Current Microbiology最新文献

Urban water bodies serve as critical reservoirs of microbial diversity, with major implications for public health and environmental quality. This study aimed to characterize the microbial diversity of surface waters and wastewater from the Pasto River in the Colombian Andean Highlands, offering insights that may support water quality monitoring efforts. Sampling was conducted at three river sites and one wastewater location. Standard physicochemical and microbiological analyses were performed, including real-time PCR to detect protozoan pathogens Giardia spp. and Cryptosporidium spp. Metagenomic sequencing provided an in-depth taxonomic and functional profile of microbial communities through two complementary approaches: (i) read-based analysis to identify abundant families and species, both pathogenic and beneficial, and (ii) detection of health-related molecular markers, including antimicrobial resistance markers and virulence factors. Physicochemical analyses showed distinct profiles between wastewater and surface water, with wastewater exhibiting elevated levels of suspended solids (113.6 mg/L), biochemical oxygen demand (BOD, 311.2 mg/L), and chemical oxygen demand (COD, 426.7 mg/L). Real-time PCR detected Giardia spp. DNA in 75% (76/102) of the samples and Cryptosporidium spp. DNA in 94% (96/102) of samples. The metagenomic read-based profiling identified Aeromonas media as a prevalent pathogen and Polaromonas naphthalenivorans as a potential biodegradative agent. The metagenomic assembly produced 270 high-quality genomes, revealing 16 bacterial species (e. g., Acinetobacter johnsonii and Megamonas funiformis) that provided insights into fecal contaminants and native aquatic microbes. Functional profiling further revealed a high prevalence of antimicrobial resistance markers, particularly for tetracyclines, aminoglycosides, and macrolides, with the highest abundance found in wastewater samples. Additionally, virulence factors were notably present in Zoogloea ramigera. The findings underscore the value of metagenomic profiling as a comprehensive tool for water quality monitoring, facilitating the detection of pathogens, beneficial species, and molecular markers indicative of potential health risks. This approach supports continuous monitoring efforts, offering actionable data for water management strategies to safeguard public health and maintain ecological integrity.

Despite limited studies, free-living birds are considered reservoirs of several diseases, including zoonotic diseases. Thus, we aimed to investigate the presence and characteristics of Campylobacter spp., Escherichia coli, and Salmonella spp. in wild birds assessing their potential risks to human and animal health. Fecal samples were collected from wild and exotic rescued birds, as well as exotic parrots from commercial breeding facilities. Campylobacter spp. and Salmonella spp. were not detected in the samples. E. coli was biochemically confirmed in 58.33% of the samples, resulting nine distinct isolates. PCR analysis identified no enteroinvasive or enteropathogenic E. coli strains, but two isolates were characterized as avian pathogenic E. coli (APEC). The isolates were inoculated into chicken embryos to determine their pathogenicity index, utilizing commensal and pathogenic E. coli strains as controls. All isolates demonstrated higher pathogenicity compared to probiotic bacteria and commensal E. coli. Specifically, two isolates exhibited pathogenicity levels comparable to the positive control (APEC ST131). Furthermore, for the minimum inhibitory concentration (MIC) test, we evaluated 7 antibiotics: ampicillin, ceftazidime, cefotaxime, ciprofloxacin, levofloxacin, colistin, and sulfamethoxazole combined with trimethoprim. Four isolates were classified as multidrug-resistant and the highest level of resistance was to fluoroquinolones. This work demonstrated that wild or captive exotic birds can excrete potentially pathogenic and/or multidrug-resistant E. coli, which may impact the health of other animals and humans.

Increasing antimicrobial resistance and residue in an ecosystem is a huge threat to human as well as animal possibly inviting an uncontrollable outbreak and spoiling food. Use of alternative approaches in tackling the resistance problem has shown promising results in recent past. The present study was targeted to develop and evaluate the use synthetic peptide against biofilm forming methicillin resistant Staphylococcus aureus (MRSA). Peptide evaluation included determination of MIC, time kill kinetics, lysis activity, cell cytotoxicity assay, effect on biofilm formation, mechanism of action, thermo-stability and pH stability. Initially, a synthetic antimicrobial peptide, RWWKARIRL (ANLP-V3) was designed using bioinformatics tools and synthesized by solid phase synthesis using Fmoc chemistry. Peptide was found to exhibit antibacterial activity at 19.5 µg/mL concentration against both ATCC & clinical isolates of S. aureus. The time kill kinetic studies revealed > 99% inhibition of growth after 3 h at MIC, whereas 100% cell inhibition was seen at 2 h at 2 × MIC and 4 × MIC. No cytotoxicity was observed against mice RBCs as well as Vero cells at 2 × MIC. The AMP was found to be thermo-stable as well as pH stable at a wide range. Field emission scanning electron microscopy study demonstrates cell morphological alterations in AMP treated cells indicating membrane interacting nature of AMP. At MIC concentration, effective inhibition of biofilm formation in ATCC strains was seen. In conclusion, designed peptide might be effective antimicrobial agent against methicillin resistant biofilm forming S. aureus underlining possibilities of its preclinical development against mastitis in dairy animals.

