Existing evidence on antibiotic resistance exposure and transmission to humans from the environment: a systematic map

Characterisation of microbial communities and quantification of antibiotic resistance genes in Italian wastewater treatment plants using 16S rRNA sequencing and digital PCR

The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in humans, animals and environment is a growing threat to public health. Wastewater treatment plants (WWTPs) are crucial in mitigating the risk of environmental contamination by effectively removing contaminants before discharge. However, the persistence of ARB and ARGs even after treatment is a challenge for the management of water system. To comprehensively assess antimicrobial resistance dynamics, we conducted a one-year monitoring study in three WWTPs in central Italy, both influents and effluents. We used seasonal sampling to analyze microbial communities by 16S rRNA, as well as to determine the prevalence and behaviour of major ARGs (sul1, tetA, blaTEM, blaOXA-48, blaCTX-M-1 group, blaKPC) and the class 1 Integron (int1). Predominant genera included in order: Arcobacter, Acinetobacter, Flavobacterium, Pseudarcobacter, Bacteroides, Aeromonas, Trichococcus, Cloacibacterium, Pseudomonas and Streptococcus. A higher diversity of bacterial communities was observed in the effluents compared to the influents. Within these communities, we also identified bacteria that may be associated with antibiotic resistance and pose a significant threat to human health. The mean concentrations (in gene copies per liter, gc/L) of ARGs and int1 in untreated wastewater (absolute abundance) were as follows: sul1 (4.1 × 109), tetA (5.2 × 108), blaTEM (1.1 × 108), blaOXA-48 (2.1 × 107), blaCTX-M-1 group (1.1 × 107), blaKPC (9.4 × 105), and int1 (5.5 × 109). The mean values in treated effluents showed reductions ranging from one to three log. However, after normalizing to the 16S rRNA gene (relative abundance), it was observed that in 37.5 % (42/112) of measurements, the relative abundance of ARGs increased in effluents compared to influents. Furthermore, correlations were identified between ARGs and bacterial genera including priority pathogens. This study improves our understanding of the dynamics of ARGs and provides insights to develop more effective strategies to reduce their spread, protecting public health and preserving the future efficacy of antibiotics.

Effects of hydrothermal treatment on the reduction of antibiotic-resistant Escherichia coli and antibiotic resistance genes and the fertilizer potential of liquid product from cattle manure

In this study, the reduction in the abundance of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) and the fertilizer potential of liquid products from hydrothermally treated cattle manure were investigated. Hydrothermal treatment (HTT) was conducted under different reaction temperatures (125, 150, 175 and 200 °C) and retention times (60, 90 and 120 min). The total organic carbon (TOC) and total nitrogen (TN) of the liquid product increased with increasing reaction temperature. The germination index (GI), a measure of the percentage of germination, exceeded 90 % at 125, 150, and 175 °C in diluted samples, while it decreased to 18 % at 200 °C. Although a longer retention time contributed to an increase in TOC of liquid products, it did not increase the GI values. The liquid product should be diluted or adjusted before use as fertilizer to prevent phytotoxicity. In our analysis of ARB and ARGs, E. coli and antibiotic-resistant E. coli were completely reduced after HTT, except for the operating conditions of 125 °C and 60 min. Although both a higher reaction temperature and longer retention time tended to be better for the reduction of ARGs and intI1, it was found that the longer retention time is much more effective than the higher reaction temperature. The reduction of target ARGs and intI1 was 2.9-log under175 °C and 120 min. Comprehensively considering the fertilizer potential of liquid product and the reduction of ARB and ARGs, 175 °C of reaction temperature and 120 min of retention time of operating conditions for HTT were recommended.

Do storm overflows influence AMR in the environment and is this relevant to human health? A UK perspective on a global issue

Antimicrobial resistance (AMR) is a global public health threat, and the environment has been identified as an important reservoir for resistant microorganisms and genes. Storm overflows (SOs) discharge wastewater and stormwater, and are found throughout many wastewater networks. While there are no data currently showing the impact of SOs on the environment with respect to AMR in the UK, there is a small but growing body of evidence globally highlighting the potential role of SOs on environmental AMR. This review aims to provide an overview of the current state of SOs, describe global data investigating the impact of SOs on environmental AMR, and discuss the implications of SOs regarding AMR and human health. In addition, the complexities of studying the effects of SOs are discussed and a set of priority research questions and policy interventions to tackle a potentially emerging threat to public health are presented.

Recent development and fighting strategies for lincosamide antibiotic resistance

SUMMARYLincosamides constitute an important class of antibiotics used against a wide range of pathogens, including methicillin-resistant Staphylococcus aureus. However, due to the misuse of lincosamide and co-selection pressure, the resistance to lincosamide has become a serious concern. It is urgently needed to carefully understand the phenomenon and mechanism of lincosamide resistance to effectively prevent and control lincosamide resistance. To date, six mobile lincosamide resistance classes, including lnu, cfr, erm, vga, lsa, and sal, have been identified. These lincosamide resistance genes are frequently found on mobile genetic elements (MGEs), such as plasmids, transposons, integrative and conjugative elements, genomic islands, and prophages. Additionally, MGEs harbor the genes that confer resistance not only to antimicrobial agents of other classes but also to metals and biocides. The ultimate purpose of discovering and summarizing bacterial resistance is to prevent, control, and combat resistance effectively. This review highlights four promising strategies, including chemical modification of antibiotics, the development of antimicrobial peptides, the initiation of bacterial self-destruct program, and antimicrobial stewardship, to fight against resistance and safeguard global health.

