GENETIC VARIABILITY OF LOWER RESPIRATORY TRACT PATHOGENS AND THEIR SUSCEPTIBILITY TO INDIGENOUS MEDICINAL PLANTS

Abstract

The present study was carried out to assess the antibiotic sensitivity pattern and genetic variability of selected lower respiratory tract pathogens. Also the susceptibility of these pathogens to the phytochemical constituents present in indigenous medicinal plants was also studied. Two hundred sputum samples were collected from the patients in an around Nagercoil, Tamil Nadu referred for diagnosis by physicians. Among the 200 samples, 152 samples had positive infections with 60 Gram positive and 92 Gram negative bacteria. Considering the virulence, multidrug resistance and nosocomial nature, two lower respiratory tract pathogens Acinetobacter baumannii and Klebsiella pneumoniae isolated from the sputum samples were used for further studies. The antibiotic sensitivity study of the isolates of A. baumannii and K. pneumoniae revealed distinct patterns. The genetic variability studies of the bacterial isolates using RAPD assay confirmed the variation among the isolates with the definite antibiotic sensitive pattern. Three medically important plants namely Andrographis paniculata, Myristica fragrans and Achyranthes aspera were screened for their antimicrobial activity against the A. baumannii and K. pneumoniae isolates. The FT IR spectral analysis revealed the functional groups present in the phytochemical constituents and their molecular nature. The GC MS analysis revealed 42 compounds in A. paniculata, 17 compounds in M. fragrans and 18 compounds in A. aspera. The compounds possessing many therapeutic properties reported in earlier literatures were detected in the present study which includes andrographolide in A. paniculata, euginol and isoeuginol in M. fragrans and pentacosane and squalene in A. aspera. Among the three plants tested for antimicrobial activity, the methanol extract of A. paniculata showed higher and significant activity than M. fragrans and A. aspera. The methanol extract of A. paniculata showed higher antibacterial activity against A. baumannii isolates and it was on par with the standard antibio