Impact of pH on citric acid antimicrobial activity against Gram‐negative bacteria

Abstract

Significance and Impact of the Study: Citric acid (CA) is an antimicrobial molecule with three ionization states that exist in an equilibrium directly governed by pH. Traditionally, non-ionized CA was considered more antimicrobial, presumably due to the combined effects of the molecule and the acidic environment in which it occurs. By decoupling the antimicrobial impact of pH and CA on Gram-negative bacteria, it is demonstrated, for the first time, that the fully ionized CA species alone was the most effective at destroying the bacteria. The results from SEM imaging and surface-charge measurements provide further insight into the antimicrobial mode of action of CA against bacteria.

Evaluation of antimicrobial photodynamic therapy with acidic methylene blue for the treatment of experimental periodontitis

“…Negatively charged citric acid is believed to inactivate bacteria by either destabilizing the outer membrane or by sequestering essential metals from the growth environment [ 52 , 53 ]. Recently, Burel et al [ 54 ] evaluated the impact of pH on citric acid antimicrobial activity against Gram-negative bacteria. Their [ 54 ] results indicate that tribasic citric acid was the most effective in damaging the bacterial membrane.…”

“…Recently, Burel et al [ 54 ] evaluated the impact of pH on citric acid antimicrobial activity against Gram-negative bacteria. Their [ 54 ] results indicate that tribasic citric acid was the most effective in damaging the bacterial membrane. However, a reduction in the absolute number of bacteria and damages to cell walls were found regardless of the tested pH.…”

“…No similar experiment has been carried in order to evaluate the effectiveness of citric acid on targeting the membrane or killing periodontal pathogens. Hence, the promising findings of Burel et al [ 54 ] encourage further research on the plausible efficacy of using citric acid-based therapies for reducing bacterial colonization related to the pathogenesis of periodontitis.…”

Branched/Hyperbranched Copolyesters from Poly(vinyl alcohol) and Citric Acid as Delivery Agents and Tissue Regeneration Scaffolds

“…However, without gentamicin a small "zone of inhibition" was also seen in case of E. coli, due to inherent antibacterial effect of CA against Gram negative bacteria. [28] Gentamicin loaded V3 exhibited a larger inhibition zone with E. coli than V2 while those were nearly equal for both V2 and V3 with B. subtilis. Nevertheless, it was implicated that both V2 and V3 were effective towards encapsulation and release of gentamicin for which they could resist the bacterial growth more effectively than the virgin polymers.…”

Electrospun Nanofibrous Membranes Based on Citric Acid-Functionalized Chitosan Containing rGO-TEPA with Potential Application in Wound Dressings

“…The functionalization of CS with certain compounds that possess an additional number of hydrophilic functional groups, such as -OH and carboxyl (-COOH), may be an alternative. One of these compounds is citric acid (CA), a ternary carboxylic acid with high hydrophilicity and extensive applications in the food industry, chemical engineering, and medicine due to its good antibacterial activity [7]. The main roles of CA consist in maintaining the hydrophilic balance of the materials and the involvement in hydrogen bonding interactions with other biomolecules due to the increased number of -COOH functional groups [8].…”