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

Long-term longitudinal monitoring of SARS CoV-2 in urban rivers and sewers of Nepal

In regions without adequate centralized wastewater treatment plants, sample collection from rivers and sewers can be an alternative sampling strategy for wastewater surveillance. This study aimed to assess the feasibility of alternative sampling strategies by testing samples collected from rivers (n = 246) and sewers (n = 244) in the Kathmandu Valley between March 2021 and February 2022. All samples were concentrated using the skimmed-milk flocculation method and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA was quantified using the nucleocapsid (N) and envelope (E) genes qPCR assays. Of the total, 75 % (371/490) of the samples tested positive using at least one qPCR assay, with concentrations ranging from 3.0 to 8.3 log10 gene copies/L. No significant correlation between concentrations of SARS-CoV-2 from both sewers and river with the number of confirmed coronavirus disease 2019 (COVID-19) cases in the Kathmandu valley was observed (p > 0.05). Despite the high concentration of SARS-CoV-2 in rivers and sewers, we hypothesize this finding to be a result of inaccurate number of clinical cases possibly due to inadequate clinical testing. This longitudinal study further supports the statement to consider sampling strategies from sewers and rivers for WBS in Nepal and other low and middle-income countries.

A Review on the Prevalence of Arcobacter in Aquatic Environments

Arcobacter is an emerging pathogen that is associated with human and animal diseases. Since its first introduction in 1991, 33 Arcobacter species have been identified. Studies have reported that with the presence of Arcobacter in environmental water bodies, animals, and humans, a possibility of its transmission via water and food makes it a potential waterborne and foodborne pathogen. Therefore, this review article focuses on the general characteristics of Arcobacter, including its pathogenicity, antimicrobial resistance, methods of detection by cultivation and molecular techniques, and its presence in water, fecal samples, and animal products worldwide. These detection methods include conventional culture methods, and rapid and accurate Arcobacter identification at the species level, using quantitative polymerase chain reaction (qPCR) and multiplex PCR. Arcobacter has been identified worldwide from feces of various hosts, such as humans, cattle, pigs, sheep, horses, dogs, poultry, and swine, and also from meat, dairy products, carcasses, buccal cavity, and cloacal swabs. Furthermore, Arcobacter has been detected in groundwater, river water, wastewater (influent and effluent), canals, treated drinking water, spring water, and seawater. Hence, we propose that understanding the prevalence of Arcobacter in environmental water and fecal-source samples and its infection of humans and animals will contribute to a better strategy to control and prevent the survival and growth of the bacteria.

The Prevalence of Arcobacteraceae in Aquatic Environments: A Systematic Review and Meta-Analysis

Members of the family Arcobacteraceae are distributed widely in aquatic environments, and some of its species have been associated with human and animal illness. However, information about the diversity and distribution of Arcobacteraceae in different water bodies is still limited. In order to better characterize the health risk posed by members in the family Arcobacteraceae, a systematic review and meta-analysis-based method was used to investigate the prevalence of Arcobacteraceae species in aquatic environments based on available data published worldwide. The database search was performed using related keywords and considering studies up to February 2021. The pooled prevalence in aquatic environments was 69.2%, ranging from 0.6 to 99.9%. These bacteria have a wide geographical distribution, being found in diverse aquatic environments with the highest prevalence found in raw sewage and wastewater treatment plants (WWTP), followed by seawater, surface water, ground water, processing water from food processing plants and water for human consumption. Assessing the effectiveness of treatments in WWTP in eliminating this contamination, it was found that the wastewater treatment may not be efficient in the removal of Arcobacteraceae. Among the analyzed Arcobacteraceae species, Al. butzleri was the most frequently found species. These results highlight the high prevalence and distribution of Arcobacteraceae in different aquatic environments, suggesting a risk to human health. Further, it exposes the importance of identifying and managing the sources of contamination and taking preventive actions to reduce the burden of members of the Arcobacteraceae family.

