Zbigniew Mudryk

Detection of antibiotic resistant bacteria inhabiting the sand of non-recreational marine beach.

The present study examined the antibiotic resistance of heterotrophic bacteria, which were isolated from the sand of the beach located in the National Park of the southern Baltic Sea coast. The bacteria demonstrated low levels of antibiotic resistance. These microorganisms were the most resistant to cefaclor and clindamycin and the most sensitive to clarithromycin, doxycycline, gentamycin and oxytetracycline. The majority of bacteria inhabiting the sand of the studied beach were resistant to only one antibiotic out of 18 tested antibiotics in this study. The bacteria inhabiting the middle part of the beach and the dune were more antibiotic resistant than bacteria isolated from the seawater and the shoreline-seawater contact zone. Generally, there was no significant difference in antibiotic resistance between bacteria isolated from the surface and the subsurface sand layers. The bacterial antibiotic resistance level depends on the chemical structure of antibiotics.

In vitro antibiotic resistance of Vibrio-like organisms isolated from seawater and sand of marine recreation beach in the southern Baltic Sea.

Vibrio-like bacteria (VLO) were isolated from the seawater and sand of marine recreation beach located on the southern coast of the Baltic Sea and their antibiotic resistance was studied. According to susceptibility test, planktonic, and benthic VLO were the most resistant to β-lactam (ampicillin and penicillin) and lincosamide (clindamycin) antibiotics, while the most susceptible to tetracycline and aminoglycosides (gentamycin). Moreover the results showed that Vibrio-like bacteria inhabiting sand were more antibiotic-resistant than those isolated from seawater. In general, there was no difference in antibiotic resistance between VLO isolated from the surface and subsurface sand layers. More than 90% of planktonic and benthic Vibrio-like bacteria showed multiple antibiotic resistance.

A relationship between accumulation of heavy metals and microbiological parameters in the surface microlayer and subsurface water of a coastal Baltic lake

The present study investigated the relationship between accumulations of heavy metals and the concentration of chlorophyll, as well as the number, secondary production and enzymatic activity of bacteria in the surface microlayer (SML) and subsurface waters of a coastal Baltic lake. Concentration of heavy metals was measured by mass spectrometry, chlorophyll by spectrophotometry, bacteria abundance by DAPI staining, secondary production by 3H-thymidine incorporation into DNA and enzymatic activities using fluorescence-labelled substrate methods. Concentrations of all the analysed heavy metals, chlorophyll, as well as the number of heterotrophic bacteria and the level of enzymatic activity were higher in the SML than in subsurface water. No differences in the total number of bacteria in both the studied layers were noted. The rate of secondary production of planktonic bacteria was found to be higher than that of neustonic bacteria. Seasonal variability was observed in the studied chemical and microbiological parameters. It was found that in SML heavy metal concentrations increased in relation to those in subsurface water. However, this did not reduce the level of chlorophyll, heterotrophic bacteria, or the enzymatic activity. In contrast, increased heavy metal concentrations in SML reduced total number of bacteria and the level of secondary productivity.

Activity of extracellular enzymes on the marine beach differing in the level of antropopressure

The level of activity of extracellular enzymes was determined on two transects characterised by different anthropic pressure on a sandy beach in Ustka, the southern coast of the Baltic Sea. Generally, the level of activity of the studied enzymes was higher on the transect characterised by high anthropic pressure. The ranking order of the mean enzyme activity rates in the sand was as follows: lipase > phosphatase > aminopeptidase > β-glucosidase > α-glucosidase > chitinase. Each enzyme had its characteristic horizontal profile of activity. The levels of activity of the studied enzymes were slightly higher in the surface than subsurface sand layer. Extracellular enzymatic activities were strongly influenced by the season.

Abundance and distribution of fecal indicator bacteria in recreational beach sand in the southern Baltic Sea

Se estimo la densidad y la distribucion de indicadores bacterianos fecales en arena seca y humeda y en el agua de mar adyacente de una playa marina recreacional de Polonia en el Mar Baltico. El numero de coliformes totales, coliformes fecales y estreptococos fecales fueron entre 3 y 9 veces mayores en la arena seca que en el agua de mar y entre 2 y 6 veces mayores en arena seca que en arena humeda. Dentro de un ano, el numero de bacterias fecales que habitaron la arena y el agua de mar mostraron considerables cambios mensuales. El mayor numero de indicadores de bacterias fecales en el agua de mar y en la arena aparecieron en la estacion de primavera-verano y el mejor estado sanitario se detecto en los meses de invierno. Hubo diferencias en el numero de indicadores de bacterias fecales entre la capa de arena superficial y subsuperficial, con una clara tendencia decreciente en el numero de las bacterias estudiadas al aumentar la profundidad.

