Journal of Applied Microbiology最新文献

{"title":"Surface-displayed multivalent PRRSV tandem antigen on Bacillus subtilis spores induces mucosal immune responses in mice.","authors":"Yang Yang, Jianzhen Li, Pengfei Fang, Bin Chen, Yicen Tang, Xixi Dai, Lei Fei, Yunfei Xiao, Yanpeng Dong, Chunfeng Shi, Xueqin Ni, Bo Jing, Kangcheng Pan","doi":"10.1093/jambio/lxag114","DOIUrl":"https://doi.org/10.1093/jambio/lxag114","url":null,"abstract":"<p><strong>Aims: </strong>Porcine reproductive and respiratory syndrome virus (PRRSV) remains a major threat to swine production, while safe and practical mucosal immunization strategies with broad reactivity are still limited. This study aimed to develop a spore surface-display mucosal immunomodulatory platform by presenting a multiepitope PRRSV antigen on Bacillus subtilis spores and to assess its ability to stimulate mucosal and systemic immune responses.</p><p><strong>Methods and results: </strong>An applied spore surface-display platform was constructed by engineering Bacillus subtilis 168 spores to present a tandem fusion antigen (ER) comprising conserved linear B- and T-cell epitopes derived from PRRSV ORF1b, GP5, M, and N proteins. Recombinant spores were administered orally to BALB/c mice as a proof-of-concept model, and mucosal and systemic immunogenicity was evaluated in comparison with control spores and a commercial inactivated vaccine. B. subtilis BE significantly increased ER-specific intestinal secretory IgA and serum IgG, and PRRSV (R98)-specific neutralising activity was detectable in the ER group. BE administration also promoted a Th1-skewed mucosal cytokine profile (increased IFN-α, TNF-α, and IFN-γ with reduced IL-6) and increased the proportion of CD8⁺ T cells in mesenteric lymph nodes.</p><p><strong>Conclusions: </strong>Surface display of a conserved multiepitope PRRSV antigen on B. subtilis spores stimulated coordinated mucosal, humoral, and cellular immune responses in mice. These findings support further exploration of spore-based microbial delivery systems as a potential mucosal immunisation adjuvant and immunomodulatory approach for PRRSV; however, the use of BALB/c mice represents a non-natural host model, and protective efficacy remains to be validated in target animals and challenge studies.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147863931","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":"Divergent Assembly Mechanisms and Functional Dominance of Ammonia Oxidizers in Lancang River Cascade Reservoir Sediments.","authors":"Bo Yuan, Jiachao Li, Yuan Li, Mengjing Guo, Miaojie Li, Shuguang Xie","doi":"10.1093/jambio/lxag115","DOIUrl":"https://doi.org/10.1093/jambio/lxag115","url":null,"abstract":"<p><strong>Aims: </strong>Cascade hydropower development profoundly alters riverine ecosystems, yet how it influences ammonia-oxidizing microorganisms in reservoir sediments remains unclear. This study aimed to elucidate the relative functional contributions, community assembly mechanisms, and environmental drivers of ammonia-oxidizing archaea (AOA) versus bacteria (AOB) across seven cascade reservoirs in the Lancang River.</p><p><strong>Methods and results: </strong>We collected surface sediments seasonally and employed quantitative PCR, high-throughput sequencing, and multivariate analyses. AOA amoA gene abundance consistently exceeded that of AOB, and potential nitrification rate correlated significantly only with AOA abundance, indicating AOA functional dominance. AOA communities exhibited higher diversity, stronger spatial structuring, and deterministic assembly governed by environmental selection, while AOB assembly was more stochastic. Dominant AOA (Nitrososphaera) and AOB (Nitrosospira) shifted spatially, with marine-related Nitrosopumilus appearing only in mid- and downstream reservoirs. Water depth and hydraulic retention time primarily influenced AOB, whereas AOA were regulated by C/N ratio, pH, and reservoir age.</p><p><strong>Conclusions: </strong>This study demonstrates that AOA, rather than AOB, dominate ammonia oxidation among canonical ammonia oxidizers in cascade reservoir sediments and that damming-induced environmental gradients drive divergent assembly mechanisms between these functional groups. These findings challenge conventional nitrification paradigms in river systems and provide a predictive framework for managing nitrogen cycling in the rapidly expanding global network of dammed rivers.