A one health approach for monitoring antimicrobial resistance: developing a national freshwater pilot effort

Antimicrobial resistance (AMR) is a world-wide public health threat that is projected to lead to 10 million annual deaths globally by 2050. The AMR public health issue has led to the development of action plans to combat AMR, including improved antimicrobial stewardship, development of new antimicrobials, and advanced monitoring. The National Antimicrobial Resistance Monitoring System (NARMS) led by the United States (U.S) Food and Drug Administration along with the U.S. Centers for Disease Control and U.S. Department of Agriculture has monitored antimicrobial resistant bacteria in retail meats, humans, and food animals since the mid 1990's. NARMS is currently exploring an integrated One Health monitoring model recognizing that human, animal, plant, and environmental systems are linked to public health. Since 2020, the U.S. Environmental Protection Agency has led an interagency NARMS environmental working group (EWG) to implement a surface water AMR monitoring program (SWAM) at watershed and national scales. The NARMS EWG divided the development of the environmental monitoring effort into five areas: (i) defining objectives and questions, (ii) designing study/sampling design, (iii) selecting AMR indicators, (iv) establishing analytical methods, and (v) developing data management/analytics/metadata plans. For each of these areas, the consensus among the scientific community and literature was reviewed and carefully considered prior to the development of this environmental monitoring program. The data produced from the SWAM effort will help develop robust surface water monitoring programs with the goal of assessing public health risks associated with AMR pathogens in surface water (e.g., recreational water exposures), provide a comprehensive picture of how resistant strains are related spatially and temporally within a watershed, and help assess how anthropogenic drivers and intervention strategies impact the transmission of AMR within human, animal, and environmental systems.

Genomic analysis of Salmonella isolated from canal water in Bangkok, Thailand

Antimicrobial resistance (AMR) poses an escalating global public health threat. Canals are essential in Thailand, including the capital city, Bangkok, as agricultural and daily water sources. However, the characteristic and antimicrobial-resistance properties of the bacteria in the urban canals have never been elucidated. This study employed whole genome sequencing to characterize 30 genomes of a causal pathogenic bacteria, Salmonella enterica, isolated from Bangkok canal water between 2016 and 2020. The dominant serotype was Salmonella Agona. In total, 35 AMR genes and 30 chromosomal-mediated gene mutations were identified, in which 21 strains carried both acquired genes and mutations associated with fluoroquinolone resistance. Virulence factors associated with invasion, adhesion, and survival during infection were detected in all study strains. 75.9% of the study stains were multidrug-resistant and all the strains harbored the necessary virulence factors associated with salmonellosis. One strain carried 20 resistance genes, including mcr-3.1, mutations in GyrA, ParC, and ParE, and typhoid toxin-associated genes. Fifteen plasmid replicon types were detected, with Col(pHAD28) being the most common type. Comparative analysis of nine S. Agona from Bangkok and 167 from public databases revealed that specific clonal lineages of S. Agona might have been circulating between canal water and food sources in Thailand and globally. These findings provide insight into potential pathogens in the aquatic ecosystem and support the inclusion of environmental samples into comprehensive AMR surveillance initiatives as part of a One Health approach. This approach aids in comprehending the rise and dissemination of AMR and devising sustainable intervention strategies.IMPORTANCEBangkok is the capital city of Thailand and home to a large canal network that serves the city in various ways. The presence of pathogenic and antimicrobial-resistant Salmonella is alarming and poses a significant public health risk. The present study is the first characterization of the genomic of Salmonella strains from Bangkok canal water. Twenty-two of 29 strains (75.9%) were multidrug-resistant Salmonella and all the strains carried essential virulence factors for pathogenesis. Various plasmid types were identified in these strains, potentially facilitating the horizontal transfer of AMR genes. Additional investigations indicated a potential circulation of S. Agona between canal water and food sources in Thailand. The current study underscores the role of environmental water in an urban city as a reservoir of pathogens and these data obtained can serve as a basis for public health risk assessment and help shape intervention strategies to combat AMR challenges in Thailand.

Leveraging genomic signatures of oral microbiome-associated antibiotic resistance genes for diagnosing pancreatic cancer

Growing evidence has increasingly suggested a potential linkage between the oral microbiome and various diseases, including pancreatic ductal adenocarcinoma (PDAC). However, the utilization of gene-level information derived from the oral microbiome for diagnosing PDAC remains unexplored. In this study, we sought to investigate the novel potential of leveraging genomic signatures associated with antibiotic resistance genes (ARGs) within the oral microbiome for the diagnosis of PDAC. By conducting an analysis of oral microbiome samples obtained from PDAC patients, we successfully identified specific ARGs that displayed distinct sequence abundance profiles correlated with the presence of PDAC. In the healthy group, three ARGs were found to be enriched, whereas 21 ARGs were enriched in PDAC patients. Remarkably, these ARGs from oral microbiome exhibited promising diagnostic capabilities for PDAC (AUROC = 0.79), providing a non-invasive and early detection method. Our findings not only provide novel modal data for diagnosing PDAC but also shed light on the intricate interplay between the oral microbiome and PDAC.

