Synergistic bactericidal profiling of prodigiosin extracted from Serratia marcescens in combination with antibiotics against pathogenic bacteria

Abstract

The emergence of multidrug-resistant (MDR) bacteria is on the rise and the situation has been worsening with each passing day, which is evident from the outpouring number of reports about how more and more pathogens are becoming resistant to even the third and fourth generations of antibiotics. Lately, combination therapies or drug synergy have been giving promising results in curbing infections since it delineates its action on multiple aspects as compared to monotherapies. In this study, we used prodigiosin, a bacterial pigment endowed with magnificent biological properties, in combination with six antibiotics to study its effect on Pseudomonas aeruginosa , Staphylococcus aureus and Chromobacterium violaceum . Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of prodigiosin against the test organisms was determined and a checkerboard assay of prodigiosin with various antibiotic combinations was performed with an aim to abate antimicrobial resistance. MIC and MBC of prodigiosin was obtained in the range of 4–16 μg/mL, which was lower than that of most test antibiotics. Coupling prodigiosin with other test antibiotics exhibited an excellent synergy profile against all test organisms and the effects were reported to be either synergistic or additive. In the case of S. aureus and C. violaceum , all combinations were found to be synergic, and remarkably for S. aureus , FBC index was reported to be as low as ≤0.25 with all of the test antibiotics. Therefore, it is deduced that prodigiosin augments and intensifies the action of antibiotics, and results in a double-whammy against the MDR strains.

Plant Triterpenoids Regulate Endophyte Community to Promote Medicinal Plant Schisandra sphenanthera Growth and Metabolites Accumulation

“…Some endophytic Bacillus sp., Xanthomonas sp., Pantoea sp., Trichoderma sp., and Fusarium sp. were treated as an effective bio-control agent against phytopathogenic fungi [20,[54][55][56][62][63][64][65][66][67][68]. As a consortium, the microbes promoted by triterpenoids are beneficial to the plant, as they can unite the inter-kingdom and the outer-kingdom microbial consortia, and also promote plant growth.…”

In vitro and in vivo evaluation of antimicrobial activity of Zooshikella marina against pathogenic bacteria causing vibriosis in aquaculture

“…In addition, the MIC and MBC values of prodigiosin extract obtained for Serratia spp. were 1-400 µg/mL against the Gram-positive bacteria S. aureus and B. subtilis and 4-800 µg/mL against the Gram-negative bacteria P. aeruginosa, C. violaceum and V. parahaemolyticus (Gohil et al, 2020;Jafarzade et al, 2013;Lapenda et al, 2015). Antimicrobials are usually regarded as bactericidal if the MBC/MIC ratio is ≤4 and bacteriostatic if this is >4 (Keepers et al, 2014;Pankey, & Sabath, 2004).…”

“…violaceum and V . parahaemolyticus (Gohil et al, 2020; Jafarzade et al, 2013; Lapenda et al, 2015). Antimicrobials are usually regarded as bactericidal if the MBC/MIC ratio is ≤4 and bacteriostatic if this is >4 (Keepers et al, 2014; Pankey, & Sabath, 2004).…”

“…Previous studies have demonstrated that prodigiosin and cycloprodigiosin inhibit the growth of a wide spectrum of Gram‐positive bacteria including Bacillus subtilis and Staphylococcus aureus , as well as of the Gram‐negative bacteria Escherichia coli , Salmonella typhimurium ; Pseudomonas aeruginosa , Chromobacterium violaceum and V . parahaemolyticus (Gohil et al, 2020; Jafarzade et al, 2013; Lapenda et al, 2015; Lee et al, 2011). In this sense, motivated by the promising antimicrobial properties of Zooshikella sp., the present study aimed to evaluate the antimicrobial activity of cell and extract from Z .…”

Antimicrobial interactions between the phytoextracts of Callistemon citrinus and Eriobotrya japonica against Streptococcus mutans

“…Fractional inhibitory/bactericidal concentration indices (FICI/FBCI) were used as reported previously by Pratoomsoot and Gohil [26–27] to determine the presence or absence of antimicrobial interactions as shown below: …”