Brazilian Journal of Microbiology最新文献

Lignocellulosic materials used in the food industry as containers or packaging can suffer fungal biodeterioration. For this reason, the aim of this study was to evaluate the superficial growth of Aspergillus ellipticus on lignocellulosic materials of food containers and packaging. A strain of A. ellipticus was selected for its high productivity of lignocellulolytic enzymes. Fragments the diameter of a 110 mm Petri dish were cut from six types of lignocellulosic materials used as supports: coated cardboard, uncoated cardboard, corrugated cardboard, kraft paper, cupcake wrapper and Whatman 5 filter paper (positive control). The thickness (µm) and initial pH were measured for each material by contacting 2 g of material with 100 mL of distilled water at 15 °C and 40 °C and 10 µL of a spore suspension (10⁶ spores/mL) was inoculated and incubated at 32 °C and 87% relative humidity in a desiccator with saturated barium solution. For 21 days, the diameter of the colony (mm) was measured growing on lignocellulosic materials. The pH of the materials was between 7.2 and 7.4, considering them neutral materials. The growth of the fungal colony was between 2 mm and 38.6 mm, being higher on filter paper, followed by kraft paper, corrugated cardboard, uncoated cardboard, coated cardboard and cupcake wrapper. It is concluded that fungal biodeterioration of lignocellulosic packaging material for food can occur in conditions similar to those of tropical climates.

The present research was intended to identify the bioactive molecules from the ethanolic extract of T. arjuna leaf against a diverse array of Vibrio species by means of a bioassay-guided fractionation. The antibacterial efficacy of compounds was assessed by the microdilution technique, while the brine shrimp mortality assay was employed to determine their toxicity. Following an initial screening, the ethanol extract underwent silica gel chromatography, succeeded by reversed phase HPLC, to identify the most potent fraction towards V. parahaemolyticus. Through further UHPLC-orbitrap-ion trap mass spectrometry, three likely compounds were identified, demonstrating broad-spectrum efficiency against several Vibrio species, including V. parahaemolyticus, V. harveyi, V. alginolyticus, V. vulnificus, and V. anguillarum. Among the bacteria, V. vulnificus was the most sensitive species (IC₅₀ ranged from 17 to 25 µg/mL) while V. harveyi was the most resistant species (IC₅₀ > 200 µg/mL) for the compounds. The toxicity test findings indicated that the compounds tested were not detrimental to shrimp. This is one of the most important reports identifying these specific fatty acid derivatives with anti-Vibrio activity in shrimp. The findings of the current study suggest that the leaf extract of T. arjuna may include bioactive compounds that might serve as potential complementary or prophylactic agents for the treatment of pathogenic Vibrio species in shrimp aquaculture.

Bovine Viral Diarrhea (BVD) significantly impacts cattle production and reproduction, causing substantial economic losses in the livestock industry. The etiological agent is a virus from the Flaviviridae family, genus Pestivirus, which is globally distributed with a prevalence of 60-85% in South American cattle herds. A relevant characteristic of this disesase is to produce immunotolerant animals (persistently infected - PI) that would not detected and eliminate a large amount of viruses in the herd, being the primary source of viral transmission. Early viral detection in the herd would allow a more effective control program. Here, we compared traditional molecular techniques (conventional PCR and Real-time PCR) to one of the latest generation (droplet digital PCR, ddPCR) which has shown significant advantages over the aforementioned ones. Serum samples from 46 animals, previously tested for BVD using conventional PCR and including both positive and negative results, were used for this comparison. Additionally, the NADL BVDV reference strain and a synthetic plasmid were used as positive controls, while non-template controls were used as negative controls. ddPCR showed higher sensitivity and precision for the detection and quantification of BVDV. ddPCR Limit of Detection was 0.24 copies/µL (286.3 × 10^-6 ηg/µL) for NADL BVDV reference strain, outperforming previous methods by an order of magnitude. The results showed that droplet digital PCR is a robust tool, with higher sensitivity, specificity and reproducibility, and it can be helpful when used in BVD control programs using pools of serum or bulk milk tanks.

