Seasonal Shift in Physicochemical Factors Revealed the Ecological Variables that Modulate the Density of Acinetobacter Species in Freshwater Resources

Abstract

Certain environmental variables are responsible for the survival of microorganisms in aquatic environments. The influence of these environmental factors in each season (winter, autumn, spring and summer) of the year can be used to track changes in a microbial population in freshwater resources. In this study, we assessed the effect of seasonal shifts in environmental variables including temperature, pH, total dissolved solids (TDS), total suspended solids (TSS), biochemical oxygen demand (BOD) and turbidity (TBS) among others on the density of Acinetobacter species in the Great Fish, Keiskamma and Tyhume rivers in the Eastern Cape Province, South Africa. Water samples and values of the environmental factors were taken from the rivers for 12 months. The density of presumptive Acinetobacter species was estimated from the culture of water samples on a CHROMagar selective medium, while the Acinetobacter-specific recA gene was targeted for the identification of Acinetobacter species using PCR assay. The multivariate relationship between seasons and changes in variables was created using PCA, while the effect of seasonal shifts in the environmental variables on the density of Acinetobacter species was evaluated using correlation test and topological graphs. Positive association patterns were observed between the seasons, environmental factors and the bacterial density in the rivers. In addition, temperature, TBS, TSS and BOD tended to influence the bacterial density more than other physicochemical factors in the rivers across the seasons. Of the total 1107 presumptive Acinetobacter species, 844 were confirmed as Acinetobacter species. Therefore, these findings suggested that the rivers contain Acinetobacter species that could be useful for basic and applied study in ecology or biotechnology, while their clinical relevance in causing diseases cannot be underestimated.

Effects of Lysophospholipid Supplementation in Feed with Low Protein or Lipid on Growth Performance, Lipid Metabolism, and Intestinal Flora of Largemouth Bass (Micropterus salmoides)

“…Interestingly, this is corroborated by the higher protein content of fish body in group LP-Ly. In addition, Acinetobacter has been associated with disease infections in tilapia and humans [ 60 , 61 ], and the results of the present study showed that its abundance was significantly higher in the LL-Ly group, which may increase the risk of disease infection in fish.…”

MALDI-TOF MS profiling of piscine Acinetobacter species from wastewater-related waters

“…The probable genus was identified for 41.38 %, and unreliable identification was signified for 3.44 % of isolates. For 89.66 % of acinetobacters examined, the second-best matches were also acinetobacters (Adewoyin and Okoh, 2020;Doughari et al, 2011).…”

“…The public health risk is, thus, a significant concern when handling fish from wastewater-related waters. Reassuringly, selected strains of Acinetobacter species have shown ecological and economic importance in bioremediation of industrial effluents (Adewoyin and Okoh, 2020). However, MALDI-TOF MS reference databases, although fairly adequate for the majority of routine medical and veterinary clinical bacteria isolates (Topić Popović et al, 2021), need continuous updating for environmental species such as Acinetobacter.…”

“…One of the characteristics of Acinetobacter species is their ability to survive in adverse environmental conditions. They have previously been isolated from raw sewage, wastewater treatment plants, and activated sludge (Adewoyin and Okoh, 2020;Topić Popović et al, 2015a;Doughari et al, 2011). The aims of this study were, thus, to identify and profile the Acinetobacter species from tissues of fish living in a highly vulnerable environment impacted by wastewaters and to assess the potential of the MALDI-TOF MS method used to discriminate these bacteria.…”

Abundance and antimicrobial susceptibility of Shigella spp. isolated from aquatic environments in Banda Aceh, Indonesia

“…The pH of the river water was generally neutral to slightly alkaline in each of the samples taken from the different rivers (6.5-8.0). Washing dishes and laundry in strongly alkaline water, as well as the customary ritual washing along the river channel, can also lead to an increase in pH (Adewoyin and Okoh 2020). Additionally, exposure to wastewater effluent from agricultural and animal rearing may increase the pH since agricultural activities involving application of alkaline fertilizers may cause the water body's pH to rise due to runoff from farms.…”