Susceptibility-resistance profile of micro-organisms isolated from herbal medicine products sold in Nigeria

Abstract

In order to evaluate the susceptibility and resistance pattern of bacteria and fungal isolates obtained from herbal medicine products (HMPs) marketed in Nigeria to conventional antibiotics, a total of
seventy-five (75) bacteria and fifty-two (52) fungi isolated from the HMPs were screened for susceptibility to conventional antibiotics using the disc diffusion method. Most of the bacteria isolates
were sensitive to the fluoroquinolones (ciprofloxacin, 85.3%, norfloxacin 93.3%) and the aminoglycosides (streptomycin 90%, gentamycin 89.3%). However, the isolates demonstrated
significant resistance to common antibiotics like penicillins (augmentin [amoxycillin-cavulanic acid combination] 80%, cloxacillin 88.3%, ampicillin 56%), cephalosporins (rocephine [ceftriaxone] 65%,
ceporex [cephalexin] 80%, cefuroxime 100%), chloramphenicol (66.7%), nitrofurantoin (100%) and cotrimoxazole (93.3%). Most of the fungal isolates were resistant to griseofulvin (67.3%) but susceptible to nystatin (73.1%), ketoconazole (98.1%), tioconazole (100%), clotrimazole (78.9%) and miconazole (88.5%). A significant proportion of bacteria and fungi isolated from these HMPs demonstrated
resistance to conventional antibiotics. The present study therefore reveals that HMPs may represent novel routes of spread of antibiotic-resistant genes especially in developing countries. Efforts should
therefore be geared at standardizing the quality of HMPs via strict adherence to Good Manufacturing Practice (GMP).