Spore Contamination Research Articles

Comparison of indoor fungal spore levels before and after professional home remediation

Methods for assessing and controlling fungi in the indoor environment have been well documented, but the role of fungal allergen avoidance and respiratory disease control is just beginning to be studied. To investigate indoor fungal spore levels to determine if remediation produced reduction of these levels. The study was performed on homes remediated for excessive fungal load during 2000 to 2002. Homes were included in the study if they had professional fungal remediation. Airborne spore samples were taken both before and after remediation. Slides were mounted with glycerin jelly that contained Calberla's solution. Spores were identified and counted microscopically at a magnification of X 1000. Counts were represented as the number of spores per cubic meter of air. Preevaluations and postevaluations were conducted for 17 structures. There were 92 individual collections before remediation and 99 collections after remediation. Mean counts were 131,687 (median, 9461) before remediation and 1291 (median, 409) after remediation. Aspergillus and Penicillium spores (which were counted together) occurred with the highest frequency in preremediation structures (88%). Stachybotrys spores were present in 53% of structures before remediation. Cladosporium spores were found in highest frequency in postremediation collections. Preremediation houses contained at least a 1-log increase in AspergilluslPenicillium spores over outside collections. In postremediation houses, indoor spore counts averaged 18% of outdoor counts. Remediation for indoor fungal spore contamination can significantly reduce spore counts. Indoor collections in preremediation buildings are generally much higher than outdoor counts for critical spore types, including Aspergillus/Penicillium and Stachybotrys. Remediation provides indoor spore levels substantially lower than outdoor counts.

Propagation of Gigaspora sp dan Acaulospora sp by pot culture in a green house

Spore production of Arbuscular Mycorrhizal Fungi (AMF) was usually carried out in pot culture with sorghum and P. phaseoloides. as host plants. Host plant, genotype of AMF, and growth container are important factors for AMF spores production. The objectives of this research were to observe (i) the effect of growth container, AMF species, and host plants on spore production of G. margarita and A. tuberculata, (ii) the effect of those combinations on spore productions, and (iii) the compatibility of host plant-AMF interaction on spore production.The experiment was conducted in green house condition, G. margarita and A. tuberculata were cultured in Petri dish and colored glass plastic pot containing zeolith as a carrier with sorghum and P. phaseoloides, as host plants. Completely Randomized Design with Factorial 2x2x2x5 was used in this experiment. The results showed that spore production increased in line with the increase of host plant age. The highest spore number was obtained from G. margarita with P. phaseoloides as host plant producing 155 spores/50 g inoculum, on the otherhand spore production of A. tuberculata with P. phaseoloides as host was 161 spores/50 g inoculum. The average root infection occurred in 5 month old host plant i.e. around 90 % in 5-month-old host plant. The best container for inoculum production is the coloured plastic pot, however Petri dish considered as the best growth container for producing uniform spores and the contamination of other spores could be inhibited. Based on the result It could be concluded that sorghum and P. phaseoloides, can be further developed as host plants for mass production of Gigaspora margarita and Acaulospora tuberculata spores.© 2007 Jurusan Biologi FMIPA UNS SurakartaKey words: Pueraria phaseoloides, sorghum, Gigaspora margarita, Acaulospora tuberculata, pot culture, AMF production.

Tetanus in Injecting Drug Users, United Kingdom

Tetanus in Injecting Drug Users, United Kingdom

A ‘dirty’ business: testing the limitations of terminal restriction fragment length polymorphism (TRFLP) analysis of soil fungi

Terminal restriction fragment length polymorphism (TRFLP) is an increasingly popular method in molecular ecology. However, several key limitations of this method have not been fully examined especially when used to study fungi. We investigated the impact of spore contamination, intracollection ribosomal DNA internal transcribed spacer (ITS) region variation, and conserved restriction enzyme recognition loci on the results produced by TRFLP to characterize soil fungal communities. We find that (i) the potential for nontarget structures such as spores to contribute DNA to target sample extractions is high; (ii) multiple fragments (i.e. 'extra peaks') per PCR primer-restriction enzyme combination can be detected that are caused by restriction enzyme inefficiency and intracollection ribosomal DNA ITS variation; and (iii) restriction enzyme digestion in conserved vs. variable gene regions leads to different characterizations of community diversity. Based on these results, we suggest that studies employing TRFLP need to include information from known, identified fungi from sites within which studies take place and not to rely only on TRFLP profiles as a short cut to fungal community description.

