Influence of First‐Line Antibiotics on the Antibacterial Activities of Acetone Stem Bark Extract of Acacia mearnsii De Wild. against Drug‐Resistant Bacterial Isolates

Abstract

Background. This study was aimed at evaluating the antibacterial activity of the acetone extract of A. mearnsii and its interactions with antibiotics against some resistant bacterial strains. Methods. The antibacterial susceptibility testing was determined by agar diffusion and macrobroth dilution methods while the checkerboard method was used for the determination of synergy between the antibiotics and the extract. Results. The results showed that the susceptibility of the different bacterial isolates was concentration dependent for the extract and the different antibiotics. With the exception of S. marcescens, the inhibition zones of the extract produced by 20 mg/mL ranged between 18 and 32 mm. While metronidazole did not inhibit any of the bacterial isolates, all the antibiotics and their combinations, except for ciprofloxacin and its combination, did not inhibit Enterococcus faecalis. The antibacterial combinations were more of being antagonistic than of being synergistic in the agar diffusion assay. From the macrobroth dilution, the extract and the antibiotics exerted a varied degree of inhibitory effect on the test organisms. The MIC values of the acetone extract which are in mg/mL are lower than those of the different antibiotics which are in μg/mL. From the checkerboard assay, the antibacterial combinations showed varied degrees of interactions including synergism, additive, indifference, and antagonism interactions. While antagonistic and additive interactions were 14.44%, indifference interaction was 22.22% and synergistic interaction was 37.78% of the antibacterial combinations against the test isolates. While the additivity/indifference interactions indicated no interactions, the antagonistic interaction may be considered as a negative interaction that could result in toxicity and suboptimal bioactivity. Conclusion. The synergistic effects of the herbal-drug combinations may be harnessed for the discovery and development of more rational evidence-based drug combinations with optimized efficiency in the prevention of multidrug resistance and therapy of multifactorial diseases.

Dietary encapsulated essential oils and organic acids mixture improves gut health in broiler chickens challenged with necrotic enteritis

“…In addition, several studies have shown improved gut morphology and decreased gross intestinal lesion scores in NE-infected broiler chickens fed either EO-supplemented [18] or OA-treated diets [28]. Intestinal bacterial translocation to internal organs and serum FITC-D levels post-FITC-D gavage are also two important parameters commonly used to indirectly evaluate quality and extent of intestinal injury [54]. Our study further found that infected birds fed BLJ showed P-values represent the main effect of the diet, the main effect of the NE challenge, and the interaction between the dietary treatments and NE challenge that the EOA combination can decrease C. perfringens colonization and proliferation in chicken guts [54].…”

“…Intestinal bacterial translocation to internal organs and serum FITC-D levels post-FITC-D gavage are also two important parameters commonly used to indirectly evaluate quality and extent of intestinal injury [54]. Our study further found that infected birds fed BLJ showed P-values represent the main effect of the diet, the main effect of the NE challenge, and the interaction between the dietary treatments and NE challenge that the EOA combination can decrease C. perfringens colonization and proliferation in chicken guts [54]. Improved gut morphology, reduced gut lesion scores and decreased intestinal epithelial permeability in NEinfected birds that received BLJ were possibly attributed to the antibacterial traits of the EOAs [34], EOs [11] or OAs [25].…”

Synergistic effects of natural products and commercial antibiotics—A mini–review 2010–2015

“…Bacterial strains usually were clinical isolates with a specific resistance (no full antibiogram reported). In the reviewed reports, the utilization of standard strains were the exception more than the rule (3% of the tested strains) [32][33][34][35][36][37][38][39][40] . In almost all the cases, resistant opportunistic bacteria were the target, the most frequently strain tested were clinical isolates of MRSA.…”

Nimbolide from Azadirachta indica and its derivatives plus first-generation cephalosporin antibiotics: a novel drug combination for wound-infecting pathogens

“…With the increase in the prevalence of multidrug resistant wound pathogens, synergism testing using various combinations of plant compound and their corresponding synthetic derivatives with antimicrobial drugs could be a more powerful tool in helping to select appropriate antimicrobial therapy to control pathogens. [51][52][53] The indiscriminate use of various antibiotics in the treatment of bacterial infections especially against wound pathogens has led to the emergence and spread of resistant bacterial strains, and this in turn resulted in a great loss of clinical efficacy of previously effective first-generation antibiotics which results in shifting of antimicrobial treatment regimen to second-generation or third-generation antibiotics that are often more expensive with many unwanted side effects to human beings. 54 In fact, studies have shown that crude extracts of plants possess the ability to enhance the activity of antimicrobial agents without causing any unwanted side effects.…”