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The overuse of antibiotics has resulted in the prevalence of antibiotic resistance genes (ARGs) and antibiotic resistance bacteria (ARB) in the environment. High-density livestock farming is one of the major industries for antibiotic overuse. In this study, we sampled wastewater and manure at different stages of the feces treatment process from a dairy farm, as well as the soil in the farmland where the treated wastewater was being used for irrigation purpose. High-throughput Illumina sequencing was used to analyze the profiles of bacteria communities and ARGs. The results showed that the main ARG types were multidrug, aminoglycoside, glycopeptide, and tetracycline resistance genes, and Actinobacteria, Proteobacteria and Firmicutes were the main host bacteria phyla of these ARGs. The genus Nocardioides sp. and Ornithinimicrobium sp. were closely associated with the ARGs in the investigated samples. The relative abundances of ARGs in wastewater and manure were reduced by 68.5% and 62.1%, respectively, by the existing feces treatment process. Anaerobic fermentation and high-temperature fermentation were the most efficient treatment steps; the relative abundances of ARGs were reduced by 29.3% and 33.6% in the treated wastewater and manure, respectively. Irrigation with the treated wastewater significantly increased the abundance and diversity of ARGs and ARB in the surface soil of the farmland. The residual ARGs were found to transit through vertical gene transfer (VGT) and horizontal gene transfer (HGT) in soil. Therefore, the direct application of this inadequately treated wastewater and/or manure could risk spreading ARGs into the environment, and potentially impact human health. In order to effectively restrain the spread of ARGs, it is necessary to modify the wastewater and manure treatment processes and improve the regulations and guidelines of applying treated wastewater for irrigation. [ABSTRACT FROM AUTHOR]

To investigate the physicochemical conditions necessary to stably remove antibiotic-resistant bacteria (ARB) via contact with activated sludge (AS), the adhesion of ciprofloxacin (CIP)-resistant and -susceptible Escherichia coli to AS was simulated by contact tests in the laboratory. The CIP-resistant E. coli and susceptible E. coli were removed by a 3 log smaller concentration by a 5 h contact test at maximum. Considering the hydraulic retention time of a reaction tank (∼5 h) and step-feeding operation, we considered the removal rate of E. coli in the current simulated contact test to be in agreement with the actual situation where 1–2 log concentrations of E. coli were reported to be removed from an AS reaction tank. With the increase in the AS concentration and/or dissolved oxygen, the removal rate of E. coli increased. The removal rate of CIP-resistant E. coli was greater than that of susceptible E. coli under all experimental conditions. Although the mechanism by which CIP-resistant E. coli preferably adhered to AS was not clearly understood in detail, finding optimum conditions under which bacteria, including ARB, were efficiently removed by the AS process may be possible. HIGHLIGHTS Activated sludge (AS) effectively (>99%) adhered to Escherichia coli (E. coli) and ciprofloxacin (CIP)-resistant E. coli in 5 h.; The selective removal of CIP-resistant E. coli was quantitatively demonstrated as the possible outcome.; Removal rates of E. coli by adhesion increased with the AS concentrations and dissolved oxygen.; Stirring was imperative to ensure contact between E. coli and AS, but extremely high shear stress inhibited it.;

Evolutionary changes in microorganisms, in response to the current environment, can contribute generically to adaptations that have harmful effects on human welfare. Antibacterial resistance is one of the results of genetic and evolutionary changes in microorganisms. Many bacteria have developed resistance to antibiotics. Recently, most researchers have been focused on overcoming this problem, relying on nanoparticle-based drug delivery. In this study, our aim is to synthesize silver-doped fucoidan nanoparticle using Tridax procumbens plant leaf aqueous extract and examine their biological efficacy. We synthesized silver-doped fucoidan with the aqueous extraction of Tridax procumbens using the titration method. The synthesized nanoparticles were characterized, including UV-spectroscopy, SEM, FT-IR, EDX, and XRD. Furthermore, we assessed the efficacy of the nanoparticles in terms of antioxidant activity using the DHHP assay, anti-inflammatory activity using the protein degradation assay, and antibacterial activity using well diffusion method. Our result revealed that the synthesized nanoparticles were doped with Ag2+ in fucoidan using the plant extract. We observed a peak at 390 nm in the UV-spectra analysis, indicating the presence of silver nanoparticles. Further analysis, like SEM, FT-IR, EDX, and XRD showed the nanoparticle characterization. Moreover, these nanoparticles demonstrate good antioxidant and anti-inflammatory activity. Additionally, the nanoparticles exhibited antimicrobial activity against antibiotic-resistance bacteria. Finally, our synthesized silver-doped nanoparticles mediated by an aqueous extract of Tridax procumbens show potential in therapeutic aspects for bacterial infection. [ABSTRACT FROM AUTHOR]

Antibiotic fermentation residue (AFR) is nutrient-rich solid waste generated from fermentative antibiotic production process. It is demonstrated that AFR contains high-concentration of remaining antibiotics, and thus may promote antibiotic resistance development in receiving environment or feeding farmed animals. However, the dominate microorganisms and antibiotic resistance genes (ARGs) in AFRs have not been adequately explored, hampering understanding on the potential antibiotic resistance risk development caused by AFRs. Herein, seven kinds of representative AFRs along their production, storage, and treatment processes were collected, and multiple methods including amplicon sequencing, metagenomic sequencing, and bioinformatic approaches were adopted to explore the biological characteristics of AFRs. As expected, antibiotic fermentation producer was found as the predominant species in raw AFRs, which were collected at the outlet of fermentation tanks. However, except for producer species, more environment-derived species persisted in stored AFRs, which were temporarily stored at a semi-open space. Lactobacillus genus, classified as Firmicutes phylum and Bacilli class, became predominant bacterial taxa in stored AFRs, which might attribute to its tolerance to high concentration of antibiotics. Results from metagenomic sequencing together with assembly and binning approaches showed that these newly-colonizing species (e.g., Lactobacillus genus) tended to carry ARGs conferring resistance to the remaining antibiotic. However, after thermal treatment, remaining antibiotic could be efficiently removed from AFRs, and microorganisms together with DNA could be strongly destroyed. In sum, the main risk from the AFRs was the remaining antibiotic, while environment-derived bacteria which tolerate extreme environment, survived in ARFs with high content antibiotics, and may carry ARGs. Thus, hydrothermal or other harmless treatment technologies are recommended to remove antibiotic content and inactivate bacteria before recycling of AFRs in pharmaceutical industry. [Display omitted] [ABSTRACT FROM AUTHOR]

