Microbiological spectrum and antimicrobial susceptibility patterns of various isolates from endotracheal tube aspirates in a tertiary care hospital, Hyderabad, Telangana

Abstract

Introduction: Endotracheal aspirates ( ET) are relatively simple ,easy to collect at the bedside and are used to evaluate the causes of lower respiratory tract infections in ventilated patients.Several studies reported multidrug resistant bacteria like Klebsiella, Pseudomonas and Acinetobacter spp,gram positive bacteria like S.aureus, S.pneumoniae ,Coagulase negative staphylococcus (CONS) and fungi like Candida spp in ET cultures. Even though Quantitation of the bacteria isolated from ET aspirates has been proposed as a criterion to distinguish colonization from true infection, only few studies have been done .The main aim of the present study was to evaluate the microbiological spectrum and antimicrobial susceptibility pattern of isolates from ET aspirates. Materials and Methods:ET aspirates were processed employing quantitative cultures. Growth of ?105cfu/ml was considered to be significant.Organism Identification and Antimicrobial susceptibility testing was performed according to standard guidelines. The gram negative isolates were further tested for ESBL/carbapenamase production and gram positive as methicillin sensitive / methicillin resistance. Results:Culture positivity was 67%. Acinetobacter spp was the most common isolate (46%) followed by Klebsiella spp (26%) and Pseudomonas spp (17%), E.coli (5%), S.aureus (2%), CONS (2%) and Candida (2%). Acinetobacter spp were extremely drug resistant. ESBL was produced by 38% and 64% of E. coli and Klebsiella spp. Out of the 15, 40% of the Pseudomonas spp and of 127 isolates, 63.7% of Acinetobacter spp were positive for carbapenamase production respectively .Out of the 7, 6 (86%) were methicillin resistant Staphylococcus aureus.5 (83%) of CONS (n=6) were methicillin resistant. Conclusion:We conclude that ET microscopic examination and quantitative cultures can be supportive in earlier prediction of ventilator-associated pneumonia. Keywords: Endotracheal aspirates, Microbiological spectrum, Quantitative cultures, Mult