Enhanced meropenem activity and stability following load in Polyvinyl alcohol nanofiber scaffolds with sitagliptin as quorum sensing inhibitor on Pseudomonas aeruginosa

Abstract

Background: The increasing resistance of bacteria to conventional antibiotics poses a significant health challenge. Innovative strategies, such as combining antibiotics with agents like quorum sensing inhibitors (QSIs), have been developed to combat this issue. QSIs enhance antibiotic efficacy without inhibiting bacterial growth, minimizing the risk of resistance.

Aims: Evaluate the combined effect of Sitagliptin (STG) as a QSI with Meropenem (MER), fabricate drug-loaded Polyvinyl Alcohol (PVA) nanofibers, and investigate their antimicrobial activity against standard Pseudomonas aeruginosa (PAO1) and carbapenem-resistant P. aeruginosa (CRPA).

Methods: The combinatorial effect was assessed using a checkerboard assay. PVA/STG, PVA/MER, and PVA/STG/MER nanofibers were fabricated with varying concentrations of STG (2, 4, 8 mg/mL) and MER (5, 7, 9 mg/mL) via electrospinning. Characterization was performed using FTIR, XRD, and SEM techniques.

Results: STG significantly reduced the minimum inhibitory concentration (MIC) of MER. The 1:2 STG to MER ratio exhibited the highest antimicrobial activity, achieving a comparable zone of inhibition to the highest concentration of MER while utilizing nearly half the amount of MER. The stability of the loaded scaffolds was maintained over three months at 2-8 °C.

Conclusions: Our results underscore the successful fabrication of nanofiber scaffolds and the effectiveness of STG and MER-loaded nanofibers as promising wound dressings for cutaneous P. aeruginosa infections. This study highlights the potential of our innovative nanofiber system to enhance treatment efficacy against multidrug-resistant bacteria, offering a personalized and rapid response wound dressing solution for medical professionals. Ultimately, it shows promise to improve patient recovery and quality of life while minimizing systemic side effects.

Keywords: Antibacterial activity; Electrospinner; Meropenem; Nanofibers; Sitagliptin.

Fig. 1

FTIR spectra of (A) STG, (B) PVA + 2 mg/mL STG, (C) PVA + 4 mg/mL STG, (D) PVA + 8 mg/mL STG, (E) MER, (F) PVA + 5 mg/mL MER, (G) PVA + 7 mg/mL MER, (H) PVA + 9 mg/mL MER, (I) PVA, (J) PVA +(1 STG : 1 MER), (k) PVA +(2 STG : 1 MER), (L) PVA+(1 STG : 2 MER)

Fig. 2

XRD diffractometry patterns of (A) STG, (B) PVA + 2 mg/mL STG, (C) PVA + 4 mg/mL STG, (D) PVA + 8 mg/mL STG, (E) MER, (F) PVA + 5 mg/mL MER, (G) PVA + 7 mg/mL MER, (H) PVA + 9 mg/mL MER, (I) PVA, (J) PVA +(1 STG : 1 MER), (K) PVA +(2 STG : 1 MER), (L) PVA +(1 STG : 2 MER)

Fig. 3

SEM images and fiber diameter histogram of (A) PVA, (B) PVA + 2 mg/mL STG, (C) PVA + 4 mg/mL STG, (D) PVA + 8 mg/mL STG, (E) PVA + 5 mg/mL MER, (F) PVA + 7 mg/mL MER, (G) PVA + 9 mg/mL MER, (H) PVA +(1 STG : 1 MER), (I) PVA +(2 STG : 1 MER), (J) PVA +(1 STG : 2 MER), all captures are at magnification 8000x, scale10µm

Fig. 4

Checkerboard showing effect of Sitagliptin-Meropenem combinations against P. aeruginosa strains. The violet color represents growth inhibition (MIC), green color indicates the additive effect with growth inhibition. Blue shows no reduction in the growth (no effect) based on the visible turbidity. The P. aeruginosa strains were treated with fractional concentrations of Meropenem and Sitagliptin in 96-well plate containing MHB for 24 h. The growth based on visible turbidity was used for interpreting the results

Fig. 5

Antimicrobial assessment of nanofiber mats against PAO1 and 10 Pseudomonas -resistant clinical isolates. The mats are composed of (A) PVA, (B) PVA + 8 mg/mL STG, (C) PVA + 9 mg/mL MER, (D) PVA +(1 STG: 1 MER), (E) PVA +(2 STG: 1 MER), and (F) PVA +(1 STG : 2 MER). Note: (A) PVA and (B) PVA + 8 mg/mL STG were tested against all strains; however, images are shown only for PAO1 and PR1

Fig. 6

Antimicrobial assessment of nanofiber mats over 3 months against PAO1 and PR1: (a) PVA + 9 mg/mL MER, (b) PVA +(1 STG: 1 MER), (c) PVA +(2 STG: 1 MER), (d) PVA +(1 STG : 2 MER)