Estimated Incidence of Hospitalizations and Deaths Attributable to Respiratory Syncytial Virus Infections Among Adults in Germany Between 2015 and 2019

INTRODUCTION

Respiratory syncytial virus (RSV) burden in adults is underestimated mainly due to unspecific symptoms and limited standard-of-care testing. We estimated the population-based incidence of hospitalization and mortality attributable to RSV among adults with and without risk factors in Germany.

METHODS

Weekly counts of hospitalizations and deaths for respiratory, cardiovascular, and cardiorespiratory diseases were obtained (Statutory Health Insurance database, 2015-2019). A quasi-Poisson regression model was fitted to estimate the number of hospitalizations and deaths attributable to RSV as a function of periodic and aperiodic time trends, and viral activity while allowing for potential overdispersion. Weekly counts of RSV and influenza hospitalizations in children < 2 years and adults ≥ 60 years, respectively, were used as viral activity indicators. Models were stratified by age group and risk status (defined as presence of selected comorbidities).

RESULTS

Population-based RSV-attributable hospitalization incidence rates were high among adults ≥ 60 years: respiratory hospitalizations (236-363 per 100,000 person-years) and cardiorespiratory hospitalizations (584-912 per 100,000 person-years). RSV accounted for 2-3% of all cardiorespiratory hospitalizations in this age group. The increase in cardiorespiratory hospitalization risk associated with underlying risk factors was greater in 18-44 year old persons (five to sixfold higher) than in ≥ 75 year old persons (two to threefold higher).

CONCLUSIONS

This is a first model-based study to comprehensively assess adult RSV burden in Germany. Estimated cardiorespiratory RSV hospitalization rates increased with age and were substantially higher in people with risk factors compared to those without risk factors. Our study indicates that RSV, like other respiratory viruses, contributes to both respiratory and cardiovascular hospitalizations. Effective prevention strategies are needed, especially among older adults ≥ 60 years and among adults with underlying risk factors.

[Invasive meningococcal disease: increased risk and vaccination prevention for immunocompromised patients]

BACKGROUND

The development of evidence-based guidelines for the prevention of infectious diseases through vaccination requires an understanding of populations that most likely may obtain an infection, severe illness or disease. Targeted vaccination recommendations are made possible by identifying risk groups, as is the case with meningococcal infections. Despite falling case numbers, meningococcal sepsis and meningococcal meningitis remain a major health problem.

METHOD

A systematic literature search was carried out on the research platform Ovid.

RESULTS

Vulnerable groups of people whose immune system is limited by primary and secondary immunodeficiency, such as asplenia, renal failure, human immunodeficiency virus (HIV) infection, diabetes, complement deficiency, organ and stem cell transplants, or immunomodulatory therapy (e.g., in rheumatic, hematological or oncological diseases), are exposed to an increased risk of infection and more severe courses of disease. Despite adequate medical care, the mortality rate is high and patients that survived the infection are often suffering from severe long-term sequelae. In such cases, the vaccination recommendations of the Standing Committee on Vaccination (STIKO) for indication vaccinations and the application instructions for vaccination in the case of immune deficiency should be consistently implemented in Germany.

CONCLUSIONS

Increased responsibility for comprehensive protection must be assumed for persons with underlying diseases. Reducing invasive meningococcal infections can be achieved through widespread education of patients and contacts, as well as practicing physicians on available vaccinations.

Did the change of the vaccination schedule effect pneumococcal conjugate vaccination compliance and adherence of premature and mature born infants in Germany? Answers from a claims database analysis

BACKGROUND

In August 2015, the German Standing Committee on Vaccination (STIKO) changed the pneumococcal conjugate vaccination (PCV) schedule for mature infants from a 3+1 to a 2+1scheme. For premature infants, the 3+1schedule remained unchanged. Aim was to assess vaccination rates, completeness, and timeliness for PCV stratified by premature and mature infants before and after the recommendation change based on real-world data.

METHODS

Retrospective claims data analyses were conducted using a comprehensive research database. The study population consisted of all mature and premature infants born in 2013, 2016, or 2018 with an individual follow-up of 24 months using ICD-10-GM codes P07.2 and P07.3 for premature infants. Hexavalent (HEXA) combination vaccination with a consistent 3+1recommendation for premature and mature infants was analyzed as a reference.

RESULTS

After follow-up of 24 months, rates of premature and mature infants receiving ≥1PCV and HEXA vaccination steadily increased since the change of STIKO's recommendation. However, in 2018 (2016/2013), only 47 % (41 %/65 %) of premature but 74 % (72 %/68 %) of mature infants obtained the recommended 3+1 respectively 2+1 PCV doses. At the same age, a consistent increase in complete HEXA vaccination with 3+1 doses was observed over time in premature (2013/2016/2018: 66 %/68 %/70 %) and mature (2013/2016/2018: 69 %/72 %/73 %) infants. Timeliness of PCV and HEXA booster administration remained stable with ∼50 % of all premature and mature infants receiving the booster according to recommended timelines.

CONCLUSION

There is no proven evidence that the reduced PCV schedule for mature infants induced a higher acceptance of vaccination. The rate of unvaccinated infants remained at a considerable level and vaccinations were often delayed. Although the STIKO still recommends a 3+1 PCV schedule for premature infants in Germany, less than half of children showed a completed vaccination series. To protect these vulnerable groups, efforts are needed to increase adherence to the STIKO recommendation especially for premature infants.

Epidemiology and Risk Factors of Clostridioides difficile Infections in Germany: A Health Claims Data Analysis

INTRODUCTION

Clostridioides difficile infection (CDI) is increasingly recognized as a public health threat at the community level in addition to being one of the most common causes of healthcare-associated infections. In Germany, the epidemiology of CDI is primarily informed by national hospital-based CDI surveillance. We used health claims data from Germany to obtain valuable insights on population-level disease burden and risk factors for CDI.

METHODS

This was a retrospective cohort study using a representative sample from the InGef research database. Overall and age- and sex-stratified CDI incidence rates were estimated for German adults from 2013 to 2017 using different case definitions (i.e., main, broad, strict), and further stratified by setting (inpatient versus outpatient). Risk factors for CDI were assessed for the 2013-2016 period.

RESULTS

The CDI incidence rate was high but declined by 15.3% from 2013 [141 (95% confidence interval, CI 137-145) cases/100,000 person-years] to 2017 [120 (95% CI 116-123)]. Annual CDI incidence rates were higher in female patients and the elderly. The most important risk factors for CDI were chronic inflammatory bowel disease [odds ratio (OR) 4.7, 95% CI 4.0-5.5], chemotherapy (OR 4.7, 95% CI 4.1-5.2), chronic kidney disease (OR 2.9, 95% CI 2.6-3.3), and ciprofloxacin receipt (OR 2.6, 95% CI 2.4-2.8).

CONCLUSIONS

Despite prevention strategies leading to declining incidence, CDI remains an important public health threat in Germany, with a high burden in the hospital setting and an outpatient epidemiology that is poorly understood. These findings, which are relevant both regionally and globally, can be used as a basis for further research on the full burden of CDI in Germany.

