title: Structural changes induced by a lytic bacteriophage make ciprofloxacin effective against older biofilm of Klebsiella pneumoniae.
abstract: Bacteria have evolved multiple mechanisms, such as biofilm formation, to thwart antibiotic action. Yet antibiotics remain the drug of choice against clinical infections. It has been documented that young biofilm of Klebsiella pneumoniae could be eradicated significantly by ciprofloxacin treatment alone. Since age of biofilm is a decisive factor in determining the outcome of antibiotic treatment, in the present study biofilm of K. pneumoniae, grown for extended periods was treated with ciprofloxacin and/or depolymerase producing lytic bacteriophage (KPO1K2). The reduction in bacterial numbers of older biofilm was greater after application of the two agents in combination as ciprofloxacin alone could not reduce bacterial biomass significantly in older biofilms (P > 0.05). Confocal microscopy suggested the induction of structural changes in the biofilm matrix and a decrease in micro-colony size after KPO1K2 treatment. The role of phage associated depolymerase was emphasized by the insignificant eradication of biofilm by a non-depolymerase producing bacteriophage that, however, eradicated the biofilm when applied concomitantly with purified depolymerase. These findings demonstrate that a lytic bacteriophage alone can eradicate older biofilms significantly and its action is primarily depolymerase mediated. However, application of phage and antibiotic in combination resulted in slightly increased biofilm eradication confirming the speculation that antibiotic efficacy can be augmented by bacteriophage.
authors: Department of Microbiology, Basic Medical Sciences (BMS) Block, Panjab University, Chandigarh, India.
authors: Vivek
authors: V
authors: Verma
authors: Kusum
authors: K
authors: Harjai
authors: Sanjay
authors: S
authors: Chhibber
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001435:Bacteriophages / Q000502:physiology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D002939:Ciprofloxacin / Q000494:pharmacology*; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000648:ultrastructure / Q000821:virology*; D008826:Microbial Sensitivity Tests; D018613:Microscopy, Confocal
chemical_list: D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin