For highly pathogenic bacteria, such as Bacillus anthracis, Yersina pestis, Burkholderia pseudomallei or Brucella spp., rapid and unambiguous detection is crucial for timely antibiotic therapy of infected patients. While polymerase chain reaction (PCR) is the gold standard for diagnostics of most infectious diseases, antibody-based assays that detect specific antigens of the pathogen are commonly used as confirmatory methods. However, these antibodies often feature insufficient specificity due to the high degree of relatedness of these pathogens to their non- or less pathogenic relatives. Receptor binding proteins (RBPs) of bacteriophages, which mediate recognition and binding to host bacteria, represent a promising alternative to antibodies. Here, we identified RBPs of a variety of phages specific for Bacillus anthracis, Yersina pestis, Burkholderia pseudomallei and Brucella spp. and utilized them to develop a set of novel tools for detection of these notorious pathogens. For this, recombinant RBPs were produced as fusions with different reporter proteins, such as fluorescent proteins or enzymes. In addition, RBPs were coupled to magnetic beads to serve as highly specific capture molecules for bacterial pathogen enrichment or isolation approaches.