Transport efficiency and deposition velocity of fluidized spores in ventilation ducts

Experiments with dry, fluidized spores were conducted in a test apparatus to delineate the extent of spore contamination and deposition behavior under normal airflow conditions within a ventilation system. The surrogate biological warfare agent used in experiments was the spore-forming bacterium Bacillus atrophaeus. Viable-spore-counting methods were used in the study because they provide the most important number for estimating human health effects. Three common ventilation duct materials were evaluated: flexible plastic, galvanized steel, and internally insulated fiberglass. Transport efficiency ranged from 9 to 13% in steel and fiberglass ducts; transport efficiency was far less (0.1–4%) in plastic duct. Results showed that the deposition of surrogate biological warfare agent was significantly different in the three duct materials evaluated. All experimentally determined, dimensionless deposition velocities were in the range of theoretical predictions for dimensionless roughness, k +=10. All were 10–100 times greater than the velocities predicted for ducts with smoother surfaces, k +=0.1. For plastic duct, greater dimensionless deposition velocities were likely the result of charge forces between spores and surface. However, for the steel duct, a relatively large dimensionless deposition velocity was unexpected. These findings imply that building contamination will likely vary, depending on the specific type of duct material used throughout an affected area. Results of this study may aid in refining existing particle-transport models and remediation activities.

Micromechanical cantilever array sensors for selective fungal immobilization and fast growth detection

We demonstrate the use of micromechanical cantilever arrays for selective immobilization and fast quantitative detection of vital fungal spores. Micro-fabricated uncoated as well as gold-coated silicon cantilevers were functionalized with concanavalin A, fibronectin or immunoglobulin G. In our experiments two major morphological fungal forms were used--the mycelial form Aspergillus niger and the unicellular yeast form Saccharomyces cerevisiae, as models to explore a new method for growth detection of eukaryotic organisms using cantilever arrays. We exploited the specific biomolecular interactions of surface grafted proteins with the molecular structures on the fungal cell surface. It was found that these proteins have different affinities and efficiencies to bind the spores. Maximum spore immobilization, germination and mycelium growth was observed on the immunoglobulin G functionalized cantilever surfaces. We show that spore immobilization and germination of the mycelial fungus A. niger and yeast S. cerevisiae led to shifts in resonance frequency within a few hours as measured by dynamically operated cantilever arrays, whereas conventional techniques would require several days. The biosensor could detect the target fungi in a range of 10(3) - 10(6) CFUml(-1). The measured shift is proportional to the mass of single fungal spores and can be used to evaluate spore contamination levels. Applications lie in the field of medical and agricultural diagnostics, food- and water-quality monitoring.

Modeling the Prevalence of Bacillus cereus Spores during the Production of a Cooked Chilled Vegetable Product

In minimally processed vegetable foods, pathogenic spore-forming bacteria pose a significant hazard. As part of a quantitative risk assessment, we used Bayesian belief methods to model the uncertainty and variability of the number of Bacillus cereus spores that can be found in packets of a vegetable puree. The model combines specific information from the manufacturer, experimental data on inactivation of spores, and expert opinion concerning spore concentrations in the raw vegetables and ingredients. Sensitivity analysis revealed that spore contamination of added ingredients contributes most uncertainty to the assessment. The assessment produced a quantitative estimate of the prevalence of B. cereus spores in packets of vegetable puree at the end point of the manufacturing process.

