Agricultural Science and Technology, Ames Iowa 2003, p. 10.; Binder, E. M., Binder, J., Ellend, N., Schaffer, E. et al., in: Miraglia, M., van Egmond, H., Brera, C., Gilbert, J. (Eds.), Mycotoxins and Phycotoxins--Developments in Chemistry, Toxicology and Food Safety, Alaken, Fort Collins 1996, pp. 279-285). This strain was isolated out of bovine rumen fluid and the mode of action was proven in vitro and also in vivo. Further a novel yeast strain, capable of degrading ochratoxin A and zearalenone was isolated and characterized (Bruinink, A., Rasonyi, T., Sidler, C., Nat. Toxins 1999, 6, 173-177; Schatzmayr, G., Heidler, D., Fuchs, E., Mohnl, M. et al., Mycotoxin Res. 2003, 19, 124-128.) Due to the yeasts affiliation to the genus of Trichosporon and its property to degrade mycotoxins this strain was named Trichosporon mycotoxinivorans (Trichosporon MTV, 115).

Staphylococcus nepalensis sp. nov., isolated from goats of the Himalayan region

Four coagulase-negative, novobiocin-resistant cocci, designated CW1(T), PM34, MM3 and RW78, were isolated from the respiratory tract of goats kept in the Himalayan region. The four isolates were assigned to a single species on the basis of almost identical biochemical and physiological traits, protein profiles obtained after SDS-PAGE and identical genomic fingerprints generated after enterobacterial repetitive intergenic consensus (ERIC)-PCR. Strain CW1(T) showed highest 16S rDNA sequence similarities to Staphylococcus cohnii subsp. urealyticus ATCC 49330(T), Staphylococcus saprophyticus subsp. saprophyticus ATCC 15305(T), S. cohnii subsp. cohnii ATCC 29974(T), Staphylococcus arlettae ATCC 43957(T), Staphylococcus gallinarum ATCC 35539(T), Staphylococcus succinus ATCC 700337(T) and Staphylococcus xylosus ATCC 29971(T) (99.0, 98.8, 98.8, 98.4, 98.2, 98.1 and 98.1 %, respectively), indicating its classification within the genus Staphylococcus. The polar lipid composition, fatty acid profiles, quinone systems and diagnostic cell-wall diamino acid were in agreement with the characteristics of the genus Staphylococcus. DNA-DNA hybridization with closely related Staphylococcus species suggested that strain CW1(T) represents an as-yet unrecognized species. Based on these results, a novel species of the genus Staphylococcus is described, Staphylococcus nepalensis sp. nov. The type strain is CW1(T) (=DSM 15150(T)=CCM 7045(T)) and the most dissimilar strain is PM34 (=DSM 15151=CCM 7046).

Toxicity of ochratoxin A in aBrevibacillus brevis - Growth inhibition assay

Ochratoxin A (OTA) is a nephrotoxic, carcinogenic and immunosuppressive mycotoxin. It can be detoxified by various microorganisms, e.g. different yeast strains, via metabolisation into ochratoxin α (OTα). Within this study a growth inhibition assay was developed to compare the toxicity of OTA and its degradation product OTα. As an indicator organismBrevibacillus brevis was used. The assay was performed in microtiterplates. Growth inhibition was determined by comparing the optical density values ofBrevibacillus brevis cultures grown in medium supplemented with OTA/OTα and OTA/OTα-free medium, respectively.It could be shown thatB. brevis is sensitive to OTA (EC100=0.5 mg/L±0.03 mg/L), which is not the case for its metabolite OTα. Therefore this bioassay is a useful tool to show the detoxification of OTA to OTα by microbial degradation.

Bacillus barbaricus sp. nov., isolated from an experimental wall painting

In a project concerning bacterial colonization of experimental wall paintings, a large number of isolates have been acquired with high similarities in their whole-cell protein patterns obtained after SDS-PAGE. Of this group, four strains, designated V2-BIII-A2(T), V2-BI-A9, V2-BI-04 and V2-BII-A8, were chosen for further characterization. Banding patterns obtained after ERIC-PCR were barely distinguishable among these four strains, indicating their affiliation within a single species. The isolates also displayed nearly identical biochemical and physiological features. The chemotaxonomic characteristics, including polar lipids, quinone systems, cell-wall diamino acid composition and fatty acid profiles, were in good agreement with those of numerous previously described Bacillus species. 16S rDNA analysis of strain V2-BIII-A2(T) showed that this bacterium belongs to the genus Bacillus, with highest sequence similarities to Bacillus megaterium (94.6%), Bacillus flexus (94.4%) and the alkaliphilic Bacillus cohnii (94.2%). Based on almost identical biochemical, physiological and chemotaxonomic traits, ERIC-PCR-generated genomic fingerprints and comparative 16S rDNA sequence analysis, it is demonstrated that the four isolates represent a novel species of the genus Bacillus, for which the name Bacillus barbaricus sp. nov. is proposed. The type strain is V2-BIII-A2(T) (= CCM 4982(T) = DSM 14730(T)).