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Dive into the research topics where Helmut Mittermayer is active.

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Featured researches published by Helmut Mittermayer.


Emerging Infectious Diseases | 2009

Methicillin-resistant Staphylococcus aureus ST398 from human patients, upper Austria.

Karina Krziwanek; Sigrid Metz-Gercek; Helmut Mittermayer

Methicillin-resistant Staphylococcus aureus (MRSA) clonal type ST398 is usually associated with animals. We examined 1,098 confirmed MRSA samples from human patients and found that 21 were MRSA ST398. Most (16) patients were farmers. Increasing prevalence from 1.3% (2006) to 2.5% (2008) shows emergence of MRSA ST398 in humans in Austria.


Wiener Klinische Wochenschrift | 2009

Methicillin-resistant Staphylococcus aureus: a new zoonotic agent?

Burkhard Springer; Ulrike Orendi; Peter Much; Gerda Höger; Werner Ruppitsch; Karina Krziwanek; Sigrid Metz-Gercek; Helmut Mittermayer

ZusammenfassungStaphylococcus aureus ist ein bedeutender Erreger von Infektionen, die in Krankenhäusern und Pflegeeinrichtungen erworben werden, und bei der Allgemeinbevölkerung. Ein Drittel der Gesamtbevölkerung ist mit Staphylococcus aureus kolonisiert, wobei das Risiko, an einer Infektion durch Staphylococcus aureus zu erkranken bei diesen kolonisierten Personen erhöht ist. Die weltweit zunehmende Antibiotikaresistenz von Staphylococcus aureus schränkt die Behandlungsmöglichkeiten von Infektionen ein und erschwert Kontrollmaßnahmen. Kurz nach Einführung des Methicillins wurde über die ersten Methicillin-resistenten Staphylococcus aureus Isolate (MRSA) berichtet. Während des letzten Jahrzehnts vollzog sich außerdem eine epidemiologische Verschiebung von den bisher dominierenden Krankenhaus assoziierten MRSA Stämmen hin zu in der Gemeinschaft erworbenen MRSA Stämmen (community acquired MRSA, CA-MRSA), welche Infektionen auch bei dem Teil der Bevölkerung hervorrufen, der keine Risikofaktoren durch Krankenhauskontakte hat. Basierend auf neueren Untersuchungen besteht für den Sequenztyp (ST) 398 eine kausale Verbindung zwischen einer MRSA Kolonisation im Viehbestand und der MRSA Besiedlung, sowie dem Auftreten von Infektionen, bei Tierzüchtern. In den Niederlanden wurde eine hohe Besiedlungsrate durch den MRSA ST398 bei Schweinen und Schweinehaltern festgestellt. Weltweite Berichte über den Nachweis von ST398 MRSA verdeutlichen, dass das Auftreten des neuen Subtyps kein spezifisch holländisches Problem darstellt. In Österreich konnte der MRSA Sequenztyp 398 in Staubproben von Schweinezuchtbetrieben und aus Lebensmitteln isoliert werden. Seit dem ersten Auftreten des Sequenztyps ST398 als Infektionserreger beim Menschen in Österreich im Jahre 2006 konnten 21 Humanisolate nachgewiesen werden, wovon allerdings nur ein geringer Teil mit Infektionen assoziiert war. MRSA müssen zukünftig auch als zoonotisches Agens betrachtet werden, wobei der Nutztierbestand ein bedeutendes Reservoir darstellt. Weitergehende Untersuchungen sind nötig, um Kontrollmaßnahmen erarbeiten und implementieren zu können.SummaryStaphylococcus aureus is a major cause of infection in hospitals and the community. One third of the general population is colonized by the bacterium, constituting a risk factor for acquisition of infection with this pathogen. Worldwide, the increasing antibiotic resistance of S. aureus complicates treatment of infection and control measures. Soon after the introduction of methicillin, the first isolates resistant to this antibiotic were reported and named methicillin-resistant S. aureus (MRSA). During the past decade a major change in MRSA epidemiology has been observed: whereas in the past MRSA was almost exclusively regarded a hospital pathogen, the advent of community-acquired MRSA has led to infections in people without hospital-related risk factors. Recent evidence has also identified a link between colonization of livestock and MRSA carriage and infections in people who work with animals. Screening of pigs and pig farmers in the Netherlands revealed high prevalence of MRSA sequence type (ST) 398 and it has become clear that the emergence of ST398 is not just a Dutch problem, as reports on livestock colonization and human infections are appearing worldwide. In Austria, the ST398 lineage has been detected in dust samples from pig breeding facilities and in food samples. Since the first Austrian detection of this emerging lineage in 2006, 21 human isolates, partially associated with infections, have been observed. MRSA has to be regarded as a new emerging zoonotic agent and livestock may constitute a growing reservoir of the ST398 lineage. More information is needed so that control measures to reduce the impact of the emerging MRSA ST398 lineage on public health can be developed and implemented.