The tremendous abundance of Staphylococcus epidermidis (S. epidermidis) on the skin surface have been found electrogenic. However, the role of electrogenic S. epidermidis in biological activities remains elusive. Addition of S. epidermidis plus glycerol reinstated the reduction of electric currents of vancomycin-treated human skin bacteria collected by skin swabs. In the presence of glycerol, an endogenous molecule in human skin, S. epidermidis exerted the electrogenicity measured by the changes in voltages and currents as well as ferrozine assays. A substantial increase in iron contents in skin was detected when mouse skin was exposed to ultraviolet B (UV-B). Topical application of S. epidermidis plus glycerol onto mouse skin mitigated the UV-B-induced production of labile ferrous iron, demonstrating that S. epidermidis electricity acted as a regulator of the redox cycling of irons in skin. Low expression of cyclophilin A, an electron mediator, in S. epidermidis caused the loss of bacterial activities to reduce the UV-B-induced labile ferrous iron. Cumulatively, skin electrogenic S. epidermidis may mediate cyclophilin A to combat the UV-B-induced iron imbalance in skin.

The genus Rahnella has been isolated from human, fish, and water environments. We recently reported on the isolation and genomic identification of a novel pathogen R. aquatilis strain KCL-5 from crucian carp Carassius auratus. To investigate the evolution of bacterial virulence and resistance properties of R. aquatilis, comparative genomics analyses were performed for genus Rahnella strains including R. aquatilis, R. variigena, R. bruchi, and R. victoriana. This analysis provides up-to-date information on genus Rahnella genomic diversity, including comparative analyses of virulence and resistance, synteny, single-nucleotide polymorphisms, average nucleotide identity, core-genes, gene families, and genomic islands. The sister species to R. aquatilis is R. victoriana, and closer R. victoriana than with other Rahnella sp. Multiple genes encoding functions that likely contribute to antimicrobial resistance and pathogenic factors were identified by comparative genome analysis, including multidrug resistance efflux pump, adherence, invasion, and secretion systems. To our knowledge, this is the first report to provide a more detailed insight into the comparative genomic characteristics of Rahnella spp., contributing to the understanding of its diversity and evolution, as well as concerning the virulence of R. aquatilis.

Gut microbial dysbiosis is associated with the development of critical clinical conditions of metabolic syndrome (obesity, type II diabetes), and calcium oxalate kidney stones. The human gut microbial eubiosis with functional probiotics and their heat-killed cells of lactic acid bacteria (LAB) is considered the current therapy for metabolic syndrome (MS). In accordance with this, our study aimed to isolate oxalate-degrading, cholesterol-lowering, and anti-adipogenic bacterial strains from raw donkey's milk and homemade fermented pickles. Nine LAB strains with potential in vitro oxalate degrading, α-glucosidase inhibiting, and cholesterol-lowering activities were pre-screened from fourteen isolates. Further, the heat-killed cells of selected strains were evaluated for anti-adipogenic activity in murine 3T3-L1 adipocytes. This activity was examined by studying the lipid storage, gene, and protein expression of adipogenic and lipogenic transcription factors. Subsequently, four potential isolates demonstrated a significant reduction in lipid storage by limiting adipogenesis (reducing C/EBPα, PPARγ expression), lipid transportation (downregulating aP2 expression), and lipogenesis (reducing PLIN-1 expression). These effective isolates were characterized using 16S rRNA molecular sequencing, and were identified as closest relatives to the Enterococcus (RRLA5, RRLA1, and RRLD6) and Lactobacillus (RRLM2) genera. Further, they displayed good survivability under in vitro gastric conditions and non-haemolytic activity. Taken together, the live cells of effective isolates depicted significant in vitro oxalate degradation, and their heat-killed cells demonstrated anti-adipogenic activity through downregulating the adipogenesis and lipogenesis. Moreover, future preclinical animal model studies on the synergistic role of probiotics and their heat-killed cells in disease prevention through gut microbial modulation could provide evidence as a biotherapeutic agent.

Recently, sea cucumber has been an increasingly important marine invertebrate in the fields of EcoDevo and fisheries studies. After the discovery of Sulfitobacter pontiacus strain BL28, which is a growth-promoting probiotic bacteria isolated from blastula of Apostichopus japonicus, host-microbes interaction has become a major new focus of study to be unveiled. Previous genome assessments of the strain BL28 hypothesized involvements of cobalamin/B12 biosynthesis, type IV secretion system, polyhydroxybutyrate production, and sulfate metabolism for host growth promotions. Here, we performed A. japonicus host transcriptome after five weeks of supplementation with S. pontiacus BL28. Unexpectedly, the host transcriptome revealed significant gene regulations of the BL28 supplementation on the host lipid and chondroitin metabolisms and transcriptionally "rest" status of heat shock protein genes un-expressed. Physiological and environmental crossover by the S. pontiacus BL28 supplementation may trigger stress-free growth promotion in the host sea cucumber. These symbiotics-type probiotics could help herald the future eco-friendly aquaculture of sea cucumber.

