Airborne bacterial contaminations in typical Chinese wet market with live poultry trade

Antibiotic Abuse in Ornamental Fish: An Overlooked Reservoir for Antibiotic Resistance

Ornamental fish represent a significant aquaculture sector with notable economic value, yet their contribution to antibiotic residues and resistance remains underrecognized. This review synthesizes evidence on widespread and often unregulated antibiotic use-including tetracyclines and fluoroquinolones-in ornamental fish production, transportation, and retail, primarily targeting bacterial diseases such as aeromonosis and vibriosis. Pathogenic microorganisms including Edwardsiella, Flavobacterium, and Shewanella spp. cause diseases like hemorrhagic septicemia, fin rot, skin ulcers, and exophthalmia, impairing fish health and marketability. Prophylactic and therapeutic antibiotic applications elevate antibiotic residues in fish tissues and carriage water, thereby selecting for antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs). These resistant elements pose significant risks to fish health, human exposure via direct contact and bioaerosols, and environmental health through contamination pathways. We emphasize the urgent need for a holistic One Health approach, involving enhanced surveillance, stringent regulatory oversight, and adoption of alternative antimicrobial strategies, such as probiotics and advanced water treatments. Coordinated global actions are crucial to effectively mitigate antibiotic resistance within the ornamental fish industry, ensuring sustainable production, safeguarding public health, and protecting environmental integrity.

Explore the Contamination of Antibiotic Resistance Genes (ARGs) and Antibiotic-Resistant Bacteria (ARB) of the Processing Lines at Typical Broiler Slaughterhouse in China

Farms are a major source of antibiotic resistance genes (ARGs) and antibiotic-resistant bacteria (ARB), and previous research mainly focuses on polluted soils and breeding environments. However, slaughtering is an important link in the transmission of ARGs and ARB from farmland to dining table. In this study, we aim to reveal the pollution of ARGs and ARB in the slaughter process of broilers. First, by qualitative and quantitative analysis of ARGs in samples collected from the broiler slaughtering and processing production chain, the contamination level of ARGs was reflected; secondly, potential hosts for ARGs and microbial community were analyzed to reflect the possible transmission rules; thirdly, through the antibiotic susceptibility spectrum analysis of four typical food-borne pathogens, the distribution of ARB was revealed. The results showed that 24 types of ARGs were detected positive on the broiler slaughter production line, and tetracycline-resistance genes (20.45%) were the most frequently detected. The types of ARGs vary with sampling process, and all sampling links contain high levels of sul2 and intI1. The most abundant ARGs were detected in chicken surface in the scalding stage and entrails surface in the evisceration stage. There was a significant correlation between intI1 and tetM, suggesting that tetM might be able to enter the human food chain through class-1 integrons. The host range of the oqxB gene is the most extensive, including Sphingobacterium, Bacteroidia unclassified, Rothia, Microbacterium, Algoriella, etc. In the relevant links of the slaughter production line, the microbial community structure is similar. Removing viscera may cause diffusion of ARGs carried by intestinal microorganisms and contaminate chicken and following processing production. The four food-borne pathogens we tested are widely present in all aspects of the slaughter process, and most of them have multi-drug resistance and even have a high degree of resistance to some veterinary drugs banned by the Ministry of Agriculture. Our study preliminarily revealed the pollution of ARGs and ARB in the slaughter process of broilers, and these results are helpful to carry out food safety risk assessment and formulate corresponding control measures.

A community action network-based intervention for improving knowledge of zoonoses among wildlife hunters and traders in Epe, Lagos, Nigeria

The West Africa One Health project is a multi-country project designed to utilise the One Health approach and deploy the Community Action Networks (CAN), a concept rooted in the principles of community-based participatory research, to improve knowledge of high-risk communities on zoonoses. The majority of emerging zoonoses occur at the human-wildlife interface, of which wildlife hunters and traders are critical stakeholders. We assessed the effectiveness of a CAN-based intervention involving the use of a video documentary and case studies as model tools in improving the knowledge of zoonoses among wildlife hunters and traders in Epe, an established hunting community in Lagos State, Nigeria. A single-group pre-post design involving a total of 39 consenting registered wildlife stakeholders was adopted. A pre-tested, semi-structured, interviewer-administered questionnaire was used to obtain data on the participant's sociodemographic characteristics, awareness level, and knowledge of zoonoses pre and post CAN-based intervention. Data were analysed using descriptive statistics McNemar and Wilcoxon Signed Ranks tests at a 5% level of significance. The mean age of the participants was 46.7 ± 10.9 years. Most (76.9%) identified as male and had at least secondary education (89.7%). The number of participants who were aware that diseases could be contracted from animals and that it could be through inhalation and close contact increased significantly from 13 (33.3%), 2 (5.1%), and 9 (23.1%) pre-intervention to 37 (94.9%), 11 (28.2%), and 21 (53.8%) post-intervention, respectively. The overall median knowledge score increased significantly from 1 (Interquartile range (IQR): 0-2) pre-intervention to 3 (IQR: 2-4) post-intervention. The CAN-based intervention involving the use of a video documentary and case studies as model tools was effective in improving the knowledge of zoonoses among wildlife hunters and traders in the hunting community and may be beneficial for future practice.