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147838259","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":"Homovanillic acid inhibits Candida albicans-Staphylococcus aureus polymicrobial biofilm: in vitro and in vivo evaluation.","authors":"Anmol Kulshrestha, Pratima Gupta, Sumit Sahu, Priya Komre, Sanjay Kumar Gupta, Avani Tiwari","doi":"10.1093/jambio/lxag111","DOIUrl":"https://doi.org/10.1093/jambio/lxag111","url":null,"abstract":"<p><strong>Aims: </strong>Candida albicans and Staphylococcus aureus polymicrobial biofilms cause chronic wound infections and tolerate standard antimicrobials poorly. Their endurance is driven by fungal hyphal morphogenesis, interkingdom co-aggregation, and virulence proteins, including SAP5, which create a strong polymicrobial biofilm. Homovanillic acid, a plant-derived phenolic molecule, was tested for its antibiofilm effects on hyphal growth, bacterial-fungal interactions, and SAP5-associated pathogenicity.</p><p><strong>Methods and results: </strong>Integrated in vitro, real-time dynamic, and in vivo methods were used to assess antibiofilm activity. Microtiter plate experiments evaluated the minimum biofilm inhibitory concentration (MBIC), whereas a real-time Biofilm Infection Simulator System examined biofilm formation under flow circumstances. SAP5 proteinase activity was measured spectrophotometrically, and microbiological and histological investigations confirmed in vivo efficacy in a catheter-associated rat wound model. HVA significantly inhibited polymicrobial biofilm initiation at sub-inhibitory concentrations, with an MBIC of 128 µg mL-1 corresponding to an 82.18% reduction in biofilm formation. Real-time analysis confirmed substantial suppression of biofilm development. Inhibition of C. albicans hyphal morphogenesis impaired S. aureus adhesion and destabilized biofilm architecture, while SAP5 activity was reduced by 53.37%. In vivo treatment promoted effective wound healing, marked by reduced inflammation, near-complete epithelial regeneration, and organized collagen deposition by day 14.</p><p><strong>Conclusions: </strong>HVA demonstrates potent multitarget antibiofilm activity and represents a promising plant-derived therapeutic candidate for managing polymicrobial biofilm-associated wound infections.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147838316","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":"Recovering viable bacteriophages from human milk: implications for sample storage and processing.","authors":"Ranran Li, Julianne Megaw, Natalie S Shenker, Simon J S Cameron","doi":"10.1093/jambio/lxag109","DOIUrl":"https://doi.org/10.1093/jambio/lxag109","url":null,"abstract":"<p><strong>Aims: </strong>Molecular methods have shown bacteriophage diversity in human milk, but this does not reflect viability, particularly within donor human milk which has been subjected to multiple freeze-thaw cycles and heat treatment. Our aim was to isolate bacteriophages from frozen human milk and explore the effects of sterilization and storage on bacteriophage survival.</p><p><strong>Methods and results: </strong>20 frozen human milk samples were chosen for bacteriophages isolation. Analysis showed that these samples stored for 12 months at -20°C did not contain viable bacteriophages. We artificially inoculated 10 human milk and 10 water control samples with Escherichia coli bacteriophage T4 and subjected them to various treatments. We found that ultraviolet-C irradiation significantly inactivated E. coli phage T4 (p < 0.001), with greater inactivation observed in skimmed milk (p < 0.001) than whole milk. In contrast, Holder and High Temperature Short Time pasteurisation had no significant effect (p > 0.05). The E. coli bacteriophage T4 was better preserved at 4°C than at room temperature over 48 hours. Over 90 days of storage, bacteriophage viability was higher at -80°C (31.6%) than at -20°C (9.4%).</p><p><strong>Conclusions: </strong>Future work on bacteriophage isolation from human milk should consider the use of fresh samples whenever possible. Where samples are stored prior to analysis this should be at a refrigerated temperature for up to 48 hours, and if samples are to be stored longer term, then -80°C is suitable for up to three months and preferable to -20°C, with storage only up to seven days.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147838332","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":"Volatile Solids Outperform Pepper Mild Mottle Virus (PMMoV) as a Normalizing Parameter in Wastewater-Based Epidemiology: A 3-Year Multi-Site Comparative Study.","authors":"Hassan Waseem, Lena Carolin Bitter, Timothy Garant, Gabriela Jimenez Pabon, Richard Kibbee, Banu Örmeci","doi":"10.1093/jambio/lxag110","DOIUrl":"https://doi.org/10.1093/jambio/lxag110","url":null,"abstract":"<p><strong>Aims: </strong>Wastewater-based epidemiology (WBE) requires reliable normalization to account for dilution and population variability across sampling locations. Although Pepper Mild Mottle Virus (PMMoV) is widely used as a viral fecal marker for normalization, its effectiveness varies considerably across sewersheds. This study aims to evaluate volatile solids (VS), a routine physicochemical wastewater parameter, as an alternative normalization marker over a multi-year, multi-site investigation.