Correlation between biofilm formation and carbapenem resistance among clinical isolates of Klebsiella pneumoniae

Abstract

Background : Klebsiella pneumoniae is a Gram-negative entericbacterium that causes nosocomial infections; this bacterium hassurvived from harsh condition using biofilm formation in hospitalequipment and cause severe infection. In the other hand, theemergence and extension of carbapenem resistance burden amongK. pneumonia producing biofilm is the current concern of publichealth services. There are controversial findings about this subject.The aim of this study was to evaluate the correlation betweenbiofilm formation and resistance to carbapenem among clinicalisolates of K. pneumoniae.Methods: A total of 160 K. pneumoniae isolates were collectedfrom various infections of hospitalized patients. The Carba NP testand molecular methods were used for detection of carbapenemresistance isolates of K. pneumonia. Subsequently, the ability forbiofilm production was performed from all isolates. Finally,Correlation of biofilm formation among carbapenem resistantisolates was calculated using χ2 and Fisher’s exact tests.Results: Among K. pneumoniae isolates 42.5% havecarbapenemase activity by Carba NP test, while carbapenemasegenes were detected in 35.6% of isolates in amplification assay.Moreover, there are 52.5% (n= 84) of all isolates were formed astrong biofilm, while 38.1% (n= 61) and 9.3% (n= 15) of isolateswere middle and weak biofilm producer, respectively. Amongcarbapenem resistant cases (n= 68), there are 77.9% (n= 53) and22% (n= 15) of isolates were reported as strong and middle biofilmproducer, respectively. We see a significant correlation was seenbetween biofilm formation ability and carbapenem resistantisolates (p-value < 0.00001).Conclusion: The increase of carbapenem resistance burden inbiofilm producing isolates of K. pneumoniae is considered asserious alert and the basic measures to combat this phenomenon isimperative.