Archives of Microbiology最新文献

Antimicrobial resistance (AMR) in Acinetobacter baumannii represents a critical global health challenge, particularly in intensive care settings where the pathogen causes severe, refractory infections. As a leading member of the ESKAPE group, A. baumannii has accumulated extensive resistance to multiple antibiotic classes, including carbapenems, resulting in the widespread emergence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) strains. This review provides a chronological overview of the evolution of antimicrobial therapies used against A. baumannii, spanning the early era of penicillins and tetracyclines to contemporary agents such as eravacycline and ceftazidime–avibactam. We delineate the molecular mechanisms underlying resistance development, including carbapenemase production, robust RND efflux systems, horizontal gene transfer, biofilm formation, and the global dissemination of high-risk international clones (IC1–IC9). The compounding impact of the COVID-19 pandemic on the spread of carbapenem-resistant A. baumannii (CRAB) is also examined. A special emphasis is placed on Zosurabalpin, a first-in-class macrocyclic peptide antibiotic with a unique mechanism of action that targets the LptB₂FG complex essential for lipooligosaccharide (LOS) transport and outer membrane assembly. Preclinical data and emerging clinical findings highlight its potent activity against highly resistant CRAB strains and its ability to circumvent conventional resistance pathways, marking it as a promising candidate in the antimicrobial pipeline. Finally, we evaluate the limitations of current treatment modalities and explore emerging strategies, including phage therapy, novel target discovery, and non-traditional therapeutics, offering a forward-looking perspective on restoring and sustaining effective anti-Acinetobacter interventions.

Probiotics are live microorganisms that confer health benefits when administered in adequate amounts, enhance immune function, promote gut health, and are increasingly recognized as effective alternatives to antibiotics for improving animal health and productivity. This study investigated the probiotic potential of lactic acid bacteria (LAB) from Mystus cavasius through morphological, physiological, and molecular characterization for aquaculture feed applications. Out of twenty-two presumptive LAB isolates, eleven were sequenced after biochemical screening, and molecular analysis confirmed eight as LAB (Weisella confusa ML1, ML2, ML3, ML6, ML7; Enterococcus faecalis ML8, ML9; Lactococcus garvieae ML10). The study also found a potential non-LAB probiotic bacterium Bacillus subtilis ML4. Moreover, the study identified Paraburkholderia phytofirmans, a potential plant probiotic bacterium, for the first time in fish. Among the identified LAB isolates, L. garvieae ML10 was excluded from probiotic potential assessments because of its reported disease-causing potential and associated health risks. All the tested LAB isolates were found to tolerate acidic pH (2–5) and bile salts (2.5–7.5%), indicating their probiotic potential for aquaculture applications. Additionally, the isolates showed no hemolytic activity and demonstrated strong probiotic potential, characterized by high cell surface hydrophobicity, ranging from 41.98 ± 16.68% to 62.19 ± 4.09% in xylene and 51.58 ± 1.67% to 64.83 ± 4.91% in toluene, robust autoaggregation (55.51 ± 3.63% to 64.33 ± 2.87%) and substantial coaggregation with Staphylococcus haemolyticus (46.27 ± 2.96% to 53.54 ± 0.72%) and Bacillus cereus (34.34 ± 3.16% to 51.76 ± 4.08%). Furthermore, they exhibited potent in vitro inhibitory effects against the fish pathogens Aeromonas veronii and L. garvieae and revealed susceptibility to several commonly used antibiotics. Therefore, the results revealed that the selected LAB isolates might be ideal probiotic candidates to be used in sustainable aquaculture practices.

