Population structure and history of Mycobacterium bovis European 3 clonal complex reveal transmission across ecological corridors of unrecognized importance in Portugal.

Mycobacterium bovis causes animal tuberculosis in livestock and wildlife, with an impact on animal health and production, wildlife management, and public health. In this work, we sampled a multi-host tuberculosis community from the official hotspot risk area of Portugal over 16 years, generating the largest available data set in the country. Using phylogenetic and ecological modeling, we aimed to reconstruct the history of circulating lineages across the livestock-wildlife interface to inform intervention and the implementation of genomic surveillance within the official eradication plan. We find evidence for the co-circulation of M. bovis European 1 (Eu1), Eu2, and Eu3 clonal complexes, with Eu3 providing sufficient temporal signal for further phylogenetic investigation. The Eu3 most recent common ancestor (bovine) was dated in the 1990s, subsequently transitioning to wildlife (red deer and wild boar). Isolate clustering based on sample metadata was used to inform phylogenetic inference, unravelng frequent transmission between two clusters that represent an ecological corridor of previously unrecognized importance in Portugal. The latter was associated with transmission at the livestock-wildlife interface toward locations with higher temperature and precipitation, lower agriculture and road density, and lower host densities. This is the first analysis of M. bovis Eu3 complex in Iberia, shedding light on background ecological factors underlying long-term transmission and informing where efforts could be focused within the larger hotspot risk area of Portugal. IMPORTANCE: Efforts to strengthen surveillance and control of animal tuberculosis (TB) are ongoing worlwide. Here, we developed an eco-phylodynamic framework based on discrete phylogenetic approaches informed by M. bovis whole-genome sequence data representing a multi-host transmission system at the livestock-wildlife interface, within a rich ecological landscape in Portugal, to understand transmission processes and translate this knowledge into disease management benefits. We find evidence for the co-circulation of several M. bovis clades, with frequent transmission of the Eu3 lineage among cattle and wildlife populations. Most transition events between different ecological settings took place toward host, climate and land use gradients, underscoring animal TB expansion and a potential corridor of unrecognized importance for M. bovis maintenance. Results stress that animal TB is an established wildlife disease without ecological barriers, showing that control measures in place are insufficient to prevent long-distance transmission and spillover across multi-host communities, demanding new interventions targeting livestock-wildlife interactions.

Rescue of Mycobacterium bovis DNA Obtained from Cultured Samples during Official Surveillance of Animal TB: Key Steps for Robust Whole Genome Sequence Data Generation.

Epidemiological surveillance of animal tuberculosis (TB) based on whole genome sequencing (WGS) of Mycobacterium bovis has recently gained track due to its high resolution to identify infection sources, characterize the pathogen population structure, and facilitate contact tracing. However, the workflow from bacterial isolation to sequence data analysis has several technical challenges that may severely impact the power to understand the epidemiological scenario and inform outbreak response. While trying to use archived DNA from cultured samples obtained during routine official surveillance of animal TB in Portugal, we struggled against three major challenges: the low amount of M. bovis DNA obtained from routinely processed animal samples; the lack of purity of M. bovis DNA, i.e., high levels of contamination with DNA from other organisms; and the co-occurrence of more than one M. bovis strain per sample (within-host mixed infection). The loss of isolated genomes generates missed links in transmission chain reconstruction, hampering the biological and epidemiological interpretation of data as a whole. Upon identification of these challenges, we implemented an integrated solution framework based on whole genome amplification and a dedicated computational pipeline to minimize their effects and recover as many genomes as possible. With the approaches described herein, we were able to recover 62 out of 100 samples that would have otherwise been lost. Based on these results, we discuss adjustments that should be made in official and research laboratories to facilitate the sequential implementation of bacteriological culture, PCR, downstream genomics, and computational-based methods. All of this in a time frame supporting data-driven intervention.

Source Attribution of Antibiotic Resistance Genes in Estuarine Aquaculture: A Machine Learning Approach.

