Brazilian Journal of Microbiology最新文献

{"title":"Analytical characterization, antifungal activity and textile dyeing of blue green pigment produced by Pseudomonas aeruginosa for potential industrial application.","authors":"Aarushi Chaudhary, Upma Dutta, Sneahpreet Kour, Sachin Gupta, Tanika Mahajan, Julie D Bandral","doi":"10.1007/s42770-026-02046-z","DOIUrl":"10.1007/s42770-026-02046-z","url":null,"abstract":"<p><p>Pseudomonas aeruginosa produces the blue-green phenazine pigment known as pyocyanin, which has shown promise in the fields of health, agriculture, environmental protection, and cosmetics. Because of their natural colour, safety, and inexpensive manufacturing costs, microbial pigments are a promising substitute for natural pigments and offer a wide range of possible applications. The present work focused on the extraction of a blue-green pigment produced by Pseudomonas aeruginosa. The chloroform extraction method was employed to extract the pigment. The yield of total pigment production was 50 mg/ml. The extracted pigment was chemically characterized by UV-vis, HPLC, GC-MS, FTIR. The antifungal properties were assessed using agar well diffusion method and the results showed inhibition against four pathogens (Fusarium oxysporum (15.60 mm), Aspergillus niger (25.60 mm), Rhizoctonia solani (14.30 mm), Magnaporthe oryzae (28.00 mm) at 30 mg/ml concentration followed by 20 mg/ml. The evaluation of the biocolor as a dye was executed on different types of fabrics (velvet, wool, georgette, cotton silk) of 3 × 3 cm which was collected from the local market of Jammu. The dyed fabrics were checked for washing, rubbing, and light fastness and also checked the pigment absorption by fabrics. The antimicrobial properties of dyed fabrics were assessed using Bit diffusion method and the results showed inhibition against four human pathogens (Escherichia coli, Bacillus cereus, Klebsiella pneumonia and Staphylococcus aureus). The highest zone was shown against B. cereus of 15.60 mm (unmordant velvet fabric) and against S. aureus of 20.30 mm (mordant velvet fabric). The potential of bacterial pigments (bio pigments) as sustainable, non-toxic dyeing agents with broad applicability across textile and biomedical domains, offering a promising alternative to synthetic dyes.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13447629/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148683356","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":"Silent spreaders: multidrug-resistant and hypermucoviscous Klebsiella from animals threaten one health.","authors":"Michelle de Souza Moura Gonçalves, Cássia C da Motta, Dayanne A De Melo, Thérèsse C N Holmström, Miliane M S De Souza","doi":"10.1007/s42770-026-02023-6","DOIUrl":"10.1007/s42770-026-02023-6","url":null,"abstract":"<p><p>This study investigated the identification, antimicrobial resistance patterns, and phenotypic and genotypic traits of 30 Klebsiella isolates recovered from diverse animal species and infection sites. MALDI-TOF MS demonstrated higher accuracy in species-level identification than conventional phenotypic approaches, revealing a predominance of Klebsiella pneumoniae (80%), followed by K. variicola, K. aerogenes, and K. oxytoca. Multidrug resistance was detected in 46.6% of isolates, while 43.3% were extended-spectrum β-lactamase (ESBL) producers carrying genes such as blaTEM, blaCTX, and blaSHV. One carbapenemase-producing isolate was confirmed, and carbapenemase-encoding genes (blaOXA-48, blaNDM, blaKPC) were identified in additional strains. Notably, hypermucoviscosity was observed in four isolates, including the first report of a hypermucoviscous K. variicola from a dog. These findings highlight the presence of antimicrobial-resistant Klebsiella isolates in animal sources and support the need for integrated One Health surveillance.