Epidermidis Culture Research Articles

Exploring the anti-acne potential of Muntingia calabura L leaves against Staphylococcus epidermidis: In vitro and in silico perspective

Introduction: Muntingia calabura is a medicinal plant possessing antimicrobial properties against various bacteria. The purpose of this study was to examine in vitro and in silico activity of the ethyl acetate fraction of M. calabura leaves against the acne-causing commensal bacterium, Staphylococcus epidermidis. Methods: In this study, M. calabura leaves were extracted using ethanol and then further fractionated with ethyl acetate. The phytochemicals in the fraction were identified with thin layer chromatography (TLC). The activity of the fraction was then tested in S. epidermidis culture using the agar diffusion method. Additionally, the molecular docking of M. calabura phytochemicals constituents was simulated to teicoplanin-associated locus regulator (TcaR) of S. epidermidis. Results: The ethyl acetate fraction of M. calabura exhibited robust antibacterial activity against S. epidermidis culture, resulting in inhibition zones ranging from 5 to 10 mm. The fraction was found to contain flavonoids, saponins, and tannins as identified constituents. Further, during the molecular docking analysis, stigmasterol and 7-methoxyflavone demonstrated binding to TcaR with a lower and comparable binding energy of -7.40 and -6.19 kcal/mol, respectively, compared to the control drug, Penicillin-G (-6.40 kcal/mol). Conclusion: M. calabura has the potential to serve as a valuable source of active phytochemical compounds for addressing acne. Further studies are needed to isolate and evaluate each compound found in M. calabura individually against S. epidermidis.

Combined Effect of Ceftriaxon and Low-Frequency Ultrasound on the Viability of Staphylococcus epidermidis Cells in a Preformed Biofilm.

We studied the effect of low-frequency ultrasound on the antibacterial effect of ceftriaxone for Staphylococcus epidermidis strains isolated from biomaterial of patients with paraimplant inflammation after total replacement of large joints in the plankton and preformed biofilm forms. Low-frequency ultrasound had no antibacterial effect on the plankton S. epidermidis culture or bacterial cells in the biofilm, and combined exposure of the plankton culture to ultrasound and ceftriaxone did not modulate the antibacterial activity of ceftriaxone. The exposure of the biofilm formed by S. epidermidis strains to low-frequency ultrasound increased the sensitivity of bacterial cells to ceftriaxone in a concentration range of 5-200 μg/ml.

Alkaline stress inhibits the growth of Staphylococcus epidermidis by inducing TCA cycle-triggered ROS production

Many species of bacteria interact on the human skin to form a certain microbiome. Delftia acidovorans, a bacterium detected from human skin, inhibits the growth of S. epidermidis, a dominant bacterium of the human skin microbiota. Here, we show that ammonia secreted by D. acidovorans inhibits the growth of S. epidermidis by increasing the pH value of the medium. The pH value of D. acidovorans culture supernatant (CS) was higher than that of the medium without culture. The inhibitory activity of the D. acidovorans CS against the growth of S. epidermidis was decreased by neutralization with hydrochloric acid. Genes encoding enzymes related to ammonia production were found in the D. acidovorans genome. Moreover, the D. acidovorans CS contained a high concentration of ammonia. The addition of ammonia to S. epidermidis culture led to an increase in the reactive oxygen species (ROS) production and inhibited S. epidermidis growth. The addition of sodium hydroxide also led to an increase in the ROS production and inhibited S. epidermidis growth. The inhibitory activity of ammonia and sodium hydroxide against S. epidermidis growth was suppressed by malonic acid, an inhibitor of succinate dehydrogenase in the tricarboxylic acid (TCA) cycle, and N-acetyl-l-cysteine, a free radical scavenger. These findings suggest that D. acidovorans secretes ammonia and alkaline stress inhibits the growth of S. epidermidis by inducing TCA cycle-triggered ROS production.

