Induced antibiotic production against pathogenic Klebsiella pneumoniae by bacterial coculture.

Abstract

The world is running short of effective antibiotics due to rapid development of antibiotic resistance against currently available antibiotics. The frequency of new antibiotic discovery from conventional axenic cultures has decreased significantly. In current study, azithromycin and ciprofloxacin supplemented plates were used as selection filter for isolation of antibiotic-producing bacteria from Gomti river sediments. All bacterial isolates grown on antibiotic supplemented plates are antibiotic-resistant. Some of these, antibiotic-resistant isolates have ability to produce antibiotics of same scaffold for which they are resistant. Replica-plating technique have been successfully used to screen antibiotic producing among the antibiotic-resistant bacteria by modification of traditional resistance-guided approach. Seven antibiotic-producing bacterial isolates were isolated based on modified resistance-guided approach. All possible 21 two-membered combinations of these seven isolates were used to make bacterial consortia. Effectiveness of bacterial coculture has been evaluated based on antimicrobial potential of extracted antibiotics against pathogenic strains of Klebsiella pneumoniae by using well diffusion method. Significantly increased antibiotic production was observed in cocultures, namely RS2-RS6 and RS2-RS7. As azithromycin and ciprofloxacin were used as selection filter, the produced antibiotic will be either a macrolide or a fluoroquinolone. Highest antimicrobial activity was observed in RS2-RS6 coculture. Molecular characterization revealed that bacterial partners involved in RS2-RS6 coculture were strains of Bacillus cereus and K. pneumoniae which were shown significantly enhanced antibiotic production against pathogenic strains of Klebsiella pneumoniae. Presence of K. pneumoniae vbspurs6 in RS2-RS6 coculture indicates towards the possible use of pathogen related strains to induce antibiotic production against several other antibiotic resistance pathogens.