</p><p><strong>Methods and results: </strong>We analyzed 1,611 wastewater samples from five distinct locations in Eastern Ontario, including four wastewater treatment plants and one university campus, over three years. PMMoV and VS concentrations were measured and compared to assess their temporal stability and correlation with population size. VS exhibited markedly lower variability (monthly robust coefficients of variance 0.11-0.18) compared to PMMoV (0.30-0.52), whose concentrations fluctuated up to 100-fold within single sites and declined year-wise. VS concentrations remained stable with less than 6-fold variation. Linear regression showed that VS was strongly associated with population size (R² = 0.721, p = 0.044), whereas PMMoV showed no significant correlation (R² = 0.054, p = 0.706). Negative correlations between PMMoV and wastewater pH (p < 0.001) across multiple sites suggest that pH-dependent degradation affects PMMoV stability.</p><p><strong>Conclusions: </strong>VS provided a more consistent normalization parameter than PMMoV in this multi-year, multi-site dataset, suggesting that routinely measured VS can serve as a practical normalization option for WBE in similar sewersheds. It requires simple, cost-effective measurement techniques and reflects fecal content independently of dietary fluctuations affecting molecular markers.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147838337","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":"Characteristics of carbon-fixing microbial communities and pathways across different aquatic systems in the Tianjin Binhai region.","authors":"Dongping Zhao, Cuixia Zhang, Mengdi Li, Haiming Li, Sihui Su, Xiaodong Zhang","doi":"10.1093/jambio/lxag112","DOIUrl":"https://doi.org/10.1093/jambio/lxag112","url":null,"abstract":"<p><strong>Aims: </strong>Microbial carbon fixation is central to carbon cycling and carbon sink functioning in coastal aquatic ecosystems. Although carbon fixation pathways have been increasingly investigated across diverse aquatic environments, comparative evidence remains limited for hydrologically connected yet hydrochemically contrasting coastal groundwater and surface water systems. This study aimed to compare carbon-fixation-associated microbial communities and major carbon fixation pathways across groundwater, river water and reservoir water in the Tianjin coastal region.</p><p><strong>Methods and results: </strong>We integrated metagenomic sequencing with hydrochemical analyses to characterise carbon-fixation-associated microbial communities and six representative carbon fixation pathways. Surface waters were dominated by bacteria and showed relatively stable community composition, whereas groundwater communities comprised both bacteria and archaea and displayed pronounced spatial heterogeneity. The Calvin-Benson-Bassham cycle was prevalent across all water types, and the reductive tricarboxylic acid (rTCA) cycle was also widely distributed. Groundwater showed higher contributions of the Wood-Ljungdahl pathway, the archaeal 3-hydroxypropionate/4-hydroxybutyrate and dicarboxylate/4-hydroxybutyrate cycles, together with the rTCA cycle, indicating coexisting carbon fixation strategies. Pathway abundance and module completeness further suggested differences in pathway integrity among water types. Total dissolved solids, HCO3⁻, CO32⁻ and dissolved organic carbon were key correlates of carbon fixation gene distribution.</p><p><strong>Conclusions: </strong>Carbon-fixation-associated microbial communities, pathway distributions, and pathway integrity differed markedly between coastal groundwater and surface waters. Groundwater exhibited enhanced non-CBB cycle potentials and more diversified carbon fixation strategies, highlighting the importance of groundwater processes in evaluating carbon sequestration potential and carbon cycling in hydrochemically heterogeneous coastal aquatic systems.