Cost-effectiveness of use of 20-valent pneumococcal conjugate vaccine among adults in Germany

OBJECTIVES

Despite national recommendations for use of pneumococcal vaccines, rates of community-acquired pneumonia (CAP) and invasive pneumococcal disease (IPD) remain high in Germany. New pneumococcal conjugate vaccines (PCVs) with expanded coverage have the potential to reduce the pneumococcal disease burden among adults.

METHODS

Using a Markov model, we evaluated the lifetime outcomes/costs comparing 20-valent PCV (PCV20) with standard of care (SC) vaccinations for prevention of CAP and IPD among adults aged ≥60 years and at-risk adults aged 18-59 years in Germany. PCV20 also was compared with sequential vaccination with 15-valent PCV (PCV15) followed by PPSV23 in a scenario analysis.

RESULTS

Over the course of a lifetime (82 years), use of PCV20vs. SC would prevent 54,333 hospitalizations, 26368 outpatient CAP cases, 10946 disease-related deaths yield 74,694 additional life-years (LYs), while lowering total medical costs by 363.2 M €. PCV20 remained cost saving (i.e. dominant) versus SC even in numerous sensitivity analyses, including a sensitivity analysis assuming moderate effectiveness of the SC pneumococcal polysaccharide vaccine against noninvasive pneumococcal CAP. In several scenario analyses and a probabilistic sensitivity analysis, PCV20 was also cost-saving compared toPCV15 PPSV23 vaccination.

CONCLUSIONS

One dose of PCV20 among adults aged ≥60 years and adults aged 18-59 years with moderate- and high-risk conditions wouldsubstantially reduce pneumococcal disease, save lives, and be cost saving compared with SC.

Frequency of Diarrhea, Stool Specimen Collection and Testing, and Detection of Clostridioides Difficile Infection Among Hospitalized Adults in the Muenster/Coesfeld Area, Germany

Clostridioides difficile infection (CDI) often manifests as diarrhea, particularly in adults of older age or with underlying comorbidities. However, only severe cases are notifiable in Germany. Moreover, failure to collect a stool specimen from inpatients with diarrhea or incomplete testing may lead to underdiagnosis and underreporting of CDI. We assessed the frequency of diarrhea, stool specimen collection, and CDI testing to estimate CDI underdiagnosis and underreporting among hospitalized adults. In a ten-day point-prevalence study (2019-2021) of nine hospitals in a defined area (Muenster/Coesfeld, North Rhine-Westphalia, Germany), all diarrhea cases (≥ 3 loose stools in 24 h) among adult inpatients were captured via medical record screening and nurse interviews. Patient characteristics, symptom onset, putative origin, antibiotic consumption, and diagnostic stool sampling were collected in a case report form (CRF). Diagnostic results were retrieved from the respective hospital laboratories. Among 6998 patients screened, 476 (7%) diarrhea patients were identified, yielding a hospital-based incidence of 201 cases per 10,000 patient-days. Of the diarrheal patients, 186 (39%) had a stool sample collected, of which 160 (86%) were tested for CDI, meaning that the overall CDI testing rate among diarrhea patients was 34%. Toxigenic C. difficile was detected in 18 (11%) of the tested samples. The frequency of stool specimen collection and CDI testing among hospitalized diarrhea patients was suboptimal. Thus, CDI incidence in Germany is likely underestimated. To assess the complete burden of CDI in German hospitals, further investigations are needed.

Pneumococcal vaccination rates in immunocompromised patients in Germany: A retrospective cohort study to assess sequential vaccination rates and changes over time

Background

Pneumococcal vaccination is recommended by the German Standing Committee on Vaccination (STIKO) for infants, elderly 60+ years and patients at risk. In 2016, a sequential pneumococcal vaccination schedule (conjugate vaccine followed by polysaccharide vaccine 6–12 months later) supplemented this recommendation for immunocompromised patients ≥2 years of age. Previous research showed low pneumococcal vaccination rates (pnc-VR) in this vulnerable group. Moreover, no evidence is available on adherence to the newer sequential schedule. This study aimed to analyze the development of pnc-VRs in immunocompromised patients and rates of sequential vaccinations according to the STIKO recommendations.

Methods

Using a representative health claims database, we assigned incident immunocompromised patients ≥2 years of age to one of two successive cohorts to observe trends over time: cohort A (first diagnosis of immunocompromised condition between 01/2013 and 12/2014), and cohort B (first diagnosis between 01/ 2015 and 12/2017). Pnc-VR within two years after first diagnosis and cumulative pnc-VR was compared among both cohorts. In cohort B, we assessed sequential pnc-VR within 15 months of the first vaccination. For additional analyses, patients were stratified by age, gender and immunocompromising condition.

Results

Cohort A and B comprised 193,521 and 289,279 patients, respectively. Overall pnc-VR increased over time from 4.3% (cohort A; 95%-confidence interval: 4.3%-4.4%) to 6.0% (cohort B; 5.9%-6.1%), with highest pnc-VRs in men ≥60 years (11.3%: 11.1%-11.6%) and HIV patients (15.2%: 13.1%-17.4%). Cumulative pnc-VRs in cohort B were higher in any quarter following diagnosis when compared with cohort A. Overall sequential pnc-VR in cohort B was 4.0% (3.7%-4.3%), with a higher rate observed in patients aged 16–59 (6.8%: 6.0%-7.7%) vs. patients aged ≥60 years (3.1%: 2.8%-3.4%).

Conclusion

While some improvements were seen over time, pnc-VRs remain very low in immunocompromised patients, as did sequential vaccination rates. Current recommendations to protect immunocompromised patients from pneumococcal infections are not being sufficiently implemented.

Vaccination rates and adherence in premature infants before and after pneumococcal conjugate vaccine schedule change for term infants - A claims database analysis in Germany

BACKGROUND

In 2015, the German Standing Committee on Vaccination (STIKO) changed the pneumococcal conjugate vaccination (PCV) schedule for mature infants from a 3+1scheme (2, 3, 4, and 11-14 months of age) to a 2+1scheme (2, 4, and 11-14 months of age). For premature infants, the 3+1scheme remained. The aim of this study was to assess vaccination rates, completeness, and timeliness for PCV in premature infants before and after the modified recommendation.

METHODS

A retrospective claims data analysis using the "Institut für angewandte Gesundheitsforschung Berlin" Research Database was conducted. Premature infants born in 2013 and 2016 with an individual follow-up of 24 months were included. Hexavalent combination (HEXA) vaccination with a consistent 3+1recommendation for mature and premature infants was analyzed as reference vaccination.

RESULTS

After 24 months, the PCV rate for at least one dose remained stable in premature newborns of 2016 compared to 2013, while the HEXA vaccination rate increased slightly. However, a significant decrease of a completed PCV schedule (4 doses) in premature infants was noted, whereas the completeness of HEXA vaccination did not change. The timeliness of PCV in premature newborns increased for the first and the booster PCV, while the timeliness of HEXA immunization did not change from 2013 to 2016.

CONCLUSION

Although STIKO still recommends a 3+1PCV schedule for premature infants in Germany, premature infants were vaccinated according to the changed recommendations for mature born infants. A substantial share of premature infants remained unvaccinated, and their vaccinations were often delayed.