Weissella sp. SNUL2 as potential probiotics with broad-spectrum antimicrobial activities

Probiotics have been applied to a wide range of bacteria, causing gastrointestinal and vaginal infections. However, probiotics generally possess limited antimicrobial spectra and are primarily utilized as dietary supplements. Recognizing the need for more versatile probiotics, this study focuses on isolating and characterizing strains suitable for antibiotic replacement. Among these strains, Weissella sp. SNUL2, derived from a traditional fermented food in Korea (i.e., Sikhae), emerged as a promising candidate. The correlation between optical density at 600 nm and colony-forming units was verified and applied in subsequent experiments. To assess the therapeutic potential of probiotics, antibacterial tests were conducted using a microplate reader to evaluate the inhibition of 60 bacterial strains (including common foodborne pathogens) induced by Weissella sp. SNUL2 cell-free supernatant (CFS). The results confirmed its broad-spectrum antibacterial properties compared to previously known probiotics. Furthermore, enzymatic treatment with proteinases (trypsin and pepsin) and a time-kill assay were conducted to elucidate the nature of the antibacterial substance in Weissella sp. SNUL2 CFS. Through sequential chromatography involving gel filtration and ion-exchange chromatography, specific fractions with enhanced antibacterial properties were identified. LC-MS/MS analysis of the secretome fraction revealed the presence of various proteins from the C39 family, peptidoglycan endopeptidases, and N-acetylmuramoyl-l-alanine amidase domain-containing protein precursors. Hence, the combined action of these proteins may contribute to Weissella sp. SNUL2's broad antimicrobial activity.

Protecting the Last Line of Defense: Analytical Approaches for Sample Preparation and Determination of the Reserve Group of Antibiotics in the Environment

Drug resistance in microorganisms is a serious threat to life and health due to the limited number of antibiotics that show efficacy in treating infections and the difficulty in discovering new compounds with antibacterial activity. To address this issue, the World Health Organization created the AWaRe classification, a tool to support global and national antimicrobial stewardship programs. The AWaRe list categorizes antimicrobials into three groups - Access, Watch, and Reserve - according to their intended use. The Reserve group comprises "last resort" medicines used solely for treating infections caused by bacterial strains that are resistant to other treatments. It is therefore necessary to protect them, not only by using them as prudently as possible in humans and animals, but also by monitoring their subsequent fate. Unmetabolized antibiotics enter the environment through hospital and municipal wastewater or from manure, subsequently contaminating bodies of water and soils, thus contributing to the emergence and spread of antibiotic resistance. This article presents a review of determination methods for the Reserve group of antimicrobials in water, wastewater, and manure. Procedures for extracting and determining these substances in environmental samples are described, showing the limited research available, which is typically on a local level.

Linking antibiotic resistance gene patterns with advanced faecal pollution assessment and environmental key parameters along 2300 km of the Danube River

The global spread of antimicrobial resistance (AMR) in the environment is a growing health threat. Large rivers are of particular concern as they are highly impacted by wastewater discharge while being vital lifelines serving various human needs. A comprehensive understanding of occurrence, spread and key drivers of AMR along whole river courses is largely lacking. We provide a holistic approach by studying spatiotemporal patterns and hotspots of antibiotic resistance genes (ARGs) along 2311 km of the navigable Danube River, combining a longitudinal and temporal monitoring campaign. The integration of advanced faecal pollution diagnostics and environmental and chemical key parameters allowed linking ARG concentrations to the major pollution sources and explaining the observed patterns. Nine AMR markers, including genes conferring resistance to five different antibiotic classes of clinical and environmental relevance, and one integrase gene were determined by probe-based qPCR. All AMR targets could be quantified in Danube River water, with intI1 and sul1 being ubiquitously abundant, qnrS, tetM, blaTEM with intermediate abundance and blaOXA-48like, blaCTX-M-1 group, blaCTX-M-9 group and blaKPC genes with rare occurrence. Human faecal pollution from municipal wastewater discharges was the dominant factor shaping ARG patterns along the Danube River. Other significant correlations of specific ARGs were observed with discharge, certain metals and pesticides. In contrast, intI1 was not associated with wastewater but was already established in the water microbiome. Animal contamination was detected only sporadically and was correlated with ARGs only in the temporal sampling set. During temporal monitoring, an extraordinary hotspot was identified emphasizing the variability within natural waters. This study provides the first comprehensive baseline concentrations of ARGs in the Danube River and lays the foundation for monitoring future trends and evaluating potential reduction measures. The applided holistic approach proved to be a valuable methodological contribution towards a better understanding of the environmental occurrence of AMR.

Characterising proximal and distal drivers of antimicrobial resistance: An umbrella review

INTRODUCTION

Antimicrobial resistance (AMR) is a multifactorial challenge driven by a complex interplay of proximal drivers, such as the overuse and misuse of antimicrobials and the high burden of infectious diseases, and distal factors, encompassing broader societal conditions such as poverty, inadequate sanitation, and healthcare system deficiencies. However, distinguishing between proximal and distal drivers remains a conceptual challenge.

