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The Journal of Animal Ecology May 2024The mere presence of predators causes prey organisms to display predation-avoidance strategies. Predator presence is often communicated through predator-released...
The mere presence of predators causes prey organisms to display predation-avoidance strategies. Predator presence is often communicated through predator-released chemical signals. Ovipositing female mosquitoes of several species are repelled by unknown signals released from larvivorous fish. It was previously suggested that in many cases, a predator's microbiota plays an important role in the release of these signals; however, this mechanism is still poorly understood. In this study, we looked into the effects of the microbiota originating from the larvivorous Gambusia affinis (Baird and Girard) on the oviposition behaviour of gravid female mosquitoes. We used fish with altered microbiota and bacterial isolates in a set of outdoor mesocosm experiments to address this aim. We show that interference with the fish microbiota significantly reduces fish's repellent effect. We further show that the bacterium Pantoea pleuroti, isolated from the skin of the fish, repels oviposition of Culex laticinctus Edwards and Culiseta longiareolata Macquart mosquitoes similarly to the way in which live fish repel them. Our results highlight the importance of bacteria in the interspecies interactions of their hosts. Furthermore, this finding may lead to the development of an ecologically friendly mosquito repellent, that may reduce the use of larvivorous fish for mosquito control.
Topics: Animals; Female; Oviposition; Cyprinodontiformes; Microbiota; Culicidae; Culex; Insect Repellents
PubMed: 38420662
DOI: 10.1111/1365-2656.14068 -
Annals of Clinical Microbiology and... Nov 2023Globally, surgical site infections (SSI) are the most commonly reported healthcare-associated infections.
BACKGROUND
Globally, surgical site infections (SSI) are the most commonly reported healthcare-associated infections.
METHODS
A multicentre study was conducted among patients who underwent surgical procedures at four hospitals located in Northern (Debre Tabor), Southern (Hawassa), Southwest (Jimma), and Central (Tikur Anbessa) parts of Ethiopia. A total of 752 patients clinically studied for surgical site infection were enrolled. The number of patients from Debre Tabor, Hawassa, Jimma, and Tikur Anbessa, hospitals was 172, 184, 193, and 203, respectively. At each study site, SSI discharge culture was performed from all patients, and positive cultures were characterized by colony characteristics, Gram stain, and conventional biochemical tests. Each bacterial species was confirmed using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI TOF). An antimicrobial susceptibility test (AST) was done on Mueller-Hinton agar using the disk diffusion method. Logistic regression analysis was used to assess associations of dependent and independent variables. A p-value < 0.05 was considered statistically significant. Data were analysed using STATA 16 software.
RESULTS
Among 752 wound discharge cultures performed, 65.5% yielded growth. Among these, 57.9% and 42.1% were Gram-negative and Gram-positive isolates, respectively. In this study, a total of 494 bacteria were isolated; Staphylococcus aureus (31%), Escherichia coli (20.7%), and Klebsiella pneumoniae (9.8%) were the most common. Rare isolates (0.8% each) included Raoultella ornithinolytica, Stenotrophomonas maltophilia, Alcalignes faecalis, Pantoea ecurina, Bacillus flexus, and Paenibacillus tylopili. Enterobacteriaceae showed high levels of resistance to most of the tested antibiotics but lower levels of ertapenem (32.9%), amikacin (24.3%), imipenem (20.3%), and meropenem (17.6%) resistance. Multidrug-resistant (MDR) frequency of Enterobacteriaceae at Debre Tabor, Hawassa, Jimma, and Tikur Anbessa hospitals was 84.5%, 96.5%, 97.3%, and 94%, respectively. Ages ≥ 61 years (AOR = 2.83, 95% CI: 1.02-7.99; P 0.046), prolonged duration of hospital stay (AOR = 4.15, 95% CI: 2.87-6.01; P 0.000), history of previous antibiotics use (AOR = 2.83, 95% CI: 1.06-2.80; P 0.028), history of smoking (AOR = 2.35, 95% CI: 1.44-3.83; P 0.001), emergency surgery (AOR = 2.65, 95% CI: 1.92-3.66; P 0.000), and duration of operation (AOR = 0.27, 95% CI: 0.181-0.392; P 0.000) were significant risk factors.
CONCLUSION
The most prevalent isolates from Gram-positive and Gram-negative bacteria across all hospitals were S. aureus and E. coli, respectively. Many newly emerging Gram-negative and Gram-positive bacteria were identified. Variation between hospitals was found for both SSI etiology type and MDR frequencies. Hence, to prevent the emergence and spread of MDR bacteria, standard bacteriological tests and their AST are indispensable for effective antimicrobial stewardship.
