Study on Lyme borreliosis focus in the Lublin region (eastern Poland)

A suburban focus of Lyme borreliosis situated 11 km from the southern border of the city of Lublin (eastern Poland) was characterized. The focus covers an area of circa 100 km(2), surrounding 3 localities inhabited by circa 7,500 people engaged mostly in farming. It was demonstrated that on the area of focus the infection rate of Ixodes ricinus ticks with Borrelia burgdorferi, frequency of serological response of inhabitants to the antigen of Borrelia burgdorferi, and incidence of Lyme borreliosis were significantly (p<0.001) greater compared to the whole territory of Lublin province, and were respectively 13.1 % vs. 4.7 %, 33.0 % vs. 13.7 %, and 0.002 % vs. 0.00075 % .

In vitro study of pro-inflammatory and anti-tumour properties of microvesicles from bacterial cell wall of Pantoea agglomerans

In the environment, Gram-negative bacteria are capable of producing large amounts of endotoxin-containing microvesicles - spherical structures measuring 30-50 nm in diameter, emerging by fragmentation of the outer membrane of the bacterial cell wall. Microvesicles are suspected of inducing inflammatory lung diseases, but possibly also of stimulating anti-tumour defence mechanisms. The present study was aimed at assessing the pro-inflammatory and anti-tumour properties of microvesicles in vitro. Peripheral blood mononuclear cells of 5 healthy volunteers were cultured for 6 h, 24 h, 3 days, and 5 days with microvesicles (MV) of Pantoea agglomerans at concentrations ranging from 0.48-1500 microg/ml. The following outcomes were measured: secretion of IFN-gamma and TNF-alpha (by ELISA and ELISpot), intensity of cell proliferation (LPT), expression of surface markers CD8, CD14, CD16, CD25, CD69, CD80, CD83, HLA-DR, and apoptosis markers (by flow cytometry). After 24 hours, a clear dose-dependent response to microvesicles was seen for IFN-gamma production, starting already at the lowest concentration of 0.48 microg/ml (p=0.04). A 2-fold increase in TNF-alpha production was seen after 3 days at the concentration of 1,500 microg/ml (p=0.05). A clear and significant dose-dependent increase in cell proliferation in response to MV was detectable after 5 days (p=0.001). A decrease in the percentage of CD14(+)CD83(+) monocytes was observed after 1 day of culture. We conclude that IFN-gamma and TNF-alpha are triggered at different concentrations of microvesicles: at lower concentrations only IFN-gamma is upregulated, whereas at higher concentrations both IFN-gamma and TNF-alpha are secreted.

Gram-negative bacteria in water distribution systems of hospitals

A total of 67 samples of tap water were collected from faucets and showerheads in 6 hospitals located in the Lublin province (eastern Poland). The samples were examined for the presence and species composition of Legionella, Gram-negative bacteria belonging to family Enterobacteriaceae (GNB-E) and Gram-negative bacteria not belonging to family Enterobacteriaceae (GNB-NE), by filtering through cellulose filters and culture on respectively GVPC, EMB and tryptic soya agar media. On average, Legionella was isolated from 65.7% of the water samples taken in hospitals. Strains of the Legionella pneumophila types 2-14 predominated, forming 74.6% of total Legionella isolates. Legionella pneumophila type 1 strains constituted 13.5% of the total count, while other species of Legionella (referred to as Legionella spp.) formed 11.9% of the total. The concentrations of Legionella in positive water samples ranged from 3-350 cfu/100 ml. GNB-E were not found in the examined water samples. GNB-NE were isolated from 79.1% of the water samples taken in hospitals in the concentrations 11-300 cfu/100 ml. Species of the family Pseudomonadaceae predominated among GNB-NE strains isolated from the examined water samples, forming on average 71.5% of the total count. Altogether, 20 GNB-NE species were identified in the examined samples, out of which 12 were potentially pathogenic. In conclusion, Gram-negative flora of water samples taken in the examined hospitals complies with potable water sanitary standards by the lack of Enterobacteriaceae species, but creates a moderate health risk because of mediocre concentrations of Legionella and the presence of potentially pathogenic non-enterobacterial species.

Monitoring Legionella species in hospital water systems. Link with disease and evaluation of different detection methods

The aim of this work was to evaluate three currently available isolation methods for Legionella using water samples and swabs of a single pediatric hospital water system. Additionally, high risk patients were screened for the presence of Legionella pneumophila antigen in urine. Fifteen water samples and 11 swab samples were collected from distal sites at 18 sampling locations. The International Standard Method (PN-ISO11731-2) based on membrane filtration and direct culture of bacteria on selective media were compared with amoebic co-culture. The numbers of legionellae detected exceeded 10(2) cfu/100 ml in 50% of the samples. All the positive samples contained L. pneumophila SGs 2-14. Urine samples were obtained from 57 immunosuppressed children and screened for the presence of L. pneumophila serogroup (SG) 1 antigen by Legionella urinary antigen EIA. Of the 57 urine samples tested for the presence of Legionella pneumophila SG 1 antigen, none were positive. Our results highlight the value of combined membrane filtration and amoebic co-culture methods in detecting viable L. pneumophila strains. Direct plating of 0.2 ml water is a useful screening method for samples containing large bacterial amount.

