Brazilian Journal of Microbiology最新文献

Antimicrobial resistance (AMR) in Staphylococcus aureus is a growing concern in poultry production, driven by the extensive use of antimicrobials for metaphylaxis, prophylaxis, and growth promotion. This study investigated genes linked to β-lactam resistance and multidrug efflux in S. aureus isolated from commercial laying hens and broilers in Pernambuco, Brazil. A total of 200 samples obtained from 100 birds (100 tracheal swabs and 100 cloacal swabs) were collected from 20 flocks. Bacterial DNA was extracted and subjected to PCR to confirm S. aureus and to detect blaZ, mecA, mecC, norA, norC, msrA, and tet38. S. aureus was identified in 5% (5/100) of the commercial birds tested, all from laying hens. Among these isolates, 20% (1/5) carried mecC and blaZ, 100% were positive for norA and norC, and 60% (3/5) for msrA. mecA and tet38 were not detected. These findings underscore the potential dissemination of S. aureus harboring resistance genes in poultry environments and highlight S. aureus as a reservoir of antimicrobial resistance in poultry production, with implications for animal and public health. Therefore, continuous surveillance and the prudent use of antimicrobials in animal production systems are necessary. Although efflux pump and mecC genes have been documented in Brazilian livestock, reports in poultry are scarce. These findings support the inclusion of these genetic determinants of resistance in national surveillance of antimicrobial resistance in poultry.

Usable water sources are at risk due to improper disposal and chemical contaminants. A potentially effective solution is using a biofilter based on bacterial cellulose (BC) to treat wastewater. This research aimed to produce BC using Komagataeibacter hansenii (ATCC 23769) from by-products to develop an efficient biofilter for removing microscopy dyes. To achieve this, K. hansenii was cultivated in three culture media using industrial co-products: control: mannitol (CT), crude glycerol + corn steep liquor (CGC), and coffee husk + corn steep liquor (CHC). Chromatography analysis assessed compound production during fermentation and BC production. Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy were conducted to analyze the chemical and physical properties of the BC. The findings revealed that the substrate significantly affects BC production by K. hansenii. BC produced with crude glycerol (CGC) shows superior tensile strength, Young's modulus, and nanofibril compaction, making it ideal for biofilters. Additionally, BC from CGC demonstrates higher efficiency in reducing biological and chemical oxygen demand in water treatment. The versatility of BC allows for its application in biofilters, medical dressings, cosmetics, and food packaging. Choosing a suitable substrate and purification process, mainly using CGC, is crucial for optimizing BC's yield and functional properties.

The present study aimed to investigate bacterial endophytes from different tissues of Aconitum nagarum, a threatened and medicinally important plant native to North East India, and to evaluate their antimicrobial potential. A total of 47 bacterial isolates were obtained from leaf, stem, and tuberous root samples, with the highest colonization frequency observed in leaf tissues (32.50%). Based on morphological, microscopic, and biochemical characterization, the isolates were categorized into six bacterial genera: Actinomycetes, Bacillus, Pseudomonas, Serratia, Streptococcus, and Streptomyces. All isolates were screened for antimicrobial activity against a panel of clinically significant pathogens: Pseudomonas aeruginosa (ATCC 9027), Klebsiella pneumoniae (ATCC 1705), Bacillus subtilis (ATCC 6051), and Candida albicans (MTCC 227). Among them, two isolates identified as Bacillus amyloliquefaciens and Bacillus siamensis exhibited significant antimicrobial activity, showing the highest zones of inhibition against K. pneumoniae, ranging from 18.04 ± 0.42 mm to 20.03 ± 0.63 mm. Crude metabolites of these isolates were extracted using ethyl acetate and characterized by GC-MS analysis. GC-MS analysis of B. amyloliquefaciens extracts revealed major compounds such as tetradecanoic acid, 4-tert-amylphenol, pyrrolo[1,2-a] pyrazine-1,4-dione, and benzeneacetic. In contrast, the extracts of B. siamensis contained cyclotrisiloxane, hexamethyl, 3-methylpentanoic acid, 2-methylbutanoic acid and 2-ethylheptanoic acid as principal compounds. While many of these compounds are known for their antimicrobial properties, the bioactivity of some remains to be elucidated. This study highlights the potential of endophytic bacteria from A. nagarum as a promising source of novel antimicrobial metabolites. Further in-depth investigations could lead to the discovery of new bioactive compounds with therapeutic applications.