Characteristics and health impacts of bioaerosols in animal barns: A comprehensive study

Bioaerosols produced during animal production have potential adverse effects on the health of workers and animals. Our objective was to investigate characteristics, antibiotic-resistance genes (ARGs), and health risks of bioaerosols in various animal barns. Poultry and swine barns had high concentrations of airborne bacteria (11156 and 10917 CFU/m3, respectively). Acinetobacter, Clostridium sensu stricto, Corynebacterium, Pseudomonas, Psychrobacter, Streptococcus, and Staphylococcus were dominant pathogenic bacteria in animal barns, with Firmicutes being the most abundant bacterial phylum. Based on linear discriminant analysis effect size (LEfSe), there were more discriminative biomarkers in cattle barns than in poultry or swine barns, although the latter had the highest abundance of bacterial pathogens and high abundances of ARGs (including tetM, tetO, tetQ, tetW sul1, sul2, ermA, ermB) and intI1). Based on network analyses, there were higher co-occurrence patterns between bacteria and ARGs in bioaerosol from swine barns. Furthermore, in these barns, relative abundance of bacteria in bioaerosol samples was greatly affected by environmental factors, mainly temperature, relative humidity, and concentrations of CO2, NH3, and PM2.5. This study provided novel data regarding airborne bio-contaminants in animal enclosures and an impetus to improve management to reduce potential health impacts on humans and animals.

Limiting the spillover of zoonotic pathogens from traditional food markets in developing countries and a new market design for risk-proofing

Traditional food markets are age-old systems that primarily serve the food supply needs of society's less affluent sectors, often operating with minimal infrastructure. These markets are prevalent in low and middle-income countries. However, their hygienic conditions are frequently suboptimal, potentially fostering the emergence and spread of presumptive zoonotic diseases. The recent emergence of zoonotic or potentially zoonotic diseases and their possible links to traditional food markets underscore the need for focused attention on this overlooked issue. The socioeconomic characteristics of traditional food markets reveal that despite the risk of zoonotic pathogen spread, these markets play a crucial role for large segments of the population. These individuals rely on such markets for their livelihood, food, and nutrition. Therefore, a comprehensive set of measures addressing various aspects of traditional food markets is necessary to manage and mitigate the risks of potential zoonotic disease emergence. In this article, we explore various facets of traditional food markets, paying special attention to the risks of zoonotic diseases that urgently require stakeholder attention. We also propose a new market design to prevent the risk of zoonotic spillover and advocate for the development of a Market Hygiene Index for these markets.

Airborne bacterial community and antibiotic resistome in the swine farming environment: Metagenomic insights into livestock relevance, pathogen hosts and public risks

Globally extensive use of antibiotics has accelerated antimicrobial resistance (AMR) in the environment. As one of the biggest antibiotic consumers, livestock farms are hotspots in AMR prevalence, especially those in the atmosphere can transmit over long distances and pose inhalation risks to the public. Here, we collected total suspended particulates in swine farms and ambient air of an intensive swine farming area. Bacterial communities and antibiotic resistomes were analyzed using amplicon and metagenomic sequencing approaches. AMR risks and inhalation exposure to potential human-pathogenic antibiotic-resistant bacteria (HPARB) were subsequently estimated with comparison to the reported hospital samples. The results show that swine farms shaped the airborne bacterial community by increasing abundances, reducing diversities and shifting compositions. Swine feces contributed 77% of bacteria to swine farm air, and about 35% to ambient air. Airborne antibiotic resistomes in swine farms mainly conferred resistance to tetracyclines, aminoglycosides and lincosamides, and over 48% were originated from swine feces. Distinct to the hospital air, Firmicutes were dominant bacteria in swine farming environments with conditional pathogens including Clostridium, Streptococcus and Aerococcus being major hosts of antibiotic resistance genes (ARGs). Therein, genomes of S. alactolyticus carrying (transposase/recombinase-associated) ARGs and virulence factor genes were retrieved from the metagenomes of all swine feces and swine farm air samples, but they were not detected in any hospital air samples. This suggests the indication of S. alactolyticus in swine farming environments with potential hazards to human health. Swine farm air faced higher AMR risks than hospital air and swine feces. The inhalation intake of HPARB by a swine farm worker was about three orders of magnitude higher than a person who works in the hospital. Consequently, this study depicted atmospheric transmission of bacteria and antibiotic resistomes from swine feces to the environment.

