The organism responsible for causing skin infections and toxic shock syndrome is Staphylococcus aureus. It is characterized by its grapelike clusters appearance in gram stain and production of the toxin that causes TSS.
The causative agent of skin infections and toxic shock syndrome among the listed options is Staphylococcus aureus. This bacterium is known for causing a variety of skin infections and can produce a superantigen called toxic shock syndrome toxin-1 (TSST-1), leading to toxic shock syndrome (TSS), particularly in women using tampons for extended periods. Staphylococcus aureus can be identified in the laboratory by its characteristic grapelike clusters in gram stain and is catalase-positive, which distinguishes it from Streptococcus species, another common cause of skin infections but is catalase-negative. Furthermore, Staphylococcus aureus is commonly found on healthy skin and nasal passages; however, pathogenic strains can lead to various other infections apart from skin infections.