Study of Bacterial and Fungal Profile of Sputum Samples in a Tertiary Care Hospital: A Prospective Analysis

Background: Gram-stained sputum samples can be examined under a microscope to help diagnose lower respiratory tract infections in patients. When determining if a sputum sample is suitable for cultivation in the lab, Gram stain is crucial. Determining the sample's representativeness for the targeted collecting site is helpful. The purpose of this study was to evaluate the application of Gram stain in sputum examination in diagnostic microbiology and to connect Gram stain results with culture. Methods: From February 2025 to July 2025, a total of 133 sputum samples were quality assessed using Bartlett’s grading system. The total scoring was done and sample showing score of 1 and above were cultured and identified based on colony characteristics, gram staining morphology and biochemical reactions. Results: One hundred and thirty-three sputum samples were collected from patients with suspected lower respiratory tract infection. Of the 133 samples, 110(79%) were accepted and 23 (21%) were found to be unacceptable by Bartlett criteria. Potential pathogens were grown in 84 samples in the acceptable category. Normal respiratory flora were grown in 26 samples. Out of 84 samples, 63 samples were positive for bacterial growth and 21 showed fungal growth. Out of 63 bacterial growth, 44 were from in-patients and 19 were from out-patients. Among these bacterial isolates, 23 isolates were Pseudomonas aeruginosa followed by 16 isolates were Klebsiella pneumoniae, 10 isolates were E.coli, 6 isolates were Staphylococcus aureus, 2 isolates were Streptococcus species, 3 isolates were Proteus mirabilis and 3 isolates were Serratia marcesens. Conclusion: All the sputum samples should be subjected to gram staining before culture to differentiate true pathogens from contaminating flora on culture.