Archives of Microbiology最新文献

{"title":"Association between a carbapenem post-prescription audit and gram-negative susceptibility: a 6-year time-series analysis","authors":"Fazlollah Keshavarzi,&nbsp;Sanjay Rampal,&nbsp;Chiu Wan Ng,&nbsp;Koo Koon Lim,&nbsp;Soo Nee Tang,&nbsp;Sasheela Sri La Sri Ponnampalavanar","doi":"10.1007/s00203-026-05154-4","DOIUrl":"10.1007/s00203-026-05154-4","url":null,"abstract":"<div><p>Antimicrobial stewardship programs (ASPs) are critical for combating antimicrobial resistance (AMR), yet their longitudinal ecological impacts remain debated. This study evaluated the association between a carbapenem post-prescription audit and the susceptibility of seven Gram-negative bacteria over 6 years. A retrospective interrupted time-series (ITS) study was conducted in a tertiary hospital, comparing pre-implementation (2015–2017) and post-implementation (2018–2020) phases. Autoregressive Integrated Moving Average (ARIMA) modeling was utilized to assess trend modifications and immediate level changes in pathogen susceptibility before and after audit enforcement. The audit was associated with pathogen-specific trend reversals. <i>Proteus mirabilis</i> imipenem susceptibility reversed from a significantly declining baseline to a positive recovery trend post-intervention (β = 9.465, <i>P</i> = 0.005). Conversely, <i>Klebsiella pneumoniae</i> and <i>Pseudomonas aeruginosa</i> experienced significant downward post-intervention trend reversals for targeted carbapenems despite rising baselines. Ecologically, immediate susceptibility gains in third-generation cephalosporins for <i>Acinetobacter baumannii</i> and <i>Escherichia coli</i> contrasted with significant collateral susceptibility declines for fluoroquinolones and β-lactam/ β-lactamase inhibitors, including a severe immediate drop in <i>P. mirabilis</i> susceptibility to amoxicillin-clavulanate (β = − 43.023, <i>P</i> = 0.024). While targeted carbapenem audits are temporally associated with the reversal of specific declining susceptibility trajectories, they may also coincide with the displacement of selective pressure onto broad-spectrum alternatives. Comprehensive ASPs must concurrently monitor total institutional antibiograms to identify and manage this potential ecological displacement.</p></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149103327","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geraniol attenuates Streptococcus mutans biofilm and virulence as an anti-caries agent","authors":"Yasaman Hariri,&nbsp;Majid Akbari,&nbsp;Zahra Alimardan,&nbsp;Zahra Chegini,&nbsp;Aref Shariati","doi":"10.1007/s00203-026-05241-6","DOIUrl":"10.1007/s00203-026-05241-6","url":null,"abstract":"<div><p><i>Streptococcus mutans</i>-induced dental caries is largely mediated by robust biofilm formation, making it notoriously difficult to treat with conventional antimicrobials. To overcome the limited efficacy and penetration challenges associated with current conventional treatments, this study investigated the in vitro and in silico effects of geraniol on <i>S. mutans</i> biofilm and the expression of genes associated with biofilm formation. Antibacterial activity was evaluated using disk diffusion and minimum inhibitory concentration (MIC) assays. Membrane integrity, anti-biofilm activity, and structural alterations were assessed through intracellular protein and nucleic acid leakage analyses, biofilm eradication assays, and scanning electron microscopy (SEM), respectively. Quantitative real-time PCR (qRT-PCR) was used to analyze the expression of biofilm-associated genes. Molecular docking was performed to investigate interactions between geraniol and major <i>S. mutans</i> biofilm -related proteins. Geraniol exhibited marked antibacterial activity against <i>S. mutans</i> isolates, with inhibition zone diameters of 12.0 ± 0.0 mm and a MIC value of 107 µg/mL. Treatment induced significant leakage of intracellular proteins and nucleic acids, indicating disruption of membrane integrity. Exposure to 4×MIC markedly impaired mature biofilm architecture. SEM analysis confirmed severe morphological damage, including membrane disruption and cellular deformation. qRT-PCR analysis demonstrated significant downregulation of the biofilm-associated genes <i>gtfB</i>,<i> gtfC</i>,<i> and gtfD</i> following treatment with geraniol. Molecular docking further revealed stable interactions between geraniol and key biofilm regulatory proteins, including GtfB, GtfC, and GtfD. These findings highlight the ability of pure geraniol to dismantle both the structural integrity and genetic machinery of the bacteria, supporting its potential as a novel therapeutic candidate against biofilm-mediated oral infections.