Molecular epidemiology of Paenibacillus larvae larvae and incidence of American foulbrood in Argentinean honeys from Buenos Aires province

SUMMARYPaenibacillus larvae larvae, the causative agent of American foulbrood disease of honey bee larvae occurs throughout the world and is found in all beekeeping areas of Argentina. Microbiological analysis of 394 honey samples obtained from bee hives from Buenos Aires province (Argentina) from three years of sampling (1999–2001) yielded 219 positive cases (55.6%). The incidence of P l. larvae infected honey samples for 1999 was 68.1% (n = 160), for 2000 47.1% (n = 102), and 46.2% for 2001 (n = 132). The mean values of spore contamination for the three-year study showed a continuous reduction, probably due to good practices of disease management by beekeepers by breeding bees for hygienic behaviour and reduction of antibiotic treatments for control of AFB. P. l. larvae populations isolated from honey were characterized on the basis of DNA fingerprints using the repetitive-sequence-based polymerase chain reaction technique (rep-PCR) with BOX- and REP- sequence- specific primers. Four distinctive patterns, named A, B, C, and D, were distinguishable among the isolates. Genotype D was not observed in previous studies; this finding could be correlated with a new introduction of the disease in Argentina since 1997 when only three genotypes (A, B, and C) were confirmed. The rep-PCR fingerprint patterns obtained were compared with the patterns generated by a world-wide collection of P. l. larvae strains. The same 4 genotypes patterns were found within a collection of strains from 18 different countries of the world. It is important to point out that pattern C was only found in Argentina and in one sample from Uruguay located in the border line, suggesting that genotype C could have been derived from genotype A and disseminated to Uruguay from Argentina. These findings support the hypothesis that American foulbrood disease is exposed to a limited selective pressure from climatic and environmental sources.

Prevalence of Microsporidian Spores Shed by Asymptomatic Lovebirds: Evidence for a Potential Emerging Zoonosis

Several reports implicate Encephalitozoon hellem, a microsporidian parasite first described in humans and later in birds, as the causative agent of severe disease in immunocompromised patients. This study was conducted to assess the prevalence of microsporidian spores shed in the droppings of lovebirds. During a 7-month period, a total of 198 apparently healthy lovebirds from 8 flocks in Texas were sampled, including 113 peach-faced lovebirds (Agapornis roseicollis), 32 masked lovebirds (Agapornis personata), and 53 Fischer's lovebirds (Agapornis fischeri). Smears made from cloacal swab samples of individual birds were stained with calcofluor white M2R stain and examined for the presence of spores. Microsporidian spores were identified in the droppings of 25% of the lovebirds sampled. Peach-faced and masked lovebirds were more likely to shed spores than were Fischer's lovebirds (χ2 = 15.905, P < .001). No difference in spore shedding was found between juvenile and adult birds (χ2 = 0.157, P = .692; odds ratio = 1.659; 95% CI, 0.736–3.736). Lovebirds (n = 111) were also assayed for psittacine beak and feather disease virus by polymerase chain reaction (PCR) testing of individual blood samples. Lovebirds that were PCR positive for psittacine beak and feather disease virus (n = 23) were approximately 3 times more likely to shed microsporidian spores than were lovebirds that were PCR negative (χ2 = 3.981, P = .046; odds ratio = 2.6; 95% CI, 1.013–6.754). These results suggest that companion birds without obvious clinical illness commonly shed microsporidian spores. These birds may be a source of spore contamination for opportunistic infections in humans.

Combined high-pressure and thermal treatments for processing of tomato puree: evaluation of microbial inactivation and quality parameters

The effects of combined high-pressure thermal treatments on consistency, viscosity, colour, lycopene content, enzyme activity and micro-organisms were determined, and compared to conventional pasteurisation and sterilisation processes of tomato puree. High-pressure processing at ambient temperature (HPP) improved the colour and viscosity compared to heat pasteurisation, while the water binding capacity and lycopene content were unaffected by HPP. Products treated at 700 MPa, 20 °C resulted in inactivation of the natural flora to a level below the detection limit. After pressure treatment and during chilled storage a increase in viscosity was observed. HPP caused partial inactivation of polygalacturonase (70%), but activation of pectin methylesterase. After high-pressure sterilisation treatments combined with elevated starting temperatures (≥80 °C, HPS, one or two pulses) an ambient stable product was obtained. HPS (one pulse, 700 MPa, 30 s, 90 °C) reduced B. stearothermophilus spore contamination level in inoculated meatballs in tomato puree with at least 4.5 log units. HPS resulted in more than 99% inactivation of polygalacturonase and pectin methylesterase. HPS resulted in a lower viscosity compared to conventional sterilised samples, whereas the water binding capacity was improved. Colour appreciation was improved and lycopene content was retained compared to a 40% loss after conventional sterilisation.