OBJECTIVES

We conducted an umbrella review, aiming to systematically map current evidence about proximal and distal drivers of AMR and to investigate their relationships.

METHODS

Forty-seven reviews were analysed, and unique causal links were retained to construct a causality network of AMR. To distinguish between proximal and distal drivers, we calculated a 'driver distalness index (Di)', defined as an average relative position of a driver in its causal pathways to AMR.

RESULTS

The primary emphasis of the literature remained on proximal drivers, with fragmented existing evidence about distal drivers. The network analysis showed that proximal drivers of AMR are associated with risks of resistance transmission (Di = 0.49, SD = 0.14) and antibiotic use (Di = 0.58, SD = 0.2), which are worsened by intermediate drivers linked with challenges of antibiotic discovery (Di = 0.62, SD = 0.07), infection prevention (Di = 0.67, SD = 0.14) and surveillance (Di = 0.69, SD = 0.16). Distal drivers, such as living conditions, access to sanitation infrastructure, population growth and urbanisation, and gaps in policy implementation were development and governance challenges, acting as deep leverage points in the system in addressing AMR.

CONCLUSIONS

Comprehensive AMR strategies aiming to address multiple chronic AMR challenges must take advantage of opportunities for upstream interventions that specifically address distal drivers.

Does Environmental Exposure to Pharmaceutical and Personal Care Product Residues Result in the Selection of Antimicrobial-Resistant Microorganisms, and is this Important in Terms of Human Health Outcomes?

The environment plays a critical role in the development, dissemination, and transmission of antimicrobial resistance (AMR). Pharmaceuticals and personal care products (PPCPs) enter the environment through direct application to the environment and through anthropogenic pollution. Although there is a growing body of evidence defining minimal selective concentrations (MSCs) of antibiotics and the role antibiotics play in horizontal gene transfer (HGT), there is limited evidence on the role of non-antibiotic PPCPs. Existing data show associations with the development of resistance or effects on bacterial growth rather than calculating selective endpoints. Research has focused on laboratory-based systems rather than in situ experiments, although PPCP concentrations found throughout wastewater, natural water, and soil environments are often within the range of laboratory-derived MSCs and at concentrations shown to promote HGT. Increased selection and HGT of AMR by PPCPs will result in an increase in total AMR abundance in the environment, increasing the risk of exposure and potential transmission of environmental AMR to humans. There is some evidence to suggest that humans can acquire resistance from environmental settings, with water environments being the most frequently studied. However, because this is currently limited, we recommend that more evidence be gathered to understand the risk the environment plays in regard to human health. In addition, we recommend that future research efforts focus on MSC-based experiments for non-antibiotic PPCPS, particularly in situ, and investigate the effect of PPCP mixtures on AMR. Environ Toxicol Chem 2024;43:623-636. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

The Complex Interplay Between Antibiotic Resistance and Pharmaceutical and Personal Care Products in the Environment

Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are important environmental contaminants. Nonetheless, what drives the evolution, spread, and transmission of antibiotic resistance dissemination is still poorly understood. The abundance of ARB and ARGs is often elevated in human-impacted areas, especially in environments receiving fecal wastes, or in the presence of complex mixtures of chemical contaminants, such as pharmaceuticals and personal care products. Self-replication, mutation, horizontal gene transfer, and adaptation to different environmental conditions contribute to the persistence and proliferation of ARB in habitats under strong anthropogenic influence. Our review discusses the interplay between chemical contaminants and ARB and their respective genes, specifically in reference to co-occurrence, potential biostimulation, and selective pressure effects, and gives an overview of mitigation by existing man-made and natural barriers. Evidence and strategies to improve the assessment of human health risks due to environmental antibiotic resistance are also discussed. Environ Toxicol Chem 2024;43:637-652. © 2022 SETAC.

Examining Antimicrobial Resistance in Escherichia coli: A Case Study in Central Virginia's Environment

While environmental factors may contribute to antimicrobial resistance (AMR) in bacteria, many aspects of environmental antibiotic pollution and resistance remain unknown. Furthermore, the level of AMR in Escherichia coli is considered a reliable indicator of the selection pressure exerted by antimicrobial use in the environment. This study aimed to assess AMR variance in E. coli isolated from diverse environmental samples, such as animal feces and water from wastewater treatment plants (WWTPs) and drainage areas of different land use systems in Central Virginia. In total, 450 E. coli isolates obtained between August 2020 and February 2021 were subjected to susceptibility testing against 12 antimicrobial agents approved for clinical use by the U.S. Food and Drug Administration. Approximately 87.8% of the tested isolates were resistant to at least one antimicrobial agent, with 3.1% showing multi-drug resistance. Streptomycin resistance was the most common (73.1%), while susceptibility to chloramphenicol was the highest (97.6%). One isolate obtained from WWTPs exhibited resistance to seven antimicrobials. AMR prevalence was the highest in WWTP isolates, followed by isolates from drainage areas, wild avians, and livestock. Among livestock, horses had the highest AMR prevalence, while cattle had the lowest. No significant AMR difference was found across land use systems. This study identifies potential AMR hotspots, emphasizing the environmental risk for antimicrobial resistant E. coli. The findings will aid policymakers and researchers, highlighting knowledge gaps in AMR-environment links. This nationally relevant research offers a scalable AMR model for understanding E. coli ecology. Further large-scale research is crucial to confirm the environmental impacts on AMR prevalence in bacteria.