Overgrowth control of potentially hazardous bacteria during storage of ozone treated wastewater through natural competition

Improving the chemical and biological quality of treated wastewater is particularly important in world regions under water stress. In these regions, reutilization of wastewater is seen as an alternative to reduce water demand, particularly for agriculture irrigation. In a reuse scenario, the treated wastewater must have enough quality to avoid chemical and biological contamination of the receiving environment. Ozonation is among the technologies available to efficiently remove organic micropollutants and disinfect secondary effluents, being implemented in full-scale urban wastewater treatment plants worldwide. However, previous studies demonstrated that storage of ozone treated wastewater promoted the overgrowth of potentially harmful bacteria, putting at risk its reutilization, given for instance the possibility of contaminating the food-chain. Therefore, this study was designed to assess the potential beneficial role of inoculation of ozone treated wastewater with a diverse bacterial community during storage, for the control of the overgrowth of potentially hazardous bacteria, through bacterial competition. To achieve this goal, ozone treated wastewater (TWW) was diluted with river water (RW) in the same proportion, and the resulting bacterial community (RW+TWW) was compared to that of undiluted TWW over 7 days storage. As hypothesized, in contrast to TWW, where dominance of Beta- and Gammaproteobacteria, namely Pseudomonas spp. and Acinetobacter spp., was observed upon storage for 7 days, the bacterial communities of the diluted samples (RW+TWW) were diverse, resembling those of RW. Moreover, given the high abundance of antibiotic resistance genes in RW, the concentration of these genes in RW+TWW did not differ from that of the non-ozonated controls (WW, RW and RW+WW) over the storage period. These results highlight the necessity of finding a suitable pristine diverse bacterial community to be used in the future to compete with bacteria surviving ozonation, to prevent reactivation of undesirable bacteria during storage of treated wastewater.

Release of Antibiotic-Resistance Genes from Hospitals and a Wastewater Treatment Plant in the Kathmandu Valley, Nepal

Hospitals and wastewater treatment plants (WWTPs) are high-risk point sources of antibiotic-resistance genes (ARGs) and antibiotic-resistant bacteria. This study investigates the occurrence of clinically relevant ARGs (sul1, tet(B), blaCTX-M, blaNDM-1, qnrS) and a class one integron (intI1) gene in urban rivers, hospitals, and municipal wastewater in the Kathmandu Valley, Nepal. Twenty-five water samples were collected from three rivers, six hospitals, and a wastewater treatment plant to determine the concentrations of ARGs and intI1 using quantitative polymerase chain reactions. From the results, all tested ARGs were detected in the river water; also, concentrations of ARGs in WWTP and hospital effluents varied from 6.2 to 12.5 log10 copies/L, highlighting the role of a WWTP and hospitals in the dissemination of ARGs. Except for blaNDM-1, significant positive correlations were found between intI1 and other individual ARGs (r = 0.71–0.96, p < 0.05), indicating the probable implications of intI1 in the transfer of ARGs. Furthermore, this study supports the statement that the blaNDM-1 gene is most likely to be spread in the environment through untreated hospital wastewater. Due to the interaction of surface water and groundwater, future research should focus on ARGs and factors associated with the increase/decrease in their concentration levels in drinking water sources of the Kathmandu Valley.

Prevalence, resistance to antimicrobials, and antibiotypes of Arcobacter species recovered from retail meat in Wasit marketplaces in Iraq

