Search Results (64)

Subclinical mastitis is a critical disease affecting camel health and milk quality. However, research on shifts in milk bacterial communities following subclinical mastitis in camels is limited. We evaluated changes in bacterial communities following subclinical mastitis in Bactrian camels. Three portions of California Mastitis Test (CMT)-negative milk and five portions of CMT-positive milk were collected from each Jimunai County and Keping County using the CMT, and the bacterial community composition of the camel milk was analyzed using amplicon sequencing of the v34 region of the 16S rRNA gene. Subclinical mastitis induced genus-level differences in the core bacterial microbiota of Bactrian camel milk. To our knowledge, Delftia was identified in camel milk for the first time, predominantly in Jimunai County. Bacterial abundance in camel milk from Keping County was increased and altered. Alpha diversity analysis revealed that subclinical mastitis induced lower and higher bacterial abundance in milk from Jimunai County and Keping County, respectively, compared to that of healthy camels. Therefore, these findings provide direction for future research on pathogenic microorganisms for the prevention and control of subclinical mastitis in Bactrian camels. Full article

The cotton aphid, Aphis gossypii, is a globally significant agricultural pest whose microbiota plays vital roles in its physiology and adaptation. However, the dynamics of bacterial communities across its developmental stages remain poorly understood. This study employed full-length 16S rRNA gene sequencing to characterize the microbiota structure, diversity, and functional potential in nine developmental stages of A. gossypii, including egg, nymph (1-, 3-, 5-, 7-day-old), and adult (1-, 3-, 5-, 7-day-old). Results revealed Proteobacteria (72.75–95.51%) as the dominant phylum across all stages, with Buchnera aphidicola (primary obligate symbiont) constituting over 23.83% of bacterial abundance and peaking in eggs (≈80%). Alpha diversity indices (Shannon, Simpson) indicated significantly higher microbial diversity in nymphs compared to adults, suggesting stage-specific ecological interactions. While beta diversity analysis showed no structural clustering by developmental stage, functional predictions highlighted enrichment in metabolic pathways (>73% of genes), though limitations in 16S-based functional inference were noted. Notably, facultative symbionts like Hamiltonella or Serratia were absent, contrasting with other aphid systems. Dynamic shifts in Buchnera titer and the prominence of Delftia tsuruhatensis and Enterobacter hormaechei implied potential roles in host adaptation. These findings highlight the persistent dominance of the obligate symbiont Buchnera aphidicola across all developmental stages, despite quantitative fluctuations in its abundance, alongside stage-specific shifts in facultative bacterial communities, offering insights into novel targets for microbiome-driven pest management strategies. Further multi-omics approaches are warranted to validate functional contributions of these microbial communities. Full article

Sulfur cycling is a fundamental biogeochemical process, yet its microbial underpinnings in environments like the Isinuka sulfur pool remain poorly understood. Using high-throughput Illumina 16S rRNA sequencing and PICRUSt-based functional inference, we analyzed bacterial diversity and metabolic potential in sediment and water samples. Sediments, characterized by high sulfide/sulfate/thiosulfate, salinity, alkalinity, and organic matter content under anoxic conditions, supported diverse sulfur-reducing and organic-degrading bacteria, primarily from the Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria phyla. In contrast, the anoxic water column harbored a less diverse community dominated by α-, γ-, and β-Proteobacteria, including Thiocapsa and Lutimaribacter. Sulfur oxidation genes (soxABCXYZ, sqr) were abundant in water, while sulfate reduction genes (dsrAB, aprAB, and sat/met3) were concentrated in sediments. Core microbiome analysis identified Thiocapsa, Lutimaribacter, and Delftia as functional keystones, integrating sulfur oxidation and nutrient recycling. Sediments supported dissimilatory sulfate-reducing bacteria (unclassified Desulfobacteraceae, Desulfosarcina, Desulfococcus, Desulfotignum, and Desulfobacter), while water samples were enriched in sulfur-oxidizing bacteria like Thiocapsa. Metabolic profiling revealed extensive sulfur, nitrogen, and carbon cycling pathways, with sulfur autotrophic denitrification and anoxygenic photosynthesis coupling sulfur–nitrogen and sulfur–carbon cycles. This study provides key theoretical insights into the microbial dynamics in sulfur-rich environments, highlighting their roles in biogeochemical cycling and potential applications in environmental management. Full article

