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Acinetobacter species are common inhabitants of freshwater and marine ecosystems with a capacity to induce disease in affected fish. To facilitate their rapid and reliable identification, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), was applied to Acinetobacter from fish. The aims of the study were, thus, to identify and profile the Acinetobacter species from tissues of fish living in a vulnerable environment impacted by wastewaters, and to assess the potential of MALDI-TOF MS as a method for discriminating these acinetobacters. Fish were sampled from waterways impacted by the activity of a wastewater treatment plant. Samples of gills, spleen, kidney and liver were streaked onto general-purpose media to purity. The profiling and identification of acinetobacters was conducted with MALDI-TOF MS, with the samples prepared by ethanol/formic acid extraction.The identified acinetobacters were retrieved from gills (68.96 %), kidney (13.79 %), liver (10.34 %), and spleen (6.89 %). The Acinetobacter species isolated from all tested fish tissues were A. johnsonii (79.31 %), A. pittii (10.34 %), A. tandoii (3.44 %), A. guilouiae (3.44 %), and A. gerneri (3.44 %). Highly probable and probable species identifications were obtained for 48.27 % of all acinetobacters tested, indicating fully reliable identification. MALDI‐TOF MS gave excellent identification and profiling results for piscine Acinetobacter species from the wastewater-affected waterways. It is a recommendable technique for future Acinetobacter species discrimination, as accurate and rapid identification of these bacteria is critical in both environmental pollution management and human/veterinary clinical diagnostics.

Wastewaters from a treatment plant discharging into a canal harboring fish may present sources of microbiological hazard for wild fish. Such fish, inhabiting microbiologically polluted bodies of water, can be contaminated by human pathogens and, if used for human consumption, may pose a risk to public health. Hence, in this work the aim was to identify tested strains from tissues of wild fish living in the receiving water bodies, captured from locations up to 12 km from the point of discharge of treated water of town Virovitica in order to assess the bacterial threat of the WWTP on fish and potentially on public health. A rather rich diversity of bacterial genera was isolated from gill tissues and internal organs. The most frequent isolate was Aeromonas hydrophila which has gained public health recognition as an opportunistic pathogen. Vibrio cholerae, an indicator bacterium for aquatic contamination, was retrieved from all investigated tissues. Opportunistic human pathogens as well as some zoonotic agents were also retrieved from fish tissues (Enterobacter amnigenus, Acinetobacter spp., Ochrobactrum anthropi, Pseudomonas aeruginosa, Flavimonas (Pseudomonas) oryzihabitans, Shewanella putrefaciens and others). Public health hazard is particularly pronounced regarding local recreational fishermen who fish out, handle and consume fish from respective waters.

Wastewaters from a treatment plant discharging into a canal harboring fish may present sources of microbiological hazard for wild fish. Such fish, inhabiting microbiologically polluted bodies of water, can be contaminated by human pathogens and, if used for human consumption, may pose a risk to public health. Hence, in this work the aim was to identify tested strains from tissues of wild fish living in the receiving water bodies, captured from locations up to 12 km from the point of discharge of treated water of town Virovitica in order to assess the bacterial threat of the WWTP on fish and potentially on public health. A rather rich diversity of bacterial genera was isolated from gill tissues and internal organs. The most frequent isolate was Aeromonas hydrophila which has gained public health recognition as an opportunistic pathogen. Vibrio cholerae, an indicator bacterium for aquatic contamination, was retrieved from all investigated tissues. Opportunistic human pathogens as well as some zoonotic agents were also retrieved from fish tissues (Enterobacter amnigenus, Acinetobacter spp., Ochrobactrum anthropi, Pseudomonas aeruginosa, Flavimonas (Pseudomonas) oryzihabitans, Shewanella putrefaciens and others). Public health hazard is particularly pronounced regarding local recreational fishermen who fish out, handle and consume fish from respective waters. [ABSTRACT FROM AUTHOR]

Identification of bacteria in aquatic and environmental applications, for monitoring purposes and research, for health assessments and therapy considerations of farmed and free-living aquatic organisms, still relies on conventional phenotypic and biochemical protocols. Although molecular techniques based on DNA amplification and sequencing are finding ways into diagnostic laboratories, they are time-consuming, costly and difficult in the case of multiplex assays. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) is a rapid and accurate proteomic method reliable for identification of unknown bacteria to the genus and species level. Upon extension of databases, it will certainly find its position in environmental sciences. The paper presents an overview of the principle of the method, its effectiveness in comparison with conventional and molecular identification procedures, and applicability on environmental and aquatic isolates, discussing its advantages and shortcomings, as well as possible future implementations. [ABSTRACT FROM AUTHOR]

Relating the treated wastewater quality and its impact on organismic biosensors (Prussian carp, Carassius gibelio and earthworm, Eisenia fetida ) was the main objective of the study. The impact on health status of fish living downstream, microbiological contamination and antimicrobial resistance, fish tissue structure, blood biochemistry, oxidative stress, genotoxic effects, as well as multixenobiotic resistance mechanism (MXR) was assessed. Treated wastewater discharged from the WWTP modified the environmental parameters and xenobiotic concentrations of the receiving surface waters. Potential bacterial pathogens from fish and respective waters were found in relatively low numbers, although they comprised aeromonads with a zoonotic potential. High resistance profiles were determined towards the tested antimicrobial compounds, mostly sulfamethoxazole and erythromycin. Histopathology primarily revealed gill lamellar fusion and reduction of interlamellar spaces of effluent fish. A significant increase in plasma values of urea, total proteins, albumins and triglycerides and a significant decrease in the activity of plasma superoxide dismutase were noted in carp from the effluent-receiving canal. Micronucleus test did not reveal significant differences between the examined groups, but a higher frequency of erythrocyte nuclear abnormalities was found in fish sampled from the effluent-receiving canal. Earthworms indicated to the presence of MXR inhibitors in water and sludge samples, thus proving as a sensitive sentinel organism for environmental pollutants. The integrative approach of this study could serve as a guiding principle in conducting evaluations of the aquatic habitat health in complex bio-monitoring studies. [ABSTRACT FROM AUTHOR]