Ultrastructure imaging of Pseudomonas aeruginosa lawn biofilms and eradication of the tobramycin-resistant variants under in vitro electroceutical treatment

Abstract

Electrochemically generated bactericidal compounds have been shown to eradicate bacterial lawn biofilms through electroceutical treatment. However, the ultrastructure of biofilms exposed to these species has not been studied. Moreover, it is unknown if the efficacy of electroceutical treatment extends to antibiotic-resistant variants that emerge in lawn biofilms after antibiotic treatment. In this report, the efficacy of the in vitro electroceutical treatment of Pseudomonas aeruginosa biofilms is demonstrated both at room temperature and in an incubator, with a ~4 log decrease (p < 0.01) in the biofilm viability observed over the anode at both conditions. The ultrastructure changes in the lawn biofilms imaged using transmission electron microscopy demonstrate significant bacterial cell damage over the anode after 24 h of electroceutical treatment. A mix of both damaged and undamaged cells was observed over the cathode. Finally, both eradication and prevention of the emergence of tobramycinresistant variants were demonstrated by combining antibiotic treatment with electroceutical treatment on the lawn biofilms.

Potential of Bacterial Cellulose Chemisorbed with Anti-Metabolites, 3-Bromopyruvate or Sertraline, to Fight against Helicobacter pylori Lawn Biofilm

“…Following this idea, we performed an additional, self-developed experimental setting [ 35 , 37 ], in which active compounds released from a BC carrier need to penetrate through liquid microbiological medium and then through 3 day-old, lawn biofilm H. pylori cells ( Figure 1 ). It is worth noting that bacterial cells tested in the current experiments were adhered to the agar surface and immersed in the nutrient medium [ 38 , 39 ], while an alternative model focuses on biofilms and cell aggregates formed at the air-liquid surface [ 49 ]. Such procedure may affect the different physiology of H. pylori cells, while it guarantees obtaining high cell biomass, which is difficult to obtain for H. pylori using classical methods.…”

“…Then, 10 mm 2 agar fragments were cut out from each well. Following this, 5 mm 2 fragments of CA+HB agar with a three-day lawn H. pylori biofilms were placed in the empty space of each well (the lawn biofilms growth was done according to Dusane et al (2019) and Lochab et al (2020) [ 38 , 39 ], with an incubation at 37 °C and microaerophilic atmosphere). After this stage, the wells were filled with approx.…”

Electroceutical treatment of infected chronic wounds in a dog and a cat

“…29,30 For cat wounds, a smaller PED (1 Â 2 cm) was used with the simplified electrode geometry (Figure 1D,E) to match previously reported in vitro bactericidal effects. 29,31 The laboratory fabricated PEDs needed to be secured to the wound for treatment and the electrodes require a moist environment for proper functioning. Therefore, for PED treatment, a hydrogel was first applied to the wound bed to ensure the PED electrodes were moistened when applied.…”

Salmonella Biofilm Formation, Chronic Infection, and Immunity Within the Intestine and Hepatobiliary Tract

“…While ubiquitous in soil and water and a common colonizer of animals and humans, P. aeruginosa rarely infects healthy individuals but can infect multiple body sites in the immunocompromised (Wu and Li, 2015). While P. aeruginosa may have the most notoriety for infecting CF patients, it is also consequential in ventilator-associate pneumonia (Bergmans and Bonten, 1999;Mulcahy et al, 2014), on orthopedic implants and joint replacement surgical sties (Mulcahy et al, 2014), catheters (Cole et al, 2014), and in severe soft tissue wounds (Lochab et al, 2020). Characteristic of chronic biofilm infections, P. aeruginosa infections are difficult to detect with clinical microbiology techniques (Costerton et al, 2003;Mulcahy et al, 2014) and are extremely recalcitrant to antibiotics and the host environment (Mulcahy et al, 2014;Lochab et al, 2020).…”

“…While P. aeruginosa may have the most notoriety for infecting CF patients, it is also consequential in ventilator-associate pneumonia (Bergmans and Bonten, 1999;Mulcahy et al, 2014), on orthopedic implants and joint replacement surgical sties (Mulcahy et al, 2014), catheters (Cole et al, 2014), and in severe soft tissue wounds (Lochab et al, 2020). Characteristic of chronic biofilm infections, P. aeruginosa infections are difficult to detect with clinical microbiology techniques (Costerton et al, 2003;Mulcahy et al, 2014) and are extremely recalcitrant to antibiotics and the host environment (Mulcahy et al, 2014;Lochab et al, 2020). In 2015, hospitalized cancer, CF, or burn wound patients with P. aeruginosa infection experienced a 50% mortality rate (Goḿez and Prince, 2007;Wu and Li, 2015) and the CDC reports that P. aeruginosa is the fourth-most isolated pathogen in hospitals, accounting for 10% of all nosocomial infections (Wu and Li, 2015).…”