Honeybees play a vital role in the ecological environment and agricultural economy. Increasing evidence shows that the gut microbiome greatly influences the host’s health. Therefore, a thorough understanding of gut bacteria composition can lead to the development of probiotics specific for each development stage of honeybees. In this study, the gut microbiota at different developmental stages (larvae, pupae, and adults) of the honeybees Apis cerana in Hanoi, Vietnam, was assessed by sequencing the V3–V4 region in the 16S rRNA gene using the Illumina Miseq platform. The results indicated that the richness and diversity of the gut microbiota varied over the investigated stages of A. cenara. All three bee groups showed relative abundance at both phylum and family levels. In larvae, Firmicutes were the most predominant (81.55%); however, they decreased significantly along with the bee development (33.7% in pupae and 10.3% in adults) in favor of Proteobacteria. In the gut of adult bees, four of five core bacteria were found, including Gilliamella apicola group (34.01%) Bifidobacterium asteroides group (10.3%), Lactobacillus Firm-4 (2%), and Lactobacillus Firm-5 (1%). In contrast, pupae and larvae lacked almost all core bacteria except G. apicola (4.13%) in pupae and Lactobacillus Firm-5 (4.04%) in larvae. This is the first report on the gut microbiota community at different developmental stages of A. cerana in Vietnam and provides potential probiotic species for beekeeping.

Colibacillosis is an intestinal tract infection in poultry caused by Escherichia coli. It is one of the leading causes of mortality and results in significant economic losses for the poultry farming sector due to its high incidence rate. Recently, E. coli has been considered a predominant bacterial pathogen that is responsible for diarrhea and bloodstream infections in chickens and ducks in Vietnam. In this study, E. coli strains associated with diarrhea were isolated from chicken and duck feces and intestines collected from poultry farms in Hai Phong province using a Macconkey selective medium. The obtained isolates were initially identified by the MALDI-TOF MS method, screened for hemolytic activity, and finally identified by 16S rRNA gene sequencing. As a result, eight E. coli strains exhibiting hemolytic activity were identified. Among them, E. coli_5, E. coli_6, and E. coli_8 strains were clustered with E. coli O78:H51, whereas E. coli_3 was grouped with E. coli O78:H4; E. coli_4 and E. coli_7 were clusterd with E. coli O25b: H4; and E. coli_9 and E. coli_16 were grouped with E. coli O26:H11. Our results provide insights into the genetic diversity of E. coli strains associated with diarrhea in poultry farms in Hai Phong province. The isolated strains will be further characterized for the development of effective strategies to control colibacillosis in poultry.

Salmonella infections, or salmonellosis, represent a significant threat to poultry health and the global poultry industry, leading to considerable economic losses and serving as a major source of foodborne illnesses in humans and animals. Identifying the specific strains present in local poultry farms is crucial for implementing targeted interventions, including the development of effective biosecurity measures, vaccination strategies, and treatment protocols to mitigate outbreaks. This study focuses on isolating and characterizing Salmonella strains associated with diarrhea in chickens and ducks in Hai Duong province, Vietnam. The Salmonella strains were initially isolated using a culture-based method, followed by identification and characterization through Matrix-Assisted Laser Desorption Ionization/Time of Flight (MALDI-TOF), PCR amplification of the invA gene, and 16S rRNA gene sequencing. As a result, 18 Salmonella isolates were obtained, all of which contained the invA gene, indicating its potential significance in Salmonella pathogenesis. Analysis of the 16S rRNA gene sequences confirmed that all isolates belonged to the species Salmonella enterica, a well-known causative agent of intestinal diseases in humans and animals. Furthermore, phylogenetic analysis revealed that all 18 isolates grouped with Salmonella enterica subsp. enterica strains from China and Korea, suggesting a close relationship with strains circulating in the broader Southeast Asian region. This regional similarity may be attributed to the movement of poultry and poultry products, facilitating the cross-border spread of Salmonella. Our findings underscore the importance of implementing robust biosafety measures throughout the poultry production chain to control the spread of Salmonella, thereby enhancing both animal and food safety.

