Moreover, DSF-family signals showed a high level of potency in interference of the morphology transition of C. albicans[14, 17, 22], which is a critical

feature associated with the virulence of this pathogen. Given the fact that biofilm formation is related to antibiotic resistance [26], together with the role of DSF-family signals in regulation of bacterial biofilm formation and antibiotic resistance, click here we speculate that DSF-family signals may have a role in modulation of bacterial antibiotic susceptibility. In this study, we report that in the presence of DSF signal and its derivatives, some of which were identified as bacterial quorum sensing (QS) signals [13, 14, 18, 22],

the minimum inhibitory concentrations (MIC) of a few antibiotics against the bacterial pathogens were significantly reduced. Furthermore, we showed that supplementation of DSF signal could substantially enhance the antimicrobial activity of gentamicin and Opaganib reduce the cytotoxicity of B. cereus in an in vitro infection model. Our findings suggest the promising potentials of DSF and its structurally related molecules as putative antibiotic adjuvants for the control of bacterial infections. Results DSF and its structurally related molecules increase the antibiotic susceptibility of B. cereus Bacillus is a genus of Gram-positive, rod-shaped bacteria. They are ubiquitous in nature, and consisting Florfenicol of both free-living and pathogenic species. Bacillus bacteria produce oval endospores to endure a wide range of extreme environmental conditions, while keeping the capacity to return to vegetative growth [27]. This remarkable characteristics of the endospore-vegetative cell transition of Bacillus pathogens allows them to be utilized as biological

weapons [28, 29]. Interestingly, our preliminary results showed that this morphological transition between the vegetative cell and endospore of Bacillus species could be stopped by exogenous addition of DSF-family signals (Deng, unpublished data). This finding, together with the previous observations that DSF signals are involved in regulation of bacterial biofilm formation, antibiotic tolerance and fungal morphological transition [15, 22–24], we speculated that DSF-family signals may affect the bacterial antibiotic sensitivity of Bacillus cells. To test this hypothesis, we firstly chose B. cereus, which is a common human pathogen and causes foodborne illness such as nausea, vomiting and diarrhea [30], to assay the antibiotic susceptibility in the presence of DSF signal or its derivatives (Table 1).