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13447612/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148683424","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":"Environmental and agronomic drivers of bacterial and fungal alpha diversity in crop rhizosphere: a multifactorial field study.","authors":"Katarína Ondreičková, Katarína Hrčková, Lubomír Neudert, Petr Elzner, Michal Rábek, Vladimír Smutný, Marcela Gubišová, Martina Hudcovicová, Jozef Gubiš","doi":"10.1007/s42770-026-02045-0","DOIUrl":"10.1007/s42770-026-02045-0","url":null,"abstract":"<p><p>Interactions with biotic and abiotic factors significantly impact soil microbial diversity, shaping it with varying intensities. This study investigated the effects of crop type (barley and maize), locality (Slovakia and the Czech Republic), growing year (2021-2023), seed treatment variant (control; seeds treated with fungicide; seeds coated with a superabsorbent polymer (SAP); and seeds treated with both fungicide and SAP), and repetition on microbial biomass and the alpha diversity of bacterial and fungal communities in the rhizosphere. Microbial community structure was assessed using automated ribosomal intergenic spacer analysis. The highest microbial biomass, measured as total extracted double-stranded DNA (dsDNA), was recorded in the rhizosphere of barley grown in the Czech Republic, reaching values above 40 µg dsDNA/g of dry rhizosphere soil in 2023. In contrast, the lowest microbial biomass was found in the rhizosphere of maize from the same region and year, with values as low as 5.6 µg dsDNA/g of dry rhizosphere soil. Alpha diversity analysis revealed higher richness in fungal communities than in bacterial communities, with up to 69 fungal operational taxonomic units (OTUs) and 44 bacterial OTUs detected per profile. Growing year and locality were the dominant drivers of microbial biomass and diversity, while crop type had a moderate effect. Seed treatments and experimental repetitions did not independently affect microbial diversity; however, several significant interactions among factors were detected, indicating context-dependent microbial responses. These findings highlight the complexity of rhizosphere microbial communities and emphasize the importance of temporal and spatial variability when evaluating management practices in agricultural systems.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13442804/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148677184","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":"Distribution of hepatitis B virus genotypes and demography in the general population of Karachi, Sindh.","authors":"Saba Farooq, Hana'a Iqbal, Sirmast Faiz, Farwa Ahsan, Atia-Tul-Wahab, M Iqbal Choudhary","doi":"10.1007/s42770-026-02044-1","DOIUrl":"10.1007/s42770-026-02044-1","url":null,"abstract":"<p><p>Hepatitis B is a major global burden, with 253 million infected people. There are at least ten Hepatitis B virus (HBV) genotypes and 35 subgenotypes, with distinct ethno-geographical distributions and manifest differences in their biological characteristics, display close association with clinical outcomes, severity of disease, and response to antiviral therapy. The aim of the study was to identify the predominant circulating genotypes of HBV in the population of Karachi, Sindh. A demographic assessment was conducted alongside a serological evaluation of markers specifically HBsAg, HBsAb, HBeAb, and HBcAb to determine the clinical infection profile of the study cohort. An initial molecular identification was performed by first round of PCR via specific primers P1 and S1-2 for PreS1/S2 gene. The HBV genotypes (A to F) was determined by nested PCR using primer pairs for the conserved sequence of HBV pre-S gene and S gene, and subsequently validated by phylogenetic analysis. The study findings indicated that the mean age of the study participants was 33.94 years, with a median age of 31.5 years. The percentage of HBV positive female and male were 51.5% and 48.5%, respectively. The results of this pilot study indicated that the probable predominant genotype circulating in Karachi is D, followed by B and C. Mixed infection of B, C, and D was also observed. Almost all the D positive samples were positive for HBsAg.