Antimicrobial Resistance Evaluation of Organisms Isolated from Liquid Herbal Products Manufactured and Marketed in South Eastern Nigeria

Objective: To determine the susceptibility and resistance pattern of bacteria and fungi isolates obtained from herbal anti-infective liquid preparations manufactured and marketed in South-East Nigeria to conventional antibiotics.
Study Design: Experimental
Place and Duration of the study: Pharmaceutical Microbiology and biotechnology Laboratory, Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University, Agulu Campus between October 2011 and March 2012.
Methodology: Isolation and characterization of contaminating microorganisms were carried out using standard procedures. A total of forty-nine (49) bacteria and forty (40) fungi isolated from the herbal products were examined for susceptibility to conventional antibiotics using the disc diffusion method. The bacterial isolates were tested against ciprofloxacin, ofloxacin, amoxicillin-clavulanic acid, gentamicin, cefotaxime, ceftazidime, ceftriazone, sulphamethoxazole, tetracycline and ampicillin were employed while fungi isolates were tested against five common antifungal-griseofulvin, nystatin, ketoconazole, fluconazole and clotrimazole. The Multiple Antibiotic Resistance Index (MARI) of each of the isolated bacteria was obtained following the standard method.
Result: The antimicrobial susceptibility-resistance profile of the bacteria isolates revealed that most of the bacteria were sensitive to ciprofloxacin, ofloxacin, gentamicin, and ceftriaxone, On the other hand, a good number of the isolates demonstrated high level of resistance to common antibiotics like Ampicillin, amoxycillin-clavulanic acid, trimethoprim-sulphamethoxazole, and moderate level of resistance to Tetracycline, and some of the third generation cephalosporins - ceftazidime and cefotazime. Multiple Antibiotic Resistance Index (MARI) evaluation revealed that most of the isolates were resistance to more than fifty percent (50%) of the number of antibiotics used. The fungal isolates were susceptible to nystatin, ketoconazole and clotrimazole, resistance to fluconazole and high resistance recorded against griseofulvin.
Conclusion: The results of this study revealed that the herbal medications can serve as a trail of spread of antibiotic-resistance genes.