Aquaculture located in urban river estuaries, where other anthropogenic activities may occur, has an impact on and may be affected by the environment where they are inserted, namely by the exchange of antimicrobial resistance genes. The latter may ultimately, through the food chain, represent a source of resistance genes to the human resistome. In an exploratory study of the presence of resistance genes in aquaculture sediments located in urban river estuaries, two machine learning models were applied to predict the source of 34 resistome observations in the aquaculture sediments of oysters and gilt-head sea bream, located in the estuaries of the Sado and Lima Rivers and in the Aveiro Lagoon, as well as in the sediments of the Tejo River estuary, where Japanese clams and mussels are collected. The first model included all 34 resistomes, amounting to 53 different antimicrobial resistance genes used as source predictors. The most important antimicrobial genes for source attribution were tetracycline resistance genes tet(51) and tet(L); aminoglycoside resistance gene aadA6; beta-lactam resistance gene blaBRO-2; and amphenicol resistance gene cmx_1. The second model included only oyster sediment resistomes, amounting to 30 antimicrobial resistance genes as predictors. The most important antimicrobial genes for source attribution were the aminoglycoside resistance gene aadA6, followed by the tetracycline genes tet(L) and tet(33). This exploratory study provides the first information about antimicrobial resistance genes in intensive and semi-intensive aquaculture in Portugal, helping to recognize the importance of environmental control to maintain the integrity and the sustainability of aquaculture farms.

Correlations between childhood maltreatment, anxiety and depressive symptoms, and risk behaviors in adolescent schoolchildren.

OBJECTIVE: Childhood maltreatment is extremely harmful to health, especially in relation to development of the psychiatric disorders throughout life. The objective of this study was to describe the prevalence and types of maltreatment in a sample of adolescent schoolchildren and to investigate associations between maltreatment types and anxiety and depressive symptoms, sociodemographic variables, and risk behaviors. The study also identified which variables were the greatest predictors of anxiety and depressive symptoms. METHODS: We conducted a cross-sectional study with a sample of 654 school students aged 11 to 17 years. We collected sociodemographic data and administered the Revised Child Anxiety and Depression Scale (RCADS-47) to measure anxiety and depressive symptoms as well as the Childhood Trauma Questionnaire (CTQ) to evaluate maltreatment and adverse experiences such as abuse and negligence during childhood and adolescence. Statistical analyses were conducted to estimate correlations between sociodemographic data, anxiety, depression, and types of maltreatment. A regression analysis was also conducted to identify maltreatment types that predict psychological symptoms. RESULTS: Emotional abuse and emotional neglect were the most prevalent types of maltreatment. Statistically, emotional abuse was the maltreatment type most strongly correlated with depression and anxiety and tended to co-occur with other types of maltreatment. Additionally, emotional and sexual abuse were the greatest predictors of anxiety and depression in adolescents. CONCLUSION: The above results reinforce the findings of previous studies in terms of understanding the effects of maltreatment. They identify emotional abuse as the main predictor of depressive and anxiety symptoms.

Correlations between childhood maltreatment, anxiety and depressive symptoms, and risk behaviors in adolescent schoolchildren

Abstract Objective Childhood maltreatment is extremely harmful to health, especially in relation to development of the psychiatric disorders throughout life. The objective of this study was to describe the prevalence and types of maltreatment in a sample of adolescent schoolchildren and to investigate associations between maltreatment types and anxiety and depressive symptoms, sociodemographic variables, and risk behaviors. The study also identified which variables were the greatest predictors of anxiety and depressive symptoms. Methods We conducted a cross-sectional study with a sample of 654 school students aged 11 to 17 years. We collected sociodemographic data and administered the Revised Child Anxiety and Depression Scale (RCADS-47) to measure anxiety and depressive symptoms as well as the Childhood Trauma Questionnaire (CTQ) to evaluate maltreatment and adverse experiences such as abuse and negligence during childhood and adolescence. Statistical analyses were conducted to estimate correlations between sociodemographic data, anxiety, depression, and types of maltreatment. A regression analysis was also conducted to identify maltreatment types that predict psychological symptoms. Results Emotional abuse and emotional neglect were the most prevalent types of maltreatment. Statistically, emotional abuse was the maltreatment type most strongly correlated with depression and anxiety and tended to co-occur with other types of maltreatment. Additionally, emotional and sexual abuse were the greatest predictors of anxiety and depression in adolescents. Conclusion The above results reinforce the findings of previous studies in terms of understanding the effects of maltreatment. They identify emotional abuse as the main predictor of depressive and anxiety symptoms.

RdJ detection tests to identify a unique MRSA clone of ST105-SCCmecII lineage and its variants disseminated in the metropolitan region of Rio de Janeiro.

