Jose Luis Balcazar

ICRA Catalan Institute for Water Research | ICRA · Water Quality

Although antibiotic resistance has become a major threat to human health worldwide, this phenomenon has been largely overlooked in studies in environmental settings. Aquatic environments may provide an ideal setting for the acquisition and dissemination of antibiotic resistance, because they are frequently impacted by anthropogenic activities. This...

Although antibiotic resistance represents a significant and growing public health concern, the contribution of bacteriophages (phages) to the mobilization of antibiotic resistance genes (ARGs) in the environment has not been extensively studied. Recent studies, however, suggest that phages play an important role in the acquisition, maintenance, and...

Viruses significantly influence local and global biogeochemical cycles and help bacteria to survive in different environments by encoding various auxiliary metabolic genes (AMGs) associated with energy acquisition, stress tolerance and degradation of xenobiotics. Here we studied whether bacterial (dsDNA) virus encoded AMGs are enriched in organochl...

A growing number of recent studies suggest that the contribution of phages to antibiotic resistance should not be underestimated. Here we describe their implications for public and environmental health, with a special emphasis on the mechanisms underlying phage-mediated horizontal gene transfer.

Antibiotic resistance has become a major health concern; thus, there is a growing interest in exploring the occurrence of antibiotic resistance genes (ARGs) in the environment as well as the factors that contribute to their emergence. Aquatic ecosystems provide an ideal setting for the acquisition and spread of ARGs due to the continuous pollution...

Here, we report the draft genome sequence of Methyloversatilis sp. NSM2, isolated from a wastewater treatment plant. This strain was enriched using methane as the sole carbon source. The 4.5-Mb genome, with a GC content of 66.5%, provides valuable insights into the strain’s ecological role and metabolic capabilities.

As the most abundant living entities in the environment, viruses have been well recognized as crucial members in sustaining biogeochemical cycling. However, the significance of viruses in soil ecosystem multifunctionality remains under-explored. In this study, we used metagenomics and meta-viromics analysis to investigate the role of soil viruses i...

This study aimed to explore the abundance and diversity of antibiotic resistance genes (ARGs) in seahorses (Hippocampus barbouri and Hippocampus comes) and their surrounding environment. The combination of shotgun metagenomics and bioinformatics demonstrated a higher abundance of ARGs in seahorse-associated microbiomes, particularly in skin and gut...

Soils are not exempt from anthropogenic pollution, which can eventually cause disturbance of the microbial communities and areas without any kind of productivity. Among soil microbiota, bacteria play an important role in pollutant degradation, enabling them to thrive in contaminated sites. Given this, several techniques have been used to increase t...

Antimicrobial resistance (AMR) poses a major threat to global public health. Despite substantial efforts and progress, several key questions remain unanswered, especially regarding its spread in environmental settings. Health authorities globally face significant challenges in managing this threat, including the lack of consensus on universal micro...

Gaining insight into the diversity, structure, and metabolic functions of microbial communities is essential for understanding their roles in host health and ecosystem dynamics. However, research on the seahorse-associated microbiome remains limited, despite these threatened fish facing increasing human pressures worldwide. Here, we explored the mi...

The overuse and misuse of antibiotics have accelerated the selection of antibiotic-resistant bacteria, significantly impacting human, animal, and environmental health. As aquatic environments are vulnerable to antibiotic resistance, suitable management practices should be adopted to tackle this phenomenon. Here we show an effective, nature-based so...

This study aimed to investigate the taxonomic and functional patterns of the microbiome associated with Barbour’s seahorse (Hippocampus barbouri) using a combination of shotgun metagenomics and bioinformatics. The analyses revealed that Pseudomonadota and Bacillota were the dominant phyla in the seahorse skin microbiome, whereas Pseudomonadota and,...

Graphene oxide (GO) addition to anaerobic digestion has been suggested to enhance direct electron transfer. The impact of GO (0.075 g GO g−1 VS) and biologically and hydrothermally reduced GO (bio-rGO and h-rGO, respectively) on the methane production kinetics and removal of 12 pharmaceuticals was assessed in Fed-batch reactors. A decrease of 15 %...

