Analysis Of Sputum Culture And Gram Staining In Subjects With Lower Respiratory Tract Infection: A Microbiological Assessment

Abstract

Background: To diagnose the LRTIs (lower respiratory tract infections) in the microbiological laboratory, the most frequently
employed method is the microscopic examination of expectorated sputum samples. These sputum samples are generally
contaminated with the normal flora that is resident of the oropharynx. To manage and diagnose lower respiratory tract infections,
sputum collection, culture, and microscopy are vital.
Aim: The present study was conducted to analyse the sputum culture and gram staining in subjects with lower respiratory tract
infections.
Materials & Methods: The study included 140 sputum samples where culture and gram-staining were done. Microscopic examination
of the gram-stained sputum smears was done to assess the presence of epithelial cells, pus cells, or organisms. Bartlett’s grading
system was used to assess the quality of the expectorated sputum samples. Bacterial isolates were identified using standard protocols.
On Mueller Hinton agar, the Kirby Bauer disc diffusion method was used for testing antibiotic susceptibility.
Results: In 140 processed sputum samples, it was seen that there were 55% (n=77) acceptable samples and 45% (n=63) nonacceptable samples. Total potential pathogens obtained from the study samples were 62.85% (n=88) samples were from acceptable
samples, in 76.13% (n=67) potential pathogens were isolated, whereas, from non-acceptable samples, potential pathogens were
isolated from 23.86% (n=21) samples. On assessing the organisms isolated from the study subjects, it was seen that the most common
isolated organism was Klebsiella pneumoniae isolated from 28.40% (n=25) samples followed by Pseudomonas aeruginosa in 14.77%
(n=13) samples, Staphylococcus aureus in 13.63% (n=12) study samples, Escherichia coli in 12.5% (n=11) samples, Streptococcus
pyogenes in 7.95% (n=7) samples, Klebsiella oxytoca in 6.81% (n=6) study samples, Streptococcus pneumoniae in 5.68% (n=5)
study samples, Acinetobacter baumannii, Citrobacter koseri, and Enterobacter aerogenes in 3.40% (n=3) study samples
Conclusion: The present study concludes that in subjects with Lower respiratory tract infections, good quality sputum must be
obtained, and initial screening of the sputum should be done to obtain.