Ticks on the turf: investigating the presence of ixodid ticks on and around football fields in Germany

Ixodes ricinus is the most abundant tick species and an important vector of pathogens in Germany and in large parts of Europe. A few other ixodid tick species, e.g., Dermacentor reticulatus, may also be of eco-epidemiological relevance. As ticks are not only found in natural but also in suburban areas (parks, gardens), the present study investigated whether ticks occur on and near football grounds thus posing a potential risk to players and visitors. Thirty-two football grounds from all 16 German federal states were selected, mainly situated adjacent to a green area (forest, park). Ticks were collected by the conventional flagging method in spring 2018, and nymphs and adults were counted and morphologically determined. Altogether 807 nymphal and adult ticks were collected from 29 football grounds: 714 I. ricinus, 64 Ixodes inopinatus, 2 Ixodes frontalis, 24 Ixodes sp. ticks, and 3 D. reticulatus. Ixodes inopinatus was found in 13 out of 16 German states. Three ticks were even found on the turf of two football fields. It can be concluded that ticks occur quite frequently and sometimes in high abundance near football grounds situated close or adjacent to a forest or a park.

Population-based incidence and mortality of community-acquired pneumonia in Germany

Background

Little information on the current burden of community-acquired pneumonia (CAP) in adults in Germany is available.

Methods

We conducted a retrospective cohort study using a representative healthcare claims database of approx. 4 million adults to estimate the incidence rates (IR) and associated mortality of CAP in 2015. IR and mortality were stratified by treatment setting, age group, and risk group status. A pneumonia coded in the primary diagnosis position or in the second diagnosis position with another pneumonia-related condition coded in the primary position was used as the base cases definition for the study. Sensitivity analyses using broader and more restrictive case definitions were also performed.

Results

The overall IR of CAP in adults ≥18 years was 1,054 cases per 100,000 person-years of observation. In adults aged 16 to 59 years, IR for overall CAP, hospitalized CAP and outpatient CAP was 551, 96 and 466 (with a hospitalization rate of 17%). In adults aged ≥60 years, the respective IR were 2,032, 1,061 and 1,053 (with a hospitalization rate of 52%). If any pneumonia coded in the primary or secondary diagnosis position was considered for hospitalized patients, the IR increased 1.5-fold to 1,560 in the elderly ≥60 years. The incidence of CAP hospitalizations was substantially higher in adults ≥18 years with at-risk conditions and high-risk conditions (IR of 608 and 1,552, respectively), compared to adults without underlying risk conditions (IR 108). High mortality of hospitalized CAP in adults ≥18 was observed in-hospital (18.5%), at 30 days (22.9%) and at one-year (44.5%) after CAP onset. Mortality was more than double in older adults in comparison to younger patients.

Conclusion

CAP burden in older adults and individuals with underlying risk conditions was high. Maximizing uptake of existing vaccines for respiratory diseases may help to mitigate the disease burden, especially in times of strained healthcare resources.

Vaccination rates and adherence in pneumococcal conjugate vaccination in mature born infants before and after vaccination schedule change - A claims database analysis

BACKGROUND

In August 2015, the German Standing Committee on Vaccination (STIKO) changed the pneumococcal conjugate vaccination (PCV) schedule for mature infants from a 3+1 scheme to a 2+1 scheme. It was expected that a reduction of doses would be associated with a higher acceptance of the vaccination. Aim of this study was to assess vaccination rates and adherence for PCV after the change of recommendation based on real-world data.

METHODS

A retrospective claims data analysis using the InGef Research Database was conducted. The study population consisted of all mature infants born in 2013 (last birth cohort completely under 3+1 recommendation) or 2016 (first birth cohort completely under 2+1 recommendation) with an individual follow-up of 24 months. Hexavalent combination vaccination (HEXA) with a consistent 3+1 recommendation was analyzed as reference.

RESULTS

After follow-up of 24 months, 90.9% (91.2%) of the 2016 (2013) cohort received at least one dose of PCV. At the same age, 67.7% of the 2013 cohort received a booster dose according to the 3+1 schedule and 75.6% of the 2016 cohort received a booster dose presumably either according to the 2+1 (71.7%) or 3+1 (3.9%) schedule. Of those receiving the booster dose, only 46.3% (2016) and 45.1% (2013) received the booster dose on time as recommended. The HEXA vaccination rate increased from 88.9% (2013) to 91.6% (2016) with a full series completion in 69.1% (2013) vs 72.9% (2016). The proportion of infants receiving the booster vaccination on time rose to 50.0% in 2016 (47.8% in 2013).

CONCLUSIONS

Although the rate for the PCV booster dose slightly increased, nearly a quarter of the infants born in 2016 did not receive a booster dose at all. Furthermore, vaccinations were still frequently delayed, and the rate of unvaccinated infants remained constant.

Vaccination rate and adherence of tick-borne encephalitis vaccination in Germany

BACKGROUND

Tick-borne encephalitis (TBE) is an arboviral infection of the central nervous system. As there is no causal treatment of TBE, disease prevention by vaccination is especially important. Immunization consists of a three-dose primary vaccination schedule, followed by regular booster doses. In Germany, the Standing Committee on Vaccination (STIKO) at the Robert Koch-Institute recommends TBE vaccination for all those at high risk of contracting TBE. This includes individuals living in, traveling to and/or working in risk areas, and being exposed to ticks. To our knowledge, there are currently no reliable data on TBE vaccination rates in Germany available.

METHODS

This retrospective cohort study based on anonymized German health claims data was conducted to determine vaccination rates of TBE primary immunization in 2012 to 2015 by federal state, compliance with the vaccination schedule, and TBE vaccination uptake for the 2011 birth cohort. Vaccination protection rates for each federal state were simulated based on a compartmental model.

RESULTS

Vaccination rates of an initiated primary immunization ranged from about 3% in the southern federal states to <1% in the northern federal states. Across all federal states, compliance with the vaccination schedule decreased with each subsequent vaccination. Slightly higher TBE vaccination uptake was determined in the 2011 birth cohort, as compared to the German school entry health examination statistics in 2017. Simulated vaccination protection rates for each federal state ranged from 10% in Hamburg to 51% in Baden-Wuerttemberg.

CONCLUSIONS

While there was an overall low vaccination uptake and a discrepancy between areas of high vs. low TBE risk, this study also indicates a concerning decline in vaccination compliance. Vaccinating physicians should address the importance of adherence upon initiation of TBE vaccination.

In Vitro Activity of the Bacteriophage Endolysin HY-133 against Staphylococcus aureus Small-Colony Variants and Their Corresponding Wild Types

Nasal carriage of methicillin-susceptible (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) represents both a source and a risk factor for subsequent infections. However, existing MRSA decolonization strategies and antibiotic treatment options are hampered by the duration of administration and particularly by the emergence of resistance. Moreover, beyond classical resistance mechanisms, functional resistance as the formation of the small-colony variant (SCV) phenotype may also impair the course and treatment of S. aureus infections. For the recombinant bacteriophage endolysin HY-133, rapid bactericidal and highly selective in vitro activities against MSSA and MRSA has been shown. In order to assess the in vitro efficacy of HY-133 against the SCV phenotype, minimal inhibitory (MIC) and minimal bactericidal concentrations (MBC) were evaluated on clinical SCVs, their isogenic wild types, as well as on genetically derived and gentamicin-selected SCVs. For all strains and growth phases, HY-133 MIC and MBC ranged between 0.12 and 1 mg/L. Time-kill studies revealed a fast-acting bactericidal activity of HY-133 resulting in a ≥3 - log10 decrease in CFU/mL within 1 h compared to oxacillin, which required 4⁻24 h. Since the mode of action of HY-133 was independent of growth phase, resistance pattern, and phenotype, it is a promising candidate for future S. aureus decolonization strategies comprising rapid activity against phenotypic variants exhibiting functional resistance.

