Bacterial pathogens from lower respiratory tract infections: A study from Western Rajasthan

Respiratory tract infections are the most common diseases that are associated with social burden for the patient. Western Rajasthan has cases of Cystic fibrosis due to migrant population. The dry and dusty environment has led to prevalence of silicosis and COPD. As per IDSA (2018) guidelines, patients attending Out-Patient Department do not need microbiological investigations for lower respiratory tract infections (LRTI) except for influenza and tuberculosis.

This study was conducted to identify the bacterial aetiology of LRTI among patients who attended AIIMS, Jodhpur, and to ascertain the current scenario of bacterial susceptibility in respiratory tract infections in order to optimize empiric therapy in Hospitals ad community.

In total, 1,775 lower respiratory tract samples were received in Bacteriology Section of Microbiology Department (January 2017 to December 2018). Bartlett's criteria were stringently used to assess quality of specimen. Semiquantitative cultures were done for tracheal aspirate and bronchoalveolar lavage samples. Following culture, the isolated organisms were identified and antimicrobial sensitivity was performed according to CLSI.

Total 769 bacterial pathogens were isolated from 1,775 samples collected from cases of VAP, HAP, CAP, COPD, and cystic fibrosis. Pseudomonas species was the commonest isolate (31%), followed by Klebsiella pneumonia (21.3%), Acinetobacter species (17.5%), Escherichia coli (15.4%), and Staphylococcus aureus (5%). Others include Group A β-hemolytic Streptococcus, Burkholderia cepacia complex, Stenotrophomonas maltophilia, and Nocardia. Gram-negative organisms showed increased resistance to routinely used antibiotics. Gram-positive organisms showed 100% susceptibility to vancomycin, linezolid, and clindamycin.

Cotrimoxazole, βL-βLIs, aminoglycosides, and all second-line antibiotics tested were effective for treatment of RTIs.