The search for microbial cells from different sources is a crucial strategy for discovering new strains with biotechnological potential. Leaf litter fungi, which decompose organic matter, and symbiotic termite bacteria, which digest cellulose, can be harnessed for the development of biotechnologies focused on nutrient recycling, biofuel production, and organic waste treatment. The precise identification of these strains allows the use of their biological capabilities, promoting innovative and sustainable solutions to environmental challenges. In this study, filamentous fungi and bacteria recovered from soil with leaf litter and termite guts were characterized using an integrative taxonomy approach, including classical morphology, ribosomal RNA gene sequencing, MALDI-TOF MS, and FTIR. A total of nine filamentous fungi and nine bacteria were identified. After taxonomic analysis, the bacterial strains were identified as belonging to Rossellomorea marisflavi (n = 2), Bacillus subtilis (n = 2), B. amyloliquefaciens (n = 2), B. cereus (n = 1), Priestia megaterium (n = 1), and Pseudomonas azotoformans (n = 1). The fungal species were identified as Talaromyces mycothecaei (n = 3), Aspergillus fumigatus (n = 1), A. tubingensis (n = 1), A. hiratsukae (n = 1), Trichoderma sp. (n = 1), T. harzianum (n = 1), and Coniochaeta velutina (n = 1). This may be the first report of the isolation of Rossellomorea from the gut microbiome of termites. The results showed that the use of an integrative approach for the taxonomic characterization of microbial strains recovered from environmental samples can improve the accurate identification and understanding of microbial species associated with different environments, such as the termite gut and litter.

This manuscript describes the evaluation of the photoinactivation of cationic meso-tetra(pyridyl)porphyrins combined with cisplatin as photosensitizers (PS) for the photodynamic inactivation of Rapidly Growing Mycobacteria (RGM) strains. Two porphyrin derivatives, 3-cis-PtTPyP and 4-cis-PtTPyP, were synthesized according to methodologies previously described in the literature. The Antimicrobial Photodynamic Therapy (aPDT) experiments were conducted on different RGM strains, including Mycobacteroides abscessus subsp. abscessus (ATCC 19977), Mycolicibacterium fortuitum (ATCC 6841), Mycobacteroides abscessus subsp. massiliense (ATCC 48898), and Mycolicibacterium smegmatis (ATCC 700084), using appropriate concentrations of PS under conditions of exposure to a white-light source for 90 min (irradiance of 50 mW cm^‒2 and a total light dosage of 270 J cm^‒2). The results showed that the meta-isomeric porphyrin (3-cis-PtTPyP) was more photo-effective, significantly reducing the concentration of viable mycobacteria and inducing morphological, mechanical, and electrostatic changes in the bacterial structure. Combining photoinactivation with antimicrobials resulted in synergistic and additive effects, suggesting that this porphyrin can act as a therapeutic adjuvant or even a substitute for the conventional treatment of mycobacterial diseases. The observed photoinactivation profile, with rapid and effective bactericidal action, reinforces this PS class's potential for applications in several fields.

Malignant Catarrhal Fever (MCF) is caused by a group of gammaherpesviruses in the genus Macavirus. The virus is transmitted via nasal shedding from adapted hosts, such as sheep, which do not develop the disease, to non-adapted hosts such as cattle, pigs, bison, and deer, which can develop an often-fatal form of the disease. There is currently no specific treatment or vaccine available to control MCF, and the resulting losses significantly affect livestock industries worldwide. To assess the seroprevalence of MCF in southern Brazil, blood samples were collected from sheep and cattle reared simultaneously on twenty farms in the western region of Rio Grande do Sul state. A competitive enzyme-linked immunosorbent assay was used to detect specific antibodies to MCF viruses, and the prevalence was calculated for each herd or flock based on the total number of samples analyzed. We found seropositive sheep in every flock evaluated, and a prevalence of 89.8%. Among cattle herds, 5.2% of the animals tested were positive. Although no clinical cases were observed during the study, the management practices used on these farms, combined with the high prevalence of seropositive sheep, represent a potentially significant risk for cattle in the region. This work provides insights into the epidemiology of MCF in southern Brazil and supports efforts to improve strategies for controlling viral transmission and disease in cattle.

Feline leukemia virus (FeLV) is a retrovirus associated with a variety of clinical conditions, including either regenerative or non-regenerative anemia. The high mutation rate of retroviruses promotes the formation of quasispecies - populations composed of multiple genetically related haplotypes - which drives the evolution of the viral population within a host and can impact on disease development. This study investigated the intra-host diversity of proviral FeLV and evaluated their impact on the hematological parameters in naturally infected cats. Twenty-seven blood samples from FeLV-positive cats were analyzed. Total DNA was extracted, and the complete env gene was amplified by PCR, followed by next-generation sequencing (NGS). Raw sequence data were quality-checked, trimmed, and aligned to the FeLV SU reference sequence. Quasispecies with frequencies above 5% were inferred using CliqueSNV v2.0.3, phylogenetic reconstruction was performed with IQ-TREE v1.6.12 and recombinant sequences were identified using SimPlot v3.5.1. A remarkable variability in quasispecies composition was observed among infected cats. While 13 animals (48.1%) harbored infections driven by a single haplotype, others (n = 14) exhibited a much more complex viral landscape, with five or more distinct haplotypes detected. In samples with greater viral diversity, quasispecies frequencies were more evenly distributed. In the phylogenetic reconstruction, most quasispecies sequences isolated from the same host clustered together in well-supported clades within the FeLV-A lineage. Notably, one exception was identified as a FeLV-A/enFeLV recombinant. Additionally, five other recombinant quasispecies were detected. Analysis of hematological parameters showed no significant correlations between the number of haplotypes and the presence of anemia (regenerative or non-regenerative). However, classifying animals by their lymphocyte values' adherence to normal reference ranges revealed a statistically significant difference in the number of viral haplotypes detected between groups (p = 0.04). Additionally, a negative binomial regression indicated that life stage had a positive trend in its relationship with the number of proviral quasispecies (p = 0.0593), indirectly suggesting that a higher number of quasispecies tends to be observed in more advanced disease stages. Although not statistically significant, the result suggests a potential relationship that warrants further investigation. This study, therefore, indicates that the number of intra-host quasispecies can be influenced by both the duration of infection and alterations in the immune response in naturally FeLV-infected cats.