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13433677/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148668350","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":"Disruption of ytrE attenuates methicillin-resistant Staphylococcus aureus virulence and compromises membrane integrity and oxidative stress resistance.","authors":"Jianhua Liao, Chaodan Shao, Dongli Yu, Yuechun Wang, Xiaoxia Shou","doi":"10.1007/s42770-026-02043-2","DOIUrl":"10.1007/s42770-026-02043-2","url":null,"abstract":"<p><p>Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of invasive infections, yet the genetic basis of its stress adaptation remains partially understood. This study investigates the role of the conserved membrane-associated gene ytrE in MRSA USA300 pathogenesis. While disruption of ytrE did not affect in vitro growth or biofilm formation, the ΔytrE mutant exhibited significant attenuation in a murine systemic infection model, characterized by increased host survival and reduced bacterial burdens in major organs. Phenotypic analyses revealed that loss of ytrE leads to compromised membrane integrity, impaired surface-associated motility, and heightened sensitivity to oxidative stress (H₂O₂). Furthermore, the mutant showed reduced levels of cell-associated phenol-soluble modulins (PSMs), which may contribute to the impaired colony spreading phenotype. Genetic complementation restored the major altered phenotypes observed in the ΔytrE mutant. These findings suggest that ytrE contributes to MRSA pathogenic fitness by supporting envelope homeostasis and resistance to oxidative stress. Non-essential factors involved in membrane stability may represent potential targets for future anti-virulence studies.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13433871/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148668392","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":"Duloxetine repositioning: Investigation of antifungal and antibiofilm activity against fluconazole-sensitive and resistant Candida Spp. strains.","authors":"Sarah Alves Barbosa, Dávylla Rênnia Saldanha Pinheiro, Leilson Carvalho de Oliveira, Lara Elloyse de Almeida Moreira, Vitória Pessoa de Farias Cabral, Daniel Sampaio Rodrigues, Beatriz Oliveira de Souza, Hélio Vitoriano Nobre Júnior, Livia Gurgel Do Amaral Valente Sa, Bruno Coêlho Cavalcanti, Islay Lima Magalhães, José Roberto de Oliveira Ferreira, Manoel Odorico de Moraes, João Batista de Andrade Neto, Cecília Rocha da Silva","doi":"10.1007/s42770-026-02038-z","DOIUrl":"10.1007/s42770-026-02038-z","url":null,"abstract":"<p><p>The increase in fungal infections, the limited therapeutic arsenal, and the emergence of resistance pose a global health problem. Candida spp. stand out as opportunistic pathogens that cause superficial and invasive diseases. Thus, the search for new therapeutic alternatives, such as drug repositioning, is necessary. Duloxetine (DUL), a serotonin-norepinephrine reuptake inhibitor antidepressant used to treat depression, has demonstrated antifungal activity and potentiates the effects of conventional antifungals in vitro. The objective of this study is to evaluate the in vitro activity of duloxetine (DUL) against resistant Candida spp. strains. To this end, the minimum inhibitory concentration (MIC) of DUL alone and in combination with conventional antifungals was determined in order to evaluate the type of interaction between them, as well as the minimum fungicidal concentration (MFC). The activity of DUL against mature and developing biofilms was evaluated, in addition to the possible antifungal mechanism of action. DUL showed MICs of 16 to 128 µg/mL with a fungicidal action profile, and when combined there was synergistic interaction with amphotericin B (AMB). In biofilms, DUL exhibited antibiofilm activity and enhanced AMB activity against developing, but not mature, biofilms. Mechanism of action analysis showed that DUL promoted oxidative stress, evidenced by increased reactive oxygen species (ROS) production, reduced GSH levels, mitochondrial depolarization, and phosphatidylserine externalization, suggesting the activation of the apoptotic pathway as a possible mechanism of cell death. The pro-oxidant effects of DUL were evident in C. albicans strains deficient in antioxidant defenses (cap1Δ and gpx3Δ) compared to the wild-type strain. DUL exhibited antibiofilm activity and enhanced AMB activity against developing, but not mature, biofilms.