In this study, herbal preparations contained varying degrees of both bacteria and fungi as common contaminants .This has also been reported in similar studies by Archibong and colleagues [20-22]. Of concern is the high levels of contaminants such as B. subtillis, C. freundi, C. divergens, E. cloacae and P. mirabilis although some had acceptable values for Enterobacter cloacae, Rhodotorula and Aspergillus spp, Staphylococcus Aureus, Klebsiella spp according to WHO standards. This is similar to studies done in Mwanza with the exception of Shigella and Salmonella that we didn’t obtain [23, 24].
Contamination of these herbal preparations could be resulting from the methods involved in the production processes as previously reported by [20, 25, 26]. Storage conditions, methods of drying herbal raw materials such as roots, leaves and stems, bark, improper handling, and the soil from which raw materials are obtained may contribute to the presence of these contaminants in the herbal products.
Presence of microorganisms in therapeutic herbal preparations incapacitates the pharmacological activity of the herbal products and contributes to secondary infections to the consumers. Previous studies have reported that the majority of these isolates are implicated in causing various disease conditions including gastritis. The cultivation of high numbers of Bacillus subtilis could be because of inadequate heat processing methods, improper handling of the products, and contaminated processing equipment. Our results are in agreement with that obtained by Oluwatoyin and colleagues [24, 27] which found that most herbal remedies were contaminated because of improper handling of the products, and contaminated processing equipment used in the production process.
Bacillus subtilis is not considered a human pathogen nor is it toxigenic like some other members of the genus, however in immune-suppressed individuals, it’s implicated in various systemic infections such as endocarditis, meningitis [26-28].
On the other hand, the presence of members of the Enterobacteriaceae family such as C. freundi , C. divergens , E. cloacae , P. mirabilis, Enterobacter cloacae and Klebsiella spp is an indication of fecal contamination. This revealed poor hygienic practices of the herbalists in the process of production and handling of these products [24, 25, 29]. These results are similar to those done in Croatia and Tanzania, .They are known food borne pathogens and thus implicated in food poisoning and diarrhea diseases [25, 30, 31].
Not only did we obtain the above but also Staphylococcus aureus was also identified in this study, S. aureus has also been reported in similar study done in Brazil and Kenya [24, 25] except that its prevalence was higher compared to our study and its implicated in scalded skin syndrome, wound abscess, and gastroenteritis[25, 32].
Microbial analysis of these samples also indicated the presence of molds, especially Aspergillus and Rhodotorula species. These have also been reported in similar studies done in Brazil [25, 33]. Since fungi are ubiquitous in nature, their presence reveals that it could be because of improper storage and handling practices of raw materials during pre-and post-harvesting and processing periods. Rhodotorula spp is known to have high affinity for plastics, therefore its presence indicates poor packaging of the products since the majority of the herbal preparations were sold in unauthentic plastic bottles which appeared to have been used for other products such as commercial mineral water [34, 35].
With all negative impacts of the contaminants mentioned above, Rhodotorula was’t left out. Previously it was considered nonpathogenic but has emerged as pathogenic opportunists that may colonize susceptible patients, and it causes bloodstream infections, meningeal and skin infections [36-38]. Aspergillus spp causes a range of diseases referred to as áspergillosis with a variety of clinical syndromes, the spectrum of these illness depending on host pathogen interactions. These include invasive pulmonary aspergillosis, chronic pulmonary aspergillosis, and allergic Broncho pulmonary aspergillosis.[39-41].
Invitro- antibacterial activity in this study was carried out on targeted standard organisms, namely, S.aureus ATTC 25923, E. coli ATTC 25922, P.aeruginosa ATTC 27583 and C. albicans ATTC 10231.
Herbal extracts have proven antibacterial activity in studies reported previously [26, 42-44]. This is similar to what we obtained in this study. We established that majority of the extracts were active against S .aureus, followed by E.coli, C .albicans, and least against P.aeruginosa. This is in agreement with other studies by Shu and collegues [26, 43].
However, effectiveness was established by determining Minimum Inhibitory Concentrations, in this context, the most effective crude extract regarded as sensitive should have an MIC of <100mcg/mL, and that >1000mcg/mL is regarded as resistant[45, 46] .In our study, none of the samples had an MIC <100mcg/mL, all were >1000mcg/mL. This could be because of the inadequate and improper purification methods involved in extraction.
Our results are similar to those obtained in Northern Peru[47, 48] but contrally from those obtained by Wong and colleagues[49, 50].