The Energy-Coupling Factor Transporter Module EcfAA'T, a Novel Candidate for the Genetic Basis of Fatty Acid-Auxotrophic Small-Colony Variants of Staphylococcus aureus

Staphylococcal small-colony variants (SCVs) are invasive and persistent due to their ability to thrive intracellularly and to evade the host immune response. Thus, the course of infections due to this phenotype is often chronic, relapsing, and therapy-refractory. In order to improve treatment of patients suffering from SCV-associated infections, it is of major interest to understand triggers for the development of this phenotype, in particular for strains naturally occurring in clinical settings. Within this study, we comprehensively characterized two different Staphylococcus aureus triplets each consisting of isogenic strains comprising (i) clinically derived SCV phenotypes with auxotrophy for unsaturated fatty acids, (ii) the corresponding wild-types (WTs), and (iii) spontaneous in vitro revertants displaying the normal phenotype (REVs). Comparison of whole genomes revealed that clinical SCV isolates were closely related to their corresponding WTs and REVs showing only seven to eight alterations per genome triplet. However, both SCVs carried a mutation within the energy-coupling factor (ECF) transporter-encoding ecf module (EcfAA’T) resulting in truncated genes. In both cases, these mutations were shown to be naturally restored in the respective REVs. Since ECF transporters are supposed to be essential for optimal bacterial growth, their dysfunction might constitute another mechanism for the formation of naturally occurring SCVs. Another three triplets analyzed revealed neither mutations in the EcfAA’T nor in other FASII-related genes underlining the high diversity of mechanisms leading to the fatty acid-dependent phenotype. This is the first report on the ECF transporter as genetic basis of fatty acid–auxotrophic staphylococcal SCVs.

In Vitro Susceptibility of Clinical Staphylococcus aureus Small-Colony Variants to β-Lactam and Non-β-Lactam Antibiotics

The Staphylococcus aureus small-colony variant (SCV) phenotype has been associated with relapsing and antibiotic-refractory infections. However, little is known about the activities of antibiotics on clinical SCVs. Here, we demonstrated that SCVs without detectable auxotrophies were at least as susceptible to most β-lactam and non-β-lactam antibiotics in vitro as their corresponding clonally identical strains with a normal phenotype. After prolonged incubation, a regrowth phenomenon has been observed in gradient diffusion inhibition zones irrespective of the strains' phenotype.

Candida albicans and its metabolite gliotoxin inhibit platelet function via interaction with thiols

Platelets bind to Candida albicans, the major cause of candidiasis. But in contrast to other microorganisms the fungus does not aggregate platelets. Gliotoxin (GT), which possesses immunosuppressive properties, is produced by various fungi, including the opportunistic pathogens Aspergillus fumigatus and C. albicans. Its mode of action involves the formation of mixed disulfides with host proteins. Disulfide exchanges play an important role in platelet activation. Therefore, the effect of C. albicans and GT on platelet function was tested. C. albicans yeast cells (5,000–10,000 cells/μl) and GT, in pathophysiologically relevant concentrations (0.05–0.5 μM), inhibited platelet fibrinogen binding, anti gp IIb/IIIa antibody PAC-1 binding, aggregation and procoagulant activity in a dose-dependent manner. Alpha granule release, measured via CD62P surface expression, was not affected. Addition of reduced glutathione partially counteracted the effect of C. albicans and GT on platelet fibrinogen binding and platelet aggregation. The C. albicans metabolite GT features antithrombotic properties in addition to its immunosuppressive functions. Since treatment with reduced glutathione partially counteracted the inhibitory effect of C. albicans yeast cells and GT on platelet fibrinogen binding, the antithrombotic activity is likely to depend on the disulfide bridge of this mycotoxin. GT production by C. albicans could contribute to its survival in the blood stream during vascular infections. The knowledge of the underlying mechanisms of the antithrombotic properties might help to treat fungal infections as well as thrombosis.

Serum S100B Protein is Specifically Related to White Matter Changes in Schizophrenia

Background: Schizophrenia can be conceptualized as a form of dysconnectivity between brain regions.To investigate the neurobiological foundation of dysconnectivity, one approach is to analyze white matter structures, such as the pathology of fiber tracks. S100B is considered a marker protein for glial cells, in particular oligodendrocytes and astroglia, that passes the blood brain barrier and is detectable in peripheral blood. Earlier Studies have consistently reported increased S100B levels in schizophrenia. In this study, we aim to investigate associations between S100B and structural white matter abnormalities.

Methods: We analyzed data of 17 unmedicated schizophrenic patients (first and recurrent episode) and 22 controls. We used voxel based morphometry (VBM) to detect group differences of white matter structures as obtained from T1-weighted MR-images and considered S100B serum levels as a regressor in an age-corrected interaction analysis.

Results: S100B was increased in both patient subgroups. Using VBM, we found clusters indicating significant differences of the association between S100B concentration and white matter. Involved anatomical structures are the posterior cingulate bundle and temporal white matter structures assigned to the superior longitudinal fasciculus.

Conclusions: S100B-associated alterations of white matter are shown to be existent already at time of first manifestation of psychosis and are distinct from findings in recurrent episode patients. This suggests involvement of S100B in an ongoing and dynamic process associated with structural brain changes in schizophrenia. However, it remains elusive whether increased S100B serum concentrations in psychotic patients represent a protective response to a continuous pathogenic process or if elevated S100B levels are actively involved in promoting structural brain damage.

Staphylococcus aureus small colony variants show common metabolic features in central metabolism irrespective of the underlying auxotrophism

In addition to the classical phenotype, Staphylococcus aureus may exhibit the small colony-variant (SCV) phenotype, which has been associated with chronic, persistent and/or relapsing infections. SCVs are characterized by common phenotypic features such as slow growth, altered susceptibility to antibiotic agents and pathogenic traits based on increased internalization and intracellular persistence. They show frequently auxotrophies mainly based on two different mechanisms: (i) deficiencies in electron transport as shown for menadione- and/or hemin-auxotrophs and (ii) thymidylate biosynthetic-defective SCVs. To get a comprehensive overview of the metabolic differences between both phenotypes, we compared sets of clinically derived menadione-, hemin- and thymidine-auxotrophic SCVs and stable site directed mutants exhibiting the SCV phenotype with their corresponding isogenic parental strains displaying the normal phenotype. Isotopologue profiling and transcriptional analysis of central genes involved in carbon metabolism, revealed large differences between both phenotypes. Labeling experiments with [U-(13)C6]glucose showed reduced (13)C incorporation into aspartate and glutamate from all SCVs irrespective of the underlying auxotrophism. More specifically, these SCVs showed decreased fractions of (13)C2-aspartate and glutamate; (13)C3-glutamate was not detected at all in the SCVs. In comparison to the patterns in the corresponding experiment with the classical S. aureus phenotype, this indicated a reduced carbon flux via the citric acid cycle in all SCV phenotypes. Indeed, the aconitase-encoding gene (acnA) was found down-regulated in all SCV phenotypes under study. In conclusion, all SCV phenotypes including clinical isolates and site-directed mutants displaying the SCV phenotype were characterized by down-regulation of citric acid cycle activity. The common metabolic features in central carbon metabolism found in all SCVs may explain similar characteristics of the S. aureus SCVs irrespective of their auxotrophism as well as the specific genetic and/or regulatory backgrounds.

