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Microorganisms Oct 2023is the causative agent of septicemia in fish, and it is associated with significant economic losses in the aquaculture industry. While piscine infections are mainly...
is the causative agent of septicemia in fish, and it is associated with significant economic losses in the aquaculture industry. While piscine infections are mainly treated with antibiotics, the emergence of resistance in bacterial populations requires the development of alternative methods of treatment. The use of phages can be one of them. A novel jumbo phage, AerS_266, was isolated and characterized. This phage infects only mesophilic strains and demonstrates a slow lytic life cycle. Its genome contains 243,674 bp and 253 putative genes: 84 encode proteins with predicted functions, and 3 correspond to tRNAs. Genes encoding two multisubunit RNA polymerases, chimallin and PhuZ, were identified, and AerS_266 was thus defined as a phiKZ-like phage. While similar phages with genomes >200 kb specific to and have been previously described, AerS_266 is the first phiKZ-like phage found to infect .
PubMed: 38004661
DOI: 10.3390/microorganisms11112649 -
Journal of Insect Science (Online) Nov 2023Insect gut bacteria play an essential role in the nutritional metabolism, growth, and development of insects. Grasshoppers (Orthoptera) are cellulose-rich plant-feeding...
Insect gut bacteria play an essential role in the nutritional metabolism, growth, and development of insects. Grasshoppers (Orthoptera) are cellulose-rich plant-feeding pests. Although the biological potential of grasshopper gut microorganisms to assist cellulose decomposition is well established, microbial resources for efficient degradation of cellulose biomass are still scarce and need to be developed. In this study, we used selective media to isolate cellulose-degrading bacteria from the intestines of Atractomorpha sinensis, Trilophidia annulata, Sphingonotus mongolicus, and Calliptamus abbreviatus. Phylogenetic analysis based on the maximum likelihood method using 16S rDNA sequencing sequences to identify bacteria revealed the isolation of 11 strains belonging to 3 genera, including Klebsiella, Aeromonas, and Bacillus. The degradability of the isolates to cellulose was then determined by the DNS colorimetric method, and the results showed that Bacillus had the highest degradation rate. The elucidation of microbial cellulose degradation capacity in grasshoppers not only contributes to the understanding of multiple plant-insect-microbe interactions, but also provides a valuable microbial resource for solving the biomass conversion of cellulose species problem.
Topics: Animals; Grasshoppers; Phylogeny; Cellulose; Bacteria; Biomass
PubMed: 38006418
DOI: 10.1093/jisesa/iead101 -
Metabolites Jul 2023The development of an exceptionally sensitive diagnostic technique for early identification of aquaculture diseases, specifically Aeromonas hydrophila, is essential for...
The development of an exceptionally sensitive diagnostic technique for early identification of aquaculture diseases, specifically Aeromonas hydrophila, is essential for efficient management of disease outbreaks at aquaculture locations. In this research, a swift and sensitive diagnostic assay employing Loop-mediated isothermal amplification (LAMP) of Aeromonas hydrophila was devised and compared to the conventional qPCR method documented by Rong Wang. Validation of the diagnostic assay was carried out using actual samples obtained from aquaculture fish. The findings revealed that based on the rapid detection of crude bacterial genomic DNA, the fluorescent LAMP assay possessed a lower limit of detection (LOD) of 0.559 ng/μL (0.315-1.693, 95% CI), while the LOD for qPCR stood at 4.301 ng/μL (2.084-8.876, 95% CI). Both techniques demonstrated outstanding specificity, exhibiting no cross-reactivity with bacteria from the same or closely related genera. A total of 74 fish samples suspected to be infected with the fish disease were gathered, with 26 and 23 samples testing positive for Aeromonas hydrophila via LAMP and qPCR, respectively. The concordance analysis for LAMP and qPCR methods generated a Kappa value of 0.909 (0.778-1.000, 95% CI), signifying a high degree of diagnostic consensus. This study highlights that the LAMP assay eliminates the thermal cycle temperature change process of qPCR, uses lysate to crudely extract bacterial genomic DNA, and can complete the detection within 40 min, rendering it a practical and efficient alternative for monitoring disease outbreaks at aquaculture sites.
