Antibacterial and Antibiotic Resistance Modifying Effect of Bioactive Plant Extracts on Methicillin-Resistant Staphylococcus epidermidis

The crude extracts of plants from Asteraceae and Lamiaceae family and essential oils from Salvia officinalis and Salvia sclarea were studied for their antibacterial as well as antibiotic resistance modifying activity. Using disc diffusion and broth microdilution assays we determined higher antibacterial effect of three Salvia spp. and by evaluating the leakage of 260 nm absorbing material we detected effect of extracts and, namely, of essential oils on the disruption of cytoplasmic membrane. The evaluation of in vitro interactions between plant extracts and oxacillin described in terms of fractional inhibitory concentration (FIC) indices revealed synergistic or additive effects of plant extracts and clearly synergistic effects of essential oil from Salvia officinalis with oxacillin in methicillin-resistant Staphylococcus epidermidis

In Vitro Antibacterial and Antibiotic Resistance Modifying Effect of Bioactive Plant Extracts on Methicillin-Resistant Staphylococcus epidermidis

The crude extracts of plants from Asteraceae and Lamiaceae family and essential oils from Salvia officinalis and Salvia sclarea were studied for their antibacterial as well as antibiotic resistance modifying activity. Using disc diffusion and broth microdilution assays we determined higher antibacterial effect of three Salvia spp. and by evaluating the leakage of 260 nm absorbing material we detected effect of extracts and, namely, of essential oils on the disruption of cytoplasmic membrane. The evaluation of in vitro interactions between plant extracts and oxacillin described in terms of fractional inhibitory concentration (FIC) indices revealed synergistic or additive effects of plant extracts and clearly synergistic effects of essential oil from Salvia officinalis with oxacillin in methicillin-resistant Staphylococcus epidermidis

Probiotic potential and safety properties of Lactobacillus plantarum from Slovak Bryndza cheese

One hundred and twenty-five acid-resistant presumptive lactobacilli were isolated from Slovak Bryndza cheese and screened for their antimicrobial activity against eight bacterial pathogens using spot agar assay. Out of twenty-six Lactobacillus strains with strong inhibition activity, twenty were identified as Lactobacillus plantarum and six as Lactobacillus fermentum. The most active eleven L. plantarum isolates were further characterized in vitro for some probiotic and safety properties. Only three isolates K10, K21, and ZS07 showed the ability to grow over 50% in the presence of 0.3% bile. Strong deconjugation efficiency was determined for CK06 and K21. The highest -galactosidase activity was shown in isolates ZS11, B01, CK06, and ZS07. Only three of the strains had the ability to produce tyramine: CK06, LM1, and ZS11. Strains K09, K21, ZS11, and ZS15 were susceptible to all tested antibiotics. Analysis of the results confirmed the L. plantarum isolates ZS07 and K21 as the most suitable for probiotic use, due to their desirable probiotic and safety characteristics

Modulation of mecA Gene Expression by Essential Oil from Salvia sclarea and Synergism with Oxacillin in Methicillin Resistant Staphylococcus epidermidis Carrying Different Types of Staphylococcal Chromosomal Cassette mec

The essential oil (EO) from Salvia sclarea was shown to increase the susceptibility of methicillin resistant Staphylococcus epidermidis (MRSE) isolates to oxacillin. The purpose of this study was to investigate the effect of EO from S. sclarea on expression of mecA gene of MRSE carrying different types of staphylococcal chromosomal cassette (SCCmec) and to evaluate potential synergistic effect of EO with oxacillin. Using real-time PCR we found that EO alone inhibited the expression of the resistant genes mecA, mecR1, and mecI and blaZ, blaR1, and blaI. The use of the combination of EO with oxacillin resulted in significantly inhibited expression of mecA gene in all tested strains with different types of SCCmec. Using time-kill assay and checkerboard assay we confirmed synergistic effect of EO from S. sclarea and oxacillin in MRSE

Probiotic Potential and Safety Properties of Lactobacillus plantarum from Slovak Bryndza Cheese