</p></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149103372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bioconversion of macroalgae by enzymes from associated fungi into hydrolysates with cumulative antioxidant and antiglycemic properties for effective diabetes management","authors":"Ashok Shivaji Jagtap,&nbsp;Ajith Chandrasekar,&nbsp;Cathrine Sumathi Manohar,&nbsp;Ashutosh Shankar Parab,&nbsp;R. Rajyashree,&nbsp;Nagaraj P. Vijay Sankar","doi":"10.1007/s00203-026-05232-7","DOIUrl":"10.1007/s00203-026-05232-7","url":null,"abstract":"<div><p>Enzyme-assisted extraction is an emerging sustainable alternative to solvent based methods for recovering bioactive molecules from seaweed or macroalgal biomass. This study investigated the macroalgae-associated fungi as sources of extracellular enzymes for bioconversion of macroalgal biomass and the concurrent enhancement of bioactive properties. About 100 fungal isolates associated with macroalgae were isolated and characterized based on qualitative plate assays and quantitative enzyme activity for the production of cellulase, xylanase, agarase, alginate lyase, and ulvan lyase. Based on enzyme activity ranging from 1063 to 10,234 U ml^− 1, four yeast isolates and one filamentous fungus were selected for solid-state fermentation of macroalgae <i>Gracilaria corticata</i>, <i>Sargassum cinereum</i> and <i>Chaetomorpha antennina.</i> The biochemical composition of reducing sugar, total phenolic and protein content in the seaweed hydrolysates obtained from solid state fermentation was significantly higher than the uninoculated control. The enzymatic hydrolysates of all the three macroalgal biomass, exhibited almost twice the antioxidant activity than its non-enzymatic control. However, antiglycemic activity was observed only in <i>S. cinereum</i> hydrolysate which ranged about 20 to 40%, which was significantly higher than the control. Significant correlation between the biochemical constituents and antioxidant activity was observed in the enzymatic hydrolysates of <i>G. corticata</i>, <i>S. cinereum</i> and <i>C. antennina</i>. Positive correlation was also observed between the protein content with antioxidant and antiglycemic activity in the hydrolysate of <i>S. cinereum.</i> This shows that the microbial enzymes have the potential for the bioconversion of macroalgal biomass, into bioactive molecules for sustainable diabetes management and for related health care applications.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149103315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antagonistic responses of native Trichoderma spp. vary among Bipolaris sorokiniana isolates","authors":"Gabriela Pupo Hagemeyer,&nbsp;Simone Cristine Izidoro-Morimitsu,&nbsp;Cacilda Marcia Duarte Rios Faria,&nbsp;Jackson Kawakami,&nbsp;Paulo Roberto Da-Silva,&nbsp;Felipe Liss Zchonski,&nbsp;Adriana Knob","doi":"10.1007/s00203-026-05225-6","DOIUrl":"10.1007/s00203-026-05225-6","url":null,"abstract":"<div><p>Spot blotch caused by <i>Bipolaris sorokiniana</i> is a major threat to barley production worldwide. Although the genus <i>Trichoderma</i> is widely recognized for its biocontrol potential, the extent to which genetic diversity among distinct pathogen isolates influences antagonistic responses remains poorly understood. This study screened eight native <i>Trichoderma</i> isolates from threatened Araucaria Forest remnants against six <i>B. sorokiniana</i> field isolates using exclusively in vitro assays. Pathogen genetic diversity was assessed using inter-simple sequence repeat (ISSR) markers, while biocontrol potential was evaluated through dual culture and volatile/non-volatile metabolite production. Nei’s genetic diversity (<i>h</i> = 0.444) and Shannon’s information index (<i>I</i> = 0.634) revealed high genetic diversity among <i>B. sorokiniana</i> isolates, with no obvious relationship to sampling location. Our results showed that the antagonistic efficacy of <i>Trichoderma</i> varied according to the <i>B. sorokiniana</i> isolate. Although all <i>Trichoderma</i> isolates inhibited pathogen growth, their performance