First isolation of carbapenem-resistant Acinetobacter beijerinckii from an environmental sample

The emergence of opportunistic Acinetobacter spp. in healthcare settings poses a significant threat to public health. The major reasons for nosocomial spread of these species are their abilities to develop and transfer drug resistance against various classes of antibiotics. Considering that Acinetobacter spp. are ubiquitous in nature, can utilize several carbon sources, and reach humans via various pathways, our aim was to obtain information about the environmental strains of this genus. Our first step was to develop and test a multistep isolation procedure based on traditional scientific methods. Antibiotic resistance patterns of the isolated strains were determined, as susceptibility to 12 antibiotics of 7 classes was tested by MIC Test Strip method. Altogether 366 samples (groundwater, surface water, and soil) of 24 sites were investigated and a collection of 37 Acinetobacter isolates was obtained. Among others, clinically important human pathogen Acinetobacter spp., such as A. baumannii, A. johnsonii, and A. gyllenbergii were identified. Three environmental strains were determined as multidrug-resistant including a carbapenem-resistant, hemolytic Acinetobacter beijerinckii strain isolated from a hydrocarbon-contaminated groundwater sample. In summary, it has been found that the applied multistep isolation procedure is applicable to isolate various species of Acinetobacter genus. Based on the antibiotic resistance assay, we can conclude that environmental representatives of Acinetobacter spp. are able to develop multidrug resistance, but at a lower rate than their clinical counterparts

Glyphosate and glyphosate-based herbicides (GBHs) induce phenotypic imipenem resistance in Pseudomonas aeruginosa

GBHs are the most widely used herbicides for weed control worldwide that potentially affect microorganisms, but the role of their sublethal exposure in the development of antibiotic resistance of Pseudomonas aeruginosa is still not fully investigated. Here, the effects of glyphosate acid (GLY), five glyphosate-based herbicides (GBHs), and POE(15), a formerly used co-formulant, on susceptibility to imipenem, a potent carbapenem-type antibiotic, in one clinical and four non-clinical environmental P. aeruginosa isolates were studied. Both pre-exposure in broth culture and co-exposure in solid media of the examined P. aeruginosa strains with 0.5% GBHs resulted in a decreased susceptibility to imipenem, while other carbapenems (doripenem and meropenem) retained their effectiveness. Additionally, the microdilution chequerboard method was used to examine additive/antagonistic/synergistic effects between GLY/POE(15)/GBHs and imipenem by determining the fractional inhibitory concentration (FIC) indexes. Based on the FIC index values, glyphosate acid and Total demonstrated a potent antagonistic effect in all P. aeruginosa strains. Dominator Extra 608 SL and Fozat 480 reduced the activity of imipenem in only one strain (ATCC10145), while POE(15) and three other GBHs did not have any effect on susceptibility to imipenem. Considering the simultaneous presence of GBHs and imipenem in various environmental niches, the detected interactions between these chemicals may affect microbial communities. The mechanisms of the glyphosate and GBH-induced imipenem resistance in P. aeruginosa are yet to be investigated

Spatiotemporal analysis of multi-pesticide residues in the largest Central European shallow lake, Lake Balaton, and its sub-catchment area

Background The present study aimed to gain a comprehensive knowledge of the presence and environmental risks of pesticide and repellent residues in Lake Balaton and its sub-catchment area (Hungary). A unique analysis of 439 active substances and 17 metabolites was carried out on surface waters and one effluent wastewater as the only direct discharge into Lake Balaton from June 2017 until August 2020. Altogether 203 water- and 85 sediment samples were collected and analysed during the 3-year monitoring period. To determine the environmental risks of the detected pesticides to aquatic ecosystems, environmental risk assessment (ERA) was carried out using two approaches (worst- and general-case scenarios). Results Fifty-two pesticides and one insect repellent were detected, of which 26 belonged to herbicides (24 active substances and two metabolites), 15 to fungicides (15 active substances), and 11 to insecticides (eight active substances and three metabolites), of which only nine of the total analysed compounds are listed to be monitored in surface waters with threshold limit values (TLVs). The most frequently detected compounds were terbuthylazine, diethyltoluamide (DEET), desethyl-atrazine, and metolachlor. Glyphosate, aminomethylphosphonic acid (AMPA), and DEET were found with the highest concentrations of 3.0, 2.0, and 1.57 µg/L, respectively. The pesticide exposures were higher during the summer periods indicating a stable seasonal pattern. According to the performed ERA, the calculated Risk Quotients (RQs) indicated 18 compounds with a high level of risk including nine that had been banned for at least a decade. Discussion This study expands knowledge on the spatiotemporal occurrence of pesticides in inland surface waters and highlights the need to consider widening the number of analysed pesticides beyond the European Water Framework Directive (EWFD). According to our results, additional authority and legislation procedures should come into force for pesticides not indexed in the priority European Union Watch List