Longitudinal carriage of antimicrobial resistant Enterobacterales in healthy individuals in Ireland - Assessing the impact of recreational water use on duration of carriage

The increasing prevalence of extended-spectrum beta-lactamase (ESBL) producing Enterobacterales (ESBL-PE) and carbapenemase-producing Enterobacterales (CPE) is a major public health concern worldwide. Despite the associated risk of infection from gut colonisation with a resistant Enterobacterales, the incidence and duration of carriage in healthy individuals is poorly studied. This "persistence study" is the first in Ireland to assess the longitudinal carriage of ESBL-PE and CPE in healthy individuals. A cohort of 45 participants, 22 of whom were colonised with ESBL-PE, was recruited from a recently completed point prevalence study that investigated colonisation in recreational water users (WU) versus controls. Six bi-monthly faecal samples per participant were analysed for CPE and ESBL-PE over one year and the relationship between persistent colonisation and exposure to natural waters was investigated. For 11 of 45 participants (24.4 %) ESBL-E. coli (ESBL-EC) was detected in at least one sample. Genomic analysis revealed that six participants harboured the same ESBL-EC strains as identified in the preceding study. ESBL-EC persisted in the gut for a median duration of 10.3 months (range 4-23 months), consistent with previous research. Five participants (11.1 %) carried ESBL-EC for the entire study year. The carbapenemase gene blaIMI-2 was detected once. Colonisation was higher in water users during the non-bathing season (n = 10, November 2021-April 2022), than during the bathing season (n = 5, May 2022-September 2022) [relative risk 1.99 (95 % CI 0.34-11.71)]. However, overall WU were less likely to be colonised with ESBL-EC than controls (19 % vs 25 % respectively, RR 0.76, CI 0.24-2.34). Further research is warranted to better understand the factors influencing the persistence of gut colonisation with ESBL-EC and CPE and to what extent bathing water quality impacts colonisation for those regularly exposed.

Potential Causes of Spread of Antimicrobial Resistance and Preventive Measures in One Health Perspective-A Review

Antimicrobial resistance, referring to microorganisms' capability to subsist and proliferate even when there are antimicrobials is a foremost threat to public health globally. The appearance of antimicrobial resistance can be ascribed to anthropological, animal, and environmental factors. Human-related causes include antimicrobial overuse and misuse in medicine, antibiotic-containing cosmetics and biocides utilization, and inadequate sanitation and hygiene in public settings. Prophylactic and therapeutic antimicrobial misuse and overuse, using antimicrobials as feed additives, microbes resistant to antibiotics and resistance genes in animal excreta, and antimicrobial residue found in animal-origin food and excreta are animals related contributive factors for the antibiotic resistance emergence and spread. Environmental factors including naturally existing resistance genes, improper disposal of unused antimicrobials, contamination from waste in public settings, animal farms, and pharmaceutical industries, and the use of agricultural and sanitation chemicals facilitatet its emergence and spread. Wildlife has a plausible role in the antimicrobial resistance spread. Adopting a one-health approach involving using antimicrobials properly in animals and humans, improving sanitation in public spaces and farms, and implementing coordinated governmental regulations is crucial for combating antimicrobial resistance. Collaborative and cooperative involvement of stakeholders in public, veterinary and ecological health sectors is foremost to circumvent the problem effectively.

One Health Determinants of Escherichia coli Antimicrobial Resistance in Humans in the Community: An Umbrella Review

To date, the scientific literature on health variables for Escherichia coli antimicrobial resistance (AMR) has been investigated throughout several systematic reviews, often with a focus on only one aspect of the One Health variables: human, animal, or environment. The aim of this umbrella review is to conduct a systematic synthesis of existing evidence on Escherichia coli AMR in humans in the community from a One Health perspective. PubMed, EMBASE, and CINAHL were searched on "antibiotic resistance" and "systematic review" from inception until 25 March 2022 (PROSPERO: CRD42022316431). The methodological quality was assessed, and the importance of identified variables was tabulated across all included reviews. Twenty-three reviews were included in this study, covering 860 primary studies. All reviews were of (critically) low quality. Most reviews focused on humans (20), 3 on animals, and 1 on both human and environmental variables. Antibiotic use, urinary tract infections, diabetes, and international travel were identified as the most important human variables. Poultry farms and swimming in freshwater were identified as potential sources for AMR transmission from the animal and environmental perspectives. This umbrella review highlights a gap in high-quality literature investigating the time between variable exposure, AMR testing, and animal and environmental AMR variables.