City-scale distribution of airborne antibiotic resistance genes

Concerns around urban air quality have been increasing worldwide due to large-scale urbanization. A large volume of work has been focused on the chemical pollutants in the air and their impacts on human health. However, the profile of airborne microbial contaminants, especially antibiotic resistance genes (ARGs), is largely understudied. Here, high-throughput quantitative PCR (HT-qPCR) was employed to explore the temporal and spatial distribution of airborne ARGs from 11 sites with various functional zones and different urbanization levels within Xiamen, China. A total of 104 unique ARGs and 23 mobile genetic elements (MGEs) were detected across all samples. Temporal shift was observed in the distribution of ARG profiles, with significantly higher relative abundance of ARGs detected in summer than that in spring. Temperature is the key predictor of the total relative abundance of ARGs and MGEs in summer, while PM_2.5 and PM₁₀ were the two most important factors affecting the abundance in spring. Our findings suggest that urban aerosols accommodate rich and dynamic ARGs and MGEs, and emphasize the role of temperature, air quality and anthropogenic activities in shaping the profile of ARGs.

Risk of Viral Infectious Diseases from Live Bats, Primates, Rodents and Carnivores for Sale in Indonesian Wildlife Markets

Southeast Asia is considered a global hotspot of emerging zoonotic diseases. There, wildlife is commonly traded under poor sanitary conditions in open markets; these markets have been considered 'the perfect storm' for zoonotic disease transmission. We assessed the potential of wildlife trade in spreading viral diseases by quantifying the number of wild animals of four mammalian orders (Rodentia, Chiroptera, Carnivora and Primates) on sale in 14 Indonesian wildlife markets and identifying zoonotic viruses potentially hosted by these animals. We constructed a network analysis to visualize the animals that are traded alongside each other that may carry similar viruses. We recorded 6725 wild animals of at least 15 species on sale. Cities and markets with larger human population and number of stalls, respectively, offered more individuals for sale. Eight out of 15 animal taxa recorded are hosts of 17 zoonotic virus species, nine of which can infect more than one species as a host. The network analysis showed that long-tailed macaque has the greatest potential for spreading viral diseases, since it is simultaneously the most traded species, sold in 13/14 markets, and a potential host for nine viruses. It is traded alongside pig-tailed macaques in three markets, with which it shares six viruses in common (Cowpox, Dengue, Hepatitis E, Herpes B, Simian foamy, and Simian retrovirus type D). Short-nosed fruit bats and large flying foxes are potential hosts of Nipah virus and are also sold in large quantities in 10/14 markets. This study highlights the need for better surveillance and sanitary conditions to avoid the negative health impacts of unregulated wildlife markets.

Understanding Factors that Shape Exposure to Zoonotic and Food-Borne Diseases Across Wild Meat Trade Chains

The rise of zoonotic disease-related public health crises has sparked calls for policy action, including calls to close wildlife markets. Yet, these calls often reflect limited understanding of where, precisely, exposure to risk occurs along wildlife and wild meat trade chains. They also threaten to negatively impact food security and livelihoods. From a public health perspective, it is important to understand the practices that shape food safety all along the trade chain, resulting in meat that is either safe to eat or managed as a potential vector of pathogens. This article uses ethnographic methods to examine the steps that lead a wild animal from the forest to the plate of an urban consumer in Yangambi and Kisangani in the Democratic Republic of Congo (DRC). Focusing on hunters, village-level consumers, transporters, market traders and urban consumers, we highlight specific practices that expose different actors involved in the trade chain to wild meat related health risks, including exposure to food borne illnesses from contaminated meat and zoonotic pathogens through direct contact with wild animals, and the local practices in place to reduce the same. We discuss interventions that could help prevent and mitigate zoonotic and food borne disease risks associated with wild meat trade chains.