Topics: Humans; Anti-Bacterial Agents; Surgical Wound Infection; Cross-Sectional Studies; Staphylococcus aureus; Escherichia coli; Ethiopia; Prospective Studies; Gram-Negative Bacteria; Gram-Positive Bacteria; Drug Resistance, Bacterial; Microbial Sensitivity Tests; Bacteria; Drug Resistance, Multiple, Bacterial
PubMed: 37936207
DOI: 10.1186/s12941-023-00643-6 -
Food Research International (Ottawa,... Oct 2023Light-flavor Baijiu fermentation is a typical spontaneous solid-state fermentation process fueled by a variety of microorganisms. Mechanized processes have been...
Light-flavor Baijiu fermentation is a typical spontaneous solid-state fermentation process fueled by a variety of microorganisms. Mechanized processes have been increasingly employed in Baijiu production to replace traditional manual operation processes, however, the microbiological and physicochemical dynamics in mechanized processes remain largely unknown. Here, we investigated the microbial community succession and flavor compound formation during a whole mechanized fermentation process of light-flavor Baijiu using the conventional dilution plating method, PacBio single-molecule real-time (SMRT) sequencing and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. The results showed that largely different fungal and bacterial communities were involved in the soaking and fermentation processes. A clear succession from Pantoea agglomerans to Bacillus (B.) smithii and B. coagulans in dominant bacterial species and from Cladosporium exasperatum to Saccharomyces cerevisiae and Lichtheimia ramosa in dominant fungal species occurred in the soaking processes. In the fermentation process, the most dominant bacterial species was shifted from Pantoea agglomerans to Lactobacillus (La.) acetotolerans and the most dominant fungal species were shifted from Lichtheimia ramose and Rhizopus arrhizus to Saccharomyces cerevisiae. The bacterial and fungal species positively associated with acidity and the formation of ethanol and different flavor compounds were specified. The microbial species exhibited strong co-occurrence or co-exclusion relationships were also identified. The results are helpful for the improvement of mechanized fermentation process of light-flavor Baijiu production.
Topics: Saccharomyces cerevisiae; Fermentation; Bacillus; Ethanol; Microbiota; Pantoea
PubMed: 37689903
DOI: 10.1016/j.foodres.2023.113139 -
Folia Microbiologica Dec 2023Adaxial, abaxial phylloplane (leaf), and spermoplane (seed) are proximal yet contrasting habitats for a microbiota that needs to be adequately explored. Here, we...
Adaxial, abaxial phylloplane (leaf), and spermoplane (seed) are proximal yet contrasting habitats for a microbiota that needs to be adequately explored. Here, we proposed novel methods to decipher the adaxial/abaxial-phylloplane and spermoplane-microbiomes. Comparison of 22 meta barcoded-NGS datasets (size of total data set-1980.48 Mb) enabled us to fine-map the microbiome of the rice foliar niche, which encompasses the lower, middle, top leaf as well panicle. Here, the total- and the cultivable-microbiome profiling revealed 157 genera representing ten phyla and 87 genera from 4 bacterial phyla, respectively, with a predominance of Proteobacteria and Actinobacteria. Interestingly, more bacterial communities (124-genera) preferred the abaxial than the adaxial phylloplane (104-genera) and spermoplane (67-genera) for colonization. The microbiome profiles were nearly identical on the aromatic (125-genera) and non-aromatic rice (116-genera) with high representation of Pantoea, Methylobacterium, Curtobacterium, Sphingopyxis, and Microbacterium. The culturomics investigation confirmed the abundance of Pantoea, Chryseobacterium, Pseudomonas, Acinetobacter, Sphingobacterium, and Exiguobacterium. One hundred bacterial isolates characterized and identified by polyphasic-taxonomic tools revealed the dominance of Acinetobacter, Chryseobacterium, Enterobacter, Massilia, Pantoea, Pseudomonas, and Stenotrophomonas on adaxial/abaxial-phylloplane and spermoplane. The study culminated in identifying hitherto unexplored bacterial communities on the adaxial/abaxial phylloplane and spermoplane of rice that can be harnessed for microbiome-assisted rice cultivation in the future.
Topics: Oryza; Genotype; Plant Leaves; Microbiota; Sphingomonadaceae
PubMed: 37165300
DOI: 10.1007/s12223-023-01055-x -
Frontiers in Plant Science 2023The Bunge, widely distributed in North China, shows excellent tolerance to low-P soils. However, little information is available on potential phosphate-solubilizing...
