Dalbavancin reduces biofilms of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE).

Activity of dalbavancin against methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) in biofilm was investigated and the microbicidal biofilm concentrations (MBC) were determined. Biofilms obtained from ten MRSA and ten MRSE bloodstream isolates, collected from patients in the General Hospital of Vienna between 2012 and 2015, were incubated with dalbavancin in trypticase soy broth (TSB) in serial dilution from 0.0625 mg/l to 256 mg/l using a microtiter plate biofilm model. The plates were incubated for 24 h at 37 ° C and 50% humidity. Biofilms were fixed with 2.5% glutaraldehyde and stained with crystal violet. Subsequently the optical density (OD620) was used to measure the MBC, defined as the concentration of dalbavancin leading to a 50% reduction of biofilm. MBC for MRSA was 1 mg/l-4 mg/l (minimal inhibitory concentrations (MIC) 0.0312 mg/l-0.064 mg/l). MBC for MRSE was 2 mg/l-16 mg/l (MIC 0.023 mg/l-0.0625 mg/l). Dalbavancin successfully reduced MRSA and MRSE in biofilms, and therefore provides a promising option for the treatment of biofilm-associated infections.

Exposure to Echinococcus multilocularis, Toxocara canis, and Toxocara cati in Austria: a nationwide cross-sectional seroprevalence study.

Despite emerging risks for the spread of zoonotic diseases, data on human exposure to Echinococcus multilocularis and Toxocara spp., the causative parasites of the two most important helminthozoonoses in Central Europe, are limited. To investigate risk factors and exposure, we conducted a nationwide, cross-sectional serological study in 1046 healthy individuals, of which 425 were soldiers and 621 were civilians. Serum samples and information on possible risk factors for exposure, including previous foreign military assignments, residential area, animal contact, and regular outdoor activities, were obtained. Immunoglobulin G antibodies against Echinococcus multilocularis and Toxocara spp. were examined with an enzyme-linked immunosorbent assay (ELISA). Samples reactive in the ELISA for antibodies against Echinococcus multilocularis were considered positive only after confirmation by western blot. Overall, 66 (6.3%) individuals tested positive in the serologic screening for Toxocara spp. Occupational animal contact was the only risk factor significantly associated with a higher risk for being seropositive. None of the individuals were positive for antibodies against Echinococcus multilocularis. In conclusion, the present study demonstrates that exposure to Toxocara spp. is widespread in Austria and occupational animal contact is a risk factor for seropositivity.

High prevalence of antibodies against Leptospira spp. in male Austrian adults: a cross-sectional survey, April to June 2009.

To assess the distribution of specific antibodies against Leptospira spp. in Austrian adults, we conducted an explorative nationwide cross-sectional serological study in 400 healthy individuals. Antibody titres against Leptospira spp. were determined in a microscopic agglutination test using a panel of 14 serovar cultures. Sera of 18 participants were excluded because the samples were unsuitable for testing; the remaining 382 participants comprised 166 professional soldiers and 216 civilians. Overall, 88 (23%) individuals tested positive in serological screening. The subjects' sera reacted most frequently with serovars Canicola (16.5%) and Hardjo (11.8%). Epidemiological information was obtained from a questionnaire: no correlation was found for area of residence, travel abroad, regular outdoor activities, occupational animal contact, or ownership of companion animals. The proportion of seropositive samples was significantly lower among professional soldiers (15.7%) than among civilians (28.7%) (p=0.003). Our data demonstrate serological evidence of a high rate of exposure to Leptospira spp. among the Austrian population. No increased risk of exposure to Leptospira spp. was detected in military personnel.

In vitro activity of doripenem plus fosfomycin against drug-resistant clinical blood isolates.

The in vitro activity of doripenem in combination with fosfomycin was evaluated against a wide range of clinical blood isolates. Bacterial isolates of methicillin-resistant Staphylococcus aureus (MRSA; n = 39), Pseudomonas aeruginosa (n = 18), multidrug-resistant Escherichia coli (n = 10), Enterobacter cloacae (n = 3) and Klebsiella pneumoniae (n = 5) were investigated. For synergism testing the checkerboard test was applied and determined by calculation of the fractional inhibitory concentration index. Checkerboard results were verified by time-kill curve tests on selected isolates. Among MRSA, E. coli and K. pneumoniae, 94.9, 80 and 100% of isolates demonstrated synergism, respectively. Selected isolates demonstrated synergism in time-kill curve tests. P. aeruginosa isolates demonstrated no interaction in all isolates. Doripenem plus fosfomycin shows high efficacy with promising results in vitro.

Predictors of clinical and microbiological treatment failure in patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia: a retrospective cohort study in a region with low MRSA prevalence.

