Brazilian Journal of Microbiology最新文献

{"title":"Genomic and functional characterization of Bacillus subtilis subsp. subtilis INPA R296 with emulsifying activity in cultivation with residual soybean oil.","authors":"Suziane P Rodrigues, José C I Silva, Nadionara C Menezes, Rosineide C de Souza, Aline O Santos, Igor R S Graça, Rogério E Hanada, Larissa K Barbosa, Hector H F Koolen, Gilvan F Silva, Luiz A Oliveira","doi":"10.1007/s42770-026-02098-1","DOIUrl":"10.1007/s42770-026-02098-1","url":null,"abstract":"<p><p>Biosurfactants are amphiphilic microbial metabolites with potential to reduce surface and interfacial tension and to promote emulsification. This study investigated the biosynthetic potential, emulsifying activity, and metabolomic profile of Bacillus subtilis subsp. subtilis INPA R296 cultivated in media supplemented with residual soybean oil. Phylogenomic analyses supported the taxonomic placement of the strain close to Bacillus subtilis subsp. subtilis 168^T. Genome mining predicted 11 biosynthetic gene clusters (BGCs), including NRPS clusters related to surfactin and fengycin biosynthesis. Synteny analyses indicated conservation of these clusters among phylogenetically related Bacillus strains. Functional assays showed that culture-medium composition influenced cell growth, emulsification indices, and emulsifying activity. UHPLC-HRMS/MS combined with molecular networking enabled the putative annotation of metabolites belonging to several chemical classes, including cyclic lipopeptides, N-acyl amino acids, and oxylipins. The main contribution of this study is the integrated evaluation of genomic biosynthetic potential, emulsifying activity, and putative metabolite annotations in strain INPA R296 cultivated with a low-cost agro-industrial residue. Because no biosurfactant yield, surface/interfacial tension, authentic-standard validation, or structural isolation was performed, the results demonstrate emulsifying potential and the occurrence of putatively annotated amphiphilic metabolites rather than confirmed biosurfactant production. These findings identify INPA R296 as a target for further investigation of amphiphilic metabolites with potential biotechnological applications.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13653007/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149147049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antifungal activity of fresh ginger (Zingiber officinale) essential oil from ginger production waste against banana anthracnose caused by Colletotrichum musae: in vitro and in vivo evaluation.","authors":"Maria Alice Brandão Silva, Aldino Neto Venâncio, Isabella da Costa Teixeira, Ana Paula Candido Gabriel Berilli, Sávio da Silva Berilli, Luciana Alves Parreira, Mario Ferreira Conceição Santos, Antônio Fernando de Souza, Luciano Menini","doi":"10.1007/s42770-026-02108-2","DOIUrl":"10.1007/s42770-026-02108-2","url":null,"abstract":"<p><p>Banana anthracnose, caused by Colletotrichum musae, represents an important phytosanitary constraint, traditionally managed with synthetic fungicides, whose intensive use has contributed to environmental impacts and the selection of resistant isolates. In this context, essential oils have emerged as sustainable alternatives, especially when obtained from ginger production waste. This study aimed to characterize the chemical composition and evaluate the in vitro and in vivo antifungal activities of fresh ginger essential oil (Zingiber officinale) (FGEO) extracted from ginger production waste against C. musae. The oil was obtained by hydrodistillation and analyzed by GC-FID and GC-MS. In vitro assays were conducted at concentrations ranging from 0.039 to 0.938 µL mL⁻¹, while in vivo tests used concentrations from 0.201 to 3.212 µL mL⁻¹, including appropriate controls. Chemical analysis revealed predominance of α-zingiberene (31.73%), α-farnesene (14.85%), geranial (13.15%), and sesquiphellandrene (11.04%), with a mean extraction yield of 0.21% (w/w). The FGEO exhibited significant antifungal activity, inhibiting mycelial growth and reducing disease severity. The in vivo IC₅₀ and IC₉₀ values were 0.535 and 2.797 µL mL⁻¹, respectively, demonstrating high efficacy at low concentrations. These results support the potential of FGEO, particularly when obtained from ginger production waste, as a low-concentration, sustainable alternative for postharvest management of banana anthracnose.