Biofilm production and multidrug resistant bacterial isolates in ventilator associated pneumonia

ABSTRACT

Context Ventilator-associated pneumonia is the second most common complication among all types of nosocomial infections. Mechanical ventilation predisposes to formation of a biofilm which worsens the prognosis because of increased multidrug resistant isolates implicated in formation of biofilm. Aim of the Study The study was conducted to find out the relationship between duration of mechanical ventilation, biofilm formation, and antibiotic resistance among VAPpathogens. Study Design and Methods: A descriptive analytical study of 150 clinically suspected VAPpatients was done. Patients were divided into Group I and II based on intubation duration for 1–5 days and more than 6 days, respectively. Endotracheal aspirate was collected from clinically diagnosed cases and processed as per standard microbiological techniques. Bacterial counts ? 106 CFU/ mLfor quantitative cultures were considered significant. Biofilm production was detected by tissue culture plate method. Multivariate analysis was done to find out the association of the various factors. Results: Klebsiella pneumoniae was the predominant bacteria isolated followed by Acinetobacterbaumannii. Among Gram negative bacteria 66.8% were ?-lactamase producers. In biofilm production by tissue culture method, Group I patients, 72.4% of the isolates showed either strong / moderate biofilm formation and in Group II patients, 92.3% of the isolates showed either strong / moderate biofilm formation. Multivariate analysis revealed that bacteria isolated from VAPoccurring after 5 days of mechanical ventilation among prior antibiotic-treated patients were resistant to all the antibiotics tested. Conclusion: Bacterial aetiology, prolonged intubation, biofilm formation, and drug resistance have ramification on outcome of VAP. Hence removal of ET tube in regular intervals should be considered with a proper choice of antimicrobial treatment or using ETtube coated with drugs/ biomaterials that discourage biofilm formation may be explored.