A novel papain inhibitory protein (SPI) from Streptomyces mobaraensis was studied to measure its inhibitory effect on bacterial cysteine protease activity (Staphylococcus aureus SspB) and culture supernatants (Porphyromonas gingivalis, Bacillus anthracis). Further, growth of Bacillus anthracis, Staphylococcus aureus, Pseudomonas aeruginosa, and Vibrio cholerae was completely inhibited by 10 μM SPI. At this concentration of SPI, no cytotoxicity was observed. We conclude that SPI inhibits bacterial virulence factors and has the potential to become a novel therapeutic treatment against a range of unrelated pathogenic bacteria. Copyright

dx.doi.org/10.1128/AAC.00129-13, hdl.handle.net/1765/61470
Antimicrobial Agents and Chemotherapy
This work was funded by the European Commission 7th Framework Programme; grant id fp7/241742 - An Integrated Tool-Kit for the Clinical Evaluation of Microbial Detection and Antibiotic Susceptibility Point-of-Care Testing Technologies (TEMPOTEST-QC)
Department of Medical Microbiology and Infectious Diseases

Zindel, S, Kaman, W.E, Fröls, S, Pfeifer, F, Peters, A, Hays, J.P, & Fuchsbauer, H.-L. (2013). The papain inhibitor (SPI) of Streptomyces mobaraensis inhibits bacterial cysteine proteases and is an antagonist of bacterial growth. Antimicrobial Agents and Chemotherapy, 57(7), 3388–3391. doi:10.1128/AAC.00129-13