One hundred and twenty-five acid-resistant presumptive lactobacilli were isolated from Slovak Bryndza cheese and screened for their antimicrobial activity against eight bacterial pathogens using spot agar assay. Out of twenty-six Lactobacillus strains with strong inhibition activity, twenty were identified as Lactobacillus plantarum and six as Lactobacillus fermentum. The most active eleven L. plantarum isolates were further characterized in vitro for some probiotic and safety properties. Only three isolates K10, K21, and ZS07 showed the ability to grow over 50% in the presence of 0.3% bile. Strong deconjugation efficiency was determined for CK06 and K21. The highest β-galactosidase activity was shown in isolates ZS11, B01, CK06, and ZS07. Only three of the strains had the ability to produce tyramine: CK06, LM1, and ZS11. Strains K09, K21, ZS11, and ZS15 were susceptible to all tested antibiotics. Analysis of the results confirmed the L. plantarum isolates ZS07 and K21 as the most suitable for probiotic use, due to their desirable probiotic and safety characteristics

Modulation of mecA Gene Expression by Essential Oil from Salvia sclarea and Synergism with Oxacillin in Methicillin Resistant Staphylococcus epidermidis Carrying Different Types of Staphylococcal Chromosomal Cassette mec

The essential oil (EO) from Salvia sclarea was shown to increase the susceptibility of methicillin resistant Staphylococcus epidermidis (MRSE) isolates to oxacillin. The purpose of this study was to investigate the effect of EO from S. sclarea on expression of mecA gene of MRSE carrying different types of staphylococcal chromosomal cassette (SCCmec) and to evaluate potential synergistic effect of EO with oxacillin. Using real-time PCR we found that EO alone inhibited the expression of the resistant genes mecA, mecR1, and mecI and blaZ, blaR1, and blaI. The use of the combination of EO with oxacillin resulted in significantly inhibited expression of mecA gene in all tested strains with different types of SCCmec. Using time-kill assay and checkerboard assay we confirmed synergistic effect of EO from S. sclarea and oxacillin in MRSE

Complex Analysis of Vanillin and Syringic Acid as Natural Antimicrobial Agents against Staphylococcus epidermidis Biofilms

The presence of Staphylococcus epidermidis biofilms on medical devices is a major cause of nosocomial diseases and infections. Extensive research is directed at inhibiting the formation and maturation of such biofilms. Natural plant-derived phenolic compounds have promising antimicrobial effects against drug-resistant bacteria. The anti-biofilm activity of two selected phenolic compounds (vanillin and syringic acid) was tested against three biofilm-forming methicillin-resistant S. epidermidis strains with different genotypes. Resazurin assay combining crystal violet staining and confocal microscopy was used for biofilm and extracellular polymer substance (EPS) inhibition tests. Effects on EPS compounds such as proteins, extracellular DNA, and polysaccharides were also examined. Combined with quantitative real-time PCR of selected agr quorum-sensing systems and biofilm genetic determinants, our complex analysis of vanillin and syringic acid showed similar biofilm and EPS inhibition effects on S. epidermidis strains, reducing biofilm formation up to 80% and EPS up to 55%, depending on the genotype of the tested strain. Natural antimicrobial agents are thus potentially useful inhibitors of biofilms

Role of RNAIII in Resistance to Antibiotics and Antimicrobial Agents in <i>Staphylococcus epidermidis</i> Biofilms

Staphylococcus epidermidis is a known opportunistic pathogen and is one of the leading causes of chronic biofilm-associated infections. Biofilm formation is considered as a main strategy to resist antibiotic treatment and help bacteria escape from the human immune system. Understanding the complex mechanisms in biofilm formation can help find new ways to treat resistant strains and lower the prevalence of nosocomial infections. In order to examine the role of RNAIII regulated by the agr quorum sensing system and to what extent it influences biofilm resistance to antimicrobial agents, deletion mutant S. epidermidis RP62a-ΔRNAIII deficient in repressor domains with a re-maining functional hld gene was created. A deletion strain was used to examine the influence of oxacillin in combination with vanillin on biofilm resistance and cell survival was determined. Utilizing real-time qPCR, confocal laser scanning microscopy (CLSM), and crystal violet staining analyses, we found that the RNAIII-independent controlled phenol soluble modulins (PSMs) and RNAIII effector molecule have a significant role in biofilm resistance to antibiotics and phenolic compounds, and it protects the integrity of biofilms. Moreover, a combination of antibiotic and antimicrobial agents can induce methicillin-resistant S. epidermidis biofilm formation and can lead to exceedingly difficult medical treatment