ABSTRACTThe emergence of antibiotic-resistant bacteria (ARB) caused by the overuse of antibiotics severely threatens human health. Hospital sewage may be a key transmission hub for ARB. However, the complex link between the microbiome and resistomeresistance in hospital sewage remains unclear. In this study, metagenomic assembly and binning methods were used to investigate the microbial community, resistome, and association of antibiotic resistance genes (ARGs) with ARB in sewage from 10 representative sites (outpatient building, surgery building, internal medicine buildings [IMB1-4], staff dormitory, laboratory animal building, tuberculosis building [TBB], and hospital wastewater treatment plant) of a hospital in Shanghai from June 2021 to February 2022. A total of 252 ARG subtypes, belonging to 17 antibiotic classes, were identified. The relative abundance of KPC-2 was higher at IMBs and TBB than at other sites. Of the ARG-carrying contigs, 47.3%-62.6% were associated with mobile genetic elements, and the proportion of plasmid-associated ARGs was significantly higher than that of chromosome-associated ARGs. Although a similar microbiome composition was shared, certain bacteria were enriched at different sites. Potential pathogens Enterococcus B faecium and Klebsiella pneumoniae were primarily enriched in IMB2 and IMB4, respectively. The same ARGs were identified in diverse bacterial hosts (especially pathogenic bacteria), and accordingly, the latter possessed multiple ARGs. Furthermore, gene flow was frequently observed in the sewage of different buildings. The results provide crucial information on the characterization profiles of resistomes in hospital sewage in Shanghai.IMPORTANCEEnvironmental antibiotic resistance genes (ARGs) play a critical role in the emergence and spread of antimicrobial resistance, which poses a global health threat. Wastewater from healthcare facilities serves as a significant reservoir for ARGs. Here, we characterized the microbial community along with the resistome (comprising all antibiotic resistance genes) in wastewater from a specialized hospital for infectious diseases in Shanghai. Potential pathogenic bacteria (e.g., Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Enterococcus B faecium) were frequently detected in hospital wastewater and carried multiple ARGs. A complex link between microbiome and resistome was observed in the wastewater of this hospital. The monitoring of ARGs and antibiotic-resistant bacteria (ARB) in hospital wastewater might be of great significance for preventing the spread of ARB.

Background: While concerns about the spread of Antimicrobial resistance (AMR) in HCF have long been identified, the links with environmental issues - such as water, sanitation, and hygiene (WASH) - are much less well understood. Indeed, misperceptions of links between WASH and AMR are identified as one of the hindrances of infection control programs. This study assessed the gap in knowledge in healthcare facilities (HCFs), by analyzing the perceptions of healthcare workers. Methods: A cross-sectional survey was conducted in governmental primary healthcare facilities in Gaza, Palestine between April and August 2022. Out of 1802 workers, 322 were randomly recruited to fill out a self-administer questionnaire. The workers were representing both genders (50.3% females) and aged between (19- 60 years). Data was analyzed using Statistical Package for Social Sciences (SPSS) software, version 23. Results: About half of the respondents (52.5%) did not know what the "WASH" term stands for, and nearly a quarter (22.7%) were unable to define AMR bacteria correctly. The perception of water safety was higher for domestic (66.1%) than for drinking water (54.7%) with a lower perception among females (p value=0.005) and medical staff (p value=0.000). At HCFs, only 40.7% of respondents had the perception that regular water safety monitoring occurs and 30.4% declared that water pollution was reported at their facilities. Only 20.0% of health workers think that they play a role in monitoring water safety and 24.8% think that they play a role in preventing and controlling AMR bacteria. Conclusion: Hybrid educational and awareness programs about water safety and prevention of AMR bacteria need to be implemented within the context of the One Health approach. The investment in WASH infrastructure at HCFs requires parallel investment in capacity building and raising awareness of workers. [ABSTRACT FROM AUTHOR]

The present study was aimed to obtain a close insight into the distribution and diversity of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) among the aquatic products collected in Zhejiang, China. A total of 136 presumptive ARB picked up from six aquatic samples were classified into 22 genera and 49 species based on the 16S rDNA sequencing. Aeromonas spp., Shewanella spp., Acinetobacter spp., Myroides spp., Pseudomonas spp., and Citrobacter spp. accounted for 80% of the ARB. Among them, 109 isolates (80.15%) exhibited resistance to at least one antibiotic. Most isolates showed resistance to not only the originally selected drug but also to one to three other tested drugs. The diversity of ARB distributed in different aquatic products was significant. Furthermore, the resistance data obtained from genotypic tests were not entirely consistent with the results of the phenotypic evaluation. The genes qnrS, tetA, floR, and cmlA were frequently detected in their corresponding phenotypic resistant isolates. In contrast, the genes sul2, aac(6’)-Ib, and blaPSE were less frequently found in the corresponding phenotypically resistant strains. The high diversity and detection rate of ARB and ARGs in aquaculture might be a significant threat to the food chains closely related to human health.

The mechanism of antibiotic resistance (AR) development in an activated sludge system under tetracycline (TC) pressure was discussed and analyzed. According to the variation of macro-factors, including TC, COD, TN, TP, NH3-N, pH, heavy metals, and reactor settings, the tet genes respond accordingly. Consequently, the enrichment sites of tet genes form an invisible AR selection zone, where AR microorganisms thrive, gather, reproduce, and spread. The efflux pump genes tetA and tetB prefer anaerobic environment, while ribosome protective protein genes tetM, tetO, tetQ, tetT, and tetW were more concentrated in aerobic situations. As a corresponding micro-effect, different types of tet genes selected the corresponding dominant bacteria such as Thauera and Arthrobacter, suggesting the intrinsic relationship between tet genes and potential hosts. In summary, the macro-response and micro-effect of tet genes constitute an interactive mechanism with tet genes as the core, which is the crucial cause for the continuous development of AR. This study provides an executable strategy to control the development of AR in actual wastewater treatment plants from the perspective of macro-factors and micro-effects. [ABSTRACT FROM AUTHOR]

Water quality monitoring of a particular river is crucially important to determine if the river water meets the requirement for its designated uses. Therefore, an assessment of the physiochemical water quality at Satow Waterfall, Sarawak, and the prevalence of antibiotic-resistant bacteria (ARB) was conducted to corroborate the safety of the water from the waterfall. A total of 42 water samples were collected at the subsurface water of the upstream, midstream, and downstream on two sampling trips in June 2021 (dry season) and December 2021 (wet season), with six months intervals. The water quality index (WQI) of the sampling stations ranged from 92.60 to 95, classifying the water under Class I. However, the water is microbiologically polluted, with the highest coliform count of 2.59 × 105 CFU/ mL recorded at the middle stream during the wet season, which has surpassed the regulatory standard set by the Malaysian Department of Environment (DOE). A total of 54 bacterial isolates were chosen as representatives and identified by 16S rRNA sequencing, which confirmed the existence of 21 bacterial genera. All identified isolates were tested against 15 antibiotics of various classes employing the Clinical and Laboratory Standards Institute (CLSI) protocols. The antibiotic susceptibility test (AST) demonstrated substantial resistance to sulfamethoxazole (48%) and erythromycin (48%), as well as high susceptibility to chloramphenicol (84%), levofloxacin (60%) and ofloxacin (60%). The Multiple Antibiotic Resistance Index (MARI) evaluations demonstrated the MARI varied from 0-0.60, with 33% of the isolates having a MARI greater than 0.2. In this study, the occurrence of ARB in a water environment where there is an undisclosed source of antibiotic utilization is still inevitable, highlighting the necessity to constantly monitor the water quality and the pervasiveness of ARB in recreational water. [ABSTRACT FROM AUTHOR]