Antimicrobial Resistance in Bacteria from Meat and Meat Products: A One Health Perspective

According to the 2030 Agenda of the United Nations, one of the sustainable development goals is to ensure sustainable consumption and production patterns. The need to ensure food safety includes, other than microbiological hazards, concerns with antimicrobial-resistant (AMR) bacteria. The emergence of resistant bacteria in the food industry is essentially due to the abusive, and sometimes incorrect, administration of antimicrobials. Although not allowed in Europe, antimicrobials are often administered to promote animal growth. Each time antimicrobials are used, a selective pressure is applied to AMR bacteria. Moreover, AMR genes can be transmitted to humans through the consumption of meat-harbouring-resistant bacteria, which highlights the One Health dimension of antimicrobial resistance. Furthermore, the appropriate use of antimicrobials to ensure efficacy and the best possible outcome for the treatment of infections is regulated through the recommendations of antimicrobial stewardship. The present manuscript aims to give the current state of the art about the transmission of AMR bacteria, particularly methicillin-resistant S. aureus, ESBL-producing Enterobacteriaceae, and vancomycin-resistant Enterococcus spp., along with other ESKAPE bacteria, from animals to humans through the consumption of meat and meat products, with emphasis on pork meat and pork meat products, which are considered the most consumed worldwide.

Outpatient management of urinary tract infections by medical officers in Nairobi, Kenya: lack of benefit from audit and feedback on adherence to treatment guidelines

INTRODUCTION

Acute uncomplicated urinary tract infections are common in outpatient settings but are not treated optimally. Few studies of the outpatient use of antibiotics for specific diagnoses have been done in sub-Saharan Africa, so little is known about the prescribing patterns of medical officers in the region.

METHODS

Aga Khan University has 16 outpatient clinics throughout the Nairobi metro area with a medical officer specifically assigned to that clinic. A baseline assessment of evaluation and treatment of suspected UTI was performed from medical records in these clinics. Then the medical officer from each of the 16 clinics was recruited from each clinic was recruited with eight each randomized to control vs. feedback groups. Both groups were given a multimodal educational session including locally adapted UTI guidelines and emphasis on problems identified in the baseline assessment Each record was scored using a scoring system that was developed for the study according to adequacy of history, physical examination, clinical diagnosis matching recorded data, diagnostic workup and treatment. Three audits were done for both groups; baseline (audit 1), post-CME (audit 2), and a final audit, which was after feedback for the feedback group (audit 3). The primary analysis assessed overall guideline adherence in the feedback group versus the CME only group.

RESULTS

The overall scores in both groups showed significant improvement after the CME in comparison to baseline and for each group, the scores in most domains also improved. However, audit 3 showed persistence of the gains attained after the CME but no additional benefit from the feedback. Some deficiencies that persisted throughout the study included lack of workup of possible STI and excess use of non-UTI laboratory tests such as CBC, stool culture and H. pylori Ag. After the CME, the use of nitrofurantoin rose from only 4% to 8% and cephalosporin use increased from 49 to 67%, accompanied by a drop in quinolone use.

CONCLUSION

The CME led to modest improvements in patient care in the categories of history taking, treatment and investigations, but feedback had no additional effect. Future studies should consider an enforcement element or a more intensive feedback approach.

Towards monitoring of antimicrobial resistance in the environment: For what reasons, how to implement it, and what are the data needs?

Antimicrobial resistance (AMR) is a global threat to human and animal health and well-being. To understand AMR dynamics, it is important to monitor resistant bacteria and resistance genes in all relevant settings. However, while monitoring of AMR has been implemented in clinical and veterinary settings, comprehensive monitoring of AMR in the environment is almost completely lacking. Yet, the environmental dimension of AMR is critical for understanding the dissemination routes and selection of resistant microorganisms, as well as the human health risks related to environmental AMR. Here, we outline important knowledge gaps that impede implementation of environmental AMR monitoring. These include lack of knowledge of the 'normal' background levels of environmental AMR, definition of high-risk environments for transmission, and a poor understanding of the concentrations of antibiotics and other chemical agents that promote resistance selection. Furthermore, there is a lack of methods to detect resistance genes that are not already circulating among pathogens. We conclude that these knowledge gaps need to be addressed before routine monitoring for AMR in the environment can be implemented on a large scale. Yet, AMR monitoring data bridging different sectors is needed in order to fill these knowledge gaps, which means that some level of national, regional and global AMR surveillance in the environment must happen even without all scientific questions answered. With the possibilities opened up by rapidly advancing technologies, it is time to fill these knowledge gaps. Doing so will allow for specific actions against environmental AMR development and spread to pathogens and thereby safeguard the health and wellbeing of humans and animals.

