Proteolytic Profiling of Streptococcal Pyrogenic Exotoxin B (SpeB) by Complementary HPLC-MS Approaches

Streptococcal pyrogenic exotoxin B (SpeB) is a cysteine protease expressed during group A streptococcal infection that represents a major virulence factor. Although subject to several studies, its role during infection is still under debate, and its proteolytic properties remain insufficiently characterized. Here, we revisited this protease through a set of complementary approaches relying on state of-the-art HPLC-MS methods. After conceiving an efficient protocol to recombinantly express SpeB, the zymogen of the protease and its activation were characterized. Employing proteome-derived peptide libraries, a strong preference for hydrophobic and aromatic residues at P2 alongside negatively charged amino acids at P3′ to P6′ was revealed. To identify relevant in vivo substrates, native proteins were obtained from monocytic secretome and plasma to assess their cleavage under physiological conditions. Besides corroborating our findings concerning specificity, more than 200 cleaved proteins were identified, including proteins of the extracellular matrix, proteins of the immune system, and proteins involved in inflammation. Finally, the cleavage of IgG subclasses was studied in detail. This study precisely depicts the proteolytic properties of SpeB and provides a library of potential host substrates, including their exact cleavage positions, as a valuable source for further research to unravel the role of SpeB during streptococcal infection.

Tonsillitis-Related Arthritis: Advanced Understandings of Tonsillitis and Sterile Inflammatory Arthritis

A 49-year-old man developed acute aseptic arthritis of the nonmigratory and asymmetrical type in his knee, ankle, and bilateral metatarsal joints 13 days after treatment with antibiotics for acute tonsillitis. He was diagnosed with tonsillitis-related arthritis after other rheumatic diseases were ruled out. Treatment with salazosulfapyridine, methotrexate, and methylprednisolone for 3 months did not completely improve. Then, tonsillectomy was undertaken and arthritis rapidly improved. Finegoldia magna (previously Peptostreptococcus magnus) was cultured from the microabscesses of the resected tonsils. After outpatient follow-up, the patient did not experience a relapse of arthritis for more than 2.7 years without any treatment. Poststreptococcal reactive arthritis (PSRA) is well described. However, up to 40% of patients with tonsillitis-related arthritis did not demonstrate evidence of streptococcal infection. It is noted that tonsillectomy is necessary to remove the tonsillar microabscesses and eradicate bacterial infection of the tonsils, especially for patients with a prolonged and/or recurrent course of PSRA and/or tonsillitis-related arthritis.

An unusual presentation of familial Mediterranean fever with co-existing polyarteritis nodosa and acute post-streptococcal glomerulonephritis

The homozygous M694V mutation in the MEFV gene may cause an augmented response to the streptococcal infection that plays a role in the development of APSGN and PAN. Both clinical manifestations may occur simultaneously after streptococcal infection in a child who is previously healthy but carries a MEFV mutation.

Efficacy of attenuated bacteria vaccine against streptococcal infection in larvae tilapia (Oreochromis niloticus)

One of the common diseases found in tilapia is a streptococcal disease caused by the Streptococcus agalactiae bacteria. Treatment of this disease is generally done by using antibiotics. The use of antibiotics in controlling disease in fish can create resistant bacterial strains with certain doses. The use of vaccines is one of the alternative control methods in fish defence against infections. The purpose of this study was to analyze the efficacy of vaccination on seeds through immersion using attenuated active bacteria to increase immunity at the beginning of the spread of streptococcosis disease. The vaccine used was obtained from attenuated Streptococcus agalactiae bacteria through repeated passage ten times. Vaccination was carried out through oral vaccine. Challenge tests were carried out on days 7, 14, and 21 days after vaccination on tilapia larvae by immersion. The result indicated that vaccination using attenuated bacteria could increase lysozyme activity at each observation time compared to control. The mortality of post-challenged larvae on days 7, 14 and 21 post-vaccination was lower than that of unvaccinated seed. The percentage of RPS values up to the 14th day of observation has increased and tends to decrease on the 21st day.