BMC Infectious Diseases | 2009

Ten years of antibiotic consumption in ambulatory care: Trends in prescribing practice and antibiotic resistance in Austria

Sigrid Metz-Gercek; A Maieron; Reinhild Strauß; Peter Wieninger; Petra Apfalter; Helmut Mittermayer

BackgroundThe primary aims of this study were (i) to determine the quantity and pattern of antibiotic use in Austria between 1998 and 2007 and (ii) to analyze antibiotic resistance rates in relation to antibiotic consumption in important clinical situations in order to provide data for empirical therapeutic regimens for key indications.MethodsConsumption data and resistance data were obtained via the Austrian surveillance networks European Antimicrobial Resistance Surveillance System (EARSS) and European Surveillance on Antimicrobial Consumption (ESAC). The EARSS collects data on isolates from blood and cerebrospinal fluid obtained predominantly in the hospital setting. The Anatomical Therapeutic Chemical (ATC) classification and the Defined Daily Dose (DDD) measurement units were assigned to the data. The number of DDDs and packages per 1,000 inhabitants (PID) were used to calculate the level of antibiotic consumption. Antibiotic resistance was expressed in resistance rates, i.e., the percentage of resistant isolates compared to all isolates of one bacterial species.ResultsThe overall antibiotic consumption measured in DIDs increased by 10% between 1998 and 2007, whereas PIDs decreased by 3%. The consumption of substances within the drug utilization 90% segment (measured in PID) increased for ciprofloxacin (+118.9), clindamycin (+76.3), amoxicillin/clavulanic acid (+61.9%), cefpodoxime (+31.6), azithromycin (+24.7); and decreased for erythromycin (-79.5%), trimethoprim (-56,1%), norfloxacin (-48.8%), doxycycline (-44.6), cefaclor (-35.1%), penicillin (-34.0%), amoxicillin (-22.5), minocycline (-21.9%) and clarithromycin (-9.9%). Starting in 2001, an increase in the percentage of invasive E. coli isolates resistant to aminopenicillins (from 35% to 53%), fluoroquinolones (from 7% to 25.5%) and third-generation cephalosporins (from 0% to 8.8%) was observed. The percentage of nonsusceptible or intermediate penicillin-resistant pneumococcal isolates remained stable over this time period at around 5%. For macrolides, the rate of resistant isolates increased from 5% to 12.8%, with a peak in 2005 at 14.7%.ConclusionThe Austrian resistance data can not explain the fundamental change in prescribing practice. The more frequent use of ciprofloxacin has most likely contributed to rising resistance rates in E. coli in Austria. Penicillin G is still a highly effective substance for the treatment of invasive infections caused by pneumococci.


Clinical Microbiology and Infection | 2011

Trends in the occurrence of MRSA strains in Upper Austria from 2006 to 2009

Karina Krziwanek; S. Metz-Gercek; Helmut Mittermayer

Between 2006 and 2009, all MRSA isolates recovered from human patients in Upper Austria were subjected to molecular biological analysis. Whereas the isolate number decreased from year to year, the proportion of the most common sequence types (ST5, ST8 and ST22) as well as the frequency of associated PFGE subtypes and spa-types remained similar. The rate of PVL-positive MRSA increased, whereupon the most common sequence types were ST152, ST8 including clone USA300, ST5, ST777 and ST88. The frequency of ST398 was high (25%) in relation to the PVL-positive clones. Thus, we consider a special focus on community-associated MRSA to be necessary.


PLOS ONE | 2015

Genetic Variation of Bordetella pertussis in Austria.

Birgit Wagner; Helen Melzer; Georg Freymüller; Sabine Stumvoll; Pamela Rendi-Wagner; Maria Paulke-Korinek; Andreas Repa; Frits R. Mooi; Herwig Kollaritsch; Helmut Mittermayer; Harald H. Kessler; Gerold Stanek; Ralf Steinborn; Michael Duchêne; Ursula Wiedermann

