BIOFILM PRODUCTION AND ANTIMICROBIAL RESISTANCE IN VENTILATOR ASSOCIATED PNEUMONIA (VAP) PATHOGENS OF ICUs OF TERTIARY CARE CENTER OF CENTRAL GUJARAT.
Authors: Patel Chirag , Shah M B , Singh Suman , Modi Chirag , Thakor Ankit 
Published: June 2021

Background:  In critical care units, Ventilator-associated pneumonia (VAP) is a common device-associated infection in mechanically ventilated patients. Problem gets worst of associated with biofilm producing organism with higher antimicrobial resistance. The current study was carried out to observe the pattern of antimicrobial resistance, biofilm forming capacity of isolates causing Ventilator-associated pneumonia and other risk factors associated with VAP patients in intensive care units of Shree Krishna Hospital, Karamsad.

Methodology:  97 total tracheal aspirate culture isolates recovered from 83 mechanically ventilated patients diagnosed to be suffering from VAP as per NHSN definition, admitted in various ICUs of Shree Krishna Hospital, Karamsad during the study duration were included in the study. Relevant clinical history of the patients and other details taken for various patient variable factors like age, gender, co-morbid conditions, indoor days, ventilator days, final patient outcome and other lab based investigations done as indicator of active pneumonia or sepsis from the electronic hospital database available on hospital information system. The tracheal aspirate culture isolates were then tested for antimicrobial susceptibility testing by Vitek2compact and in-vitro biofilm production assay using microtitre plate method. Objective of the present study was to determine the incidence of antimicrobial resistance, biofilm forming capacity of VAP pathogens, to determine risk factors associated and final outcome in VAP patients infected with biofilm forming pathogens. Chi-square test was used to check the relation between the categorical variables while t test was applied in case of continuous variables. A p value less than 0.05 was considered as statistically significant.

Results:  Out of total 83 patients of VAP, 97 isolates recovered in tracheal aspirate culture. Out of total 83 patients, 42 patients (49 isolates) were found Biofilm producer (BFP) and 41 patients (48 isolates) were found Biofilm non-producer (BFNP). Out of 97 culture total isolates, the most common organisms grew were Klebsiella pneumoniae (29 isolates), Acinetobacter baumani (28 isolates) and Pseudomonas aeruginosa (19 isolates) apart from them lesser number of isolates of Staphylococcus aureus (6), Escherichia coli (5), Pantoea spp. (2), Serretia marcescens (2), Pseudomonas putida (1), Sphingomonas paucimobilis (1), Stenotrophomonas maltophila (1), Enterococcus faecium (1), Candida famata (1) and Candida tropicalis (1). The antimicrobial resistance was compared in three major pathogen between BFP and BFNP isolates, i.e. Klebsiella pneumoniae, Acinetobacter baumani and Pseudomonas aeruginosa, which was found to be statistically insignificant. Mortality was recorded higher in BFP patients (16.67%) compared to BFNP patients (7.3%) of VAP, but statistically it was not found to be significant (p value > 0.05).

Conclusions:  Incidence of BFP and BFNP associated VAP seen 50.51% and 49.49% respectively out of total 97 isolates. Biofilm forming pathogen causing VAP may not influence the outcome of the patient but, biofilm producer pathogens continue to be associated with pathogens causing VAP in significant amount of total cases. Typical hospital acquired strains like Klebsiella pneumoniae, Acinetobacter baumani and Pseudomonas aeruginosa is recorded frequently compared to other pathogens.

Key words: Intensive Care Unit, anti-microbial resistance, VAP, Bio film, Health care associated infection, Indwelling device associated infection.