Presence, variation, and potential ecological impact of microplastics in the largest shallow lake of Central Europe

The presence of microplastics (MPs) in the global ecosystem has generated a rapidly growing concern worldwide. Although their presence in the marine environment has been well-studied, much less data are available on their abundance in freshwaters. MPs alone and in combination with different chemicals has been shown to cause acute and chronic effects on algae and aquatic invertebrate and vertebrate species at different biological levels. However, the combined ecotoxicological effects of MPs with different chemicals on aquatic organisms are still understudied in many species and the reported data are often controversial. In the present study, we investigated, for the first time, the presence of MPs in Lake Balaton, which is the largest shallow lake of Central Europe and an important summer holiday destination. Moreover, we exposed neonates of the well-established ecotoxicological model organism Daphnia magna to different MPs (polystyrene [3 μm] or polyethylene [≤ 100 μm]) alone and in combination with three progestogen compounds (progesterone, drospirenone, levonorgestrel) at an environmentally relevant concentration (10 ng L−1) for 21 days. The presence of 7 polymer types of MPs in the size range of 50–100 μm was detected in Lake Balaton. Similarly to the global trends, polypropylene and polyethylene MPs were the most common types of polymer. The calculated polymer-independent average particle number was 5.5 particles m−3 (size range: 50 μm – 100 μm) which represents the values detected in other European lakes. Our ecotoxicological experiments confirmed that MPs and progestogens can affect D. magna at the behavioral (body size and reproduction) and biochemical (detoxification-related enzyme activity) levels. The joint effects were negligible. The presence of MPs may lead to reduced fitness in the aquatic biota in freshwaters such as Lake Balaton, however, the potential threat of MPs as vectors for progestogens may be limited

Pathogenic and phylogenetic features of 2 multiresistant Pseudomonas aeruginosa strains originated from remediated sites

Objectives: To evaluate the possible occupational hazard of environmental strains of opportunistic Pseudomonas aeruginosa on hydrocarbon contaminated sites during remediation, 2 multidrugresistant isolates originating from environmental (soil and groundwater) samples were examined. Material and Methods: Antibiotic resistance profiles of the examined 2 strains were determined by Etest® against 20 different agents. Virulence investigations included the hemolytic activity test, the detection of virulence-related gene sequences such as exoA, exoU, exoS, exoY, exoT and the determination of intraperitoneal LD50 (the lethal dose, 50%) values in a mouse model. The hydrocarbon-degrading ability was evaluated in a gravimetric experiment, in vitro. The phylogenetic relationship of the isolates was investigated with a multilocus sequence typing scheme. Results: Multidrug resistant environmental strains of P. aeruginosa are strongly related to isolates that have proven effects on the infection of patients who suffer from cystic fibrosis, have a notable hemolytic activity, carry important virulence markers (exoS or exoU, respectively) and retain their hydrocarbon degradation ability (87.4% and 62.8% hydrocarbon degradation rate, respectively). Conclusions: Pseudomonas aeruginosa presumably raise considerable concerns for human health in the environment, already well known among nosocomial isolates, and the application of environmental strains of this species for environmental purposes is questionable

A mikrobiom kutatás szerepe az akvakultúrában

A mikrobiom kutatás az akvakultúra ágazat jelentős részét képező valódi csontos halak esetében hatalmas fejlődésen ment át az elmúlt évtizedekben. A tudományos érdeklődést indokolja, hogy a halak nem csupán a gerincesek törzsének legsokszínűbb képviselői, de megkérdőjelezhetetlen gazdasági jelentőséggel is bírnak. A csontos halak mikrobiomjának megértése a fenntartható akvakultúra vonatkozásában kiemelten fontos: kulcsszerepet játszhat az egészséges immunrendszer kialakításában, a zárt rendszerekben történő termelés és takarmányozás sikerességében. Ennek ellenére a mikroba közösségek összetételére és funkciójára vonatkozóan az ismeretek hiányosak. A jövőbeni kutatások célja a fajspecifikus mikroba közösségek, valamint az ágazat új, innovatív termelési folyamatai közötti összefüggések megismerése (rovarliszt alapú teljesértékű takarmányok, vakcinázás, pro- és prebiotikumok felhasználása, ivarsejt minőség, extenzív vagy intenzív termelés), melyek új beavatkozási lehetőségeknek nyithatnak utat