Bacteriological profile and antimicrobial sensitivity pattern of endotracheal tube aspirates of patients admitted in ICU

Abstract

Background: Ventilator-associated pneumonia (VAP) in critically ill patients are associated with high morbidity and mortality as they are at a high risk of acquiring respiratory infections, due to complex interplay between the endotracheal tube, host immunity and virulence of invading bacteria. Several studies reported multidrug-resistant bacteria like Acinetobacter spp., Pseudomonas spp., Gram-positive bacteria like S. aureus. For prompt initiation of empirical antimicrobial treatment, knowledge of local antimicrobial resistance patterns is essential. Aims: To study antimicrobial sensitivity among organisms isolated from endotracheal aspirates of patients with VAP and examine their various resistance pattern and look for biofilm production. Materials and Methods: ET aspirates were taken from 140 patients who were mechanically ventilated for various reasons in ICU of our hospital and were subjected to Gram stain and semiquantitative cultures. Organism identification and antimicrobial susceptibility testing were performed according to standard guidelines. Various resistance patterns and biofilm production on Congo Red Agar were observed. Results: Out of 140 ET aspirates processed, 120 samples (85.7%) were culture positive; most common isolate being Acinetobacter spp. (45.8%), followed by Pseudomonas spp. and Klebsiella spp. (16.6% each), and Gram-positive isolate Staphylococcus aureus (12.5%). All Staphylococcus aureus were sensitive to linezolid and resistant to cefoxitin (MRSA). Most of the Gram-negative isolates were sensitive to imipenem. ESBL resistance was seen in 25% of Klebsiella spp. and Amp C resistance was seen in 27% of Acinetobacter spp. Biofilm was produced in 62.5% of the isolates. Mortality was maximum in patients whose ET aspirates showed biofilm production. Conclusion: A local antibiogram pattern for each hospital, based on bacteriological profile and susceptibilities, is essential, to initiate empiric therapy and help in framing the appropriate institutional antibiotic policy.