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13650211/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149134953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unravelling mass mortality in transported rohu (Labeo rohita) fingerlings: evidence of Flavobacterium columnare from Western India.","authors":"Pooja Manoj Vinde, Supradhnya Namdeo Meshram, Saurav Kumar, Anisha Valsalam, Kundan Kumar, Krutika Desai, Megha Kadam Bedekar","doi":"10.1007/s42770-026-02104-6","DOIUrl":"10.1007/s42770-026-02104-6","url":null,"abstract":"<p><p>Columnaris disease caused by Flavobacterium columnare in freshwater farmed fishes is a severe problem, leading to considerable mortality. The present study investigated the mass mortality happened in Labeo rohita fingerlings within 48 h post-transportation from an organized fish farm in Maharashtra, India, to the laboratory. The moribund fish showed clinical signs analogous to columnaris and the bacterial isolation showed pale yellow rhizoid edged tightly adhered colonies which are found as slender rod-shaped bacteria by TEM. Molecular analysis of the isolate using 16S rRNA nucleotide homology and phylogenetic analysis showed ≥ 98% similarity with F. columnare BRTAGILLFC01 strain. RFLP analysis demonstrated that the isolate belongs to genomovar II. To test whether hypoxia during transportation influenced the pathogenicity of bacteria, the hypoxic stress (dissolved oxygen, DO: 2.50 ± 0.50 mg/L) was simulated in an experimental setting with F. columnare challenge to L. rohita, which was compared to the optimum setting of normoxic condition with DO: 6.00 ± 0.50 mg/L. Significant infection enhancement was observed in hypoxic condition as evident from 100% accumulated mortality within 48 h post-challenge compared to 80% in the normoxic group with varied LD₅₀ values of 5.30 × 10⁵ CFU/mL, and 1.24 × 10⁶ CFU/mL, respectively. Severe to moderate histopathological alterations were recorded in the affected gill, kidney, and liver tissues such as the loss of secondary gill lamellae, tubular, epithelial and glomerular degeneration and pyknotic nucleus with increased sinusoidal space, in the respective tissues. The study evidenced that the hypoxic condition during transportation may induce F. columnare infection associated mass mortality in L. rohita fingerlings within the short span of post-transportation stress.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13642877/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149104201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How safe from Listeria monocytogenes are frozen ready-to-eat fish products, either cooked or smoked, when stored under refrigeration after purchasing?","authors":"Mayara S Tavares, Patrícia G Paulino, Daniele S Juliano, Roberto Laureano-Melo, Huarrisson A Santos, Rosa H Luchese","doi":"10.1007/s42770-026-02103-7","DOIUrl":"10.1007/s42770-026-02103-7","url":null,"abstract":"<p><p>This research aimed to access the incidence of Listeria sp. and L. monocytogenes in frozen ready-to-eat (RTE) fish products immediately after purchasing, and after refrigerated storage. Out of 72 kani-kama samples, 17 (23,6%) and 16 out of 48 samples (33,3%) of smoked salmon samples, tested positive for Listeria sp. by the traditional culture method, whereas 45,8% and 56.2% were positive by PCR, for kani-kama and smoked salmon samples, respectively. Applying qPCR, 21 samples of kani-kama out of 72 (29.2%) and 23 out of 48 samples of smoked and sliced salmon (47.9%) were positive for L. monocytogenes. Quantification was performed by culture to account only for viable cells, and confirmation was carried out via PCR and qPCR for Listeria sp. and L. monocytogenes, respectively. The average counts of L. monocytogenes did not exceed 2 Log CFU/g, both in kani-kama or smoked salmon. However, 15.3% of individual kani-kama samples and 14,6% of smoked salmon samples showed counts of up to 3.2 Log CFU/g, some even immediately after purchasing. Higher number of positive samples was observed during refrigerated storage compared to the number of samples analysed immediately after purchasing, indicating that refrigeration for a long time can pose an additional health threat. Unlike kani-kama, which is a heat-processed product, a higher background microbiota count was detected in smoked salmon. However, this background microbiota apparently did not influence the growth of Listeria spp.