Publications by authors named "Edina Szekeres"

When antimicrobial resistant bacteria (ARB) and genes (ARGs) reach novel habitats, they can become part of the habitat's microbiome in the long term if they are able to overcome the habitat's biotic resilience towards immigration. This process should become more difficult with increasing biodiversity, as exploitable niches in a given habitat are reduced for immigrants when more diverse competitors are present. Consequently, microbial diversity could provide a natural barrier towards antimicrobial resistance by reducing the persistence time of immigrating ARB and ARG.

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River microbial communities regularly act as the first barrier of defense against the spread of antimicrobial resistance genes (ARGs) that enter environmental microbiomes through wastewater. However, how the invasion dynamics of wastewater-borne ARGs into river biofilm communities will shift due to climate change with increasing average and peak temperatures remains unknown. Here, we aimed to elucidate the effects of increasing temperatures on the naturally occurring river biofilm resistome, as well as the invasion success of foreign ARGs entering through wastewater.

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Background: The extremely halophilic archaeon Haloferax (Hfx.) alexandrinus DSM 27206 was previously documented for the ability to biosynthesize silver nanoparticles while mechanisms underlying its silver tolerance were overlooked. In the current study, we aimed to assess the transcriptional response of this haloarchaeon to varying concentrations of silver, seeking a comprehensive understanding of the molecular determinants underpinning its heavy metal tolerance.

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Article Synopsis
  • Karst aquifers are crucial sources of drinking water but are vulnerable to contamination due to their porous nature; this study investigates the stable core microbiome in karst springs in Romania over one year.
  • Researchers used advanced techniques, including 16S rRNA gene sequencing and antibiotic resistance gene quantification, to identify a consistent bacterial community mainly consisting of Pseudomonadota, Bacteroidota, and Actinomycetota, many of which showed signs of contamination with fecal bacteria and pathogens.
  • The study also found high levels of antibiotic resistance genes linked to various pollutants and proposed specific bacterial groups as potential indicators for monitoring pollution in these sensitive water sources.
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In freshwater systems, cyanobacteria are strong competitors under enhanced temperature and eutrophic conditions. Understanding their adaptive and evolutionary potential to multiple environmental states allows us to accurately predict their response to future conditions. To better understand if the combined impacts of temperature and nutrient limitation could suppress the cyanobacterial blooms, a single strain of Microcystis aeruginosa was inoculated into natural phytoplankton communities with different nutrient conditions: oligotrophic, eutrophic and eutrophic with the addition of bentophos.

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As a consequence of global demographic challenges, both the artificial and the natural environment are increasingly impacted by contaminants of emerging concern, such as bacterial pathogens and their antibiotic resistance genes (ARGs). The aim of this study was to determine the extent to which anthropogenic contamination contributes to the spread of antibiotic resistant enterococci in aquatic compartments and to explore genetic relationships among strains. Antimicrobial susceptibility testing (ampicillin, imipenem, norfloxacin, gentamycin, vancomycin, erythromycin, tetracycline, trimethoprim-sulfamethoxazole) of 574 isolates showed different rates of phenotypic resistance in bacteria from wastewaters (91.

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The spatiotemporal variation of several carbapenemase-encoding genes (CRGs) was investigated in the influent and effluent of municipal WWTPs, with or without hospital sewage input. Correlations among gene abundances, bacterial community composition, and wastewater quality parameters were tested to identify possible predictors of CRGs presence. Also, the possible role of wastewaters in mirroring clinical resistance is discussed.

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Carbapenemase-producing (CPKP) isolated from influent (I) and effluent (E) of two wastewater treatment plants, with (S1) or without (S2) hospital contribution, were investigated. The strains belonged to the Kp1 phylogroup, their highest frequency being observed in S1, followed by S2. The phenotypic and genotypic hypervirulence tests were negative for all the strains tested.

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Selection and dissemination of resistant bacteria and antibiotic resistance genes (ARGs) require a deeper understanding since antibiotics are permanently released to the environment. The objective of this paper was to evaluate the phenotypic resistance of 499 isolates of Pseudomonas spp. from urban water sources, and the prevalence of 20 ARGs within those isolates.