The presence of antibiotic-resistant bacteria (ARB) in receiving water can severely threaten the aquatic environment and human health. The treated effluent containing ARB in some livestock wastewater treatment plants (WWTPs) is returned to the municipal WWTP to reduce the residual ammonia and phosphorus concentrations. ARBs are widespread through wastewater treatment processes and are discharged into river and lake. This study highlights that the isolated lytic phage could reduce ARB isolated from livestock WWTPs and apply phage-based biocontrol in mixed cultures. ARB and lytic phages were isolated from livestock wastewater and used in a batch reactor with diverse cultures. The isolated bacterium was from the Aeromonas species and was resistant to various antibiotics (penicillin, tetracycline, colistin, and kanamycin), indicating multi-drug resistance and biofilm formation. The isolated lytic phage successfully infected Aeromonas species in pure culture and was relatively stable in terms of pH, temperature, and toxic chemicals. The multiplicity of infection (MOI) was examined to determine the proper phage number to kill the host bacterium. The optimal number to control the isolated ARB was a 1:100 phage-to-host ratio. Scanning electron microscopy showed that lytic phages reduced bacterial growth and biofilm formation. Phage-mediated biocontrol was applied in a batch reactor with mixed cultures. Pyrosequencing data from the batch reactor indicated that lytic phages reduced the proportion of the isolated ARB from 65.7 to 20% in 24 h. This study provides evidence for the possible application of lytic phages to control ARB in treated wastewater and an alternative method to prevent the widespread exposure of ARB without producing chemical byproducts. [ABSTRACT FROM AUTHOR]

This study investigates the antibiotic resistance fate in the urban water cycle, evaluating the dynamics of antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) in three different full-scale wastewater treatment plants (WWTPs) and two drinking water treatment plants (DWTPs) located in the same geographical area (North-West of Italy). ARB (tetracycline-, ampicillin-, and sulfonamide-resistant bacteria) were quantified by plate counting and the abundances of selected ARGs (i.e., tetA, blaTEM, and sulII) and intI1 gene were measured using quantitative real-time PCR (qPCR). Higher concentrations of ARB and ARGs were observed in the WWTPs with respect to the DWTPs identifying the WWTP as hotspot for the spread of antibiotic resistances. Although a significant reduction of ARB and ARGs was observed in WWTPs and DWTPs after the treatment, none of the detected ARB or ARGs was completely removed in drinking water. The stability of the antibiotic-resistant rates between inlet and outlet associated with the reduction of relative ARG abundances underlined that both the treatments (WWTs and DWTs) did not apply any selective pressure. The overall results highlighted the importance to investigate the antibiotic resistance dynamics in aquatic ecosystems involved in urban water cycle integrating the information obtained by culture-dependent method with the culture-independent one and the need to monitor the presence of ARB and ARGs mainly in drinking water that represents a potential route of transmission to human. [ABSTRACT FROM AUTHOR]

Antibiotic resistance (AR) is a critical global health issue with significant clinical and economic implications. AR occurs when microorganisms develop mechanisms to withstand the effects of antibiotics, reducing treatment efficacy and increasing the risk of mortality and healthcare costs. While the connection between antibiotic use in clinical and agricultural settings and the emergence of AR is well-established, the role of urban soils as reservoirs and spreaders of AR is underexplored. This review examines the complex dynamics of AR in urban soils, highlighting the various sources of antibiotics, including domestic wastewater, industrial effluents, urban agricultural practices, but also microplastics and domestic animal excrements. The selective pressure exerted by these anthropogenic sources promotes the proliferation of antibiotic-resistant bacteria, particularly through horizontal gene transfer, which facilitates the transmission of resistance genes among soil microorganisms in urban environments. About that, the presence of antibiotics in urban soils poses a significant threat to public health by potentially transferring resistance genes to human pathogens through multiple pathways, including direct contact, food consumption, and water ingestion. Furthermore, AR in urban soils disrupts microbial community dynamics, impacting soil fertility, plant growth, and overall environmental quality. Therefore, this review aims to address gaps in understanding AR in urban soils, offering insights into its implications for human health and ecosystem integrity. By identifying these gaps and suggesting evidence-based strategies, this review proposes valid and sustainable solutions to mitigate and counteract the spread of AR in urban environments. [ABSTRACT FROM AUTHOR]

Antibiotic resistance is currently one of the greatest threats to human health. Widespread use and residues of antibiotics in humans, animals, and the environment can exert selective pressure on antibiotic resistance bacteria (ARB) and antibiotic resistance gene (ARG), accelerating the flow of antibiotic resistance. As ARG spreads to the population, the burden of antibiotic resistance in humans increases, which may have potential health effects on people. Therefore, it is critical to mitigate the spread of antibiotic resistance to humans and reduce the load of antibiotic resistance in humans. This review briefly described the information of global antibiotic consumption information and national action plans (NAPs) to combat antibiotic resistance and provided a set of feasible control strategies for the transmission of ARB and ARG to humans in three areas including (a) Reducing the colonization capacity of exogenous ARB, (b) Enhancing human colonization resistance and mitigating the horizontal gene transfer (HGT) of ARG, (c) Reversing ARB antibiotic resistance. With the hope of achieving interdisciplinary one-health prevention and control of bacterial resistance.

Antibiotic resistance bacteria (ARB) and antibiotic resistance genes (ARGs) are emerging contaminants posing risk to human health. To investigate the pathogenic ARBs and the horizontal gene transfer (HGT) via both extracellular ARGs (eARGs) and intracellular ARGs (iARGs), an in vitro digestion simulation system was established to monitoring the ARB and ARGs passing through the artificial digestive tract. The results showed that ARB was mostly affected by the acidity of the gastric fluid with about 99% ARB (total population of 2.45 × 109–2.54 × 109) killed at pH 2.0 and severe damage of bacterial cell membrane. However, more than 80% ARB (total population of 2.71 × 109–3.90 × 109) survived the challenge when the pH of the gastric fluid was 3.0 and above. Most ARB died from the high acidity, but its ARGs, intI1 and 16 S rRNA could be detected. The eARGs (accounting for 0.03–24.56% of total genes) were less than iARGs obviously. The eARGs showed greater HGT potential than that of iARGs, suggesting that transformation occurred more easily than conjugation. The transferring potential followed: tet (100%) > sul (75%) > bla (58%), related to the high correlation of intI1 with tetA and sul2 (p

The adsorption efficiency of different Ag/ZnO heterostructures was investigated for the removal of multidrug‐resistant Enterococcus faecium (MDR_EF) harboring multiple resistance genes from tap‐water. The concentration of the precursors influences the microstructures of the adsorbents; however, it did not significantly affect the adsorption efficiency. The maximum adsorption capacity, qe, (34.11 CFU/g), was obtained for Ag1Zn3.5. The kinetic studies revealed that Ag1Zn1 and Ag1Zn2 adsorbents agreed to the pseudo‐first‐order kinetic equation and adsorbents Ag2Zn1, Ag3.5Zn1 and Ag1Zn3.5 agreed to the pseudo‐second‐order kinetic equation. Initial tap‐water pH range was beneficial for the adsorption and the pH of the treated tap‐water was within the WHO tap water recommendation (6.5–8.5), whereas the effect of ionic strength, anionic and cationic interference was insignificant in the adsorption of MDR_EF onto the different heterostructure. Interestingly, the MDR_EF could retain its cell membrane integrity and resistance genes, suggesting that surface adsorption was the primary mechanism for the removal. [ABSTRACT FROM AUTHOR]

Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are emerging contaminants leading to severe worldwide health problems. Chlorination, a widely used procedure, was extensively explored as one of the main methods to remove ARB and ARGs in recent years. In this study, to enrich the analyses of chlorination, several comprehensive effects of the chlorine disinfection system on ARB and their conjugative transfer ability were explored. The results presented that the low dose of chlorine (<3-log inactivation rate) had little influence on the survival of bacteria in terms of their capacity for conjugative transfer and antibiotic resistance. The high dose of chlorine (>3-log inactivation rate) triggered cell membrane changes, with little influence on the bacteria in terms of their antibiotic resistance. However, their capacity for conjugative transfer sharply decreased. Minor consumption of chloramphenicol was achieved with the chlorine dose applied in the disinfection system. Monochloroacetonitrile (MCAN) had limited effects on the frequency of conjugative transfer, indicating that the existence of MCAN would not aggravate the dissemination of ARGs by conjugative transfer. The overall impacts of the chlorine disinfection system with different containments on antibiotic resistance need further investigation. [ABSTRACT FROM AUTHOR]

The emergence of antibiotic resistant bacteria in the aquatic environment has led to an increase in waterborne health risks to an alarming extent. This study attempts to investigate the population of certain antibiotic resistant strains in Peninsular Malaysia. From the samples of 14 rivers from 7 different states, 203 isolates were successfully isolated. These were from rivers in Negeri Sembilan, Melaka, Selan-gor, Kuala Lumpur, Kedah, Kelantan and Terengganu with 35, 15, 37, 39, 24, 26 and 27 isolates, respectively. The isolates were tested for their susceptibility to-wards 6 broad spectrumsof antibiotics which are gentamicin, ampicillin, rifam-picin, chloramphenicol, tetracycline, and ciprofloxacin. Out of the 203 isolates, 117 isolates were identified to have more than 20% MAR index value,with 47 of the isolates possess a minimum 50% MAR index value. Based on MAR index value, 59% of the isolates are high risk threats indicating a seriousemergence of antibiotic resistant bacteria in the rivers in Peninsular Malaysia. Isolates with MAR index value of more than 50% were selected for 16S rRNA gene sequencing for further identification. Based on 16s rRNA gene sequencing, the isolates are a mixture of pathogenic and commensals bacteria, implying that the environment, especially rivers,can be a reservoir for genetic jugglery.

This study investigated the short-term impact of irrigation with Amoxicillin solutions on the presence of the amoxicillin-resistance trait among culturable soil heterotrophic aerobic bacteria. The microcosm experimental design consisted of 15 days of incubation of 10 g soil samples irrigated daily with distilled water containing increasing doses of amoxicillin (0, 0.1, 1, 10, 100, 1000 µg g-1 of soil day-1). The hypothesis was that continuous daily addition of antibiotics would increase the proportion of antibiotic-resistant bacteria in soils. After the incubation period, the total and antibiotic resistance heterotrophic aerobic bacteria communities were assessed through serial dilution of soil suspensions, followed by agar plate culture enumeration, isolation, identification and microscopy observation. The presence of antibiotic-resistant bacteria was also evaluated directly on treated wastewater used for field irrigation before this microcosm study to assess the amoxicillin-resistant bacteria bioaugmentation hypothesis. Results indicated that the Amoxicillin resistance was widespread among bacteria present in both treated wastewater used for irrigation and in the receiving soil. A microcosm experiment was attempted as a 'proof of concept' to demonstrate that irrigation with treated wastewater containing antibiotics would exert selective pressure and promote the proliferation of antibiotic resistance bacteria. Unexpectedly, the results from the microcosm incubations indicated the daily addition of amoxicillin did not increase bacterial antibiotic resistance trait abundance in soils, which even significantly decreased for all tested doses. The antibiotic-resistant species identified among the isolates were Pseudomonas mosselii, P. otitidis, P. mendocina, P. flavescens, Stenotrophomnas maltophilia, Bacillus thuringiensis, Aeromonas veronii, Candida parapsilosis, Streptomyces violaceoruber and Microbacterium barkeri. [ABSTRACT FROM AUTHOR]

Farmers apply broiler chicken litter to soils to enrich organic matter and provide crops with nutrients, following varying periods of stockpiling. However, litter frequently harbors fecal-derived microbial pathogens and associated antibiotic resistance genes (ARGs), and may be a source of microbial contamination of produce. We coupled a cutting-edge Loop Genomics long-read 16S rRNA amplicon-sequencing platform with high-throughput qPCR that targeted a suite of ARGs, to assess temporal (five time points over a 60-day period) and spatial (top, middle and bottom layers) microbiome and resistome dynamics in a broiler litter stockpile. We focused on potentially pathogenic species from the Enterobacteriaceae, Enterococcaceae and Staphylococcaceae families associated with food-borne disease. Bacterial diversity was significantly lower in the middle of the stockpile, where targeted pathogens were lowest and Bacillaceae were abundant. E. coli was the most abundant Enterobacteriaceae species, and high levels of the opportunistic pathogen Enterococcus faecium were detected. Correlation analyses revealed that the latter was significantly associated with aminoglycoside (aac(6′)-Ib(aka aacA4), aadA5), tetracycline (tetG), vancomycin (vanC), phenicol (floR) and MLSB (mphB) resistance genes. Staphylococcaceae were primarily non-pathogenic, but extremely low levels of the opportunistic pathogen S. aureus were detected, as was the opportunistic pathogen S. saprophyticus, which was linked to vancomycin (vanSA, vanC1), MLSB (vatE, ermB) and tetracycline (tetK) resistance genes. Collectively, we found that stockpile microbiomes and resistomes are strongly dictated by temporal fluctuations and spatial heterogeneity. Insights from this study can be exploited to improve stockpile management practice to support sustainable antimicrobial resistance mitigation policies in the future.