Concentration and species composition of aerobic and facultatively anaerobic bacteria released to the air of a dental operation area before and after disinfection of dental unit waterlines

Bacteriological air sampling was conducted at 25 dental units during restorative treatment sessions before and after disinfection of dental unit waterlines (DUWL) with hydrogen peroxide. Air samples for determining the concentration and species composition of aerobic and facultatively anaerobic bacteria were collected with the portable Reuter Centrifugal Sampler (RCS Plus) in the dental operation area close to patient's mouth. Large concentrations of airborne bacteria in the range of 0.35-40.08 x 10(3) cfu/m(3) (median = 1.63 x 10(3) cfu/m(3)) were recorded before DUWL disinfection. After disinfection, the concentrations were significantly lower (p<0.05), ranging from 0.51-3.82 x 10(3) cfu/m(3) (median = 0.9 x 10(3) cfu/m(3)). Streptococci were most numerous among airborne bacteria before DUWL disinfection, forming 79.23 % of total isolates. The remaining isolates were staphylococci/micrococci (15.7 % ), corynebacteria (2.3 % ), endospore-forming bacilli (1.45 % ), Gram-negative bacteria (1.31 % ), and actinomycetes (0.01 % ). After DUWL disinfection, a significant decrease in the numbers of streptococci (p<0.05) and Gram-negative bacteria (p<0.01) was noted, while the numbers of other types of bacteria were unaffected. Altogether, 50 species or genera of bacteria were identified in the examined air samples before and after DUWL disinfection. Of these, 36 species or genera are considered potentially pathogenic, as a potential cause of infection, allergic disease or intoxication. In conclusion, the high pollution of dental operation area with bacteria indicates a need for use of preventive measures protecting dental staff and patients, such as DUWL disinfection that proved efficient in decrease of exposure in the present study.

Microbial contamination of dental unit waterlines

The specific structure of dental units favours the presence of biofilm and microbial contamination of the dental unit waterlines (DUWL) water. The ability of bacteria to colonize surfaces and to form biofilm in water supply tubes, including DUWL, is a common phenomenon, which has been well documented, just as with difficulties in biofilm removal and prevention of its regrowth. Microorganisms from contaminated DUWL are transmitted with aerosol and splatter, generated by working unit handpieces. On the basis of the detailed literature review, the state-of-the art knowledge of the microflora of dental unit waterlines is presented. Most of the microorganisms isolated from DUWL are of low pathogenicity. Nevertheless, the public health significance of many of the microorganisms found in DUWL is unknown. According to current knowledge, it is not the mere presence of bacteria that is important in DUWL contamination monitoring, but their number, the presence of potential pathogens, and patients' oral cavity microflora. Numerous studies emphasize the need for effective mechanisms to reduce the microbial contamination in DUWL and highlight the risk for cross-infection in general practice, especially in view of the ever-increasing number of immunocompromised persons who present at outpatient dental clinics.

Preliminary study on the occurrence of Toxoplasma gondii in Ixodes ricinus ticks from north-western Poland with the use of PCR

A batch of 259 Ixodes ricinus ticks collected by flagging in woodlands of north-western Poland (Szczecin area) was examined for the presence of Toxoplasma gondii DNA with nested polymerase chain reaction (PCR). Positive isolates were genotyped with the restriction fragment length polymorphism (RFLP) analysis of B1 gene marker. Another batch of 340 I. ricinus ticks from Szczecin area was homogenized and inoculated into mice. Subsequently, the biological material obtained from inoculated mice was also examined with nested PCR for the presence of Toxoplasma gondii DNA and positive isolates were genotyped with RFLP as above. The study revealed that 12.7 % of I. ricinus ticks were infected with T. gondii. Prevalence of T. gondii infection was highest in females (27.9 %), being significantly greater (p<0.05) than in males (12.3 % ) and nymphs (5.6 % ). Most of the positive isolates (78.8 % ) belonged to type I of T. gondii. Samples from brains and other organs of 60 inoculated mice showed 44 positive results for T. gondii DNA with the dominance of atypical genotype and frequent mixed infections.