An outbreak of bovine viral diarrhea virus (BVDV) in a herd of 218 beef cattle resulted in 15 late-term abortions and the birth of two weak calves. Neonate 1, at 28 days of age, exhibited ataxia and paresis, while Neonate 2, at one day of age, was underdeveloped. Neonate 1 presented with cerebellar hypoplasia, hydrocephalus, and porencephalic cysts. Histological examination revealed foliar dysgenesis and ectopic Purkinje neurons. Neonate 2, weighing 7 kg at birth, showed no histologic lesions. A single fetus at six months was necropsied and showed no gross lesions. However, histopathology revealed multifocal lymphoplasmacytic inflammation. Tissue samples from the neonates and fetus were tested for BVDV by RT-PCR, yielding negative results. Brain tissue was tested by RT-PCR for Simbu serogroup viruses and by PCR for Neospora caninum and Toxoplasma gondii, all of which returned negative results. The entire herd was subjected to serum sampling for BVDV testing by RT-PCR. Six calves tested positive in all three consecutive rounds of testing, while one calf tested positive only once. Sera from the seven RT-PCR positive calves were subsequently tested by ELISA for antigen detection, with six testing positive. They were also tested by ELISA for antibody detection, with two calves showing seropositivity. Amplification products from three samples were submitted for Sanger sequencing and phylogenetic analysis, which identified BVDV-1b with 100% homology among the three sequences and a high similarity to Chinese strains. This study reports an outbreak of persistent infection by BVDV-1b in southern Brazil, with associated congenital malformations and reproductive losses.

The expanding beer market and the need for innovation in the sector has driven scientific research to find novel, non-conventional aromatic yeast strains. In this context, Saccharomyces cariocanus UFRJ 50816^T, isolated from remnants of the Atlantic Forest in Rio de Janeiro, was later found to be able to ferment sugars present in beer wort, producing a beverage with unique aromas. As a result of sequential propagation in beer wort, several derived strains (G01, S01 and D01) were obtained by spontaneous adaptation. Saccharomyces cariocanus G01 is a derivative strain that ferments maltose better than its parental strain. Here, we present the first whole-genome sequence for the species S. cariocanus. Phylogenetic identification was performed via multilocus sequence analysis, using five genomic regions: ITS, SSU, LSU, TEF1 and RPB2. The strain's maltose fermentation ability was confirmed through Durham tube fermentation assays, and supported by the identification of key MAL genes in its genome. Additionally, genes related to the production of aroma and flavor compounds were identified, including ATF1, ATF2 and IAH1, associated with a banana-like aroma, and PAD1 and FDC1, which contribute to a clove-like aroma. Although based solely on genomic inference, these findings are consistent with the banana and clove-like aromas perceived in a brewed pilot batch produced with S. cariocanus G01. Given these characteristics, S. cariocanus G01 shows strong potential for the development of beers as well as Brazilian cachaças.

Escherichia coli is a clinically relevant zoonotic pathogen with significant impacts on both food safety and animal/human health. This study characterized the pathogenicity and genomic features of sequence type (ST) 83 E. coli isolated from liver samples of deceased chicken in China, along with its potential for zoonotic transmission. A total of eight ST83 E. coli isolates were obtained from liver samples. Pathogenicity tests demonstrated the isolates' virulence in chickens, inducing significant pathological lesions indicative of poultry health risks. Genomic analysis indicated an alarming antimicrobial resistance gene (ARG) profile, including tet(X4) and bla_NDM-5, among ST83 E. coli strains in China. The ARGs were strongly associated with mobile genetic elements (MGEs) such as IncQ1 plasmids and insertion sequences (ISs) IS903, highlighting their co-transmission potential through horizontal gene transfer. In addition, core genome phylogeny and pangenome analysis identified minimal genetic divergence between human- and animal-derived strains. This close relationship, evidenced by shared accessory genes and small SNP differences, suggests potential zoonotic transmission. Collectively, these findings indicate that ST83 E. coli is a dual-threat pathogen, being not only a virulent pathogen in poultry but also a One Health concern due to its potential for zoonotic transmission and antimicrobial resistance dissemination.