Isolation of Group A Streptococci with Reduced β-Lactam Susceptibility Harboring Amino Acid Substitutions in Penicillin-Binding Proteins in Japan.

Streptococcus pyogenes (group A Streptococcus [GAS]) has long been regarded as being susceptible to β-lactams. However, amino acid substitutions in penicillin-binding protein 2X (PBP2X) conferring reduced β-lactam susceptibility have been indicated since 2019 in the United States and Iceland. Here, we report the first isolation of Streptococcus pyogenes possessing the PBP2X substitution conferring reduced β-lactam susceptibility in Asia; however, the MICs were below the susceptible breakpoint of the CLSI.

Practical Agar-Based Disk Diffusion Tests Using Sulfamoyl Heteroarylcarboxylic Acids for Identification of Subclass B1 Metallo-β-Lactamase-Producing .

The worldwide distribution of carbapenemase-producing (CPE) is a serious public health concern as they exhibit carbapenem resistance, thus limiting the choice of antimicrobials for treating CPE infections. Combination treatment with a β-lactam and one of the newly approved β-lactamase inhibitors, such as avibactam, relebactam, or vaborbactam, provides a valuable tool to cope with CPE; however, these inhibitors are active only against serine-type carbapenemases and not against metallo-β-lactamases (MβLs). Therefore, it is important to readily differentiate carbapenemases produced by CPE by using simple and reliable methods in order to choose an appropriate treatment.