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Microorganisms May 2024This study extensively analyzed the bacterial information of biofilms and activated sludge in oxic reactors of full-scale moving bed biofilm reactor-integrated...
This study extensively analyzed the bacterial information of biofilms and activated sludge in oxic reactors of full-scale moving bed biofilm reactor-integrated fixed-film activated sludge (MBBR-IFAS) systems. The bacterial communities of biofilms and activated sludge differed statistically (R = 0.624, < 0.01). The denitrifying genera , , , and were more abundant in activated sludge ( < 0.05), while comammox was more abundant in biofilms ( < 0.05), with an average relative abundance of 8.13%. and had weak co-occurrence relationships with other genera in the MBBR-IFAS systems. Potential function analysis revealed no differences in pathways at levels 1 and 2 based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) between biofilms and activated sludge. However, in terms of pathways at level 3, biofilms had more potential in 26 pathways, including various organic biodegradation and membrane and signal transportation pathways. In comparison, activated sludge had more potential in only five pathways, including glycan biosynthesis and metabolism. With respect to nitrogen metabolism, biofilms had greater potential for nitrification (ammonia oxidation) (M00528), and complete nitrification (comammox) (M00804) concretely accounted for methane/ammonia monooxygenase (K10944, K10945, and K10946) and hydroxylamine dehydrogenase (K10535). This study provides a theoretical basis for MBBR-IFAS systems from the perspective of microorganisms.
PubMed: 38930504
DOI: 10.3390/microorganisms12061121 -
Microbial Pathogenesis Jun 2024Arcobacter butzleri is a foodborne pathogen that mainly causes enteritis in humans, but the number of cases of bacteraemia has increased in recent years. However, there...
Arcobacter butzleri is a foodborne pathogen that mainly causes enteritis in humans, but the number of cases of bacteraemia has increased in recent years. However, there is still limited knowledge on the pathogenic mechanisms of this bacterium. To investigate how A. butzleri causes disease, single knockout mutants were constructed in the cadF, ABU_RS00335, ciaB, and flaAB genes, which might be involved in adhesion and invasion properties. These mutants and the isogenic wild-type (WT) were then tested for their ability to adhere and invade human Caco-2 and HT29-MTX cells. The adhesion and invasion of A. butzleri RM4018 strain was also visualized by a Leica CTR 6500 confocal microscope. The adhesion and invasion abilities of mutants lacking the invasion antigen CiaB or a functional flagellum were lower than those of the WTs. However, the extent of the decrease varied depending on the strain and/or cell line. Mutants lacking the fibronectin (FN)-binding protein CadF consistently exhibited reduced abilities, while the inactivation of the other studied FN-binding protein, ABU_RS00335, led to a reduction in only one of the two strains tested. Therefore, the ciaB and flaAB genes appear to be important for A. butzleri adhesion and invasion properties, while cadF appears to be indispensable.
PubMed: 38880315
DOI: 10.1016/j.micpath.2024.106752 -
Engineering in Life Sciences Jun 2024Microplastics (MPs) are major concern due to their potential harm to ecosystems and most research has focused on their presence and fate, with limited attention to their...
Microplastics (MPs) are major concern due to their potential harm to ecosystems and most research has focused on their presence and fate, with limited attention to their biodegradation in aquatic ecosystems. Nevertheless, MPs act as hotspots for the colonization by a diverse range of microorganisms that can adhere to plastic surfaces, resulting in the subsequent formation of biofilms-a potential threat especially in terms of pathogenicity. This study employed 16S rRNA and 18S rRNA sequencing metagenomic analyses to investigate microbial communities within biofilms on plastic materials exposed to long-term marine and freshwater environments. Three species , , and emerged as dominant species in M_MP sample, while was the predominant species within the F_MP sample. The 18S rRNA sequencing revealed the presence of the fungal phylum and the microalgal species in F_MP. Although, the primary species detected on M_MP and F_MP samples include bacteria previously implicated as pathogen, the predominant species identified in this study were unconnected to MP-associated biofilms or MP degradation. Their presence constitutes a novel discovery, opening promising avenues for the exploration of their potential involvement in the biodegradation of MPs within aquatic environments.
PubMed: 38845816
DOI: 10.1002/elsc.202300249 -
Le Infezioni in Medicina 2024(formerly ), is a newly recognized like emerging foodborne pathogen worldwide, usually causing gastrointestinal symptoms in young children. A 4-year-old boy was...
