Effects of Combined Treatment with Ambroxol and Ciprofloxacin on Catheter-Associated <b><i>Pseudomonas aeruginosa</i></b> Biofilms in a Rat Model

Abstract

Background:Pseudomonas aeruginosa is an opportunistic pathogen that causes potentially devastating infections in immunocompromised patients. These infections are particularly difficult to treat if a biofilm forms, which is likely if foreign bodies are present. Objective: This study aimed to investigate the effect of ambroxol combined with ciprofloxacin on P. aeruginosa biofilm in a rat model. Methods: A rat model of acute lung infection was created by endotracheal (ET) intubation with a tube covered with a P. aeruginosa biofilm. The rats were treated with ciprofloxacin alone, ambroxol alone, or a combination of both for 7 days. The microstructure of the biofilm on the tube was assessed by scanning electron microscopy (SEM). The numbers of bacterial colonies in the lungs and on the ET tube were measured on agar plates. Pathological changes in the lungs were observed with hematoxylin and eosin staining. Results: Changes in the microstructure of the biofilm after combined treatment were demonstrated by SEM. Ambroxol combined with ciprofloxacin significantly reduced the number of bacteria in the lungs and ET tube compared to the single treatments (p < 0.05). The pathological changes in the lungs were also mildest after the combined treatment. Conclusion: The combination treatment of ambroxol with ciprofloxacin has a high ability to eradicate P. aeruginosa biofilms in vivo. These initial results provide the basis of a new strategy for the treatment of P. aeruginosa infections.

Synergy of ambroxol with vancomycin in elimination of catheter-related Staphylococcus epidermidis biofilm in vitro and in vivo

“…Second, ambroxol can promote the permeability of vancomycin through S. epidermidis biofilms. It has been reported that ambroxol promotes the permeability of ciprofloxacin through P. aeruginosa biofilms [15]. Conventionally, the antimicrobials are only able to diffuse through the biofilm shallowly and kill bacteria located shallow in the biofilms [31].…”

“…Divided catheter segments were fixed in 2% glutaraldehyde solution as described in previous studies [15]. Following dehydration, catheters were coated with platinum-palladium and viewed under a JSM-35C scanning electron microscope (JEOL, Tokyo, Japan).…”

“…Recently, it was observed that ambroxol can damage the structure of mucoid Pseudomonas aeruginosa biofilms in vitro and attenuate the lung damage caused by biofilm-associated infection in vivo [13,14]. Moreover, it enhanced the ability of ciprofloxacin to eradicate P. aeruginosa biofilms in a ventilator-associated pneumonia (VAP) rat model [15]. However, the role of ambroxol against S. epidermidis biofilm in catheterrelated infections remains unknown.…”

Does Streptococcus mitis, a neonatal oropharyngeal bacterium, influence the pathogenicity of Pseudomonas aeruginosa?

“…Ethanol was added to dissolve the crystal violet, and the absorbance was measured at 570 nm. Meanwhile, bacterial adhesion was also observed by light microscopy (Nikon, Japan) and a plate counting method [10]. For the plate counting method, briefly, 24-well plates were washed 3 times using sterile PBS, and 1 ml PBS was added.…”

“…Briefly, 96-well plates were washed 3 times using sterile PBS, and 100 ml of BHI medium was added. Then, the plate was sealed with parafilm and agitated for 30 min with an ultrasonotor (1 MHz) [10], and 10 ml CCK-8 was added. After 4 h of incubation, the absorbance at 450 nm was measured.…”