In vitro antimicrobial activity, antibioresistance reversal properties, and toxicity screen of ethanolic extracts of Heracleum mantegazzianum Sommier and Levier (giant hogweed), Centaurea jacea L. (brown knapweed), and Chenopodium album L. (Pigweed): Three invasive plants.

Background: Plants, including invasive ones, can play a significant role in the fight against antibiotic resistance and the search for new antimicrobials. Aims: The present study aimed at assessing the antimicrobial activity, antibioresistance reversal properties, and toxicity of four samples from invasive plants, namely, Heracleum mantegazzianum (leaves and flowers), Chenopodium album (leaves), and Centaurea jacea (flowers). Methods: The extraction of active compounds was done with ethanol (80%, v/v) and the extraction yields were calculated. Antimicrobial activity was studied using the agar-well diffusion method against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538, and Candida albicans ATCC 10231. Minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined using the mircodilution method. The antibioresistance reversal properties were assessed using the checkerboard method and the toxicity of the extracts was studied using the larval form of the Greater Wax Moth (Galleria mellonella). Results: The mass yields were 11.9, 15.0, 18.2, and 21.5, respectively, for C. jacea flower (CJF), H. mantegazzianum flower (HMF), H. mantegazzianum leaf (HML), and C. album leaf (CAL). The highest inhibition diameters (ID) were found with HMF, CAL, CJF, and HML against S. aureus with 26.6, 21.6, 21.0, and 20.0 mm, respectively. Only CJF and HMF were active against E. coli with respective ID of 15.3 and 19.0 mm. Except HMF (ID = 13.6 ± 2.0 mm), no other extract was active against C. albicans. Moreover, HMF exhibited the lowest MIC (0.5 mg/ml) and the lowest MBC (1 and 4 mg/ml) against both S. aureus and E. coli. Regarding the synergy test, an additional effect [0.5 ≤ fractional inhibitory concentration (FIC) ≤ 1] was found in almost all the combinations antibiotics + extracts excepted for HMF + (Kanamycin or Ampicillin) against S. aureus and CJF + Ampicillin against E. coli where we found synergy effect (FIC ≤0.5). The median lethal doses (LD50s) of HMF, HML, CAL, and CJF were 20.2, 0.58, 13.2, and 4.0 mg/ml, respectively. Conclusion: Only the ethanolic extract of HMFs showed noteworthy broad spectrum antimicrobial activity.

The public health issue of antibiotic residues in food and feed: Causes, consequences, and potential solutions.

Antibiotics are among the essential veterinary medicine compounds associated with animal feed and food animal production. The use of antibiotics for the treatment of bacterial infections is almost unavoidable, with less need to demonstrate their importance. Although banned as a growth factor for a few years, their use in animals can add residues in foodstuffs, presenting several environmental, technological, animal health, and consumer health risks. With regard to human health risks, antibiotic residues induce and accelerate antibiotic resistance development, promote the transfer of antibiotic-resistant bacteria to humans, cause allergies (penicillin), and induce other severe pathologies, such as cancers (sulfamethazine, oxytetracycline, and furazolidone), anaphylactic shock, nephropathy (gentamicin), bone marrow toxicity, mutagenic effects, and reproductive disorders (chloramphenicol). Antibiotic resistance, which has excessively increased over the years, is one of the adverse consequences of this phenomenon, constituting a severe public health issue, thus requiring the regulation of antibiotics in all areas, including animal breeding. This review discusses the common use of antibiotics in agriculture and antibiotic residues in food/feed. In-depth, we discussed the detection techniques of antibiotic residues, potential consequences on the environment and animal health, the technological transformation processes and impacts on consumer health, and recommendations to mitigate this situation.