Genetic Variation of Bordetella pertussis in Austria.

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.

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

BACKGROUND: 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.

Antiviral treatment of chronic hepatitis C in clinical routine.

OBJECTIVE: 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.

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

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.

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

BACKGROUND: The 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 esistance rates in relation to antibiotic consumption in important clinical situations in order to provide data for empirical therapeutic regimens for key indications. METHODS: Consumption 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. RESULTS: The 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%. CONCLUSION: The 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.

Methicillin-resistant Staphylococcus aureus: a new zoonotic agent?

Staphylococcus 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.

The European surveillance activities EARSS and ESAC in the context of ABS International.

Development of resistance obstructs the successful use of antimicrobial drugs, since shortly after each and every introduction of a new antibiotic resistant pathogens have emerged. The hope of being able to reverse or at least slow down the occurrence of antibiotic resistance has led to a number of actions and initiatives. The project "ABS International - Implementing antibiotic strategies for appropriate use of antibiotics in hospitals in member states of the European Union", together with the European Antimicrobial Resistance Surveillance System (EARSS) and the European Surveillance on Antimicrobial Consumption (ESAC), covers a large proportion of possible actions against antibiotic resistance. The data generated by EARSS and ESAC are an essential prerequisite for targeted interventions to cope with the problem of antibiotic resistance. The project ABS International constitutes an impressive initiative to optimize the situation in hospitals in nine European member states.