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147838289","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":"Gold, platinum, and palladium ions demonstrate strong antimicrobial action against hospital pathogens with reduced effect in the presence of bovine plasma soil.","authors":"Misha Vaidya, Iffat Shahzad, Andrew J McBain, Hayley Andrews, Kathryn A Whitehead","doi":"10.1093/jambio/lxag080","DOIUrl":"10.1093/jambio/lxag080","url":null,"abstract":"<p><strong>Aims: </strong>The antimicrobial efficacy of five metal ions (silver, copper, platinum, gold, and palladium) was assessed against Klebsiella pneumoniae, Acinetobacter baumannii, and Enterococcus faecium in the presence and absence of a bovine plasma soil. Changes in the elemental structure of the bacteria were identified.</p><p><strong>Methods: </strong>Planktonic and biofilm inhibition assays were carried out in the absence and presence of a 10% bovine plasma soil. Elemental changes to the bacteria were determined using energy-dispersive X-ray spectroscopy (EDX).</p><p><strong>Results: </strong>The reduction in planktonic bacteria without soil was 8-log at 0 h for gold and palladium ions, and with soil, platinum demonstrated a 7-log reduction at 4 h against K. pneumoniae and A. baumannii. For E. faecium with and without soil, a 4-log reduction at 24 h with silver ions was demonstrated. Reduction of biofilm without soil was 88.8% against K. pneumoniae (platinum) 91.2% (gold) against A. baumannii, and 82.3%-82.9% (platinum/palladium/gold) against E. faecium. With soil, biofilm reduction for K. pneumoniae or A. baumannii with gold ions was 82.3%, and with gold ions against E. faecium 25.5%. Elemental changes following metal ion treatment could be indicative of cellular damage but did not always correlate with the antimicrobial activity. In the presence of the soil, a decrease in the antimicrobial efficacies was demonstrated, and fewer elemental changes were detected.</p><p><strong>Conclusions: </strong>Platinum, palladium, and gold ions were the most effective antimicrobials. Across all three tested genera, soils reduced the antimicrobial activity.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147772238","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":"Enhanced antibiofilm activity of environmental bacteriophages in combination with antibiotics against relevant Gram-negative pathogens.","authors":"Alejandra Flores-Ibarra, Susana de la Torre-Zavala, Humberto Antonio Salazar-Sesatty, José Alberto Valadez-Lira, Lorena Leticia Vázquez-Ávila, Daniel Salas-Treviño, Paola Bocanegra-Ibarias, Adrián Camacho-Ortiz, José Álvarez-Contreras, Samantha Flores-Treviño","doi":"10.1093/jambio/lxag101","DOIUrl":"10.1093/jambio/lxag101","url":null,"abstract":"<p><strong>Aims: </strong>The aim of this study was to assess the antimicrobial and antibiofilm activity of wastewater bacteriophages in combination with conventional drugs against relevant Gram-negative pathogens in vitro.</p><p><strong>Methods and results: </strong>Host bacterial strains (Stenotrophomonas spp., Burkholderia spp., and Achromobacter spp.) were obtained from a third-level hospital in Mexico. The antimicrobial susceptibility profile and biofilm production of these strains were assessed by broth microdilution and crystal violet staining. Environmental bacteriophages isolated from wastewater were tested against the host strains using the spot test. Phage purification and titration were performed using the double-layer LB agar method. The antibiofilm activity in combination with conventional antibiotics were assessed. Lytic activity of the environmental bacteriophages was observed against Stenotrophomonas maltophilia (Sma2), Achromobacter denitrificans (Ade2), and A. xylosoxidans (Axy4). The latent period of the bacteriophages was 20-30 min, and the estimated burst size was H 12-300 phages per infected cell. The bacteriophage Ade2 showed strong binding affinity, efficient attachment, and continuous lytic activity. The activity of isolated phages against the bacterial strains in their biofilm state showed enhanced antibiofilm activity with meropenem against A. denitrificans, and A. xylosoxidans with trimethoprim-sulfamethoxazole against A. xylosoxidans, and S. maltophilia.</p><p><strong>Conclusions: </strong>Wastewater environmental bacteriophages showed enhanced activity in vitro against biofilm-associated infections caused by Achromobacter and Stenotrophomonas species in combination with conventional drugs, such as meropenem and trimethoprim-sulfamethoxazole, which otherwise would show resistance.