Efficacy of Photodynamic Inactivation against the Major Human Antibiotic-Resistant Uropathogens

Nadezhda Ignatova,Vadim Elagin,Vladislav Kamensky,Olga Streltsova,Ivan Budruev,Tatiana Ivanova,Artem Antonyan

doi:10.3390/photonics8110495

Abstract

Photodynamic inactivation (PDI) is considered to be an effective method of prevention of postoperative complications of urolithiasis. The present study shows a complex approach to assess the efficacy of PDI of drug resistant bacteria associated with renal calculi. Bacterial strains associated with renal calculi were isolated and identified using standard methods of bacteriological analysis and tested for drug resistance to 10 antibiotics by the disco-diffusion method. Uropathogenic bacterial strains present in 78.7 ± 5.2% of the infected samples from the total number of analyzed calculi. The most frequent representatives belonged to the genera Staphylococcus, Escherichia, and Enterococcus. All tested strains showed high antibiotic resistance. Representatives of the most common bacterial genera in the calculi were used as models for the selection of PD exposure modes. It was found that the maximum time of photosensitizer accumulation depends on the structure of the bacterial cell wall: 30 min for Gram-negative strains and 60 min for Gram-positive ones. Optimal modes of PD exposure to antibiotic-resistant uropathogenic microorganisms were selected: 50 µg/mL Fotoditazin and 150 mW laser power. The maximal bactericidal activity of PDI against uropathogenic microorganisms was shown for Enterococcus faecalis, and Staphylococcus aureus. The bacteriostatic effect was found against Escherichia coli and Proteus mirabilis.

Highlights

The frequent, prolonged, and uncontrolled use of antibiotics in the treatment of infections has resulted in an increasing number of bacterial strains resistant to a wide range of antibiotics [1]
It was found that renal calculi obtained during laparoscopic surgeries were contaminated in 78.7 ± 5.2% of cases (59 ± 6.2% by one strain and 19.7 ± 6.2% by 2 or more various strains) (Figure 3a)
66 species of microorganisms referred to various genera were isolated

Summary

Introduction

The frequent, prolonged, and uncontrolled use of antibiotics in the treatment of infections has resulted in an increasing number of bacterial strains resistant to a wide range of antibiotics [1]. The antibiotic resistant bacteria such as Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species cause the majority of hospital infections with high mortality of patients [2]. Antibiotic resistant pathogens are of great significance in the case of infected urinary stones. Urolithiasis is well known to be a widespread disease of the urinary system in middleage people. According to the annual costs of diagnosis, treatment and hospitalization, it ranks second among all urinary tract infections [3]. The increase in urolithiasis rate of more than 37% was reported over the last 20 years for some areas [4]. Urologists are especially challenged by stones with infections, which comprise ~15% of kidney stones [5]

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