In Austria, vaccination coverage against Bordetella pertussis infections during infancy is estimated at around 90%. Within the last years, however, the number of pertussis cases has increased steadily, not only in children but also in adolescents and adults, indicating both insufficient herd immunity and vaccine coverage. Waning immunity in the host and/or adaptation of the bacterium to the immunised hosts could contribute to the observed re-emergence of pertussis. In this study we therefore addressed the genetic variability in B. pertussis strains from several Austrian cities. Between the years 2002 and 2008, 110 samples were collected from Vienna (n = 32), Linz (n = 63) and Graz (n = 15) by nasopharyngeal swabs. DNA was extracted from the swabs, and bacterial sequence polymorphisms were examined by MLVA (multiple-locus variable number of tandem repeat analysis) (n = 77), by PCR amplification and conventional Sanger sequencing of the polymorphic regions of the prn (pertactin) gene (n = 110), and by amplification refractory mutation system quantitative PCR (ARMS-qPCR) (n = 110) to directly address polymorphisms in the genes encoding two pertussis toxin subunits (ptxA and ptxB), a fimbrial adhesin (fimD), tracheal colonisation factor (tcfA), and the virulence sensor protein (bvgS). Finally, the ptxP promoter region was screened by ARMS-qPCR for the presence of the ptxP3 allele, which has been associated with elevated production of pertussis toxin. The MLVA analysis revealed the highest level of polymorphisms with an absence of MLVA Type 29, which is found outside Austria. Only Prn subtypes Prn1/7, Prn2 and Prn3 were found with a predominance of the non-vaccine type Prn2. The analysis of the ptxA, ptxB, fimD, tcfA and bvgS polymorphisms showed a genotype mixed between the vaccine strain Tohama I and a clinical isolate from 2006 (L517). The major part of the samples (93%) displayed the ptxP3 allele. The consequences for the vaccination strategy are discussed.


Wiener Klinische Wochenschrift | 2011

Citric acid inhibits growth of Helicobacter pylori in vitro: a new strategy for eradication

Zazgornik J; Helmut Mittermayer

ZusammenfassungHINTERGRUND: Infektionen mit Helicobacter pylori stellen ein weltweites gesundheitliches Problem dar. Der Zusammenhang zwischen peptischer Ulkuskrankheit und Helicobacter pylori Infektionen ist gut dokumentiert. Demgemäß ist eine Eradikation obligatorisch, jedoch sind die hohen Kosten der multimedikamentösen Therapie sowie die Resistenz von Helicobacter pylori gegen Antibiotika limitierende Faktoren. METHODEN: Die wachstumshemmende Wirkung von 3 % Wasserstoffperoxid, 8,4 % Natriumbicarbonat, 2 % Ascorbinsäure, Zitronensäure mit Natriumzitrat, 7 % und 14 % Zitronensäure Lösungen wurde in vitro an neun Helicobacter pylori Stämmen getestet. ERGEBNISSE: Von den getesteten Substanzen zeigte Zitronensäure eine stark hemmende Wirkung auf das Wachstum von Helicobacter pylori Stämmen in vitro. Der hemmende Effekt war nicht nur bei Zitronensäurelösungen sondern auch bei einer Mischung von Zitronensäure mit Natriumzitrat in niedrigerer Konzentration zu sehen. SCHLUSSFOLGERUNG: Basierend auf unseren Resultaten soll Zitronensäure für die Eradikation von Helicobacter pylori klinisch bewertet werden.SummaryBACKGROUND: About 50% of the world population is infected with Helicobacter pylori. The association of peptic ulcer disease with Helicobacter pylori is well documented. Therefore eradication is obligatory. However, the high costs of multidrug therapy, the resistance of Helicobacter pylori to antibiotics as well as the sometimes present drug intolerance are limiting factors. METHODS: The inhibitory effect of 3% hydrogen peroxide, 8.4% sodium bicarbonate, 2% ascorbic acid, citric acid in combination with sodium citrate, 7% and 14% citric acid solutions, respectively, on nine Helicobacter pylori strains were tested in vitro. RESULTS: Citric acid showed a potent inhibitory activity on growth of Helicobacter pylori strains in vitro. This was observed not only when citric acid was applied alone but also if citric acid was given together with low concentration of sodium citrate. Two percent ascorbic acid inhibited three, sodium bicarbonate two and hydrogen peroxide one of the nine tested Helicobacter pylori strains, respectively. CONCLUSIONS: Citric acid is a cheap substance present in many fruits and produced by food industry, and it demonstrated powerful inhibitory effect on the growth of Helicobacter pylori strains. On the basis of our findings citric acid should be further evaluated for the eradication of Helicobacter pylori.


Wiener Klinische Wochenschrift | 2010

Antiviral treatment of chronic hepatitis C in clinical routine

A Maieron; Sigrid Metz-Gercek; Franz Hackl; Alexander Ziachehabi; Harri Fuchsteiner; Christoph Luger; Helmut Mittermayer; Rainer Schöfl

