Brazilian Journal of Microbiology最新文献

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.

The emergence and spread of Extended-spectrum β-lactamase (ESBL) producing avian pathogenic Escherichia coli (APEC) in poultry farms pose a significant challenge for the scientific community. The presence of APEC in poultry farms is linked to its ability to form biofilms, which is worsened by various virulence factors and drug resistance, enabling bacteria to survive in various environments. The present study investigated the prevalence of ESBL-producing APEC isolates from waste samples collected from poultry farms. A total of thirty samples were collected from ten poultry farms. One metallic sheen colony from Eosin methylene blue agar from each sample was used to isolate APEC. This study revealed that all twenty-eight E. coli isolates resisted at least one antibiotic, reflecting a high resistance rate. Isolates that resisted one or more antibiotics were further screened for APEC virulence genes via conventional polymerase chain reaction. The analysis revealed that 38% of the isolates were APEC strains, while the remaining 63% were non-APEC strains. Most APEC isolates harboured more than one beta-lactamase gene, with the prevalent ESBL genotype combination being blaSHV and blaTEM. Phenotypic confirmation using the Ceftazidime/Ceftadime + Clavulanic acid revealed that one isolate was found to produce the ESBL enzyme. To tackle this issue, it is important to implement preventative measures effectively, aiming to decrease the prevalence of ESBL-producing APEC and its transmission to humans via poultry products.

Immunomodulation by Lacticaseibacillus sp. is a subject of increasing interest; however, the time-period of administration for its immunomodulatory effect to occur is not well established. In the present study, we examined the effect of L. casei CB054 on cytokine transcription ex vivo in mouse splenocytes and the bacterial microbiota profile at 24, 48, and 72 h after oral administration of 1 × 10⁶ UFC/g viable L. casei. Cytokine mRNA transcription was evaluated for IL4, IL10, IL12, IFNɣ, and TNFα at different time points by qPCR. Microbiota was analyzed using fecal samples collected at zero, 24, 48, and 72 h after L. casei administration. A significant upregulation (p < 0.05) for IL10 at 72 h and IL12 at 48 and 72 h in supplemented groups was observed. IFNɣ and TNFα showed similar significant upregulation patterns (p < 0.05) at all time points evaluated, whereas IL4 showed significant transcriptional downregulation during the supplementation period. After DNA extraction, the V3-V4 region from the 16 S rRNA gene was sequenced, and reads were processed using the Divisive Amplicon Denoising Algorithm (DADA2). Bacteroides and Lactobacillus were the most abundant genera in the supplemented groups. At the phylum level, Actinobacteria and Bacteroidetes were reduced to 24 h and 48 h compared to 0 h, whereas the phylum Firmicutes significantly increased at 72 h compared to 0 h. In conclusion, evidence suggests that L. casei CB054 has a specific, time-dependent immunomodulatory effect on splenocyte cytokine transcription, modulating the bacterial communities of the mouse gut microbiome.

Chaetomorpha antennina is a green alga and is known for its medicinal properties. Endophytes are microbes capable of synthesizing bioactive compounds which kills the pathogens without harming the host. The current study was aimed to detect the presence of endophytic bacteria that could inhibit bacterial human pathogens. The isolate VITSSSTJ4 produced secondary metabolites that restrained the development of Bacillus cereus, Pseudomonas aeruginosa, and Escherichia coli with a zone diameter of 19 ± 0.67, 13 ± 0.67 and 12 ± 0.67 mm respectively, in n-hexane extract. Additionally, SPE and UPLC were used to purify the extract and a peak was detected in UPLC at a retention time of 7.741 min. Further, FT-IR technique was employed to detect the functional groups such as C-O, O-H, N=C=O, C=C, C-H, O-H, and N-H. Gass Chromatography-Mass Spectrometry (GC-MS) confirmed molecular mass of the lead molecule to be 369.1638 g/mol and was identified to be 1-(4-Acetamidoanilino)-3,7-dimethylbenzo [4,5]imidazo[1,2-a]pyridine-4-carbonitrile. The effective isolate VITSSSTJ4 was found to be the closest neighbour of Bacillus stercoris in 16S rRNA gene sequencing, and the rod-shaped cell structure of VITSSSTJ4 was detected by scanning electron micrographs. Molecular docking revealed that the lead molecule had a substantial binding interaction with the methyltransferase component with a binding affinity of -7.7 kcal/mol.

Plant-microbe interactions play a critical role in maintaining plant health, enhancing soil fertility, and sustaining ecosystem functionality. Agave americana (Asparagales, Asparagaceae, L.), a crassulacean acid metabolism (CAM) species known for its remarkable drought tolerance and diverse industrial uses, represents a valuable model for exploring the ecological and functional dynamics of these associations. This study explores the diversity and functional potential of bacterial communities associated with A. americana and their role in promoting plant growth. A combination of culture-dependent techniques and metagenomic sequencing was employed to isolate and characterize rhizospheric and endophytic bacteria. Prominent bacterial genera identified included Acinetobacter, Bacillus, Rhizobium/Mesorhizobium, and Microbacterium. Metagenomic analyses revealed a high abundance of Actinobacteria, Proteobacteria, and Chloroflexi, highlighting their roles in nutrient cycling and organic matter decomposition. Plant growth-promoting assays demonstrated that Rhizobium sp. 34 A produced significant levels of indole-3-acetic acid (IAA), enhancing nutrient availability and plant growth. Mesorhizobium sp. 28 A had the greatest overall impact, significantly increasing total fresh weight, chlorophyll content, and sugar profiles, surpassing the effects of chemical fertilizers. Furthermore, Bacillus sp. T12C12, in combination with other plant growth-promoting bacteria (PGPB), exhibited the highest nitrogenase activity, as measured through acetylene reduction assays (ARA). These findings suggest that bacterial inoculants can enhance the nutritional and agronomic value of Agave species, which are of significant agro-industrial and food importance, providing a sustainable alternative to chemical fertilizers. This study offers valuable insights into sustainable agricultural practices by leveraging microbial communities to enhance crop productivity and resilience.