Project description:To explain enhanced biofilm formation and increased dissemination of S. epidermidis in mixed-species biofilms, microarrays were used to explore differential gene expression of S. epidermidis in mixed-species biofilms. One sample from single species biofilm (S1) and mixed-species biofilm (SC2) were excluded from analyses for outliers. We observed upregulation (2.7%) and down regulation (6%) of S. epidermidis genes in mixed-species biofilms. Autolysis repressors lrgA and lrgB were down regulated 36-fold and 27-fold respectively and was associated with increased eDNA possibly due to enhanced autolysis in mixed-species biofilms. These data suggest that bacterial autolysis and release of eDNA in the biofilm matrix may be responsible for enhancement and dissemination of mixed-species biofilms of S. epidermidis and C. albicans.
Project description:To explain enhanced biofilm formation and increased dissemination of S. epidermidis in mixed-species biofilms, microarrays were used to explore differential gene expression of S. epidermidis in mixed-species biofilms. One sample from single species biofilm (S1) and mixed-species biofilm (SC2) were excluded from analyses for outliers. We observed upregulation (2.7%) and down regulation (6%) of S. epidermidis genes in mixed-species biofilms. Autolysis repressors lrgA and lrgB were down regulated 36-fold and 27-fold respectively and was associated with increased eDNA possibly due to enhanced autolysis in mixed-species biofilms. These data suggest that bacterial autolysis and release of eDNA in the biofilm matrix may be responsible for enhancement and dissemination of mixed-species biofilms of S. epidermidis and C. albicans. Staphylococcal gene expression in mixed-species biofilms with Candida and in single species biofilms of S. epidermidis were analyzed. The experiment was repeated thrice on 3 different days (3 biological replicates each for single species biofilms of S. epidermidis and mixed-species biofilms). Only 2 biological replicates were analyzed and one biological replicate was not analyzed (S1 and SC1 - raw data files are provided on the Series record). Single species biofilms of S. epidermidis (strain 1457) and C. albicans (strain 32354) and mixed-species biofilms were formed on 6-well tissue culture plates. Five ml of organism suspensions (O.D. 0.3, S. epidermidis 107 CFU/ml or C. albicans 105 CFU/ml) or 2.5 ml each for mixed-species biofilms for 24 hr. RNA was harvested from single species and mixed-species biofilms.
Project description:Candida albicans, a major opportunistic fungal pathogen is frequently found together with Streptococcus mutans in dental biofilms associated with severe childhood tooth-decay, a prevalent pediatric oral disease. Previous studies have demonstrated that S. mutans and C. albicans synergizes virulence of plaque-biofilms in vivo. However, the nature of this bacterial-fungal relationship in this cross-kingdom biofilm remains largely uncharacterized. Using iTRAQ based quantitative proteomics, we found that proteins associated with carbohydrate metabolism such as alpha-1,4 glucan phosphorylase, Hexokinase-2, Isocitrate lyase and malate synthase were significantly upregulated in C. albicans in the mixed-species biofilms (P<0.05). C. albicans proteins associated with growth/morphogenesis such as pH-responsive protein-2, Fma1p and Hsp21 were also induced. Conversely, S. mutans proteins in the tricarboxylic acid cycle such as citrate synthase and in the pentose phosphate pathway such as Ribose-5-phosphate isomerase A as well as proteins associated with sugar transport systems were upregulated indicating enhanced carbohydrate metabolism. Interestingly mixed-species biofilm microenvironment had a lower pH than S. mutans single-species biofilms. This observation was supported by proteomics, wherein proteins associated with lactate and formate assimilation such as Glyoxalase and putative NADPH-dependent methylglyoxal reductase proteins were significantly upregulated in the mixed-species biofilms (P<0.05). Furthermore, we unexpectedly found that S. mutans derived glucosyltransferase B (GtfB), responsible for co-adhesion via glucans, can also contribute to C. albicans growth and carbohydrate metabolism by providing glucose and fructose from sucrose breakdown. These findings demonstrate synergistic bacterial-fungal interactions within mixed-species biofilms and a novel GtfB cross-feeding role. Taken together, quantitative proteomics provides new insights into this virulent cross-kingdom oral biofilm.
Project description:We performed comparative analysis of transcriptomes of S. mutans in single biofilms and in mixed-biofilms with A. actinomycetemcomitans. We also compared the transcriptomic profiles of A. actinomycetemcomitans in single biofilms and A. actinomycetemcomitans in mixed biofilms with S. mutans. Finally we looked at the changes in gene expression in both organisms in time.
Project description:Coexistence of polymicrobial organisms acted as biofilm communities has become more and more prominent that these interactions lead to an increased resistance against host immune responses and antimicrobial agents, especially bacterial-fungal interactions. Klebsiella pneumoniae and Candida albicans are one of the interesting candidates acted as interkingdom biofilms. K. pneumoniae and C. albicans (KP+CA) presented the interkingdom biofilms with synergistic interaction through molecular analysis and confocal fluorescent imaging with z-stack thickness in vitro experiments. Both of an acute pneumonia model and in vitro neutrophil responses demonstrated that K. pneumoniae infection performed the highest severity when compared to mixed K. pneumoniae and C. albicans and alone C. albicans infections through various biomarkers and the responsiveness of neutrophils. Consequently, this study indicated that polymicrobial with bacterial-Candida infection may less severe than single-bacterial infection.