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638846/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149104198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Qualitative assessment of virulence and resistance gene transcripts in Staphylococcus aureus isolated from buffalo milk and dairy products.","authors":"Mustafa Bilgin","doi":"10.1007/s42770-026-02100-w","DOIUrl":"10.1007/s42770-026-02100-w","url":null,"abstract":"<p><p>Staphylococcus aureus is a major foodborne pathogen capable of producing enterotoxins and exhibiting antimicrobial resistance, posing a significant risk to public health through contaminated dairy products. This study investigated the occurrence of S. aureus isolates recovered from buffalo milk and dairy products, along with the potential presence of selected virulence and resistance gene transcripts. A total of 100 samples, including raw buffalo milk, cream, and cheese, were analyzed using classical microbiological methods. Isolates were characterized phenotypically, and methicillin resistance was assessed by disk diffusion. The potential presence of gene transcripts of nuc, mecA, pvl, and classical enterotoxin genes (sea, seb, sec, and sed) were evaluated using RT-qPCR. Despite DNase I treatment, clear gene-specific melting peaks, and early cycle thresholds, results were interpreted cautiously to account for potential genomic DNA amplification due to the lack of no-reverse-transcriptase (NRT) controls. S. aureus was recovered from 12% of the samples, with the highest recovery observed in cheese. A total of 21 S. aureus isolates were obtained and further characterized. All isolates exhibited amplification corresponding to pvl and at least one enterotoxin gene, with sec-related signals being the most frequently detected. Phenotypic testing classified 61.9% of the isolates as methicillin-resistant based on cefoxitin disk diffusion, while mecA gene amplification were detected in 71.4% of the isolates. These findings suggest that S. aureus isolates recovered from buffalo dairy products, particularly traditionally produced cheese, may carry virulence- and resistance-associated genetic features of potential public health relevance. The combined phenotypic and screening approach used in this study provides additional insight into potential food safety concerns associated with buffalo-derived dairy products.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638842/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149104188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Computational introspection of impact of mutation A90V and A90E in DNA gyrase a of Mycobacterium tuberculosis in developing resistance against Delafloxacin.","authors":"Sumit Kumar Rai, Dev Bukhsh Singh, Pramod Kumar Yadav, Sapna Pandey, Satendra Singh","doi":"10.1007/s42770-026-02077-6","DOIUrl":"10.1007/s42770-026-02077-6","url":null,"abstract":"<p><p>Quinolone group antibiotics have proven to be an effective drug against Mycobacterium tuberculosis. However, point mutation in DNA gyrase, one of the primary targets for quinolone antibiotics, has led to conformational alterations in the binding sites, leading to a change in drug pharmacodynamics. This has contributed to the development of drug-resistant strains such as multidrug-resistant strains (MDR) and an extreme drug-resistant strains (XDR). In this study, our objective was to find the impact of mutation A90V and A90E on DNA Gyrase A of Mycobacterium tuberculosis. Ten quinolone antibiotics were docked with DNA gyrase (3ILW_wild) to find the antibiotic with the highest binding affinity and favorable interactions. Delafloxacin forms a stable energy complex with - 8.6 kcal/mol, among all docked quinolone antibiotics. Two-point mutation A90E and A90V at position 90 were introduced in the 3ILW_wild model, and generated mutant models 3ILW_A90E and 3ILW_A90V and were docked again with the Delafloxacin to observe the changes in interaction due to mutation. A comparative molecular dynamics simulation study for the complex of Delafloxacin with 3ILW_wild, 3ILW_A90E, and 3ILW_A90V were conducted for 100ns to observe the conformational changes, fluctuations, compactness, and binding pattern. Structural dynamics due to the mutations A90V and A90E, and its effect on the shape and geometry of the Delafloxacin binding site of DNA gyrase before and after the mutation, can help in understanding the mechanism behind resistance and also in developing novel, swift-acting antibiotics with better efficacy.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13638977/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149104130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular types, clinical profile, and exploratory virulence-associated phenotypes of clinical Cryptococcus isolates from Amazonas, Brazil.","authors":"Robert Langlady Lira Rosas Filho, Izabela de Mesquita Bárcia Moreira, Nayara de Fátima Lazameth-Diniz, Flávia Fernandes Souza, João Flávio Dias do Val Bisneto, Naira Sulany Oliveira de Sousa, Juan Diego Ribeiro de Almeida, Érica Simplício de Souza, Kátia Santana Cruz, Carla Silvana da Silva Santos, Hagen Frickmann, João Vicente Braga de Souza","doi":"10.1007/s42770-026-02094-5","DOIUrl":"https://doi.org/10.1007/s42770-026-02094-5","url":null,"abstract":"<p><strong>Background: </strong>Cryptococcosis remains a severe systemic mycosis, especially among people living with HIV/AIDS, and culture-based molecular data from Amazonas remain limited.