Respiratory disorders in two workers of customs depositories occupationally exposed to mouldy tobacco

Work-related respiratory symptoms, including dyspnoea, cough, fever, tiredness and malaise, were recorded in two customs officers employed in 2 depositories of confiscated cigarettes, of which one showed signs of dampness. Microbiological sampling of the air and the cigarettes stored in a damp depository revealed the presence of potentially pathogenic fungi and bacteria and the biochemical markers of bacterial lipopolysaccharide and fungal biomass. The Penicillium species (P. simplicissimum, P. inflatum, P. commune) dominated in the damp depository, while in the other one Aspergillus fumigatus was prevalent. The patients under study did not show a specific sensitization to microbial allergens in the precipitin test, the test for inhibition of leukocyte migration and the bronchial provocation challenge, except for a weak reaction to fungal allergens in the test for inhibition of leukocyte migration. Moreover, one patient responded with subjective symptoms after exposure to inhalation of increased doses of Penicillium simplicissimum antigen. Both cases were diagnosed as a specific form of organic dust toxic syndrome (ODTS). It is hypothesized that the symptoms were evoked most probably by the non-specific action of low molecular fungal metabolites, such as mycotoxins or VOCs (volatile organic compounds), with the possible contribution of bacterial endotoxin. However, as there is no a direct proof to support this presumption, and the effects of nicotine and other tobacco constituents cannot be excluded, further studies are needed to elucidate etiopathogenesis of the disorders associated with the exposure to stored tobacco.

Health effects of exposure to organic dust in workers of a modern hatchery

The aim of the presented study was to determine the health status of workers occupationally exposed to moderate amounts of organic dust, employed in a modern hatchery with an efficient ventilation system. A group of 32 hatchery workers was examined. As a reference group, 50 urban dwellers not exposed to any kind of organic dust were examined. All people were interviewed for the presence of work-related symptoms and subjected to physical and spirometric examinations. Blood sera were examined for the presence of precipitins against 13 antigens associated with organic dust, and for the presence of total and chicken-specific No significant differences were found between the spirometric values in the group of hatchery workers and the reference group. Positive precipitin reactions were noted mostly with the antigens of Gram-negative bacteria associated with organic dust. The frequencies of positive reactions to antigens of Escherichia coli and Acinetobacter baumannii in hatchery workers were significantly greater compared to the reference group (p<0.05). Precipitin reactions to Gram-positive non-branching bacteria, actinomycetes, fungi and birdactions to antigens of Escherichia coli and Acinetobacter baumannii in hatchery workers were significantly greater compared to the reference group (p<0.05). Precipitin reactions to Gram-positive non-branching bacteria, actinomycetes, fungi and bird protein, were rare or absent. The mean concentration of total IgE in sera of hatchery workers was nearly 3 times greater compared to the reference group, and the difference proved to be statistically significant (p<0.05). No specific IgE antibodies against chicken feathers were detected in the blood of hatchery workers and referents. In conclusion, the examined hatchery workers showed a moderate frequency of work-related symptoms, no decline in lung function and low reactivity to most microbial and bird protein allergens. These results suggest that the effects of exposure to organic dust in workers of modern hatcheries with an efficient ventilation system are less compared to the workers of poultry farms, such as broiler or egg laying houses.

Prevalence of Anaplasma phagocytophilum in Ixodes ricinus ticks determined by polymerase chain reaction with two pairs of primers detecting 16S rRNA and ankA genes

A total of 684 Ixodes ricinus ticks (321 nymphs, 184 males, and 179 females) were collected by flagging lower vegetation in 6 forest districts located on the territory of Lublin province (eastern Poland). Ticks were examined by polymerase chain reaction (PCR) method for the presence of Anaplasma phagocytophilum DNA with two pairs of primers: EHR521/EHR747 for detecting 16S rRNA gene, and LA6/LA1 for detecting ankA gene. To study the relationship between infection in ticks and people occupationally exposed to tick bite, blood serum samples of 261 forestry workers employed in the same forest districts were examined by immunofluorescence method for the presence of specific antibodies against A. phagocytophilum. A total of 70 ticks out of 684 examined (10.2%) showed the presence of A. phagocytophilum 16S rRNA gene. The prevalence of infection was significantly dependent on tick's stage (chi-square=49.2, p<0.00001) and geographical locality (chi-square=34.4, p<0.00001). The percentage of I. ricinus females infected with A. phagocytophilum (24.6%) was significantly greater compared to males (6.5%) and nymphs (4.4%) (p<0.00001). Only 19 ticks out of 684 examined (2.8%) showed the presence of A. phagocytophilum ankA gene, significantly less compared to 16S rRNA gene (p<0.00001). The prevalence of infection demonstrated by the presence of ankA gene was also significantly dependent on tick's stage (chi-square=23.6, p<0.00001) but not on locality (chi-square=9.8, p=0.082). A significant correlation was found between the presence of A. phagocytophilum 16S rRNA gene in I. ricinus female ticks from the particular forest districts and the serologic response to A. phagocytophilum of forestry workers employed in the same districts (p<0.05). No significant correlation was found between the presence of A. phagocytophilum ankA gene in I. ricinus ticks and serologic response of exposed workers. In conclusion, detection of A. phagocytophilum infection in ticks by PCR with the use of EHR521/EHR747 primers detecting 16S rRNA gene is significantly more sensitive compared to LA6/LA1 primers detecting ankA gene.