A systematic review of enteric pathogens and antibiotic resistance genes in outdoor urban aerosols

Aerosol transport of enteric microbiota including fecal pathogens and antimicrobial resistance genes (ARGs) has been documented in a range of settings but remains poorly understood outside indoor environments. We conducted a systematic review of the peer-reviewed literature to summarize evidence on specific enteric microbiota including enteric pathogens and ARGs that have been measured in aerosol samples in urban settings where the risks of outdoor exposure and antibiotic resistance (AR) spread may be highest. Following PRISMA guidelines, we conducted a key word search for articles published within the years 1990-2020 using relevant data sources. Two authors independently conducted the keyword searches of databases and conducted primary and secondary screenings before merging results. To be included, studies contained extractable data on enteric microbes and AR in outdoor aerosols regardless of source confirmation and reported on qualitative, quantitative, or viability data on enteric microbes or AR. Qualitative analyses and metric summaries revealed that enteric microbes and AR have been consistently reported in outdoor aerosols, generally via relative abundance measures, though gaps remain preventing full understanding of the role of the aeromicrobiological pathway in the fate and transport of enteric associated outdoor aerosols. We identified remaining gaps in the evidence base including a need for broad characterization of enteric pathogens in bioaerosols beyond bacterial genera, a need for greater sampling in locations of high enteric disease risk, and a need for quantitative estimation of microbial and nucleic acid densities that may be applied to fate and transport models and in quantitative microbial risk assessment.

Critical review of antibiotic resistance genes in the atmosphere

We conducted a critical review to establish what is known about the sources, characteristics, and dissemination of ARGs in the atmosphere. We identified 52 papers that reported direct measurements of bacterial ARGs in air samples and met other inclusion criteria. The settings of the studies fell into the following categories: urban, rural, hospital, industrial, wastewater treatment plants (WWTPs), composting and landfill sites, and indoor environments. Certain genes were commonly studied and generally abundant: sul1, intI1, β-lactam ARGs, and tetracycline ARGs. Abundances of total ARGs varied by season and setting, with air in urban areas having higher ARG abundance than rural areas during the summer and vice versa during the winter. There was greater consistency in the types and abundances of ARGs throughout the seasons in urban areas. Human activity within indoor environments was also linked to increased ARG content (abundance, diversity, and concentration) in the air. Several studies found that human exposure to ARGs through inhalation was comparable to exposure through drinking water or ingesting soil. Detection of ARGs in air is a developing field, and differences in sampling and analysis methods reflect the many possible approaches to studying ARGs in air and make direct comparisons between studies difficult. Methodologies need to be standardized to facilitate identification of the dominant ARGs in the air, determine their major sources, and quantify the role of atmospheric transport in dissemination of ARGs in the environment. With such knowledge we can develop better policies and guidelines to limit the spread of antimicrobial resistance.

Inhalable Antibiotic Resistome from Wastewater Treatment Plants to Urban Areas: Bacterial Hosts, Dissemination Risks, and Source Contributions

Antibiotic resistance genes (ARGs) are commonly detected in the atmosphere, but questions remain regarding their sources and relative contributions, bacterial hosts, and corresponding human health risks. Here, we conducted a qPCR- and metagenomics-based investigation of inhalable fine particulate matter (PM_2.5) at a large wastewater treatment plant (WWTP) and in the ambient air of Hong Kong, together with an in-depth analysis of published data of other potential sources in the area. PM_2.5 was observed with increasing enrichment of total ARGs along the coastal-urban-WWTP gradient and clinically relevant ARGs commonly identified in urban and WWTP sites, illustrating anthropogenic impacts on the atmospheric accumulation of ARGs. With certain kinds of putative antibiotic-resistant pathogens detected in urban and WWTP PM_2.5, a comparable proportion of ARGs that co-occurred with MGEs was found between the atmosphere and WWTP matrices. Despite similar emission rates of bacteria and ARGs within each WWTP matrix, about 11-13% of the bacteria and >57% of the relevant ARGs in urban and WWTP PM_2.5 were attributable to WWTPs. Our study highlights the importance of WWTPs in disseminating bacteria and ARGs to the ambient air from a quantitative perspective and, thus, the need to control potential sources of inhalation exposure to protect the health of urban populations.

The air-borne antibiotic resistome: Occurrence, health risks, and future directions

Antibiotic resistance comprising of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) is an emerging problem causing global human health risks. Several reviews exist on antibiotic resistance in various environmental compartments excluding the air-borne resistome. An increasing body of recent evidence exists on the air-borne resistome comprising of antibiotic resistance in air-borne bioaerosols from various environmental compartments. However, a comprehensive review on the sources, dissemination, behavior, fate, and human exposure and health risks of the air-borne resistome is still lacking. Therefore, the current review uses the source-pathway-receptor-impact-mitigation framework to investigate the air-borne resistome. The nature and sources of antibiotic resistance in the air-borne resistome are discussed. The dissemination pathways, and environmental and anthropogenic drivers accounting for the transfer of antibiotic resistance from sources to the receptors are highlighted. The human exposure and health risks posed by air-borne resistome are presented. A health risk assessment and mitigation strategy is discussed. Finally, future research directions including key knowledge gaps are summarized.