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13433714/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148668381","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":"Antimicrobial activity of Weissella cibaria strains and the contribution of organic acids against food-associated target microorganisms.","authors":"Camila Gonçalves Teixeira, Cleonice Aparecida Salgado, Tomás Gomes Reis Veloso, Sidney Rodrigues de Jesus Silva, Cecilia de Souza Costa, Solimar Gonçalves Machado, Cinzia Lucia Randazzo, Antônio Fernandes de Carvalho","doi":"10.1007/s42770-026-02029-0","DOIUrl":"10.1007/s42770-026-02029-0","url":null,"abstract":"<p><p>Weissella cibaria, a heterofermentative lactic acid bacterium, is recognized for its antimicrobial activity against a range of pathogenic microorganisms. Therefore, the objective of this study was to evaluate the antimicrobial potential of W. cibaria strains, with an emphasis on their organic acids, against target microorganisms commonly associated with milk and dairy products (Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Salmonella). To this end, this study evaluated the minimum inhibitory concentration (MIC) of cell-free supernatants (CFS) from three W. cibaria strains (W21, W25, and W42) and their 1:1:1 mixture. Furthermore, the CFS mixture was used in a cheese-simulating matrix to inhibit the target microorganisms. Using HPLC, the organic acids present in the CFS were identified and quantified. Finally, combinations of identified synthetic organic acids were tested for effective inhibition of the target microorganisms. The CFS from strains W21 and W25 and the CFS mixture exhibited better MIC, while a higher concentration of the CFS from W42 was required to inhibit the tested strains. In a cheese-simulating matrix, the CFS mixture significantly reduced the survival rate of the target microorganisms (p < 0.05). By HPLC, the organic acids detected were lactic, acetic, isovaleric, propionic, butyric, valeric, and malic acids. Strain W42 stood out for the absence of isovaleric and valeric acids, while strain W25 stood out for the absence of malic acid. A total of 127 combinations of synthetic organic acids were formulated. L. monocytogenes and Salmonella were predominantly inhibited by combinations of three acids, while E. coli and S. aureus were predominantly inhibited by combinations of 4 or 5 acids and 3 or 5 acids, respectively. The predominance of lactic, acetic, and isovaleric acids was associated with inhibition of the tested microorganisms, while valeric acid was not required for the inhibitory effect of the most effective combinations. These findings support the use of W. cibaria CFS as a potential natural antimicrobial strategy in dairy products and indicate that organic acid combinations may contribute to the inhibition of food-associated microorganisms.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13421563/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148618288","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":"Detection and characterization of a MERS-related coronavirus (Betacoronavirus cameli) in velvety free-tailed bats (Molossus molossus, Mammalia) captured in Southern Brazil.","authors":"Alexandre Sita, Micheli Filippi, Juliana Comerlato, Gabriela Espindola Birlem, Deivid de Souza da Silva, Larissa Mallmann, Vyctoria Malahyka de Abreu Góes Pereira, Meriane Demoliner, Juliana Schons Gularte, Alana Witt Hansen, Fernando Rosado Spilki, Matheus Nunes Weber","doi":"10.1007/s42770-026-02034-3","DOIUrl":"10.1007/s42770-026-02034-3","url":null,"abstract":"<p><p>Bat-borne coronaviruses are of increasing interest due to their potential for zoonotic spillover, particularly within the Betacoronavirus genus. Partial genomic sequences related to MERS-like CoV was identified in multiple hosts, including humans, camelids, and bats from the families Vespertilionidae and Molossidae. In this study, we investigated the presence of coronaviruses in 65 Molossus molossus bats captured in southern Brazil using nested RT-PCR and high-throughput sequencing (HTS). One individual (1.5%) tested positive in a rectal swab, and sequence analysis revealed the presence of a MERS-related coronavirus (Betacoronavirus cameli). Phylogenetic reconstruction based on five genomic contigs clustered the virus within the Merbecovirus subgenus, confirming its close relationship to MERS-CoV strains previously detected in bats and dromedary camels. M. molossus is a widely distributed, insectivorous bat species with synanthropic behavior, commonly roosting in urban areas and human dwellings. The detection of a MERSr-CoV in this species in southern Brazil expands the known host range of these viruses and suggests that members of the Molossidae family may serve as reservoirs. These findings underscore the importance of continuous genomic surveillance in Neotropical bats, particularly in the context of environmental changes that intensify contact between wildlife, humans, and domestic animals.