Prevalence of Arcobacter and Other Pathogenic Bacteria in River Water in Nepal

Abstract

This study aims to determine the diversity of pathogenic bacteria in the Bagmati River, Nepal, during a one-year period. A total of 18 river water samples were collected from three sites (n = 6 per site) along the river. Bacterial DNA, which were extracted from the water samples, were analyzed for bacterial 16S rRNA genes by next-generation sequencing for 13 of 18 samples, and by quantitative PCR targeting Arcobacter for all 18 samples. The 16S rRNA sequencing identified an average of 97,412 ± 35,909 sequences/sample, which were then categorized into 28 phyla, 61 classes, and 709 bacterial genera. Eighteen (16%) genera of 111 potential pathogenic bacteria were detected with abundance ratios of >1%; Arcobacter, Acinetobacter, and Prevotella were the dominant genera. The Arcobacter abundance ratios were 28.6% (n = 1), 31.3 ± 15.8% (n = 6), and 31.8 ± 17.2% (n = 6) at the upstream, midstream, and downstream sites, respectively. Arcobacter was detected in 14 (78%) of 18 samples tested, with concentrations ranging from 6.7 to 10.7 log10 copies/100 mL, based on quantitative PCR. Our results demonstrate the poor bacterial quality of the Bagmati River water, suggesting a need for implementing more measures to reduce fecal contamination in the river water.

The Occurrence of Antibiotic Resistance Genes in an Urban River in Nepal

“…As reported previously [11,12], 100-mL river water samples were collected in sterile bottles once every 2 months between November 2015 and September 2016 from Sundarijal (upstream), Thapathali (midstream), and Chovar (downstream), as shown in Figure 1. Land cover usage details on the map were based on a previously conducted study [14].…”

“…It flows from north to south in the Kathmandu Valley, passing through the densely populated region. Previous studies have reported a degraded microbiological quality of water and showed that the Bagmati River is a reservoir of pathogenic bacteria, viruses, and protozoa [10][11][12]. However, studies regarding the detection of clinically relevant ARGs and MGEs have not been published.…”

From the Andes to the desert: First overview of the bacterial community in the Rimac river, the main source of water for Lima, Peru

“…In addition, they also found Arcobacter cryaerophilus, as the predominant species in the river. This species has been reported as very frequent in other rivers such as the Yangtze (China) [37], many rivers in Nepal [38], and the Llobregat (Spain) [39]. As mentioned before, Arcobacter is an emergent enteropathogen and indicator of fecal contamination.…”

From the Andes to the desert: 16S rRNA metabarcoding characterization of aquatic bacterial communities in the Rimac river, the main source of water for Lima, Peru

“…Arcobacter cryaerophilus, the predominant species in the Lower Rimac, has been reported as very frequent in other rivers such as the Yangtze (China) [49], many rivers in Nepal [52], the Llobregat (Spain) [53], and the Pinheiros river [14]. As mentioned before, Arcobacter is an emergent enteropathogenic bacterium and an indicator of fecal contamination.…”