Delftia acidovorans (D. acidovorans) is a non-fermentative, aerobic, Gram-negative bacillus typically found in environmental sources such as soil and water. Although considered an opportunistic pathogen, it has been implicated in both immunocompromised and immunocompetent individuals. This study presents a case of persistent cathether-related bacteraemia in a 61-year-old haemodialysis patient and offers a systematic literature review of similar cases. The patient, affected by end-stage kidney disease and dependent on a central venous catheter (CVC), presented with septic shock. Blood cultures confirmed D. acidovorans, resistant to aminoglycosides but sensitive to cephalosporins, piperacillin/tazobactam, and fluoroquinolones. Despite appropriate antibiotic therapy, bacteraemia persisted, prompting the use of taurolidine lock therapy when catheter removal was initially unfeasible. Blood cultures cleared after nine days, and the catheter was later replaced. A systematic review following PRISMA guidelines identified 21 additional cases of D. acidovorans bacteraemia. Most (76.2%) occurred in immunocompromised patients, particularly those with malignancies, chronic haemodialysis, or indwelling devices. Infections in immunocompetent individuals were typically associated with intravenous drug use or environmental exposure. Mortality was approximately 19%. Aminoglycoside resistance was consistent across most cases, while susceptibility to piperacillin/tazobactam, cephalosporins, and carbapenems was generally preserved. Given its resistance profile and ability to form biofilms, D. acidovorans poses a management challenge, particularly in catheter-associated infections. Rapid identification and targeted antimicrobial therapy are crucial. Adjunctive measures such as taurolidine lock therapy can be beneficial when device removal is not immediately possible. Full article

Nanoparticles are proposed as alternatives to traditional antimicrobial agents. By manipulating a nanoparticle’s core and surface coating, antimicrobial effects against various microbial populations can be customized, known as the “designer effect”. However, the antimicrobial properties of nanoparticle core–coating combinations are understudied; little research exists on their effects on diverse bacteria. The antimicrobial effects of surface-stabilized zero-valent iron nanoparticles (FeNPs) are particularly interesting due to their stability in water and ferromagnetic properties. This study explores the impact of FeNPs coated with three surface coatings on six diverse bacterial species. The FeNPs were synthesized and capped with L-ascorbic acid (AA), cetyltrimethylammonium bromide (CTAB), or polyvinylpyrrolidone (PVP) using a bottom-up approach. Zone of inhibition (ZOI) values, assessed through the disc diffusion assay, indicated that AA-FeNPs and CTAB-FeNPs displayed the most potent antibacterial activity. Bacteria inhibition results ranked from most sensitive to least sensitive are the following: Bacillus nealsonii > Escherichia coli > Staphylococcus aureus > Delftia acidovorans > Chryseobacterium sp. > Sphingobacterium multivorum. Comparisons using ordinal regression and generalized linear mixed models revealed significant differences in bacterial responses to the different coatings and nanoparticle concentrations. The statistical model results are in agreement, thus increasing confidence in these conclusions. This study supports the feasibility of the “designer nanoparticle” concept and offers a framework for future research. Full article

The presence and biological role of extracellular DNA (eDNA) have been explored in diverse microbial environments. Nonetheless, it has not been studied in the chicken gut microbiome. This study aims to investigate eDNA in the chicken cecum, analyzing cecal samples from broiler chickens using three preparation methods: Whole Cecal Suspension (WCS), Washed Cell Pellets (WCP), and Cell-Free Supernatant (CFS). The 16S rRNA gene-based microbiota analysis revealed distinct microbial communities in CFS compared to WCS and WCP (p = 0.001). Notably, specific taxa, including Anaerofilum, Anaerotruncus, Oscillospira, Syntrophomonas, and Delftia, were enriched in CFS. Confocal fluorescence microscopy, employing stains such as Propidium Iodide (PI), GelGreen, and SYTO 9, confirmed the presence of eDNA with filaments observed in WCS and CFS. Colocalization of PI and GelGreen™ validated the extracellular nature of eDNA, while DNase I treatment selectively degraded eDNA, further confirming its extracellular nature. Our findings in this study highlight the presence of eDNA in the chicken cecal microbiome, and the presence of eDNA associated with specific taxonomic groups suggest that it might play a specific role in the biological function of the cecal microbiome, which warrants further investigation in the future. Full article