Multichannel Microfluidic Platform for Temporal-Spatial Investigation of Niche Roles of Pseudomonas aeruginosa and Escherichia coli within a Dual-Species Biofilm

In natural or man-made environments, microorganisms exist predominantly as biofilms forming surface-associated bacterial communities embedded in extracellular polymeric substances (EPSs). Often, biofilm reactors used for endpoint and disruptive analyses of biofilm are not suitable for periodic observation of biofilm formation and development. In this study, a microfluidic device designed with multiple channels and a gradient generator was used for high-throughput analysis and real-time monitoring of dual-species biofilm formation and development. We compared the structural parameters of monospecies and dual-species biofilms containing Pseudomonas aeruginosa (expressing mCherry) and Escherichia coli (expressing green fluorescent protein [GFP]) to understand the interactions in the biofilm. The rate of biovolume increase of each species in monospecies biofilm (2.7 × 105 μm3) was higher than those in a dual-species biofilm (9.68 × 104 μm3); however, synergism was still observed in the dual-species biofilm due to overall increases in biovolume for both species. Synergism was also observed in a dual-species biofilm, where P. aeruginosa forms a "blanket" over E. coli, providing a physical barrier against shear stress in the environment. The microfluidic chip was useful for monitoring the dual-species biofilm in the microenvironment, indicating that different species in a multispecies biofilm exhibit different niches for the survival of the biofilm community. Finally, we demonstrated that the nucleic acids can be extracted from the dual-species biofilm in situ after biofilm imaging analysis. In addition, gene expression supported that the activation and suppression of different quorum sensing genes resulted in the different phenotype seen in the biofilm. This study showed that the integration of microfluidic device with microscopy analysis and molecular techniques could be a promising tool for studying biofilm structure and gene quantification and expression simultaneously. IMPORTANCE In natural or man-made environments, microorganisms exist predominantly as biofilms forming surface-associated bacterial communities embedded in extracellular polymeric substances (EPSs). Often, biofilm reactors used for endpoint and disruptive analyses of biofilm are not suitable for periodic observation of biofilm formation and development. Here, we demonstrate that a microfluidic device with multiple channels and a gradient generator can be useful for high-throughput analysis and real-time monitoring of dual-species biofilm formation and development. Our study revealed synergism in the dual-species biofilm, where P. aeruginosa forms a "blanket" over E. coli, providing a physical barrier against shear stress in the environment. Furthermore, different species in a multispecies biofilm exhibit different niches for the survival of the biofilm community. This study showed that the integration of microfluidic device with microscopy analysis and molecular techniques could be a promising tool for studying biofilm structure and gene quantification and expression simultaneously.

The African Wastewater Resistome: Identifying Knowledge Gaps to Inform Future Research Directions

Antimicrobial resistance (AMR) is a growing global public health threat. Furthermore, wastewater is increasingly recognized as a significant environmental reservoir for AMR. Wastewater is a complex mixture of organic and inorganic compounds, including antibiotics and other antimicrobial agents, discharged from hospitals, pharmaceutical industries, and households. Therefore, wastewater treatment plants (WWTPs) are critical components of urban infrastructure that play a vital role in protecting public health and the environment. However, they can also be a source of AMR. WWTPs serve as a point of convergence for antibiotics and resistant bacteria from various sources, creating an environment that favours the selection and spread of AMR. The effluent from WWTPs can also contaminate surface freshwater and groundwater resources, which can subsequently spread resistant bacteria to the wider environment. In Africa, the prevalence of AMR in wastewater is of particular concern due to the inadequate sanitation and wastewater treatment facilities, coupled with the overuse and misuse of antibiotics in healthcare and agriculture. Therefore, the present review evaluated studies that reported on wastewater in Africa between 2012 and 2022 to identify knowledge gaps and propose future perspectives, informing the use of wastewater-based epidemiology as a proxy for determining the resistome circulating within the continent. The study found that although wastewater resistome studies have increased over time in Africa, this is not the case in every country, with most studies conducted in South Africa. Furthermore, the study identified, among others, methodology and reporting gaps, driven by a lack of skills. Finally, the review suggests solutions including standardisation of protocols in wastewater resistome works and an urgent need to build genomic skills within the continent to handle the big data generated from these studies.

Environmental surveillance of antimicrobial resistance (AMR), perspectives from a national environmental regulator in 2023

The development, and in some cases increasing prevalence, of resistance to antimicrobials used in clinical and veterinary settings has long been recognised. In recent years, the concept of 'One Health' has added recognition of the role that the environment plays in health protection along with the need for protection of the health of the environment itself. Organisations including the World Health Organization, United Nations Environment Programme, and national governments have identified a need for surveillance of antimicrobial resistance in the environment to sit alongside the surveillance carried out in clinical, veterinary and food sectors. However, having recognised the need for environmental surveillance there are multiple challenges in deciding what this should entail. For example, what pathogens or genes to monitor, who or what we wish to protect and what measures we wish to enable to decrease infection risks. That might include sampling near a source of resistant organisms entering the environment or conversely sampling where the exposure actually occurs. Choices need to be made at both policy and technical levels based on the detailed purposes of surveillance. This paper discusses these issues from the perspective of a national environmental regulator.

