Synergy of Plant Essential Oils in Antibiotic Therapy to Combat Klebsiella pneumoniae Infections

Abstract

Increased antibiotic resistance presents a health problem worldwide. The World Health Organization published a list of pathogens considered a priority for designing new treatments. Klebsiella pneumoniae (Kp) is a top-priority microorganism, highlighting the strains that produce carbapenemases. Developing new efficient therapies or complementing existing treatments is a priority, and essential oils (EOs) provide an alternative. EOs could act as antibiotic adjuvants and enhance antibiotic activity. Employing standard methodologies, the antibacterial activity of the EOs and their synergic effect with antibiotics were detected. A string test was used to identify the impact of the EOs over the hypermucoviscosity phenotype presented by Kp strains, and Gas Chromatography–Mass Spectrometry analysis identified EOs and the composition of EOs. The potential of EOs for designing synergistic therapies with antibiotics to combat the infection of KPC diseases was demonstrated. In addition, the alteration of the hypermucoviscosity phenotype was shown as the principal mechanism of a synergic action between EOs and antibiotics. The differential composition of the EOs lets us identify some molecules that will be analyzed. Synergic activity of EOs and antibiotics can provide a solid platform for combating multiresistant pathogens that represent a severe health sector problem, such as Kp infections.

Essential Oils from Southern Italian Aromatic Plants Synergize with Antibiotics against Escherichia coli, Pseudomonas aeruginosa and Enterococcus faecalis Cell Growth and Biofilm Formation

“…Therefore, these results represent further confirmation of the series of data in the literature which have highlighted the ability of EOs to enhance the effects of antibiotics in oil-, antibiotic-, and strain-specific manner. Similarly to those we analyzed, EOs containing carvacrol, eucalyptol, eugenol, and thymol have been demonstrated to exercise a synergistic effect in combination with antibiotics [17,18,28,41]. Findings observed in P. aeruginosa appear relevant if we consider that it is widely recognized as a prototype of a "multidrug-resistant pathogen" that is frequently associated with increased morbidity and mortality.…”

“…In recent years, various approaches have been developed, including the combination of antibiotics with EOs, to investigate the synergic effect of them, which could be more effective in counteracting bacterial resistance [13][14][15][16][17]. Romo-Castillo et al demonstrated the potential of EOs extracted from Rosmarinus officinalis, Thymus vulgaris, Mentha piperita, and Curcuma longa to combat K. pneumoniae by applying a synergic therapy for antibiotics [18]. The effects of Protium heptaphyllum EO (PHEO) alone and in combination with antibiotics against polymyxin-resistant K. pneumoniae isolates were also analyzed [19].…”

Plant-Origin Components: New Players to Combat Antibiotic Resistance in Klebsiella pneumoniae

“…Our group found that Thymus vulgaris, Mentha piperita, Rosmarinus officinalis, and Curcuma longa essential oils effectively against Kpn clinical strains, affecting the hypermucoviscosity phenotype. These findings indicate that essential oils are the best choice to combat mucus production and biofilm-forming strains [121]. However, more studies on essential oils are needed to investigate their safety profile, characterise their mechanism of action, optimise their dose, and observe possible adverse effects in human cells.…”

“…Our research group is focused on developing plant compounds that can be employed as synergic therapy with antibiotics (Figure 7). Our last report analysed the potential of essential oils (EOs) against Klebsiella pneumoniae infections [121]. We selected EOs with a zone diameter similar to antibiotics' standard breakpoints (>15 mm) and a synergic effect with antibiotics.…”