Background and Aim: Arcobacter is a food-borne pathogen associated with human and animal infections. In Iraq, these infections and their adverse effects on public health have not been well investigated. For this reason, as well as to submit data on the resistance to antimicrobials and antibiotypes of the Arcobacter spp. and their occurrence in retail meat in the Wasit marketplaces, this study was undertaken. Materials and Methods: A total of 83 samples of fresh raw (n=35) and chilled meat (n=48) were purchased randomly from marketplaces in various regions of the Wasit Governorate. Bacterial detection was conducted using cultural methods, biochemical analysis, and the Oxoid Biomedical Identification System Campy. Confirmation of these bacteria at the species level was performed using the multiplex polymerase chain reaction method. Susceptibility of the Arcobacter spp. to antimicrobials was investigated in 11 isolates comprising Arcobacter butzleri (n=9) and Arcobacter cryaerophilus (n=2) using the Kirby–Bauer disk diffusion method. Results: A total of 32 (38.6%) of the 83 fresh raw and chilled meat samples tested positive for Arcobacter spp.; of those, 27 (84.4%) and 5 (15.6%) were recognized as A. butzleri and A. cryaerophilus, respectively. Maximum resistance was perceived, respectively, to tetracycline, erythromycin, and ampicillin (90.9%, 81.8%, and 81.8%, respectively). In contrast, a low resistance rate against fluoroquinolones up to 9.09% was found. Antibiograms of the A. butzleri and A. cryaerophilus isolates yielded ten antibiotypes. The vast majority of the isolates (90.91%) were resistant to no fewer than three classes of antimicrobials, and 27.3% of these showed resistance to six antibiotics. A total of 91% of the analyzed isolates had a multiple antibiotic resistance index score between 0.27 and 0.73. Conclusion: Our outcomes demonstrated that retail meat can be a prospective vehicle for pathogenic Arcobacter, making these products a possible risk to human health. Our outcomes postulate that the contamination of retail meats by pathogenic Arcobacter is a global public health concern, particularly with the growing resistance to life-saving drugs, and emphasizes consumer understanding about the quality and safety of these products. To achieve healthy food products, good management practices, and successful control approaches must be implemented across the entire food chain, not only to protect consumers from these contaminants but also to minimize the risk of drug resistance.

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

The Rimac river is the main source of water for Lima, Peru's capital megacity. The river is constantly affected by different types of contamination including mine tailings in the Andes and urban sewage in the metropolitan area. In this work, we aim to produce the first characterization of aquatic bacterial communities in the Rimac river using a 16S rRNA metabarcoding approach which would be useful to identify bacterial diversity and potential understudied pathogens. We report a lower diversity in bacterial communities from the Lower Rimac (Metropolitan zone) in comparison to other sub-basins. Samples were generally grouped according to their geographical location. Bacterial classes Alphaproteobacteria, Bacteroidia, Campylobacteria, Fusobacteriia, and Gammaproteobacteria were the most frequent along the river. Arcobacter cryaerophilus (Campylobacteria) was the most frequent species in the Lower Rimac while Flavobacterium succinicans (Bacteroidia) and Hypnocyclicus (Fusobacteriia) were the most predominant in the Upper Rimac. Predicted metabolic functions in the microbiota include bacterial motility and quorum sensing. Additional metabolomic analyses showed the presence of some insecticides and herbicides in the Parac-Upper Rimac and Santa Eulalia-Parac sub-basins. The dominance in the Metropolitan area of Arcobacter cryaerophilus, an emergent pathogen associated with fecal contamination and antibiotic multiresistance, that is not usually reported in traditional microbiological quality assessments, highlights the necessity to apply next-generation sequencing tools to improve pathogen surveillance. We believe that our study will encourage the integration of omics sciences in Peru and its application on current environmental and public health issues.

Next generation sequencing approaches to evaluate water and wastewater quality

The emergence of next generation sequencing (NGS) is revolutionizing the potential to address complex microbiological challenges in the water industry. NGS technologies can provide holistic insight into microbial communities and their functional capacities in water and wastewater systems, thus eliminating the need to develop a new assay for each target organism or gene. However, several barriers have hampered wide-scale adoption of NGS by the water industry, including cost, need for specialized expertise and equipment, challenges with data analysis and interpretation, lack of standardized methods, and the rapid pace of development of new technologies. In this critical review, we provide an overview of the current state of the science of NGS technologies as they apply to water, wastewater, and recycled water. In addition, a systematic literature review was conducted in which we identified over 600 peer-reviewed journal articles on this topic and summarized their contributions to six key areas relevant to the water and wastewater fields: taxonomic classification and pathogen detection, functional and catabolic gene characterization, antimicrobial resistance (AMR) profiling, bacterial toxicity characterization, Cyanobacteria and harmful algal bloom identification, and virus characterization. For each application, we have presented key trends, noteworthy advancements, and proposed future directions. Finally, key needs to advance NGS technologies for broader application in water and wastewater fields are assessed.