Efficacy of a novel biofilter in hatchery sanitation: II. Removal of odorogenous pollutants

The present research assessed the treatment efficiency of odorogenous pollutants in air from a hatchery hall vented on organic and organic-mineral beds of an enclosed-container biofilter. In this study, the following media were used: organic medium containing compost and peat (OM); organic-mineral medium containing bentonite, compost and peat (BM); organic-mineral medium containing halloysite, compost and peat (HM). The concentration of odorogenous gaseous pollutants (sulfur compounds and amines) in the hatching room air and in the air after biotreatment were determined by gas chromatography. In the hatchery hall among the typical odorogenous pollutants, there were determined 2 amines: 2-butanamine and 2-pentanamine, hydrogen sulfide, sulfur dioxide, carbon disulfide, sulfides and mercaptans. Ethyl mercaptan showed the highest levels as its mean concentration in the hatchery hall air exceeded 60 microg/m3 and in single samples even 800 microg/m3. A mean concentration of 2-butanamine and sulfur dioxide in the examined air also appeared to be relatively high--21.405 microg/m3 and 15.279 microg/m3, respectively. In each filter material, the air treatment process ran in a different mode. As the comparison reveals, the mean reduction of odorogenous contaminants recorded in the hall and subjected to biotreatment was satisfying as it surpassed 60% for most established pollutants. These high removal values were confirmed statistically only for single compounds. However, a low removal level was reported for hydrogen sulfide and sulfur dioxide. No reduction was recorded in the bentonite supplemented medium (BM) for sulfur dioxide and methyl mercaptan. In the organic medium (OM) no concentration fall was noted for dipropyl sulfide either. In all the media investigated, the highest removal rate (100%), not confirmed statistically, was observed for carbon disulfide. Very good results were obtained in the medium with a bentonite additive (BM) for both identified amines, whose mean elimination rate exceeded 60% (p<or=0.05). The present research proved that diethyl sulfide is most susceptible to biofiltration (over 80%) in the bed supplemented with halloysite (HM) and bentonite (BM) (p<or=0.05).

Levels of fungi and mycotoxins in the samples of grain and grain dust collected from five various cereal crops in eastern Poland

During combine harvesting of 5 various cereal crops (rye, barley, oats, buckwheat, corn) 24 samples of grain and 24 samples of settled grain dust were collected on farms located in the Lublin province of eastern Poland. The samples were examined for the concentration of total microfungi, Fusarium species, deoxynivalenol (DON), nivalenol (NIV), and ochratoxin A (OTA). Microfungi able to grow on malt agar were present in 79.2% of grain samples and in 91.7% of grain dust samples in the concentrations of 1.0-801.3x10(3) cfu/g and 1.5-12440.0x10(3) cfu/g, respectively. The concentration of microfungi in grain dust samples was significantly greater than in grain samples (p<0.01). Fusarium strains were isolated from 54.2% of grain samples and from 58.3% of grain dust samples in the concentrations of 0.1-375.0x10(3) cfu/g and 4.0-7,700.0x10(3) cfu/g, respectively. They were found in all samples of grain and grain dust from rye, barley and corn, but only in 0-16.7% of samples of grain and grain dust from oats and buckwheat. DON was found in 79.2% of grain samples and in 100% of grain dust samples in the concentrations of 0.001-0.18 microg/g and 0.006-0.283 microg/g, respectively. NIV was detected in 62.5% of grain samples and in 94.4% of grain dust samples in the concentrations of 0.004-0.502 microg/g and 0.005-0.339 microg/g, respectively. OTA was detected in 58.3% of grain samples and in 91.7% of grain dust samples in the concentrations of 0.00039- 0.00195 microg/g and 0.00036-0.00285 microg/g, respectively. The concentrations of DON, total fusariotoxins (DON+NIV) and OTA were significantly greater in grain dust samples than in grain samples (p<0.05, p<0.05, and p<0.001, respectively). The concentration of Fusarium poae in the samples of rye grain and dust was significantly correlated with the concentrations of DON (p<0.05), NIV (p<0.01), and total fusariotoxins (p<0.05). Similarly, the concentration of Fusarium culmorum in the samples of barley grain and dust was significantly correlated with the concentration of total fusariotoxins (p<0.05). A significant correlation was also found between the concentration of total fungi grown on malt agar and the concentration of OTA (p<0.05). In conclusion, although the concentration of DON, NIV and OTA in the samples of grain dust collected from 5 various cereals on farms in eastern Poland was not large, the persistent presence of these mycotoxins in over 90% of examined samples poses a potential health risk of chronic respiratory intoxication for exposed grain farmers.