Staphylococcal disease in Africa: another neglected ‘tropical’ disease

The term ‘neglected tropical diseases’ predominantly refers to single-entity, mostly parasitic diseases. However, a considerable morbidity and mortality burden is carried by patients infected with Gram-positive cocci and Gram-negative bacilli that are prevalent all over the world, yet have impact in tropical and developing countries, particularly in children, with much higher incidence rates than those reported from developed countries. Staphylococcus aureus is among these pathogens. The African–German StaphNet consortium uses microbiological characterization of African S. aureus isolates, including identification of virulence factors, alongside the gathering of epidemiological and clinical data in an innovative research network between a European country (Germany) and several African partners. By creating an accessible strain repository and by implementing personnel training and capacity building, this network aims to put staphylococcal disease on the international agenda as a truly neglected condition with a major global impact on public health.

Streptococcus pneumoniae colonization in remote African Pygmies

BACKGROUND

African Pygmies have many risk factors for invasive pneumococcal disease (IPD), such as low socioeconomic status and low quality of health care. We characterized Streptococcus pneumoniae from Gabonese Pygmies and analyzed risk factors for S. pneumoniae carriage to improve prophylaxis and therapy of IPD in this neglected, remotely living African community.

METHODS

Nasopharyngeal carriage of S. pneumoniae, susceptibility, serotypes and risk factors for IPD were assessed in 103 Pygmies in a cross-sectional study.

RESULTS

The carriage rate was 37% (n = 38), with the highest proportion (79%, n = 11) in children between two and four years (n = 14). The predominant serotypes were 15A (24%, n = 9), 11A (16%, n = 6) and 6A (13%, n = 5). Non-susceptibility was detected against penicillin (Clinical and Laboratory Standards Institute; CLSI) meningitis breakpoints; (18%, n = 7), trimethoprim/sulfamethoxazole (61%, n = 23), tetracycline (55%, n = 21) and chloramphenicol (3%, n = 1). Among adult participants (n = 51), 69% (n = 35) regularly consumed alcohol and 75% (n = 38) reported to smoke cigarettes.

CONCLUSION

The high proportion of nicotine and drug abuse might increase the risk of IPD. The unusual serotypes challenge a broad coverage by currently marketed vaccines; the broad antibiotic resistance limits the choice of therapy for S. pneumoniae infection.

Therapy of 1,025 severely ill patients with complicated infections in a German multicenter study: safety profile and efficacy of tigecycline in different treatment modalities

This large prospective non-interventional study investigated the effects of tigecycline either as single agent or in combination with other antimicrobial agents in 1,025 patients treated in clinical routine at German hospitals. Sixty-five percent of the patients had APACHE II scores > 15, indicating high overall disease severity. Complicated intra-abdominal infections (cIAI) or complicated skin and skin tissue infections (cSSTI) were the most common indications, with Staphylococcus aureus, Enterococcus faecium and Escherichia coli being the most frequently isolated pathogens. Clinical success was reported at the end of tigecycline therapy in 74.2% of the total population, in 75.4% of the cIAI and in 82.2% of the cSSTI patients. The subpopulation (28.0% of the patients) infected with multidrug-resistant pathogens (methicillin-resistant S. aureus, extended-spectrum β-lactamase producers and vancomycin-resistant enterococci) were treated with similar success rates as the overall population. Tigecycline was generally well tolerated. Drug-related adverse events (AEs) were reported in 7.7% of the total population; 2.5% had serious AEs mostly attributable to inefficacy of therapy or deterioration of the disease. Mortality rates were consistent with the types of infection and severity of illness. There was no indication of excessive mortality associated with tigecycline as had been suggested in previously performed meta-analyses. In this large non-interventional study performed in the clinical routine setting, tigecycline achieved favorable clinical success rates in a patient population with high severity of illness and a high prevalence of multidrug-resistant pathogens and showed a good safety and tolerability profile.

Susceptibility of Staphylococcus aureus bacteremia strains to different skin-derived antimicrobial proteins

Staphylococcus aureus is a major human pathogen causing cutaneous infections to life-threatening bacteremia. These infections are often caused by strains derived from the own microflora suggesting that a disturbed epidermal barrier may promote invasion of S. aureus. Antimicrobial peptides and proteins (AMP) such as human beta-defensin-3 and RNase 7 contribute to control the colonization of S. aureus on the skin surface. This leads to the hypothesis that strains with a decreased susceptibility toward skin-derived AMP may better overcome the innate cutaneous defence barrier increasing the possibility of invading into the blood stream. To address this hypothesis we determined whether S. aureus strains from bacteremia patients are less susceptible to various skin-derived AMP than strains from healthy carriers. No differences in the AMP-killing activity against bacteremia-derived S. aureus and control strains were detected suggesting that the onset of S. aureus bacteremia is not based on the varying susceptibilities against skin-derived AMP.

Nasal carriage as a source of agr-defective Staphylococcus aureus bacteremia

Inactivating mutations in the Staphylococcus aureus virulence regulator agr are associated with worse outcomes in bacteremic patients. However, whether agr dysfunction is primarily a cause or a consequence of early bacteremia is unknown. Analysis of 158 paired S. aureus clones from blood and nasal carriage sites in individual patients revealed that recovery of an agr-defective mutant from blood was usually predicted by the agr functionality of carriage isolates. Many agr-positive blood isolates produced low levels of hemolytic toxins, but levels were similar to those of colonizing strains within patients, suggesting that introduction into the blood did not select for mutations with minor functional effects. Evidently, the transition from commensalism to opportunism in S. aureus does not require full virulence in hospitalized patients. Furthermore, agr-defective mutants were found in uninfected nasal carriers in the same proportion as in carriers who develop bacteremia, suggesting low correlation between virulence and infectivity.

