BACKGROUND: With the widespread use of antibiotics, more attention has been paid to their side effects. We paid extra attention to the impact of antibiotics on children\'s bodies. Therefore, we analyzed the characteristic changes in the gut microbiota of children after antibiotic treatment to explore the pathogenesis of antibiotic-associated diseases in more depth and to provide a basis for diagnosis and treatment.
METHODS: We recruited 28 children with bronchopneumonia in the western district of Zhuhai, China, and divided them into three treatment groups based on antibiotic type. We took stool samples from children before and 3-5 days after antibiotic treatment. 16S rRNA gene sequencing was used to analyze the effects of antibiotic therapy on the gut microbiota of children. Continuous nonparametric data are represented as median values and analyzed using the Wilcoxon rank-sum test.
RESULTS: While alpha diversity analysis found no significant changes in the mean abundance of the gut microbiota of children after a short course of antibiotic treatment, beta diversity analysis demonstrated significant changes in the composition and diversity of the gut microbiota of children even after a short course of antibiotic therapy. We also found that meloxicillin sulbactam can inhibit the growth of Proteobacteria, Bacteroidetes, and Verrucomicrobia, ceftriaxone inhibits Verrucomicrobia and Bacteroides, and azithromycin inhibits Fusobacteria, Actinobacteria, Proteobacteria, and Verrucomicrobia. We further performed a comparative analysis at the genus level and found significantly different clusters in each group. Finally, we found that azithromycin had the greatest effect on the metabolic function of intestinal microbiota, followed by ceftriaxone, and no significant change in the metabolic process of intestinal microbiota after meloxicillin sulbactam treatment.
CONCLUSIONS: Antibiotic treatment significantly affects the diversity of intestinal microbiota in children, even after a short course of antibiotic treatment. Different classes of antibiotics affect diverse microbiota primarily, leading to varying alterations in metabolic function. Meanwhile, we identified a series of intestinal microbiota that differed significantly after antibiotic treatment. These groups of microbiota could be used as biomarkers to provide an additional basis for diagnosing and treating antibiotic-associated diseases.

UNASSIGNED: Klebsiella pneumoniae is a major cause of hospital-acquired infections (HAIs), primarily spread through environmental contamination in hospitals. The effectiveness of current chemical disinfectants is waning due to emerging resistance, which poses environmental hazards and fosters new resistance in pathogens. Developing environmentally friendly and effective disinfectants against multidrug-resistant organisms is increasingly important.
UNASSIGNED: This study developed a bacteriophage cocktail targeting two common carbapenem-resistant Klebsiella pneumoniae (CRKP) strains, ST11 KL47 and ST11 KL64. The cocktail was used as an adjunctive disinfectant in a hospital\'s respiratory intensive care unit (RICU) via ultrasonic nebulization. Digital PCR was used to quantify CRKP levels post-intervention. The microbial community composition was analyzed via 16S rRNA sequencing to assess the intervention\'s impact on overall diversity.
UNASSIGNED: The phage cocktail significantly reduced CRKP levels within the first 24 hours post-treatment. While a slight increase in pathogen levels was observed after 24 hours, they remained significantly lower than those treated with conventional disinfectants. 16S rRNA sequencing showed a decrease in the target pathogens\' relative abundance, while overall species diversity remained stable, confirming that phages selectively target CRKP without disrupting ecological balance.
UNASSIGNED: The findings highlight the efficacy and safety of phage-based biocleaners as a sustainable alternative to conventional disinfectants. Phages selectively reduce multidrug-resistant pathogens while preserving microbial diversity, making them a promising tool for infection control.

Streptomyces species are experts in the production of bioactive secondary metabolites; however, their taxonomy has fallen victim of the tremendous interest shown by the scientific community, evident in the discovery of numerous synonymous in public repositories. Based on genomic data from NCBI Datasets and nomenclature from the LPSN database, we compiled a dataset of 600 Streptomyces species along with their annotations and metadata. To pinpoint the most suitable taxonomic classification method, we conducted a comprehensive assessment comparing multiple methodologies, including analysis of 16S rRNA, individual housekeeping genes, multilocus sequence analysis (MLSA), and Fast Average Nucleotide Identity (FastANI) on a subset of 409 species with complete data. Due to insufficient resolution of 16S rRNA and inconsistency observed in individual housekeeping genes, we performed a more in-depth analysis, comparing only FastANI and MLSA, which expanded our dataset to include 502 species. With FastANI validated as the preferred method, we conducted pairwise analysis on the entire dataset identifying 59 non-unique species among the 600, and subsequently refined the dataset to 541 unique species. Additionally, we collected data on 724 uncharacterized Streptomyces strains to investigate the uniqueness potential of the unannotated fraction of the Streptomyces genus. Utilizing FastANI, 289 strains could be successfully classified into one of the 541 Streptomyces species. KEY POINTS: • Evaluation of taxonomic classification methods for Streptomyces species. • Whole genome analysis, specifically FastANI, has been chosen as preferred method. • Various reclassifications are proposed within the Streptomyces genus.