Levels of bacterial endotoxin in air of animal houses determined with the use of gas chromatography-mass spectrometry and Limulus test

Air samples were collected on glass fibre filters in 22 animal houses and 3 hay storage barns and examined for the presence of bacterial endotoxin with the Limulus (LAL) test and the gas chromatography-tandem mass spectrometry (GC-MSMS) technique, based on detection of 3-hydroxy fatty acids (3-OH-FAs) as chemical markers of the endotoxin lipopolysaccharide. The median concentrations of airborne endotoxin determined with LAL test in poultry houses, sheep sheds, piggeries, cow barns, and horse stables were respectively 62.49 microg/m3, 26.2 microg/m3, 3.8 microg/m3, 1.65 microg/m3, and 1.14 microg/m3, while those determined with the GC-MSMS technique were respectively 1.06 microg/m3, 7.91 microg/m3, 0.2 microg/m3, 0.31 microg/m3, and 1.42 microg/m3. The median concentrations of airborne endotoxin determined with LAL test and GC-MSMS technique in hay storage barns were much smaller, 0.09 microg/m3 and 0.03 microg/m3, respectively. The concentrations of airborne endotoxin (LPS) detected with GC-MSMS method in the air of sheep sheds were significantly greater than in all other examined facilities, while those detected in hay storage barns were significantly smaller than in all other examined facilities (p<0.05). The concentrations of airborne endotoxin determined with LAL test and GC-MSMS analysis exceeded in most of animal houses examined (91% by each method) the threshold limit value for airborne endotoxin of 0.1 microg/m3 proposed by various authors. A significant correlation (p<0.05) between the concentrations of endotoxin determined with the LAL and GC-MSMS techniques was found in the air samples collected in poultry houses and sheep sheds, but not in other examined facilities. 3-OH FAs with C14-C18 chains were predominant in the air of the facilities under study. A significant correlation (p<0.05) was found between the concentrations of endotoxin determined with LAL test and the amounts of 3-OH FAs with C14-C16 chains. In conclusion, endotoxin in the concentrations detected in this study may present a respiratory hazard to both humans and livestock animals.

Efficacy of a novel biofilter in hatchery sanitation: I. Removal of airborne bacteria, dust and endotoxin

A novel biofilter containing organic, bentonite and halloysite media was applied for elimination of microbial pollutants from the air of an industrial hatchery. The concentrations of total mesophilic bacteria, Gram-negative bacteria, thermophilic actinomycetes, dust and bacterial endotoxin were determined in the air of hatchery during 2 months before installation of the biofilter, and during 6 months after installation of the biofilter, at the inlet and outlet ducts from each medium. Before installation of the biofilter, the concentrations of total mesophilic bacteria, Gram-negative bacteria, thermophilic actinomycetes, dust and endotoxin in the air were within the ranges of 0.97-131.2x10(3) cfu/m3, 0.0-34.4x10(3) cfu/m3, 0.0-0.02x10(3) cfu/m3, 0.37-4.53 mg/m3, and 50.9-520,450.4 ng/m3, respectively. Enterococcus faecalis and Gram-negative bacteria (Acinetobacter spp., Escherichia coli, Enterobacter cloacae, and other species) prevailed among bacterial species recovered from the air of the hatchery. A total of 56 species or genera of bacteria were identified in the air samples taken in the examined hatchery; of these, 11, 11 and 6 species or genera respectively were reported as having allergenic, immunotoxic and/or infectious properties The concentrations of total mesophilic bacteria, Gram-negative bacteria, Enterococcus faecalis and endotoxin found at the inlet duct of the biofilter after its installation were significantly smaller compared to those recorded before its installation (p<0.05). The concentrations of Gram-negative bacteria, Enterococcus faecalis and dust found at the outlet ducts of biofilter after its installation were significantly smaller compared to those recorded at the inlet duct of the biofilter (p<0.01). The concentrations of total meso-philic bacteria were also smaller at the outlet ducts of the biofilter compared to that at the inlet duct; however, the difference was not significant because of the massive growth of Streptomyces species in the biofilter's media which contaminated the outcoming air. In conclusion, the applied biofilter proved to be effective in the elimination of potentially pathogenic bacteria, dust and endotoxin from the air of the hatchery. The efficacy of the biofilter could be improved by the inhibition of the Streptomyces growth in the media of the biofilter.

Transmission electron microscopy studies of microstructure of Ti-Nb and Ti-Ta alloys after ball milling and hot consolidation

Two Ti alloys with compositions Ti-10Ta and Ti-10Nb (at.%) were milled in a high-energy mill for a maximum of 80 h in an argon atmosphere. A nanocrystalline structure of alpha-Ti(X) (X = Ta or Nb) solid solution was formed in both investigated alloys after milling, as shown by X-ray diffraction. Transmission electron microscopy observations of powders milled for 80 h revealed chemical inhomogeneity of particles in nanometre-scale regions and an average crystallite size of about 10 nm. The pulse plasma sintering method was applied for hot consolidation of milled powders. The mean density of pulse plasma sintering compacts of Ti-Nb alloy was about 99.5% of the theoretical value, whereas the density of the Ti-10Ta sample was lower, close to 92% of the theoretical value. Transmission electron microscopy observation of compacted samples showed that the sintering process caused the formation of a two-phase alpha + beta structure in both investigated alloys, with a mean grain size of 220 nm. The chemical inhomogeneity and high degree of deformation in nanometre-scale regions of milled powders led to a martensitic transformation, resulting in formation of a 9R martensite structure.

