OCA2 and allergic disease: Initially, exudation of the microbial metabolites and dynamic interaction among the microbial communities were detected with powerful SERS‐based nanosensor.[204] According to literature, one of the most common allergies in drug utilization was Penicillin allergy with a range of 8 to 25%.[205] One of the major causes of allergy was the Penicilloyl protein (P‐protein), which is derived after the rupture of β‐lactam ring from penicillin.