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13421570/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148618351","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":"Single spore propagation of native arbuscular mycorrhizal fungi associated with Khasi mandarin and their symbiotic efficacy in maize.","authors":"Vishal Kumar Mohan, Santa Ram Joshi","doi":"10.1007/s42770-026-02041-4","DOIUrl":"10.1007/s42770-026-02041-4","url":null,"abstract":"<p><p>Arbuscular Mycorrhizal Fungi (AMF) are important members of the soil microbiome that form symbiotic relationships with plant roots, improving nutrient uptake and stress resilience. In the present study, native AMF associated with the rhizosphere of Khasi Mandarin (Citrus reticulata Blanco) were isolated using the wet sieving and decanting method. Trap culture was used to increase the number of native AMF spores. Healthy spores were identified and used for single-spore inoculation to establish single-spore-derived cultures. Molecular identification of the AMF isolates was performed by amplification of the 18 S rDNA region. A controlled pot experiment was conducted to assess the effects of the obtained pure cultures on plant growth. Inoculated maize plants showed significant improvement in root and shoot biomass. This study focuses on evaluating the potential of native AMF isolates associated with Khasi mandarin and their use as cross-inoculants to develop biofertilizer that promote the growth of non-host plants.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13421532/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148618273","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":"Evaluation of genomic characteristics of Escherichia coli associated with bovine mastitis and the potential utility of alternative antimicrobial methods.","authors":"Jônathas Moreno Silva de Souza, Gabryel Bernardo Vieira de Lima, Daniela Dos Santos Cassimiro, Sheila da Silva, Thiago de Jesus Sousa, Danillo Sales Rosa, Renata de Faria Silva Souza, Fernando Antônio Gomes da Silva Júnior, Helinando Pequeno de Oliveira, Sílvia Cristina Osaki, Vasco Ariston de Carvalho Azevedo, Bertram Brenig, Flavia Figueira Aburjaile, Mateus Matiuzzi da Costa","doi":"10.1007/s42770-026-02040-5","DOIUrl":"10.1007/s42770-026-02040-5","url":null,"abstract":"<p><p>Mastitis is a disease that affects dairy cattle and can be caused by multidrug-resistant Escherichia coli, causing losses to the agricultural sector. To address this, research into new substances with antimicrobial activity is crucial. Thus, the objective of this study was to evaluate the efficacy of extracts of Commiphora leptophloeos, Amburana cearensis, Agave sisalana, and highly soluble polypyrrole (Hs-PPy) against E. coli isolates. Eight E. coli isolates from bovine mastitis and a standard strain were used. The presence of efflux pumps was investigated by ethidium bromide extrusion. Sequencing was performed on the Illumina HiSeq 2500 platform using a 2 × 150 bp library with quality assessed via FastQC and assembly completed using Unicyler. Genome annotation and the identification of resistance and virulence genes were carried out using PROKKA and PanViTa, respectively. Species confirmation as E. coli was achieved via Jspecies and pyANI public genomes from NCBI. Finally, antimicrobial activity was determined by broth microdilution. Among the natural products tested against the isolates only A. cearensis showed antibacterial activity, with a concentration of 12,500 µg/mL, whereas Hs-PPy showed activity at 250 µg/mL. The isolates tested positive for the presence of efflux pump genes, but only 3 isolates expressed the mechanism in vitro. The natural products were not effective in eliminating the bacteria. Hs-PPy was the only compound that demonstrated bactericidal activity against the bacteria, proving to be an alternative for bactericidal action, even in the presence of genes that inhibit its action against a wide variety of compounds.</p>","PeriodicalId":9090,"journal":{"name":"Brazilian Journal of Microbiology","volume":"57 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13421616/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148618265","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}