In this opinion, we discuss the role of tRNAs in phage biology and their importance in DNA replication and phage‐host interactions. Phages are a diverse group of obligate bacterial viruses that possess genomes with a wide range of sizes. Among them, we find phages with few genes that depend entirely on their host's translational machinery for repli...

In this study, we present the complete annotated genome of a novel Salmonella phage, vB_SenS_ST1UNAM. This phage exhibits lytic activity against several Salmonella enterica serotypes, such as S. Typhi, S. Enteritidis, and S. Typhimurium strains, which are major causes of foodborne illness worldwide. Its genome consists of a linear, double-stranded...

The discharge of untreated or partially treated wastewater can have detrimental impacts on the quality of water bodies, posing a significant threat to public health and the environment. In Ecuador, previous research indicates a high prevalence of antimicrobial resistant (AMR) bacteria in surface waters affected by human activities, including irriga...

This study aimed to explore the microbial diversity and metabolic functions of the skin and gut of the tiger tail seahorse (Hippocampus comes) and their surrounding environment using shotgun metagenomics and bioinformatics. Members belonging to the Pseudomonadota phylum were dominant on the skin, whereas Bacteroidota was dominant in the gut. Bacill...

PUNTOS CLAVE • La acuicultura ha experimentado un desarrollo importante a nivel mundial, generando con su crecimiento e intensificación un incremento en la aparición de enfermedades provocadas principalmente por agentes bacterianos, las cuales han sido controladas mediante el uso de antibióticos. • La aplicación de estos compuestos antibióticos...

PUNTOS CLAVE • La optimización de los cultivos acuícolas se puede obtener mediante diferentes estrategias de control biológico, como son los probióticos, prebióticos o posbióticos. • Estas estrategias son capaces de restaurar una microbiota alterada por el uso de antibióticos o por los propios factores estresantes asociados a la producción acuíco...

This work aims to determine the occurrence, hazard and prioritization of pharmaceuticals from hospital wastewater in Costa Rica through the monitoring of 70 compounds and assessing their environmental risk through a hazard quotient approach (HQ). Moreover, the quantification of selected antibiotic resistance genes (ARGs) was conducted for the first...

Organic fertilizer microbiomes play substantial roles in soil ecological functions, including improving soil structure, crop yield, and pollutant dissipation. However, limited information is available about the ecological functions of phages and phage-encoded auxiliary metabolic genes (AMGs) in orga9nic fertilizers. Here we used a combination of me...

The addition of conductive materials to the anaerobic digestion bioreactor was suggested to enhance microbial activity. In the present work, an anaerobic membrane bioreactor treating municipal wastewater was operated for 385 days. The impact of different graphene oxide concentrations on the removal target pharmaceuticals and microbial community dyn...

In this study, taxonomic classification of intestinal microbiota from healthy Barbour’s seahorses (Hippocampus barbouri) was determined as it plays an important role in host nutrition and immunity. Genomic DNA was extracted from the intestinal mucus samples of eleven Barbour’s seahorses, which were subjected to high-throughput sequencing of bacteri...

The earthworm gut virome influences the structure and function of the gut microbiome, which in turn influences worm health and ecological functions. However, despite its ecological and soil quality implications, it remains elusive how earthworm intestinal phages respond to different environmental stress, such as soil pollution. Here we used metagen...

Although several studies have described the bacterial community composition associated with marine fish, there is limited information related to seahorses. Moreover, previous studies have demonstrated that the skin microbiota is useful for determining health status and common disorders in the host. This study, therefore, aimed to explore the skin b...

The effect of graphene oxide on the anaerobic digestion of waste activated sludge was investigated at two graphene oxide concentrations (0.025 and 0.075 g graphene oxide per g volatile solids) using biochemical methane potential tests. The occurrence of 36 pharmaceuticals was monitored in the solid and liquid phases before and after the anaerobic t...

The ecological drivers that direct the assembly of viral and host bacterial communities are largely unknown, even though viral-encoded accessory genes help host bacteria survive in polluted environments. To understand the ecological mechanism(s) of viruses and hosts synergistically surviving under organochlorine pesticide (OCP) stress, we investiga...