Invasive infections with methicillin-resistant Staphylococcus aureus (MRSA) have been associated with increased morbidity and mortality. The aim of the present study was to identify independent predictors of early mortality and treatment failure in patients with MRSA bacteraemia. A total of 132 adult patients who developed MRSA bacteraemia during hospitalization in the University Hospital of Vienna between 2000 and 2011 were screened and 124 were included in a retrospective cohort study. Patient demographics, source of bacteraemia, antimicrobial treatment and microbiological characteristics were evaluated. The 28-day crude mortality was 30.6%. Predictors of early mortality identified in multivariate Cox regression analysis included higher patient age (adjusted hazard ratio (aHR) 1.03, 95% CI 1.01-1.06, p 0.006), pneumonia (aHR 3.86, 95% CI 1.83-8.12, p <0.001) and failure to use MRSA active treatment (aHR 8.77, 95% CI 3.50-21.93, p <0.001). Ninety-one (73.4%) patients received glycopeptides as specific MRSA treatment. Of 63 patients treated with vancomycin, only 14 (22.6%) patients had aimed trough levels of 15-20 mg/L. Vancomycin MIC ≥2 mg/L was detected in 28.2% and was associated with glycopeptide pretreatment (p 0.001). All MRSA isolates were susceptible to linezolid and tigecycline. Persistent bacteraemia ≥7 days was documented in 25 (20.2%) patients. Independent determinants for microbiological eradication failure in patients with MRSA bacteraemia included endocarditis (p <0.001) and vancomycin trough levels (p 0.014), but not vancomycin MIC. Failure of clinical and microbiological eradication of MRSA among patients with MRSA bacteraemia was associated with clinical entity rather than with bacterial traits. Pharmacokinetic parameters seem to be decisive on microbiological and clinical success.

Seroprevalence and asymptomatic carriage of Leishmania spp. in Austria, a non-endemic European country.

Leishmaniasis is a rare disease in Central Europe and is diagnosed almost exclusively in travellers or migrants coming from tropical or subtropical countries. We conducted an explorative cross-sectional serological study, using a commercial ELISA, in 1048 healthy Austrian individuals to assess the distribution of specific antibodies against Leishmania spp. in humans in Austria. Overall, 47 individuals (4.5%) tested positive, and an additional 32 (3.1%) showed borderline results. After 12 months, sera from 42 of the 79 individuals who had initially tested seropositive/borderline were tested by ELISA a second time: 18 were persistently positive, nine were borderline. Those whose sera were persistently positive/borderline were then screened for potential carrier status using a commercial oligochromatographic PCR test to detect parasite DNA. Four samples were PCR positive and were subjected to a second PCR allowing parasite identification after DNA sequencing: two samples were identified as Leishmania donovani/infantum complex and Leishmania (Viannia) guyanensis, respectively. Epidemiological information was obtained with a questionnaire: no correlation was found for the number of holiday trips within the previous 6 months, but a significant risk of exposure to Leishmania spp. was found for travel to the New World, particularly to the Caribbean. Our data demonstrate that Leishmania spp. seroprevalence in non-endemic countries has been considerably underestimated.

Pre- and post-pandemic prevalence of antibodies to the 2009 pandemic influenza A (H1N1) virus in Austrian adults.

Antibody prevalence to the 2009 pandemic influenza A (H1N1) virus was determined in a sample of the Austrian population to assess the post-pandemic seropositivity rate, the infection attack rate, and the proportion of subclinical infections during the 2009/2010 influenza pandemic in Austrian adults. A total of 480 sera from individuals aged between 18 and 57 years from all nine federal states of Austria were collected between April and June 2010. Information on demographic characteristics, vaccination history, and history of suspected or verified influenza virus infection was ascertained. Antibodies were determined using a commercial ELISA and compared with 80 age-matched adult sera collected before the pandemic began. The overall seropositivity rate was 28% and was highest among young adults aged 18-29 years, followed by adults aged 50-57 years. Among seropositive unvaccinated individuals, infection was asymptomatic in more than 80%. Extrapolation to the overall Austrian adult population indicates that more than 1.3 million persons aged 18-57 years became infected in 2009. Compared with the pre-pandemic seropositivity rate, the infection rate was highest among young adults but low in those aged 30-57 years. Among 69 individuals previously vaccinated with the 2009 pandemic influenza A (H1N1) virus, 71% had specific antibodies. The study demonstrates that infection rates based on surveillance of clinical cases considerably underestimated the infection attack rate during the 2009 H1N1 pandemic in Austria and that vaccination against this virus elicited long-lasting seropositivity in more than 70% of adults.

Effectiveness and immunogenicity of pneumococcal vaccination in splenectomized and functionally asplenic patients.

The aim of the present study was to evaluate the effectiveness and immunogenicity of pneumococcal vaccination in 145 splenectomized and 2 functionally asplenic patients receiving the 23-valent pneumococcal polysaccharide vaccine and/or the 7-valent pneumococcal conjugate vaccine (PCV7) during the period 1996-2009. Progression of underlying malignant disease was the main cause of death in 68% of the 53 deceased patients, followed by septic shock in 13.2%. Twelve of 94 living patients developed post-vaccine complications: pneumonia in 9 patients, otitis media in 2, pneumococcal sepsis in 4. Compared with a non-splenectomized non-vaccinated control group (n=34), splenectomized patients vaccinated in the previous five years (n=15) had significantly higher GMCs (P<0.05) against serotypes 4, 6B, 9V, 14, 18C, 19F and 23F. Our data demonstrated strong serological responses in splenectomized patients within the first 5 years after pneumococcal vaccination by PCV7. Nevertheless, post-vaccine pneumococcal sepsis was still diagnosed in 3.3% of splenectomized survivors.

