Effects of Ulva sp. Extracts on the Growth, Biofilm Production, and Virulence of Skin Bacteria Microbiota: Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes Strains.

Ulva sp. is known to be a source of bioactive compounds such as ulvans, but to date, their biological activity on skin commensal and/or opportunistic pathogen bacteria has not been reported. In this study, the effects of poly- and oligosaccharide fractions produced by enzyme-assisted extraction and depolymerization were investigated, for the first time in vitro, on cutaneous bacteria: Staphylococcus aureus, Staphylococcus epidermidis, and Cutibacterium acnes. At 1000 µg/mL, poly- and oligosaccharide fractions did not affect the growth of the bacteria regarding their generation time. Polysaccharide Ulva sp. fractions at 1000 µg/mL did not alter the bacterial biofilm formation, while oligosaccharide fractions modified S. epidermidis and C. acnes biofilm structures. None of the fractions at 1000 µg/mL significantly modified the cytotoxic potential of S. epidermidis and S. aureus towards keratinocytes. However, poly- and oligosaccharide fractions at 1000 µg/mL induced a decrease in the inflammatory potential of both acneic and non-acneic C. acnes strains on keratinocytes of up to 39.8%; the strongest and most significant effect occurred when the bacteria were grown in the presence of polysaccharide fractions. Our research shows that poly- and oligosaccharide Ulva sp. fractions present notable biological activities on cutaneous bacteria, especially towards C. acnes acneic and non-acneic strains, which supports their potential use for dermo-cosmetic applications.

Intracavitary and Systemic Daptomycin for Successful Treatment of a Postpneumonectomy Intrathoracic Infection.

Treatment of an infected postpneumonectomy cavity is very difficult. We present a patient with an infection of a postpneumonectomy cavity by Staphylococcus epidermidis treated with local daptomycin for different dwell times, maintaining high antibiotic levels above the MIC. Clinical and microbiological cure were achieved successfully.

Antibiofilm Activity of Electrical Current in a Catheter Model.

Catheter-associated infections are difficult to treat with available antimicrobial agents because of their biofilm etiology. We examined the effect of low-amperage direct electrical current (DC) exposure on established bacterial and fungal biofilms in a novel experimental in vitro catheter model. Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida parapsilosis biofilms were grown on the inside surfaces of polyvinyl chloride (PVC) catheters, after which 0, 100, 200, or 500 µA of DC was delivered via intraluminally placed platinum electrodes. Catheter biofilms and intraluminal fluid were quantitatively cultured after 24 h and 4 days of DC exposure. Time- and dose-dependent biofilm killing was observed with all amperages and durations of DC administration. Twenty-four hours of 500 µA of DC sterilized the intraluminal fluid for all bacterial species studied; no viable bacteria were detected after treatment of S. epidermidis and S. aureus biofilms with 500 µA of DC for 4 days.

Characterization of coagulase-negative staphylococcus species from cows' milk and environment based on bap, icaA, and mecA genes and phenotypic susceptibility to antimicrobials and teat dips.

The aim of this study was to investigate whether the main coagulase-negative staphylococci (CNS) species involved in bovine intramammary infections (IMI) possess specific characteristics that promote colonization of the udder. Virulence markers associated with biofilm formation, antimicrobial resistance, and biocide tolerance were compared between typically contagious CNS species (Staphylococcus chromogenes, Staphylococcus epidermidis, Staphylococcus haemolyticus, and Staphylococcus simulans) and those rarely causing IMI (Staphylococcus sciuri, Staphylococcus equorum, and others) to find possible associations with pathogenicity. Coagulase-negative staphylococci isolates (n=366) belonging to 22 different species were analyzed by PCR for the presence of the biofilm-associated genes bap and icaA, and the methicillin resistance gene mecA. A selection of 82 isolates was additionally tested for their susceptibility to 5 antibiotics and 2 commercial teat dip products. Minimum inhibitory concentrations of antimicrobials were determined by Etest (AB bioMérieux, Marcy l'Etoile, France), and a microdilution method was optimized to determine minimum biocidal concentrations of teat dips. The bap, icaA, and mecA genes were detected significantly more in isolates from CNS species typically living in the cows' environment than in isolates from IMI-causing species. Antimicrobial resistance was mainly against erythromycin (23%) or oxacillin (16%), and was detected more often in the environmental species. The isolates least susceptible to the teat dips belonged to the IMI-causing species Staph. chromogenes and Staph. simulans. We concluded that carriage of biofilm genes and antimicrobial resistance were not associated with the ability to colonize the mammary gland because free-living CNS species constituted a more significant reservoir of biofilm and resistance determinants than did IMI-causing species. In contrast, increased tolerance to biocides may favor the establishment of bovine IMI by some CNS species.