The bacterial pathogen Acinetobacter baumannii is an opportunistic and nosocomial causative agent of multidrug resistant infections worldwide. The present study conducted comparative genomic analyses to identify relevant pathogenicity traits in A. baumannii strains from diverse clinical samples and geographical regions in Mexico. Pangenome analysis clustered the strains into four phylogenomic clades, comprising various international clones. Clades I and II strains, predominantly from blood and respiratory infections in the Central region, were significantly associated with the Latin American IC5 clone (P = 0.0002), whereas clade III strains, primarily from diverse samples in the Northwestern region, were significantly associated with the European IC2 clone (P = 0.0030). Virulence determinants implicated in adhesion (ompA, omp38), biofilm formation (pgaA-D, csuA/BABCDE), motility (pil, fim), regulatory systems (bfmRS, barAB, abaR/abaI), iron acquisition (bas, bau), and efflux pump-delivery systems (adeFGH) were identified among the A. baumannii strains, representing all clades and geographical regions. Analysis of intrinsic and acquired antimicrobial resistance revealed that clades I and II strains were significantly correlated with resistance to β-lactamases (blaADC-6, blaOXA-239, blaOXA-65), sulfonamides (sul2), and chloramphenicol (cmlB1) (P = 0.0001). Interestingly, clade III strains, predominantly from the agricultural Northwestern region, exhibited a significant association of broader resistance genes against aminoglycosides (aac(6’)-Ib’, aph(3’)-Ia, armA, aadA), β-lactamases (blaTEM-4, blaADC-25, blaOXA-66), sulfonamides (sul1), tetracyclines (tetA), and macrolides (mphD, msrE) (P = 0.0001). Subsequent characterization of mobile genetic elements indicated genetic plasticity and potential transfer of antimicrobial resistance. Collectively, this fundamental information would enable the improvement of epidemiological surveillance and intervention strategies for A. baumannii.

Resorcine-based macrocycles have received significant attention in drug delivery applications owing to their tunable functional groups, well-defined cavities, and inherent self-assembly behavior, considering essential for encapsulation and controlled release of loaded drug candidates. However, existing resorcinarene derivatives face certain limitations in drug loading, physiologic stability, and compatibility with structurally complex natural therapeutics, necessitating the development of novel macrocyclic architectures with improved stability and compatibility for hydrophobic drugs. To address this gap, the current research synthesized a novel resorcinarene-based macrocycle, referred to as Indole Macrocycle (IM), to improve the therapeutic potential of quercetin (QTN). The synthesized IM was characterized utilizing Mass, ¹H- and ¹³C-NMR, and FT-IR spectroscopy. Biocompatibility studies indicated high cell viability of NIH-3T3 cells at 30 µM (95.72 ± 0.4% at 24 h and 94.10 ± 0.3% at 48 h) and low hemolytic activity (9.32% ± 1.65% at 1000 µg/mL). The critical micelle concentration (CMC) of IM was determined to be 0.022 mM. QTN-loaded IM vesicles exhibited a spherical morphology with a size of 248.7 ± 7.17 nm, zeta potential of − 15.8 ± 0.8 mV, PDI of 0.258 ± 0.05, and encapsulation efficiency of 74 ± 2.57%, while demonstrating a controlled drug release profile, with maximum release of 69% ± 1.8% over 48 h. Antibacterial evaluation against multidrug-resistant S. aureus strains (NCTC 13143 and NCTC 13277) revealed a significantly reduced MIC of 170 ± 8.23 µg/mL compared to 488 ± 9.53 µg/mL for free QTN. The results were further confirmed through AFM analysis, demonstrating significant bacterial membrane disruption following treatment. These findings revealed that QTN-loaded IM vesicles are a promising system for improving drug delivery and combating MDR bacterial infections.

