A methicillin rezisztens és érzékeny Staphylococcus aureus törzsek virulenciájának genetikai, valamint az általuk okozott fertőzések molekuláris pathomechanizmusának in vitro és in vivo vizsgálata = Genetics of the virulence of methicillin resistant versus sensitive Staphylococcus aureus strains, as well as in vitro and in vivo studies on the molecular pathomechanisms of associated infections

Vizsgáltuk az MRSA törzsek gyakoriságát a Semmelweis, a Skopjei és a Debreceni Egyetem klinikáin 2001-2005 között kezelt betegekből kitenyészett S. aureus törzsek között. A magyar törzsek 7.8%-a, ill. 7.2%-a, míg a macadón törzsek 31.4%-a volt MRSA. Az MRSA törzsek multirezisztensek. A rezisztencia szint >256 mg/L. PFGE vizsgálattal az MRSA törzsek között dominált az A genotípus. PCR-rel az MRSA törzsek több mint fele, míg az MSSA törzseknek csak az 1/3-a tartalmazott négy adhéziós gént különböző kombinációban. 2 és 3 génkombinációt az MSSA törzsek tartalmaztak nagyobb arányban. A cytotoxin gének közül a a gamma és gamma variáns haemolysin gént szignifikánsan nagyobb arányban tartalmazták az MRSA törzsek mint az MSSA-k. Szignifikánsan gyakoribb volt az 4 és 5 cytitoxin gén kombináció az MRSA mint az MSSA törzsekben. Szignifikánsan gyakoribbak voltak enterotoxin-A, -D és az enterotoxin-like toxin gének az MRSA-kban mint az MSSA-kban, kivéve a H, L és U gént, melyre az ellenkező igaz. Orvostanhallgatókból kitenyészett 137 MSSA törzsben kisebb arányban találtunk enterotoxin géneket. Az accesory gene regulator I. típust azonos arányban találtuk az MRSA és MSSA törzsekben, mig a II. típus az MRSA-ban, a III. és IV. típus az MSSA-ban volt gyakoribb. Számos új vancomycin, teicoplanin, eremomycin és ristocetin származékot vizsgáltunk MRSA és vancomycin-rezisztens entercoccusok ellen, s közülük néhány hatásásnak bizonyult feltételezhetően terápiás koncentracióban. | The incidence of MRSA strains isolated from inpatients treated at the clinics of the Semmelweis and Skopje and Debrecen Universities, respectively, between 2001-2005 was studied. 7.8% and 7.2% of the Hungarian and 31.4% of the Macedonian strains were MRSA. They proved to be multiple resistant to antibiotics. The quantitative level of resistance was >256 mg/L. PFGE showed a dominance of genotype A. PCR revealed more than half of the MRSA strains, while only 1/3 of the MSSA ones to possess four adhesin genes in various combinations. MSSA strains contained 2-or 3-gene combinations in higher rates. Of cytotoxin genes, haemolysin gamma and gamma variant genes were significantly more frequent in MRSA than in MSSA strains The combinations of 4 and 5 cytotoxin genes were significantly more frequent in MRSA than in MSSA strains. MRSA strains harboured enterotoxin-A, -D and enterotoxin-like toxin genes at significantly higher rates than MSSA ones except for gene H, L and U showing the opposite. 137 MSSA strains isolated from medical students had enterotoxin genes at considerably lower rates. Accessory gene regulator type I was at the same rate in MRSA and MSSA strains, while type II in MRSA, type III and IV in MSSA were more frequent. A number of derivetives of vancomycin, teiciplanin, eremomycin and ristocetin was studied on MRSA and vancomycin-resistant enterococci and some of them proved to be efficient at supposably therapeutic concentrations

Formulation of Chlorine-Dioxide-Releasing Nanofibers for Disinfection in Humid and CO2-Rich Environment