First Report of Anthracnose of Gaultheria procumbens Caused by Colletotrichum gloeosporioides.

In 2001, a stem canker and dieback associated with a Colletotrichum sp. was observed on Gaultheria procumbens L. (wintergreen) seedlings grown from seed in soilless potting mix at four commercial nurseries in coastal British Columbia, Canada. Black, water-soaked lesions developed into tan cankers girdling stems and petioles, and a black rot extended into the base of leaves. In 2002, a Colletotrichum sp. was isolated from similar stem cankers from wintergreen plants. One flat of healthy, 13-week-old seedlings of G. procumbens (one- to three-leaf stage; approximately 380 seedlings per flat) was inoculated with a mycelial and spore suspension of one of the Colletotrichum sp. isolates at 108 CFU/ml using a hand atomizer. The flat was covered with black plastic for 24 h after inoculation and maintained in a growth chamber at 22°C with overhead watering. After 7 days, 98% of seedlings in the inoculated flat were necrotic with abundant sporulation of the Colletotrichum fungus on stem and petiole lesions. Plants in noninoculated flats remained healthy. Reisolation of the fungus from symptomatic tissues confirmed the causal agent to be Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz, based on morphology (1,2) and polymerase chain reaction (PCR) using the species-specific primer CgInt (3). Cylindrical, hyaline, aseptate conidia measuring 16 to 20 × 4 to 6 μm were produced in acervuli with setae. Perithecia of the teleomorph, Glomerella cingulata, observed on the plants and in culture, measured 100 to 128 μm in diameter and contained acsi measuring 56 to 60 × 8 to 10 μm. Ascospores were hyaline, unicellular, slightly curved, and measured 18 to 20 × 4 to 6 μm. Subsequently, a single-spore isolate of the fungus was used to inoculate 21-week-old seedlings in the greenhouse as described above. Four inoculated and four noninoculated half-flats containing an average of 160 seedlings each were randomized on the greenhouse bench and maintained at 22°C with daily overhead misting. Stem and petiole cankers appeared on 65.1% of inoculated seedlings at 10 days after inoculation (mean of four inoculated half-flats); increasing to 90.5% at 14 days. At 14 days, 5.9% of seedlings in four noninoculated half-flats were also symptomatic, possibly from spore contamination as a result of overhead watering. To our knowledge, this is the first confirmation of the causal agent of wintergreen seedling death in seed propagation nurseries in British Columbia.

Secondary Aerosolization of Viable &lt;EMPH TYPE="ITAL"&gt;Bacillus anthracis&lt;/EMPH&gt; Spores in a Contaminated US Senate Office

Bioterrorist attacks involving letters and mail-handling systems in Washington, DC, resulted in Bacillus anthracis (anthrax) spore contamination in the Hart Senate Office Building and other facilities in the US Capitol's vicinity. To provide information about the nature and extent of indoor secondary aerosolization of B anthracis spores. Stationary and personal air samples, surface dust, and swab samples were collected under semiquiescent (minimal activities) and then simulated active office conditions to estimate secondary aerosolization of B anthracis spores. Nominal size characteristics, airborne concentrations, and surface contamination of B anthracis particles (colony-forming units) were evaluated. Viable B anthracis spores reaerosolized under semiquiescent conditions, with a marked increase in reaerosolization during simulated active office conditions. Increases were observed for B anthracis collected on open sheep blood agar plates (P<.001) and personal air monitors (P =.01) during active office conditions. More than 80% of the B anthracis particles collected on stationary monitors were within an alveolar respirable size range of 0.95 to 3.5 micro m. Bacillus anthracis spores used in a recent terrorist incident reaerosolized under common office activities. These findings have important implications for appropriate respiratory protection, remediation, and reoccupancy of contaminated office environments.