Catheter colonization and abscess formation due to Staphylococcus epidermidis with normal and small-colony-variant phenotype is mouse strain dependent

Coagulase-negative staphylococci (CoNS) form a thick, multilayered biofilm on foreign bodies and are a major cause of nosocomial implant-associated infections. Although foreign body infection models are well-established, limited in vivo data are available for CoNS with small-colony-variant (SCV) phenotype described as causative agents in implant-associated infections. Therefore, we investigated the impact of the Staphylococcus epidermidis phenotype on colonization of implanted PVC catheters and abscess formation in three different mouse strains. Following introduction of a catheter subcutaneously in each flank of 8- to 12-week-old inbred C57BL/6JCrl (B6J), outbred Crl:CD1(ICR) (CD-1), and inbred BALB/cAnNCrl (BALB/c) male mice, doses of S. epidermidis O-47 wild type, its hemB mutant with stable SCV phenotype, or its complemented mutant at concentrations of 10(6) to 10(9) colony forming units (CFUs) were gently spread onto each catheter. On day 7, mice were sacrificed and the size of the abscesses as well as bacterial colonization was determined. A total of 11,500 CFUs of the complemented mutant adhered to the catheter in BALB/c followed by 9,960 CFUs and 9,900 CFUs from S. epidermidis wild type in BALB/c and CD-1, respectively. SCV colonization was highest in CD-1 with 9,500 CFUs, whereas SCVs were not detected in B6J. The minimum dose that led to colonization or abscess formation in all mouse strains was 10(7) or 10(8) CFUs of the normal phenotype, respectively. A minimum dose of 10(8) or 10(9) CFU of the hemB mutant with stable SCV phenotype led to colonization only or abscess formation, respectively. The largest abscesses were detected in BALB/c inoculated with wild type bacteria or SCV (64 mm(2) vs. 28 mm(2)). Our results indicate that colonization and abscess formation by different phenotypes of S. epidermidis in a foreign body infection model is most effective in inbred BALB/c followed by outbred CD-1 and inbred B6J mice.

Effect of low temperature on growth and ultra-structure of Staphylococcus spp

The effect of temperature fluctuation is an important factor in bacterial growth especially for pathogens such as the staphylococci that have to remain viable during potentially harsh and prolonged transfer conditions between hosts. The aim of this study was to investigate the response of S. aureus, S. epidermidis, and S. lugdunensis when exposed to low temperature (4°C) for prolonged periods, and how this factor affected their subsequent growth, colony morphology, cellular ultra-structure, and amino acid composition in the non-cytoplasmic hydrolysate fraction. Clinical isolates were grown under optimal conditions and then subjected to 4°C conditions for a period of 8 wks. Cold-stressed and reference control samples were assessed under transmission electron microscopy (TEM) to identify potential ultra-structural changes. To determine changes in amino acid composition, cells were fractured to remove the lipid and cytoplasmic components and the remaining structural components were hydrolysed. Amino acid profiles for the hydrolysis fraction were then analysed for changes by using principal component analysis (PCA). Exposure of the three staphylococci to prolonged low temperature stress resulted in the formation of increasing proportions of small colony variant (SCV) phenotypes. TEM revealed that SCV cells had significantly thicker and more diffuse cell-walls than their corresponding WT samples for both S. aureus and S. epidermidis, but the changes were not significant for S. lugdunensis. Substantial species-specific alterations in the amino acid composition of the structural hydrolysate fraction were also observed in the cold-treated cells. The data indicated that the staphylococci responded over prolonged periods of cold-stress treatment by transforming into SCV populations. The observed ultra-structural and amino acid changes were proposed to represent response mechanisms for staphylococcal survival amidst hostile conditions, thus maintaining the viability of the species until favourable conditions arise again.

Functional assessment of a promoter polymorphism in S100B, a putative risk variant for bipolar disorder

Calcium-binding protein S100B has been implicated in the pathology of bipolar affective disorder (BPAD) and schizophrenia (SZ). S100B protein levels are elevated in serum of patients with both disorders compared to controls. We previously reported genetic association of a SNP in the promoter of S100B, rs3788266, with a psychotic form of BPAD. To test for genotypic effects of rs3788266 in vivo, S100B serum protein levels were measured in 350 Irish and German subjects of known S100B genotype. The functional effect of rs3788266 on S100B promoter activity was studied using the luciferase reporter system in U373MG glioblastoma and SH-SY5Y neuroblastoma cell lines. Allelic effects of rs3788266 on protein complex formation at the S100B promoter were investigated by an electrophoretic mobility shift assay. Higher mean serum S100B levels were associated with the risk G allele of rs3788266 in BPAD cases (P = 0.0001), unaffected relatives of BPAD cases (P < 0.0001) and unrelated controls (P < 0.0001). Consistent with the in vivo findings, luciferase gene expression was significantly increased in the presence of the G allele compared to the A allele in SH-SY5Y (P = <0.0001), and in U373MG (P = <0.0008) cell lines. The binding affinity of both SH-SY5Y and U373MG protein complexes for the S100B promoter was significantly stronger in the presence of G allele compared to the A allele promoter fragments. These data support rs3788266 as a functional promoter variant in the S100B gene where the presence of the G allele promotes increased gene expression and is associated with increased serum levels of the protein.

In vitro activity against Staphylococcus aureus of a novel antimicrobial agent, PRF-119, a recombinant chimeric bacteriophage endolysin

Antistaphylococcal activity of the novel chimeric endolysin PRF-119 was evaluated with the microdilution method. The MIC(50) and MIC(90) of 398 methicillin-susceptible Staphylococcus aureus isolates were 0.098 μg/ml and 0.391 μg/ml, respectively (range, 0.024 to 0.780 μg/ml). Both the MIC(50) and MIC(90) values of 776 methicillin-resistant S. aureus isolates were 0.391 μg/ml (range, 0.024 to 1.563 μg/ml). All 192 clinical isolates of coagulase-negative staphylococci exhibited MIC values of >50 μg/ml. In conclusion, PRF-119 exhibited very good activity specifically against S. aureus.

Genomic and proteomic characterization of Staphylococcus aureus mastitis isolates of bovine origin

Staphylococcus aureus colonizes and infects humans as well as animals. In the present study, 17 S. aureus strains isolated from cows suffering from mastitis were characterized. The well-established multilocus sequence typing (MLST) technique and a diagnostic microarray covering 185 S. aureus virulence and resistance genes were used for genetic and epidemiological analyses. Virulence gene expression studies were performed by analyzing the extracellular protein pattern of each isolate on 2-D gels. By this way, a pronounced heterogeneity of the extracellular proteome between the bovine isolates has been observed which was attributed to genome plasticity and variation of gene expression. Merely 12 proteins were expressed in at least 80% of the isolates, i.e. Atl, Aur, GlpQ, Hla, LtaS, Nuc, PdhB, SAB0846, SAB2176, SAB0566, SspA, and SspB forming the core exoproteome. Fifteen extracellular proteins were highly variably expressed and only present in less than 20% of the isolates. This includes the serine proteases SplB, C, and F, and the superantigens SEC-bov, SEL and TSST-1. Compared to human isolates we identified at least six proteins with significantly different expression frequencies. While SAB0846 was expressed more frequently in bovine isolates, LytM, EbpS, Spa, Geh, and LukL1 were seen less frequently in these isolates.

Population structure of Staphylococcus aureus from remote African Babongo Pygmies

Background

Pandemic community-acquired methicillin-resistant Staphylococcus aureus isolates (CA-MRSA) predominantly encode the Panton-Valentine leukocidin (PVL), which can be associated with severe infections. Reports from non-indigenous Sub-Saharan African populations revealed a high prevalence of PVL-positive isolates. The objective of our study was to investigate the S. aureus carriage among a remote indigenous African population and to determine the molecular characteristics of the isolates, particularly those that were PVL-positive.