was highly isolate-dependent: the commercial standard <i>T. harzianum</i> exhibited the highest inhibition (up to 94%), followed by the native isolates <i>T. harzianum</i> LMA A14 and <i>T. azevedoi</i> LMA A22 (up to 82%) in dual culture, whereas <i>T. asperelloides</i> (LMA A20 and LMA A24) and <i>T. longibrachiatum</i> LMA A21 excelled differentially in volatile and non-volatile metabolite production, showing distinct suppression profiles across different <i>B. sorokiniana</i> genotypes. This study suggests that microbial biocontrol is a dynamic interaction in which variability among pathogen isolates may influence antagonist performance, highlighting the importance of evaluating a range of them when screening broad-spectrum native biocontrol candidates for sustainable disease management.</p></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00203-026-05225-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035458","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring biochar-mediated remediation of tetracycline-contaminated soil via a metagenomic approach: insights into soil microbial community and potential functions","authors":"Jiahui Zhang,&nbsp;Xiaoyan Cao,&nbsp;Lod Fabuleux Tresor Baniakina,&nbsp;Lihong Chai","doi":"10.1007/s00203-026-05230-9","DOIUrl":"10.1007/s00203-026-05230-9","url":null,"abstract":"<div><p>Biochar is widely used as a soil amendment; however, information regarding its effects on soil microbial communities under tetracycline (TET) stress remains limited. In this study, metagenomic sequencing was employed to investigate the effects of TET contamination and biochar amendment on soil microbial community profiles, the abundance of antibiotic resistance genes (ARGs), and carbohydrate-active enzymes (CAZymes) genes through a pot experiment. Results showed that TET exposure reduced microbial diversity and evenness, and significantly altered the relative abundance of dominant microbes (e.g., Acidobacteriota and <i>Candidatus_Rokubacteria</i>) whereas biochar amendment especially at 0.5% application significantly increased both diversity and evenness, facilitated the recovery of dominant microbes, and improved community stability. TET exposure also enriched glycopeptide resistance genes and shifted CAZyme gene profiles. Overall, the metagenomic results demonstrated that reed biochar can regulate soil microbial responses under TET stress, providing insights into its role in alleviating antibiotic-induced microbial disturbance and supporting soil ecological resilience.</p></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Halotolerant plant growth-promoting bacteria isolated from Opuntia dillenii (Ker Gawl) Haw (Cactaceae) may enhance tomato growth under salinity stress in greenhouse conditions","authors":"Yves Kévin Brun,&nbsp;Agossou Damien Pacôme Noumavo,&nbsp;Julien Colombet,&nbsp;Sibel Turali,&nbsp;Lamine Baba-Moussa,&nbsp;François Lefort","doi":"10.1007/s00203-026-05229-2","DOIUrl":"10.1007/s00203-026-05229-2","url":null,"abstract":"<div><p>High soil salinity constrains global agricultural productivity, necessitating effective mitigation strategies. Plant growth-promoting bacteria (PGPB) offer a promising approach to enhance crop salt tolerance. This study evaluated halotolerant bacteria from <i>O. dillenii</i> to improve tomato (<i>Solanum lycopersicum</i> L.) growth under salinity. Bacteria from plant organs and rhizosphere were screened at 0–3 M NaCl; 52.38% grew above 1.5 M, and six strains—<i>P. flexa</i> S4, S6, R7, C5; <i>B. amyloliquefaciens</i> R4; and <i>M. yunnanensis</i> C11—tolerated up to 2.5 M. Under 120 mM NaCl, biopriming with <i>P. flexa</i> S6 and C5 increased germination to 75% and vigor index by 149.2%. Under 200 mM NaCl, <i>P. flexa</i> S6 boosted root biomass by 167.5%, C5 improved root length and diameter by 25.6% and 30.98%, and R7 enhanced shoot growth while reducing leaf proline by 78%. These selected strains effectively alleviate salt stress and promote tomato growth, promising an application in sustainable agricultural systems.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00203-026-05229-2.