Synergistic effects of noscapin and ofloxacin in fluoroquinolone resistant enterobacteriaceae

Infections diseases afflict millions of people every day inflicting over thousands of death each day. Antibiotic resistance in pathogenic bacteria has been occurring with increasing proportions in all parts of the world. This can complicate therapeutic approaches especially in people with immunodeficiencies, AIDS patients, and in cancer victims. This problem also necessitates introduction of new antimicrobial agent with increased potency or trying to maximize therapeutic potencies of the available drugs in order to counter the problem of antimicrobial resistance. Plant extracts have been used in the last two decades to increase the antimicrobial potencies of various antibiotics. In this survey, the synergistic effect of Noscapin on Ofloxacin has been tested on a range of clinical Enterobacteriaceae isolates which were resisted to fluoroquinolones. Twenty five Escherichia coli strains isolated from sick people which were resistant to ofloxacin according to agar diffusion NCCLS advised methods were collected. Subsequently, the minimal inhibitory concentration (MIC) of each of the isolate, performed by serial dilution method, was determined toward Ofloxacin alone or in combination with Noscapin. The results indicated that the MIC of the 25 E. coli isolates towards Ofloxacin alone was in the range of 8-128 µg/ml. The MIC values to Noscapin alone were in the ranges of 0/5-1.0 µmol/ml. According to these results, Noscapin was used at the final concentration of 0.25 µmol/ml for all of the synergestic studies. Combination of Noscapin with ofloxacin was able to decrease the MIC values 2-8 fold for the E. coli isolates. This clearly points to the additive and synergistic effect of Noscapin on Ofloxacin against drug-resistant bacteria. By performing further studies, the additive effects of other plant extracts on various antibiotics can be studied.