Bioautographic identification of alder gray Alnus incana (L.) Moench. fruits and geranium meadow Geranium pratense L. rhizomes extracts active components exhibiting synergism of antimicrobial action with macrolides

Annotation. The increase in the number of isolated antibiotic-resistant strains of microorganisms stimulates the search for alternative sources of biologically active substances that have antibiotic-potentiating action and are able to block the mechanisms of bacterial resistance to antibiotics. The aim of the study was to carry out bioautographic identification of the active components of gray alder fruits, geranium meadow rhizomes extracts and preparation “Altan” (extractant 90% aqueous-ethanolic), which showed synergism of antimicrobial action with erythromycin against skin isolates of staphylococci with different MLS phenotypes. Paper chromatography, thin-layer chromatography and bioautography were performed. Statistical processing of results: UTHSCSA ImageTool 2.0, Microsoft Office Excel 2011 On bioautograms of gray alder fruits extract and Altan with subinhibitory concentrations of erythromycin inoculated with S. epidermidis culture (inductive MLS-resistance phenotype), near the start line, areas with clear edges of growth inhibition were detected indicating the presence of hydrolysable tannins. Bioautograms of geranium meadow rhizomes extract showed the presence of compounds with antibiotic-potentiating activity with pronounced hydrophobic properties, indicating the presence of essential oils. In the extracts of gray alder fruits and geranium meadow rhizomes, the active components with antibiotic-potentiating properties, namely hydrolysable tannins and essential oils, have been identified. The fruits of gray alder and geranium meadow rhizomes are recommended for their preclinical and in-depth pharmacological study.

Nasal commensal Staphylococcus epidermidis counteracts influenza virus.

Several microbes, including Staphylococcus epidermidis (S. epidermidis), a Gram-positive bacterium, live inside the human nasal cavity as commensals. The role of these nasal commensals in host innate immunity is largely unknown, although bacterial interference in the nasal microbiome may promote ecological competition between commensal bacteria and pathogenic species. We demonstrate here that S. epidermidis culture supernatants significantly suppressed the infectivity of various influenza viruses. Using high-performance liquid chromatography together with mass spectrometry, we identified a giant extracellular matrix-binding protein (Embp) as the major component involved in the anti-influenza effect of S. epidermidis. This anti-influenza activity was abrogated when Embp was mutated, confirming that Embp is essential for S. epidermidis activity against viral infection. We also showed that both S. epidermidis bacterial particles and Embp can directly bind to influenza virus. Furthermore, the injection of a recombinant Embp fragment containing a fibronectin-binding domain into embryonated eggs increased the survival rate of virus-infected chicken embryos. For an in vivo challenge study, prior Embp intranasal inoculation in chickens suppressed the viral titres and induced the expression of antiviral cytokines in the nasal tissues. These results suggest that S. epidermidis in the nasal cavity may serve as a defence mechanism against influenza virus infection.

Colonisation and interaction between S. epidermidis and S. aureus in the nose and throat of healthy adolescents.

Nasal colonisation with Staphylococcus aureus is a risk factor for developing nosocomial infections. It has been reported that S. epidermidis may produce a serine protease (Esp) inhibiting S. aureus biofilm formation and nasal colonisation. We aimed to analyse the correlation between S. aureus nasal and/or throat carriage and co-colonisation with S. epidermidis strains carrying esp, and the inhibitory effects of S. epidermidis culture supernatants on S. aureus biofilm formation and growth. We obtained 114 S. epidermidis isolates from the nose and 74 S. aureus from the nose and/or throat of healthy adolescents. S. aureus biofilm formation was analysed in a microtitre plate assay and the prevalence of ica, encoding biofilm formation, and esp was analysed with polymerase chain reaction (PCR). Inhibitory effects of S. epidermidis culture supernatants on S. aureus biofilm formation and growth was analysed in vitro. esp prevalence and expression was correlated with inhibitory effects. We detected biofilm formation in 45/74 (61%) S. aureus strains. The ica operon was more prevalent in isolates colonising the nose (12/15; 80%) versus isolates colonising the throat only (8/46; 17%). Almost two-thirds of S. epidermidis culture supernatants displayed high (≥ 50%) S. aureus biofilm inhibitory activity, without affecting growth. We found no correlation between the level of inhibitory activity and S. aureus colonisation. esp was ubiquitous in S. epidermidis, but esp expression did not correlate with biofilm inhibitory activity. S. epidermidis culture supernatants inhibit S. aureus biofilm formation, but do not affect bacterial growth. esp expression was not correlated with the inhibitory effects observed.