The Bunge, widely distributed in North China, shows excellent tolerance to low-P soils. However, little information is available on potential phosphate-solubilizing bacterial (PSB) strains from the rhizosphere. The objectives of this work were to isolate and characterize PSB from rhizosphere soil and to evaluate the effect of inoculation with the selected strain on seedlings. The strains were characterized on the basis of phenotypic characteristics, carbon source utilization pattern, fatty acid methyl esters analysis, 16S rRNA gene and the whole-genome sequence. A Gram-negative and rod-shaped bacterium, designated MQR6, showed a high capacity to solubilize phosphate and produce indole-3-acetic acid (IAA) and siderophores. The strain can solubilize tricalcium phosphate (TCP) and rock phosphate (RP), and the solubilization of TCP was about 60% more effective than RP. Phylogenetic analyses based on the 16S rRNA gene and whole-genome sequences revealed that strain MQR6 formed a distinct phyletic lineage as a new species within the genus . The digital DNA-DNA hybridization value between strain MQR6 and the closely related strains was 19.5-23.3%. The major cellular fatty acids were summed feature 3 (Cω7c and/or Cω6c), summed feature 8 (Cω6c and/or Cω7c), C, C, and C cyclo. Several genes related to IAA production, phosphonate transport, phosphate solubilization and siderophore biogenesis were found in the MQR6 genome. Furthermore, inoculation with the strain MQR6 significantly improved plant height, trunk diameter, dry weight and P accumulation in roots and shoot of seedlings compared to non-inoculated control. These plant parameters were improved even further in the treatment with both inoculation and P fertilization. Our results suggested that MQR6 represented a new species we named , as a plant growth-promoting rhizobacterium that can solubilize inorganic P and improve growth of seedlings, emerging as a potential strategy to improve cultivation.
PubMed: 37521910
DOI: 10.3389/fpls.2023.1218445 -
Applied and Environmental Microbiology Jun 2024
PubMed: 38722171
DOI: 10.1128/aem.00629-24 -
Journal of Basic Microbiology Dec 2023Heavy metal pollution has posed a severe danger to environmental stability due to its high toxicity and lack of biodegradability. The present study deals with the...
Heavy metal pollution has posed a severe danger to environmental stability due to its high toxicity and lack of biodegradability. The present study deals with the appraisement of tolerance shown by various bacteria in varied copper and iron concentrations. Among the 20 isolates, four isolates, GN2, SC5, SC8, and SC10, exhibiting more significant iron and copper tolerance, were selected and identified by 16 S ribosomal ribonucleic acid (rRNA) gene sequence analysis as Pantoea agglomerans strain GN2, Pantoea sp. strain SC5, Bacillus sp. strain SC8 and Priestia aryabhattaistrain SC10. The minimum inhibitory concentration of molecularly identified strains revealed that P. agglomerans strain GN2 showed tolerance to iron sulfate and copper sulfate upto 600 and 400 µg/mL, whereas Bacillus sp. SC8 (OQ202165) showed tolerance of 700 and 250 µg/mL were tolerant to iron sulfate and copper sulfate up to 700 and 150 µg/mL, respectively. Pantoea sp. strain SC5 showed significant tolerance to both heavy metals. The isolates were further studied for their ability to grow at varying temperatures and pH ranges. Most of the isolates showed optimal growth at 37°C and pH 7. However, Pantoea sp. SC5 was competent to have prominent growth at 45°C and pH 8.0. Microbial remediation, which is eco-friendly, has proven the most effective method for bioremediation of heavy metal-contaminated environments. Using heavy metal-resistant bacteria for microbial remediation of iron and copper-contaminated environments could be a viable and valuable strategy. These isolates could also be used to decontaminate heavy metal-polluted agricultural soils.
Topics: Copper; Copper Sulfate; Metals, Heavy; Bacteria; Bacillus; Iron; Biodegradation, Environmental; Soil Pollutants
PubMed: 37712102
DOI: 10.1002/jobm.202300349 -
Journal of Applied Microbiology Sep 2023The purpose of this study was to determine whether plant-associated bacteria (PAB) can reduce Salmonella enterica colonization and infection of alfalfa sprouts to reduce...
AIMS
The purpose of this study was to determine whether plant-associated bacteria (PAB) can reduce Salmonella enterica colonization and infection of alfalfa sprouts to reduce the risk of foodborne illness.
METHODS
We isolated PAB from alfalfa seeds and sprouts. Monoclonal isolates of the bacteria were obtained and tested for their ability to inhibit Salmonella Typhimurium growth in alfalfa sprouts over 6 days. Genome sequencing and annotation were used to construct draft genomes of the bacteria isolated in this study using Illumina sequencing platform.