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pharmaceutical innovation in advanced nanomedicine for the treatment of hypervirulent and multidrug-resistant Klebsiella pneumoniae infections","authors":"Helal F. Hetta,&nbsp;Fawaz E. Alanazi,&nbsp;Hanan Alshareef,&nbsp;Ghareb M. Soliman,&nbsp;Sultan A. Almadi,&nbsp;Ageel F. Aljuhani,&nbsp;Salwa Qasim Bukhari,&nbsp;Zinab Alatawi,&nbsp;Noura H. Abd Ellah,&nbsp;Ali M. Atoom,&nbsp;Mahmoud El-Maghrabey,&nbsp;Yasmin N. Ramadan","doi":"10.1007/s00203-026-05194-w","DOIUrl":"10.1007/s00203-026-05194-w","url":null,"abstract":"<div><p>Hypervirulent and multidrug-resistant <i>Klebsiella pneumoniae</i> represents a dual threat to global health, combining aggressive virulence with resistance to last-line antibiotics. Conventional therapies are failing, leaving an urgent need for disruptive approaches. Nanotechnology offers transformative solutions by enabling targeted drug delivery, dismantling biofilms, restoring antibiotic potency, and introducing novel modalities such as phage–nanoparticle hybrids and CRISPR-based nanoplatforms. This review synthesizes recent advances in metal-, polymer-, and lipid-based nanostructures designed to combat hvKp, highlighting mechanisms of action, synergistic combinations with antibiotics, and innovative theranostic systems. We also critically examine translational challenges, including reproducibility, safety, and regulatory uncertainty, while outlining future opportunities for precision nanomedicine through smart nanoplatforms, nano-enabled diagnostics, and AI-driven design. By integrating efficacy with safety and clinical feasibility, nanotechnology holds promise to reshape the therapeutic landscape for hvKp and MDR pathogens and contribute to broader strategies against antimicrobial resistance.</p></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Harnessing phage-ciprofloxacin synergy to overcome multidrug-resistant infections and biofilm persistence","authors":"Nashath Kalangadan,&nbsp;Srivignesh Sundaresan,&nbsp;Abishek Mani,&nbsp;Nandhakumar Muruganandham,&nbsp;Siji Siju,&nbsp;Sutharsan Govindarajan,&nbsp;Kaushik Rajaram","doi":"10.1007/s00203-026-05223-8","DOIUrl":"10.1007/s00203-026-05223-8","url":null,"abstract":"<div><p><i>Enterococcus faecalis</i> is a Gram-positive opportunistic pathogen commonly associated with hospital-acquired and chronic wound infections. Its capacity for biofilm formation and increasing resistance to standard antibiotics, particularly ciprofloxacin (CIP), complicates treatment. The emergence of CIP-resistant <i>E. faecalis</i> (EFR) strains limits existing antibiotic options and requires alternative treatment approaches. Our study evaluated the antibacterial efficacy of a lytic bacteriophage (φR12EFP) and its combination with CIP against <i>E. faecalis</i>. Phage φR12EFP was isolated from environmental samples and characterized. Transmission electron microscopy revealed an icosahedral tailed morphology. Whole-genome sequencing identified a 58.6 kb linear double-stranded DNA genome with high coding density and no lysogeny-associated genes, confirming its classification within the <i>Saphexavirus</i> genus. φR12EFP exhibited host specificity toward <i>E. faecalis</i>. Growth curve analysis showed the emergence of bacterial resistance after 10 h of phage exposure. Adsorption and one-step growth assays demonstrated rapid host attachment, with a burst size of approximately 356 PFU/cell, and optimal antibacterial activity at a multiplicity of infection (MOI) of 0.1. φR12EFP remained stable between 4 and 60 °C and pH 5–9. A CIP-resistant EFR strain was developed under selective pressure to establish a clinically relevant model. Combined treatment with φR12EFP (MOI 0.1) and low-dose CIP (5 µg/mL) exhibited EFR bacterial suppression and restored antibiotic efficacy. The combination reduced established EFR biofilm by 75% and improved embryo survival to 90–100% in an <i>in ovo</i> infection model compared with φR12EFP monotherapy alone. These findings indicate that φR12EFP restores CIP sensitivity in resistant <i>E. faecalis</i> and supports the use of phage–antibiotic regimens against multidrug-resistant enterococci.