Public health in the time of bioterrorism.

On Thursday, October 4, 2001, just 24 days after the tragic events of September 11, the Florida Department of Health and the Centers for Disease Control and Prevention (CDC) confirmed the first case of inhalational anthrax in the United States in more than 25 years. Recognition of this unexpected case is attributed to the alertness of local infectious disease physician Larry Bush, who promptly notified Jean Malecki, director, Palm Beach County Health Department (1,2). By Saturday, October 6, a team of federal, state, and local public health and local law enforcement investigators identified intentional Bacillus anthracis spore contamination at the patient’s workplace. These events marked the beginning of the first U.S. outbreak of bioterrorism-related anthrax and (for many of us in clinical medicine, public health, and law enforcement) ushered in the transition from tabletop bioterrorism exercises to real-world investigation and response.

Surface sampling methods for Bacillus anthracis spore contamination.

During an investigation conducted December 17–20, 2001, we collected environmental samples from a U.S. postal facility in Washington, D.C., known to be extensively contaminated with Bacillus anthracis spores. Because methods for collecting and analyzing B. anthracis spores have not yet been validated, our objective was to compare the relative effectiveness of sampling methods used for collecting spores from contaminated surfaces. Comparison of wipe, wet and dry swab, and HEPA vacuum sock samples on nonporous surfaces indicated good agreement between results with HEPA vacuum and wipe samples. However, results from HEPA vacuum sock and wipe samples agreed poorly with the swab samples. Dry swabs failed to detect spores >75% of the time they were detected by wipe and HEPA vacuum samples. Wipe samples collected after HEPA vacuum samples and HEPA vacuum samples after wipe samples indicated that neither method completely removed spores from the sampled surfaces.

REMOVAL KINETICS OF BACILLUS CEREUS SPORES FROM STAINLESS STEEL PIPES UNDER CIP PROCEDURE: INFLUENCE OF SOILING AND CLEANING CONDITIONS

ABSTRACTCleaning efficiency is of prime importance for food industries to ensure both the quality and safety of the products. The removal kinetics of Bacillus cereus spores adhering to unheated stainless steel pipes was studied under turbulent flow conditions (Reynolds’number of 77500 and 116300) in order to be close to those encountered in industrial practice. The experimental data was fitted using a hyperbolic tangent model. Variance analysis was then performed to underline any potential effects on the kinetics of the processing parameters, such as soiling conditions, soiling media and mean walls shear stress during cleaning.A significant influence of the adhesion medium (milk or saline) is shown at the level of spore removal (P &lt; 0.001). This trend could probably be explained by the change in the surface properties of spores and stainless steel surfaces when covered by milk macromolecules. After milk soiling in turbulent flow conditions, removal efficiency was enhanced by a factor of 2.5 to remove 50% of the initial spore contamination and by a factor of 2 for the remaining spores after 30 min of cleaning. No effect of the two mean wall shear stresses (9.4 and 19.1 Pa) has been identified. The removal kinetic model proposed here could now permit the effect on the cleaning efficiency of a wide range of CIP conditions to be tested.

Detection of anthrax spores in endemic regions of northern Canada.

To determine the level of anthrax spore contamination in endemic regions of northern Canada between outbreaks. Bacterial endospores were extracted from specimens via flotation and cultured on selective PLET medium. Of 588 environmental specimens collected, 11 (1.9%) contained viable anthrax spores. High environmental concentrations of anthrax spores in northern Canada appear limited to scavenger faeces and anthrax carcass sites. Burial and cremation appear equally effective at removing anthrax spores from the immediate environment, though cremation may be improved by re-burning cremation sites containing unburned animal hair. This study describes an effective anthrax spore detection system. It provides the first bacteriological evidence that mammalian scavengers can disseminate anthrax spores in northern Canada, and its results may be compared with future environmental studies of untreated anthrax carcass sites to help improve government response plans.