Prophylactic effect of intravenous moxifloxacin in a rabbit model of Staphylococcus epidermidis endophthalmitis.

PURPOSE: To compare the prophylactic effects of intravenous moxifloxacin and vancomycin for Staphylococcus epidermidis endophthalmitis in a rabbit model. METHODS: Albino rabbits (n = 60) were divided into three groups. Intravenous moxifloxacin was injected into 20 animals (group 1), and intravenous vancomycin was injected into 20 animals (group 2). In group 3, 20 animals received 0.9% normal saline. After these prophylactic intravenous injections, the right eyes of the 60 rabbits were injected intravitreally with 10(5) colony-forming units of S. epidermidis. Intravenous antibiotic injection was repeated on days 1, 2, and 3 after infection. Clinical features were evaluated on days 1, 3, 5, and 7 after infection, and 10 eyes per group were then enucleated for histopathologic examination. Vitreous aspirates were obtained for bacterial culture on days 1, 3, 5, and 7 after infection from the other 10 eyes per group. RESULTS: The moxifloxacin group showed significant clinical effects at days 1, 3, 5, and 7 (P = 0.019, < 0.001, < 0.001, and < 0.001, respectively); bacteriologic results at days 1, 3, 5, and 7 (P = 0.001, 0.002, 0.01, and 0.002, respectively); and histopathologic results, with less severe inflammation and relatively well-preserved retinal architecture. However, no difference was detected between the vancomycin group and control group in any aspect examined. CONCLUSIONS: Intravenously administered moxifloxacin showed a significant prophylactic effect against S. epidermidis endophthalmitis. Thus, intravenous moxifloxacin may be a useful prophylactic medication against postoperative endophthalmitis.

Daptomycin is effective for treatment of experimental endocarditis due to methicillin-resistant and glycopeptide-intermediate Staphylococcus epidermidis.

This study evaluated the daptomycin activity against two methicillin-resistant Staphylococcus epidermidis (MRSE) clinical isolates with different vancomycin susceptibilities: MRSE-375, with a vancomycin MIC of 2 microg/ml, and NRS6, a glycopeptide-intermediate S. epidermidis (GISE) strain with a vancomycin MIC of 8 microg/ml. The in vivo activity of daptomycin at two different doses (standard dose [SD-daptomycin], 6 mg/kg of body weight/day intravenously [i.v.]; high dose [HD-daptomycin], 10 mg/kg/day i.v.) was evaluated in a rabbit model of infective endocarditis and compared with that of a standard dose of vancomycin (SD-vancomycin; 1 g i.v. every 12 h) for 2 days. For the MRSE-375 strain, high-dose vancomycin (HD-vancomycin; 1 g i.v. every 6 h) was also studied. For MRSE-375, SD- and HD-daptomycin therapy sterilized significantly more vegetations than SD-vancomycin therapy (9/15 [60%] and 11/15 [73%] vegetations, respectively, versus 3/16 [19%] vegetations; P = 0.02 and P = 0.002, respectively). HD-daptomycin sterilized more vegetations than HD-vancomycin (11/15 [73%] versus 5/15 [33%] vegetations; P = 0.03) and was more effective than SD- and HD-vancomycin in reducing the density of bacteria in valve vegetations (0 log(10) CFU/g vegetation [interquartile range {IQR}, 0 to 1 log(10) CFU/g vegetation] versus 2 log(10) CFU/g vegetation [IQR, 2 to 2 log(10) CFU/g vegetation] and 2 log(10) CFU/g vegetation [IQR, 0 to 2.8 log(10) CFU/g vegetation]; P = 0.002 and P = 0.01, respectively). For the NRS6 strain, SD- and HD-daptomycin were significantly more effective than vancomycin in reducing the density of bacteria in valve vegetations (3.7 log(10) CFU/g vegetation [IQR, 2 to 6 log(10) CFU/g vegetation] versus 7.1 log(10) CFU/g vegetation [IQR, 5.2 to 8.5 log(10) CFU/g vegetation]; P = 0.02). In all treatment arms, isolates recovered from vegetations remained susceptible to daptomycin and vancomycin and had the same MICs. In conclusion, daptomycin at doses of 6 mg/kg/day or 10 mg/kg/day is more effective than vancomycin for the treatment of experimental endocarditis due to MRSE and GISE.

