Investigation of biofilm producer in clinical isolates of klebsiella pneumoniae by phenotypic and pcr methods

Maral Bayati,1,* Babak asghari,2 Reza habibipour,3



The role of biofilm formation by bacteria has been proposedto be an important stage in the pathogenesis of klebsiellapneumoniae. this pathogen is the most important opportunistic pathogen agents of nosocomial infections such as pneumonia, urinary tract infections, invasive infections, and surgical site infections. the aim of this study was to investigate the biofilm producer strains isolated from different clinical isolates of k.pneumoniae.


230 clinical samples with bacterial infection were examined. the selective culture media and biochemical tests were used for identification of k.pneumoniae isolates. crystal violet assay and pcr were also used to characterize biofilm strains.


Of 230 bacterial isolates collected from different specimens, 100 isolates (43.47%) of k.pneumoniaewere identified by biochemical tests. of these, 58 isolates (58%) and 42 isolates (42%) were isolated from the male and female respectively. the phenotypic method was shown 2 isolates (2%) as a strong biofilm producer, 27 isolates (27%) as medium biofilm producers, 41 isolates (41%) as weak biofilm producers and 30 isolates (30%) as non-biofilm producers.also, the pcr were shown that 65 isolates (65%) had pgaa gene, among these isolates 2 isolates were strong biofilm producers (3.07%), 15 isolates were moderate biofilm producers (23.07 %), 27 isolates were weak biofilm producers (41.53%) and 21 isolates (32.3%) was non-biofilm producers.


The pgaa gene plays an important role in biofilm formation and is able to identify differentbiofilms in k.pneumoniae strains. it is also possible to identify bacteria with weak, moderate and strong biofilms.


Biofilms, virulence factor, klebsiella pneumonia, pgaa gene