UNASSIGNED: Kurixaluslenquanensis Yu, Wang, Hou, Rao and Yang, 2017 was originally described, based on 14 adult male specimens from Lengquan Village, Mengzi, Yunnan, China. So far, this species is known only from south-eastern Yunnan and information on females of this species is not available. During the field surveys in 2023, two Kurixalus specimens (one female and one male) were collected from central eastern Yunnan (Shilin, Kunming, Yunnan, China). These two specimens were confirmed to be K.lenquanensis by molecular phylogenetic analyses, based on 16S rRNA sequences.
UNASSIGNED: A female specimen of K.lenquanensis is described for the first time and morphological variation amongst populations of this species is provided. The diagnosis and distribution of this species are updated.

While the gut microbiome has been intensively investigated for more than twenty years already, its role in various disorders remains to be unraveled. At the same time, questions about what changes in the gut microbiota can be considered as normal or pathological and whether communities are able to recover after exposure to negative factors (diseases, medications, environmental factors) are still unclear. Here, we describe changes in the gut microbiota composition and the content of short-chain fatty acids in adult healthy volunteers (n = 15) over a 24 month-period. Intraindividual variability in gut microbial composition was 40%, whereas the short chain fatty acids profile remained relatively stable (2-year variability 20%, inter-individual 26%). The changes tend to accumulate over time. Nevertheless, both short-term and long-term changes in the gut microbiome composition were significantly smaller within individuals than interindividual differences (two-year interindividual variability was 75%). Seasonal changes in gut microbiota were found more often in autumn and spring involving the content of minor representatives (less than 1.5% of the community in average) in the phyla Actinobacteriota, Firmicutes and Proteobacteria.

Osmia excavata is an excellent pollinator in nature and plays a vital role in the conservation of agro-ecosystems and food security. Given the important role of the gut bacterial community in host health and regulation of host growth and development, using 16S rRNA gene sequencing data, the present study explored the composition of the gut bacterial community and its diversity at different life stages (eggs, young larvae, old larvae, young pupae, old pupae, and 1-day-old adults in cocoons) of the solitary bee Osmia excavata. The results showed that the core phyla in the gut of O. excavata at different life stages were Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteriota, and the core genera were Sodalis, Tyzzerella, and Ralstonia. The highest intestinal bacterial diversity was found in the Egg period, and the lowest bacterial alpha diversity was found in the 1-day-old Adult period; the bacterial diversity of O. excavata showed a process of decreasing, as it was growing from the Egg period to the 1-day-old Adult period. Our study found that O. excavata undergoes a significant change in the structure of the gut flora when it grows from the young pupae to old pupae stage, a period of growth that coincides with the process of cocooning and isolation from the external environment after food depletion. This suggests that food and environmental factors are key contributors to the structure of the bacterial community in the gut of solitary bees.

Apical periodontitis is an inflammatory disease triggered by oral pathogens invading necrotic root canals. The aim of this study was to evaluate the coronal and root canal bacterial community profiles in primary endodontic infections with different periapical (PAI) indices in comparison to oral mucosa controls. A total of 31 patients with primary apical periodontitis, 14 with PAI-1 and 17 with PAI-3 were recruited. Microbial specimens from mucosa (control samples) and endodontic necrotic tissues were collected in each patient. Microbiota composition was studied through 16S ribosomal RNA gene amplicon sequencing analysis. Overall, 2953 taxa from 168 different genera of 451 various microbial species were retrieved in the controls and PAI-1 and PAI-3 groups. Firmicutes is the predominant phylum in the oral controls (34.5%) and PAI-1 (44.4%) groups, while Bacteroidetes is predominant in PAI-3 (38.6%). The Proteobacteria (21.5%) and Fusobacteria (12.5%) relative abundance is higher in oral controls while that of Synergistetes is higher in the PAI-1 (3.5%) and PAI-3 (2.5%) groups, being almost absent in controls (less than 0.1%). Most of the increased bacterial species found in the PAI groups were strict anaerobes. A diminished microbial diversity was found in apical periodontitis with higher PAI. These samples were also characterized by an increase in bacteria belonging to phyla and genera with an increased anaerobic character.

