Down-Regulation of fliL Gene Expression by Ag Nanoparticles and TiO2 Nanoparticles in Pragmatic Clinical Isolates of Proteus mirabilis and Proteus vulgaris from Urinary Tract Infection

Abstract

Ten isolates belonging to Proteus spp. were collected and obtained from Department of Biology, College of Science, the University of Baghdad. The diagnosis was done by polymerase chain reaction (PCR) technique using 16S rRNA gene and urease C gene. All isolates (100%) were sensitive to meropenem, imipenem, ciprofloxacin, gentamycin, amoxicillin, clavulanic acid and levofloxacin. These isolates also showed 60% sensitivity to cefixime and nitrofurantoin. However, both species of P. mirabilis and P. vulgaris showed the lowest sensitivity when treated with tetracycline (60%) and amikacin (20%). Cephalothin had a variable effect on the species under study as P. mirabilis isolates were 100% sensitive in comparison with the 80% sensitivity of P. vulgaris isolates. The antibacterial activities of Ag and TiO 2 nanoparticles (NPs) were investigated. The minimum inhibitory concentration (MIC) value of Ag NPs against both species isolates was 10 mg/mL, while the MIC value of TiO 2 NPs was 14 mg/mL against P. mirabilis and 15 mg/mL against P. vulgaris isolates. P. mirabilis isolates showed larger swarming diameter than P. vulgaris, but this motility phenomenon of P. vulgaris was arrested rapidly after incubation with sub-MIC of TiO 2 NPs and Ag NPs comparatively with control. All isolates showed shifting to down-regulation in the fliL gene expression under the effect of the NPs using TiO 2 NPs and Ag NPs. In conclusion, down-regulation of the fliL gene expression is directly linked to the inhibition of swarming movement of Proteus species. We encourage using these inhibitors (after tests to ensure minimal toxicity to human) in combination with antibiotics to ensure bactericidal /bacteriostatic effect to treat Proteus infections.

Green Synthesis of Silver Nanoparticles using Aqueous Leaf Extract of Ocimum basilicum and Investigation of their Potential Antibacterial Activity

“…40 There are many researches which reported down regulation of some virulence factors caused by direct impact of SNPs and TiO2 nanoparticles against pathogenic bacteria. 41…”

The impact some of nutrients on swarming phenomenon and detection the responsible gene RsbA in clinical isolates of Proteus mirabilis

“…P-Nitrophenylglycerol (PNPG) also can inhibit not only swarming but also the ability of P. mirabilis to express other virulence factors such as urease and hemolysin which coupled to swarming and prevent its invasion to human urothelial cells (Allison et al, 1994;Liaw et al, 2000). Ag Nanoparticles and TiO2 Nanoparticles lead to down regulation in liL Gene Expression that related with swarming movement in Proteus spp (Saleh et al, 2019). There are several other theories that have been suggested to explain the mechanism of swarming of bacteria.…”

Nanomaterials for the Diagnosis and Treatment of Urinary Tract Infections

“…Saleh et al [ 126 ] formulated and investigated the mechanisms of antimicrobial action of two different types of metallic NPs, i.e., Ag-based and titanium dioxide-based NPs, against Proteus vulgaris and Proteus mirabilis , reporting that both kinds of NPs inhibited the microbial species via downregulation of fliL gene expression directly associated with blockade of the movement of the Proteus species. Similarly, Das et al [ 127 ] created Ag NPs loaded with the extract of Oxalis corniculata and observed that compared with pure extract, extract-based Ag NPs exhibited significantly higher antimicrobial activities against both Gram-positive and Gram-negative bacterial strains, the leading cause of UTIs.…”