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Alcanivorax borkumensis is a key marine hydrocarbon-degrading bacterium with the potential to clean up oil spills from the sea and protect marine ecosystems. The accidental release of crude oil and other oil products is a major concern for the environment, as it has detrimental effects on marine life. Several strains of A. borkumensis have been isolated from a variety of different marine habitats, such as temperature, deep-sea and polar regions, with pathways of alkane degradation, as well as strain-specific genetic adaptations in the areas of hydrocarbon use, nutrient uptake, and resistance to adverse environmental conditions. Among these, A. borkumensis SK2 strain has been widely characterised as the model organism, giving extensive information on the genomic, metabolic, and physiological foundations of efficient alkane degradation. The genetic features of SK2 help explain its efficiency towards biodegradation and its overall contribution towards environmental recovery following hydrocarbon contamination. This article is a review of the current knowledge on the ecological importance, genetic structure, and biodegradation of the alkane hydroxylase-containing A. borkumensis, focusing on alkane hydroxylase systems, biosurfactant synthesis, biofilms and nutrient scavenging probability. These findings highlight the potential of increasing Alcanivorax catabolic activities in the wake of an oil spill to mitigate the environmental disaster effects. Further functional analysis of the genes and proteins of A. borkumensis is essential for achieving its biotechnological and ecological potential in marine hydrocarbon remediation.

Vancomycin is a critical glycopeptide antibiotic for treating severe infections caused by Gram-positive bacteria, particularly MRSA and Clostridioides difficile, by inhibiting cell wall synthesis through binding to D-Ala–D-Ala termini of peptidoglycan precursors. Resistance has emerged in Enterococcus spp (VRE) and Staphylococcus spp, (VISA/VRSA) through acquisition of van operons, precursor modification (D-Ala-D-Lac/D-Ser), cell wall thickening, biofilm formation, and regulatory mutations, leading to treatment failures and increased morbidity. Global genomic surveillance reveals ongoing clonal expansion and horizontal spread of resistance determinants. This review comprehensively examines vancomycin’s mechanism of action, the evolutionary emergence and genetic basis of resistance, adaptive survival strategies of pathogens, clinical/epidemiological consequences, current alternative therapies, and precision stewardship approaches including area under the concentration–time curve/minimum inhibitory concentration (AUC/MIC)-guided therapeutic drug monitoring (TDM). Most importantly, it highlights the transformative and still under-appreciated role of artificial intelligence in overcoming vancomycin resistance: machine learning accelerates discovery of novel antimicrobial peptides and repurposed drugs, AI-driven surveillance enables real-time resistance detection and outbreak forecasting, and hybrid AI-molecular modeling rationally designs superior vancomycin derivatives with enhanced activity against VRE and VRSA. These rapidly evolving AI-integrated strategies, when combined with strengthened infection control and stewardship, offer the most promising path forward to preserve and extend the clinical utility of vancomycin and related antibiotics.

Aflatoxins and ochratoxins are highly potent mycotoxins primarily produced by Aspergillus and Penicillium species, contaminating various agricultural commodities, especially cereals, nuts, and animal feeds. Chronic exposure to these mycotoxins is associated with liver cancer, immunosuppression, and developmental disorders, posing significant risks to public health and socioeconomic stability in numerous developing countries. Detoxification of mycotoxins has traditionally depended on physical and chemical methods, which exhibit limitations such as partial efficacy, nutrient loss, changes in food quality, high energy requirements, and environmental issues. Biological detoxification has recently garnered significant attention as a sustainable, safe, and eco-friendly alternative. This method utilises microorganisms, including bacteria, yeast, and fungi, along with their enzymes and metabolites, to transform mycotoxins into less toxic or non-toxic compounds, while maintaining the nutritional and sensory quality of food and feed. This review systematically analyses the recent advancements in the understanding of the microbiological and enzymatic mechanisms of aflatoxin (AFB) and ochratoxin (OTA) degradation. It emphasises the function of essential enzymes such as aldehyde dehydrogenase, amidohydrolase, carboxypeptidases, laccases, manganese peroxidases and oxidases, transforming AFB₁ and OTA into less toxic compounds like AFD₁, AFQ_1, L-β-phenylalanine and OTα. Industrial applications of these enzymes in feed and food processing are discussed. Contemporary challenges, including incomplete degradation, the formation of unknown by-products, and the variability of enzyme performance across different food matrices, are reviewed. The review proposes strategic approaches to enhance biological detoxification efficiency. These insights provide a framework for developing scalable, safe, and effective biotechnology solutions to mitigate mycotoxin contamination in the global food chain.