Structure studies of ball-milled ZrCuAl, NiTiZrCu and melt-spun ZrNiTiCuAl alloys

ZrNiTiCu and ZrNiTiCuAl alloys were amorphized using either a melt-spinning or ball-milling process in a high-energy planetary mill. The elemental powders were initially blended to the desired composition (in at.%) of Zr, 65; Cu, 27.5; Al, 7.5 and of Ti, 25; Zr, 17; Cu, 29; Ni, 29, respectively. The composition of alloys was chosen to be the same as for the bulk amorphous ZrCuAl and easy glass-forming ZrNiTiCu alloys. An almost fully amorphous structure was obtained after 80 h of milling in the case of both compositions. Transmission electron microscopy studies of ball-milled powders revealed the presence of nano-crystallites [2-5 nm for ZrCuAl and smaller (1-3 nm) for the ZrTiNiCu alloy]. High-resolution transmission electron microscopy of melt-spun ZrNiTiCuAl ribbons provided evidence of the amorphous structure.

TEM and HREM study of Al3Zr precipitates in an Al-Mg-Si-Zr alloy

The structure of Al(3)Zr precipitates in Al-1.0Mg-0.6Si-0.5Zr (in wt.%) alloy was investigated using conventional transmission electron microscopy (TEM) and high-resolution TEM (HREM). After annealing of the alloy in the temperature range 450-540 degrees C, spherical precipitates of metastable L1(2)-Al(3)Zr phase appeared nearly homogeneously within the matrix, and elongated particles were found at grain boundaries. L1(2)-structured Al(3)Zr were about 20-30 nm in diameter and coherent with the matrix. Inside some of them, planar faults parallel to {100} planes were revealed by use of HREM. Most probably, these faults are an indication of the transition stage of transformation to the stable D0(23)-type Al(3)Zr phase. The elongated precipitates (about 100 nm) were identified as D0(22)-type Al(3)Zr. Energy-dispersive X-ray analysis showed that they contain, apart from Al, mainly Zr with small amounts of Si. The substitution of Al by Si increased the stability of the D0(22)-Al(3)Zr as compared with D0(23)-Al(3)Zr.

Prevalence of Babesia microti in Ixodes ricinus ticks from Lublin region (eastern Poland)

A total of 1,367 Ixodes ricinus ticks collected from 5 districts of the Lublin region (eastern Poland) were examined for the presence of Babesia microti DNA by PCR and nested-PCR. As many as 74 ticks (5.4 %) were found to be infected with Babesia microti. The infection rate varied significantly with stage/sex of ticks (chi (2) =16.48543, df=2, p < 0.000264). The infection rates in females and males amounted to 6.4 % and 8.8 % respectively and were significantly higher (p=0.006 and p=0.0001 respectively) compared to minimum infection rate in nymphs that was equal to 2.8 %. The prevalence of infection showed also a significant variability depending on geographic location within the Lublin region (chi(2) =18.62812, df=4, p < 0.000932). The highest rates of infection with Babesia microti were noted in ticks collected from the areas of Puławy district situated in the northern part of region and the suburban Lublin district situated in the central part of the region (8.0 % and 7.3 % respectively). Mediocre infection rates (respectively 3.4 % and 3.3 %) were found in ticks from the Parczew and Włodawa districts situated in eastern part of the region and covered with humid lakeland forests. The lowest infection rate (0.5 %) was noted in ticks from the Zamość district situated in southern part of the region. In conclusion, the infection rate of Ixodes ricinus ticks with Babesia microti found in this study is higher compared to the majority of data reported by Polish and other European authors, and indicates a potential risk of human infection during occupational or recreational exposure to tick bite.

Correlation of tests for detection of Borrelia burgdorferi sensu lato infection in patients with diagnosed borreliosis

A group of 180 patients with diagnosed Lyme borreliosis were examined for the presence of infection with Borrelia burgdorferi sensu lato (B. burgdorferi s.l.) by serologic tests with B. burgdorferi s.l. antigens (IgM-ELISA, IgG-ELISA, IgM-immunoblot, IgG-immunoblot) and by polymerase chain reaction (PCR, nested-PCR) for detection of B. burgdorferi s.l. DNA in peripheral blood. A total of 61.7 %, 53.9 %, 62.2 %, and 59.4 % of the examined patients' sera showed positive or borderline results in the serologic tests IgM-ELISA, IgG-ELISA, IgM-immunoblot, and IgG immunoblot, respectively. The results of the tests IgM-ELISA and IgM-immunoblot were significantly correlated (p < 0.001). A higher degree of the correlation (p < 0.000001) was found at the comparison of results obtained with IgG-ELISA and IgG-immunoblot. The correlation between the positive findings in the IgM-ELISA and detection with IgM-immunoblot the diagnostically important B. burgdorferi s.l. OspC surface protein was relatively low but statistically significant (0.01 < p < 0.05). Much higher correlation was found between the positive findings in the IgG-ELISA and detection with IgG-immunoblot other diagnostically important B. burgdorferi s.l. antigen, the VlsE protein (p < 0.000001). The presence of B. burgdorferi s.l. DNA was found by PCR in 20 out 180 examined blood samples (11.1 %). No correlation was found to exist between the PCR results and the results of any of the serologic tests for detection of anti B. burgdorferi s.l. antibodies of IgM class. PCR results correlated significantly at a relatively low level (0.01 < p < 0.05) with the results of IgG-ELISA, but not with the results of IgG-immunoblot with regard to total reactions (0.2 < p < 0.1). By contrast, a distinctly significant correlation was found between the PCR results and detection of the VlsE protein with IgG-immunoblot (0.001 < p < 0.01). In conclusion, the results of the present study suggest that antibodies of IgG class are the most reliable marker in laboratory diagnostics of Lyme borreliosis, in particular those directed against VlsE surface protein of Borrelia burgdorferi sensu lato.