In this study, we characterized 86 plant growth-promoting bacterial strains belonging to the genus Nitrospirillum, isolated from diverse host plants and geographic regions. We investigated their evolutionary relationships through phylogenetic analyses of the 16S rRNA and recA genes, complemented by phylogenomic approaches incorporating genomic similarity metrics, such as ANI and dDDH. The classification of type strains was further supported by in silico analyses of chemotaxonomic markers, particularly genes involved in fatty acid biosynthesis and elongation, phospholipid and quinone production, and nitrogen fixation (nifHDK operon). Phenotypic and chemotaxonomic characterization was performed using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, fatty acid methyl ester (FAME) profiling, and physiological assays. These included evaluations of nitrogen fixation capacity, antibiotic resistance, carbon source utilization, and enzymatic activities. This integrative approach provided detailed insight into the characteristics and diversity of the studied strains. Phylogenetic and genomic analyses revealed six novel taxa within the genus Nitrospirillum, in addition to the previously described species N. amazonense, N. iridis, and N. viridazoti. The distinctiveness of these new lineages was supported by both genomic metrics and phenotypic traits. All novel strains also exhibited activity of nitrogenase enzyme, confirming their nitrogen-fixing ability under in vitro conditions. Based on these findings, we propose the formal description of six novel species: Nitrospirillum bahiense sp. nov. (= BR 11865^T, = UCCCB 233^T), Nitrospirillum guanabarense sp. nov. (= BR 11163^T, = UCCCB 228^T), Nitrospirillum guaranorum sp. nov. (= BR 11164^T, = UCCCB 229^T), Nitrospirillum karajorum sp. nov. (= BR 11752^T, = UCCCB 231^T), Nitrospirillum goiasense sp. nov. (= BR 11828^T, = UCCCB 232^T), and Nitrospirillum pindoramense sp. nov. (= BR 11622^T, = UCCCB 230^T).

The global spread of multi-drug-resistant bacteria, including strains resistant to both polymyxin and carbapenems, poses a significant threat to public health, highlighting the need to develop new antimicrobial agents. This study assessed the antimicrobial potential of cinnamaldehyde, alone and in combination with antibiotics, against carbapenem-polymyxin-resistant K. pneumoniae strains (CPR-Kp). The antimicrobial activity was assessed through minimum inhibitory concentration (MIC), checkerboard assay, and survival curve analysis. Cinnamaldehyde showed inhibitory effects (MIC 281 µg/mL), and when combined with polymyxin B, resulted in synergistic effects, effectively overcoming resistance to both polymyxin and carbapenem. Notably, cinnamaldehyde (70 µg/mL) combined with polymyxin B (1 µg/mL) led to a significant reduction in the MIC of polymyxin B, from 64 µg/mL to 1 µg/mL, with a fractional inhibitory concentration index (FICI) of 0.26, indicating synergy. The ZIP synergy score analysis further corroborated these findings, revealing a global synergy score of 32.728, with the highest values observed at cinnamaldehyde concentrations of 70-140 µg/mL in combination with polymyxin B. Similarly, in vivo the combination of cinnamaldehyde (30 or 100 mg/kg) with polymyxin B (2 mg/kg) significantly reduced bacterial loads in blood and peritoneal lavage (p < 0.0001) and improved survival rates. These findings underscore the efficacy of cinnamaldehyde as an adjuvant to polymyxin B in treating infections caused by CPR-Kp. The observed synergistic effect suggests that cinnamaldehyde as a pivotal component in future therapeutic formulations, providing a promising avenue for further research in combating antimicrobial resistance.

Papillomaviruses (PV) are significant agents capable of inducing simple, multiple, and/or proliferative lesions in the dermis and epidermis of animals, known as cutaneous papillomatosis. These lesions can be benign or malignant and have been identified in various hosts, including mammals, birds, reptiles, and fish. PVs are strictly species- and tissue-specific, although some established and unusual cases of cross-infection, such as BPV in equine sarcoids, have been reported. Sarcoids are horses' most common skin tumors, which can be locally aggressive and cause significant clinical signs. It is recurrently associated with Bos taurus papillomavirus (BPV) and, more recently, Ovis aries papillomavirus (OaPV). Interestingly, OaPV2s, initially identified in sheep, have been detected in other species, such as horses, cattle, and pigs. Therefore, the present study aimed to detect and sequence PVs in an equine sarcoid through rolling circle amplification followed by high-throughput sequencing (RCA-HTS) on the Illumina MiSeq platform. Sequencing yielded 387,923 reads and 17 contigs classified as Deltapapillomavirus genus. A complete BPV1 genome, with 99% coverage, was sequenced, and partial E1 and L1 genes of OaPV2 were detected. Histopathological analysis revealed fibroblastic sarcoid, which has been associated with BPV1 and OaPVs. Our results agree with recent BPV and OaPV2 association observations in sarcoid lesions in equine and swine. This broad host range of OaPVs deserves attention, as it may indicate potential interspecies transmission that is not yet fully understood, especially in coinfections, which could influence viral dynamics, transmission patterns, and disease outcomes. Until now, only OaPV1, 3, and 4 had been detected in equine sarcoids; thus, this is the first detection of OaPV2 in an equine sarcoid. In conclusion, OaPV2 should be considered a potential etiological agent of sarcoids, particularly in association with BPV1.

