Katarzyna Wolny-Koładka

The Effect of Heavy Metal Concentration and Soil pH on the Abundance of Selected Microbial Groups Within ArcelorMittal Poland Steelworks in Cracow

The present study aimed to identify the effect of heavy metal concentration and soil pH on the abundance of the selected soil microorganisms within ArcelorMittal Poland steelworks, Cracow. The analysis included 20 soil samples, where the concentration of Fe, Zn, Cd, Pb, Ni, Cu, Mn, Cr and soil pH were evaluated together with the number of mesophilic bacteria, fungi, Actinomycetes and Azotobacter spp. In the majority of samples soil pH was alkaline. The limits of heavy metals exceeded in eight samples and in one sample, the concentration of Zn exceeded 31-fold. Chromium was the element which most significantly limited the number of bacteria and Actinomycetes.

Silver nanoparticles toxicity against airborne strains of Staphylococcus spp.

ABSTRACT The aim of this study was to explore the toxicity of silver nanoparticles (AgNPs) synthesized by chemical reduction method assessment with regard to airborne strains of Staphylococcus spp. The first step of the experiment was the preparation of silver nanoparticle suspension. The suspension was obtained by a fast and simple chemical method involving the reduction of silver ions through a reducing factor in the presence of the suitable stabilizer required to prevent the aggregation. In the second stage, varied instrumental techniques were used for the analysis and characterization of the obtained nanostructures. Third, the bacteria of the Staphylococcus genus were isolated from the air under stable conditions with 47 sports and recreational horses, relatively. Next, isolated strains were identified using biochemical and spectrophotometric methods. The final step was the evaluation of the Staphylococcus genus sensitivity to nanosilver using the disk diffusion test. It has been proven that prepared silver nanoparticles exhibit strong antibacterial properties. The minimum inhibitory concentration for tested isolates was 30 μg/mL. It has been found that the sensitivity of Staphylococcus spp. isolated from six identified species differs considerably. The size distribution of bacterial growth inhibition zones indicates that resistance to various nanosilver concentrations is an individual strain feature, and has no connection with belonging to a specific species.

Phenotypic and molecular assessment of antimicrobial resistance profile of airborne Staphylococcus spp. isolated from flats in Kraków

Bacteria of the genus Staphylococcus were isolated from air sampled from living spaces in Kraków (Poland). In total, 55 strains belonging to the genus Staphylococcus were isolated from 45 sites, and 13 species of coagulase-negative staphylococci were identified. The species composition of studied airborne microbiota contains Staphylococcus species that are rarely infectious to humans. Most commonly isolated species comprised S. hominis and S. warneri. The disk-diffusion tests showed that the collected isolates were most frequently resistant to erythromycin. The PCR technique was employed to search for genes conferring the resistance in staphylococci to antibiotics from the group of macrolides, lincosamides and streptogramins. The analyzed Staphylococcus isolates possessed simultaneously 4 different resistance genes. The molecular analysis with the use of specific primers allowed to determine the most prevalent gene which is mphC, responsible for the resistance to macrolides and for the enzymatic inactivation of the drug by phosphotransferase. The second most often detected gene was msrA1, which confers the resistance of staphylococci to macrolides and is responsible for active pumping of antimicrobial particles out of bacterial cells.

Species composition and molecular assessment of the toxigenic potential in the population of Fusarium spp. isolated from ears of winter wheat in southern Poland

The aim of this study was to identify the species composition and to evaluate the prevalence of genes involved in the synthesis of the following mycotoxins: deoxynivalenol, nivalenol and fumonisins in the population of Fusarium spp. isolated from ears of winter wheat in southern Poland. All fungal isolates were identified by the species-specific PCR or sequencing of the translation elongation factor. Significant differences were observed in both abundance and species composition of the collected strains between two years of studies. A total of 304 ear samples were processed and 107 Fusarium strains belonging to 10 species: F. graminearum , F. culmorum , F. sporotrichioides , F. poae , F. avenaceum , F. oxysporum , F. verticillioides , F. equiseti , F. tricinctum and F. cerealis were isolated in 2012 and 2013. Numerous presence of mycotoxin-biosynthesis pathway genes was detected in the examined material, which evidences the potential toxicity of the analyzed Fusarium fungi.

