International Microbiology最新文献

Carbapenem-resistant Enterobacter cloacae complex (CRECC) constitutes a global public health threat challenging clinical treatment and infection control, especially in low- and middle-income countries such as India. We analyzed the antimicrobial susceptibility, major β-lactamase genes, plasmid profiles, and genetic relatedness to understand the molecular epidemiology of CRECC clinical isolates (n = 44) in West Bengal, India, during 2021-2022. The majority (> 55%) of the isolates were resistant to fluoroquinolones, aminoglycosides, and co-trimoxazole, even > 20% for tigecycline and > 35% were extensively drug-resistant. Co-β-lactamase production was categorized into twenty-seven types, importantly NDM (84%), OXA-48 (40%), TEM (61%), CTX-M (46%), OXA-1 (55%), and MIR (27%). The NDM-1 and OXA-181 were major variants with the first observations of NDM-24 and -29 variants in India. Wide-range of plasmids (2 to > 212 kb) were harbored by the β-lactamase-producing isolates: small (91%), medium (27%), large (9%), and mega (71%). IncX3, ColE1, and HI2 were noted in about 30% of isolates, while IncF and R were carried by < 20% of isolates. The clonally diverse CRECC isolates were noted to cause cross-infections, especially at superficial site, bloodstream, and urinary-tract. This is the first molecular surveillance on CRECC in India. The study isolates serve as the dockyard of NDM, TEM, and CTX-M harboring a wide range of plasmids. The outcomes of the study may strengthen local and national policies for infection prevention and control practices, clarifying the genetic diversity among CRECC. Extensive genomic study may further intersect the relationships between these different plasmids, especially with their sizes, types, and antibiotic resistance markers.

Developing microbial consortiums is necessary for microbial enhanced oil recovery (MEOR) in heavy crude oil production. The aqueous phase of produced fluid has long been considered an ideal source of microorganisms for MEOR. However, it is recently found that rich microorganisms (including hydrocarbon-degrading bacteria) are present in the crude oil phase, which is completely different from the aqueous phase of produced fluid. So, in this study, the microbial consortia from the crude oil phase of produced fluids derived from four wells were enriched, respectively. The microbial community structure during passage was dynamically tracked, and the response of enriched consortia to successive disturbance of environmental factors was investigated. The results showed the crude oil phase had high microbial diversity, and the original microbial community structure from four wells was significantly different. After ten generations of consecutive enrichment, different genera were observed in the four enriched microbial consortia, namely, Geobacillus, Bacillus, Brevibacillus, Chelativorans, Ureibacillus, and Ornithinicoccus. In addition, two enriched consortia (eG1614 and eP30) exhibited robustness to temperature and oxygen perturbations. These results further suggested that the crude oil phase of produced fluids can serve as a potential microbial source for MEOR.

Programmed cell death (PCD) has been reported in Xanthomonas axonopodis pv. glycines (Xag) wild type earlier and was indirectly shown to be induced by metabolic stress; however, deciphering the key proteins regulating the metabolic stress remained unrevealed. In this study, transcriptomic and proteomic analyses were performed to investigate the prominent pathways, having a role in the induction of metabolic stress in Xag cells undergoing PCD. A comprehensive analysis of transcriptome and proteome data revealed the major involvement of metabolic pathways related to branched chain amino acid degradation, such as acyl-CoA dehydrogenase and energy-yielding, ubiquinol:cytochrome c oxidoreductase complex, in Xag cells undergoing PCD. Consequently, oxidative stress response genes showed major upregulation in Xag cells in PCD-inducing medium; however, no such upregulation was observed at the protein level, indicative of depleted protein levels under excessive stress conditions. Activation of stress response and DNA repair proteins was also observed in Xag cells grown in PCD-inducing medium, which is indicative of excessive cellular damage. Thus, the findings indicate that programmed cell death in Xag is an outcome of metabolic stress in nutrient condition not suitable for a plant pathogen like Xanthomonas, which is more acclimatised with altogether a different nutritional requirement predominantly having an enriched carbohydrate source.