Variability of airborne microflora in a hospital ward within a period of one year

The aim of the study was to determine the seasonal variability of the airborne microflora in a hospital ward of the pneumonological department, with regard to potential impact on respiratory status of asthmatic patients hospitalized in the ward. Microbiological air sampling was carried out for a period of 1 year from June-May, during work-days, 16-21 days per month. Each day, the air samples were collected twice: in the morning at 09:00 and in the afternoon at 13:00. Air samples were taken with a custom-designed particle-sizing slit sampler enabling estimations of both total and respirable fractions of the microbial aerosol. Air samples for determination of bacteria were taken on blood agar and air samples for determination of fungi were taken on Sabouraud agar. Mean monthly concentrations of total microorganisms (bacteria + fungi) in the air of the examined hospital ward were between 296.1-529.9 cfu/m3. Mean monthly concentrations of airborne bacteria ranged from 257.1-436.3 cfu/m3, with peak values in November and May and the lowest values from December to February. Mean monthly concentrations of airborne fungi showed much greater variation than bacteria and ranged from 9.9-96.1 cfu/m3 with the very distinct peak in November and the lowest value in May. The variations in monthly concentrations of total microorganisms, bacteria and fungi in the air of hospital ward were statistically significant (p < 0.001). The concentrations of total airborne microorganisms, bacteria and fungi recorded in the hospital in the morning were significantly greater compared to those recorded in the afternoon (p < 0.01). The mean monthly values of respirable fraction for total microorganisms were within a range of 17.3-44.4%, for bacteria within a range of 17.2-44.8%, and for fungi within a range of 2.2-39.1%. The most common microorganisms in the air of the examined ward were Gram-positive cocci which accounted for 31.4-46.4% of the total count. Gram-negative bacteria and corynebacteria were less numerous, forming respectively 11.8-27.5% and 9.6-20.0% of the total count. Endospore-forming bacilli and actinomycetes occurred in small proportions, respectively 0.3-3.2% and 0-2.0% of the total count. Fungi formed 7.6-42.5% of the total count. The prevailing species was Aspergillus fumigatus which constituted on average 77.0% of total fungal strains isolated from the air of the hospital ward. A significant decrease of spirographic indices (VC, FEV1) in asthmatic patients hospitalized in the ward, at increase of the concentration of airborne bacteria and/or fungi, was found in 9 out of 24 examined patients (37.5%) and in 19 out of 192 analysed single relationships (9.9%). In conclusion, although bacteria and fungi occurred in the air of the examined hospital ward in relatively low numbers (of the order 10(2) cfu/m3 and 10(1) cfu/m3 respectively), they should be considered as a possible cause of asthma exacerbations in some patients because of the presence of Aspergillus fumigatus and other potentially pathogenic species.

Prevalence of Borrelia burgdorferi genospecies in Ixodes ricinus ticks from Lublin region (eastern Poland)

The objective of the study was to determine the prevalence rate of 3 Borrelia burgdorferi genospecies in Ixodes ricinus ticks collected from wooded areas of the Lublin region (eastern Poland). A group of 1,813 I. ricinus ticks from 6 districts were examined for the presence of Borrelia burgdorferi sensu lato (B.b.s.l.) by polymerase chain reaction (PCR). Another group of 438 I. ricinus ticks collected from 4 districts were examined for the presence of B.b.s.l. by culture on BSKH liquid medium confirmed by PCR, and for the presence of Borrelia spp. by dark field microscopy (DFM). Borrelia burgdorferi genospecies (Borrelia burgdorferi sensu stricto, Borrelia afzelii and Borrelia garinii) were determined by nested-PCR in 113 ticks lysates showing presence of B.b.s.l. (in PCR or in culture and PCR). 5.4 % of I. ricinus ticks examined by PCR showed the presence of B.b.s.l. DNA. The infection rate was highest in females (12.1 %), lower in males (6.0 %) and the lowest in nymphs (1.7 %) (p < 0.001). The minimum infection rate of I. ricinus ticks with B.b.s.l. determined by culture was 3.4 %, whereas the minimum infection rate of ticks with motile spirochetes morphologically resembling Borrelia spp., determined by DFM, amounted to 11.2 %. The presence of all 3 Borrelia burgdorferi genospecies under investigation was found in ticks collected from 5 out of 6 examined districts. In 81.4 % of infected ticks only single infection with 1 genospecies was observed, while coinfections with 2 or 3 genospecies were detected respectively in 16.8 % and 1.8 % of infected ticks. Borrelia burgdorferi sensu stricto was the dominant genospecies in all examined tick stages and districts, both in single infections and in coinfections, and found in a total of 62.8 % of I. ricinus ticks infected with B.b.s.l. Borrelia afzelii and Borrelia garinii were less frequent and observed in respectively 39.8 % and 17.8 % of infected ticks.