Comparative in vitro antimicrobial activity of vancomycin, teicoplanin, daptomycin and ceftobiprole in four different peritoneal dialysis fluids.

Peritoneal dialysis used in the treatment of patients with end-stage renal failure is often complicated by peritonitis. Staphylococcus aureus peritonitis is severe, particularly if caused by a methicillin-resistant strain (MRSA). Intraperitoneal administration of drugs for treatment of peritonitis is preferable to intravenous or oral routes because of the resulting higher local antibiotic concentrations. However, peritoneal dialysis fluids (PDFs) have a bacteriostatic effect, which may compromise the efficacy of antibiotics. The bactericidal efficacy of vancomycin, teicoplanin, daptomycin and ceftobiprole was studied in the PDFs Dianeal PD4® (glucose 1.36%), Physioneal 40® (glucose 1.36%), Extraneal® (7.5% icodextrin), and Nutrineal PD4® (1.1% amino acid) using time-kill curves. To simulate in vivo conditions, human serum albumin was added at a final concentration of 2 g/l. All four PDFs had a bacteriostatic effect on the growth of the MRSA test isolate. All antibiotics showed less activity in PDFs compared to control broth. Vancomycin and teicoplanin achieved the greatest reduction in bacterial numbers in the amino-acid containing PDF Nutrineal PD4®. Daptomycin showed its highest activity in Extraneal® and better overall efficacy than the other tested antibiotics. Ceftobiprole showed no killing activities in any of the four PDFs. Based on these in vitro data we conclude that the choice of PDFs for intraperitoneal administration is not trivial and could be crucial for therapy outcome.

Daptomycin, fosfomycin, or both for treatment of methicillin-resistant Staphylococcus aureus osteomyelitis in an experimental rat model.

The in vivo activities of daptomycin, fosfomycin, and a combination of both antibiotics against a clinical isolate of methicillin-resistant Staphylococcus aureus (daptomycin MIC, 0.25 µg/ml; fosfomycin MIC, 0.5 µg/ml) were evaluated in a rat model of osteomyelitis. A total of 37 rats with experimental osteomyelitis were treated for 4 weeks with either 60 mg/kg of body weight of daptomycin subcutaneously once daily, 75 mg/kg fosfomycin intraperitoneally once daily, a combination of both drugs, or a saline placebo. After the completion of treatment, animals were euthanized, and the infected tibiae were processed for quantitative bacterial culture. Bone cultures were found to be positive for methicillin-resistant S. aureus in 9 of 9 (100%) animals of the placebo group, in 9 of 9 (100%) animals treated with daptomycin, in 1 of 10 (10%) fosfomycin-treated rats, and in 1 of 9 (22.2%) rats comprising the combination group. Results of bacterial counts in the bone samples were expressed as log(10) CFU/g of bone and analyzed by using the Mann-Whitney U test followed by Bonferroni's multiple-comparison test. Based on bacterial counts, treatment with daptomycin was significantly superior to placebo, although it remained inferior to treatment with fosfomycin. No synergistic or antagonistic effect was observed for the combination therapy. No development of resistance against daptomycin or fosfomycin was observed after the 4-week treatment period.

Efficacy of fosfomycin in experimental osteomyelitis due to methicillin-resistant Staphylococcus aureus.

The activity of fosfomycin was evaluated in an experimental methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis model. Eighteen rats were treated for 4 weeks with 150 mg of fosfomycin/kg of body weight intraperitoneally once daily or with saline placebo. After treatment, animals were euthanized and the infected tibiae were processed for quantitative bacterial culture. Bone cultures were positive for methicillin-resistant S. aureus in all 9 (100%) untreated controls and in 2 of 9 (22.2%) fosfomycin-treated rats. Thus, fosfomycin treatment was significantly more efficacious than placebo. No development of resistance was observed after the 4-week treatment period.

In vitro antimicrobial activity of the novel polymeric guanidine Akacid plus.

The bactericidal and fungicidal activity of Akacid plus, a novel polymeric compound of the cationic family of disinfectants, was compared with chlorhexidine digluconate using quality control strains of Staphylococcus aureus, Enterococcus hirae, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. In vitro activity was determined using the quantitative suspension tests described by the European Committee for Standardization. These use concentrations of 0.01-0.5% against bacterial strains/C. albicans, with 0.5-4% against A. niger, and exposure times of 5, 15 and 60 min in the presence and absence of 0.3% bovine albumin and with dilution in distilled and hard water. In the basic quantitative suspension test, Akacid plus destroyed all bacterial pathogens at a concentration of 0.1% in < or =5 min. Chlorhexidine was also highly active against S. aureus, E. coli and P. aeruginosa, but failed to eliminate E. hirae within 5 min. A high organic load reduced the bactericidal activity of both disinfectants slightly. Akacid plus showed fungicidal activity against C. albicans within 15-60 min and eliminated A. niger at a concentration of 1% in 5 min of contact. Chlorhexidine was fungicidal against C. albicans, but not against A. niger.