Ants are distributed across the globe and there are currently over 14,000 described species. Due to the high diversity between species, ants are considered vital keystone species to many ecosystems. They provide basic ecosystem services such as: seed dispersal, soil bioturbation, decomposition, and pest control. Within these ecosystems ants form complex symbiotic relationships with plants, fungi, and bacteria. Studying the interaction between ants and their bacteria is important because of the crucial role that microbes play in the overall health of ants. Aphaenogaster Mayr, 1853, which is a globally distributed ant genus, remains understudied in terms of their bacterial community. This study aims to determine the taxonomic composition and abundance of the Aphaenogaster bacterial community and to determine if development stage and species impact the bacterial community composition. For this study, ants from several colonies were collected from the Gordon Natural Area in West Chester, Pennsylvania, USA. DNA was then extracted from the ants in all stages of development and the 16S rRNA gene was amplified and sequencing following the NGS amplicon approach. The findings from this study reveal that species and development stage have a significant impact upon the bacterial community composition and abundance of Aphaenogaster ants, and Wolbachia is highly associated with these ants.

Har Lake (HL) is in the northeastern basin of the Qinghai-Xizang Plateau (QTP), sits at an altitude of 4379 m, and is classified as a soda lake within a wetland ecosystem. Evaluating the archaeal and bacterial communities in HL could offer valuable insights into the biogeochemical cycling within plateau wetland lakes. Consequently, high-throughput sequencing of 16S rRNA genes was conducted in this study to assess the composition of HL microbial communities and their association with environmental factors. The HL archaeal communities comprised 5 phyla, 5 classes, and 30 genera, while the bacterial communities comprised 28 phyla, 52 classes, and 542 genera. The dominant archaeal phylum was Thaumarchaeota (30.30-93.07% relative abundances), followed by Woesearchaeota (6.79-67.78%), while the most abundant genus was Nitrososphaera (30.30-93.07%). The distribution of Nitrososphaera was significantly correlated with TN, Mg²⁺, and Ca²⁺ concentrations. Bacterial communities predominantly comprised the Proteobacteria phylum (59.33-74.70%), followed by Bacteroidetes (13.92-19.19%) and Firmicutes (0.69-9.60%). Dominant bacterial genera included halophilic hydrocarbon-degrading bacteria like Oleibacter (1.90-18.69%), Perlucidibaca (5.19-17.46%), and Thalassolituus (0.80-11.98%). The results suggest Nitrososphaera and Woesearchaeota may be key taxa involved in carbon and nitrogen biogeochemical cycling within HL. Additionally, the high abundances of halophilic hydrocarbon-degrading bacteria suggests that potential contamination of HL may have occurred due to frequent animal and human activities. Overall, this study provides valuable insights into the archaeal and bacterial community structures in high-altitude soda lake wetlands and their interactions with their unique environments.

The early innate host immune response is crucial in the susceptibility to tuberculosis (TB). This study aimed to investigate the potential role of Toll-interacting protein (TOLLIP), a negative regulator of the human innate immune response, and interleukin-10 (IL-10), an anti-inflammatory cytokine, in susceptibility to TB. The peripheral blood mononuclear cells of 30 active pulmonary TB patients and 30 healthy volunteers were included. TOLLIP mRNA expression levels, single nucleotide polymorphisms (SNPs) of the TOLLIP gene, such as rs5743899A/G and rs3750920C/T, and IL-10 -1082G/A SNP were detected using real-time PCR, PCR-restriction fragment length polymorphism (PCR-RFLP) and amplification refractory mutation system-PCR (ARMS-PCR), respectively. TOLLIP mRNA expression levels were significantly higher in TB patients than in healthy controls (expression fold difference = 2.72, the delta-delta Ct method, also known as the 2-∆∆Ct method). The heterozygous (GA) genotype of the IL-10 -1080G/A polymorphism was significantly predominant among the patient group (p = 0.02, Hardy-Weinberg equilibrium). However, the Kruskal‒Wallis analysis found no significant relationship between TOLLIP mRNA expression levels and SNPs. TOLLIP mRNA and IL-10 -1082G/A SNP were assessed as potential biomarkers to predict TB susceptibility. For more significant results, they should be examined with other negative regulators of innate immunity and other immune factors associated with susceptibility to TB. Our study is the first to investigate the association of TOLLIP polymorphisms and expression levels with TB susceptibility in Turkey.