Susceptibility pattern of clinical isolates of uropathogens from Southwest Nigeria to antibiotics and extracts of Dalbergia latifolia Roxb (Fabaceae)

Abstract

Background: Resistance of uropathogens toconventional antibiotics is increasing, thus creating the need to search for newer and effective antimicrobial agents to treat urinary tract infections (UTI). Methods: The susceptibility pattern of twenty clinical isolates of uropathogenic bacteria to standard antibiotics and extracts of Dalbergia latifolia was investigated using Agar Disc and Agar Well Diffusion methods, respectively. Minimum Inhibitory Concentrations (MICs) of the extracts were determined by Agar Dilution method on some of the uropathogens. Results: All the test pathogens were resistant to Amoxicillin, Cotrimoxazole and Augmentin. The isolates had 25 % (4), 12.5% (2), 18.75% (3), 68.75% (11) susceptibility to Nitrofurantoin, Gentamicin, Nalidixic acid and Ofloxacin respectively while 87.5% showed resistant to Tetracycline. The E. coli and K. pneumoniae strains had the highest susceptibility to Ofloxacin while P. mirabilis 4 was susceptible to Ofloxacin. The uropathogenic S. aureus was highly resistant to the antibiotics, however S. aureus 3 and S. aureus 4 were susceptible to gentamicin while S. aureus 1 and S. aureus 5 were susceptible to chloramphenicol. Gentamicin and chloramphenicol were the most active on S. aureus. The extracts showed good activity on most of the uropathogens in which 81.81 % (18), 9.0% (2) and 63.63% (14) of the test pathogens were susceptible to the leaf, stem and root (successively) of D. latifolia. The MIC values of extracts on test organisms ranged from 0.063 to 2.0 mg/mL. Conclusion: The results revealed varied patterns of susceptibility of the uropathogens to conventional antibiotics, necessitating rational use of antibiotic in routine treatment of UTI to prevent development of resistance. Further, activity of D. latifolia extracts on the uropathogens justified its folkloric use and underlined the potentials of the plant to furnish antimicrobial agents for the treatment of UTIs, including those resistant to conventional antibiotics.