Screening and isolation of antibiotic-producing microbes from sea cucumber and testing their broad-spectrum activity

Background: Multidrug resistance of microbes forced the scientific community to search for newer antibiotics to treat infectious diseases. The literature review revealed that fishermen used the sea cucumber species for healing the wounds. Aim: As sea cucumber is rich in microbial flora, an attempt has been made to screen the antibiotic-producing microbes from them. Materials and Methods: Five sea cucumbers were collected from Kanyakumari district, Tamil Nadu, and dissected. The intestinal fluids and coelomic fluids were collected and named as IF and cystic fibrosis CF, respectively. The crowded plate method was followed to screen the antibiotic-producing microbes. As part of the primary screening, the perpendicular streak method was carried out to reveal the broad-spectrum potential of isolates. The selected isolates which showed the broad spectrum of activity were grown in soyabean casein broth media to produce the antibiotic principles. After the separation of cells from the fermented media, the agar well method was carried out against test organisms to reveal the broad spectrum of activity of the fermented broths. Results: The present investigation resulted in the isolation of 35 isolates with antibiotic-producing ability in crowded plate method. Out of 35 isolates, only 9 of them passed the primary screening. The secondary screening revealed that the fermented broths of three isolates (named IF32, IF52, and CF42) were found to have a better broad spectrum of activity.