Aliarcobacter spp. have been isolated from numerous food products at retail and from animal carcasses and feces at slaughter. The objectives of this study were as follows: (i) to isolate Aliarcobacter species from different slaughterhouses' samples and (ii) to detect genetic diversity, antibiotic resistance, biofilm ability, and putative virulence gene profiles of the isolates. A molecular investigation of antibiotic resistance and virulence factors was also conducted using polymerase chain reaction (PCR). Among 150 samples, a total of 22 (14.6%) Aliarcobacter spp. isolates were obtained, with varying levels of antibiotic resistance observed. The genes tetO, tetW, and gyrA were detected in 0%, 31.8%, and 27.2% of the isolates, respectively. All isolates were resistant to ampicillin, rifampin, and erythromycin, while tetracycline was found to be the most effective antibiotic, with 81.8% of the isolates showing susceptibility to it. All isolates (100%) harbored more than one of the nine putative virulence genes tested, with 18.1% of isolates carrying more than three. Regarding biofilm formation, 7 (31.8%) and 4 (18.1%) isolates were found to form strong and moderate biofilms, respectively, while one (4.5%) isolate was classified as a weak biofilm producer. ERIC-PCR band patterns suggested that the isolated Aliarcobacter spp. from slaughterhouses had different sources of contamination. These findings highlight the potential risk posed by pathogenic and multidrug-resistant Aliarcobacter spp. in food and the need for control measures throughout the food chain to prevent the spread of these strains. The results indicate that foods of animal origin and cattle slaughterhouses are significant sources of antimicrobial resistant Aliarcobacter.

Context: Pathogens can manipulate microbial interactions to ensure survival, potentially altering the functional patterns and microbiome assembly. The present study investigates how Anaplasma phagocytophilum infection affects the functional diversity, composition, and assembly of the Ixodes scapularis microbiome, with a focus on high central pathways-those characterized by elevated values in centrality metrics such as eigenvector, betweenness, and degree measures, in the microbial community.

Methods: Using previously published data from nymphs' gut V4 region's amplicons of bacterial 16S rRNA, we predicted the functional diversity and composition in control and A. phagocytophilum-infected ticks and inferred co-occurrence networks of taxa and ubiquitous pathways in each condition to associate the high central pathways to the microbial community assembly.

Results: Although no differences were observed concerning pathways richness and diversity, there was a significant impact on taxa and functional assembly when ubiquitous pathways in each condition were filtered. Moreover, a notable shift was observed in the microbiome's high central functions. Specifically, pathways related to the degradation of nucleosides and nucleotides emerged as the most central functions in response to A. phagocytophilum infection. This finding suggests a reconfiguration of functional relationships within the microbial community, potentially influenced by the pathogen's limited metabolic capacity. This limitation implies that the tick microbiome may provide additional metabolic resources to support the pathogen's functional needs.

Conclusions: Understanding the metabolic interactions within the tick microbiome can enhance our knowledge of pathogen colonization mechanisms and uncover new disease control and prevention strategies. For example, certain pathways that were more abundant or highly central during infection may represent potential targets for microbiota-based vaccines.

Sulfitobacter is a bacterium recognized for its production of AMP-independent sulfite oxidase, which is instrumental in the creation of sulfite biosensors. This capability underscores its ecological and economic relevance. In this study, we present a newly discovered phage, Sulfitobacter phage vB_SupP_AX, which was isolated from Maidao of Qingdao, China. The vB_SupP_AX genome is linear and double-stranded and measures 75,445 bp with a GC content of 49%. It encompasses four transfer RNA (tRNA) sequences and 79 open reading frames (ORFs), one of which is an auxiliary metabolic gene encoding thioredoxin. Consistent with other N4-like phages, vB_SupP_AX possesses three distinct RNA polymerases and is characterized by the presence of four tRNA molecules. Comparative genomic and phylogenetic analyses position vB_SupP_AX and three other viral genomes from the Integrated Microbial Genomes/Virus v4 database within the Rhodovirinae virus subfamily. The identification of vB_SupP_AX enhances our understanding of virus-host interactions within marine ecosystems.

Fabrics act as fomites for microorganisms, thereby playing a significant role in infection transmission, especially in the healthcare and hospitality sectors. This study aimed to examine the biofilm formation ability of four nosocomial infection-causing bacteria (Acinetobacter calcoaceticus, Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) on cotton, polyester, polyester-cotton blend, silk, wool, viscose, and nylon, used frequently in the healthcare sector, by qualitative and quantitative methods. The impact of temperature, pH, and relative humidity (RH) on biofilm formation was also assessed. P. aeruginosa and S. aureus were strong biofilm producers, while E. coli produced weak biofilm. Wool (maximum roughness) showed the highest bacterial load, while silk (lowest roughness) showed the least. P. aeruginosa exhibited a higher load on all fabrics, than other test bacteria. Extracellular polymeric substances were characterized by infrared spectroscopy. Roughness of biofilms was assessed by atomic force microscopy. For biofilm formation, optimum temperature, pH, and RH were 30 °C, 7.0, and 62%, respectively. MgCl₂ and CaCl₂ were the most effective in removing bacterial biofilm. In conclusion, biofilm formation was observed to be influenced by the type of fabric, bacteria, and environmental conditions. Implementing recommended guidelines for the effective disinfection of fabrics is crucial to curb the risk of nosocomial infections. In addition, designing modified healthcare fabrics that inhibit pathogen load could be an effective method to mitigate the transmission of infections.