In vitro effects of various xenobiotics on Fusarium spp. strains isolated from cereals

This study aimed to determine the susceptibility of Fusarium spp. strains isolated from cereals to selected heavy metals, fungicides and silver nanoparticles. The experiments were conducted using 50 Fusarium strains belonging to five species: F. graminearum, F. culmorum, F. oxysporum, F. sporotrichioides and F. avenaceum. The strains were found to be highly resistant to Pb2+ and Zn2+. Medium resistance to Cu2+ and Mn2+ and low resistance to Cd2+ and Fe3+ was also observed. Among the tested fungicides, formulations containing azoxystrobin, prochloraz and tebuconazole proved to be the most effective in inhibiting the growth of fungi, as they affected fungal growth in each of the applied doses. Susceptibility of Fusarium spp. to nanosilver, demonstrated in this study, shows the legitimacy of using nanostructures as fungicidal agents. The results confirm high diversity of the analyzed fungal species in terms of susceptibility to the tested substances, and encourage to continue research on the resistance of Fusarium spp. to various fungicidal agents.

The prevalence of selected genes involved in the biosynthesis of trichothecenes assessed with the specific PCR tests in Fusarium spp. isolated from cereals in southern Poland

The analysis was conducted using 50 isolates of fungi of the genus Fusarium belonging to the species classified as major trichothecene mycotoxin producers: F. graminearum, F. culmorum, F. sporotrichioides, and F. poae. The tested fungi were isolated from ears of cereal crops in southern Poland during the two growing seasons (2011 and 2012). The aim of this study was to evaluate the prevalence of genes involved in the biosynthesis of trichothecene mycotoxins using the specific PCR tests. Molecular analyses indicated that the genes responsible for the production of trichothecenes (Tri3, Tri5, Tri7, Tri13) were abundant in the examined genetic material. The tested fungal isolates were characterized by a large diversity in terms of the number and composition of the possessed Tri genes. On the other hand, 14 of 50 isolates were found not to carry any of Tri genes.

The molecular marker-based comparison of Azotobacter spp. populations isolated from industrial soils of Cracow-Nowa Huta steelworks (southern Poland) and the adjacent agricultural soils

The occurrence of Azotobacter spp., which has beneficial effects on plant development, is related to various soil properties, such as pH and fertility. This study evaluated the prevalence of Azotobacter spp. in industrial (H) and agricultural soils (P) in Nowa Huta, Cracow and determined the phenotypic and genetic diversity of these bacteria. The examined bacteria were present in 40% of H and in 50% of P soils. Taxonomic identification of the bacterial isolates indicated the presence of three species—A. salinestris, A. chroococcum and A. vinelandii. The genetic diversity, determined using two fingerprinting methods—Random Analysis of Polymorphic DNA (RAPD) and Rep-PCR (BOX) revealed high level of population diversity. In AMOVA analysis most of diversity was attributed to within-population variation (76–85%), and only 3.78–6.18% was associated with among-group H and P variation. Global test of differences revealed distinct population structure within bacterial strains isolated from H and P areas only for BOX markers (Fst = 0.05732, P = 0.00275). Phenetic analyses: UPGMA and DCA better discriminated H and P groups based on RAPD data. Both BOX and RAPD methods provided an insight into the genetic complexity of Azotobacter spp. variation in soils of different land-use types.