</p><p><strong>Objectives: </strong>The aim was to identify which Cryptococcus molecular types circulated among clinical isolates from Amazonas between 2020 and 2024; what were the main clinical characteristics and outcomes of patients infected with Cryptococcus neoformans molecular type VNI and Cryptococcus gattii molecular type VGII; and whether these molecular types differed in selected susceptibility-related and virulence-associated phenotypes.</p><p><strong>Methods: </strong>We analyzed 70 culture-confirmed clinical isolates from patients treated at the Dr. Heitor Vieira Dourado Tropical Medicine Foundation, Manaus, Brazil. Molecular types were assigned by URA5 PCR-RFLP using reference strains. Demographic and clinical variables were retrieved from medical records. A stratified 30-isolate subset comprising 24 VNI and 6 VGII isolates was evaluated for phospholipase activity and melanization. Fluconazole MICs were analyzed for the complete 70-isolate dataset and were determined by broth microdilution according to CLSI M27-A4.</p><p><strong>Results: </strong>VNI predominated (64/70; 91.4%), whereas VGII accounted for 6/70 isolates (8.6%). The series was predominantly composed of men, young adults, and HIV-positive patients. HIV infection was more frequent among VNI cases, whereas VGII included proportionally more HIV-negative patients. In-hospital death occurred in 17/70 patients (24.3%). Fluconazole MICs, phospholipase activity, and melanization were broadly comparable between VNI and VGII, although the small VGII subgroup precluded robust genotype-associated inference.</p><p><strong>Conclusion: </strong>VNI was the dominant molecular type in this severe reference-center cryptococcosis series from Amazonas. Phenotypic findings should be interpreted as exploratory and hypothesis-generating.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13627509/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149104165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bacilli the most important biocontrol agent in Brazilian agriculture: from mechanisms of action to market adoption.","authors":"Wagner Bettiol, Roberto Lanna-Filho, Cristiano Limberger","doi":"10.1007/s42770-026-02096-3","DOIUrl":"10.1007/s42770-026-02096-3","url":null,"abstract":"<p><p>Bacilli have become one of the most commercially significant groups of microorganisms used in agricultural biocontrol products in Brazil. Their ability to form endospores and produce a wide range of metabolites allows them to control plant diseases, promote plant growth, and alleviate stress, supporting their extensive adoption in crop protection systems. This study analyzes the Brazilian market for Bacillus-based products used in plant disease management and summarizes their mechanisms of action. Data on commercial registrations, active strains, product formulations, and target diseases were compiled from Brazilian national regulatory databases. Market indicators, such as potential area treated (PAT) and turnover, were estimated using structured agricultural surveys conducted across Brazil during the 2019/2020 and 2024/2025 crop seasons, the latter encompassing more than 16,000 interviews with farmers and agricultural managers. By December/2025, 297 Bacillus-based products containing 126 strains were commercialized in Brazil, with Bacillus amyloliquefaciens, B. subtilis, B. velezensis, and B. pumilus being the most prominent species. These products are applied via seed treatment, soil drenching, furrow, and foliar spraying to manage fungal, bacterial, and nematode diseases. During the analyzed period, PAT increased from 7.5 to 37.2 million hectares (391% growth) and turnover increased from US$114.31 to US$403.17 million (252% growth). Currently, Bacillus-based products accounted for approximately 48% of the Brazilian biological control market, highlighting the prevalence of this genus in the sector. Overall, these results demonstrate how advances in microbial biotechnology, regulatory development, and farmer adoption have positioned Bacillus spp. as key components of the rapidly expanding biocontrol industry.