Pond aquaculture has become the most important and broadest breeding model in China, and an extremely important source of aquatic products, but the potential hazard factors of potential pathogenic bacteria (PPB), antibiotic resistance bacteria (ARB), and antibiotic resistance genes (ARGs) in aquaculture environment are largely invisible. In the present study, the bacterial communities in the larvae, juvenile, rearing, and harvesting culture stages of great grass carp (Ctenopharyngodon idellus) ponds were investigated and the structure of microbial flora analysis showed that the larvae culture stage has the highest abundance and the most dominant phyla were Proteobacteria (27.8%). A total of 123 significant Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotations and the relative abundance of nine bacterial phenotypes implied that the larvae culture stage had the most abundance of pathogenic potential and mobile elements. The correlation analyses of environmental factors showed that temperature, stocking density, pH, and transparency showed the significant impacts on both the distribution of microbiome and the PPB. More importantly, a total of 40 ARB were identified, and 16 ARGs have the detection rates of 100%, which revealed that they are widely distributed and highly enriched in the aquaculture production. Notably, this is the first robust report to analyze and understand the PPB, ARB, and ARGs characteristics and dynamic changes in the pond aquaculture. [ABSTRACT FROM AUTHOR]

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The biofilms comprise a population of bacteria with a varying variety of polysaccharides, proteins and DNA. Bacterial multi-phase defence consists of low antibiotic absorption, sluggish replication in the biofilm, and adaptive stress response. This antibiotic resistance produced by biofilm makes it challenging to deal with bacteria with effective antibiotic dosages in planktonic forms. A crucial component in the virulent colonisation of live tissues or medical equipment is having favourable situation for bacteria to create biofilms. The high level of recalcitrance in biofilm populations is due to several molecular pathways. As the stock of effective antibiotics is depleting, bacterial resistance is becoming an increasing risk to public health. As a result, new antibiotics are urgently needed. This review includes current empirical findings related to antibiotic resistance in biofilms and summarises the biofilm resistance and tolerance mechanisms.

The biofilms comprise a population of bacteria with a varying variety of polysaccharides, proteins and DNA. Bacterial multi-phase defence consists of low antibiotic absorption, sluggish replication in the biofilm, and adaptive stress response. This antibiotic resistance produced by biofilm makes it challenging to deal with bacteria with effective antibiotic dosages in planktonic forms. A crucial component in the virulent colonisation of live tissues or medical equipment is having favourable situation for bacteria to create biofilms. The high level of recalcitrance in biofilm populations is due to several molecular pathways. As the stock of effective antibiotics is depleting, bacterial resistance is becoming an increasing risk to public health. As a result, new antibiotics are urgently needed. This review includes current empirical findings related to antibiotic resistance in biofilms and summarises the biofilm resistance and tolerance mechanisms. [ABSTRACT FROM AUTHOR]

The emergence of antibiotic resistant bacteria in the aquatic environment has led to an increase in waterborne health risks to an alarming extent. This study attempts to investigate the population of certain antibiotic resistant strains in Peninsular Malaysia. From the samples of 14 rivers from 7 different states, 203 isolates were successfully isolated. These were from rivers in Negeri Sembilan, Melaka, Selangor, Kuala Lumpur, Kedah, Kelantan and Terengganu with 35, 15, 37, 39, 24, 26 and 27 isolates, respectively. The isolates were tested for their susceptibility towards 6 broad spectrums of antibiotics which are gentamicin, ampicillin, rifampicin, chloramphenicol, tetracycline, and ciprofloxacin. Out of the 203 isolates, 117 isolates were identified to have more than 20% MAR index value, with 47 of the isolates possess a minimum 50% MAR index value. Based on MAR index value, 59% of the isolates are high risk threats indicating a serious emergence of antibiotic resistant bacteria in the rivers in Peninsular Malaysia. Isolates with MAR index value of more than 50% were selected for 16S rRNA gene sequencing for further identification. Based on 16s rRNA gene sequencing, the isolates are a mixture of pathogenic and commensals bacteria, implying that the environment, especially rivers, can be a reservoir for genetic jugglery. [ABSTRACT FROM AUTHOR]

Abstract Background Antibiotic resistance is a global public health threat. Water from human activities is collected at wastewater treatment plants where processes often do not sufficiently neutralize antibiotic resistant bacteria and genes, which are further shed into the local environment. This protocol outlines the steps to conduct a systematic review based on the Population, Exposure, Comparator and Outcome (PECO) framework, aiming at answering the question “Are antimicrobial-resistant enterobacteriaceae and antimicrobial resistance genes present (O) in air and water samples (P) taken either near or downstream or downwind or down-gradient from wastewater treatment plants (E), as compared to air and water samples taken either further away or upstream or upwind or up-gradient from such wastewater treatment plant (C)?” Presence of antimicrobial-resistant bacteria and genes will be quantitatively measured by extracting their prevalence or concentration, depending on the reviewed study. Methods We will search PubMed, EMBASE, the Cochrane database and Web of Science for original articles published from 1 Jan 2000 to 3 Sep 2018 with language restriction. Articles will undergo a relevance and a design screening process. Data from eligible articles will be extracted by two independent reviewers. Further, we will perform a risk of bias assessment using a decision matrix. We will synthesize and present results in narrative and tabular form and will perform a meta-analysis if heterogeneity of results allows it. Discussion Antibiotic resistance in environmental samples around wastewater treatment plants may pose a risk of exposure to workers and nearby residents. Results from the systematic review outlined in this protocol will allow to estimate the extend of exposure, to inform policy making and help to design future studies.

Antibiotic resistance is a great concern, which leads to global public health risks and ecological and environmental risks. The presence of antibiotic-resistant genes and antibiotic-resistant bacteria in the environment exacerbates the risk of spreading antibiotic resistance. Among them, horizontal gene transfer is an important mode in the spread of antibiotic resistance genes, and it is one of the reasons that the antibiotic resistance pollution has become increasingly serious. At the same time, free antibiotic resistance genes and resistance gene host bacterial also exist in the natural environment. They can not only affect horizontal gene transfer, but can also migrate and aggregate among environmental media in many ways and then continue to affect the proliferate and transfer of antibiotic resistance genes. All this shows the seriousness of antibiotic resistance pollution. Therefore, in this review, we reveal the sensitive factors affecting the distribution and spread of antibiotic resistance through three aspects: the influencing factors of horizontal gene transfer, the host bacteria of resistance genes and the migration of antibiotic resistance between environmental media. This review reveals the huge role of environmental migration in the spread of antibiotic resistance, and the environmental behavior of antibiotic resistance deserves wider attention. Meanwhile, extracellular antibiotic resistance genes and intracellular antibiotic resistance genes play different roles, so they should be studied separately. [ABSTRACT FROM AUTHOR]

Surface water contamination remains a major worldwide public health concern and may contribute to the dissemination of antibiotic-resistant bacteria. The current study dealt with the assessment of physicochemical parameters in the wastewater treatment plant in Almamierh, in the city of Babylon Province, Iraq. The treated water in this plant is used for agricultural purposes. To evaluate water quality, samples were collected from three sites (input, sedimentation, output) for estimation physicochemical parameters that includes (Water temperature, EC, PH, BOD, COD, TDS). the highest concentration recorded in the first site, especially BOD5 (235 Mg/L), COD (761 Mg/L), TDS (626.432 mg/L), while the EC was the highest value in the second location (1008ms/cm). These samples subjected to bacteriological analysis and a number of bacterial species have been isolated, such as: Escherichia coli, Klebsiella pneumonia, Enterococcus faecalis, pseudomonas aeruginosa. Isolates were tested for resistance to 12 classes of antibiotics, the results showed that the highest resistance levels were to β-lactam antibiotics, followed by penicillin, cephem, Fluoroquinolones, tetracycline, glycopeptides, and erythromycin. [ABSTRACT FROM AUTHOR]