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It involves the combination of microbiology and civil engineering offering a revolutionary way of sustainable construction. The review shows that potential of microbial processes to increase material durability and decrease environmental impact is highly promising. One of the most notable inventions is microbially induced calcium carbonate precipitation (MICP), that can enhance the strength of the soil and concrete up to 50 percent and self-heal qualities, increasing the service life of infrastructures significantly. Microbial technologies are also providing effective means to remediate contaminated construction sites and waste management to provide cleaner ecosystems. Besides, the use of microorganisms in the treatment of wastewater in infrastructure projects reduces environmental footprints. Such synergy is interdisciplinary, hence covering key issues of material degradation and wastes, but also leading to greener built environments. The development of biocementation, self-healing concrete and microbial corrosion inhibition highlights the importance of microbiology in improving sustainable civil engineering activities.

Microorganisms and their derivative by-products are among the renewable energy sources in ecologically sustainable systems. In this study, four pectin-degrading bacterial strains were isolated from oil-contaminated agricultural soil. Strain SA2 produced the maximum enzyme index, measuring of 20 mm, and exhibited extracellular pectinase enzyme activity of 119.67 U/mL. The strain was identified as Bacillus infantis through 16S rRNA gene sequencing. Using a one-factor-at-a-time approach, B. infantis (SA2) demonstrated the highest enzyme activity (U/mL) at 180 at 40 °C, 172 at pH 8.0, 187 with 1.5% glucose, and 174 with 1% ammonium sulfate. RSM optimized with five variables, viz., temperature 37.5 °C, pH 8.5, glucose 0.5%, ammonium sulfate 1.5%, and incubation time 24 h, predicted a pectinase yield of 268 U/mL. Under such optimized conditions, the partially optimized protein was characterized through SDS-PAGE, which revealed a characterization by molecular weight of 40 kDa. Nine major peptide peaks from pectinase protein were identified through mass fingerprinting. Of these, the peptide IAIDPIQGVDEAKAR, with a mass-to-charge ratio of 595 and a peak area of 6321, exhibited a maximum error (ppm) of 6321 of − 68.46. We made a homology modeling structure of the pectinase-producing enzyme, and molecular studies demonstrated its ability to degrade agricultural pesticides with a binding affinity of − 6.3 kcal/mol. Overall, B. infantis (SA2) is a good source of pectinase-producing strain and represents a valuable resource for industrial purposes, promising biotechnological biofertilizer applications, including in the agricultural sector.

Inflammatory bowel disease (IBD) is a globally wide spread chronic disease with remittent attacks. It causes many stressful symptoms which decrease the quality of life of the patients remarkably. IBD requires long term treatment due to its chronic nature. Probiotics are promising treatment approach for IBD due to its improve of the composition of the gut microbiota which have a great role in the development of colitis, in addition to its safety on the long term use in comparison to traditional treatment options. A novel promising Lactiplantibacillus strain, with superior probiotic potential, is tested for the management of colitis. Colitis was induced in different mice groups using dextran sodium sulphate. One group is treated by a commercial probiotic preparation, another group was treated with sulfasalazine and the last group was treated by the novel Lactiplantibacillus strain. Inflammation was assessed by measuring pro-inflammatory markers such as IL-6, IL1-β and TNF-α. Oxidative stress was determined by measuring, Catalase and SOD activities in addition to malondialdehyde level. The effect of Lactiplantibacillus strain on the intestinal barrier function was examined by measuring the expression levels of tight junction proteins of claudin1, occludin and zonula occludens1 in mice colon and CaCo2 cell line. The novel Lactiplantibacillus strain significantly decreased the inflammatory markers level and oxidative stress. It also strengthens the intestinal barrier by increasing the expression of tight junction proteins in colon tissue and CaCo2 cell line. The effect of the novel Lactiplantibacillus strain was comparable to sulfasalazine and over performed commercial probiotic preparation.