Ofloxacin is one of the most commonly used antibacterial substances in the world. Like most medicines, it ends up in the environment through municipal sewage and undergoes various transformations, e.g., photodegradation. The aim of this study was an extensive analysis of ofloxacin photodegradation in both pure antibiotic and a commercial eye drop forms. In this study, a sunlight simulator, chromatographic methods of quantitative and qualitative determination, and biological methods for the evaluation of toxicity (Microbial Assay for Risk Assessment (MARA), Microtox^® and Spirotox) were used. The results showed that ofloxacin decomposed almost completely over 2 h of irradiation. Based on the high resolution mass spectrometry, 22 photoproducts were identified. The most sensitive strain of bacteria in the MARA test (Delftia acidovorans) responded at a concentration of 7.6 µg L⁻¹ of ofloxacin. The antibacterial activity of the irradiated samples was higher than that predicted based on the ofloxacin concentration. This suggests that the resulting photoproducts may have a bacteriostatic effect. The results of additional acute toxicity tests indicate the formation of toxic photoproducts, so it is reasonable to use other organisms that are not focused on a specific target. Such actions may allow for the capture of other, unexpected effects of formed photoproducts. Full article

Malaria disease affects millions of people annually, making the Amazon Basin a major hotspot in the Americas. While traditional control strategies rely on physical and chemical methods, the Anopheles microbiome offers a promising avenue for biological control, as certain bacteria can inhibit parasite development and alter vector immune and reproductive systems, disrupting the transmission cycle. For this reason, this study aimed to explore the bacterial communities in An. darlingi and An. triannulatus s.l., including breeding sites, immature stages, and adults from San Pedro de los Lagos (Leticia, Amazonas) through next-generation sequencing of the 16S rRNA gene. The results revealed a higher bacterial genus richness in the L1–L2 larvae of An. triannulatus s.l. Aeromonas and Enterobacter were prevalent in most samples, with abundances of 52.51% in L3–L4 larvae and 48.88% in pupae of An. triannulatus s.l., respectively. In breeding site water, Verrucomicrobiota bacteria were the most dominant (52.39%). We also identified Delftia (15.46%) in An. triannulatus s.l. pupae and Asaia (98.22%) in An. triannulatus, linked to Plasmodium inhibition, and Elizabethkingia, in low abundances, along with Klebsiella and Serratia, known for paratransgenesis potential. Considering the high bacterial diversity observed across the different mosquito life stages, identifying bacterial composition is the first step towards developing new strategies for malaria control. However, the specific roles of these bacteria in anophelines and the malaria transmission cycle remain to be elucidated. Full article

Pancreatic ductal adenocarcinoma (PDAC) is associated with intratumoral microbiota changes. However, defining the normal pancreatic microbial composition remains a challenge. Herein, we tested the hypothesis that the microbial profiling of normal pancreatic tissue from healthy organ donors (HC) could help in determining the signature of microbiota in PDAC. Matched pairs of tumor and normal tissues from PDAC patients (n = 32) and normal pancreatic tissues from HC (n = 17) were analyzed by 16S rRNA gene sequencing. Dissimilarities in all the beta metrics emerged in both normal samples and tumor samples, compared to HC (Bray–Curtis dissimilarity and Jaccard distance: p = 0.002; weighted UniFrac distances: p = 0.42 and p = 0.012, respectively; unweighted UniFrac distance: p = 0.009); a trend toward a lower Faith’s phylogenetic distance was found at the tumor level vs. HC (p = 0.08). Within PDAC, a lower Faith’s phylogenetic distance (p = 0.003) and a significant unweighted UniFrac distance (p = 0.024) were observed in tumor samples vs. normal samples. We noted the presence of a decreased abundance of bacteria with potential beneficial effects (Jeotgalicoccus) and anticancer activity (Acinetobacter_guillouiae) in PDAC vs. HC; bacteria involved in immune homeostasis and suppression of tumor progression (Streptococcus_salivarius, Sphingomonas) were reduced, and those implicated in tumor initiation and development (Methylobacterium-Methylorubrum, g_Delftia) were enhanced in tumor samples vs. normal samples. Metagenomic functions involved in fatty acid synthesis were reduced in normal samples compared to HC, while peptidoglycan biosynthesis IV and L-rhamnose degradation were more abundant in tumor samples vs. normal samples. Future prospective studies on larger populations, also including patients in advanced tumor stages and considering all potential existing confounding factors, as well as further functional investigations, are needed to prove the role of microbiota-mediated pathogenicity in PDAC. Full article

