Antibacterial Properties of Nonsteroidal Anti-inflammatory Drugs and Proton Pump Inhibitors Against Enterococcus faecalis: An In Vitro Comparative Study.

Background Enterococcus faecalis is a common cause of persistent endodontic infections due to its resistance to conventional treatments. While triple antibiotic paste (TAP) is effective, concerns about antibiotic resistance have led to interest in nonantibiotic alternatives. Nonsteroidal anti-inflammatory medications (NSAIDs) and proton pump inhibitors (PPIs) have shown promising antibacterial activity. This study aimed to compare the efficacy of diclofenac sodium (DS), TAP, and their combinations with pantoprazole against E. faecalis in vitro. Methodology This in vitro study evaluated the antibacterial efficacy of DS, TAP, and pantoprazole (a PPI), both individually and in combination, against E. faecalis (ATCC 29212). Standardized bacterial suspensions were tested using the agar well diffusion method on Mueller-Hinton agar plates. A total of 140 plates were divided across five groups to assess the antimicrobial zones of inhibition. Test compounds were freshly prepared and introduced into wells under aseptic conditions, followed by incubation at 37°C for 24 hours. Inhibition zones were measured digitally in mm, and data were statistically analyzed using analysis of variance and t-tests, with significance set at p-values <0.05. Results In this study, TAP exhibited the highest antibacterial activity among the standard drugs, followed by DS, while PPI showed the least efficacy. However, when combined with PPI, both TAP and DS demonstrated significantly enhanced zones of inhibition against E. faecalis, with the TAP + PPI group showing the greatest effect (40.05 ± 0.91 mm), followed by DS + PPI (37.06 ± 0.90 mm). These differences were statistically significant (p < 0.0001), indicating a synergistic benefit from combining PPI with either TAP or DS. Conclusions The combination of TAP + PPI showed the highest antibacterial efficacy against E. faecalis, followed by DS + PPI, TAP, DS, and PPI alone. Drug combinations demonstrated significantly greater inhibition zones compared to individual agents, indicating enhanced antimicrobial activity.