Occurrence of Toxoplasma gondii in water from wells located on farms

Among various species of parasitic protozoans which may contaminate drinking water, Toxoplasma gondii is of a special importance due to the high incidence of infections with this parasite noted in animals and humans. The objective of this study was to determine the frequency of occurrence of T. gondii in drinking water on farms in the area of the Lublin province (eastern Poland) with respect to health risk among the inhabitants, and to assess the role of water in the transmission of Toxoplasma infections in the rural environment. Studies were conducted on 87 farms located in the Lublin province, 14 of which were classified as possessing a good hygienic state, and 73 as possessing a poor hygienic state. A total number of 114 drinking water samples were taken, 80 samples from shallow household wells with a windlass, 16 from deep wells with a pump, and 18 from the water supply system. In microscopic and PCR examinations of 114 water samples, T. gondii was found in 15 (13.2%) and 31 (27.2%) of samples, respectively. The presence of T. gondii DNA detected by PCR test was found significantly more frequently in water samples from the shallow windlass-operated wells than in those from deep wells (p < 0.05) and water supply system (p < 0.01). Water samples collected from shallow wells located on farms of poor hygienic state contained significantly more frequently DNA of T. gondii than samples from shallow wells located on farms of good hygienic state (43.1% vs. 13.3%, p < 0.05). In 26.3% of water samples, oocysts of other protozoans were found belonging to Isospora, Eimeria, and Cryptosporidium. Serologic examinations for the presence of anti-Toxoplasma antibodies conducted among 99 inhabitants of the farms where household wells were used showed 64.6% of seropositive results in IgG class antibodies and 1.0% in IgM class antibodies. Clinical cases of toxoplasmosis were also noted. In the total population examined, a positive correlation was observed between the consumption of unboiled well water and the presence of antibodies against T. gondii (p < 0.05), this correlation being especially strong on farms of poor hygienic state enclosing shallow wells (p < 0.001). In conclusion, the recorded presence of T. gondii in well water provides an evidence of the potential risk of waterborne infection for humans and animals. Therefore, it seems necessary to implement prophylactic actions on the endangered farms.

Legionella and other gram-negative bacteria in potable water from various rural and urban sources

A total of 107 potable water samples were collected from various rural and urban sources located in the Lublin region (eastern Poland). 54 samples from rural sources comprised 32 samples of untreated well water and 22 samples of treated (chlorinated) tap water from rural dwellings distributed by the municipal water supply system (MWSS). 53 samples of treated water from urban sources were supplied by the city of Lublin MWSS. They comprised: 11 samples of tap water from offices and shops, 8 samples of tap water from dwellings, 19 samples from showerheads in health care units, and 15 samples from the outlets of medical appliances used for hydrotherapy in a rehabilitation centre. Water samples were examined for the presence and species composition of Legionella, Yersinia, Gram-negative bacteria belonging to family Enterobacteriaceae (GNB-E) and Gram-negative bacteria not belonging to family Enterobacteriaceae (GNB-NE), by filtering through cellulose filters and culture on respectively GVPC, CIN, EMB and tryptic soya agar media. Legionella was recovered from samples of well water, tap water from rural dwellings, tap water from urban dwellings, and water from medical appliances - with the isolation frequency of 27.8-50.0 %, and the low concentrations ranging from 0.7-13.3 x 10 (1) cfu/l. No Legionella strains were detected in tap water from offices and shops, and in water from showerheads in health care units. Strains of the Legionella pneumophila types 2-14 predominated, forming 89.9 % of total Legionella isolates, while other species of Legionella formed 10.1 %. Neither Legionella pneumophila type 1 strains nor Yersinia strains were isolated from the examined water samples. The isolation frequency and mean concentration of GNB-E in water samples from rural sources was significantly greater than in water samples from urban sources (respectively 61.1 % vs. 20.8 %, 17.1 vs. 3.4 x 10(1) cfu/l, p < 0.001). Isolation frequency of GNB-NE in water samples from rural sources was significantly greater compared to that from urban sources (77.8 % vs. 47.2 %, p < 0.01), but there was no significant difference in the concentration of GNB-NE in both sample sets. A significant correlation was found between concentrations of Legionella and GNB-NE for total MWSS water samples (p < 0.001), but not for the total well water samples. Altogether 34 GNB-E and GNB-NE species and/or genera were identified in the examined samples, out of which 21 were potentially pathogenic. Enterobacter spp., Klebsiella spp., Serratia spp., and Pantoea agglomerans were most common among GNB-E, while Acinetobacter spp. and species of Pseudomonadaceae family predominated among GNB-NE.