IN VITRO PROPAGATION OF ANGIOPTERIS EVECTA USING SPORES

Techniques of establishing Angiopleris evecta plants in vitro were studied. Soaking of A. evecta spores in water for 24 hours markedly reduced spore contamination. Soaking of the spores in 1 -2 % of sodium hypochlorite for less than 5 minutes allowed satisfactory disinfestation without affecting spore viability. Lower concentration of minerals (1/4 MS), presence of charcoal in the medium and exposure of the spores to light were crucial for spore germination and gainetophytc development of A. evecta. Keywords: Angiopleris evecta I King fern / spore / MS medium / bleach / light / tissue culture / sporophyte / gamctophytc

Studies on the significance of pathogenic fungi in the population dynamics of the Lesser Spruce Sawfly, Pristiphora abietina Christ. (Hym., Tenthredinidae)

The population dynamics of Pristiphora abietina, an important pest in Norway spruce in central Europe, is significantly influenced by factors causing nymph mortality during the cocoon stage. In contrast to other findings reported in the literature, pathogenic fungi of the genera Beauveria, Paecilomyces and Metarhizium were found to be important natural enemies. Their epizootics occur soon after cocoon formation by the larvae in the ground litter, i.e. in June/July, and progress only slightly in autumn and winter. ‘Obscure’ mortality, which is ascribed mainly to abiotic factors, is observed more in winter. Field and laboratory experiments as well as histological analyses suggest that the fungal disease in nymphs is due to spore contamination occurring before cocoon formation, and that penetration of fungi from outside through the intact cocoon wall appears very unlikely. Thus, the infection rate of cocoons depends on the spore density in the ground litter of spruce stands during the cocoon spinning period of May/June. Perspectives for biocontrol arising from these findings are discussed.

Susceptibility of the Asian honey bee, Apis cerana, to American foulbrood, Paenibacillus larvae larvae

SUMMARYAmerican foulbrood (Paenibacillus larvae larvae), is a major concern of the beekeeping industry in Taiwan. However, disease signs have never been encountered during hive inspections of local colonies of the Asian honey bee, Apis cerana. To study the susceptibility of A. cerana larvae to AFB, various doses of P. I. larvae spores were added to larval food and disease development was monitored. Results showed that 1-day-old larvae were most susceptible, next were 2-day-old larvae, while 3-day-old larvae showed no signs of disease even when fed a large dose (4.5 × 104 spores/larva). The negative correlation between susceptibility and larval age was similar to that found for A. mellifera. Further, at the susceptible age, A. cerana larvae showed higher resistance than A. mellifera larvae when fed the same dose of spores. The dose of spores that would cause 95% mortality of A. mellifera larvae only led to 47.1 % mortality of A. cerana larvae of the same age. This resistance by A. cerana larvae apparently was not totally related to their innate immune capability. An important aspect contributing to the resistance of A. cerana was the fact that up to 82.2% of inoculated larvae were removed by adult workers before the capped stage. This adult hygienic behaviour effectively decreased the level of spore contamination inside the hive. In contrast, results showed that A. cerana pupae were more susceptible when vegetative cells of P. I. larvae were injected into the pupal haemocoel of both species of bees.

Fate of Dwarf Bunt Fungus Teliospores During Milling of Wheat into Flour

ABSTRACTWheat contaminated with teliospores of Tilletia controversa Kühn (TCK) was mixed with uncontaminated wheat and processed through the Kansas State University pilot mill. Two 50‐bu lots of the contaminated mixture were cleaned, tempered, and milled. Approximately 500 samples of wheat, cleanings, and mill fractions were collected and examined for the presence of intact and broken TCK teliospores. Whole wheat samples (50 g) were washed, sieved through a 60‐μm nylon sieve, and pelleted by centrifugation. Contents of the pellet were examined microscopically for the presence of TCK spores. The procedure was modified as needed to accommodate cleanings and mill fractions. Levels of spore contamination in whole wheat samples decreased at each step during the handling process, and large numbers of spores were found in materials that were sieved or aspirated from the grain. Very few spores were found in bran, germ, and shorts; none were detected in red dog or straight‐grade flour. The results showed that a high percentage of spores can be removed from wheat by mechanical cleaning but that it is not feasible to remove all of them.