Inhibition of biofilm formation and lipase in Candida albicans by culture filtrate of Staphylococcus epidermidis in vitro

Background:Candida spp. are fourth most common cause of bloodstream infection in developed countries and emerging agents of fungemia in developing countries, with considerable attributable mortality. Candidemia is associated with the formation of complex, structured microbial communities called biofilms. Biofilm formation makes treatment difficult due to improper drug penetration and factors like high cost and adverse effects of antifungal drugs available. Hence, low-cost alternatives are urgently required to treat device-associated invasive candidiasis.Objectives:To study the effect of culture filtrate of Staphylococcus epidermidis on biofilm formation and lipase expression of Candida albicans in vitro.Materials and Methods:Yeast cells isolated from clinical samples were suspended to a turbidity of 106 in (a) Yeast extract-peptone-dextrose (YPD) broth and (b) culture filtrate, and 100 μl of each were dispensed in separate wells of microtiter plate. After repeated washing and reloading with respective liquid media, readings were taken spectrophotometrically. To check for lipase inhibition, yeasts were incubated overnight in YPD and filtrate and subcultured on media containing Tween-80 and CaCl2. Positive lipase activity was denoted by haziness around colonies.Results:Mean reading of C. albicans in YPD broth was 0.579 while the same when yeasts were suspended in S. epidermidis culture filtrate was 0.281 (P < 0.05 by Z-test of significance). Lipase of C. albicans was inhibited by culture filtrate. Filtrate was found to be nontoxic to human cell line.Conclusions:Culture filtrate of S. epidermidis can hence pave the way for development of new strategies to inhibit biofilm formation in device-associated candidemia.

Self-Assembled Poly(ethylene glycol)-co-Acrylic Acid Microgels to Inhibit Bacterial Colonization of Synthetic Surfaces

We explored the use of self-assembled microgels to inhibit the bacterial colonization of synthetic surfaces both by modulating surface cell adhesiveness at length scales comparable to bacterial dimensions (∼1 μm) and by locally storing/releasing an antimicrobial. Poly(ethylene glycol) [PEG] and poly(ethylene glycol)-co-acrylic acid [PEG-AA] microgels were synthesized by suspension photopolymerization. Consistent with macroscopic gels, a pH dependence of both zeta potential and hydrodynamic diameter was observed in AA-containing microgels but not in pure PEG microgels. The microgels were electrostatically deposited onto poly(l-lysine) (PLL) primed silicon to form submonolayer surface coatings. The microgel surface density could be controlled via the deposition time and the microgel concentration in the parent suspension. In addition to their intrinsic antifouling properties, after deposition, the microgels could be loaded with a cationic antimicrobial peptide (L5) because of favorable electrostatic interactions. Loading was significantly higher in PEG-AA microgels than in pure PEG microgels. The modification of PLL-primed Si by unloaded PEG-AA microgels reduced the short-term (6 h) S. epidermidis surface colonization by a factor of 2, and the degree of inhibition increased when the average spacing between microgels was reduced. Postdeposition L5 peptide loading into microgels further reduced bacterial colonization to the extent that, after 10 h of S. epidermidis culture in tryptic soy broth, the colonization of L5-loaded PEG-AA microgel-modified Si was comparable to the very small level of colonization observed on macroscopic PEG gel controls. The fact that these microgels can be deposited by a nonline-of-sight self-assembly process and hinder bacterial colonization opens the possibility of modifying the surfaces of topographically complex biomedical devices and reduces the rate of biomaterial-associated infection.

The Effect of Zirconia in Hydroxyapatite on Staphylococcus epidermidis Growth.