Improved culture enrichment broth for isolation of Arcobacter-like species from the marine environment

Arcobacter-like species are found associated with many matrices, including shellfish in marine environments. The culture media and conditions play a major role in the recovery of new Arcobacter-like species. This study was aimed to develop a culture media for isolation and enhanced growth of Arcobacter-like spp. from marine and shellfish matrices. For this purpose, 14 different Arcobacter-like spp. mostly isolated from shellfish, were grown in 24 different formulations of enrichment broths. The enrichment broths consisted of five main groups based on the organic contents (fresh oyster homogenate, lyophilized oyster either alone or in combination with other standard media), combined with artificial seawater (ASW) or 2.5% NaCl. Optical density (OD_420nm) measurements after every 24 h were compared with the growth in control media (Arcobacter broth) in parallel. The mean and standard deviation were calculated for each species in each broth and statistical differences (p < 0.05) among broths were calculated by ANOVA. The results indicated that shellfish-associated Arcobacter-like species growth was significantly higher in Arcobacter broth + 50% ASW and the same media supplemented with lyophilized oysters. This is the first study to have used fresh or lyophilized oyster flesh in the enrichment broth for isolation of shellfish-associated Arcobacter-like spp.

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

Urban rivers affected by anthropogenic activities can act as reservoirs of antibiotic resistance genes (ARGs). This study aimed to describe the occurrence of selected ARGs (blaTEM, ermF, mecA, and tetA) and a class 1 integron (intI1) in an urban river in Nepal. A total of 18 water samples were collected periodically from upstream, midstream, and downstream sites along the Bagmati River over a 1-year period. All ARGs except mecA and intI1 were consistently detected by a quantitative polymerase chain reaction in the midstream and downstream sites, with concentrations ranging from 3.1 to 7.8 log copies/mL. ARG abundance was significantly lower at the upstream site (p < 0.05), reflecting the impact of anthropogenic activities on increasing concentrations of ARGs at midstream and downstream sites. Our findings demonstrate the presence of clinically relevant ARGs in the urban river water of Nepal, suggesting a need for mitigating strategies to prevent the spread of antibiotic resistance in the environment.

Intestinal Microbiota of Grass Carp Fed Faba Beans: A Comparative Study

Many reports of the intestinal microbiota of grass carp have addressed the microbial response to diet or starvation or the effect of microbes on metabolism; however, the intestinal microbiota of crisp grass carp has yet to be elucidated. Moreover, the specific bacteria that play a role in the crispiness of grass carp fed faba beans have not been elucidated. In the present study, 16S sequencing was carried out to compare the intestinal microbiota in the fore-, mid- and hind-intestine segments of grass carp following feeding with either faba beans or formula feed. Our results showed that (1) the hind-intestine presented significant differences in diversity relative to the fore- or midintestine and (2) faba beans significantly increased the diversity of intestinal microbiota, changed the intestinal microbiota structure (Fusobacteria was reduced from 64.26% to 18.24%, while Proteobacteria was significantly increased from 17.75% to 51.99%), and decreased the metabolism of energy, cofactors and vitamins in grass carp. Furthermore, at the genus and species levels, Acinetobacter accounted for 15.09% of the microbiota, and Acinetobacter johnsonii and Acinetobacter radioresistens constituted 3.41% and 2.99%, respectively, which indicated that Acinetobacter of the family Moraxellaceae contributed to changes in the intestinal microbiota structure and could be used as a potential biomarker. These results may provide clues at the intestinal microbiota level to understanding the mechanism underlying the crispiness of grass carp fed faba beans.