RESULTS
We observed that a cocktail of five PAB could reduce Salmonella growth in alfalfa sprouts from ∼108 to ∼105 CFU g-1, demonstrating a protective role. Genome sequencing revealed that these bacteria were members of the Pseudomonas, Pantoea, and Priestia genus, and did not possess genes that were pathogenic to plants or animals.
CONCLUSIONS
This work demonstrates that PAB can be utilized to reduce pathogen levels in fresh produce, which may be synergistic with other technologies to improve the safety of sprouts and other fresh produce.
Topics: Animals; Salmonella enterica; Medicago sativa; Bacillaceae; Salmonella typhimurium; Foodborne Diseases; Vegetables
PubMed: 37669894
DOI: 10.1093/jambio/lxad204 -
Environmental Pollution (Barking, Essex... Aug 2023Antibiotics have been widely used in animal husbandry, which leads to high risk of food-borne transfer of antibiotic resistance genes (ARGs). The present study...
Antibiotics have been widely used in animal husbandry, which leads to high risk of food-borne transfer of antibiotic resistance genes (ARGs). The present study investigated the distribution of β-lactamase resistance genes (β-RGs) on dairy farm in the Songnen Plain of western Heilongjiang Province, China, to provide mechanistic insights into food-borne transmission of β-RGs through "meal-to-milk" chain under practically relevant circumstances. The results demonstrated that the abundance of β-RGs (91%) was much higher than that of other ARGs in the livestock farms. The blaTEM exhibited the content as high as 94.55% among all ARGs, and higher than 98% blaTEM was detected in meal, water and milk sample. The metagenomic taxonomy analysis indicated that the blaTEM should be carried by tnpA-04 (7.04%) and tnpA-03 (1.48%) hosted in Pseudomonas genus (15.36%) and Pantoea (29.02%) genus. Both tnpA-04 and tnpA-03 in the milk sample were identified to be the key mobile genetic elements (MGEs) responsible for transferring blaTEM along the "meal-manure-soil-surface water-milk" chain. The ARGs transfer across ecological boundaries underscored the need to evaluate potential dissemination of high-risk Proteobacteria and Bacteroidetes carried by humans and animals. They were capable of producing expanded-spectrum β-lactamases (ESBLs) and destroying commonly used antibiotics, leading to possible risk of food-borne horizontal transmission of ARGs. This study not only has important environmental implications for identifying the pathway for ARGs transfer, but also highlights the demand for appropriate policy toward safe regulation of dairy farm and husbandry products.
Topics: Animals; Humans; Genes, Bacterial; Farms; Milk; Manure; beta-Lactam Resistance; Anti-Bacterial Agents
PubMed: 37209898
DOI: 10.1016/j.envpol.2023.121831 -
The ISME Journal Sep 2023The phyllosphere is densely colonised by microbial communities, despite sparse and heterogeneously distributed resources. The limitation of resources is expected to...
The phyllosphere is densely colonised by microbial communities, despite sparse and heterogeneously distributed resources. The limitation of resources is expected to drive bacterial competition resulting in exclusion or coexistence based on fitness differences and resource overlap between individual colonisers. We studied the impact of resource competition by determining the effects of different bacterial colonisers on the growth of the model epiphyte Pantoea eucalypti 299R (Pe299R). Resource overlap was predicted based on genome-scale metabolic modelling. By combining results of metabolic modelling and pairwise competitions in the Arabidopsis thaliana phyllosphere and in vitro, we found that ten resources sufficed to explain fitness of Pe299R. An effect of both resource overlap and phylogenetic relationships was found on competition outcomes in vitro as well as in the phyllosphere. However, effects of resource competition were much weaker in the phyllosphere when compared to in vitro experiments. When investigating growth dynamics and reproductive success at the single-cell resolution, resource overlap and phylogenetic relationships are only weakly correlated with epiphytic Pe299R reproductive success, indicating that the leaf's spatial heterogeneity mitigates resource competition. Although the correlation is weak, the presence of competitors led to the development of Pe299R subpopulations that experienced different life histories and cell divisions. In some in planta competitions, Pe299R benefitted from the presence of epiphytes despite high resource overlap to the competitor strain suggesting other factors having stronger effects than resource competition. This study provides fundamental insights into how bacterial communities are shaped in heterogeneous environments and a framework to predict competition outcomes.
Topics: Phylogeny; Bacteria; Reproduction
PubMed: 37355740
DOI: 10.1038/s41396-023-01459-0