Synergistic Combinatorial Strategy for Combating Antimicrobial Resistance (AMR) in Clinical Bacteria by Combining Antibiotics with Plant Extracts

Abstract

Bacteria resistance to antibiotics used for the treatment of infections and diseases is of global concern. Medicinal plants have been used as the primary sources of plants' active ingredients or lead compounds in drug development. The combination of various antimicrobial agents to obtain a synergistic effect is considered an ideal strategy for combating bacteria resistance. In this work, a constant repetitive synergy in all combinations was achieved by adding 0.3 mL of concentrated tetraoxosulphate (vi) acid, H₂SO₄ in a mixture of Calotropis procera extract separately with (a) 1 mg/mL Amoxicillin, (b) 1 mg/mL Ampicillin, (c) 100 µg/mL Azithromycin and (d) 100 µg/mL Ampicillin and were heated at 110 °C for 20 minutes. Higher zones of inhibitions were observed at 16.7 mm for Salmonella  spp, 16.4 mm for Shigella spp, 16.8 mm for Staphylococcus aureus, 21.3 mm for Escherichia coli and 22.4 mm for Streptococcus spp in situations where the antibiotics alone zone of inhibition was 0 mm at the same concentration of a, b, c, and d. These increase the regular probability model of obtaining synergism in plant extracts combination with antibiotics as shown by multiple literatures from 33% to 66% at antibiotic concentration of 100 µg/mL and 100% at antibiotic concentration of 1 mg/mL. The validation process using Piliostigma reticulatum extract shows that a volume of 0.1 mL of concentrated tetraoxosulphate (vi) acid in 2 mL of the mixture was enough to induce synergism to combat bacteria resistance. This work shows a cost-effective method where the antimicrobial activity of ineffective antibiotics can be enhanced and optimized using plant extracts. It can also be explored and applied in different ways to identify novel compounds, and isolate and purify their active principles for selectivity, efficacy, safety and their development as clinical trial candidates in antiviral and anticancer research to overcome enormous health challenges.