Diet-induced obesity is a global phenomenon that affects the population worldwide with manifestations at both the phenotypic and genotypic levels. Cognitive function decline is a major global health challenge. The relation between obesity and cognitive function is a debatable issue. The main goal of the current research was to study the implications of obesity on cognitive function and gut microbiota diversity and its impact on plasma and brain metabolic parameters in rats. Obesity was induced in rats by feeding on a high-fat (HF) or a high-fat/high-sucrose (HFHS) diet. The results reveal that both the HF (0.683) and HFHS (0.688) diets were effective as obesity inducers, which was confirmed by a significant increase in the body mass index (BMI). Both diet groups showed dyslipidemia and elevation of oxidative stress, insulin resistance (IR), and inflammatory markers with alterations in liver and kidney functions. Obesity led to a reduction in cognitive function through a reduction in short-term memory by 23.8% and 30.7% in the rats fed HF and HFHS diets, respectively, and learning capacity and visuo-spatial memory reduced by 8.9 and 9.7 s in the rats fed an HF or HFHS diet, respectively. Bacteroidetes, Firmicutes, Proteobacteria, Fusobacteria, and Spirochaetes phyla were detected. The Firmicutes/Bacteroidetes ratio (F/B) significantly decreased in the HF group, while it increased in the HFHS group compared to the normal control. The two species, Bacteroides acidifaciens and Bacteroides ovatus, which are associated with IR, were drastically compromised by the high-fat/high-sucrose diet. Some species that have been linked to reduced inflammation showed a sharp decrease in the HFHS group, while Prevotella copri, which is linked to carbohydrate metabolism, was highly enriched. In conclusion: Obesity led to cognitive impairment through changes in short-term and visuo-spatial memory. A metagenomic analysis revealed alterations in the abundance of some microbial taxa associated with obesity, inflammation, and insulin resistance in the HF and HFHS groups.

Phytogenic blends (PBs) consist of various bioactive plant-derived compounds that are used as growth promoters for farm animals. Feed additives based on PBs have beneficial effects on farm animals\' production performance, health, and overall well-being, as well as positive modulating effects on gut microbiota. In this study, we used a validated in vitro cecal chicken alimentary tract model (CALIMERO-2) to evaluate the effects of a PB (a mix of components found in rosemary, cinnamon, curcuma, oregano oil, and red pepper), alone or in combination with casein (control), on poultry cecal microbiota. Supplementation with the PB significantly increased the abundance of bacteria associated with energy metabolism (Monoglobus) and growth performance in poultry (Lachnospiraceae UCG-010). The PB also decreased the abundance of opportunistic pathogens (Escherichia-Shigella) and, most importantly, did not promote other opportunistic pathogens, which indicates the safety of this blend for poultry. In conclusion, the results of this study show promising perspectives on using PBs as feed additives for poultry, although further in vivo studies need to prove these data.

Parasitoids have the potential to alter the gut microbiota of their host insects post-parasitization, thereby influencing the host\'s physiological functions and creating a more favorable environment for the survival of the parasitoid\'s progeny. Cotesia ruficrus is a native enemy of the important invasive fall armyworm (FAW) pest, Spodoptera frugiperda, in China, exhibiting significant pest control capabilities. To investigate the impact of C. ruficrus on the gut bacteria of FAW caterpillars following parasitism, we used 16S rRNA sequencing technology to analyze the diversity and richness of gut bacteria in both long-term laboratory and short-term laboratory FAW caterpillars. The results revealed Enterococcus as the predominant bacteria across all treatments, while no significant differences were observed in the diversity and richness of gut bacteria between non-parasitized and parasitized long-term laboratory FAW caterpillars. Similarly, while the diversity of gut bacteria in non-parasitized and parasitized short-term laboratory FAWs showed no significant variance, a marked discrepancy in richness was noted. Moreover, the richness of gut bacteria in short-term laboratory FAW caterpillars surpassed that of their long-term laboratory counterparts. In addition, it was found that Corynebacterium existed only in the intestinal tract of FAW caterpillars that were parasitized by C. ruficrus. These results substantiate that C. ruficrus parasitization can alter the gut microbiota of FAW caterpillars, providing valuable insights into the interplay between gut microbiota and the dynamics of parasitoid-host interactions.