Antibiotic misuse in livestock is a major threat to human health, as bacteria are quickly developing resistance to them. We performed a comparative analysis of 25 faecal metagenomes from swine, poultry, cattle, and humans to investigate their resistance profiles. Our analysis revealed that all genes conferring resistance to antibiotic classes asses...

Bacterial viruses are the most abundant biological entities in soil ecosystems. Owing to the advent of metagenomics and viromics approaches, an ever‐increasing diversity of virus‐encoded auxiliary metabolic genes (AMGs) have been identified in soils, including those involved in the transformation of carbon, phosphorus, and sulfur, degradation of or...

The protective effects of a phage cocktail composed of vB_Vc_SrVc2 and vB_Vc_SrVc9 were tested in Pacific white shrimp (Litopenaeus vannamei) postlarvae, which were originally isolated from diseased shrimps and selected due to their broad-host-range properties against several pathogenic Vibrio species. We used culture-dependent and culture-independ...

This study investigates the occurrence, transport, and risks associated to antibiotic residues, antibiotic resistance genes (ARGs) and antibiotic resistant Escherichia coli (AR-E. coli) in eleven natural springs in an agroecosystem environment with intense livestock production, where groundwater nitrate concentration usually sets above 50 mg L⁻¹. O...

The intensification and diversification of production systems have increased the incidence of diseases, which are usually treated with antibiotics. However, its use should be restricted due to the increasing prevalence of antibiotic-resistant bacteria. Probiotics represent therefore an alternative environmentally friendly strategy for improving gro...

In this study, the frequency of canines infected with Leishmania spp. in an area endemic to leishmaniasis in humans was determined. A descriptive pilot study was conducted between the months of October and December 2020 on dogs from Rota, a community in the municipality of León, which included 45 specimens from the peridomestic area. Different vari...

One hundred and five uropathogenic Escherichia coli (UPEC) strains from patients with community-acquired urinary tract infection were characterized according to their phylogenetic groups, virulence factors, serogroups, antibiotics resistance, and genotype. The pathogenic phylogenetic groups (B2, D, and F) were found in 71.4% of the tested strains....

Rhipicephalus (Boophilus) microplus has a strong impact on bovine health. The aim of this study was to evaluate the in vitro acaricidal activity of Piper tuberculatum extracts on R. (Boophilus) microplus ticks obtained from cattle. The adult immersion test (AIT) was used to estimate the inhibition of oviposition. Moreover, the larval package test (...

In this study, the genomes of two lytic bacteriophages, vB_EcoS-phiEc3 and vB_EcoS-phiEc4, were sequenced and characterized using bioinformatics approaches. Whole-genome analysis showed that both phages belonged to the Kagunavirus genus, Guernseyvirinae subfamily and Siphoviridae family. Moreover, their genomes had 45, 288 bp and 44,540 bp, and G +...

Oxidative chemicals, such as nitrate, are periodically added to sewer systems to mitigate sulfide production and its accumulation but data are lacking on how these treatments affect sewage microbiota and alter their gene expression and mobilization. The present study investigated such effects on the biofilm of a full-scale sewer collected at two di...

This study aimed to explore the effect of a bacteriophage cocktail, pyophage, on the treatment of wastewater containing antibiotics in an anaerobic membrane bioreactor (AnMBR). During the operational period, performance of the AnMBR was monitored through the changes in chemical oxygen demand (COD), antibiotic removal, transmembrane pressure, and bi...

In the present paper, the mesophilic (35 °C) and thermophilic (55 °C) biomethanization of poultry and cattle manures were investigated using biochemical methane potential (BMP) tests. Specific methane production (SMP), 24 pharmaceutical compounds (PhACs), and five antibiotic resistance genes (ARGs) (blaKPC, ermB, qnrS, sul1 and tetW) together with...

Because the skin microbiota is valuable for elucidating health status and common disorders in the host, this study aimed to describe the bacterial community composition of the skin of Barbour’s seahorse ( Hippocampus barbouri ) using high-throughput sequencing of 16S ribosomal RNA genes. Water and sediment samples from the surrounding environment w...

Although phage therapy is still in the research and development stage, there are already a small number of cases where phages have been successfully used as an alternative treatment for multidrug-resistant infections. Given this, this Commentary discusses the potential contribution of phage therapy to combat urinary tract infections.

