The objective of the study is to evaluate the effect of methanol extracts of Morinda tinctoria fruits on biofilm formation of clinically important AmpC β-lactamases producing K. pneumoniae. K. pneumoniae clinical isolates were screened for the production of AmpC β-lactamases by AmpC disc test. Biofilm inhibition studies were conducted on 24-well polystyrene well plates. Four uropathogenic isolates of K. pneumoniae were shown to produce AmpC β-lactamases. The methanol extracts at Biofilm inhibitory concentration (BIC - 0.06 mg ml-1) of M. tinctoria fruits (immature, midmature and mature) were revealed to inhibit the biofilms formed by K. pneumoniae. The finding of the present study describes M. tinctoria fruit extracts as a promising source for biofilm inhibition in K. pneumoniae which have acquired resistance to third and fourth generation cephalosporins. This is the first report on biofilm inhibition of AmpC producing K. pneumoniae using fruit extracts of M. tinctoria at different maturity stages.