Hospital bloodstream infection (BSI) caused by methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of morbidity and mortality and is frequently related to invasive procedures and medically complex patients. An important feature of MRSA is the clonal structure of its population. Specific MRSA clones may differ in their pathogenic, epidemiological, and antimicrobial resistance profiles. Whole-genome sequencing is currently the most robust and discriminatory technique for tracking hypervirulent/well-adapted MRSA clones. However, it remains an expensive and time-consuming technique that requires specialized personnel. In this work, we describe a pangenome protocol, based on binary matrix (1,0) of open reading frames (ORFs), that can be used to quickly find diagnostic, apomorphic sequence mutations that can serve as biomarkers. We use this technique to create a diagnostic screen for MRSA isolates circulating in the Rio de Janeiro metropolitan area, the RdJ clone, which is prevalent in BSI. The method described here has 100% specificity and sensitivity, eliminating the need to use genomic sequencing for clonal identification. The protocol used is relatively simple and all the steps, formulas and commands used are described in this work, such that this strategy can also be used to identify other MRSA clones and even clones from other bacterial species.

Intersectoral collaboration in a One Health approach: Lessons learned from a country-level simulation exercise.

Intersectoral collaboration is an essential component of the One Health (OH) approach, which recognises the interconnectedness of the health of humans, animals, and the environment. The OH European Joint Programme (OHEJP) developed a national foodborne outbreak table-top simulation exercise (SimEx) to practice OH capacity and interoperability across the public health, animal health, and food safety sectors, improving OH preparedness for future disease outbreaks. The Portuguese OHEJP SimEx highlighted strengths and weaknesses regarding the roles and functions of available systems, the constraints of existing legislation, the importance of harmonisation and data sharing, and the creation of common main messages adapted to each target sector. However, there is still a long way to go to ensure cooperation among the Public Health, Animal Health, and Food Safety sectors, as a OH approach relies not only on the awareness of "field experts" but also on political and organisational willingness and commitment.

Serum butyrylcholinesterase activity in healthy dogs with and without exposure to diazinon.

BACKGROUND: Cholinesterase is a biomarker for poisonings by anticholinesterase agents, but its reference values are scarce, and possible interaction with collars containing parasiticides has not been studied. OBJECTIVES: We aimed to evaluate the serum cholinesterase activity of healthy dogs without a history of contact with anticholinesterase agents and healthy animals exposed to commercial collars containing organophosphate. METHODS: Ninety-nine dogs were used and included healthy animals without recent exposure to anticholinesterase agents and healthy animals previously exposed to diazinon collars. Serum quantification of the enzyme butyrylcholinesterase (BuchE) through spectrophotometry was conducted on all samples. In experiment 1, BuchE activity was quantified at time 0 and 7 days after, a time when the samples were kept at -18°C. In experiment 2, sampling times were 0, 7, 14, 21, 28, and 56 days. RESULTS: Time 0 values were 4622.38 ± 1311.53 U/L. After 7 days, a significant decay was observed, with a mean of 3934.45 ± 1430.45 U/L. Spearman's test was performed, finding a weak correlation between ALT, creatinine, total plasma proteins, age, weight, red blood cells, platelets, leukocytes, and BuchE activities. In experiment 2, the mean at time 0 was 4753 ± 454.8 U/L. With exposure to the collar, there was a decay of up to 93% after 14 days. CONCLUSIONS: Normality values of serum BuchE in healthy dogs without a history of exposure to anticholinesterase agents were 4360.8-4883.96 U/L. Freezing serum caused a decrease in BuchE activity. Exposure to commercial collars containing diazinon also reduced BuchE activity without clinical signs, indicating that previously exposed animals should be evaluated carefully.

Investigation of antimicrobial susceptibility and genetic diversity among Staphylococcus pseudintermedius isolated from dogs in Rio de Janeiro.

Staphylococcus pseudintermedius is an opportunistic pathogen causing a variety of infections that are difficult to treat, especially because of the development of antimicrobial resistance. It has a clonal distribution around the world. To have a better understanding of the MRSP population, we search the presence of MRSP in colonized or infected dogs. Samples from 99 dogs with infections and 35 from asymptomatic dogs were collected. Isolates were identified by mass spectrometry and Multiplex-PCR. The mecA gene was confirmed by conventional PCR. MRSP strains were analyzed by whole-genome sequencing. 75 S. pseudintermedius were identified, most from infection cases. The species were isolated from 70 out of the 135 dogs. Penicillin and Trimethoprim/Sulfamethoxazole presented higher resistance rates. Forty-seven strains were classified as multi-drug resistant (MDR), and were more isolated from dogs with infection (P < 0.05). Eighteen samples were classified as MRSP, representing 24.0% of the population. Six of 16 MRSP sequenced samples belonged to the world spread clone ST71; others belonged to unknown clones. Most samples carried the SCCmec type IIIA. Twenty-one different genetic resistance determinants were found among MRPS strains. MRSP is circulating among infected and colonized dogs in Rio de Janeiro, Brazil.

