Browsing by Author "Gazdag, Z."

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Occurrence of Antibiotics and Bacterial Resistance Genes In Wastewater: Resistance Mechanisms and Antimicrobial Resistance Control Approaches
(World Journal of Microbiology and Biotechnology, 2022) Mutuku, C.; Gazdag, Z.; Melegh, S.
Antimicrobial pharmaceuticals are classified as emergent micropollutants of concern, implying that even at low concentra- tions, long-term exposure to the environment can have significant eco-toxicological effects. There is a lack of a standardized regulatory framework governing the permissible antibiotic content for monitoring environmental water quality standards. Therefore, indiscriminate discharge of antimicrobials at potentially active concentrations into urban wastewater treatment facilities is rampant. Antimicrobials may exert selective pressure on bacteria, leading to resistance development and eventual health consequences. The emergence of clinically important multiple antibiotic-resistant bacteria in untreated hospital efflu- ents and wastewater treatment plants (WWTPs) has been linked to the continuous exposure of bacteria to antimicrobials. The levels of environmental exposure to antibiotics and their correlation to the evolution and spread of resistant bacteria need to be elucidated to help in the formulation of mitigation measures. This review explores frequently detected antimicrobials in wastewater and gives a comprehensive coverage of bacterial resistance mechanisms to different antibiotic classes through the expression of a wide variety of antibiotic resistance genes either inherent and/or exchanged among bacteria or acquired from the reservoir of antibiotic resistance genes (ARGs) in wastewater systems. To complement the removal of antibiotics and ARGs from WWTPs, upscaling the implementation of prospective interventions such as vaccines, phage therapy, and natural compounds as alternatives to widespread antibiotic use provides a multifaceted approach to minimize the spread of antimicrobial resistance.
Plasmid Sequence Dataset of Multidrug-Resistant Enterobacterales Isolated from Hospital Effiuents and Wastewater Treatment Plant
(Elsevier Inc., 2022) Mutuku, C.; Kutasy, B.; Urban, P.; Melegh, S.; Herczeg, R.; Gazdag, Z.; Virág, E.
We present plasmid sequences of 21 multidrug resistant iso- lates of Enterobacterales belonging to Escherichia coli (n=10), Klebsiella pneumoniae (n=9), Klebsiella oxytoca (n=1), and Cit- robacter freundii (n=1). The isolates originated from effiuent collected from hospital sewer pipes and from a wastewa- ter treatment plant (WWTP) in a southwestern Hungarian city. Isolation was carried out using eosin methylene blue agar supplemented with ceftriaxone and the isolates were identified with MALDI-TOF MS. Screening for multidrug re- sistance was conducted by determining susceptibility to four chemical classes namely, beta-lactams, aminoglycoside, flu- oroquinolone, and sulfonamide. Plasmid DNA was isolated by the alkaline lysis method using the Monarch plasmid DNA miniprep kit from freshly grown pure colonies. Molecular typing and Illumina sequencing of plasmid DNA of mul- tiresistant strains were performed. After the assembly of contigs, genes localized on plasmid sequences were deter- mined and functionally annotated. These reconstructed plas- mid sequences supplemented with gene functional anno- tations were deposited in the Mendeley data. Using these datasets different plasmid incompatibility groups were iden- tified. These conjugative plasmids appear to play a key role in the transmission of multiple resistance genes in enteric bac- teria via wastewater. The presented data may provide useful insight on the correlations between environmental antibiotic contamination and the development of bacterial resistance, which poses a serious public health threat.