Honeybees harbor a distinct core microbiota that plays a crucial role in stress tolerance and disease resistance. However, infections can significantly alter the composition and diversity of their gut microbiota, impacting overall bee health. This study investigates the effects of Deformed Wing Virus (DWV) infection on the gut microbiota of Apis cerana honeybee. The samples were collected from six colonies in Hanoi, Vietnam, and analyzed using high-throughput sequencing of the 16S rRNA gene. Our results show that while the overall diversity of gut microbiota in DWV-infected and uninfected bees did not significantly differ, notable changes were observed in the relative abundances of specific bacterial taxa. In DWV-infected bees, the relative abundance of Proteobacteria significantly decreased, whereas Firmicutes increased compared to uninfected bees. At the genus level, a significant decrease in Gilliamella and an increase in Lactobacillus were observed in infected bees. Functional gene predictions indicated that pathways related to carbohydrate, fatty acid, and lipid metabolism, as well as the biosynthesis of cofactors, vitamins, and amino acids, were upregulated in DWV-infected bees. These findings highlight the impact of DWV infection on the gut microbiota of A. cerana and suggest potential avenues for using probiotics to restore gut microbial balance and improve honeybee health. This research provides a foundation for developing strategies to enhance the resilience of honeybee colonies against viral infections.

Beneficial bacteria are vital for maintaining honeybee health by outcompeting pathogenic microorganisms, boosting immunity, and enhancing resilience to diseases. Identifying the specific bacterial strains associated with honeybees enables the development of targeted probiotics that can improve the health of bees and humans. The present study describes the isolation and identification of bacterial strains from Apis cerana honeybees in Hanoi, Vietnam, utilizing a culture-based method, Matrix-Assisted Laser Desorption-Ionization Time of Flight Mass Spectrometry (MALDI-TOF) analysis, and 16S rRNA sequencing. MALDI-TOF analysis revealed several beneficial bacterial species, including Lactobacillus kunkeei, Lactobacillus plantarum, Pediococcus pentosaceus, Leuconostoc mesenteroides, Leuconostoc citreum, Bacillus subtilis, and Bacillus megaterium. Antimicrobial spectrum analysis showed that 16 out of the 23 identified isolates exhibited inhibitory effects against tested bacteria. Selected isolates with broad antimicrobial spectra, including L. kunkeei, L. plantarum, P. pentosaceus, L. mesenteroides, L. citreum, and B. subtilis, were further validated through 16S rRNA gene sequencing. The results confirmed the identity of these strains, emphasizing the probiotic potential of L. kunkeei, L. plantarum, L. mesenteroides, L. citreum, P. pentosaceus, and B. subtilis for honeybee health. Our findings provide valuable insights into the bacterial diversity and antimicrobial properties associated with honeybees, suggesting their use as probiotics in beekeeping and beyond.

Colibacillosis, caused by avian pathogenic Escherichia coli (APEC), represents a major threat to poultry production, leading to significant mortality and economic losses. This study aimed to characterize an APEC strain, HPVN24, isolated from diarrheic chickens at a farm in Hai Phong, Vietnam. The strain was investigated through phenotypic assays, antibiotic susceptibility profiling, and whole-genome sequencing using the Illumina platform. HPVN24 exhibited β-hemolytic activity and resistance to trimethoprim, ampicillin, and ciprofloxacin. Whole-genome analysis identified the strain as serotype O78:H9 and sequence type ST23, with a genome size of 5.05 Mb and a GC content of 50.57%. Genome annotation revealed a wide repertoire of genes involved in metabolism, secretion systems, virulence, and biofilm formation. Virulence-associated genes included those related to adhesion, iron acquisition, hemolysin production, and stress response. Analysis predicted multidrug resistance to 18 antibiotic classes, with particularly strong resistance to fluoroquinolones. Phylogenetic comparison demonstrated that HPVN24 clustered closely with O78:H9 strains isolated from poultry in other regions, suggesting potential transmission across populations. These findings indicate that HPVN24 is a multidrug-resistant and highly virulent APEC strain linked to colibacillosis outbreaks in Vietnam and highlight the need for ongoing surveillance, judicious antibiotic usage, and alternative strategies to ensure poultry health and food safety.