ZusammenfassungEINLEITUNG: Mit der heute zur Verfügung stehenden Standardtherapie der chronischen Hepatitis C bestehend aus pegyliertem Interferon und Ribavirin erreichen in randomisierten und kontrollierten Studien bis 60% der Patienten eine dauerhafte Viruselimination (SVR). Die Reproduzierbarkeit der Ergebnisse in der klinischen Praxis ist unklar, deshalb untersuchten wir alle konsekutiven, therapienaiven Patienten an unserer Abteilung um die Wirksamkeit der Standardtherapie in der klinischen Routine zu überprüfen. MATERIAL UND METHODIK: Insgesamt wurden 219 Patienten mit pegyliertem Interferon Alpha (2a oder 2b) und Ribavirin (800–1200 mg/Tag) in den Jahren 2000 und 2006 behandelt. 34.8% der Genotyp 1/4/6 und 18.4 % der Genotyp 2/3 Patienten wiesen eine Fibrose Grad 3 oder 4 auf. Die Patienten wurden gemäß der gängigen Ein- und Ausschlusskriterien für klinische Studien in zwei Gruppen geteilt. Die Therapieergebnisse dieser beiden Gruppen wurden getrennt analysiert. ERGEBNISSE: 44.3 % der Patienten erreichten eine dauerhafte Viruselimination. Jene mit einer niedrigen Fibrose (F0 – F2) erreichten in 52.5 % und jene mit einer Fibrose F3 – F4 erreichten in 20.8 % einen SVR. Die SVR-Rate für Patienten mit Genotyp 1/4/6 betrug 35.4 % (SVR: F0 – F2 47.7; F3 – F4 19.6 %) und für Genotyp 2/3 67.8 %. In der Gruppe der Patienten, mit ungünstigen Voraussetzungen für die Therapie war die SVR-Rate signifikant niedriger (32.4 % vs. 50 %; p = 0.017), zudem war in dieser Gruppe die Non-Responder-Rate deutlich erhöht (30.9 % vs. 13.8 %). SCHLUSSFOLGERUNG: Bis zu einem Drittel der Patienten weisen ungünstige, zu schlechteren Therapieergebnissen führende, Voraussetzungen, für eine antivirale Therapie auf. Der Therapieerfolg ist durch Patientenselektion, Schweregrad der zu Grunde liegenden Lebererkrankung und Anteil der Patienten mit fortgeschrittener Lebererkrankung beeinflusst.SummaryOBJECTIVE: Pegylated interferon plus ribavirin is the standard treatment for chronic hepatitis C. Sustained virological response (SVR) rates of up to 60% are reported in randomized controlled trials, but it is unclear whether the results from such trials are reproducible in the clinical routine setting. We investigated consecutive treatment-naïve chronic hepatitis C patients at our center to examine the efficacy of treatment with pegylated interferon plus ribavirin in clinical routine. MATERIALS AND METHODS: Between 2000 and 2006 we treated a total of 219 patients with pegylated interferon alpha (2a or 2b) and ribavirin (800–1200 mg/d). Among them, 34.8% of patients infected with HCV genotypes 1/4/6 and 18.4% of those with genotypes 2/3 had advanced fibrosis or cirrhosis (F3–F4). For analysis of outcome we subdivided our series into two groups of patients: those who fulfilled standard inclusion criteria in randomized controlled trials and those who did not. RESULTS: The overall SVR rate was 44.3%. In patients with F0–F2 an SVR was achieved in 52.5%; in those with F3–F4 the SVR rate was 20.8%. In patients infected with genotypes 1/4/6 the SVR rate was 35.4% (SVR: F0–F2 47.7%; F3–F4 19.6%); in those with genotypes 2/3 the rate was 67.8%. The SVR rate in patients with unfavorable baseline factors was significantly lower (32.4% vs. 50%; P = 0.017) and they were more likely to be non-responders (30.9% vs. 13.8%). CONCLUSION: In everyday clinical practice, up to one-third of patients show unfavorable baseline factors for antiviral therapy, resulting in worse therapeutic outcome. Differences in therapeutic outcome are influenced by patient selection and by the proportion and severity of the underlying liver disease.


Clinical Microbiology and Infection | 2008

MRSA in Austria—an overview

Karina Krziwanek; Christoph Luger; B. Sammer; Sabine Stumvoll; Maren Stämmler; Ulrich Sagel; Wolfgang Witte; Helmut Mittermayer


Clinical Microbiology and Infection | 2008

MRSA in Austriaan overview

Karina Krziwanek; Christoph Luger; B. Sammer; Sabine Stumvoll; Maren Stämmler; Ulrich Sagel; Wolfgang Witte; Helmut Mittermayer


Wiener Klinische Wochenschrift | 2010

Hepatitis C Therapie: Ergebnisse in der klinischen Routine

A Maieron; Sigrid Metz-Gercek; Franz Hackl; Alexander Ziachehabi; Harri Fuchsteiner; Christoph Luger; Helmut Mittermayer; Rainer Schöfl

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Franz Hackl

University of Innsbruck

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Andreas Repa

Medical University of Vienna

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Birgit Wagner

Medical University of Vienna

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Georg Freymüller

University of Veterinary Medicine Vienna

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Gerold Stanek

Medical University of Vienna

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Harald H. Kessler

Medical University of Graz

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Helen Melzer

Medical University of Vienna

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