Herida craneal por arma de fuego / Cranial gunshot wound

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Phenotypic and genotypic markers of Staphylococcus epidermidis virulence.

OBJECTIVES: To analyze Staphylococcus epidermidis strains, previously tested for their virulence in a mouse model of subcutaneous infection, for various phenotypic traits (biofilm density, extracellular polysaccharide, slime-associated antigen (SAA)) and for the presence of the ica gene cluster, to determine which of these phenotypic and genotypic methods best correlates with virulence in the mouse model. METHODS: The quantitative biofilm assay was performed on 10 strains of S. epidermidis, comprising (1) RP62A (ATCC 35984), (2) the strongest and weakest biofilm producers in our collection, (3) a pair of phenotypic variants, and (4) a strain whose biofilm density was enhanced in iron-limited media. Biofilm density was measured after growth at 37 degrees C and at ambient temperature, in trypticase soy broth (TSB) with and without glucose supplementation and using both chemical and heat fixation. Strains were assayed for SAA using a double immunodiffusion method. Extracellular polysaccharide was detected by transmission electron microscopy (TEM). A 546-base-pair segment of the ica gene cluster was amplified by PCR. RESULTS: Biofilm formation in TSB, glucose-enriched TSB, extracellular polysaccharide (observed by TEM), expression of SAA and presence of the ica gene predicted virulence of nine, nine, nine, eight and eight of 10 strains, respectively. The phenotypic expression of biofilm and related properties was medium and temperature dependent. We encountered one ica-positive strain that failed to express biofilm in standard TSB at 37 degrees C, but was virulent in a mouse model, and another strain that lacked ica, produced biofilm and was virulent in the model. CONCLUSIONS: Mouse virulence in our model can be predicted by any of the phenotypic or genotypic methods examined for > or = 80% of strains. Medium and incubation conditions affect the expression of phenotypic markers by some strains. For the remaining strains, possible reasons for inconsistencies between the presence of the ica gene, phenotypic markers and mouse virulence include (1) dependence of biofilm on genes other than ica, (2) sequence differences in ica, (3) dependence of biofilm expression in vivo on strain characteristics and media used to prepare inocula for in vivo studies.

Prophylaxis of implant-related staphylococcal infections using tobramycin-containing bone cement.

In a rabbit model, premixed tobramycin-containing bone cement was studied for its efficacy to prevent infections with two frequently encountered staphylococcal species in arthroplasty surgery. After intramedullary inoculation with staphylococci, either standard or premixed tobramycin-containing Simplex-P bone cement was injected in the right femur of 120 rabbits. Development of infection was examined by culture of femoral bone after 7 or 28 days. Loss of body weight and elevated erythrocyte sedimentation rate in the control rabbits inoculated with Staphylococcus aureus were seen in the first postoperative week, returning to normal in 28 days. Inoculation with Staphylococcus epidermidis resulted only in a low-grade infection. All rabbits receiving premixed tobramycin-containing bone cement were free of signs of infection, and all their cultures were negative. Culture yield from Staphylococcus aureus controls increased with time and inoculum dose. Staphylococcus epidermidis controls needed higher inoculum doses to establish an infection, while culture yield decreased in time. These differences in mode of prosthesis-related infection are explained by differences in virulence factors.