A review of the emergence of antibiotic resistance in bioaerosols and its monitoring methods

Despite significant public health concerns regarding infectious diseases in air environments, potentially harmful microbiological indicators, such as antibiotic resistance genes (ARGs) in bioaerosols, have not received significant attention. Traditionally, bioaerosol studies have focused on the characterization of microbial communities; however, a more serious problem has recently arisen due to the presence of ARGs in bioaerosols, leading to an increased prevalence of horizontal gene transfer (HGT). This constitutes a process by which bacteria transfer genes to other environmental media and consequently cause infectious disease. Antibiotic resistance in water and soil environments has been extensively investigated in the past few years by applying advanced molecular and biotechnological methods. However, ARGs in bioaerosols have not received much attention. In addition, ARG and HGT profiling in air environments is greatly limited in field studies due to the absence of suitable methodological approaches. Therefore, this study comprehensively describes recent findings from published studies and some of the appropriate molecular and biotechnological methods for monitoring antibiotic resistance in bioaerosols. In addition, this review discusses the main knowledge gaps regarding current methodological issues and future research directions.

Abundance and diversity of antibiotic resistance genes possibly released to ambient air by experiments in biology laboratories

Antibiotic resistance genes (ARG) have been considered as a global emerging threat to public health systems. As special locations where both antibiotics and ARGs are directly used, biology laboratories are poorly studied but potential important emission sources where not only the environmental stress is strong but also obtaining resistance is much easier comparing to other well studied hot spots including farms, hospitals, wastewater treatment plants and landfills where antibiotics but not ARGs are used or discharged. Therefore, in this study, 11 Swiss biology laboratories working on different fields and located in the city center, suburb and rural area were studied to reveal the abundance and diversity of airborne ARGs in them and their surrounding areas with Colony-forming units (CFU) cultivation and quantitative Polymerase Chain Reaction (qPCR). Most biology laboratories did not discharge significant amounts or varieties of ARGs and cultivable bacteria via air. No correlation was found between the number of CFUs and the abundance of 16S rRNA, but two clusters of correlated airborne ARGs, the animal husbandry related cluster, and city and hospital related cluster were identified in this study. Although most biology laboratories may not be the emission sources of a wide variety of airborne ARGs, the ARGs in the animal husbandry related cluster which are abundant in the animal laboratories and aadA1 which is abundant in the laboratories working on other eukaryocytes need to be furtherly studied to make sure if they are potential health risks for the researchers.

Detection and Quantification of Enteric Pathogens in Aerosols Near Open Wastewater Canals in Cities with Poor Sanitation

Urban sanitation infrastructure is inadequate in many low-income countries, leading to the presence of highly concentrated, uncontained fecal waste streams in densely populated areas. Combined with mechanisms of aerosolization, airborne transport of enteric microbes and their genetic material is possible in such settings but remains poorly characterized. We detected and quantified enteric pathogen-associated gene targets in aerosol samples near open wastewater canals (OWCs) or impacted (receiving sewage or wastewater) surface waters and control sites in La Paz, Bolivia; Kanpur, India; and Atlanta, USA, via multiplex reverse-transcription qPCR (37 targets) and ddPCR (13 targets). We detected a wide range of enteric targets, some not previously reported in extramural urban aerosols, with more frequent detections of all enteric targets at higher densities in La Paz and Kanpur near OWCs. We report density estimates ranging up to 4.7 × 10² gc per m_air³ across all targets including heat-stable enterotoxigenic Escherichia coli, Campylobacter jejuni, enteroinvasive E. coli/Shigella spp., Salmonella spp., norovirus, and Cryptosporidium spp. Estimated 25, 76, and 0% of samples containing positive pathogen detects were accompanied by culturable E. coli in La Paz, Kanpur, and Atlanta, respectively, suggesting potential for viability of enteric microbes at the point of sampling. Airborne transmission of enteric pathogens merits further investigation in cities with poor sanitation.