Aim: Shiga toxin-producing Escherichia coli (STEC) represent a severe public health issue worldwide, causing life-threatening diseases in the human gastrointestinal tract. This study aimed to determine the occurrence of virulent and antibiotic-resistant STEC in retail meat and milk products and human stool samples and to characterize the genes encoding for virulence and antibiotic resistance among the identified STEC isolates. Materials and Methods: A total of 260 food samples were randomly collected from retail markets in different localities of El Giza Governorate, Egypt. 50 stool specimens were obtained from children that had diarrhea at Embaba Fever Hospital. All collected samples were initially subjected to bacteriological examination and serotyping, and then subsequently, the isolates were exposed to polymerase chain reaction application and sequencing for the identification of the virulence-related genes. Finally, the virulent STEC isolates were tested for antibiotic susceptibility. Results: Serotyping of the 76 biochemically identified isolates showed that 18 were STEC with a predominance of non- O157 (16) while 2 O157:K-serotype was detected only in one food and one human isolate. Molecular identification of the virulence genes illustrated that the minced meat showed the highest prevalence of STEC (8%) as compared to the other food products. In the humans, the O157 was the only serotype that expresses the Shiga toxin-associated gene (eaeA). Antibiotic susceptibility test displayed that 13 of the 17 food and human isolates (76.47%) were resistant to cephalothin (KF30). 9 of the 13 cephalothin-resistant isolates harbor the β lactamase (blaTEM)-resistant gene. All isolates were sensitive to chloramphenicol, ciprofloxacin, amikacin, and gentamicin. DNA sequencing and phylogenetic analysis of the stx2-positive minced meat isolate revealed a high genetic relatedness with beef minced meat from the USA and Australia. Conclusion: This study showed the predominance of non-O157 among the identified isolates. Minced meat showed the highest prevalence of STEC as compared to the other food products, and this work illustrates the necessity to consider the food products as a potential source of the non-O157 STEC serotypes. DNA sequencing and phylogenetic analysis revealed a high genetic relatedness with beef minced meat from the USA and Australia. This highlights the high probability of worldwide spread of such serotypes, signifying the importance of the one world concept.

Very little information on the occurrence and risk assessment of antibiotics in the aquatic environment is reported for Vietnam, where antibiotics are assumed to be omnipresent in urban canals and lakes at high concentrations due to the easy accessibility of antibiotics without doctor prescription. This study provides comprehensive analysis of the occurrence of 23 antibiotics in urban canals (To Lich and Kim Nguu) and lakes (West Lake, Hoan Kiem, and Yen So) in Hanoi, Vietnam. Of these 23 antibiotics, 18 were detected in urban canals at above 67.9% detection frequency (DF). The concentrations of detected antibiotics were in the range from below quantification limit (MQL) to almost 50,000 ng/L, depending on the compound and sampling site. In urban canals, median concentration of amoxicillin, erythromycin, and sulfamethoxazole was >1000 ng/L while other antibiotics such as ampicillin, chloramphenicol, clindamycin, sulfamethazine, tetracycline, tylosin and vancomycin were detected at median concentrations of <100 ng/L. Similarly, 16 target antibiotics were also detected in urban lakes. Macrolides (azithromycin, clarithromycin, and erythromycin-H 2 O), fluoroquinolones (enrofloxacin and ofloxacin), lincosamides (clindamycin and lincomycin), and trimethoprim were ubiquitously detected in urban lakes (DF = 100%). In this study, potential risks of antibiotics in the investigated urban canals and lakes were assessed based on the predicted no-effect concentration (PNEC) from the existing literature for antibiotic resistance selection (PNEC ARM) and ecological toxicity to aquatic organisms (PNEC Ecotox). Ampicillin, amoxicillin, azithromycin, ciprofloxacin, clarithromycin, enrofloxacin, erythromycin, ofloxacin, tetracycline, and trimethoprim were found in the investigated urban canals at concentrations exceeding their PNEC ARM and PNEC Ecotox. Similarly, most of the target antibiotics (i.e. amoxicillin, ciprofloxacin, clarithromycin, clindamycin, enrofloxacin, erythromycin, lincomycin, ofloxacin, sulfamethoxazole, tetracycline, trimethoprim and tylosin) were detected in the investigated urban lakes at concentrations close to or exceeding PNEC Ecotox for aquatic organisms. Further investigations on the occurrence and fate of antibiotic residues and antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in surface waters are recommended. Unlabelled Image • Comprehensive data on the occurrence of 23 antibiotics in surface water was provided. • Median concentration of AMX, ERY, and SMX in urban canals was >1000 ng/L. • Macrolides, fluoroquinolones and lincosamides were ubiquitously detected in urban lakes. • β-lactam, macrolides, fluoroquinolones in canals posed a possible risk for resistance selection. [ABSTRACT FROM AUTHOR]

Abstract Cruise ship wastewater discharges are pollution sources towards the marine environment that are poorly characterized. In this study, wastewater samples from cruise ships have been obtained during repair works in a shipyard. Different organic pollutants have been analyzed and their concentrations were similar to those in urban wastewaters for pharmaceuticals and fragrances, but higher for UV filters and PAHs. For the first time, cypermethrin, a pesticide highly toxic towards aquatic species, was found at relevant concentrations (>1 µg L^-1). The faecal microorganisms were for all parameters higher than 10^4 CFU 100 mL^-1, which together with the presence of antibiotic compounds in wastewater (e.g., triclosan), could potentially lead to the generation of antibiotic resistance bacteria (ARB). The historical position of cruise ships, determined from the Automatic Identification System (AIS), were used to define the time ships were underway, at port, or in repair. From ship's passenger and crew load, and from estimates of discharges the total volume of wastewater produced by these ships (371,000 m^3 year^-1) and the average flow (0.15 ± 0.03 m^3crew^-1 day^-1) were calculated. Highlights • A complete characterization of the wastewater of cruise ships has been made. • Cypermethrin, a pesticide highly toxic towards aquatic species, was found in cruise ships. • Faecal microbiological pollution was high, which together with antibiotics can lead to microbial resistance. • The volume of wastewater produced by cruises at shipyards worldwide is 371,000 m3 year−1. [ABSTRACT FROM AUTHOR]

Due to the global progress of antimicrobial resistance, the World Health Organization (WHO) published the list of the antibiotic-resistant “priority pathogens” in order to promote research and development of new antibiotics to the families of bacteria that cause severe and often deadly infections. In the framework of the One Health approach, the surveillance of these pathogens in different environments should be implemented in order to analyze their spread and the potential risk of transmission of antibiotic resistances by food and water. Therefore, the objective of this work was to determine the presence of high and critical priority pathogens included in the aforementioned list in different aquatic environments in the POCTEFA area (North Spain–South France). In addition to these pathogens, detection of colistin-resistant Enterobacteriaceae was included due its relevance as being the antibiotic of choice to treat infections caused by multidrug resistant bacteria (MDR). From the total of 80 analyzed samples, 100% of the wastewater treatment plants (WWTPs) and collectors (from hospitals and slaughterhouses) and 96.4% of the rivers, carried antibiotic resistant bacteria (ARB) against the tested antibiotics. Fifty-five (17.7%) of the isolates were identified as target microorganisms (high and critical priority pathogens of WHO list) and 58.2% (n = 32) of them came from WWTPs and collectors. Phenotypic and genotypic characterization showed that 96.4% were MDR and resistance to penicillins/cephalosporins was the most widespread. The presence of bla genes, KPC-type carbapenemases, mcr-1 and vanB genes has been confirmed. In summary, the presence of clinically relevant MDR bacteria in the studied aquatic environments demonstrates the need to improve surveillance and treatments of wastewaters from slaughterhouses, hospitals and WWTPs, in order to minimize the dispersion of resistance through the effluents of these areas.