PubMed: 37512548
DOI: 10.3390/metabo13070841 -
Journal of Global Health Jul 2023Diarrhoea is the second most common cause of death among children under the age of five worldwide. The World Health Organization (WHO) recommends treating diarrhoea with...
BACKGROUND
Diarrhoea is the second most common cause of death among children under the age of five worldwide. The World Health Organization (WHO) recommends treating diarrhoea with oral rehydration therapy, intravenous fluids for severe dehydration, and zinc supplements. Antibiotics are only recommended to treat acute, invasive diarrhoea. Rising antibiotic resistance has led to a decrease in the effectiveness of treatments for diarrhoea.
METHODS
A systematic literature review in PubMed, Web of Science, and EMBASE was conducted to identify articles relevant to antibiotic-resistant childhood diarrhoea. Articles in English published between 1990 to 2020 that described antibiotic resistance patterns of common pathogens causing childhood diarrhoea in low- and middle-income countries were included. The studies were limited to papers that categorized children as 0-5 years or 0-10 years old. The proportion of isolates with resistance to major classes of antibiotics stratified by major WHO global regions and time was determined.
RESULTS
Quantitative data were extracted from 44 articles that met screening criteria; most focused on children under five years. Escherichia coli isolates had relatively high resistance rates to ampicillin and tetracycline in the African (AFR), American (AMR), and Eastern Mediterranean Regions (EMR). There was moderate to high resistance to ampicillin and third generation cephalosporins among Salmonella spp in the AFR, EMR, and the Western Pacific Region (WPR). Resistance rates for ampicillin, co-trimoxazole, and chloramphenicol for Shigella in the AFR started at an alarmingly high rate ( ~ 90%) in 2006 and fluctuated over time. There were limited antibiotic resistance data for Aeromonas, Yersinia, and V. cholerae. The 161 isolates of Campylobacter analysed showed initially low rates of fluoroquinolone resistance with high rates of resistance in recent years, especially in the Southeast Asian Region.
CONCLUSIONS
Resistance to inexpensive antibiotics for treatment of invasive diarrhoea in children under ten years is widespread (although data on 6- to 10-year-old children are limited), and resistance rates to fluoroquinolones and later-generation cephalosporins are increasing. A strong regional surveillance system is needed to carefully monitor trends in antibiotic resistance, future studies should include school-aged children, and interventions are needed to reduce inappropriate use of antibiotics for the treatment of community-acquired, non-invasive diarrhoea.
REGISTRATION
This systematic review was registered in Prospero (registration number CRD42020204004) in August 2020.
Topics: Child; Humans; Child, Preschool; Developing Countries; Anti-Bacterial Agents; Ampicillin; Diarrhea; Cephalosporins; Drug Resistance, Microbial
PubMed: 37475599
DOI: 10.7189/jogh.13.04060 -
Frontiers in Microbiology 2023Bats have a very long evolutionary history and are highly differentiated in their physiological functions. Results of recent studies suggest effects of some host factors...
Bats have a very long evolutionary history and are highly differentiated in their physiological functions. Results of recent studies suggest effects of some host factors (e.g., phylogeny and dietary habit) on their gut microbiota. In this study, we examined the gut microbial compositions of 18 different species of bats. Results showed that Firmicutes, Gammaproteobacteria, and Actinobacteria were dominant in all fecal samples of bats. However, the difference in the diversity of gut microbiota among bats of different phylogenies was notable ( = 0.06). Various species of Firmicutes, Actinobacteria, and Gammaproteobacteria were found to contribute to the majority of variations in gut microbiota of all bats examined, and species were much more abundant in bats that feed on both insects and fish than in those of insectivores. The abundance of various species of , , and ancient bacterial phyla was found to vary among bats of different phylogenies, and various species of varied significantly among bats with different dietary habits. No significant difference in the number of genes involved in various metabolic pathways was detected among bats of different phylogenies, but the abundance of genes involved in 5 metabolic pathways, including transcription; replication, recombination, and repair; amino acid transport and metabolism; and signal transduction mechanisms, was different among bats with different dietary habits. The abundance of genes in 3 metabolic pathways, including those involved in stilbenoid, diarylheptanoid, and gingerol biosynthesis, was found to be different between insectivorous bats and bats that feed on both insects and fish. Results of this study suggest a weak association between dietary habit and gut microbiota in most bats but a notable difference in gut microbiota among bats of different phylogenies.