Plant microbiomes play a major role in plant health, growth, and development, enhancing resistance to pathogen invasion. However, despite the extensive research on the phyllosphere microbiome, it remains unclear how the microbiome of leaves in proximity to diseased leaves responds to pathogen invasion. We investigate the response of the maize phyllosphere microbiome to maize white spot by assessing the microbiome dynamics associated with the white spot portion and the area in proximity using 16S and ITS high-throughput sequencing analysis. Our results showed that the bacterial diversities were higher in the diseased portion and area in proximity to the spot than those in healthy plants. At the same time, lower fungal diversity was recorded in the diseased portion compared to portions in proximity to it and healthy leaves. The spot portion had a significant influence on the microbial composition. The diseased portion, the area in proximity to it, and the healthy leaves were dominated by the bacterial genera Sphingomonas, Delftia, Chryseobacterium, Stenotrophomonas, Methylobacterium-methylorubrum, and Bacteroides. Still, the abundance of Sphingomonas decreased in the healthy leaves with a corresponding increase in Stenotrophomonas. Conversely, the fungal genus Setophoma dominated the diseased portion, while the fungal pathogens Cladosporium, Alternaria, and Exserohilum were highly abundant in the samples from the area in proximity to it. In addition, a co-occurrence network analysis revealed a complex fungal network in healthy leaves and those in proximity to leaves infected with white spot compared to the diseased portion. This study suggests that the area in proximity to the maize leaf infected with white spot disease is colonized by more harmful plant pathogenic fungi for disease progression. Full article

Uncultured microorganisms represent a promising and untapped source of antibacterial compounds, crucial in the fight against the significant threat of antimicrobial resistance (AMR). In this study, both traditional and isolation chip (iChip) cultivation techniques were employed to enhance the recovery of known and unknown microorganisms from soils located in Normandy, France. The isolates obtained were identified using 16S rDNA or ITS regions analysis and MALDI-TOF mass spectrometry and were screened for antibacterial activity. A total of 386 isolates, belonging to 6 microbial phyla and distributed across 65 genera, were recovered using both methods. In total, 11 isolates are potentially new bacterial species, and 34 were associated with 22 species described recently. The iChip method yielded a higher diversity of microorganisms (47 genera) than the traditional method (38 genera) and was particularly effective in enriching Actinomycetota. Antibacterial screening against target bacteria showed that 85 isolates (22%) exhibited antibacterial activity. The Streptomyces, Pseudomonas, and Bacillaceae taxa accounted for most antibacterial-producing bacteria with some presenting promising undescribed characteristics. Other active isolates were affiliated with less-known antibacterial producers such as Arthrobacter, Chryseobacterium, Delftia, Ensifer, Flavobacterium, Rahnella, and Stenotrophomonas, among others. These results highlight the potential of our microbial collection as a source of new antibacterial natural products. Full article

Maize (Zea mays L.) is an important cereal crop species for food, feedstock and industrial material. Maize seeds host a suitable ecosystem for endophytic bacteria, facilitating seed germination and seedling growth. However, the inheritance, diversity and potential function of seed endophytic bacteria in maize remain largely unexplored. In this study, the endophytic bacteria in the seeds of maize inbred line WU109 collected during three consecutive seasons were identified using 16S rDNA sequencing. Core community composition was essentially consistent across three seed generations and two planting locations. In total, 212 operational taxonomic units (OTUs) belonging to 11 phyla were identified, among which proteobacteria was the dominant phylum. Fifty-six OTUs were conserved across three seed generations. Within them, 16 OTUs were core components and the dominant OTUs were Ralstonia solanacearum, Delftia tsuruhatensis, Bacillu svelezensis and Shigella boydii, accounting for 60% of the total abundance of OTUs. COG and KEGG analyses showed that the function of seed endophytic bacteria was mainly enriched in metabolic processes, especially in amino acid, carbohydrate and energy metabolism. Taken together, the results suggested that the community of maize seed endophytic bacteria was likely co-shaped by both genetic determination and the environment, while the core constitutes of seed endophytes were largely conserved due to transgenerational transmission. Establishing the mutualistic link between the maize seed and its endophytic bacteria enables the exploitation of the potential of endophytes for enhancing crop production. This finding provides a reference to better understand the inheritance and composition of seed core endophytic bacteria in maize. Full article

