Previously unknown regulatory role of extracellular RNA on bacterial directional migration.

Bacterial directional migration plays a significant role in bacterial adaptation. However, the regulation of this process, particularly in young biofilms, remains unclear. Here, we demonstrated the critical role of extracellular RNA as part of the Universal Receptive System in bacterial directional migration using a multidisciplinary approach, including bacterial culture, biochemistry, and genetics. We found that the destruction or inactivation of extracellular RNA with RNase or RNA-specific antibodies in the presence of the chemoattractant triggered the formation of bacterial "runner cells¼ in what we call a "panic state" capable of directional migration. These cells quickly migrated even on the surface of 1.5% agar and formed evolved colonies that were transcriptionally and biochemically different from the ancestral cells. We have also shown that cell-free DNA from blood plasma can act as a potent bacterial chemoattractant. Our data revealed a previously unknown role of bacterial extracellular RNA in the regulation of bacterial migration and have shown that its destruction or inhibition triggered the directional migration of developing and mature biofilms towards the chemoattractant.

Antifungal activity of a novel synthetic polymer M451 against phytopathogens.

Phytopathogenic fungi are the predominant causal agents of plant diseases. Available fungicides have substantial disadvantages, such as being insufficiently effective owing to intrinsic tolerance and the spread of antifungal resistance accumulating in plant tissues, posing a global threat to public health. Therefore, finding a new broad-spectrum fungicide is a challenge to protect plants. We studied the potency of a novel antimicrobial agent, M451, a 1,6-diaminohexane derivative, against different phytopathogenic fungi of the Ascomycota, Oomycota, and Basidiomycota phyla. M451 exhibited significant antifungal activity with EC50 values from 34-145 µg/mL. The minimal fungicidal concentration against Fusarium oxysporum ranged from 4 to 512 µg/mL depending on the exposure times of 5 min to 24 h. M451 has the highest activity and significantly lower exposure times compared to different polyene, azole, and phenylpyrrole antifungals. The conidial germination assay revealed that M451 induced 99 and 97.8% inhibition against F. oxysporum within 5 min of exposure to 5,000 and 500 µg/mL, respectively. Germ tube elongation, spore production, and spore germination were also significantly inhibited by M451 at concentrations of ≥50 µg/mL. Based on the broad spectrum of antifungal effects across different plant pathogens, M451 could be a new chemical fungicide for plant disease management.

Treatment of chronic relapsing urinary tract infection with antibiotics selected by AtbFinder.

We report the case of a 46-year-old patient who, after renal cancer surgery, developed a recurrent urinary tract infection that lasted for more than 2 years. Despite repeated antibiotic courses, including broad-spectrum drugs chosen using conventional antibiotic susceptibility testing, multiple reinfections followed. The patient was successfully treated once antibiotics were selected with AtbFinder. Unlike routine antimicrobial susceptibility methods, which select antibiotics effective only against a "lead bacterial pathogen," AtbFinder identifies antibiotics that target the mixture of bacteria at the infection site. This case demonstrates the ability of AtbFinder to successfully select antibiotics for the treatment of relapsing urinary tract infections.

Complete Genome Sequence of Kluyvera intestini sp. nov., Isolated from the Stomach of a Patient with Gastric Cancer.

We report here an update to the draft genome sequence of Kluyvera intestini sp. nov. strain GT-16, generated using MinION long-read sequencing technology. The complete genome sequence of the human-derived strain GT-16 measured 5,768,848 bp. An improved high-quality complete genome sequence provides insights into the mobility potential of resistance genes in this species.

Genomic characterization and assessment of the virulence and antibiotic resistance of the novel species Paenibacillus sp. strain VT-400, a potentially pathogenic bacterium in the oral cavity of patients with hematological malignancies.

BACKGROUND: Paenibacillus sp. strain VT-400, a novel spore-forming bacterium, was isolated from patients with hematological malignancies. METHODS: Paenibacillus sp. strain VT-400 was isolated from the saliva of four children with acute lymphoblastic leukemia. The genome was annotated using RAST and the NCBI Prokaryotic Genome Annotation Pipeline to characterize features of antibiotic resistance and virulence factors. Susceptibility to antibiotics was determined by the Kirby-Bauer disc diffusion method. We used a mouse model of pneumonia to study virulence in vivo. Mice were challenged with 7.5 log10-9.5 log10 CFU, and survival was monitored over 7 days. Bacterial load was measured in the lungs and spleen of surviving mice 48 h post-infection to reveal bacterial invasion and dissemination. RESULTS: Whole-genome sequencing revealed a large number of virulence factors such as hemolysin D and CD4+ T cell-stimulating antigen. Furthermore, the strain harbors numerous antibiotic resistance genes, including small multidrug resistance proteins, which have never been previously found in the Paenibacillus genus. We then compared the presence of antibiotic resistance genes against results from antibiotic susceptibility testing. Paenibacillus sp. strain VT-400 was found to be resistant to macrolides such as erythromycin and azithromycin, as well as to chloramphenicol and trimethoprim-sulphamethoxazole. Finally, the isolate caused mortality in mice infected with ≥8.5 log10 CFU. CONCLUSIONS: Based on our results and on the available literature, there is yet no strong evidence that shows Paenibacillus species as an opportunistic pathogen in immunocompromised patients. However, the presence of spore-forming bacteria with virulence and antibiotic resistance genes in such patients warrants special attention because infections caused by spore-forming bacteria are poorly treatable.

Complete Genome Sequence of Paenibacillus sp. Strain VT 400, Isolated from the Saliva of a Child with Acute Lymphoblastic Leukemia.

We report here the complete genome sequence of spore-forming Paenibacillus sp. strain VT 400, isolated from the saliva of a child with acute lymphoblastic leukemia. The genome consists of 6,986,122 bp, with a G+C content of 45.8%. It possesses 5,777 predicted protein-coding genes encoding multidrug resistance transporters, virulence factors, and resistance to chemotherapeutic drugs.

Complete Genome Sequence of the Streptococcus sp. Strain VT 162, Isolated from the Saliva of Pediatric Oncohematology Patients.

Streptococcus sp. strain VT 162 was isolated from the saliva of pediatric oncohematology patients. Its full genome is 2,045,418 bp. The availability of this genome will provide insights into the composition of microbial flora among pediatric oncohematology patients and the host interaction and pathogenicity of this species.