Vitamin C in the Presence of Sub-Inhibitory Concentration of Aminoglycosides and Fluoroquinolones Alters Proteus mirabilis Biofilm Inhibitory Rate

Abstract

Vitamin C has antimicrobial activity and is often used as an oral supplement accompanying antibiotic treatment in urinary tract infections (UTI). Proteus mirabilis is the third common species responsible for UTIs that are mostly treated with fluoroquinolones or aminoglycosides. Treatment of the UTI caused by P. mirabilis is problematic due to the ability to form biofilm on the urinary catheters. The aim of the study was to evaluate the influence of ascorbic acid in combination with antibiotics on P. mirabilis abilities to form biofilm. The susceptibility of P. mirabilis reference strain ATCC® 29906™ and four clinical strains isolated from the urine samples of patients with urinary catheter were evaluated according to EUCAST recommendations. The influence of ascorbic acid (0.4 mg × mL−1) in combination with antibiotics on biofilm formation was evaluated spectrophotometrically. Aminoglycosides at sub-inhibitory concentrations more successfully limited biofilm formation by P. mirabilis strains without ascorbic acid addition. Inhibition rate differences at the lowest concentrations of gentamicin and amikacin were statistically significant (p ≤ 0.05). Ascorbic acid addition to the culture medium limited the inhibitory effect of fluoroquinolones, facilitating biofilm formation by P. mirabilis strains. The addition of ascorbic acid during aminoglycosides therapy may disturb treatment of urinary tract infections related to the presence of P. mirabilis biofilm.

Vitamin C Enhances the Antibacterial Activity of Honey against Planktonic and Biofilm-Embedded Bacteria

“…A variety of Vit C concentrations have been found in various honey samples, where the concentration of Vit C ranged from 0.34 to 75.9 mg/100 g of honey [19]. Although Vit C is a reducing agent capable of rapidly scavenging reactive oxygen species (ROS), surprisingly, it acts as a pro-oxidant antibacterial molecule [20][21][22] and it may alter the antimicrobial activity of some antibiotics [23,24]. There are two proposed mechanisms of action: (i) the transfer of Vit C into the bacterial cells, resulting in the formation of H 2 O 2 and, subsequently, ROS and (ii) the generation of lactate and acetic acids from Vit C [23,25].…”

The Role of Drug Repurposing in the Development of Novel Antimicrobial Drugs: Non-Antibiotic Pharmacological Agents as Quorum Sensing-Inhibitors

“…bithionol [91] zeaxantin [92] catecholamines [93] cranberry juice [94] celecoxib [69] resveratrol [95] coumarines [37,96] betulinic acid [97] chloroxazone [57] ajoene [98] daunorubicin [99] essential oils [71,94,100] diflunisal [101] finasteride [102] floxuridine [103] glyceryl-trinitrate [104] ibuprofen [105] ivermectin [68] local anesthetics [106,107] general anesthetics [106,107] metformin [108] miltefosine [109] niclosamide [110] parthenolide [111] toremifene [112] statins [65,66] streptozotocin [103] Vitamin A [113] Vitamin C [114] Vitamin D [113,115,116] Vitamin K [117] Some reports also suggested that various vitamins have potent adjuvant properties, enhancing the bactericidal activity of antibiotics (Table 2), and they also exert their own antibacterial activities in very high concentrations [103][104][105][106]…”

Non-antibiotic compounds affecting the growth of urinary pathogens during urine culture: a preliminary in vitro study

“…However, other studies also highlighted the antibacterial properties of acetyl-salicylic acid [46], allopurinole [47], various cardio-vascular medications [48], and several vitamins (A, C, D and K) [49][50][51][52]; this was not demonstrated in our in vitro settings.…”