(formerly ), is a newly recognized like emerging foodborne pathogen worldwide, usually causing gastrointestinal symptoms in young children. A 4-year-old boy was admitted to the Department of Pediatrics, University Hospital of Split, Croatia, because of malnutrition, lost appetite and prolonged watery diarrhea. A comprehensive diagnostics, including biochemistry, haematology, allergology, microbiology and radiology, were performed. The only positive microbiology result was unexpected isolation of on selective media for , after 48 hours of incubation on 42°C, among microaerophilic atmosphere. Clinical course was favorable and after symptomatic therapy child was discharged in good clinical condition and normal peristalsis to home care, with the recommendation of taking high-protein preparations to improve nutritional status. In addition, we performed a literature review of clinical cases caused by infection. The first report of isolated from stool sample in a 4-year old boy in Croatia, along with other clinical reports in literature, highlights the importance of standardisation and improvement of microbiological analysis, especially implementation of new methods for the identification of emerging pathogens.
PubMed: 38827827
DOI: 10.53854/liim-3202-12 -
PloS One 2024Due to the dramatic reduction of sea cucumber Isostichopus badionotus populations in the Yucatan Peninsula by overfishing and poaching, aquaculture has been encouraged...
Due to the dramatic reduction of sea cucumber Isostichopus badionotus populations in the Yucatan Peninsula by overfishing and poaching, aquaculture has been encouraged as an alternative to commercial catching and restoring wild populations. However, the scarcity of broodstock, the emergence of a new disease in the auricularia larvae stage, and the development of skin ulceration syndrome (SUS) in the culture have limited aquaculture development. This study presents the changes in the intestine and skin microbiota observed in early and advanced stages of SUS disease in cultured juvenile I. badionotus obtained during an outbreak in experimental culture through 16S rRNA gene sequencing and histological evidence. Our results showed inflammation in the intestines of juveniles at both stages of SUS. However, more severe tissue damage and the presence of bacterial clusters were detected only in the advanced stages of SUS. Differences in the composition and structure of the intestinal and skin bacterial community from early and advanced stages of SUS were detected, with more evident changes in the intestinal microbial communities. These findings suggest that SUS was not induced by a single pathogenic bacterium. Nevertheless, a decrease in the abundance of Vibrio and an increase in Halarcobacter (syn. Arcobacter) was observed, suggesting that these two bacterial groups could be keystone genera involved in SUS disease.
Topics: Animals; Microbiota; Skin; Sea Cucumbers; Aquaculture; RNA, Ribosomal, 16S; Skin Ulcer; Disease Outbreaks; Gastrointestinal Microbiome
PubMed: 38820441
DOI: 10.1371/journal.pone.0303480 -
FEMS Microbiology Ecology May 2024Wastewater treatment plants (WWTPs) provide a suitable environment for the interaction of antibiotic resistant bacteria and antibiotic-resistance genes (ARGs) from...
Wastewater treatment plants (WWTPs) provide a suitable environment for the interaction of antibiotic resistant bacteria and antibiotic-resistance genes (ARGs) from human, animal, and environmental sources. The aim was to study the influent and effluent of two WWTPs in Croatia to identify bacterial hosts of clinically important beta-lactamase genes (blaTEM, blaVIM, blaOXA-48-like) and observe how their composition changes during the treatment process. A culture-independent epicPCR (Emulsion, Paired isolation and Concatenation Polymerase Chain Reaction) was used to identify the ARG hosts, and 16S rRNA amplicon sequencing to study the entire bacterial community. Different wastewater sources contributed to the significant differences in bacterial composition of the wastewater between the two WWTPs studied. A total of 167 genera were detected by epicPCR, with the Arcobacter genus, in which all ARGs studied were present, dominating in both WWTPs. In addition, the clinically important genera Acinetobacter and Aeromonas contained all ARGs examined. The blaOXA-48-like gene had the highest number of hosts, followed by blaVIM, while blaTEM had the narrowest host range. Based on 16S rRNA gene sequencing, ARG hosts were detected in both abundant and rare taxa. The number of hosts carrying investigated ARGs was reduced by wastewater treatment. EpicPCR provided valuable insights into the bacterial hosts of horizontally transmissible beta-lactamase genes in Croatian wastewater.