In this study, taxonomic classification of intestinal microbiota from healthy Barbour’s seahorses ( Hippocampus barbouri ) was determined as it plays an important role in host nutrition and immunity. Genomic DNA was extracted from the intestinal mucus samples of eleven Barbour’s seahorses, which were subjected to high-throughput sequencing of bacte...

In this study, taxonomic classification of intestinal microbiota from healthy Barbour’s seahorses ( Hippocampus barbouri ) was determined as it plays an important role in host nutrition and immunity. Genomic DNA was extracted from the intestinal mucus samples of eleven Barbour’s seahorses, which were subjected to high-throughput sequencing of bacte...

This study aimed to identify and characterize integrons among multidrug-resistant (MDR) uropathogenic Escherichia coli (UPEC) from outpatients in Mexico City, Mexico. PCR assays were used to screen for the presence of class 1, 2 and 3 integrons, whose PCR products were sequenced to identify the inserted gene cassettes within the variable regions. O...

Shrimp farming has experienced rising costs as a result of disease outbreaks associated with Vibrio spp. Suitable strategies for disease prevention and control are therefore urgently needed. This study aimed to evaluate the antimicrobial effect of Moringa oleifera seed powder against Vibrio cholerae in the rearing water of Pacific white shrimp (Pen...

In this study, we present the complete, annotated genome of a new member of the Tequatrovirus (T4-like) genus, Escherichia phage vB_EcoM_C2-3. This phage has an isometric head (92 nm in diameter) and a contractile tail (114 nm in length). Its genome consists of a linear, double-stranded DNA of 167,069 bp with an average G+C content of 35.3%. There...

The effect of anaerobic treatment of swine manure at 35 °C (mesophilic) and 55 °C (thermophilic) on methane production, microbial community and contaminants of emerging concern was investigated. Pasteurization pretreatment and post treatment was also investigated in combination with anaerobic treatment at 35 °C. Specific methane production (SMP), 2...

This article considers current trends in antimicrobial resistance (AMR) research and knowledge gaps relevant to policymaking in the water sector. Specifically, biological indicators of AMR (antibiotic-resistant bacteria and their resistance genes) and detection methods that have been used so far are identified and discussed, as well as the problems...

Background The black spiny‐tailed iguana (Ctenosaura similis) is an endemic animal in Mesoamerica, whose meat is consumed by the local population. Objectives Because the black spiny‐tailed iguana may be potential reservoirs of pathogens, this study aimed to isolate and characterise Salmonella spp. in their meat commercialised in markets of the cit...

The aim of this study was to identify pathogenic bacteria in fishes from 4 communities on the western Pacific coast of Nicaragua. A total of 62 fishes were collected for microbiological analysis using muscle samples, which were inoculated on thiosulfate-citrate-bile salts-sucrose agar and trypticase soy agar. Bacterial identification was carried ou...

Although anthropogenic activities contribute to the selection and spread of antibiotic resistance in aquatic environments, limited information is available from countries with absent or incomplete sewage treatment systems and the impact of their discharges onto water bodies. This study therefore aimed to characterize the genetic structure of colist...

Urinary tract infections (UTIs) are mainly caused by uropathogenic Escherichia coli (UPEC), whose impact can be exacerbated by multidrug-resistant (MDR) strains. Effective control strategies are, therefore, urgently needed. Among them, phage therapy represents a suitable alternative. Here, we describe the isolation and characterization of novel pha...

The anaerobic treatment of municipal wastewater (WW) results in low biogas production due to its relatively low concentration of organic matter. To overcome this problem, this paper assesses the potential of combining forward osmosis (FO), as a pre-treatment to concentrate real municipal WW with anaerobic digestion (AD), with the aim of enhancing m...

This study investigates the effect of psychrophilic, mesophilic and thermophilic temperatures on the anaerobic treatment of slaughterhouse wastewater, in terms of biogas production, occurrence of 30 pharmaceutical compounds of veterinary use, 4 antibiotic resistance genes (ARGs) which provide resistance to tetracyclines (tetW), fluoroquinolones (qn...