Methodology/Principal Findings

Nasal S. aureus carriage and risk factors of colonization were systematically assessed in remote Gabonese Babongo Pygmies. Susceptibility to antibiotics, possession of toxin-encoding genes (i.e., PVL, enterotoxins, and exfoliative toxins), S. aureus protein A (spa) types and multi-locus sequence types (MLST) were determined for each isolate. The carriage rate was 33%. No MRSA was detected, 61.8% of the isolates were susceptible to penicillin. Genes encoding PVL (55.9%), enterotoxin B (20.6%), exfoliative toxin D (11.7%) and the epidermal cell differentiation inhibitor B (11.7%) were highly prevalent. Thirteen spa types were detected and were associated with 10 STs predominated by ST15, ST30, ST72, ST80, and ST88.

Conclusions

The high prevalence of PVL-positive isolates among Babongo Pygmies demands our attention as PVL can be associated with necrotinzing infection and may increase the risk of severe infections in remote Pygmy populations. Many S. aureus isolates from Babongo Pygmies and pandemic CA-MRSA-clones have a common genetic background. Surveillance is needed to control the development of resistance to antibiotic drugs and to assess the impact of the high prevalence of PVL in indigenous populations.

Staphylococcus aureus is a bacterium that colonizes humans worldwide. The anterior nares are its main ecological niche. Carriers of S. aureus are at a higher risk of developing invasive infections. Few reports indicated a different clonal structure and profile of virulence factors in S. aureus isolates from Sub-Saharan Africa. As there are no data about isolates from remote indigenous African populations, we conducted a cross-sectional survey of S. aureus nasal carriage in Gabonese Babongo Pygmies. The isolates were characterized regarding their susceptibility to antibiotic agents, possession of virulence factors and clonal lineage. While similar carriage rates were found in populations of industrialized countries, isolates that encode the genes for the Panton-Valentine leukocidin (PVL) were clearly more prevalent than in European countries. Of interest, many methicillin-susceptible S. aureus isolates from Babongo Pygmies showed the same genetic background as pandemic methicillin-resistant S. aureus (MRSA) clones. We advocate a surveillance of S. aureus in neglected African populations to control the development of resistance to antibiotic drugs with particular respect to MRSA and to assess the impact of the high prevalence of PVL-positive isolates.

The matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS)-based protein peaks of 4448 and 5302 Da are not associated with the presence of Panton-Valentine leukocidin

The Panton-Valentine leukocidin (PVL) of Staphylococcus aureus plays an important role in the pathogenesis of necrotizing pneumonia and recurrent skin and soft tissue infections. The gene encoding for PVL, lukS/F-PV, is distributed by prophages and can thus spread between isolates. Molecular methods have normally been used to identify lukS/F-PV-positive strains. Recently, however, a matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS)-based method has been described to identify PVL-positive S. aureus strains. The aim of this study was thus to investigate the association of distinct MALDI-TOF MS peaks to the toxin profile in molecularly characterized methicillin-susceptible (MSSA) and methicillin-resistant S. aureus (MRSA) strains harbouring lukS/F-PV. In contrast to the previous results, the MALDI-TOF MS peaks were detected in all 104 recently described molecularly divergent MRSA irrespective of the presence of PVL. Our result indicates that these described peaks seem to be independent of the presence of PVL.

Reduction of periprosthetic infection with silver-coated megaprostheses in patients with bone sarcoma

BACKGROUND AND OBJECTIVES

The placement of megaprostheses in patients with bone sarcoma is associated with high rates of infection, despite prophylactic antibiotic administration. In individual cases, secondary amputation is unavoidable in the effort to cure infection.

METHODS

The infection rate in 51 patients with sarcoma (proximal femur, n = 22; proximal tibia, n = 29) who underwent placement of a silver-coated megaprosthesis was assessed prospectively over a 5-year period, along with the treatment administered for infection. The infection rate was compared with the data for 74 patients in whom an uncoated titanium megaprosthesis (proximal femur, n = 33; proximal tibia, n = 41) was implanted.

RESULTS

The infection rate was substantially reduced from 17.6% in the titanium to 5.9% in the silver group. Whereas 38.5% of patients in the titanium group ultimately had to undergo amputation when periprosthetic infection developed, these mutilating surgical procedures were not necessary in the study group.

CONCLUSIONS

The use of silver-coated prostheses reduced the infection rate in the medium term. In addition, less aggressive treatment of infection was possible in the group with silver-coated prostheses. Further studies with longer term follow-up periods and larger numbers of patients are warranted in order to confirm these encouraging results.

Redox sensing by a Rex-family repressor is involved in the regulation of anaerobic gene expression in Staphylococcus aureus

An alignment of upstream regions of anaerobically induced genes in Staphylococcus aureus revealed the presence of an inverted repeat, corresponding to Rex binding sites in Streptomyces coelicolor. Gel shift experiments of selected upstream regions demonstrated that the redox-sensing regulator Rex of S. aureus binds to this inverted repeat. The binding sequence – TTGTGAAW₄TTCACAA – is highly conserved in S. aureus. Rex binding to this sequence leads to the repression of genes located downstream. The binding activity of Rex is enhanced by NAD⁺ while NADH, which competes with NAD⁺ for Rex binding, decreases the activity of Rex. The impact of Rex on global protein synthesis and on the activity of fermentation pathways under aerobic and anaerobic conditions was analysed by using a rex-deficient strain. A direct regulatory effect of Rex on the expression of pathways that lead to anaerobic NAD⁺ regeneration, such as lactate, formate and ethanol formation, nitrate respiration, and ATP synthesis, is verified. Rex can be considered a central regulator of anaerobic metabolism in S. aureus. Since the activity of lactate dehydrogenase enables S. aureus to resist NO stress and thus the innate immune response, our data suggest that deactivation of Rex is a prerequisite for this phenomenon.

Risk variants in the S100B gene predict elevated S100B serum concentrations in healthy individuals

Several lines of evidence suggest an important role of the S100B protein and its coding gene in different neuropathological and psychiatric disorders like dementia, bipolar affective disorders and schizophrenia. To clarify whether a direct link exists between gene and gene product, that is, whether S100B variants directly modulate S100B serum concentration, 196 healthy individuals were assessed for S100B serum concentrations and genotyped for five potentially functional S100B SNPs. Functional variants of the serotonergic genes 5-HT1A and 5-HTT possibly modulating S100B serum levels were also studied. Further, publicly available human postmortem gene expression data were re-analyzed to elucidate the impact of S100B, 5-HT1A and 5-HTT SNPs on frontal cortex S100B mRNA expression. Several S100B SNPs, particularly rs9722, and the S100B haplotype T-G-G-A (including rs2186358-rs11542311-rs2300403-rs9722) were associated with elevated S100B serum concentrations (Bonferroni corrected P < 0.05). Of these, rs11542311 was also associated with S100B mRNA expression directly (Bonferroni corrected P = 0.05) and within haplotype G-A-T-C (rs11542311-rs2839356-rs9984765-rs881827; P = 0.004), again with the G-allele increasing S100B expression. Our results suggest an important role of S100B SNPs on S100B serum concentrations and S100B mRNA expression. It hereby links recent evidence for both, the impact of S100B gene variation on various neurological or psychiatric disorders like dementia, bipolar affective disorders and schizophrenia and the strong relation between S100B serum levels and these disorders.