The Health Status of Horses Used for at Least Six Complete Cycles of Loxoscelic Antivenom Production.

Antivenom production against Loxosceles venom relies on horses being immunized and bled for plasma harvest. One horse can partake in several cycles of antivenom production, which will require years of constant venom and adjuvant inoculation and bleeding. The actual impact on the health of horses that participate in several antivenom-producing cycles is unknown. Therefore, this study aimed to evaluate the general health status of horses that underwent at least six cycles of loxoscelic antivenom production. Seven crossbred horses that had partaken in six to eight complete antivenom-producing cycles were used and established as the immunized group (IG). Under the same handling and general management, eleven horses were established as the control group (CG). The horses were evaluated regarding their general clinical status and had their blood sampled, and an ECG recorded. The IG presented lower RBC and PCV, despite keeping values within inferior limits for the species. Renal function was not impaired, and liver-related enzymes were higher than those in the CG, probably due to liver exertion from immunoglobulin synthesis. ECG showed some abnormalities in the IG, such as atrioventricular block and a wandering atrial pacemaker, corroborated by an increase in CK-MB. The cardiovascular abnormalities were mainly found in the horses that participated in several antivenom-producing cycles. The overall results indicate that these horses had some impairment of their general health status. Once available, some alternative, less toxic antigens should replace the venom for immunization of horses used for antivenom production.

Collapse of scallop Nodipecten nodosus production in the tropical Southeast Brazil as a possible consequence of global warming and water pollution.

Mollusc rearing is a relevant global socioeconomic activity. However, this activity has faced severe problems in the last years in southeast Brazil. The mariculture scallop production dropped from 51,2 tons in 2016 to 10,2 tons in 2022 in the Baia da Ilha Grande (BIG; Rio de Janeiro). However, the possible causes of this collapse are unknown. This study aimed to analyze decadal trends of water quality in Nodipecten nodosus spat and adult production in BIG. We also performed physical-chemical and biological water quality analyses of three scallop farms and two nearby locations at BIG in 2022 to evaluate possible environmental stressors and risks. Scallop spat production dropped drastically in the last five years (2018-2022: mean ± stdev: 0.47 ± 0.45 million). Spat production was higher in colder waters and during peaks of Chlorophyll a in the last 13 years. Reduction of Chlorophyll a coincided with decreasing spat production in the last five years. Warmer periods (>27 °C) of the year may hamper scallop development. Counts of potentially pathogenic bacteria (Vibrios) and Escherichia coli were significantly higher in warmer periods which may further reduce scallop productivity. Shotgun metagenomics of seawater samples from the five studied corroborated these culture-based counts. Vibrios and fecal indicator bacteria metagenomic sequences were abundant across the entire study area throughout 2022. The results of this study suggest the collapse of scallop mariculture is the result of a synergistic negative effect of global warming and poor seawater quality.

Effects of coenzyme Q10 and N-acetylcysteine on experimental poisoning by paracetamol in Wistar rats.

Paracetamol (PAR) is a drug widely used in human and veterinary medicine as an analgesic and antipyretic, often involved in cases of intoxication. The most common clinical signs result from damage to red blood cells and hepatocytes, and this intoxication is considered a model for the induction of acute liver failure. In the present study, the hepatoprotective effects of coenzyme Q10 (CoQ10) and N-acetylcysteine (NAC) against experimental paracetamol (PAR) poisoning were analysed. Thirty-five adult Wistar rats (Rattus novergicus albinus) were randomly assigned to five groups, and thirty-one of these survived the treatments. Negative control group (CON-) received 1mL of 0.9% NaCl orally (PO). Other groups received 1.2g/kg of PAR (PO). Positive control group (CON+) received only PAR. NAC group received 800 mg/kg intraperitoneally (IP) of NAC 1h after the administration of PAR and at 12 h received 1mL of 0.9% NaCl, IP. The fourth group (CoQ10) received 1h and 12 h after intoxication, CoQ10 (10mg/kg IP). And the fifth group (NAC+CoQ10) received NAC (800mg/kg, IP) and CoQ10 (10mg/kg, IP). After 12 hours, the rats were euthanized and necropsied to collect liver and kidney tissues for histopathological evaluation and electronic microscopy. A single dose of PAR caused severe acute hepatitis. NAC couldn't reverse the liver and kidney damages. The group that received CoQ10 and NAC had moderate liver damage, while the group that received only CoQ10 had lower values of liver enzymes and mild liver and kidney damage. Animals that received treatment with CoQ10 or NAC+CoQ10 presented normal hepatocyte mitochondria and nuclei. Although CoQ10 couldn't reverse PAR organ damage, results indicate promising hepatoprotection in Wistar rats.

