Detection of biofilm formation and their correlation with Imipenem resistance among clinical isolates of Pseudomonas aeruginosa

Background: Pseudomonas aeruginosa causes life threatening infections especially hospital acquired infections or nosocomial infections. Biofilm producing
Pseudomonas aeruginosa isolates causes multidrug resistance pattern causing increase morbidity and mortality in a tertiary care hospital.
Aim’s and Objectives: 1. Isolation and identification of Pseudomonas aeruginosa; 2. To detect biofilm formation among Pseudomonas aeruginosa isolates;
3. To detect antibiotic resistance pattern among Pseudomonas aeruginosa isolates; 4. To study correlation between biofilm formation and Imipenem resistance
among Pseudomonas aeruginosa isolates
Materials and Methods: A prospective cross sectional study was conducted on all the clinical samples received from ICU (intensive care unit) at Department
of Microbiology, SIMS, Shimoga between January 2018 to December 2018. All the clinical samples were processed, identification and isolation of
Pseudomonas aeruginosa, detection of biofilm formation was done as per Standard microbiological methods. Antibiotic susceptibility test was done following
Kirby bauer disk diffusion test (DDT) as per CLSI 2017 guidelines.
Results: Out of 383 clinical samples received 294(76.76%) were positive cultures and 89(23.23%) were culture negative samples. Klebsiella species
106(36.05%) was most common organisms isolated followed by Staphylococcus aureus 70(23.80%), Pseudomonas spp. 66(22.44%), Escherichia coli
21(7.14%), Gram negative non fermenters (GNNF) 19(6.46%), Coagulase negative Staphylococcus aureus (CoNS) 12(4.08%). Out of 66 Pseudomonas
aeruginosa isolates 48(72.72%) were biofilm producers and 18(27.27%) were biofilm non producers. Among 48 biofilm positive Pseudomonas aeruginosa
isolates 17(54.28%) were biofilm positive by tube method, 31(74.28%) by Microtiterplate method (MTP). Out of 66 Pseudomonas aeruginosa isolates
47(71.21%), were Imipenem sensitive and 19(28.78%) were Imipenem resistant. All the 19(100%) Imipenem resistant Pseudomonas aeruginosa isolates were
biofilm producers.
Conclusion: Majority of Pseudomonas aeruginosa isolates were biofilm producers. Correlation between biofilm production and Imipenem resistance
contributes to morbidity and mortality and poor prognosis of patients.
Keywords: Biofilm, Pseudomonas aeruginosa, Imipenem resistance, ICU, Antimicrobial resistance