Antimicrobial activity of plant extracts against oral pathogens. Detection of cellular structural changes by FT-IR.

Periodontal diseases and dental caries are common oral disorders in human population with a multifactorial etiology closely related with the development of dental plaque. The latter is composed of native oral microbiota and it is accumulated on teeth surfaces. Several antiseptic agents are used widely to inhibit bacterial growth [1,2]. However, these substances have adverse effects. In the current study, six plants extracts namely, chamomile, dittany, lemon balm, rosemary, saffron and sage, were tested as potential natural antimicrobial agents. The antimicrobial activity of plants extracts was studied towards Gram-positive strains belonging to Streptococcus species related to the oral health. Fourier transform infrared spectroscopy (FT-IR) was applied in order to evaluate the changes in the cellular composition of target bacterial cells after their exposure to extracts of both plants

Instrumental Analysis of bacterial cells growth under incubation with Crocus sativus L. extracts using FT-IR spectroscopy

Foodborne illness is a threat to public health and challenge for food industry. Very young children, pregnant women, people with compromised immune systems and the elderly are at the most risk. Foodborne illness also known as food poisoning usually arises from improper handling, preparation, or food storage and is associated with microbial pathogens. Bacteria are a common cause of foodborne illness and especially Salmonella and Escherichia coli. At present food industry uses chemical additives in several processes in order to prevent bacterial growth and extend the shelf life of foods. However, these substances have adverse effects. In the current study, Crocus sativus L. extracts were tested as potential natural antimicrobial agents. The antimicrobial activity of plants extracts was studied towards Gram-negative strains belonging to the above species. Fourier transform infrared spectroscopy (FT-IR) was applied in order to evaluate the changes in the cellular composition of target bacterial cells after their exposure to extracts

Antimicrobial activity of Melissa officinalis L. and Crocus sativus L. against oral pathogens: Detection of cellular structural changes by FT-IR.

Periodontal diseases and dental caries are common oral disorders in human population with a multifactorial etiology closely related with the development of dental plaque. The latter is composed of native oral microbiota and it is accumulated on teeth surfaces. Several antiseptic agents are used widely to inhibit bacterial growth [1,2]. However, these substances have adverse effects. In the current study, Melissa officinalis L. and Crocus sativus L. extracts were tested as potential natural antimicrobial agents. The antimicrobial activity of plants extracts was studied towards Gram-positive strains belonging to Streptococcus species related to the oral health. Fourier transform infrared spectroscopy (FT-IR) was applied in order to evaluate the changes in the cellular composition of target bacterial cells after their exposure to extracts of both plants

Comparative study of biological activities of Crocus sativus L. extracts and Lamiaceae plants’ extracts

In the current study, different extracts of Origanum dictamnus L. leaves (dittany), Melissa officinalis L. leaves (lemon balm) and Crocus sativus L. stigmas (saffron) were tested as potential natural antoxidant and antimicrobial agents

Comparative genomics among members of the Streptococcus bovis/Streptococcus equinus complex

Background: Today, only one streptococcal species, i.e. Streptococcus thermophilus is recognized as food-grade. Interestingly, other streptococci like Streptococcus macedonicus and Streptococcus infantarius belonging to the Streptococcus bovis/Streptococcus equinus complex (SBSEC) are also found in food matrices. However, these species are phylogenetically related to Streptococcus gallolyticus and Streptococcus pasteurianus that have been linked to endocarditis, bacteremia and colon cancer. Objectives: To compare the available genomes of the members of the SBSEC in order to shed light onto their evolution and phylogenetic relation and to assess in silico their pathogenic potential. Methods: Comparative genomics analysis including full chromosome and CDS alignments, whole genome phylogeny and evaluation of gene content (e.g. core genome, singletons, etc.) was performed with appropriate bioinformatics tools. Conclusions: Despite the fact that the four species of the SBSEC were found tightly related based on whole genome phylogeny, there were two different patterns of evolution among them. Streptococcus pasteurianus, S. macedonicus and S. infantarius seem to have undergone a reductive evolution process that resulted in significantly diminished genome sizes and increased percentages of potential pseudogenes when compared to S. gallolyticus. In addition, S. pasteurianus, S. macedonicus and S. infantarius seem to have lost several genes previously linked to the ability of S. gallolyticus to survive in the gastrointestinal tract of herbivores and to its pathogenicity. Our findings indicate differences in the ecological niche and the pathogenic potential among the four species

Comparative genomics of Streptococcus macedonicus ACA-DC 198 against related species within the Streptococcus bovis/Streptococcus equinus complex

Apart from Streptococcus thermophilus other streptococci that can be found growing in milk belong to the Streptococcus bovis/Streptococcus equinus complex (SBSEC). Interestingly, Streptococcus macedonicus, which is a member of SBSEC, has been suggested to be adapted to milk and to be nonpathogenic. However, the species is phylogenetically related to Streptococcus gallolyticus and Streptococcus pasteurianus (formerly known as S. bovis biotypes I and II.2, respectively), which in turn are considered pathogenic, since they have been implicated in endocarditis and colon cancer in humans. Comparative analysis of the S. macedonicus genome with the complete genomes of its related streptococci (including that of S. infantarius, which is also a dairy isolate) indicated that a significant portion of the genomic organization has been conserved overall. Following a gene presence/absence strategy, we determined that S. macedonicus shows a reduced capacity to reside in the gastrointestinal tract of ruminants when compared to S. gallolyticus since it misses important genes for metabolizing complex carbohydrates of plant origin and for detoxifying this environment. S. macedonicus also lacks several pathogenicity traits found in S. gallolyticus. For example from the three pilus gene clusters (pil1, pil2, pil3), which may mediate the binding of S. gallolyticus to the extracellular matrix, S. macedonicus carries only one (i.e. the pil3). Gene gain events are also evident in the S. macedonicus genome sometimes originating from dairy bacteria, like the acquisition of the lactococcal plasmid pSMA198. Functional analysis of the S. macedonicus genome is necessary to further assess its pathogenic and technological potential