Heterogeneously vancomycin-resistant Staphylococcus epidermidis strain causing recurrent peritonitis in a dialysis patient during vancomycin therapy.

Methicillin-resistant Staphylococcus epidermidis (MRSE) was recovered over a 2-month period from the dialysis fluid of a peritoneal dialysis (PD) patient who experienced recurrent episodes of peritonitis during therapeutic and prophylactic use of vancomycin. Characterization of five consecutive MRSE isolates by molecular and microbiological methods showed that they were representatives of a single strain, had reduced susceptibility to vancomycin, did not react with DNA probes specific for the enterococcal vanA or vanB gene, and showed characteristics reminiscent of the properties of a recently described vancomycin-resistant laboratory mutant of Staphylococcus aureus. Cultures of these MRSE isolates were heterogeneous: they contained-with a frequency of 10(-4) to 10(-5)-bacteria for which vancomycin MICs were high (25 to 50 microg/ml) which could easily be selected to "take over" the cultures by using vancomycin selection in the laboratory. In contrast, the five consecutive MRSE isolates recovered from the PD patient during virtually continuous vancomycin therapy showed no indication for a similar enrichment of more resistant subpopulations, suggesting the existence of an "occult" infection site in the patient (presumably at the catheter exit site) which was not accessible to the antibiotic.

[The effect of therapeutic mud on the viability and persistence properties of bacteria]. / Vliianie lechebnoi griazi na zhiznesposobnost' i persistentnye svoistva bakterii.

The influence of therapeutic salt mud on the viability and some biological properties of bacteria, responsible for their survival in the macroorganisms, was shown. Therapeutic mud had low bactericidal properties, and enterobacteria were, on the whole, even less sensitive to these properties than staphylococci. Therapeutic mud inhibited the capacity of bacteria for inactivating complement, lysozyme and the bactericidal component of the preparation of interferon and also reduced the hydrophobic properties of bacterial cells. At the same time Escherichia were found to be more susceptible to the modifying action of the mud than staphylococci. The greatest effect on the hydrophobic properties and anticomplement activity of bacteria was observed after their incubation in mud solution.

[The dynamics of the species composition and antilysozymal activity of ejaculate microflora under the action of local hyperthermia]. / Dinamika vidovogo sostava i antilizotsimnoi aktivnosti mikroflory éiakuliata pod vozdeistviem lokal'noi gipertermii.

Changes in the antilysozyme activity of bacteria under the action of high temperature and short-wave hyperthermia have been studied. The regulating influence of these factors on the species composition and persistence characteristics of the microflora of ejaculate obtained from sterile patients has been demonstrated. A method for the treatment of male sterility is proposed.

Iron chelator, exopolysaccharide and protease production in Staphylococcus epidermidis: a comparative study of the effects of specific growth rate in biofilm and planktonic culture.

The growth rate of Staphylococcus epidermidis was controlled for populations growing as a biofilm and perfused with supplemented, simple-salts medium. Production of iron chelators, extracellular protease and exopolysaccharide (EPS) by these populations was assessed as a function of specific growth rate and compared to that by planktonic populations grown in the same medium within a chemostat. Perfused biofilms increased their iron chelator and protease production with increasing growth rate. Chemostat populations decreased their production of iron chelators with increasing growth rate, whilst showing much enhanced production of proteases at intermediate growth rates (mu 0.15-0.25 h-1). Production of iron chelator and protease was generally 2-50 times higher by biofilms than by planktonic populations. EPS production was low and relatively unaffected by growth rate for the chemostat cultures (about 0.2 micrograms per unit cell mass) but high for the attached biofilms, particularly at slow growth rates (about 4 micrograms per unit cell mass). EPS production within the biofilms decreased markedly with increasing growth rate. At growth rates of 0.35 h-1 and above, the levels of EPS for biofilms and planktonic populations were equivalent. The results of this study clearly indicate that growth as a biofilm markedly influences extracellular virulence factor production by S. epidermidis.