Bacteriophage-associated genes responsible for the widely divergent phenotypes of variants of Burkholderia pseudomallei strain MSHR5848

Colony morphotype variation in Burkholderia: implications for success of applications and therapeutics

The Burkholderia genus includes both environmental and pathogenic isolates known for their phenotypic plasticity and adaptability. Burkholderia spp. are intrinsically resistant to many antibiotics, often requiring prolonged therapies during infection. A key feature of Burkholderia spp. is colony morphotype variation (CMV), which allows for rapid adaptation to environmental changes and influences virulence, antibiotic resistance, and pathogenicity by impacting the expression of key virulence factors such as lipopolysaccharides, extracellular DNA, efflux pumps, and flagella. While alternative treatments, such as vaccines and phage therapies, hold promise, CMV has the potential to undermine their efficacy by modifying essential therapeutic targets. Despite its importance, the prevalence and underlying mechanisms of CMV remain poorly understood, leaving critical gaps in our knowledge that may hinder the development of sustainable solutions for managing Burkholderia infections. Addressing these gaps is crucial not only for improving infection management but also for enabling the safe reuse of Burkholderia in biotechnology, where their plant growth-promoting and bioremediation properties are highly valuable. Our goal is to raise awareness within the scientific community about the significance of CMV in Burkholderia, highlighting the urgent need to uncover the mechanisms driving CMV. A deeper understanding of CMV's role in virulence and resistance is essential to developing robust, long-term therapeutic strategies.

Induced Burkholderia prophages detected from the hemoculture: a biomarker for Burkholderia pseudomallei infection

Bacteriophages (phages), viruses that infect bacteria, are found in abundance not only in the environment but also in the human body. The use of phages for the diagnosis of melioidosis, a tropical infectious disease caused by Burkholderia pseudomallei, is emerging as a promising novel approach, but our understanding of conditions under which Burkholderia prophages can be induced remains limited. Here, we first demonstrated the isolation of Burkholderia phages from the hemocultures of melioidosis patients. The B. pseudomallei-positive hemoculture bottles were filtered to remove bacteria, and then phages were isolated and purified by spot and double agar overlay plaque assays. Forty blood samples (hemoculture-confirmed melioidosis) were tested, and phages were found in 30% of the samples. Transmission electron microscopy and genome analysis of the isolated phages, vB_HM387 and vB_HM795, showed that both phages are Myoviruses. These two phages were stable at a pH of 5-7 and temperatures of 25-37°C, suggesting their ability to survive in human blood. The genome sizes of vB_HM387 and vB_HM795 are 36.3 and 44.0 kb, respectively. A phylogenetic analysis indicated that vB_HM387 has homologs, but vB_HM795 is a novel Myovirus, suggesting the heterogeneity of Burkholderia phages in melioidosis patients. The key finding that Burkholderia phages could be isolated from the blood of melioidosis patients highlights the potential application of phage-based assays by detecting phages in blood as a pathogen-derived biomarker of infection.

Increase in cytotoxic lignans production after smut infection in sugar cane plants

Smut infection alters the transcription of dirigent proteins (DIR) by sugarcane plants. Here, we show that these alterations are associated to an elevated production of cytotoxic lignans. Smut-resistant sugarcane varieties display a fivefold increase in pinoresinol and also produce elevated amounts of secoisolariciresinol. Conversely, smut-sensitive varieties do not produce pinoresinol or secoisolariciresinol upon infection, synthesizing instead small amounts of matairesinol. Our data indicate that commercial pinoresinol and secoisolariciresinol seem to prevent smut teliospore germination and sporidia release from sprouted teliospores. Consistently, we observed abundant morphological alterations of sporidia incubated in the presence of these lignans. However, commercial lignans do not block the development of the pathogen in a definitive way. Additional experiments demonstrate that only the extracts from healthy or smut-exposed resistant plants inhibit sporidia growth in vitro, indicating that a specific mixture of lignans from resistant plants is necessary to constitute an effective defense mechanism.