PubMed: 37577418
DOI: 10.3389/fmicb.2023.1207482 -
Fish and Shellfish Immunology Reports Dec 2023Toll-like receptors (TLRs) play a crucial role in the recognition of microbial-associated molecular patterns in the innate immune system. Fish TLRs have undergone...
Toll-like receptors (TLRs) play a crucial role in the recognition of microbial-associated molecular patterns in the innate immune system. Fish TLRs have undergone significant gene expansion to adapt to complex aquatic environments. Among them, TLR20 from the TLR11 family actively responds to viral and bacterial invasions. Previous studies have reported two TLR20s in grass carp (), and in this study, we revised this conclusion. Based on the latest grass carp genome, we identified a new TLR20 member. These three TLR20s are arranged in tandem on chromosome 9, indicating that they are generated by gene duplication events. They were renamed CiTLR20.1 to CiTLR20.3 based on their chromosomal positions. The CiTLR20s in exhibit higher similarities with those in , and , and lower similarities with those in other distantly related fish species. Selective pressure analysis revealed low conservation and negative evolution of TLR20s during evolution. The 3D structures of the three TLR20s showed significant differences, reflecting functional variations and different downstream adaptor molecule recruitment. Transcriptome data revealed tissue distribution differences of TLR20s, with TLR20.1 showing relatively low expression levels in all the tissues, while TLR20.2 and TLR20.3 showed higher expression in the head kidney, spleen, and gill. Additionally, TLR20.2 and TLR20.3 actively responded to GCRV-II infection, with higher upregulation of TLR20.2 in response to challenge. In conclusion, this study corrected the number of grass carp TLR20 members and analyzed TLR20 from an evolutionary and structural perspective, exploring its role in antiviral and antibacterial defense. This study provides reference for future research on fish TLR20.
PubMed: 37841419
DOI: 10.1016/j.fsirep.2023.100119 -
Veterinary Sciences Nov 2023Bacterial endometritis is among the most common causes of subfertility in mares. It has a major economic impact on the equine breeding industry. The sensitivity of...
Bacterial endometritis is among the most common causes of subfertility in mares. It has a major economic impact on the equine breeding industry. The sensitivity of detecting uterine microbes using culture-based methods, irrespective of the sample collection method, double-guarded endometrial swab, endometrial biopsy, or uterine low-volume lavage (LVL), is low. Therefore, equine bacterial endometritis often goes undiagnosed. Sixteen individual mares were enrolled, and an endometrial sample was obtained using each method from all mares. After trimming, quality control and decontamination, 3824 amplicon sequence variants were detected in the dataset. We found using 16S rRNA sequencing that the equine uterus harbors a distinct resident microbiome during estrus. All three sampling methods used yielded similar results in composition as well as relative abundance at phyla (Proteobacteria, Firmicutes, and Bacteroidota) and genus (, , and levels. A significant difference was found in alpha diversity (Chao1) between LVL and endometrial biopsy, suggesting that LVL is superior at detecting the low-abundant (rare) taxa. These new data could pave the way for innovative treatment methods for endometrial disease and subfertility in mares. This, in turn, could lead to more judicious antimicrobial use in the equine breeding industry.
PubMed: 37999467
DOI: 10.3390/vetsci10110644 -
Heliyon Dec 2023The fish immune system, which consists of innate and adaptive immunologic processes, defends against viruses, bacteria, fungi, and parasites. The gut immunity is an...
The fish immune system, which consists of innate and adaptive immunologic processes, defends against viruses, bacteria, fungi, and parasites. The gut immunity is an integral part of the host immune system that controls immunological homeostasis, hosts' interactions with their microbiomes, and provides defence against a number of intestinal infections. , a facultative air-breathing fish, was experimentally infected with using intraperitoneal injection followed by bath challenge, and transcriptome data were used to examine the gut immune responses during disease progression and recovery from the diseased state without the use of medication. For the control or uninfected fish (FGC) and the infected fish that were kept for seven days (FGE1) and fifteen days (FGE2), separate water tanks were set up. Coding DNA sequences (CDS) for FGC and FGE1, FGC and FGE2, and FGE1 and FGE2 were analyzed for differential gene expression (DGE). The presence and expression of genes involved in the T cell receptor (TCR) signalling pathway, natural killer (NK) cell-mediated cytotoxicity pathway, and complement-mediated pathway, along with a large number of other immune-related proteins, and heat shock protein (HSPs) under various experimental conditions and its relationship to immune modulation of the fish gut was the primary focus of this study. Significant up-and-down regulation of these pathways shows that, in FGE1, the fish's innate immune system was engaged, whereas in FGE2, the majority of innate immune mechanisms were repressed, and adaptive immunity was activated. Expression of genes related to the immune system and heat-shock proteins was induced during this host's immunological response, and this information was then used to build a thorough network relating to immunity and the heat-shock response. This is the first study to examine the relationship between pathogenic bacterial infection, disease reversal, and modification of innate and adaptive immunity as well as heat shock response.