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035133","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Symbiotic interactions of dark septate endophytic fungi on shallot growth under drought stress","authors":"Celsi Vionada Seprianti,&nbsp;Sri Listiyowati,&nbsp; Surono","doi":"10.1007/s00203-026-05205-w","DOIUrl":"10.1007/s00203-026-05205-w","url":null,"abstract":"<div><p>Drought stress is one of the major factors limiting the growth and productivity of agricultural crops, including shallot (<i>Allium ascalonicum</i> L.). This study aimed to investigate the role of symbiotic associations between dark septate endophytes (DSEs) and shallot plants in improving growth performance, physiological responses, and yield under varying field capacity. A factorial completely randomized design was employed with two factors: DSE inoculation (without DSE, <i>Cladophialophora nyingchiensis</i> S51, and <i>Diaporthe pandanicola</i> TM1) and field capacity levels (100%, 80%, 50%, and 30% of available water). Observed parameters included vegetative growth, physiological responses, root colonization, and bulb yield. The results demonstrated that DSE inoculation significantly enhanced shallot plants’ tolerance to drought stress. <i>Cladophialophora nyingchiensis</i> S51 exhibited superior performance in promoting vegetative growth, increasing plant height by 38%, root length by 122%, leaf biomass by 27%, and root biomass by 130% under severe drought conditions (30% field capacity). In contrast, <i>Diaporthe pandanicola</i> TM1 was more effective in enhancing root biomass (110%) and bulb formation (31%) under severe drought conditions (30% field capacity). Physiologically, both DSE inoculations increased chlorophyll content, reduced malondialdehyde (MDA) accumulation, and enhanced proline production, indicating improved adaptive responses to water deficit. Furthermore, both DSE inoculation increased bulb number and bulb weight across all field capacity levels. These findings demonstrate that <i>C. nyingchiensis</i> S51 and <i>D. pandanicola</i> TM1 have considerable potential as biological agents to improve drought tolerance and enhance shallot productivity in sustainable agricultural systems.</p></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035349","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hematological and biochemical alterations in rainbow trout Oncorhynchus mykiss during a natural Aeromonas sp. outbreak in high-altitude Ladakh, trans-Himalayas","authors":"Riyaz Ahmad,&nbsp;Imtiaz Ahmed,&nbsp;Firdous A. Khanday","doi":"10.1007/s00203-026-05228-3","DOIUrl":"10.1007/s00203-026-05228-3","url":null,"abstract":"<div><p>An outbreak of bacterial septicemia associated with <i>Aeromonas</i> sp. was investigated in intensive high-altitude aquaculture of rainbow trout, <i>Oncorhynchus mykiss</i>, at the Drass fish farm, Ladakh, during the seasonal transition of May–June 2025. This observational study documents physiological associations rather than experimental causality. A total of 72 fish were sampled: 36 severely diseased and 36 asymptomatic but exposed specimens from adjacent raceways of the same facility. Phenotypic, biochemical, and 16S rRNA gene sequencing of isolate SFB099 identified the agent as <i>Aeromonas</i> sp. with sequence similarity to <i>A. salmonicida</i>; however, definitive species-level confirmation was limited by the reliance on a single molecular marker. Diseased fish exhibited severe hematological disturbances, including pronounced leukocytosis and shifts in the systemic erythrocyte index consistent with an anaemic trend. Serum analysis showed possible stress-related hyperglycemia, hypoalbuminemia, and elevated creatinine, blood urea nitrogen, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and alkaline phosphatase. These alterations suggest heightened physiological stress, altered metabolic pathways, and selective ionoregulatory imbalances: hyponatremia, hypochloremia, and elevated potassium. Conclusions about definitive tissue damage are limited by the lack of histopathological validation. Statistical analyses used Spearman’s rank correlation, the Shapiro–Wilk test, and the Wilcoxon rank-sum test. Multivariate analysis via principal component analysis PCA explained a moderate 44.7% cumulative variance across PC1 and PC2, reflecting noticeable group-wise clustering alongside high individual heterogeneity. Water parameters measured concurrently showed structural variations characteristic of early summer glacial melt. This study provides localized physiological data on salmonids reared under extreme trans-Himalayan culture constraints for spontaneous field-outbreak investigations.</p></div>","PeriodicalId":8279,"journal":{"name":"Archives of Microbiology","volume":"208 12","pages":""},"PeriodicalIF":3.4,"publicationDate":"2026-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149035420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}