Analysing the usefulness of Gram's stain of sputum and its culture in patients suspected of Lower respiratory tract infections -- Study from tertiary care centre.

Dr. Aparna Aparajita; Dr. Manoj Kumar

Volume : IX, Issue : VIII, August - 2020

Analysing the usefulness of Gram's stain of sputum and its culture in patients suspected of Lower respiratory tract infections -- Study from tertiary care centre.

Dr. Aparna Aparajita, Dr. Manoj Kumar

Abstract :

Introduction: The use of Gram stained smears to assess the quality of sputum has received considerable attention as a means of improving the reliability of sputum culture in diagnosing lower respiratory tract infections(LRTI). Materials and methods : The study was conducted in the Department of Microbiology, RIMS, Ranchi for a period of 9months from November 2016 to August 2017. Gram staining and culture was performed on expectorated sputum from clinically suspected cases of LRTI. Bartletts criteria was used for assessing the acceptability of sputum samples . Gram stained smears of sputum were observed under microscope for the presence of organisms, polymorphs and squamous epithelial cells. Culture of purulent part of sputum was performed . Standard microbiological methods were used to identify bacterial isolates . Kirby Bauer disc diffusion method on Muller Hinton agar was performed for antibiotic sensitivity testing. Results: A total of 341 sputum samples were collected out of which 232 samples were acceptable. Bartlett�s criteria was used to screen the sputum samples based on which 68% were acceptable and 32% were unacceptable. Among acceptable category 180(77.5%) samples showed culture positivity. Klebsiella pneumoniae(29.4%) was the most common isolate followed by Pseudomonas aeruginosa(21.1%) , Staphylococcus aureus(13.9%) and Streptococcus pneumoniae(11.7%) . Conclusion: It is important to receive good quality expectorated sputum and not saliva for Gram stain and culture for proper diagnosis of etiological agents of LRTI, so that a high diagnostic yield for clinically suspected LRTI becomes inevitable.