Background The present study aims the characterization of antibiotic resistance phenotypes and encoding genes in bacterial strains isolated from some Romanian aquatic fishery lowland salted lakes. Material/Methods This study was conducted on 44 bacterial strains, mainly belonging to species used as microbiological indicators of fecal pollution isolated from four natural fishery lakes. All strains were tested for their antibiotic susceptibility by disk diffusion method. Simplex and multiplex PCR were performed to identify the β-lactams antibiotic resistance genes (blaNMD, blaOXA−48, blaVIM, blaIMP, blaCTX−M, blaTEM), sulfonamides (Sul1, Sul2), tetracyclines (TetA, TetB, TetC, TetD, TetM), aminoglycosides (aac3Ia), vancomycin (VanA, VanB, VanC), macrolides (ermA, ermB, ermC) as well as the plasmid-mediated quinolone resistance (PMQR) markers (QnrA, QnrB, QnrS), and class 1 integrons (Int1, drfA1-aadA1). Results The Enterococcus spp. isolates exhibited phenotypic resistance to vancomycin (35 %) and macrolides (erythromycin) (75 %); from the vancomycin – resistant strains, 5 % harboured VanA (E. faecalis), while the erythromycin resistant isolates were positive for the ermA gene (E. faecalis − 10 %, E. faecium − 5 %). The Gram- negative rods (GNR) exhibited a high level of resistance to β-lactams: cefuroxime (63 %), cefazolin (42 %), ceftriaxone (8 %), ceftazidime and aztreonam (4 % each). The genetic determinants for beta-lactam resistance were represented by blaCTX−M−like (33 %), blaNDM−like and blaIMP−like (8.33 %) genes. The resistance to non-β-lactam antibiotics was ascertained to the following genes: quinolones (QnrS − 4.16 %); sulfonamides (Sul1–75 %, Sul2–4.16 %); aminoglycosides (aac3Ia − 4.16 %); tetracyclines (tetA – 25 %, tetC − 15 %). The integrase gene was found in more than 50 % of the studied strains (58.33 %). Conclusions The cultivable aquatic microbiota from fishery lakes is dominated by enterococci and Enterobacterales strains. The GNR strains exhibited high levels of β-lactam resistance mediated by extended spectrum beta-lactamases and metallo-β-lactamases. The Enterococcus sp. isolates were highly resistant to macrolides and vancomycin. The high level and diversity of resistance markers, correlated with a high frequency of integrons is suggesting that this environment could act as an important reservoir of antibiotic resistance genes with a great probability to be horizontally transmitted to other associated species from the aquatic sediments microbiota, raising the potential zoonotic risk for fish consumers.

Abstract-The main objective of this paper is the assessment of surface water quality polluted with various heavy metals (HM) using the quality indices and the information submitted may be useful for the competent authorities and the public. Cadmium

Pseudomonas aeruginosa is a non-fermentative Gram-negative opportunistic pathogen, frequently encountered in difficult-to-treat hospital-acquired infections and also wastewaters. The natural resistance of this pathogen, together with the frequent occurrence of multidrug-resistant strains, make current antibiotic therapy inefficient in treating P. aeruginosa infections. Antibiotic therapy creates a huge pressure to select resistant strains in clinical settings but also in the environment, since high amounts of antibiotics are released in waters and soil. Essential oils (EOs) and plant-derived compounds are efficient, ecologic, and sustainable alternatives in the management of various diseases, including infections. In this study, we evaluated the antibacterial effects of four commercial essential oils, namely, tea tree, thyme, sage, and eucalyptus, on 36 P. aeruginosa strains isolated from hospital infections and wastewaters. Bacterial strains were characterized in terms of virulence and antimicrobial resistance. The results show that most strains expressed soluble pore toxin virulence factors such as lecithinase (89–100%) and lipase (72–86%). All P. aeruginosa strains were positive for alginate encoding gene and 94.44% for protease IV; most of the strains were exotoxin producers (i.e., 80.56% for the ExoS gene, 77.78% for the ExoT gene, while the ExoU gene was present in 38.98% of the strains). Phospholipase-encoding genes (plc) were identified in 91.67/86.11% of the cases (plcH/plcN genes). A high antibiotic resistance level was identified, most of the strains being resistant to cabapenems and cephalosporins. Cabapenem resistance was higher in hospital and hospital wastewater strains (55.56–100%) as compared to those in urban wastewater. The most frequently encountered encoding genes were for extended spectrum β-lactamases (ESBLs), namely, blaCTX-M (83.33% of the strains), blaSHV (80.56%), blaGES (52.78%), and blaVEB (13.89%), followed by carbapenemase-encoding genes (blaVIM, 8.33%). Statistical comparison of the EOs’ antimicrobial results showed that thyme gave the lowest minimum inhibitory concentrations (MIC) and minimum biofilm eradication concentrations (MBEC) in P. aeruginosa-resistant isolates, making this EO a competitive candidate for the development of efficient and ecologic antimicrobial alternatives.

One of the main concerns of the developing world is the mitigation of pollution of environmental components together with the recovery and reuse of valuable substances from waste resulting during diverse anthropic activities. Wastewater generated by agro-zootechnic activities is a source of nutrients (nitrogen and phosphorus compounds) and traditionally it is reused for crops irrigation. However adverse effects on the environment may be caused should a proper treatment not be performed, considering the spread of additives/drugs altering the natural metabolism in modern livestock industries and subsequently their presence in waste. In this context, research was conducted on laboratory scale setups of some advanced treatment processes for wastewater resulting from cattle farms. UV disinfection and oxidation using ozone were investigated in order to emphasize the antimicrobial effect and their contribution to the improvement of water quality. The permissible irrigation water quality which varied based on the crop type was the decisive factor in adjusting the experimental setup and effluent quality. The results have revealed the inactivation of bacteriological indicators up to 99% and even 100% in the case of faecal coliforms and faecal streptococci. Moreover, ozonation allows also the removal of organic matter, with an efficiency of over 80%. This research offers solutions suitable for areas where the water demand exceeds availability and in the regions affected by drought.