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13620009/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149073430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Biocontrol of Staphylococcus aureus in dairy products using lytic bacteriophage UHP46: efficacy in milk, cheese, and yogurt.","authors":"Sara Najeeb, Imran Khan, Javed Muhammad, Muhammad Jahangir, Anza Abbas, Aman Ullah, Amjad Khan, Sumaira Miskeen","doi":"10.1007/s42770-026-02081-w","DOIUrl":"10.1007/s42770-026-02081-w","url":null,"abstract":"<p><p>Staphylococcus aureus is a major public health concern in the dairy industry. It is a well-recognized pathogen responsible for bovine mastitis and raw milk contamination; certain strains produce heat-stable enterotoxin capable of causing staphylococcal food poisoning in humans. The emergence of multiple drug-resistant strains of S. aureus has rendered ineffective the use of antibiotics for control purposes. This study determined the antibacterial activity of lytic bacteriophage UHP46 against a single, previously characterized multidrug-resistant mastitis isolate, S. aureus S46, in three dairy matrices - milk, cheese and yogurt - under storage conditions representing refrigerated storage (4 °C), ambient conditions (25 °C) and a 37 °C mechanistic reference condition. UHP46 significantly reduced S. aureus S46 counts in milk, achieving reductions of 3.2 and 3.7 log₁₀ CFU/mL after 4 and 24 h at 4 °C, 2.1 and 3.1 log₁₀ CFU/mL after 4 and 24 h at 25 °C, and 1.8 log₁₀ CFU/mL after 3 h at 37 °C. The reduction at 37 °C was accompanied by an increase in phage titer from 7.2 to 8.8 log₁₀ PFU/mL. Application of UHP46 to cheese resulted in an immediate reduction of 0.6 log₁₀ CFU/g after 5 min of treatment at room temperature. The maximum reduction observed was 2.0 log₁₀ CFU/g at 24 h, with a sustained reduction of 1.9 log₁₀ CFU/g maintained through 96 h of refrigerated storage at 4 °C. In yogurt, net reductions on day 6 were 2.8, 2.7, and 1.6 log₁₀ CFU/g at 37 °C, 25 °C, and 4 °C, respectively. The findings indicate that UHP46 exhibits significant antibacterial activity against S. aureus S46 within the tested dairy matrices and under the evaluated storage conditions. However, as all challenge experiments utilized a single host strain, its efficacy against a broader panel of S. aureus, including methicillin-resistant S. aureus (MRSA), remains to be determined.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13612768/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149036441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Organic acid-associated antimicrobial and antibiofilm activity of Lactobacillus rhamnosus ATCC 7469 against Acinetobacter baumannii and Staphylococcus aureus.","authors":"Mariana Silveira Mello Silva, Priscila Cristina Bartolomeu Halicki, Carlos James Scaini, Jean Lucas de Oliveira Arias, Daniela Fernandes Ramos, Luciana Farias da Costa Avila","doi":"10.1007/s42770-026-02095-4","DOIUrl":"10.1007/s42770-026-02095-4","url":null,"abstract":"<p><p>Considering the relevance of biofilms in bacterial resistance and the need for innovative therapies against pathogenic microorganisms, alternative strategies using probiotics as antimicrobial agents have emerged. This study aimed to evaluate the antimicrobial and antibiofilm activities of the cell-free supernatant (CFS) of Lactobacillus rhamnosus ATCC 7469 against biofilm-forming strains of Acinetobacter baumannii and Staphylococcus aureus. The activity of CFS was evaluated against A. baumannii ATCC 19606, A. baumannii 301, S. aureus ATCC 12598, and S. aureus ATCC 29213. Antimicrobial activity against planktonic cells, inhibition of biofilm formation, and destruction of mature biofilms were assessed at different CFS dilutions. The corresponding concentrations of lactic and acetic acids were determined by high-performance liquid chromatography (HPLC). CFS showed high antimicrobial activity, with growth inhibition ranging from 88.26% to 100% at the two highest concentrations tested (197.8/108.7 and 107.0/54.5 mM lactic/acetic acid). At 57.8/28.3 mM, growth inhibition ranged from 60.05% to 81.65%, whereas at 27.2/13.5 mM it ranged from 21.12% to 41.03%. CFS also strongly inhibited biofilm formation, with inhibition rates ranging from 66.17% to 100%, whereas destruction of mature biofilms ranged from 24.75% to 88.11%. HPLC analysis demonstrated the presence of lactic and acetic acids in the CFS, with lactic acid being the predominant organic acid detected. Neutralization of the CFS to pH 7.0 markedly reduced its antimicrobial and antibiofilm activities, supporting an important contribution of acidity and acid-associated components to the observed effects. Overall, L. rhamnosus ATCC 7469 CFS exhibited substantial antimicrobial and antibiofilm activity against A. baumannii and S. aureus, supporting further investigation of Lactobacillus-derived CFS as a potential local antimicrobial strategy.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13612767/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149036436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}