Effect of Cigarette and E-Cigarette Smoke Condensates on Candida albicans Biofilm Formation and Gene Expression.

Smoking triggers environmental changes in the oral cavity and increases the risk of mucosal infections caused by Candida albicans such as oral candidiasis. While cigarette smoke has a significant impact on C. albicans, how e-cigarettes affect this oral pathogen is less clear. Here, we investigated the effect of cigarette and e-cigarette smoke condensates (CSC and ECSC) on C. albicans growth, biofilm formation, and gene expression. Whereas pure nicotine (N) at the minimum inhibitory concentration (MIC, 4 mg/mL) prevented C. albicans growth, enhanced biofilm formation was observed at 0.1 mg/mL. In contrast, at this nicotine sub-MIC (0.1 mg/mL) concentration, CSC and ECSC had no significant effect on C. albicans biofilm formation. Additionally, N, CSC, and ECSC increased the expression of HWP1 and SAP2 genes. The ECSC group exhibited elevated expression levels of the EAP1 and ALS3 genes, compared to the nicotine-free ECSC (-) control. Moreover, our in vitro study illustrated that the antifungal drugs, fluconazole and amphotericin B, alleviated the effect of nicotine on C. albicans gene expression. Overall, the results of the study indicated nicotine from different sources may affect the pathogenic characteristics of C. albicans, including hyphal growth, biofilm formation, and particularly the expression of virulence-related genes.

Oral colonization of Candida albicans and Streptococcus mutans in children with or without fixed orthodontic appliances: A pilot study.

BACKGROUND/PURPOSE: Adolescents undergoing fixed orthodontic therapy have an increased risk of oral diseases due to additional plaque accumulation sites. However, the effect of fixed orthodontics appliances (FOAs) on the colonization of Candida albicans (Ca) and Streptococcus mutans (Sm), two synergistic oral pathogens, is largely unknown and was, therefore, the primary objective of this pilot investigation. MATERIAL AND METHODS: Sixteen children aged 10-15 years were enrolled, nine in the FOA and seven in the control groups. Saliva and occlusal plaque were collected, and the Ca and Sm levels were quantified with a quantitative real-time polymerase chain reaction (qPCR) assay. RESULTS: A trend of higher Ca levels was observed in the saliva and occlusal plaque of the FOA group, while the control group contained higher levels of Sm. Furthermore, for Sm levels, a positive correlation between saliva and occlusal plaque was shown in both the FOA and control groups; in contrast, Ca levels were negatively correlated between these samples only in the FOA group. Between Ca and Sm, a positive correlation was observed in saliva and occlusal plaque in the control group; however, this relationship was disrupted in the FOA group. CONCLUSION: Our preliminary study demonstrated that the presence of FOAs disturbs the colonization of Ca and Sm within the oral cavity. This perturbation might increase orthodontic patients' risk for Ca- and Sm-related diseases.

Omics and interspecies interaction.

Interspecies interactions are key determinants in biofilm behavior, ecology, and architecture. The cellular responses of microorganisms to each other at transcriptional, proteomic, and metabolomic levels ultimately determine the characteristics of biofilm and the corresponding implications for health and disease. Advances in omics technologies have revolutionized our understanding of microbial community composition and their activities as a whole. Large-scale analyses of the complex interaction between the many microbial species residing within a biofilm, however, are currently still hampered by technical and bioinformatics challenges. Thus, studies of interspecies interactions have largely focused on the transcriptional and proteomic changes that occur during the contact of a few prominent species, such as Porphyromonas gingivalis, Streptococcus mutans, Candida albicans, and a few others, with selected partner species. Expansion of available tools is necessary to grow the revealing, albeit limited, insight these studies have provided into a profound understanding of the nature of individual microbial responses to the presence of others. This will allow us to answer important questions including: Which intermicrobial interactions orchestrate the myriad of cooperative, synergistic, antagonistic, manipulative, and other types of relationships and activities in the complex biofilm environment, and what are the implications for oral health and disease?

Activity of Hospital Disinfectants against Vegetative Cells and Spores of Clostridioides difficile Embedded in Biofilms.

Clostridioides difficile spores can survive in the environment in either mono- or mixed-species biofilms. However, no previous studies have investigated chemical disinfection of C. difficile spores embedded in biofilms. Thus, the purpose of this study was to assess the in vitro effectiveness of hospital disinfectants against C. difficile spores embedded within biofilms. Five unique C. difficile strains embedded in three different biofilm types grown for 72 or 120 h were exposed to seven different hospital disinfectants. C. difficile abundance [as log(number of CFU/milliliter)] was calculated after manufacturer-determined contact times along with biofilm biomass and microscopy. The primary analysis compared differences between C. difficile vegetative cell and spore counts as well as amounts of biomass after exposure to disinfectants. C. difficile vegetative cells and spores were recovered from biofilms regardless of the type of biofilm growth or biofilm growth time. No disinfectant was able to completely eliminate C. difficile from the biofilms. Overall, Clorox, ortho-phthalaldehyde (OPA), and Virex were most effective at killing C. difficile spores regardless of biofilm age, ribotype, or wash conditions (whether biofilms are washed or unwashed) (P = 0.001, each). Clorox and OPA were also effective at killing total vegetative cell growth (P = 0.001, each), but Virex was found to be ineffective against vegetative cell growth in biofilms (P = 0.77). Clorox and Virex were most effective in reducing biomass, followed by Nixall, OPA, and Vital Oxide. No disinfectant was able to completely eliminate C. difficile embedded within biofilms although differences among disinfectants were noted. Future research will be required to determine methods to eradicate this persister reservoir.

Design and synthesis of mucoadhesive nanogel containing farnesol: investigation of the effect on HWP1, SAP6 and Rim101 genes expression of Candida albicans in vitro.

The evolution of drug resistance of Candida species to conventional antifungal agents has been a major medical challenge worldwide; attempt to use the potential antifungal agents with appropriate therapy efficacy and minimum effects is considerably growing. This study was conducted to evaluate the use of nanogel as a nanocarrier for pharmaceutical application of farnesol. The nanogels were synthetized using alginate (AL) and chitosan (CS) polymers containing 300 µM of farnesol in the nano-range 42-70 nm size. In vitro release studies indicated that release of farnesol from CS and AL nanogels was as 58% and 37%, respectively. Chitosan nanogel showed more in inhibitory zone as compared to AL nanogel (9 mm). Also, cytotoxicity assay showed no significant difference between control and treatment groups (p>.05). Finally, the effect of nanogels on genes expression of HWP1, SAP6 and Rim101 in Candida albicans ATCC10231 was assessed using real-time polymerase chain reaction (PCR). Expression of HWP1 and SAP6 genes in C. albicans treated with CS nanogel was significantly decreased (p<.01). In general, the obtained finding showed that, CS nanogel contains farnesol with proper antifungal activity and as a new approach used in pharmaceutical applications against C. albicans; however, more studies in vitro and in vivo are needed in the future.