This study identified the bacterial community composition associated with Barbour’s seahorses (Hippocampus barbouri). Seahorses and samples from the surrounding environment (sediment and water) were collected from Cantiasay Island in Surigao del Norte, Philippines. Genomic DNA was isolated from these samples, and the V1‐V3 region of the 16S rRNA ge...

The Seriola genus includes species of worldwide commercial importance due to its rapid growth and easy adaptability to confinement conditions. However, like other fish species, large mortalities occur during their early life stages, where the main problems are caused by opportunistic bacteria. Disease control strategies are thus urgently needed. Th...

In developing countries, where high levels of antimicrobial resistance are observed in hospitals, the surveillance of this phenomenon in wastewater treatment plants (WWTPs) and the environment is very limited, especially using cutting-edge culture-independent methods. In this study, the composition of bacterial communities, the resistome and mobilo...

This article focuses on how bacteriophages (phages), antibiotic-resistance genes (ARGs), and disinfection practices intersect. Phages are considered to be the most abundant biological entities on Earth and they have the potential to transfer genes (including ARGs) among their bacterial hosts. In the urban water cycle, phages are used as indicators...

Although bacteriophages (or simply phages) are the most abundant biological entities and have the potential to transfer genetic material between bacterial hosts, their contribution to the acquisition and spread of antibiotic resistance genes in the environment has not been extensively studied. The environment is continually exposed to a wide variet...

The World Health Organization Global Action Plan recommends integrated surveillance programs as crucial strategies for monitoring antibiotic resistance. Although several national surveillance programs are in place for clinical and veterinary settings, no such schemes exist for monitoring antibiotic-resistant bacteria in the environment. In this tra...

Objective: This study was aimed to assess the effect of a novel postbiotic on bacterial community composition and structure within the intestinal ecosystem of rainbow trout (Oncorhynchus mykiss), as well as evaluate its capacity to protect rainbow trout from Lactococcus garvieae infection. Results: After 30 days of dietary postbiotic supplementati...

This study aimed to evaluate the effect of rice bran fermented with a consortium of Bacillus and Lysinibacillus strains (RB + BLb) on the bacterial community structure and composition in the gastrointestinal tract of Pacific white shrimp (Penaeus vannamei), as well as its effect on growth performance and health status. Rice bran fermented with a co...

Background: Wastewater treatment plants (WWTPs) are microbial factories aimed to reduce the amount of nutrients and pathogenic microorganisms in the treated wastewater before its discharge into the environment. We studied the impact of urban WWTP effluents on the abundance of antibiotic resistance genes (ARGs) and antibiotic-resistant Escherichia...

Introducción. En países en vía de desarrollo donde se observan altos niveles de resistencia bacteriana en hospitales‚ la vigilancia de la resistencia en el ambiente y plantas de tratamiento de agua residual (PTARs) es poca y menos empleando enfoques metagenómicos. En este estudio se determinó la composición las comunidades bacterianas y la ocurrenc...

The dosage of free nitrous acid (FNA) is an effective treatment to control emissions of hydrogen sulfide and methane from sewers. It is unclear, however, whether its application could affect the sewer resistome and mobilome (the pool of antibiotic resistance genes (ARGs) and mobile genetic elements (MGEs), respectively). Here, a lab-scale assay for...

The COVID-19 pandemic has severely impacted public health and the worldwide economy. Converging evidence from the current pandemic, previous outbreaks and controlled experiments indicates that SARS-CoVs are present in wastewater for several days, leading to potential health risks via waterborne and aerosolized wastewater pathways. Conventional wast...

Growing global concerns about antibiotic resistance have generated a considerable interest in the search for alternative environmental-friendly approaches. This study was aimed to assess the antimicrobial activity of a multi-citrus extract-based feed additive (Biocitro®) against some fish pathogens, as well as evaluate its capacity to protect rainb...

Aims: This study describes the effect of phage therapy on hatching of longfin yellowtail (Seriola rivoliana) eggs challenged with Photobacterium damselae subsp. damselae. Methods and results: A lytic phage (vB_Pd_PDCC-1) against P. damselae subsp. damselae was isolated and characterized. The use of phage vB_Pd_PDCC-1 increased the hatching rate...