Screening of Rare Actinobacteria for Antiquorum Sensing Properties against Proteus mirabilis and Serratia marcescens

Abstract

Objectives: Multidrug-Resistant (MDR) bacteria are a global health threat, driving interest in alternative, non-antibiotic therapies. Quorum-Sensing Inhibition (QSI) disrupts bacterial communication, reducing virulence and antibiotic resistance. The current study is focused on isolating new actinobacteria from various biodiverse regions of Maharashtra, India, and their screening for antimicrobial activity against Proteus mirabilis, the most prevalent causative agent of urinary tract infections, and anti-quorum-sensing activity against Serratia marcescens, primarily known for hospital-acquired infections.Materials and Methods: Actinobacteria are prolific producers of bioactive compounds and are emerging as promising sources of QSI agents. The focus was on isolating new actinobacteria from various biodiverse regions of Maharashtra, India.Results: Successful isolation of 66 actinobacteria was done. Of these, 25 isolates showed potent inhibition against Bacillus subtilis, 11 isolates showed activity against Proteus mirabilis, and 24 isolates exhibited activity against Serratia marcescens. The organic extracts of 18 isolates demonstrated significant inhibition of swarming behaviour compared to the control. The study reveals a few rare genera of actinobacteria, like Amycolotopsis tucumanensis, Amycolotopsis orientalis, Microbacterium barkeri, Yuhushiella, and Nocardia.Conclusion: Our findings highlight that the Bhushi Dam, Venna Lake, and Melghat forest of Maharashtra are underexplored and unique ecological habitats harboring previously uncharacterized actinomycetes with significant potential for novel antibiotic discovery.

Keywords: 16S rRNA; Actinobacteria; Autoinducers; Multi-drug resistance; Quorum sensing; Quorum-sensing inhibitors