Prevalence and antimicrobial susceptibility of bacteria isolated from herbal medicines vended in Morogoro municipality, Tanzania

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Sokoine University of Agriculture


Herbal medicines are plant-derived materials used as therapeutic substances or dietary supplements. A cross-sectional study was conducted to estimate prevalence of bacteria and antimicrobial susceptibility of Escherichia coli and Staphylococcus aureus in herbal medicinal products (HMP) vended in Morogoro Municipality, Tanzania. Fifty samples of HMPs were purchased from vendors in six locations in Morogoro Municipality. The samples were analysed by using laboratory standard procedures such as total viable count, isolation and characterization of bacteria and agar disc diffusion method to determine antimicrobials susceptibility. Approximately 88% of HMP had significantly (P<0.05) higher total microbial counts than the recommended level of ≤ 103cfu/ml for HMP intended for human consumption, ≤ 105 cfu/ ml for pre-treated products and no E. coli or Salmonella spp. allowed to be present at any level by World Health Organization (WHO) and British Pharmacopeia standards. The results showed that 10% of HMP were contaminated with E. coli and 8% with S. aureus. Furthermore, E. coli and S. aureus isolated were susceptible to ciprofloxacillin (CIP) but resistant to nalidixic acid (NA), cefatoxime (CTX), oxacillin (OX), co-trimoxazole (SXT) and vancomycin (VA). In this study E. coli isolates showed more resistance against CTX, OX, VA and SXT while S. aureus had high resistance against NA. The study also observed unhygienic handling practices and low level of safety knowledge of the HMP vendors. This could predispose patients and other consumers of the products to the risk of infections with pathogenic and antimicrobial resistant bacteria. It is recommended that food scientists, health officers, extension officers and other stakeholders should play their roles of training and enforcing quality assurance through monitoring the production and distribution of HMP to safeguard consumers.


Masters Thesis


Prevalence, Antimicrobial susceptibility, Bacteria, Herbal medicines, Morogoro, Tanzania