Synthesis of neodymium ferrite incorporated graphitic carbonitride (NdFe2O4@g-C3N4) and its application in the photodegradation of ciprofloxacin and ampicillin in a water system

Purification of antibiotic-contaminated drinking water sources is faced with limitations. Therefore, this study incorporated neodymium ferrite (NdFe2O4) in graphitic carbonitride (g-C3N4) to form NdFe2O4@g-C3N4 as a photocatalyst for removing ciprofloxacin (CIP) and ampicillin (AMP) from aqueous systems. X-ray diffraction (XRD) revealed a crystallite size of 25.15 nm for NdFe2O4 and 28.49 nm for NdFe2O4@g-C3N4. The bandgap is 2.10 and 1.98 eV for NdFe2O4 and NdFe2O4@g-C3N4, respectively. The transmission electron micrograph (TEM) images of NdFe2O4 and NdFe2O4@g-C3N4 gave an average particle size of 14.10 nm and 18.23 nm, respectively. Scanning electron micrograph (SEM) images showed heterogeneous surfaces with irregular-sized particles suggesting agglomeration at the surfaces. NdFe2O4@g-C3N4 (100.00 ± 0.00% for CIP and 96.80 ± 0.80% for AMP) exhibited better photodegradation efficiency towards CIP and AMP than NdFe2O4 (78.45 ± 0.80% for CIP and 68.25 ± 0.60% for AMP) in a process described by pseudo-first-order kinetics. NdFe2O4@g-C3N4 showed a stable regeneration capacity towards degradation of CIP and AMP with a capacity that is above 95% even at the 15th cycle of treatment. The use of NdFe2O4@g-C3N4 in this study revealed its potential as a promising photocatalyst for removing CIP and AMP in water systems.

Heavy metal co-resistance with antibiotics amongst bacteria isolates from an open dumpsite soil

Heavy metal co-resistance with antibiotics appears to be synergistic in bacterial isolates via similar mechanisms. This synergy has the potential to amplify antibiotics resistance genes in the environment which can be transferred into clinical settings. The aim of this study was to assess the co-resistance of heavy metals with antibiotics in bacteria from dumpsite in addition to physicochemical analysis. Sample collection, physicochemical analysis, and enumeration of total heterotrophic bacteria counts (THBC) were all carried out using standard existing protocols. Identified bacteria isolates were subjected to antibiotics sensitivity test using the Kirby Bauer disc diffusion technique and the resulting multidrug resistant (MDR) isolates were subjected to heavy metal tolerance test using agar dilution technique with increasing concentrations (50, 100, 150, 200 and to 250 μg/ml) of our study heavy metals. THBC ranged from 6.68 to 7.92 × 105 cfu/g. Out of the 20 isolates subjected to antibiotics sensitivity, 50% (n = 10) showed multiple drug resistance and these were B. subtilis, B. cereus, C. freundii, P. aeruginosa, Enterobacter sp, and E. coli (n = 5). At the lowest concentration (50 μg/ml), all the MDR isolates tolerated all the heavy metals, but at 250 μg/ml, apart from cadmium and lead, all test isolates were 100% sensitive to chromium, vanadium and cobalt. The control isolate was only resistant to cobalt and chromium at 50 μg/ml, but sensitive to other heavy metals at all concentrations The level of co-resistance shown by these isolates is a call for concern.

Clinically Relevant β-Lactam Resistance Genes in Wastewater Treatment Plants

Antimicrobial resistance (AMR) is one of the largest global concerns due to its influence in multiple areas, which is consistent with One Health's concept of close interconnections between people, animals, plants, and their shared environments. Antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs) circulate constantly in various niches, sediments, water sources, soil, and wastes of the animal and plant sectors, and is linked to human activities. Sewage of different origins gets to the wastewater treatment plants (WWTPs), where ARB and ARG removal efficiency is still insufficient, leading to their transmission to discharge points and further dissemination. Thus, WWTPs are believed to be reservoirs of ARGs and the source of spreading AMR. According to a World Health Organization report, the most critical pathogens for public health include Gram-negative bacteria resistant to third-generation cephalosporins and carbapenems (last-choice drugs), which represent β-lactams, the most widely used antibiotics. Therefore, this paper aimed to present the available research data for ARGs in WWTPs that confer resistance to β-lactam antibiotics, with a particular emphasis on clinically important life-threatening mechanisms of resistance, including extended-spectrum β-lactamases (ESBLs) and carbapenemases (KPC, NDM).

Non-point source fecal contamination from aging wastewater infrastructure is a primary driver of antibiotic resistance in surface waters

Antibiotic resistance is a global threat to human health. Many surface water resources are environmental hotspots of antibiotic resistant gene (ARG) transfer, with agricultural runoff and human waste highlighted as common sources of ARGs to aquatic systems. Here we quantified fecal marker genes and ARGs in 992 stream water samples collected seasonally during a 5-year period from 115 sites across the Upper Oconee watershed (Georgia, USA), an area characterized by gradients of agricultural and urban development. Widespread fecal contamination was found from humans (48% of samples), ruminants (55%), and poultry (19%), and 73% of samples tested positive for at least one of the six targeted ARGs (ermB, tet(B), bla_CTX-M-1, bla_KPC, bla_SHV, and qnrS). While ARGs were strongly correlated with human fecal markers, many highly contaminated samples were not associated with sewage outfalls, an expected source of fecal and ARG pollution. To determine sources of contamination, we synthesized ARG and fecal marker data with geospatial data on land use/land cover and wastewater infrastructure across the watershed. This novel analysis found strong correlations between ARGs and measures of sewer density, sewer length, and septic system age within sample watersheds, indicating non-point sources of fecal contamination from aging wastewater infrastructure can be critical disseminators of anthropogenic ARGs in the environment.