More diversified antibiotic resistance genes in chickens and workers of the live poultry markets

BACKGROUND

Poultry farms and LPMs are a reservoir of antimicrobial resistant bacteria and resistance genes from feces. The LPM is an important interface between humans, farm animals, and environments in a typical urban environment, and it is considered a reservoir for ARGs and viruses. However, the antibiotic resistomes shared between chicken farms and LPMs, and that of LPM workers and people who have no contact with the LPMs remains unknown.

METHODS

We characterized the resistome and bacterial microbiome of farm chickens and LPMs and LPM workers and control subjects. The mobile ARGs identified in chickens and the distribution of the mcr-family genes in publicly bacterial genomes and chicken gut metagenomes was analyzed, respectively. In addition, the prevalence of mcr-1 in LPMs following the ban on colistin-positive additives in China was explored.

RESULTS

By profiling the microbiomes and resistomes in chicken farms, LPMs, LPM workers, and LPM environments, we found that the bacterial community composition and resistomes were significantly different between the farms and the LPMs, and the LPM samples possessed more diversified ARGs (59 types) than the farms. Some mobile ARGs, such as mcr-1 and tet(X3), identified in chicken farms, LPMs, LPM workers, and LPM environments were also harbored by human clinical pathogens. Moreover, we found that the resistomes were significantly different between the LPM workers and those who have no contact with the LPMs, and more diversified ARGs (188 types) were observed in the LPM workers. It is also worth noting that mcr-10 was identified in both human (5.2%, 96/1,859) and chicken (1.5%, 14/910) gut microbiomes. Although mcr-1 prevalence decreased significantly in the LPMs across the eight provinces in China, from 190/333 (57.1%) samples in September 2016-March 2017 to 208/544 (38.2%) samples in August 2018-May 2019, it is widespread and continuous in the LPMs.

CONCLUSION

Live poultry trade has a significant effect on the diversity of ARGs in LPM workers, chickens, and environments in China, driven by human selection with the live poultry trade. Our findings highlight the live poultry trade as ARG disseminators into LPMs, which serve as an interface of LPM environments even LPM workers, and that could urge Government to have better control of LPMs in China. Further studies on the factors that promote antibiotic resistance exchange between LPM environments, human commensals, and pathogens, are warranted.

Bacteria and Their Antibiotic Resistance Profiles in Ambient Air in Accra, Ghana, February 2020: A Cross-Sectional Study

Inappropriate use of antibiotics has led to the presence of antibiotic-resistant bacteria in ambient air. There is no published information about the presence and resistance profiles of bacteria in ambient air in Ghana. We evaluated the presence and antibiotic resistance profiles of selected bacterial, environmental and meteorological characteristics and airborne bacterial counts in 12 active air quality monitoring sites (seven roadside, two industrial and three residential) in Accra in February 2020. Roadside sites had the highest median temperature, relative humidity, wind speed and PM₁₀ concentrations, and median airborne bacterial counts in roadside sites (115,000 CFU/m³) were higher compared with industrial (35,150 CFU/m³) and residential sites (1210 CFU/m³). Bacillus species were isolated in all samples and none were antibiotic resistant. There were, however, Pseudomonas aeruginosa, Escherichia coli, Pseudomonas species, non-hemolytic Streptococci, Coliforms and Staphylococci species, of which six (50%) showed mono-resistance or multidrug resistance to four antibiotics (penicillin, ampicillin, ciprofloxacin and ceftriaxone). There was a positive correlation between PM₁₀ concentrations and airborne bacterial counts (r_s = 0.72), but no correlations were found between PM₁₀ concentrations and the pathogenic bacteria nor their antibiotic resistance. We call for the expansion of surveillance of ambient air to other cities of Ghana to obtain nationally representative information.

Open Waste Canals as Potential Sources of Antimicrobial Resistance Genes in Aerosols in Urban Kanpur, India

Understanding the movement of antimicrobial resistance genes (ARGs) in the environment is critical to managing their spread. To assess potential ARG transport through the air via urban bioaerosols in cities with poor sanitation, we quantified ARGs and a mobile integron (MI) in ambient air over periods spanning rainy and dry seasons in Kanpur, India (n = 53), where open wastewater canals (OWCs) are prevalent. Gene targets represented major antibiotic groups-tetracyclines (tetA), fluoroquinolines (qnrB), and beta-lactams (blaTEM)-and a class 1 mobile integron (intI1). Over half of air samples located near, and up to 1 km from OWCs with fecal contamination (n = 45) in Kanpur had detectable targets above the experimentally determined limits of detection (LOD): most commonly intI1 and tetA (56% and 51% of samples, respectively), followed by blaTEM (8.9%) and qnrB (0%). ARG and MI densities in these positive air samples ranged from 6.9 × 101 to 5.2 × 103 gene copies/m3 air. Most (7/8) control samples collected 1 km away from OWCs were negative for any targets. In comparing experimental samples with control samples, we found that intI1 and tetA densities in air are significantly higher (P = 0.04 and P = 0.01, respectively, alpha = 0.05) near laboratory-confirmed fecal contaminated waters than at the control site. These data suggest increased densities of ARGs and MIs in bioaerosols in urban environments with inadequate sanitation. In such settings, aerosols may play a role in the spread of AR.