Project description:The World Health Organization (WHO) had designated Candida auris as a critical public health threat due to its multidrug resistance to antifungal agents, high mortality rate, and its ability to cause nosocomial outbreaks. A matter of serious concern is that conventional antifungal monotherapies is frequently ineffective against biofilm-associated C. auris infection, highlighting the need for more effective strategies. Combination therapies have demonstrated improved efficacy and specificity, and may also slow the development of antifungal resistance. Therefore, this study aimed to evaluate the in vitro and in vivo efficacy of caspofungin (CAS) and posaconazole (POSA) in combination against sessile C. auris isolates from the South Asian clade and to characterize the associated transcriptomic responses. The CAS with POSA combination resulted in a significant reduction in median minimum inhibitory concentrations (4–32-fold for CAS and 8–64-fold for POSA) compared to monotherapies. Synergistic interactions were observed in all isolates tested, with fractional inhibitory concentration indices ranging from 0.078 to 0.31. In line with the in vitro findings, synergistic interactions were confirmed by in vivo experiments. The fungal kidney burden decreases were three log volumes in mice treated with combination of 1 mg/kg/day caspofungin and 1.5 mg/kg/day posaconazole. To investigate the gene expression changes in response to combination treatment, 612 genes showed increased expression and 465 genes were downregulated relative to the untreated control biofilms (fold change >1.5 or <–1.5). Notably, genes involved in biofilm dispersion, oxidative stress response, iron metabolism, and glycolysis were downregulated, whereas those associated with cell wall organization or biogenesis, osmotic stress response, calcium signaling, drug efflux, biofilm formation, and the biosynthesis of ergosterol and chitin were upregulated. These findings demonstrate the potent synergistic activity of CAS and POSA against C. auris biofilms and provide insight into C. auris antifungal therapeutic responses, thereby contributing to the development of more effective antifungal treatment strategies.
Project description:It is well known that bacteria often exist in naturally formed multispecies biofilms. Within these biofilms, interspecies interactions seem to play an important role in ecological processes. Little is known about the effects of interspecies interactions on gene expression in these multispecies biofilms. This study presents a comparative gene expression analysis of the Xanthomonas retroflexus transcriptome when grown in a single-species biofilm and in dual- and four-species consortia with Stenotrophomonas rhizophila, Microbacterium oxydans and Paenibacillus amylolyticus. The results revealed complex interdependent interaction patterns in the multispecies biofilms. Many of the regulated functions are related to interactions with the external environment and suggest a high phenotypic plasticity in response to coexistence with other species. Furthermore, the changed expression of genes involved in aromatic and branched chain amino acid biosynthesis suggests nutrient cross feeding as an contribution factor for the observed synergistic biofilm production when these four species coexists in a biofilm. X. retroflexus was cultivated in three replicates of single-species biofilm and combined with S. rhizophila, M. oxydans and P. amylolyticus in dual-species biofilms with three respective replicates. At last, we combined all four species in a multispecies biofilm with five replicates and conducted a RNA seq based comparative gene expression study utilizing the Illumina sequencing technology. Please note that the 'prodigal_all_new.txt' contains gene names (which are listed in the matrix_sum.txt) and their position in the genomes, which are included in the file 'all_contigs_500.fasta'.
Project description:It is well known that bacteria often exist in naturally formed multispecies biofilms. Within these biofilms, interspecies interactions seem to play an important role in ecological processes. Little is known about the effects of interspecies interactions on gene expression in these multispecies biofilms. This study presents a comparative gene expression analysis of the Xanthomonas retroflexus transcriptome when grown in a single-species biofilm and in dual- and four-species consortia with Stenotrophomonas rhizophila, Microbacterium oxydans and Paenibacillus amylolyticus. The results revealed complex interdependent interaction patterns in the multispecies biofilms. Many of the regulated functions are related to interactions with the external environment and suggest a high phenotypic plasticity in response to coexistence with other species. Furthermore, the changed expression of genes involved in aromatic and branched chain amino acid biosynthesis suggests nutrient cross feeding as an contribution factor for the observed synergistic biofilm production when these four species coexists in a biofilm.
Project description:Enterococcus faecalis is often co-isolated with Pseudomonas aeruginosa in mixed-species biofilm-associated infections of wounds and the urinary tract. As a defence strategy, the host innately restricts iron availability at infection sites. Despite their co-prevalence, the polymicrobial interactions of these two pathogens in low iron conditions, such as those found in the host, remains unexplored. Here we show that E. faecalis inhibits P. aeruginosa growth within macrocolony biofilms when iron is restricted. E. faecalis lactate dehydrogenase (ldh1) gives rise to L-lactate production during fermentative growth. We find that E. faecalis ldh1 mutant fails to inhibit P. aeruginosa growth. Additionally, we demonstrate that ldh1 expression is induced when iron is restricted, resulting in increased lactic acid exported and consequently, a reduction in pH. Together, our results suggest that E. faecalis synergistically impact P. aeruginosa growth negatively by decreasing environmental pH and L-lactate-mediated iron chelation. Overall, this study highlights that the microenvironment in which the infection occurs is important for understanding its pathophysiology.