Resistance to Antibiotics and the Occurrence of Genes Responsible for the Development of Methicillin Resistance in Staphylococcus Bacteria Isolated From the Environment of Horse Riding Centers

Abstract The purpose of the study was to identify species, to determine the drug resistance profile, and to evaluate the occurrence of genes responsible for the development of methicillin resistance in Staphylococcus bacteria isolated from the environment of horse riding centers. Staphylococci were isolated from air, manure, and nostrils of horses located in three horse riding centers, differing in horse stabling system—box stall stabling (OJK Pegaz and KJK Szary) and free‐range stabling (SKH Nielepice). The dominant species was Staphylococcus vitulinus. A large variation in the frequency of occurrence of individual species between horse riding centers was determined. Resistance to antibiotics was determined by means of disc diffusion method and polymerase chain reaction technique to detect mecA genes responsible for methicillin resistance. In total, 408 strains were collected, most from SKH Nielepice, and least from OJK Pegaz. The highest resistance was found to gentamicin and tetracycline. Multidrug‐resistant isolates were also detected in KJK Szary (10), in SKH Nielepice (5), and in OJK Pegaz (4). Methicillin resistance determined by disk diffusion assay was found in 23 strains, while the mecA gene was detected in 142 isolates. A total of 137 strains holding the mecA gene are coagulase‐negative staphylococci (CNS), which, as shown by our own studies, may be a reservoir of methicillin resistance. Most commonly, the mecA gene was found in staphylococci isolated in KJK Szary (61.70%). The mecA gene was detected in five strains that belonged to Staphylococcus aureus species and came from horses in SKH Nielepice, indicating the presence of methicillin‐resistant Staphylococcus aureus strains in these animals. HighlightsEvaluation of drug resistance profile of Staphylococcus spp. isolated from horses.Presence of mecA gene in horses.Monitoring the spread of drug resistance among environmental bacteria.

Eco-friendly approach to the synthesis of silver nanoparticles and their antibacterial activity against Staphylococcus spp. and Escherichia coli

ABSTRACT The aim of this study was to assess bactericidal properties of nanosilver obtained with ascorbic acid (vitamin C) as a reducing substance, against environmental strains of Gram-positive (Staphylococcus) and Gram-negative bacteria (Escherichia coli). Silver nanoparticles were obtained by a simple and fast method of chemical reduction in mild synthesis condition using substrates not classified as dangerous and commonly found in plants. Bacterial susceptibility to nanosilver was determined using the disk-diffusion method. Gram-positive bacteria were less susceptible to bactericidal action of nanosilver and minimum inhibitory concentration was higher for these bacteria. However, susceptibility of individual isolates of different species to nanosilver was very diverse. The range of growth inhibition zones indicates that the resistance to different concentrations of nanosilver was a strain-characteristic, not species-related feature. The study of effective nanomaterials synthesis and applicability appears to be an extremely important element in the development of nanotechnology, especially in terms of the risks assessment. Obtained results have a real chance to be an important step toward creating a new generation of disinfectants without toxic effects on the environment and higher organisms.

Ocena toksyczności nanocząstek srebra w stosunku do lekoopornych szczepów Eescherichia coli izolowanych z odpadów

The aim of the study was to evaluate the bactericidal properties of silver nanoparticles against bacteria Escherichia coli. In addition, a sensitivity analysis was made of E. coli to commonly used antibiotics. In the study were used 51 strains isolated from municipal waste. Applied growing concentrations of nanosilver were used: 5, 10, 15, 30, 60 and 125 ppm. The positive control was an antibiotic – ampicillin, negative control – a distilled water. Drug-resistance analysis was performed by disc-diffusion method. Along with the increase in the concentration of silver nanoparticles their antibacterial properties is also growing. The smallest concentration that inhibited growth of some isolates was 5 ppm, while the most effective concentration was 125 ppm. Analysis of drug resistance showed that the antibiotic inhibits growth of a large number of E. coli strains was amikacin. In addition, 22% of all isolates analyzed were drug-resistant. Nanosilver has a high bactericidal potential and may be helpful in solving the problem of drug resistance. However, it is reasonable to conduct further studies on the effects of toxicity of nanoparticles on the environment and higher organisms.