Evaluation of bottled drinking water and occurrence of multidrug-resistance and biofilm producing bacteria in Nepal.

Health consequences arising from unsafe drinking water and water insecurity lead to increased reliance on usage of bottled water. Biofilm-producing antibiotic-resistant bacteria in bottled water may pose a risk to public health. This study aims to assess the quality of bottled drinking water with a focus on biofilm-producing and drug-resistant coliform. We analyzed 60 bottled water samples of 30 different brands purchased from Kathmandu for physicochemical and microbial analysis. The parameters pH, iron, total coliform count, Escherichia coli count, and fecal coliform count exceeded National Drinking Water Quality Standards, 2022 in 30.00%, 16.67%, 66.67%, 23.33%, and 16.67% of samples, respectively. Water quality index measurement showed 36.67% and 6.67% of bottled water samples were categorized as grade A and grade B indicating excellent and good water quality, respectively. However, 56.67% of bottled water samples fall under grade E meaning unsuitable for drinking. Among 14 coliform isolates, 85.71% and 14.29% were identified as E. coli and Klebsiella spp, respectively. The antibiotic susceptibility testing revealed that 28.57% of the isolates were multidrug-resistant and Gentamicin resistant isolates comprised 71.43%. However, none of the isolates were carbapenem (meropenem) resistant. In this study, 42.87% of the isolates were found biofilm producers with 14.29% each of strong, moderate, and weak biofilm producers. The genetic potential of biofilm-producing capacity of the isolates was assessed by Polymerase Chain Reaction amplification of bcsA and csgD genes. Our results showed that 66.67% and 50.00% of the isolates harbored bcsA and csgD genes, respectively. This study highlights potential public health hazards associated with the consumption of bottled water containing biofilm-producing and drug-resistant bacteria in Nepal.

High efficient removal of 4-aminophenylarsonic acid from aqueous solution via enhanced FeOOH using Mn(VII).

Efficient removal of 4-aminophenylarsonic acid from contaminated water sources is essential to mitigate arsenic pollution. We proposed a competent technique to achieve 4-aminophenylarsonic acid removal via adsorption on enhanced α-FeOOH using various concentrations of Mn(VII). The elimination rate of 4-aminophenylarsonic acid applying FeOOH with Mn(VII) was dependent on acidic conditions. More than 99.9% of 4-aminophenylarsonic acid was eliminated in a 6-min reaction time under acidic conditions. The reaction of 4-aminophenylarsonic acid was fast at 4.0 and 5.0 pH, with its complete oxidation into arsenate and the liberation of manganese Mn(II) in the initial stage of the reaction. Similarly, the reaction rate constant (kobs) decreased from 0.7048 ± 0.02 to 0.00155 ± 0.00007 as the pH increased from 4.0 to 9.0. Oxidation capacity was considerably enhanced via the removal of electrons from 4-aminophenylarsonic acid to Mn(VII) after the creation of its radical intermediate and further change in Mn(III) to Mn(II) in the solution. The results showed that Mn(VII) played a crucial role in 4-aminophenylarsonic acid degradation at a low pH (e.g., 4.0), and the oxidation process proceeded in different manners, namely, electron transfer, hydroxylation, and ring-opening. These results illustrated that Mn(VII) is an effective, economic purification process to mitigate 4-aminophenylarsonic acid generated from poultry waste.

Antibiotic Resistance, Biofilm Formation and Sub-Inhibitory Hydrogen Peroxide Stimulation in Uropathogenic Escherichia coli.

Uropathogenic Escherichia coli (UPEC) is the most prevalent cause of urinary tract infections (UTIs). Biofilm formation and antibiotic resistance could be high among the causative agent. The purpose of this study was to determine antibiotic resistance, biofilm production, and biofilm-associated genes, bcsA and csgD, and sub-inhibitory hydrogen peroxide (H2O2) stimulation in UPEC for biofilm formation. A total of 71 UPEC were collected from a tertiary care hospital in Kathmandu and subjected to identify antibiotic susceptibility using Kirby-Bauer disk diffusion. The biofilm formation was assessed using microtiter culture plate method while pellicle formation was tested by a tube method. In representative 15 isolates based on biofilm-forming ability, bcsA and csgD were screened by conventional polymerase chain reaction, and treated with sub-lethal H2O2. The UPEC were found the most susceptible to meropenem (90.2%), and the least to ampicillin (11.3%) in vitro and 90.1% of them were multi-drug resistant (MDR). Most UPEC harbored biofilm-producing ability (97.2%), and could form pellicle at 37°C. Among representative 15 isolates, csgD was detected only among 10 isolates (66.67%) while bcsA gene was present in 13 isolates (86.67%). This study revealed that level of biofilm production elevated after sub-lethal H2O2 treatment (P = .041). These findings suggested that the pathogens are emerging as MDR. The biofilm production is high and the majority of selected strains contained bcsA and csgD genes. Pellicle formation test was suggestive to be an alternative qualitative method to screen biofilm production in UPEC. The sub-inhibitory concentration of H2O2 may contribute in increasing biofilm formation in UPEC.