Studies concerning heterotrophic bacteria decomposing macromolecular compounds at two marine beaches

The potential capability to decompose macromolecular compounds was confirmed in heterotrophic bacteria isolated from two sandy beaches located on the southern Baltic coast. Proteolytic bacteria were the most numerous group, whereas lipolytic organisms were rare among bacteria inhabiting the studied beaches. All studied physiological groups of bacteria were considerably more numerous in the sand of the beach subject to stronger anthropopressure. The differences in bacteriological parameters across the horizontal profile of the beaches were noted. In both studied beaches a higher number of bacteria able to decompose macromolecular compounds were recorded in the surface as compared to the subsurface sand layer.

Antibiotic resistance of Staphylococcus-like organisms isolated from a recreational sea beach on the southern coast of the Baltic Sea as one of the consequences of anthropogenic pressure

Antibiotic resistance of Staphylococcus-like organisms (STLO) isolated from a recreational sea beach located on the southern coast of the Baltic Sea was studied. The results of the present study showed that STLO inhabiting sand and seawater of the beach strongly differed in the resistance level to tested antibiotics. These microorganisms were most resistant to ampicillin, penicillin, oxytetracycline and susceptible to gentamicin, neomycin and streptomycin. Moreover, the level of antibiotic resistance among bacteria isolated from different parts of the beach also differed. Bacteria inhabiting the seawater, shoreline and the middle part of the beach were more antibiotic-resistant than bacteria isolated from the dune. The majority of bacteria inhabiting the seawater and sand were resistant to 3–8 antibiotics out of 12 tested in this study. Generally, there was no difference in antibiotic resistance between Staphylococcus-like organisms isolated from the surface and subsurface sand layers. STLO strains isolated from Ustka Beach were most resistant to β-lactam and tetracycline antibiotics, and most susceptible to aminoglycosides.

Effect of sodium chloride on the metabolic activity of halophilic bacteria isolated from the Lake Gardno estuary

The effect of different concentrations of sodium chloride on the metabolic activity of halophilic bacteria derived from the Lake Gardno estuary was studied using respirometric methods. The influence of salt was examined in two ways: the bacteria were preincubated in various concentrations of sodium chloride, and the cells used for respirometric measurements were supplied with substrates dissolved in water amended with various concentrations of the salt. Generally, an increase in the concentration of sodium chloride in the medium used for preincubation resulted in an increase in metabolic activity. Conversely, a decrease was noted when solutions of increasing salt content were employed to dissolve the substrate. The decrease in oxygen uptake noted when increased amounts of salt were added is proposed to be the result of the short period allowed for adaptation of cells to the higher salt concentrations.

Number of bacteria decomposing organic phosphorus compounds and phosphatase activity in the sand of two marine beaches differing in the level of anthropopressure

Number of heterotrophic bacteria ability to decompose organic phosphorus compounds and the level of phosphatase activity in the sand of two marine beaches (southern coast of the Baltic Sea) differing in the level of anthropopressure were studied. The study showed that the number of bacteria and level phosphatase activity were higher in the sand of the beach subjected to stronger anthropopressure. In both studied beaches bacteria hydrolysing DNA were the most numerous (92.7-302.8 CFU·g(-1) d.w.). The least numerous were phytin (26.0·10(3) CFU·g(-1) d.w.) and phenolphthalein diphosphate (11.1·10(3) CFU·g(-1) d.w.) decomposing bacteria. Number of bacteria able to attack tested organic phosphorus compounds were the most numerous in dry zones (10.77-739.92 CFU·g(-1) d.w.) then wet zones (3.34-218.15 CFU·g(-1) d.w.). In both studied beaches bacteria hydrolysing organic phosphorus compounds and phosphatase activity generally were more numerous in surface sand layer. Seasonal variation in the occurrence of bacteria in both studied beaches was observed.

Occurrence of potentially human pathogenic bacteria in the seawater and in the sand of the recreational coastal beach in the southern Baltic Sea

The occurrence and the distribution of potentially human pathogenic bacteria such as Aeromonas, Pseudomonas aeruoginosa, Staphylococcus and Vibrio-like organisms in the sand and the adjacent seawater of the recreational coastal beach were studied. The highest mean number among these four studied groups of bacteria was represented by Aeromonas-like organisms and the lowest one by Staphylococcus-like organisms. Dry sand was inhabited by the highest number of all studied potentially pathogenic bacteria. Within a year, the number of the studied bacteria inhabiting the sand and the seawater showed considerable monthly changes. There were differences in the abundance of potentially pathogenic bacteria between the surface and the subsurface sand layers with a clear decrease in their number toward the deeper layers of the sand.