Editorial for Special Issue Foodborne Pathogens: Infections and Pathogenesis.

Foodborne microorganisms substantially impact food safety and contribute considerably to the public health and economic burden of infectious diseases worldwide [...].

Toxic plants from the perspective of a "Quilombola" community in the Cerrado region of Brazil.

A multi-disciplinary team surveyed ranchers at the Kalunga Historical and Cultural Heritage Site, in the Cerrado region of west central Brazil, to determine impacts promoted by toxic plants on cattle. The expedition to the Kalunga region was carried out by Brazilian and American researchers. Previously selected cattle ranch properties from "Vão das Almas", "Engenho II" and "Vão do Moleque" were visited. Twenty-four interviews were carried out with cattle ranchers and a questionnaire was applied to obtain information about outbreaks of native plant poisoning and their effects on livestock, and the use of local plants in phytotherapy. We classified problematic plants into three distinct categories. First, the toxic plants most cited by residents causing cattle losses were the flowers of Caryocar brasiliense Cambess ("pequi"), the fruits of Terminalia corrugata (Ducke) Gere & Boatwr. (Buchenavia tomentosa Eichler - "mirindiba" or "pau-pilão"), Eugenia dysenterica (Mart.) DC ("cagaita"), and Palicourea marcgravii A. St. Hil ("erva-café" or "cafezinho"). Secondly, other plants considered toxic, but causing less severe losses were Emmotum nitens (Benth.) Miers ("casco d'anta"), Indigofera lespedezioides (Kunth) ("timbozinho"), Ricinus communis L. ("mamona"), Pteridium esculentum (G. Forst.) Cockayne ("samambaia"), Stryphnodendron adstringens (Mart.) Coville ("barbatimão"), and Actinocladum verticillatum (Nees) McClure ex Soderstr. ("cambaúba"). The most important finding was the identification of the C. brasiliense flower as potentially toxic to cattle, which must be subject for future research. Further, we confirmed the toxicity and importance of P. marcgravii, E. dysenterica, and Terminalia corrugata. The survey highlighted phytotherapy plants used by the community, and greatly increased awareness by local livestock producers of poisonous plants for management purposes. We conclude that ethnobotanical knowledge, especially from the traditional community, is essential to understand livestock losses to toxic plants, and should be valued not only for reducing livestock losses, but also for cultural importance to the Kalunga communities in the Cerrado.

Brumadinho dam collapse induces changes in the microbiome and the antibiotic resistance of the Paraopeba River (Minas Gerais, Brazil).

The rupture of the Córrego do Feijão dam in Brumadinho (January 25, 2019) caused serious damage to the Paraopeba River and compromised the quality of its waters for human consumption. However, the possible effects of the dam collapse on the river microbiome and its antibiotic resistance profiles are unknown. The present study aims to analyse the possible shifts in microbial diversity and enhancement of antibiotic resistance in the Paraopeba River. To this end, two sampling campaigns (February and May 2019) were performed to obtain water across the entire Paraopeba River (eight sampling locations: Moeda, Brumadinho, Igarapé, Juatuba, Varginha, Angueretá, Retiro Baixo and Três Marias; ~464 km). This sampling scheme enabled determining the effects of the disaster on the river microbiome. Total DNA and microbial isolation were performed with these water samples. The 16S rRNA-based microbiome analyses (n = 24; 2.05 million 16S rRNA reads) showed changes in microbial diversity immediately after the disaster with the presence of metal-indicating bacteria (Acinetobacter, Bacillus, Novosphingobium, and Sediminibacterium). Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) identification of bacterial isolates (n = 170) also disclosed possible indicators of faecal contamination across the Paraopeba (Cloacibacterium, Bacteroides, Feaecalibacterium, Bifidobacterium, Citrobacter, Enterobacter, Enterococcus and Escherichia). Antibiotic resistance increased significantly to ampicillin, ampicillin/sulbactam, amoxicillin/clavulanate, ceftriaxone, and cefalotin among isolates obtained in May after the disaster. The effects of toxic mud on microbiomes were felt at all points sampled up to Anguereta. The ore mud may have exacerbated the growth of different antibiotic-resistant, metal-resistant, and faecal-indicating bacteria in the Paraopeba River.

