Klebsiella pneumoniae is a nosocomial pathogen in outbreaks of hospital infections. It is one of the major factors for morbidity and mortality in hospitalized patients especially those infected with colistin-resistant pathogens. Many plant essential oils have antimicrobial activities and have been investigated as natural sources to combat multiple antibiotic resistances. Moreover; recent advances in phytonanotechnology have created exciting opportunities for the management of many infections.
This study aims at investigating the antimicrobial and antibiofilm effect of rosemary and ginger essential oil-based nano-sized formulations on colistin-resistant K. pneumonia clinical isolates.
Isolation and identification of 30 K. pneumonia isolates from different human samples was done followed by antibiotic susceptibility testing and detection of biofilm gene (mrkD). Examination of the activity of the tested essential oils and their chitosan nanoparticle formulations against the selected isolates was made by determination of their MICs using broth microdilution method followed by biofilm inhibition test and quantitative real-time PCR for the expression of mrkD gene in the presence of the oils and nanoparticles formulations compared to untreated bacterial isolates.
Our results showed that the minimum inhibitory concentrations of rosemary and ginger oils were found to be 1250 μg/ml, nanostructured lipid carrier-rosemary oil and nanostructured lipid carrier-ginger oil were 625 μg/ml and rosemary oil loaded chitosan nanoparticles and ginger oil loaded chitosan nanoparticles were 156 μg/ml. Results also revealed complete (100%) inhibition for mrkD gene expression when compared to untreated K. pneumonia.
We can conclude that oil loaded chitosan nanoparticles show a high antimicrobial and antibiofilm activity.