Topics: beta-Lactamases; Wastewater; Croatia; RNA, Ribosomal, 16S; Bacteria; Genes, Bacterial; Humans; DNA, Bacterial; Polymerase Chain Reaction; Drug Resistance, Bacterial
PubMed: 38796694
DOI: 10.1093/femsec/fiae081 -
Microorganisms Apr 2024In contrast to "frank" pathogens, like , , and , that always have a probability of disease, "opportunistic" pathogens are organisms that cause an infectious disease in a... (Review)
Review
In contrast to "frank" pathogens, like , , and , that always have a probability of disease, "opportunistic" pathogens are organisms that cause an infectious disease in a host with a weakened immune system and rarely in a healthy host. Historically, drinking water treatment has focused on control of frank pathogens, particularly those from human or animal sources (like , , or ), but in recent years outbreaks from drinking water have increasingly been due to opportunistic pathogens. Characteristics of opportunistic pathogens that make them problematic for water treatment include: (1) they are normally present in aquatic environments, (2) they grow in biofilms that protect the bacteria from disinfectants, and (3) under appropriate conditions in drinking water systems (e.g., warm water, stagnation, low disinfectant levels, etc.), these bacteria can amplify to levels that can pose a public health risk. The three most common opportunistic pathogens in drinking water systems are , , and . This report focuses on these organisms to provide information on their public health risk, occurrence in drinking water systems, susceptibility to various disinfectants, and other operational practices (like flushing and cleaning of pipes and storage tanks). In addition, information is provided on a group of nine other opportunistic pathogens that are less commonly found in drinking water systems, including , , , , , , , and several free-living amoebae including and species of The public health risk for these microbes in drinking water is still unclear, but in most cases, efforts to manage , mycobacteria, and risks will also be effective for these other opportunistic pathogens. The approach to managing opportunistic pathogens in drinking water supplies focuses on controlling the growth of these organisms. Many of these microbes are normal inhabitants in biofilms in water, so the attention is less on eliminating these organisms from entering the system and more on managing their occurrence and concentrations in the pipe network. With anticipated warming trends associated with climate change, the factors that drive the growth of opportunistic pathogens in drinking water systems will likely increase. It is important, therefore, to evaluate treatment barriers and management activities for control of opportunistic pathogen risks. Controls for primary treatment, particularly for turbidity management and disinfection, should be reviewed to ensure adequacy for opportunistic pathogen control. However, the major focus for the utility's opportunistic pathogen risk reduction plan is the management of biological activity and biofilms in the distribution system. Factors that influence the growth of microbes (primarily in biofilms) in the distribution system include, temperature, disinfectant type and concentration, nutrient levels (measured as AOC or BDOC), stagnation, flushing of pipes and cleaning of storage tank sediments, and corrosion control. Pressure management and distribution system integrity are also important to the microbial quality of water but are related more to the intrusion of contaminants into the distribution system rather than directly related to microbial growth. Summarizing the identified risk from drinking water, the availability and quality of disinfection data for treatment, and guidelines or standards for control showed that adequate information is best available for management of . For , the risk for this organism has been clearly established from drinking water, cases have increased worldwide, and it is one of the most identified causes of drinking water outbreaks. Water management best practices (e.g., maintenance of a disinfectant residual throughout the distribution system, flushing and cleaning of sediments in pipelines and storage tanks, among others) have been shown to be effective for control of in water supplies. In addition, there are well documented management guidelines available for the control of the organism in drinking water distribution systems. By comparison, management of risks for from water are less clear than for . Treatment of is difficult due to its resistance to disinfection, the tendency to form clumps, and attachment to surfaces in biofilms. Additionally, there are no guidelines for management of in drinking water, and one risk assessment study suggested a low risk of infection. The role of tap water in the transmission of the other opportunistic pathogens is less clear and, in many cases, actions to manage (e.g., maintenance of a disinfectant residual, flushing, cleaning of storage tanks, etc.) will also be beneficial in helping to manage these organisms as well.
PubMed: 38792751
DOI: 10.3390/microorganisms12050916 -
The Science of the Total Environment Jul 2024The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in humans, animals and environment is a growing threat to public health....
Characterisation of microbial communities and quantification of antibiotic resistance genes in Italian wastewater treatment plants using 16S rRNA sequencing and digital PCR.
The spread of antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in humans, animals and environment is a growing threat to public health. Wastewater treatment plants (WWTPs) are crucial in mitigating the risk of environmental contamination by effectively removing contaminants before discharge. However, the persistence of ARB and ARGs even after treatment is a challenge for the management of water system. To comprehensively assess antimicrobial resistance dynamics, we conducted a one-year monitoring study in three WWTPs in central Italy, both influents and effluents. We used seasonal sampling to analyze microbial communities by 16S rRNA, as well as to determine the prevalence and behaviour of major ARGs (sul1, tetA, bla, bla, bla, bla) and the class 1 Integron (int1). Predominant genera included in order: Arcobacter, Acinetobacter, Flavobacterium, Pseudarcobacter, Bacteroides, Aeromonas, Trichococcus, Cloacibacterium, Pseudomonas and Streptococcus. A higher diversity of bacterial communities was observed in the effluents compared to the influents. Within these communities, we also identified bacteria that may be associated with antibiotic resistance and pose a significant threat to human health. The mean concentrations (in gene copies per liter, gc/L) of ARGs and int1 in untreated wastewater (absolute abundance) were as follows: sul1 (4.1 × 10), tetA (5.2 × 10), bla (1.1 × 10), bla (2.1 × 10), bla (1.1 × 10), bla (9.4 × 10), and int1 (5.5 × 10). The mean values in treated effluents showed reductions ranging from one to three log. However, after normalizing to the 16S rRNA gene (relative abundance), it was observed that in 37.5 % (42/112) of measurements, the relative abundance of ARGs increased in effluents compared to influents. Furthermore, correlations were identified between ARGs and bacterial genera including priority pathogens. This study improves our understanding of the dynamics of ARGs and provides insights to develop more effective strategies to reduce their spread, protecting public health and preserving the future efficacy of antibiotics.