Fast calculation of spectral optical properties and pigment content detection in human normal and pathological kidney.

A fast calculation method was used to obtain the spectral optical properties of human normal and pathological (chromophobe renal cell carcinoma) kidney tissues. Using total transmittance, total reflectance and collimated transmittance spectra acquired from ex vivo kidney samples, the spectral optical properties of both tissues, namely the absorption, the scattering and the reduced scattering coefficients, as well as the scattering anisotropy, dispersion and light penetration depth, were calculated between 200 and 1000 nm. Analysis of the mean absorption coefficient spectra of the kidney tissues showed that both contain melanin and lipofuscin, and that 83 % of the melanin in the normal kidney converts into lipofuscin in the pathological kidney.

Organizational Factors Determining Access to Reperfusion Therapies in Ischemic Stroke-Systematic Literature Review.

BACKGROUND: After onset of acute ischemic stroke (AIS), there is a limited time window for delivering acute reperfusion therapies (ART) aiming to restore normal brain circulation. Despite its unequivocal benefits, the proportion of AIS patients receiving both types of ART, thrombolysis and thrombectomy, remains very low. The organization of a stroke care pathway is one of the main factors that determine timely access to ART. The knowledge on organizational factors influencing access to ART is sparce. Hence, we sought to systematize the existing data on the type and frequency of pre-hospital and in-hospital organizational factors that determine timely access to ART in patients with AIS. METHODOLOGY: Literature review on the frequency and type of organizational factors that determine access to ART after AIS. Pubmed and Scopus databases were the primary source of data. OpenGrey and Google Scholar were used for searching grey literature. Study quality analysis was based on the Newcastle-Ottawa Scale. RESULTS: A total of 128 studies were included. The main pre-hospital factors associated with delay or access to ART were medical emergency activation practices, pre-notification routines, ambulance use and existence of local/regional-specific strategies to mitigate the impact of geographic distance between patient locations and Stroke Unit (SU). The most common intra-hospital factors studied were specific location of SU and brain imaging room within the hospital, and the existence and promotion of specific stroke treatment protocols. Most frequent factors associated with increased access ART were periodic public education, promotion of hospital pre-notification and specific pre- and intra-hospital stroke pathways. In specific urban areas, mobile stroke units were found to be valid options to increase timely access to ART. CONCLUSIONS: Implementation of different organizational factors and strategies can reduce time delays and increase the number of AIS patients receiving ART, with most of them being replicable in any context, and some in only very specific contexts.

Estuarine Aquacultures at the Crossroads of Animal Production and Antibacterial Resistance: A Metagenomic Approach to the Resistome.

It is recognized that the spread of antibiotic resistance (AR) genes among aquatic environments, including aquaculture and the human environment, can have detrimental effects on human and animal health and the ecosystem. Thus, when transmitted to the human microbiome or pathogens, resistance genes risk human health by compromising the eventual treatment of infections with antibiotic therapy. This study aimed to define the resistance profile of aquaculture farms and their potential risk for spreading. Twenty-four sediments from oyster and gilthead sea bream aquaculture farms located in three Portuguese river estuaries (17 sediments from Sado, 4 from Aveiro, and 3 from Lima) were studied by comparative metagenomic analysis. The computation of the diversity of genes conferring resistance per antibiotic class revealed a significant increase in aminoglycosides, beta-lactams, disinfectants, quinolones, and tetracyclines counts. In all geographic locations under study, the most diverse AR genes confer resistance to the macrolides, tetracyclines and oxazolidinones classes, all of which are medically important for human and animal therapies, as well as resistance to disinfectants. The diversity of mobile genetic elements correlated with the number of AR genes such as tetracyclines, suggesting that AR could be easily mobilized among bacterial genomes and microbiomes.