An Investigation of Airborne Bioaerosols and Endotoxins Present in Indoor Traditional Wet Markets before and after Operation in Taiwan: A Case Study

Customers in Taiwan prefer to purchase fresh foods and household supplies at indoor traditional wet markets (TWMs). The health risk to indoor TWM staff exposed to bioaerosols needs to be evaluated, since these workers spend long periods of time in the market for stall preparation, selling, and stall cleaning. This study investigated the bioaerosols present in two indoor TWMs. The results showed that the cleaning process at Market A after operations, involving the use of an agitated waterspout, was able to decrease the concentration of bacterial bioaerosols (BBs) by an average of 64%, while at the same time increasing the concentration of fungal bioaerosols (FBs) by about 2.4 fold. The chemical sanitization process at Market B after operations was able to bring about average decreases of 30.8% in BBs and 19.2% in FBs, but the endotoxin concentration increased. Hotspots were found to be associated with vendors of fresh, live poultry and fresh, raw meat/seafood. Pseudomonas spp. and Clostridiumperfringens, both of which can be pathogenic, were found to be the dominant species present in these markets, making up 35.18% to 48.74% and 9.64% to 11.72% of the bacteria present, respectively. Our results provide fundamental information on the distributions of bioaerosols and endotoxins within indoor TWMs both before and after operation.

Antimicrobial resistance genes are enriched in aerosols near impacted urban surface waters in La Paz, Bolivia

Antibiotic resistance poses a major global health threat. Understanding emergence and dissemination of antibiotic resistance in environmental media is critical to the design of control strategies. Because antibiotic resistance genes (ARGs) may be aerosolized from contaminated point sources and disseminated more widely in localized environments, we assessed ARGs in aerosols in urban La Paz, Bolivia, where wastewater flows in engineered surface water channels through the densely populated urban core. We quantified key ARGs and a mobile integron (MI) via ddPCR and E. coli spp. as a fecal indicator by culture over two years during both the rainy and dry seasons in sites near wastewater flows. ARG targets represented major antibiotic groups-tetracyclines (tetA), fluoroquinolines (qnrB), and beta-lactams (blaTEM)-and an MI (intI1) represented the potential for mobility of genetic material. Most air samples (82%) had detectable targets above the experimentally determined LOD: most commonly blaTEM and intI1 (68% and 47% respectively) followed by tetA and qnrB (17% and 11% respectively). ARG and MI densities in positive air samples ranged from 1.3 × 101 to 6.6 × 104 gene copies/m3 air. Additionally, we detected culturable E. coli in the air (52% of samples <1 km from impacted surface waters) with an average density of 11 CFU/m3 in positive samples. We observed decreasing density of blaTEM with increasing distance up to 150 m from impacted surface waters. To our knowledge this is the first study conducting absolute quantification and a spatial analysis of ARGs and MIs in ambient urban air of a city with contaminated surface waters. Environments in close proximity to urban wastewater flows in this setting may experience locally elevated concentrations of ARGs, a possible concern for the emergence and dissemination of antimicrobial resistance in cities with poor sanitation.

Municipal Solid Waste Treatment System Increases Ambient Airborne Bacteria and Antibiotic Resistance Genes

Landfill and incineration are the primary disposal practices for municipal solid waste (MSW) and have been considered as the critical reservoir of antibiotic resistance genes (ARGs). However, the possible transmission of ARGs from the municipal solid waste treatment system (MSWT system) to ambient air is still unclear. In this study, we collected inside and ambient air samples (PM₁₀ and PM_2.5) and potential source samples (leachate and solid waste) in the MSWT system. The results showed that the MSWT system contributed to the increased ambient airborne bacteria and associated ARGs. Forty-one antibiotic-resistant bacteria (ARB) harboring bla_TEM-1 were isolated, and the full-length nucleotide sequences of the bla_TEM-1 gene (harbored by identical bacillus) from air (downwind samples) were 100% identical with those in the leachate and solid waste, indicating that the MSWT system was the important source of disperse bacteria and associated ARGs in the ambient air. The daily intake (DI) burden level of ARGs via PM inhalation was comparable with that via ingestion of drinking water but lower than the DI level via ingestion of raw vegetables. The antibiotic-resistant opportunistic pathogen Bacillus cereus was isolated from air, with a relatively high DI level of Bacillus via inhalation (10⁴-10⁶ copies/day) in the MSWT system. This study highlights the key pathway of airborne ARGs to human exposure.