PubMed: 38130423
DOI: 10.1016/j.heliyon.2023.e22936 -
Journal of Food Protection Mar 2024Aquaponic production of fresh produce is a sustainable agricultural method becoming widely adopted, though few studies have investigated potential food safety hazards...
Aquaponic production of fresh produce is a sustainable agricultural method becoming widely adopted, though few studies have investigated potential food safety hazards within commercial systems. A longitudinal study was conducted to isolate and quantify several foodborne pathogens from a commercial, aquaponic farm, and to elucidate their distribution throughout. The survey was conducted over 2 years on a controlled-environment farm containing Nile tilapia (Oreochromis niloticus) and lettuce (Lactuca sativa). Samples (N = 1,047) were collected bimonthly from three identical, independent systems, and included lettuce leaves, roots, fingerlings (7-126 d old), feces from mature fish (>126 d old), water, and sponge swabs collected from the tank interior surface. Most probable number of generic Escherichia coli were determined using IDEXX Colilert Quanti-Tray. Enumeration and enrichment were used to detect Shiga toxin-producing E. coli (STEC), Salmonella enterica, Listeria monocytogenes, Aeromonas spp., Aeromonas hydrophilia, and Pseudomonas aeruginosa. Generic E. coli, STEC, L. monocytogenes, and S. enterica were not detected in collected samples. P. aeruginosa was isolated from water (7/351; 1.99%), swabs (3/351; 0.85%), feces (2/108; 1.85%), and lettuce leaves (2/99; 2.02%). A. hydrophila was isolated from all sample types (623/1047; 59.50%). The incidence of A. hydrophila in water (X = 23.234, p < 0.001) and sponge samples (X = 21.352, p < 0.001) increased over time.
Topics: Animals; Escherichia coli; Aeromonas hydrophila; Longitudinal Studies; Agriculture; Water
PubMed: 38278488
DOI: 10.1016/j.jfp.2024.100230 -
Pathogens (Basel, Switzerland) Nov 2023We studied the phenotypic and genomic characteristics related to the virulence and antibiotic resistance of two strains, which were co-isolated before an outbreak of...
We studied the phenotypic and genomic characteristics related to the virulence and antibiotic resistance of two strains, which were co-isolated before an outbreak of among diseased seabass on Agathonisi Island, Greece, in April 2015. The first strain, AG2.13.2, is a potentially pathogenic mesophilic variant of , and the second, AG2.13.5, corresponds to an related to KN-Mc-11N1 with an ANI value of 97.32%. AG2.13.2 lacks the type III secretion system just like other mesophilic strains of . This characteristic has been associated with lower virulence. However, the genome of AG2.13.2 contains other important virulence factors such as type II and type VI secretion systems, and toxins such as , aerolysin /, and different types of hemolysins. The strain also carries several genes associated with antibiotic resistance such as the efflux pump, and exhibits resistance to tetracycline, ampicillin, and oxolinic acid. In an in vivo challenge test with gilthead seabream larvae, the bv strain AG5.28.6 exhibited the highest virulence among all tested strains. Conversely, both and showed minimal virulence when administered alone. Interestingly, when bv AG5.28.6 was co-administered with , the larvae survival probability increased compared to those exposed to bv AG5.28.6 alone. This finding indicates an antagonistic interaction between bv AG5.28.6 and AG2.13.5. The co-administration of bv AG5.28.6 with did not yield distinct survival probabilities. Our results validate that the primary pathogen responsible for European seabass aeromoniasis is bv .
PubMed: 38003801
DOI: 10.3390/pathogens12111337