Background: Preventing infectious diseases has become particularly relevant in the past few years. Therefore, antiseptics that are harmless and insusceptible to microbial resistance mechanisms are desired in medicine and public health. In our recent work, a poly(ethylene oxide)-based nanofibrous mat loaded with sodium chlorite was formulated. Methods: We tested the chlorine dioxide production and bacterial inactivation of the fibers in a medium, modeling the parameters of human exhaled air (ca. 5% (v/v) CO(2), T = 37 °C, RH > 95%). The morphology and microstructure of the fibers were investigated via scanning electron microscopy and infrared spectroscopy. Results: Smooth-surfaced, nanoscale fibers were produced. The ClO(2)-producing ability of the fibers decreased from 65.8 ppm/mg to 4.8 ppm/mg with the increase of the sample weight from 1 to 30 mg. The effect of CO(2) concentration and exposure time was also evaluated. The antibacterial activity of the fibers was tested in a 24 h experiment. The sodium-chlorite-loaded fibers showed substantial antibacterial activity. Conclusions: Chlorine dioxide was liberated into the gas phase in the presence of CO(2) and water vapor, eliminating the bacteria. Sodium-chlorite-loaded nanofibers can be sources of prolonged chlorine dioxide production and subsequent pathogen inactivation in a CO(2)-rich and humid environment. Based on the results, further evaluation of the possible application of the formulation in face-mask filters as medical devices is encouraged

Prevalence of Staphylococcus aureus in wild hedgehogs (Erinaceus europaeus) and first report of mecC-MRSA in Hungary

In 2011 mecC, a new mecA gene homologue, was described in a bovine isolate in the UK. Since then, mecC-positive methicillin-resistant Staphylococcus aureus (mecC-MRSA) has also been found in wild animals. An especially high prevalence of mecC-MRSA has been reported among hedgehogs in Sweden (64%) and Denmark (61%). Based on these findings we aimed to survey the hedgehog population for mecC-MRSA in Hungary. Altogether 200 hedgehogs were screened for Staphylococcus aureus using a culture-based method. The antibiotic susceptibility of the isolates to nine drugs was determined, their genetic relatedness was established by PFGE and spa-typing, and virulence genes were identified by PCR. Whole genome sequencing was performed for the single mecC-MRSA isolate found. Of the 200 animals, 13 were carriers of S. aureus (6.5%). Among these, one isolate was mecA positive and one was mecC positive. The isolates were susceptible to non-beta-lactam antibiotics. Toxin genes were not found, but the majority carried genes responsible for adhesion and biofilm production. The mecC-MRSA isolate was a single-locus variant of ST130, had a new spa type (t19701) and belonged to SCCmec type XI. It carried a recently described, novel exfoliative toxin (etE). This is the first report of mecC-MRSA in Hungary and the first survey of staphylococcus carriage among wild animals in the country. The mecC prevalence was much lower than in Northern European countries and rather similar to other countries in our region. MecC-MRSA could potentially emerge as a novel human pathogen, especially where close contact occurs between humans and animals

The effect of indomethacin, myeloperoxidase, and certain steroid hormones on bactericidal activity: an ex vivo and in vivo experimental study.

BACKGROUND: The role of myeloperoxidase (MPO) is essential in the killing of phagocytosed bacteria. Certain steroid hormones increase MPO plasma concentration. Our aim was to test the effect of MPO, its inhibitor indomethacin, and certain steroid hormones on bactericidal activity. METHODS: Human polymorphonuclear leukocytes (PMN) were incubated with opsonised Escherichia coli and either MPO, indomethacin, estradiol, or hydrocortisone. Intracellular killing capacity was evaluated with UV microscopy after treatment with fluorescent dye. Next, an in vivo experiment was performed with nine groups of rats: in the first phase of the study indomethacin treatment and Pasteurella multocida infection (Ii), indomethacin treatment without infection (I0), untreated control with infection (Mi) and untreated control without infection (M0); in the second phase of the study rats with infection and testosterone treatment (NT), castration, infection and testosterone treatment (CT), castration, infection and estradiol treatment (CE), non-castrated infected control (N0), and castrated infected control (C0). After treatment bacteria were reisolated from the liver and heart blood on agar plates, and laboratory parameters were analyzed. For the comparison of laboratory results ANOVA or Kruskal-Wallis test and LSD post hoc test was used. RESULTS: Indomethacin did not have a remarkable effect on the bacterial killing of PMNs, while the other compounds increased bacterial killing to various degrees. In the animal model indomethacin and infection caused a poor clinical state, a great number of reisolated bacteria, elevated white blood cell (WBC) count, decreased C-reactive protein (CRP) and serum albumin levels. Testosterone treatment resulted in less bacterial colony numbers in group NT, but not in group CT compared to respective controls (N0, C0). Estradiol treatment (CE) decreased colony numbers compared to control (C0). Hormone administration resulted in lower WBC counts, and in group CE, a decreased CRP. CONCLUSIONS: MPO, estradiol, and hydrocortisone improve bacterial killing activity of PMNs. Indomethacin treatment and castration weaken immune responses and clinical state of infected rats, while testosterone and estradiol have a beneficial effect