The investigation of metabolic pathways and regulatory mechanisms in newly discovered species can offer valuable insights into the nitrogen removal function of heterotrophic nitrification–aerobic denitrification (HN-AD) bacteria. To investigate the nitrogen removal mechanism of a new genus, Delftia, we analyzed the complete genome, metabolic pathways, and the related genes of Delftia sp. B7. We further examined the nitrogen removal capacity of Delftia sp. B7 under various nitrogen sources and real wastewater. Our results demonstrate the presence of several genes in Delftia sp. B7, including narGHI, nasAB, nirK, nirS, nirBD, norBC, nosZ, nxrAB, gdhA, glnA, gltBD, amt, and nrt. These genes encode enzymes that facilitate ammonia assimilation, assimilatory nitrate reduction to nitrite, HN-AD, and dissimilatory nitrate reduction (DNRA) in Delftia sp. B7. Specifically, we propose an HN-AD pathway in Delftia sp. B7, NH₄⁺-N → NH₂OH → NO₂⁻-N → NO₃⁻-N → NO₂⁻-N → NO → N₂O → N₂, which accounts for the majority of nitrogen removal. Here, the transformation of NH₄⁺-N to NO₂⁻-N was achieved by unknown enzymes or by another pathway. When treating municipal wastewater, Delftia sp. B7 was able to remove 45.62 ± 1.29% of TN. These findings provide a theoretical basis for utilizing microbial resources to mitigate nitrogen contamination. Full article

Autism Spectrum Disorder (ASD) is a multifactorial disorder involving genetic and environmental factors leading to pathophysiologic symptoms and comorbidities including neurodevelopmental disorders, anxiety, immune dysregulation, and gastrointestinal (GI) abnormalities. Abnormal intestinal permeability has been reported among ASD patients and it is well established that disturbances in eating patterns may cause gut microbiome imbalance (i.e., dysbiosis). Therefore, studies focusing on the potential relationship between gut microbiota and ASD are emerging. We compared the intestinal bacteriome and mycobiome of a cohort of ASD subjects with their non-ASD siblings. Differences between ASD and non-ASD subjects include a significant decrease at the phylum level in Cyanobacteria (0.015% vs. 0.074%, p < 0.0003), and a significant decrease at the genus level in Bacteroides (28.3% vs. 36.8%, p < 0.03). Species-level analysis showed a significant decrease in Faecalibacterium prausnitzii, Prevotella copri, Bacteroides fragilis, and Akkermansia municiphila. Mycobiome analysis showed an increase in the fungal Ascomycota phylum (98.3% vs. 94%, p < 0.047) and an increase in Candida albicans (27.1% vs. 13.2%, p < 0.055). Multivariate analysis showed that organisms from the genus Delftia were predictive of an increased odds ratio of ASD, whereas decreases at the phylum level in Cyanobacteria and at the genus level in Azospirillum were associated with an increased odds ratio of ASD. We screened 24 probiotic organisms to identify strains that could alter the growth patterns of organisms identified as elevated within ASD subject samples. In a preliminary in vivo preclinical test, we challenged wild-type Balb/c mice with Delftia acidovorans (increased in ASD subjects) by oral gavage and compared changes in behavioral patterns to sham-treated controls. An in vitro biofilm assay was used to determine the ability of potentially beneficial microorganisms to alter the biofilm-forming patterns of Delftia acidovorans, as well as their ability to break down fiber. Downregulation of cyanobacteria (generally beneficial for inflammation and wound healing) combined with an increase in biofilm-forming species such as D. acidovorans suggests that ASD-related GI symptoms may result from decreases in beneficial organisms with a concomitant increase in potential pathogens, and that beneficial probiotics can be identified that counteract these changes. Full article

Phosphonates such as ethylenediaminetetra (methylenephosphonic acid) (EDTMP) and aminotris (methylenephosphonic acid) (ATMP) are used every day in water treatment processes or in household products. Their consumption is still increasing, regardless of the debates on their environmental impact. Here, the microbial characterisation and determination of the biodegradation potential of selected industrially relevant phosphonates for the isolate Delftia sp. UMB14 is reported. The opportunistic strain was isolated from a biofilm that was derived from a conventional washing machine using conventional detergents containing phosphonates. In antimicrobial susceptibility testing, the strain was only susceptible to sulfonamide, tetracycline, and chloramphenicol. Physiological and biochemical characteristics were determined using the BIOLOG EcoPlate assay. Most importantly, the strain was shown to convert D-malic acid and D-mannitol, as confirmed for strains of Delftia lacustris, and thus the new isolate could be closely related. Biodegradation tests with different phosphonates showed that the strain preferentially degrades ATMP and EDTMP but does not degrade glyphosate (GS) and amino (methylphosphonic acid) (AMPA). A specific gene amplification confirmed the presence of phnX (phosphonoacetaldehyde hydrolase) and the absence of PhnJ (the gene for the core component of C–P lyase). The presence of PhnCDE is strongly suggested for the strain, as it is common in Delftia lacustris species. Full article