Background: Synthetic algal-fungal and algal-bacterial cultures have been investigated as a means to enhance the technological applications of the algae. This inclusion of other microbes has enhanced growth and improved stress tolerance of the algal culture. The goal of the current study was to investigate natural microbial consortia to gain an understanding of the occurrence and benefits of these associations in nature. The photosynthetic protist Euglena mutabilis is often found in association with other microbes in acidic environments with high heavy metal (HM) concentrations. This may suggest that microbial interactions are essential for the protist's ability to tolerate these extreme environments. Our study assessed the Cd tolerance of a natural fungal-algal-bacterial (FAB) association whereby the algae is E. mutabilis.

Results: This study provides the first assessment of antibiotic and antimycotic agents on an E. mutabilis culture. The results indicate that antibiotic and antimycotic applications significantly decreased the viability of E. mutabilis cells when they were also exposed to Cd. Similar antibiotic treatments of E. gracilis cultures had variable or non-significant impacts on Cd tolerance. E. gracilis also recovered better after pre-treatment with antibiotics and Cd than did E. mutabilis. The recoveries were assessed by heterotrophic growth without antibiotics or Cd. In contrast, both Euglena species displayed increased chlorophyll production upon Cd exposure. PacBio full-length amplicon sequencing and targeted Sanger sequencing identified the microbial species present in the E. mutabilis culture to be the fungus Talaromyces sp. and the bacterium Acidiphilium acidophilum.

Conclusion: This study uncovers a possible fungal, algal, and bacterial relationship, what we refer to as a FAB consortium. The members of this consortium interact to enhance the response to Cd exposure. This results in a E. mutabilis culture that has a higher tolerance to Cd than the axenic E. gracilis. The description of this interaction provides a basis for explore the benefits of natural interactions. This will provide knowledge and direction for use when creating or maintaining FAB interactions for biotechnological purposes, including bioremediation.

We determined whether there exists a complementary pathway of cordycepin biosynthesis in wild-type Cordyceps militaris, high-cordycepin-producing strain C. militaris GYS60, and low-cordycepin-producing strain C. militaris GYS80. Differentially expressed genes were identified from the transcriptomes of the three strains. Compared with C. militaris, in GYS60 and GYS80, we identified 145 and 470 upregulated and 96 and 594 downregulated genes. Compared with GYS80, in GYS60, we identified 306 upregulated and 207 downregulated genes. Gene Ontology analysis revealed that upregulated genes were mostly involved in detoxification, antioxidant, and molecular transducer in GYS60. By Clusters of Orthologous Groups of Proteins and Kyoto Encyclopedia of Genes and Genomes analyses, eight genes were significantly upregulated: five genes related to purine metabolism, one to ATP production, one to secondary metabolite transport, and one to RNA degradation. In GYS60, cordycepin was significantly increased by upregulation of ATP production, which promoted 3',5'-cyclic AMP production. Cyclic AMP accelerated 3'-AMP accumulation, and cordycepin continued to be synthesized and exported. We verified the novel complementary pathway by adding the precursor adenosine and analyzing the expression of four key genes involved in the main pathway of cordycepin biosynthesis. Adenosine addition increased cordycepin production by 51.2% and 10.1%, respectively, in C. militaris and GYS60. Four genes in the main pathway in GYS60 were not upregulated.

Soil salinity has been one of the significant barriers to improving rice production and quality. According to reports, Bacillus spp. can be utilized to boost plant development in saline soil, although the molecular mechanisms behind the interaction of microbes towards salt stress are not fully known. Variations in rice plant protein expression in response to salt stress and plant growth-promoting rhizobacteria (PGPR) inoculations were investigated using a proteomic method and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Findings revealed that 54 salt-responsive proteins were identified by mass spectrometry analysis (LC-MS/MS) with the Bacillus spp. interaction, and the proteins were functionally classified as gene ontology. The initial study showed that all proteins were labeled by mass spectrometry analysis (LC-MS/MS) with Bacillus spp. interaction; the proteins were functionally classified into six groups. Approximately 18 identified proteins (up-regulated, 13; down-regulated, 5) were involved in the photosynthetic process. An increase in the expression of eight up-regulated and two down-regulated proteins in protein synthesis known as chaperones, such as the 60 kDa chaperonin, the 70 kDa heat shock protein BIP, and calreticulin, was involved in rice plant stress tolerance. Several proteins involved in protein metabolism and signaling pathways also experienced significant changes in their expression. The results revealed that phytohormones regulated the manifestation of various chaperones and protein abundance and that protein synthesis played a significant role in regulating salt stress. This study also described how chaperones regulate rice salt stress, their different subcellular localizations, and the activity of chaperones.