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147729000","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":"Trichoderma afroharzianum behaves differently in interaction with pea plants under varying iron availability.","authors":"Ahmad H Kabir, Asha Thapa, Bishrant Pant, Maruf Khan, Shifat Ara Saiful, Shyamal K Talukder","doi":"10.1093/jambio/lxag107","DOIUrl":"10.1093/jambio/lxag107","url":null,"abstract":"<p><strong>Aims: </strong>Trichoderma afroharzianum T22 is widely recognized for enhancing plant stress resilience, yet its effects in pea plants may vary depending on iron (Fe) availability.</p><p><strong>Methods and results: </strong>We assessed the impact of T22 on pea grown under differential Fe status through integrated physiological and omics analyses. We found that the benefits of T22 are highly context dependent, demonstrating improvements in photosynthesis and Fe/N accumulation under Fe deficiency but minimal effects under sufficiency. RNA-seq identified 262 DEGs under Fe deficiency and 555 DEGs under Fe sufficiency following T22 inoculation, with the latter primarily associated with basal metabolic functions, indicating potential colonization costs rather than adaptive responses. Particularly, T22 inoculation upregulated symbiosis-related genes (Nodule-specific GRPs, Major facilitator, sugar transporter-like), Fe transporters (NRAMPs, HMAs), and redox-associated genes (Glutathione S-transferase, Glutathione peroxidase) in the roots under Fe shortage, reflecting a coordinated response to enhance nutrient acquisition and stress tolerance. Microbiome profiling revealed that T22 reshaped the root community by enriching several bacterial taxa such as Comamonadaceae, Pseudomonadaceae, and Mitsuaria under Fe deficiency. These enriched bacterial taxa may act as potential \"helpers\" to T22 by providing complementary beneficial effects under Fe deficiency. In contrast, under Fe-sufficient conditions, microbial restructuring was largely limited to the enrichment of Rhizobiaceae and Pararhizobium. Fungal taxa showed minimal changes, except for the enrichment of Paecilomyces in response to T22 under Fe-deficient conditions.</p><p><strong>Conclusions: </strong>These findings indicate that T22 acts in a context-dependent manner, with bacterial enrichment varying with Fe availability, while fungal taxa were largely unaffected.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147772169","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":"Occurrence and persistence of carbapenem-resistant Klebsiella pneumoniae complex in urban rivers of the São Paulo metropolitan region.","authors":"Pedro Smith Pereira Ferraro, Nazareno Scaccia, Milena Dropa, Solange Martone-Rocha, Camila Fonseca Rizek, Gabrielly Lacerda de Aragão, Ana Luiza da Circuncizão Marques, Dalton Walan Gonçalves Santos, Beatriz Meiwald, Maria Júlia Jordão de Souza Aguiar, Érika Regina Manuli, Fátima L S Nunes, Maria Clara Padoveze, Alison Holmes, Anna S Levin, Sílvia Figueiredo Costa, Maria Tereza Pepe Razzolini","doi":"10.1093/jambio/lxag096","DOIUrl":"10.1093/jambio/lxag096","url":null,"abstract":"<p><strong>Aims: </strong>Urban aquatic environments are increasingly recognized as important components in the persistence and dissemination of antimicrobial-resistant bacteria. This study investigated the occurrence, antimicrobial resistance profiles, and genomic characteristics of carbapenem-resistant Klebsiella pneumoniae complex isolated from urban rivers in São Caetano do Sul, part of the São Paulo Metropolitan Region, Brazil.</p><p><strong>Methods and results: </strong>Between October 2023 and October 2024, 39 surface water samples were collected from two urban streams and processed using selective culture, MALDI-TOF identification, antimicrobial susceptibility testing, and whole-genome sequencing. Among 144 K. pneumoniae complex isolates recovered, 43 (29.9%) were resistant to meropenem. All meropenem-resistant K. pneumoniae isolates carried the blaKPC gene, while one Klebsiella quasipneumoniae isolate harbored blaNDM. Multilocus sequence typing revealed high genetic diversity, with predominance of global disseminated high-risk lineages, including ST11 and ST258. The repeated detection of identical sequence types across different sampling sites and time points suggests environmental persistence within the urban river network.</p><p><strong>Conclusion: </strong>These findings demonstrate that urban surface waters act as reservoirs for clinically relevant carbapenem-resistant Klebsiella lineages, highlighting the importance of environmental surveillance as part of applied strategies to monitor antimicrobial resistance in urban settings.</p>","PeriodicalId":15036,"journal":{"name":"Journal of Applied Microbiology","volume":" ","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13137935/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147673607","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}