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Klumpp, J.

Publications and source records attributed to Klumpp, J..

4 recordsLinked to original sources

A putative GtrB-like glycosyltransferase modulates cation-dependent BCP8-2 phage infection and cell surface structure in Bacillus cereus

Bacillus cereus is a foodborne pathogen of growing concern due to its persistence and antimicrobial resistance. To identify host determinants influencing susceptibility to phage BCP8-2, a mini-Tn10 transposon mutant library of B. cereus ATCC 14579 was constructed and screened for altered phage susceptibility. A mutant (BC2012) showing partial resistance carried an insertion in BC_RS27090 (previously BC_5432), encoding a putative GtrB-like bactoprenol glycosyltransferase. Complementation restored phage sensitivity, confirming its functional involvement. Adsorption and efficiency-of-plating assays revealed significantly reduced phage binding and infectivity in the mutant, particularly under cation-rich conditions. Microscopy showed altered surface morphology with thinner, smoother cell walls. These data indicate that gtrB affects surface properties essential for cation-dependent phage adsorption and infection and provide a foundation for future studies on the role of surface glycosylation and ionic interactions in Gram-positive phage biology. ImportancePathogenic Bacillus cereus is resilient across diverse environments and produces diverse toxins linked to foodborne outbreaks. Bacteriophages provide an effective strategy to control B. cereus; however, molecular targets of phage-host interaction are poorly understood, limiting the effective phage-based control. Current study addresses this gap by identifying a putative bactoprenol glycosyltransferase (GtrB), a vital factor in phage BCP8-2 susceptibility. Data obtained highlights partial reduction of phage infection in the gtrB mutant, demonstrating that precise glycosylation is essential for effective phage binding and entry. Our findings provide significant insights for advancing phage therapy, antibiotic resistance, and B. cereus biocontrol in food and clinical settings.

microbiology↗

A hybrid receptor binding protein enables phage F341 infection of Campylobacter by binding to flagella and lipooligosaccharides

Flagellotropic bacteriophages are interesting candidates as therapeutics against pathogenic bacteria dependent on flagellar motility for colonization and causing disease. Yet, phage resistance other than loss of motility has been scarcely studied. Here we developed a soft agar assay to study flagellotropic phage F341 resistance in motile Campylobacter jejuni. We found that phage adsorption was prevented by diverse genetic mutations in the lipooligosaccharides forming the secondary receptor of phage F341. Genome sequencing showed phage F341 belongs to the Fletchervirus genus otherwise comprising capsular-dependent C. jejuni phages. Interestingly, phage F341 encodes a hybrid receptor binding protein (RBP) predicted as a short tail fiber showing partial similarity to RBP1 encoded by capsular-dependent Fletchervirus, but with a receptor binding domain similar to tail fiber protein H of C. jejuni CJIE1 prophages. Thus, C. jejuni prophages may represent a genetic pool from where lytic Fletchervirus phages can acquire new traits like recognition of new receptors.

microbiology↗

Engineered reporter phages for rapid detection of Escherichia coli, Klebsiella spp., and Enterococcus spp. in urine

The rapid detection and species-level differentiation of bacterial pathogens facilitates antibiotic stewardship and improves disease management. Here, we develop a rapid bacteriophage-based diagnostic assay to detect the most prevalent pathogens causing urinary tract infections: Escherichia coli, Klebsiella spp., and Enterococcus spp. For each uropathogen, two virulent phages were genetically engineered to express a nanoluciferase reporter gene upon host infection. Using 206 patient urine samples, reporter phage-induced bioluminescence was quantified to identify bacteriuria and the assay was benchmarked against conventional urinalysis. Overall, E. coli, Klebsiella spp., and Enterococcus spp. were each detected with high sensitivity (68%, 78%, 85%), specificity (99%, 99%, 99%), and accuracy (90%, 94%, 96%) at a resolution of [>=]103 CFU/ml within 5 h. We further demonstrate how bioluminescence in urine can be used to predict phage antibacterial activity, demonstrating the future potential of reporter phages as companion diagnostics that guide patient-phage matching prior to therapeutic phage application.

microbiology↗

Genomic, proteomic, and phylogenetic analysis of spounaviruses indicates paraphyly of the order Caudovirales

It is almost a cliche that tailed bacteriophages of the order Caudovirales are the most abundant and diverse viruses in the world. Yet, their taxonomy still consists of a single order with just three families: Myoviridae, Siphoviridae, and Podoviridae. Thousands of newly discovered phage genomes have recently challenged this morphology-based classification, revealing that tailed bacteriophages are genomically even more diverse than once thought. Here, we evaluate a range of methods for bacteriophage taxonomy by using a particularly challenging group as an example, the Bacillus phage SPO1-related viruses of the myovirid subfamily Spounavirinae. Exhaustive phylogenetic and phylogenomic analyses indicate that the spounavirins are consistent with the taxonomic rank of family and should be divided into at least five subfamilies. This work is a case study for virus genomic taxonomy and the first step in an impending massive reorganization of the tailed bacteriophage taxonomy.

microbiology↗