Resitance to β-lactams and glycopeptides in staphylococci and sterptococci (A review)

Molecular mechanisms of the action of β-lactam and glycopeptide antibiotics, as well as genetic background and phenotipical features of the resistance of staphylococci, streptococci and enterococci to these antibiotics are reviewed. Furthermore, susceptibility patterns concerning β-lactam and glycopeptide drugs of staphylococcal, streptococcal, as well as enterococcal strains isolated from clinical specimens at the Semmelweis University of Medicine, Budapest, Hungary between January 1997 and December 2000 are also presented

Antiretroviral effect of 4-thio-uridylate against human immunodeficiency virus type 1

Antiretroviral effect of thiolated nucleotide 4-thio-uridylate (S4UMP, designated as UD29) against human immunodeficiency virus type 1 (HIV-1) have been quantitatively determined in cell-based viral infectivity assays. In syntitium inhibition assay on MT-2 human T-cell line UD29 prevented cell fusion and formation of syntitia induced by HIV-1IIIB with IC50 values of 11.7 μg/ml. In a single-cycle viral infection assay (MAGI assay) UD29 proved to have a potent inhibitory effect against HIV-1IIIB on HeLaCD4-LTR/β-gal cells, which was dose dependent with IC50 values of 4.75 μg/ml and IC90 of 39.7 μg/ml. UD29 showed a most prominent antiviral effect when administered 30 min prior HIV-1 infection. As HIV entry requires thiol/disulfide exchange process, results suggest that reactive -SH group of enol-form of the thiolated nucleotide may interfere with the function of cell surface proteins. UD29 cannot penetrate into cells and may have an interactive role in redox processes active in viral entry

Effect of dentin powder on the antimicrobial properties of hyperpure chlorine-dioxide and its comparision to conventional endodontic disinfecting agents

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Comparing the efficacy of hyper-pure chlorine-dioxide with other oral antiseptics on oral pathogen microorganisms and biofilm in vitro.

This study examines the antibacterial properties of sodium hypochlorite (NaOCl), chlorhexidine gluconate (CHX), Listerine(R), and high purity chlorine dioxide (Solumium, ClO2) on selected common oral pathogen microorganisms and on dental biofilm in vitro. Antimicrobial activity of oral antiseptics was compared to the gold standard phenol. We investigated Streptococcus mutans, Lactobacillus acidophilus, Enterococcus faecalis, Veillonella alcalescens, Eikenella corrodens, Actinobacillus actinomycetemcomitans and Candida albicans as some important representatives of the oral pathogens. Furthermore, we collected dental plaque from the upper first molars of healthy young students. Massive biofilm was formed in vitro and its reduction was measured after treating it with mouthrinses: CHX, Listerine(R) or hyper pure ClO2. Their biofilm disrupting effect was measured after dissolving the crystal violet stain from biofilm by photometer. The results have showed that hyper pure ClO2 solution is more effective than other currently used disinfectants in case of aerobic bacteria and Candida yeast. In case of anaerobes its efficiency is similar to CHX solution. The biofilm dissolving effect of hyper pure ClO2 is significantly stronger compared to CHX and Listerine(R) after 5 min treatment. In conclusion, hyper pure ClO2 has a potent disinfectant efficacy on oral pathogenic microorganisms and a powerful biofilm dissolving effect compared to the current antiseptics, therefore high purity ClO2 may be a new promising preventive and therapeutic adjuvant in home oral care and in dental or oral surgery practice