Streptococcus equi subsp. equi (S. equi) is the etiological agent of strangles, a contagious equine disease characterized by lymph node abscess and respiratory complications. To clarify the epidemiology and virulence factors of isolates, this study demonstrated phenotypic and genotypic differences between S. equi obtained from nasal secretions and lymph node aspirates of clinical strangles cases. Additionally, circulating alleles were differentiated through sequencing of the 5' end of the seM gene. A total of 23 clinical isolates collected from horses with strangles over the past decade were analyzed for phenotypic characteristics such as colony morphology, sugar fermentation, capsule production, biofilm formation, and antimicrobial susceptibility, as well as genotypic features. The analysis revealed phenotypic variability, particularly differences in sugar metabolism and capsule expression associated with colony morphology. Most isolates exhibited weak biofilm formation and susceptibility to cephalothin, ceftiofur, and streptomycin, while resistance to tetracycline was most common. Sequencing of the N-terminal region of the seM gene identified four alleles: seM-115, seM-158, seM-270, and seM-271. Of these, only seM-115 had previously been reported in Rio Grande do Sul State (southern Brazil). Phylogenetic analysis showed distinct clustering patterns, especially among the newly detected alleles (seM-270 and seM-271). These findings highlight the importance of integrated phenotypic and genotypic analyses to understand the diversity and potential virulence of circulating S. equi strains.

Reproductive diseases in swine are responsible for important losses in pig farming. Within this context, stillbirth is one of the major causes of productive losses and sow culling. This is a complex condition, in which definitive diagnosis is difficult due to a plurality of associated factors. The maternal intestinal microbiota has been gaining attention, but there are still a low number of studies on this subject. In the present study the intestinal bacterial microbiota and its metabolic pathways were assessed in 68 sows with (n = 36) and without (n = 32) stillbirths from a farrowing-to-wean commercial pig farm from Southern Brazil. Some opportunistic pathogens were enriched in the stillbirths' group such as bacteria from the genera Odoribacter and UCG-001; while in the group without stillbirths, bacteria from the family Oscillospiraceae and the genus Faecalibacterium were enriched; these bacteria are candidates for next generation probiotics in humans, making them also promising for future studies with probiotics in swine farming. Moreover, two metabolic pathways were inferred as enriched, one in each group, both related to the maintenance of the bacterial cell wall, with no obvious association with the occurrence of stillbirths. The data obtained in the present study characterized the intestinal microbiota of sows in the studied region, allowing a better understanding of their importance in animal health.

This study aims to examine the frequency and antimicrobial sensitivity of Enterobacterales isolated from macaws in zoos in Northeastern Brazil. Using the following methodology, 97 cloacal swabs were collected from nine macaw species housed in eight zoological institutions across six states in Northeastern Brazil. Samples were collected using Stuart medium, pre-enriched in peptone water, and then enriched in Brain-Heart Infusion, Selenite Cystine, and Rappaport Vassiliadis broths. We then streaked them on MacConkey agar, Eosin Methylene Blue agar, Brilliant Green agar, and Salmonella-Shigella agar. Colonies exhibiting unique morphologies underwent bacterial tests for identification. Any samples suspected of containing Salmonella were sent to the Oswaldo Cruz Foundation for serotyping. We used the Kirby-Bauer test for the antimicrobial sensitivity test. A total of 123 strains belonging to the order Enterobacterales were isolated from 81 (83.5%) cloacal swab samples from macaws, with 16 bacterial species identified. The most frequently observed species were Escherichia coli (64.0%), Citrobacter freundii (15.5%), and Serratia liquefaciens (14.4%). The antibiotics showing the highest resistance were fosfomycin (16.3%), followed by tetracycline (13.9%), and amoxicillin with clavulanate (12.2%). However, the strains demonstrated substantial sensitivity to meropenem (100.0%), tobramycin (98.4%), and chloramphenicol (97.7%). We observed multi-resistance in 9 (7.3%) of the isolates, with E. coli 5/9 (55.5%) proving to be the most prevalent among the multi-resistant strains. These findings indicate that macaws in Northeastern Brazilian zoos may harbor antimicrobial-resistant, potentially zoonotic enterobacteria, underscoring the need for captive wildlife monitoring. The findings have implications for animal, human, and environmental health, reinforcing the importance of One Health strategies.

Brucellosis is among the most widespread zoonotic diseases globally, affecting multiple domestic animal species. We report the first isolation of Brucella suis from a vaginal swab collected from an aborted cow in India. The isolate (VS1) was confirmed as B. suis bv. 1 by biochemical assays and species-specific PCR. Whole genome sequencing analysis of the VS1 isolate revealed a 32,81,903 bp genome with a guanosine and cytosine (GC) content of 57.29%. Multilocus sequence typing (MLST) 9-gene, 21-gene, and core genome MLST (cgMLST) schemes identified sequence types ST14, ST75, and ST1054/1075, respectively. Comparative genomics involving publicly available B. suis genome sequences showed conservation of key virulence genes. The genome B. suis strain 1330 was used to identify the single nucleotide polymorphisms (SNP) in study genomes and 63 SNPs were identified in the virulence-associated genes. The study indicates that B. suis biovar 1 can infect cattle, and likely contributes in the epidemiology and control of bovine brucellosis in India.