Topics: Wastewater; Italy; RNA, Ribosomal, 16S; Waste Disposal, Fluid; Bacteria; Drug Resistance, Microbial; Microbiota; Genes, Bacterial; Environmental Monitoring; Polymerase Chain Reaction; Drug Resistance, Bacterial; Anti-Bacterial Agents; Water Microbiology
PubMed: 38750766
DOI: 10.1016/j.scitotenv.2024.173217 -
Animals : An Open Access Journal From... Apr 2024Yaks are the main pillar of plateau animal husbandry and the material basis of local herdsmen's survival. The level of mineral elements in the body is closely related to...
Microbial Metagenomes and Host Transcriptomes Reveal the Dynamic Changes of Rumen Gene Expression, Microbial Colonization and Co-Regulation of Mineral Element Metabolism in Yaks from Birth to Adulthood.
Yaks are the main pillar of plateau animal husbandry and the material basis of local herdsmen's survival. The level of mineral elements in the body is closely related to the production performance of yaks. In this study, we performed a comprehensive analysis of rumen epithelial morphology, transcriptomics and metagenomics to explore the dynamics of rumen functions, microbial colonization and functional interactions in yaks from birth to adulthood. Bacteria, eukaryotes, archaea and viruses colonized the rumen of yaks from birth to adulthood, with bacteria being the majority. Bacteroidetes and Firmicutes were the dominant phyla in five developmental stages, and the abundance of genus and significantly decreased with age. Glycoside hydrolase (GH) genes were the most highly represented in five different developmental stages, followed by glycosyltransferases (GTs) and carbohydrate-binding modules (CBMs), where the proportion of genes coding for CBMs increased with age. Integrating host transcriptome and microbial metagenome revealed 30 gene modules related to age, muscle layer thickness, nipple length and width of yaks. Among these, the MEmagenta and MEturquoise were positively correlated with these phenotypic traits. Twenty-two host genes involved in transcriptional regulation related to metal ion binding (including potassium, sodium, calcium, zinc, iron) were positively correlated with a rumen bacterial cluster 1 composed of , , , , , etc. Therefore, these studies help us to understand the interaction between rumen host and microorganisms in yaks at different ages, and further provide a reliable theoretical basis for the development of feed and mineral element supplementation for yaks at different ages.
PubMed: 38731369
DOI: 10.3390/ani14091365 -
Food Science & Nutrition May 2024In this study, to investigate spp. contamination post-scalding and de-feathering, post-evisceration, post-chilling, and packaged products, which are the most essential...
In this study, to investigate spp. contamination post-scalding and de-feathering, post-evisceration, post-chilling, and packaged products, which are the most essential contamination stages of broiler slaughter, a total of 108 samples were taken from three different broiler slaughterhouses at different times. Isolates obtained by cultural methods in 104 of 108 samples were analyzed by mPCR method to identify pathogen spp. , , and mixed contamination of both species were detected in 51 samples. Of the 51 isolates, 27 (52.9%) were , 16 (31.4%) were , and 8 (15.7%) were mixed contamination of and , while was not detected. and contamination was 59.2% post-scalding and de-feathering, 43.4% post-evisceration, 44.4% and 48.1% post-chilling and in packaged products, respectively. All strains were found to be 100% resistant to cefoperazone and penicillin and sensitive to tetracycline. strains were 100% resistant to cefoperazone, penicillin, and cloxacillin and susceptible to tetracycline and erythromycin. In the study, it was determined that spp. caused a very intense contamination (85.18%-100%) and also contamination rates of identified pathogen strains ( and ) were very high (59.2% and 43.4%) in broiler slaughtering stages. Considering that each step in broiler slaughter could contaminate the next stage, developing a safe slaughter and minimizing the risk toward the final product, it was concluded that critical control points could not be well managed in broiler slaughterhouses, and broiler meat may pose a significant risk to public health.
PubMed: 38726459
DOI: 10.1002/fsn3.4013