Abstract Swine wastewater treatment plant has become one of the main sources of antibiotic resistance genes (ARGs). Membrane treatment processes are promising solutions for removal of the emerging contaminants. However, limited studies have investigated the effects of nanofiltration and reverse osmosis treatment in removing ARGs in swine wastewater. In this study, the presence and the fate of common ARGs including sul 1, sul 2, tet A, tet M and tet W, as well as intI 1 and 16S rRNA gene, were investigated in a medium-sized (6500) pig farm wastewater treatment plant (WWTP) equipped with conventional biological treatment and advanced membrane processing system. All of the genes were detected with highly abundance in the raw sewage. The biological treatments of the swine wastewater treatment plant did not reduce the quantity of the ARGs. As expected, nanofiltration and reverse osmosis treatment reduced the absolute gene copy number of ARGs efficiently (4.98–9.52 logs removal compared to raw sewage). Compared to the reverse osmosis effluent, however, the absolute abundance of ARGs in the artificial wetland increased by 1.00–2.06 logs. Meanwhile, the relative abundance of sulfonamide resistant genes were basically unchanged, while tetracycline resistance genes (tet A, tet M and tet W) decreased by 0.88, 3.47, 2.51 log, respectively. The results demonstrated that advanced membrane treatments are capable of removing various kinds of ARGs efficiently, as well as some common nitrogen and phosphorus contaminants. This study suggested a mature alternative method for the removal of ARGs from livestock wastewater. Graphical abstract Image 1 Highlights • Swine sewage presents high content of ARGs. • Nanofiltration and reverse osmosis reduces ARGs, nitrogen and phosphorus contaminants. • The abundance of ARGs in artificial wetland increased. [ABSTRACT FROM AUTHOR]

Abstract Soil contamination with antibiotics and antibiotic resistant bacteria/genes (ARB/ARGs) has becoming an emerging environmental problem. Moreover, the mixed pollutants' transfer and accumulation from soil to tuberous vegetables has posed a great threat against food security and human health. In this work, the application of two absorbing materials (maize biochar and sulfate modified eggshell) was able to reduce the poisonous effect of soil antibiotics on potato root system by stimulate the dissipation of water-soluble antibiotics in soil; and also improve food quality by increasing potato starch, protein, fat, and vitamins. Meanwhile, both amendments could effectively decrease the classes and the accumulative abundance of ARB and ARGs (sul I, sul II, cat I, cat II, erm A, erm B) in the edible parts of potato. The lowest abundance of ARGs was detected in the biochar application treatment, with the accumulative ARG level of 8.9 × 102 and 7.2 × 102 copies mL−1 in potato peel (sul l + cat I + erm A) and tuberous root (sul I), respectively. It is the first study to demonstrate the feasibility of biochar and eggshell derived from agricultural wastes as green absorbing materials to reduce soil antibiotic, ARB, and ARGs accumulation risk in tuberous vegetable. Graphical abstract Image 1 Highlights • Biochar or eggshell impeded soil antibiotics accumulation in potato effectively. • ARB isolates in potato decreased significantly after biochar or eggshell addition. • ARG accumulation risk was limited in potato with biochar or eggshell amendment. • Impedance effect of biochar was more effective than that of eggshell. • Biochar or eggshell application provided new strategy to ensure vegetable security. ARB and ARG accumulation risk was limited in potato with biochar or eggshell amendment; Impedance effect of biochar was more effective than that of eggshell. [ABSTRACT FROM AUTHOR]

Biological treatment processes at wastewater treatment plants (WWTPs), which are the most common methods of sewage treatment, could cause selective elimination and/or changes in the proportions of phenotypes/genotypes within bacterial populations in effluent. Therefore, WWTPs based on activated sludge used in sewage treatment constitute an important reservoir of enteric bacteria which harbour potentially transferable resistance genes. Together with treated wastewater, these microorganisms can penetrate the soil, surface water, rural groundwater supplies and drinking water. Because of this, the aim of this study was to determine the impact of various modification of sewage treatment (the conventional anaerobic/anoxic/oxic (A2/O) process, mechanical-biological (MB) system, sequencing batch reactors (SBR), mechanical-biological system with elevated removal of nutrients (MB-ERN)) on the amount of antibiotic resistant bacteria (ARB) (including E . coli ) and antibiotic resistance genes (ARGs) in sewage flowing out of the 13 treatment plants using activated sludge technology. There were no significant differences in ARB and ARGs regardless of time of sampling and type of treated wastewater ( p  > 0.05). The highest percentage of reduction (up to 99.9%) in the amount of ARB and ARGs was observed in WWTPs with MB and MB-ERN systems. The lowest reduction was detected in WWTPs with SBR. A significant increase ( p  < 0.05) in the percentage of bacteria resistant to the new generation antibiotics (CTX and DOX) in total counts of microorganisms was observed in effluents (EFF) from WWTPs with A2/O system and with SBR. Among all ARGs analyzed, the highest prevalence of ARGs copies in EFF samples was observed for sul 1, tet (A) and qep A, the lowest for bla TEM and bla SHV . Although, the results of presented study demonstrate high efficiency of ARB and ARGs removal during the wastewater treatment processes, especially by WWTPs with MB and MB-ERN systems, EFF is still an important reservoir of ARGs which can be transferred to other microorganisms. [ABSTRACT FROM AUTHOR]

Shrimp ( Litopenaeus vannamei ) farming is an important economic activity in several countries. Pathogens in shrimp farms and its effluents pose a potential hazard for both humans and shrimps. Wild strains of bacteria were characterized in a shrimp farm, and Klebsiella pneumoniae was chosen as a good indicator due to its presence in the pond and the effluent and its resistance to antibiotics. Different photochemical processes (UV/H 2 O 2 , UV/H 2 O 2 /Fe 3+ ) were tested for inactivation of wild isolated K. pneumoniae and compared to UV-C radiation. By kinetic modelling, a k max equal to 0.43 s −1 was obtained for UV-C treatment. After optimizing the cited processes, ranging [H 2 O 2 ]: 10–30 mg·l −1 ; an optimal [H 2 O 2 ] of 10 mg·l −1 was found, increasing k max on 13.63% compared to UV-C. This optimal concentration was tested for UV/H 2 O 2 /Fe 3+ process; ranging [Fe 3+ ]: 2–20 mg·l −1 . The highest yield was obtained by a [H 2 O 2 ]:[Fe 3+ ] = 10:2, which leads to 4-Log reduction in 12.88 s of treatment. Moreover, resistance of K. pneumoniae was compared to Escherichia coli. The latter proved to be more sensitive despite its similar cellular structure. Results suggested that the photochemical processes could enhance disinfection efficiency, especially for photo-assisted Fenton-like process in most resistant bacteria. [ABSTRACT FROM AUTHOR]

