Evaluation of synergism between Cefotaxime and Allium sativum against Extended-spectrum beta-lactamase and Ambler class C co-producers

Abstract

The present study evaluates the synergistic association between Cefotaxime and aqueous garlic (Allium sativum) extract (AGE) on extended spectrum beta-lactamase (ESBL) and Ambler Class C (AmpC) co-producing Escherichia coli strains from skin and soft tissue infections (SSTIs). Ceftazidime-resistant E. coli strains were screened for betalactamase production by phenotypic confirmatory disc diffusion test (PCDDT) and E-test. Antibacterial activity of AGE was examined by the disc diffusion method and the minimum inhibitory concentration (MIC) of Cefotaxime and AGE was determined. The synergistic association between Cefotaxime and AGE was evaluated by calculating the fractional inhibitory concentration (FIC) index, time-kill kinetics assay (TKA), and scanning electron microscopy (SEM). The zone of inhibition by AGE against the 27 E. coli co-producers of ESBL and AmpC ranged from 17 to 30 mm. The average MIC of Cefotaxime and AGE was found to be 570 μg/ml and 0.86% (4.28 mg/ml), respectively. The FIC index obtained by the checkerboard method established a synergistic association between Cefotaxime and AGE in 10 (37%) test strains, which was confirmed by TKA. The SEM analysis revealed complete cell degradation at 8 hours on the treatment with Cefotaxime-AGE combination. It can be stated that the AGE may aid Cefotaxime in the treatment of beta-lactamase producing E. coli strains from SSTIs.

Structural elucidation, mechanism of action, antibacterial proficiency and synergistic forte of purified Euphorbia hirta whole plant extract against multi-drug resistant otitis media infection

“…Even though the synergism detected using checkerboard method was not established by the time kill curve in this study, the lack of antagonistic effect as shown in the E. hirta whole plant acetone extract and honey mixture is an inspiring outcome which suggests that purified acetone extracts and honey has potential to be effective as combination or mono therapy, also they may contain a myriad of bioactive constituents that can enhance the activity of ciprofloxacin against drug resistant bacteria isolates associated with OM. We combined E. hirta whole plant acetone extract, honey and ciprofloxacin in this study to treat the MDR test isolates, the treatment's time kill assay showed bactericidal activity against P. mirabilis isolate after 24 h. This is analogous with report by Abegunde et al (2018) and Shah & Williamson (2019), in Nigeria and India respectively. This bactericidal action recorded in this study shows E. hirta acetone extract,…”

“…This study also revealed low fractional inhibitory concentration index value on P. mirablis (0.02) when E. hirta whole plant acetone extract and honey was mixed with ciprofloxacin. This correlate with Shah and Williamson (2019) who showed low fractional inhibitory index value when aqueous garlic extract was combined with antibiotics against resistant strain of E. coli in India. The synergistic effects of E. hirta whole plant acetone extract, honey and ciprofloxacin shown in this study reveals high level of ciprofloxacin potentiation against multidrug resistant P. mirablis isolate.…”

“…No combination had synergistic effect (> 2 log10 cfu/mL reduction from the most active single agent from the kill assay; as oppose to the report by Shah & Williamson (2019) that showed synergistic effect in the combination of garlic and cefotaxime against extended spectrum beta-lactamase E. coli isolate with a 3 log10 cfu/mL reduction from cefotaxime. Even though the synergism detected using checkerboard method was not established by the time kill curve in this study, the lack of antagonistic effect as shown in the E. hirta whole plant acetone extract and honey mixture is an inspiring outcome which suggests that purified acetone extracts and honey has potential to be effective as combination or mono therapy, also they may contain a myriad of bioactive constituents that can enhance the activity of ciprofloxacin against drug resistant bacteria isolates associated with OM.…”

“…The checker board method described by Shah and Williamson (2019) with modification was used to detect the synergism in the combinations. The extract, honey, antibiotics were combined by incorporating them into sterilized molten nutrient agar.…”

“…The kill time method, using the broth macrodilution technique as described by Shah and Williamson (2019) with modifications was used to assay the antibacterial effect of the combinations. The extract, honey and antibiotics combination that showed synergistic interaction in the checkerboard assay were dispensed into 50 ml of nutrient broth at the minimum inhibitory concentration.…”