Quantification of Airborne Resistant Organisms With Temporal and Spatial Diversity in Bangladesh: Protocol for a Cross-Sectional Study

BACKGROUND

Antimicrobial resistance is a widespread, alarming issue in global health and a significant contributor to human death and illness, especially in low and middle-income countries like Bangladesh. Despite extensive work conducted in environmental settings, there is a scarcity of knowledge about the presence of resistant organisms in the air.

OBJECTIVE

The objective of this protocol is to quantify and characterize the airborne resistomes in Bangladesh, which will be a guide to identify high-risk environments for multidrug-resistant pathogens with their spatiotemporal diversity.

METHODS

This is a cross-sectional study with an environmental, systematic, and grid sampling strategy focused on collecting air samples from different outdoor environments during the dry and wet seasons. The four environmental compartments are the frequent human exposure sites in both urban and rural settings: urban residential areas (n=20), live bird markets (n=20), rural households (n=20), and poultry farms (n=20). We obtained air samples from 80 locations in two seasons by using an active microbial air sampler. From each location, five air samples were collected in different media to yield the total bacterial count of 3rd generation cephalosporin (3GC) resistant Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae, vancomycin-resistant Enterococci and methicillin-resistant Staphylococcus aureus.

RESULTS

The study started in January 2018, and the collection of air samples was completed in November 2018. We have received 800 air samples from 80 study locations in both dry and wet seasons. Currently, the laboratory analysis is ongoing, and we expect to receive the preliminary results by October 2019. We will publish the complete result as soon as we clean and analyze the data and draft the manuscript.

CONCLUSIONS

The existence of resistant bacteria in the air like those producing extended-spectrum beta-lactamases, carbapenem-resistant Enterobacteriaceae, vancomycin-resistant Enterococci, and methicillin-resistant Staphylococcus aureus will justify our hypothesis that the outdoor environment (air) in Bangladesh acts as a reservoir for bacteria that carry genes conferring resistance to antibiotics. To our knowledge, this is the first study to explore the presence of superbugs in the air in commonly exposed areas in Bangladesh.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/14574.

Airborne microbial communities in the atmospheric environment of urban hospitals in China

Clinically relevant antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in bioaerosols have become a greater threat to public health. However, few reports have shown that ARB and ARGs were found in the atmosphere. High-throughput sequencing applied to environmental sciences has enhanced the exploration of microbial populations in atmospheric samples. Thus, five nosocomial bioaerosols were collected, and the dominant microbial and pathogenic microorganisms were identified by high-throughput sequencing in this study. The results suggested that the dominant microorganisms at the genus level were Massilia, Sphingomonas, Methylobacterium, Methylophilus, Micrococcineae, and Corynebacterineae. The most abundant pathogenic microorganisms were Staphylococcus saprophyticus, Corynebacterium minutissimum, Streptococcus pneumoniae, Escherichia coli, Arcobacter butzleri, Aeromonas veronii, Pseudomonas aeruginosa, and Bacillus cereus. The relationship between microbial communities and environmental factors was evaluated with canonical correspondence analysis (CCA). Meanwhile, differences in the pathogenic bacteria between bioaerosols and dust in a typical hospital was investigated. Furthermore, cultivable Staphylococcus isolates with multi-drug resistance phenotype (>3 antibiotics) in the inpatient departments were much higher than those in the transfusion area and out-patient departments, possibly attributed to the dense usage of antibiotics in inpatient departments. The results of this study might be helpful for scientifically air quality control in hospitals.

Lessons from the Environmental Antibiotic Resistome

Antibiotic resistance is a global public health issue of growing proportions. All antibiotics are susceptible to resistance. The evidence is now clear that the environment is the single largest source and reservoir of resistance. Soil, aquatic, atmospheric, animal-associated, and built ecosystems are home to microbes that harbor antibiotic resistance elements and the means to mobilize them. The diversity and abundance of resistance in the environment is consistent with the ancient origins of antibiotics and a variety of studies support a long natural history of associated resistance. The implications are clear: Understanding the evolution of resistance in the environment, its diversity, and mechanisms is essential to the management of our existing and future antibiotic resources.