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An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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A mud volcano (MV) is a naturally hydrocarbon-spiked environment, as indicated by the presence of various quantities of PAHs and aromatic isotopic shifts in its sediments. Recurrent expulsion of various hydrocarbons consolidates the growth of hydrocarbonoclastic bacterial communities in the areas around MVs. In addition to the widely-known availability of biologically malleable alkanes, MVs can represent hotbeds of polyaromatic hydrocarbons (PAHs), as well - an aspect that has not been previously explored.

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Ursu Lake is located in the Middle Miocene salt deposit of Central Romania. It is stratified, and the water column has three distinct water masses: an upper freshwater-to-moderately saline stratum (0-3 m), an intermediate stratum exhibiting a steep halocline (3-3.5 m), and a lower hypersaline stratum (4 m and below) that is euxinic (i.

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Cyanobacterial scums at the surface of the lakes are potentially harmful phenomena with increasing occurrence in the last decades, and the causes that lead to their formation are still an unresolved issue. In order to better understand what triggers the scums, we investigated the effect of several Mg and Ca ion concentrations in promoting them in eight Microcystis aeruginosa strains. The possibility to prevent scum formation by using the ion chelator EDTA was also explored.

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The aim of this paper is to describe a new variant of Janthinobacterium lividum - ROICE173, isolated from Antarctic snow, and to investigate the antimicrobial effect of the crude bacterial extract against 200 multi-drug resistant (MDR) bacteria of both clinical and environmental origin, displaying various antibiotic resistance patterns. ROICE173 is extremotolerant, grows at high pH (5.5-9.

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Groundwater is an essential public and drinking water supply and its protection is a goal for global policies. Here, we investigated the presence and prevalence of antibiotic residues, antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), and microbial contamination in groundwater environments at various distances from urban areas. Antibiotic concentrations ranged from below detection limit to 917 ng/L, being trimethoprim, macrolide, and sulfonamide the most abundant antibiotic classes.

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This report describes the biodiversity and ecology of microbial mats developed in thermal gradients (20 to 65°C) in the surroundings of three drillings (Chiraleu [CH], Ciocaia [CI], and Mihai Bravu [MB]) tapping a hyperthermal aquifer in Romania. Using a metabarcoding approach, 16S rRNA genes were sequenced from both DNA and RNA transcripts (cDNA) and compared. The relationships between the microbial diversity and the physicochemical factors were explored.

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Present-day terrestrial analogue sites are crucial ground truth proxies for studying life in geochemical conditions close to those assumed to be present on early Earth or inferred to exist on other celestial bodies (e.g. Mars, Europa).

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A limited number of studies have investigated the biodiversity in deep continental hyperthermal aquifers and its influencing factors. Here, we present the first description of microbial communities inhabiting the Pannonian and Triassic hyperthermal aquifers from the Western Plain of Romania, the first one being considered a deposit of "fossilized waters," while the latter is embedded in the hydrological cycle due to natural refilling. The 11 investigated drillings have an open interval between 952 and 3432 m below the surface, with collected water temperatures ranging between 47 and 104 °C, these being the first microbial communities characterized in deep continental water deposits with outflow temperatures exceeding 80 °C.

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Antimicrobial resistance represents a growing and significant public health threat, which requires a global response to develop effective strategies and mitigate the emergence and spread of this phenomenon in clinical and environmental settings. We investigated, therefore, the occurrence and abundance of several antibiotics and antibiotic resistance genes (ARGs), as well as bacterial community composition in wastewater effluents from different hospitals located in the Cluj County, Romania. Antibiotic concentrations ranged between 3.

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This study investigates the role of coliforms in the carriage of class 1 integron and biocide resistance genes in a drinking water treatment plant and explores the relationship between the carriage of such genes and the biofouling abilities of the strain. The high incidence of class 1 integron and biocide resistance genes (33.3 % of the isolates) highlights the inherent risk of genetic contamination posed by coliform populations during drinking water treatment.

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Synechococcus sp. PCC 7002 is known to be tolerant to most of the environmental factors in natural habitats of Cyanobacteria. Gene expression can be easily studied in this cyanobacterium, as its complete genome sequence is available.

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