Around 350 million tons of solid waste is disposed of in landfills every year globally, with millions of cubic meters of landfill leachates released into neighboring environment. However, to date, little is known about the variations of antimicrobial resistance (AMR) in on-site leachate treatment systems and its development in leachate-receiving water environment. Here, we quantified 7 subtypes of antibiotic resistance genes (ARGs), 3 types of culturable antibiotic resistant bacteria (ARB) and 6 subtypes of mobile genetic elements (MGEs) in the effluents from a combined leachate treatment process, including biological treatment (MBR), physical separation (UF), ultraviolet (UV) disinfection and advanced oxidation process (AOP). The contents of ARGs, ARB and MGEs were generally enriched by the MBR, but then decreased significantly along with the tertiary treatment process. However, in the effluent-receiving water samples, the abundance of dominant ARGs (i.e. ermB , sul1 , bla TEM ) increased by 1.5 orders of magnitude within 96 h, alongside a general increase of MGEs (~10.0 log 10 (copies/mL) and total ARB (~1100 CFU/mL). Structural correlation analyses reveal that target ARGs were closely associated with MGEs, particularly in effluent-receiving samples (Procrustes test; M 2  = 0.49, R  = 0.71, P  = 0.001); and occurrences of ARB were majorly affected by ARG's distribution and environmental conditions (e.g. nitrogen speciation) in effluent and recipient groups, respectively. This study indicates that current treatment technologies and operation protocols are not feasible in countering the development of AMR in effluent-receiving water environment, particularly in tidal rivers that are capable of retaining contaminants for a long residence time. [ABSTRACT FROM AUTHOR]

Objective: To determine and identify antibiotic-resistant bacteria (ARB) of oral streptococci from active dental infections in adults and its association with age and gender.Material and Methods: This cross-sectional study included 59 subjects from 18 to 62 years old. Ninety-eighth samples obtained from the subjects were cultivated in agar plates containing antibiotics amoxicillin/clavulanic acid (A-CA), clindamycin, and moxifloxacin (concentrations of 16, 32 or 64 µg/ml). PCR assay was performed to identify bacterial species.Results: The bacterial species that showed more antibiotic-resistance (AR) was S. mutans (45.9%), followed by S. gordonii (21.6%), S. oralis (17.6%), S. sanguinis (9.5%), S. salivarius (5.4%) and S. sobrinus (0%). Moreover, clindamycin (59.4%) showed the highest frequency of AR. Moxifloxacin and A-CA showed an susceptibility >99.1%, while clindamycin showed the lowest efficacy (93.3%); there was a significant statistically difference (p < .01). The age group between 26 and 50 years old (32.2%) and females (28.8%) showed more multiresistance. Clindamycin showed a statistical difference (p < .05) when comparing groups by gender.Conclusions: Clindamycin was the antibiotic with the highest frequency of ARB and lower bactericidal effect. Moxifloxacin and A-CA showed the highest efficacy and the lowest ARB frequency. Streptococcus mutans was the bacterial specie that showed an increased frequency of AR. [ABSTRACT FROM AUTHOR]

The emerging mixed contamination of antibiotics and microplastics in greenhouse soil has made the control of antibiotic resistant gene (ARG) transmission a novel challenge. In this work, surfactant sophorolipid was applied to enhance the dissipation of tetracycline (TC) and tet genes in the presence of microplastics in greenhouse soil. During 49 days of incubation, soil bacteria and phages were both found to be the crucial reservoirs of ARGs. Meanwhile, microplastic’s presence significantly inhibited the dissipation of TC and ARGs in the soil. However, sophorolipid application was proved to outweigh the negative impact caused by microplastic existence, and lead to the highest dissipation of soil TC and ARGs. Significant positive correlation was detected between the dissipation rate of water-soluble and exchangeable TC content and bacteria/phage co-mediated ARG levels. This also held true between the two fractions of soil TC and the ratio of ARG level in the bacteria to that in the phages (B ARGs /P ARGs ). The opposite impacts of microplastic presence and sophorolipid amendment on the TC/ARG dissipation found in this work provides new information for understanding ARG transmission between bacteria and phages in the mixed contaminated greenhouse soil. [ABSTRACT FROM AUTHOR]

Antibiotic resistance in drinking water has received increasing attention in recent years. In this study, the occurrence and abundance of antibiotic resistance genes (ARGs) in a drinking water treatment plant (DWTP) was comprehensively investigated using metagenomics. Bioinformatics analysis showed that 381 ARG subtypes belonging to 15 ARG types were detected, and bacitracin had the highest abundance (from 0.26 × 10−2 to 0.86 copies/cell), followed by multidrug (from 0.57 × 10−1 to 0.47 copies/cell) and sulfonamide (from 0.83 × 10−2 to 0.35 copies/cell). Additionally, 933 ARG-carrying contigs (ACCs) were obtained from the metagenomic data, among which 153 contigs were annotated as pathogens. The most abundant putative ARG host was Staphylococcus (7.9%), which most frequently carried multidrug ARGs (43.2%). Additionally, 38 high-quality metagenome-assembled genomes (MAGs) were recovered, one of which was identified as Staphylococcus aureus (Bin.624) and harboured the largest number of ARGs (n = 16). Using the cultivation technique, 60 isolates were obtained from DWTP samples, and Staphylococcus spp. (n = 11) were found to be dominant in all isolates, followed by Bacillus spp. (n = 17). Antimicrobial susceptibility testing showed that most Staphylococcus spp. were multidrug resistant (MDR). These results deepen our understanding of the distribution profiles of ARGs and antibiotic resistant bacteria (ARB) in DWTPs for potential health risk evaluation. Our study also highlights the need for new and efficient water purification technologies that can be introduced and applied in DWTPs. • Bacitracin, multidrug and sulfonamide resistance genes were dominant in DWTP. • Staphylococcus was the most abundant putative ARG host in the DWTP. • 50% of the selected isolates were multidrug resistant. [ABSTRACT FROM AUTHOR]

In the past few decades, infectious diseases have become increasingly challenging to treat, which is explained by the growing number of antibiotic-resistant bacteria. Notably, carbapenem-resistant Enterobacteriaceae (CRE) infections at global level attribute a vast, dangerous clinical threat. In most cases, there are enormous difficulties for CRE infection except a few last resort toxic drugs such as tigecycline and colistin (polymyxin E). Due to this, CRE has now been categorized as one among the three most dangerous multidrug resistance (MDR) pathogens by the US Centres for Disease Control and Prevention (CDC). Considering this, the study of the frequency of CRE infections and the characterization of CRE is an important area of research in clinical settings. However, MDR bacteria are not only present in hospitals but are spreading more and more into the environment, thereby increasing the risk of infection with resistant bacteria outside the hospital. In this context, developing countries are a global concern where environmental regulations are often insufficient. It seems likely that overcrowding, poor sanitation, socioeconomic status, and limited infrastructures contribute to the rapid spread of MDR bacteria, becoming their reservoirs in the environment. Thus, in this review, we present the occurrence of CRE and their resistance determinants in different environmental compartments in India.