The Occurrence of Potentially Pathogenic and Antibiotic Resistant Gram-Negative Bacteria Isolated from the Danube Delta Ecosystem

Abstract

The spread of a growing number of antibiotic-resistant bacteria (ARB) outside the clinical setting into the environment has been observed. The surface water plays an important role in ARB dissemination by being both habitats and transport systems for microorganisms. The ecological and touristic importance of the Danube Delta make it a European priority for close monitoring of its freshwater system. The main goal of this paper was to analyze how the St. Gheorghe branch of the Danube Delta microbiological contamination and their antibiotic-resistant profile were influenced by climate change, especially the global warming from 2013 up to 2019. In the surface water from all sampling points, total and fecal coliform bacteria showed a constant colony forming units (CFU) increase tendency during the years, with a sharp rise from 1500 CFU/mL in 2015 to more than 20,000 CFU/mL in 2019. The bacterial population’s analyses revealed an indirect proportionality between coliform bacteria density in water and sediment during the years in accordance with global warming. The most commonly identified bacterial strains such as Escherichia coli, Klebsiella oxytoca, Citrobacter freundii and Proteus mirabilis have been shown a resistance rate of approximatively 70% to beta-lactam antibiotics, especially to ampicillin and amoxicillin-clavulanate.

Antimicrobial Resistance in Romania: Updates on Gram-Negative ESCAPE Pathogens in the Clinical, Veterinary, and Aquatic Sectors

“…This basin represents an optimal pool for resistant pathogens and anthropogenic pollutants dissemination and accumulation throughout large and distant areas, being assigned as a reservoir of AR. Previously, it has been demonstrated that Bucharest was at the top of the most polluted sampling locations from twelve WWTPs in nine countries (Romania, Serbia, Hungary, Slovenia, Croatia, Slovakia, Czechia, Austria, and Germany) in the Danube River Basin collected and analyzed for ARGs and MGE presence [395].…”

Seasonal influences on microbiological quality of aquatic ecosystems

“…Extensive studies have been carried out to match bacterial community structure and function with different aquatic systems types. There are systems that change their physical and ecological proprieties depending on the spatio-temporal and environmental conditions [1]. Over the time, the aquatic systems have been under the pressure of natural changes and, recently, they have been more and more under anthropic pollution pressure due to a rapid development of economy and population growth [2].…”

Coordination Compounds of Platinum and Palladium with Mixed Ligands (Usnic Acid and 1-(o-Tolyl) Biguanide) � Synthesis, Spectral Characterization and Biological Activity

“…Most bacteria are very resistant and adaptive microorganisms to environmental changes mainly due to their defense mechanism based on the efflux pumps which eliminate the toxic compounds from inside cells. Bacteria could have different defense response based on the presence of harmful compounds in the environment [38,39]. Various bacterial strains (Pseudomonas aeruginosa, Staphylococcus warneri and Pseudomonas aurantica) proved to be very effective in Reldan EC40 pesticide (Nita-Lazar et al [40]) and pharmaceutical compounds metabolisation (Nita-Lazar et al [41]).…”