In vitro evaluation of the interaction between tea extracts and penicillin G against staphylococcus aureus

The herb-drug interaction between tea (Carmelia sinensis) extract and penicillin G (Pen G) was investigated against three strains of Staphylococcus aureus using pair combinations in an in vitro decimal assay for additivity test. Results showed that the interactions between penicillin G and teaextracts were mainly additive against the three strains of S. aureus. This suggests that the concomitant administration of tea and Pen G may not impair the antimicrobial activity of Pen G

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

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 ofseventy-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 isolateswere sensitive to the fluoroquinolones (ciprofloxacin, 85.3%, norfloxacin 93.3%) and the aminoglycosides (streptomycin 90%, gentamycin 89.3%). However, the isolates demonstratedsignificant 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 demonstratedresistance 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 shouldtherefore be geared at standardizing the quality of HMPs via strict adherence to Good Manufacturing Practice (GMP)

In vitro interaction of ampicillin with ciprofloxacin or spiramycin as determined by the decimal assay for additivity technique

The in vitro interactions of Ampicillin (AMP) with Ciprofloxacin (CIP) and Ampicillin with Spiramycin (SPIR) were evaluated against Staphylococcus aureus ATCC 12600 using the Decimal Assay for Additivity (DAA) technique. Most of the combinations of CIP/AMP with Biological Equivalent Factor (BEF) (5/30mg) or SPIR/AMP with biological equivalent factor (BEF) (10.96/30mg) against Staphylococcus aureus ATCC 12600 showed synergism. Given that the test organism was intrinsically resistant to either SPIR or AMP alone (MIC, 15.6 and 23.4 µg/ml respectively), the observed in vitro synergism could be therapeutically exploited. Moreover, the present data further authenticates the potential applicability of the DAA technique in selecting suitable antibiotic combinations prior to combined antimicrobial therapy. Keywords: decimal assay for additivity (DAA), antibiotic interaction, Ciprofloxacin, spiramycin, ampicillin Nigerian Journal of Health and Biomedical Sciences Vol. 5(1) 2006: 12-1