Synthetic hydroxyapatite (HA) has been widely used and developed as the material for bone substitute in medical applications. The addition of zirconia is needed to improve the strength of hydroxyapatite as the bone substitute. One of the drawbacks in the use of biomedical materials is the occurrence of biomaterial-centred infections. The recent method of limiting the presence of microorganism on biomaterials is by providing biomaterial-bound metal-containing compositions. In this case, S. epidermidis is the most common infectious organism in biomedical-centred infection. Objective. This study was designed to evaluate the effect of zirconia concentrations in hydroxyapatite on the growth of S. epidermidis. Methods and Materials. The subjects of this study were twenty hydroxyapatite discs, divided into four groups in which one was the control and the other three were the treatment groups. Zirconia powder with the concentrations of 20%, 30%, and 40% was added into the three different treatment groups. Scanning electron microscope analysis was performed according to the hydroxyapatite and hydroxyapatite-zirconia specimens. All discs were immersed into S. epidermidis culture for 24 hours and later on they were soaked into a medium of PBS. The cultured medium was spread on mannitol salt agar. After incubation for 24 hours at 37°C , the number of colonies was measured with colony counter. Data obtained were analyzed using the ANOVA followed by the pairwise comparison. Result. The statistical analysis showed that different concentrations of zirconia powder significantly influenced the number of S. epidermidis colony (P < 0.05) . Conclusion. The addition of zirconia into hydroxyapatite affected the growth of S. epidermidis. Hydroxyapatite with 20% zirconia proved to be an effective concentration to inhibit the growth of S. epidermidis colony.

The diagnostic importance of eosinophil granulocytes in the CSF of children with ventricular-peritoneal shunt systems.

We investigated the occurrence of cerebrospinal fluid (CSF) eosinophilia in patients with ventriculo-abdominal shunt systems with regard to possible infection. For this purpose, we examined the CSF of 83 children at the time of shunt obstruction or malfunction. In 32 children (38.6%) we found more than 4% of eosinophil granulocytes in the CSF with a maximum of 76%. In 15 of these 32 children the CSF was sterile, whereas in 17 patients bacterial infection was present. In the CSF of 16 of those 17 children, Staph. epidermidis was cultivated. There was statistically significant correlation between positive Staph. epidermidis culture and the occurrence of CSF eosinophilia (P<0.05). The occurrence of CSF eosinophilia in patients with ventriculo-peritoneal shunts is well known and was mostly attributed to an allergic reaction. Our findings support the theory of an infectious etiology of the eosinophilia and are thus in line with new American and French studies. We believe that CSF eosinophilia indicates a persistent infection of the central nervous system by the contaminated shunt system. As the organism which is the most common cause we cultured Staph. epidermidis.

A Crucial Role for Exopolysaccharide Modification in Bacterial Biofilm Formation, Immune Evasion, and Virulence

Biofilms play an important role in many chronic bacterial infections. Production of an extracellular mixture of sugar polymers called exopolysaccharide is characteristic and critical for biofilm formation. However, there is limited information about the mechanisms involved in the biosynthesis and modification of exopolysaccharide components and how these processes influence bacterial pathogenesis. Staphylococcus epidermidis is an important human pathogen that frequently causes persistent infections by biofilm formation on indwelling medical devices. It produces a poly-N-acetylglucosamine molecule that emerges as an exopolysaccharide component of many bacterial pathogens. Using a novel method based on size exclusion chromatography-mass spectrometry, we demonstrate that the surface-attached protein IcaB is responsible for deacetylation of the poly-N-acetylglucosamine molecule. Most likely due to the loss of its cationic character, non-deacetylated poly-acetylglucosamine in an isogenic icaB mutant strain was devoid of the ability to attach to the bacterial cell surface. Importantly, deacetylation of the polymer was essential for key virulence mechanisms of S. epidermidis, namely biofilm formation, colonization, and resistance to neutrophil phagocytosis and human antibacterial peptides. Furthermore, persistence of the icaB mutant strain was significantly impaired in a murine model of device-related infection. This is the first study to describe a mechanism of exopolysaccharide modification that is indispensable for the development of biofilm-associated human disease. Notably, this general virulence mechanism is likely similar for other pathogenic bacteria and constitutes an excellent target for therapeutic maneuvers aimed at combating biofilm-associated infection.

Visual outcome of endophthalmitis in Sweden.

A retrospective study of 62 cases of clinically diagnosed endophthalmitis (EO) reported from 24 clinics in Sweden was carried out. Both culture negative and positive cases were included. The function of the eye was lost in 34% of all cases, while vision better than 0.1 was preserved in 41% cases. Staph. epidermidis positive and culture negative cases were associated with better visual results. The majority of eyes with cultures positive for Staph. aureus were lost or became blind. Intravitreal injection of antibiotics and vitrectomy was generally reserved for more severe cases often involving a delay in their institution. A combination of topical and systemic steroids gave better results than no steroids or only topical steroid administration.