Energy-dependent stimulatory and inhibitory effects of extracorporeal shock waves on bacteria and on gentamicin activity

BACKGROUND

Local infection is considered a contraindication for extracorporeal shock wave (ESW) application, although the antibacterial effects of ESW have been clearly demonstrated in vitro. This study aimed to assess the effects of ESW on bacteria under growth-promoting conditions and to evaluate interactions with the activity of gentamicin.

MATERIAL/METHODS

Standardized suspensions of Staphylococcus aureus were exposed to 4000 shock wave impulses of various energy flux densities (EFD) both at 37 degrees C in growth medium and at 20 degrees C in saline. Bacterial viability of treatment groups and controls were quantified. Furthermore, the MICs of gentamicin against ESW-treated and untreated suspensions of S. aureus were compared. Finally, suspensions of S. aureus containing graded concentrations of gentamicin were exposed to ESW and bacterial growth was assessed.

RESULTS

Antibacterial effects of ESW (0.59-0.96 mJ/mm2) were confirmed with bacteria suspended in normal saline (20 degrees C, p<0.05). However, bacteria suspended in growth medium at 37 degrees C demonstrated significantly increased proliferation (p=0.009) after treatment with shock waves of lower EFD (0.59 mJ/mm2). At higher EFD a significant reduction of bacteria was observed (p=0.009). The MIC of gentamicin against S. aureus was not altered by ESW application. Furthermore, the combination of gentamicin and ESW did not alter gentamicin activity (p>0.05). Nevertheless, a growth-promoting effect of ESW at 0.59 mJ/mm(2) was demonstrated despite simultaneous administration of gentamicin.

CONCLUSIONS

This is the first study reporting energy-dependent stimulation of bacterial growth by ESW. Also important is that ESW did not alter the activity of gentamicin.

Safety and effectiveness of extracorporeal shockwave therapy: results of a rabbit model of chronic osteomyelitis

Extracorporeal shockwave therapy (ESWT) is applied successfully in various orthopedic disorders. Since shockwaves have demonstrated significant bactericidal effectiveness in vitro, safety and effectiveness of ESWT in vivo were evaluated in a rabbit model of osteomyelitis. Chronic osteomyelitis was induced by injecting sodium morrhuate and Staphylococcus aureus into the proximal tibia of 12 New Zealand white rabbits. Four and five wk after the initial operation, soft focused ESWT was applied twice to the infected limbs. Clinical parameters and laboratory values were followed and blood samples were taken for culture before and 30 min after ESWT. Following sacrifice after 8 wk, lungs, spleen and kidneys were studied histologically for signs of sepsis and secondary infection. Tibial osteomyelitis was assessed clinically, and by radiologic, microbiologic and histologic procedures. Signs of bacterial spreading were not detectable after ESWT, neither in blood cultures nor in histologic analyses of representative organs. Temperature, body weight, C-reactive protein and white blood cell levels also remained unchanged after ESWT. Of particular interest, histologic scores of osteomyelitis were significantly decreased in the ESWT-group compared to the untreated control (p = 0.019). However, S. aureus was still detectable in tissue samples of all animals. This is the first study investigating the effects of ESWT applied to infected target areas. ESWT of infected bone did neither induce bacterial spreading nor worsening of infection, and the results suggest the reported treatment protocol of ESWT to be beneficial in the treatment of chronic bone infections.

Memory impairment correlates with increased S100B serum concentrations in patients with chronic schizophrenia

Astrocyte activation indicated by increased S100B is considered a potential pathogenic factor for schizophrenia. To investigate the relationship between astrocyte activation and cognitive performance, S100B serum concentration, memory performance, and psychopathology were assessed in 40 first-episode and 35 chronic schizophrenia patients upon admission and after four weeks of treatment. Chronic schizophrenia patients with high S100B were impaired concerning verbal memory performance (AVLT, Auditory Verbal Learning Test) compared to chronic and first-episode patients with low S100B levels. The findings support the hypothesis that astrocyte activation might contribute to the development of cognitive dysfunction in schizophrenia.

Human platelets attenuate Aspergillus species via granule-dependent mechanisms

Using laser scanning microscopy, we investigated whether platelets are capable of internalizing Aspergillus conidia and examined Aspergillus-platelet adherence. The influence of platelets on fungal growth was evaluated by assessing galactomannan (GM) release, hyphal elongation, and colony size. A secretion assay with [(3)H]-serotonin (5-hydroxytryptamine [5-HT]) was performed. Exposure to platelets resulted in significantly decreased GM release (p<.05), hyphal elongation (p<.001), colony size, pigmentation, and 5-HT release ( p<.05). A lack of antifungal effects was observed with the microfilament inhibitor cytochalasin D. Platelets attenuate the virulence of Aspergillus species in vitro on the basis of granule-dependent effects.

Kytococcus schroeteri: a probably underdiagnosed pathogen involved in prosthetic valve endocarditis

Kytoccoccus schroeteri is an emerging pathogen found mainly in association with prosthetic valve endocarditis. A striking aspect of this species is its resistance to penicillins, including isoxazolylpenicillins, making glycopeptide administration and valve replacement the treatment of choice. We present the case of a 38-year-old female diabetic patient with fever up to 39.1 degrees C for two months. Infection of her prosthetic aortic valve was suspected clinically. Repeated blood cultures revealed growth of K. schroeteri. Transesophageal echocardiography demonstrated a vegetation on the prosthetic aortic valve. Antibiotic treatment with vancomycin, rifampin and gentamicin was started and this regimen led to complete resolution of symptoms and disappearance of the vegetation. It is of particular interest that the patient recovered without further surgical procedures. Since the first description of K. schroeteri in 2002, four cases of endocarditis have been published, suggesting antecedent and continuing underdiagnosis.

Microbiological evaluation of a new growth-based approach for rapid detection of methicillin-resistant Staphylococcus aureus

Objectives

Recently, a rapid screening tool for methicillin-resistant Staphylococcus aureus (MRSA) has been introduced that applies a novel detection technology allowing the rapid presence or absence of MRSA to be determined from an enrichment broth after only a few hours of incubation. To evaluate the reliability of this new assay to successfully detect MRSA strains of different origin and clonality, well-characterized S. aureus strains were tested in this study.

Methods

More than 700 methicillin-susceptible and methicillin-resistant strains covering >90% of all registered European MRSA spa types within the SeqNet network were studied.

Results

All 513 MRSA strains tested were recognized as methicillin-resistant: among these, 96 MRSA strains were from an institutional collection, each presenting a unique spa type. None of the 211 methicillin-susceptible strains were detected as positive.

Conclusions

The new growth-based rapid MRSA assay was shown to detect without exception all MRSA strains of large collections of strains comprising highly diverse genetic backgrounds, indicating that such a phenotypic test might be potentially more likely to cope with new strains.

Resistance of chemokine receptor 6-deficient mice to Yersinia enterocolitica infection: evidence of defective M-cell formation in vivo

M cells, specialized cells within Peyer's patches (PPs), are reduced in number in chemokine receptor 6 (CCR6)-deficient mice. The pathogenic microorganism Yersinia enterocolitica exploits M cells for the purpose of mucosal tissue invasion exclusively through PPs. The aim of this study was to evaluate the course of yersiniosis in CCR6-deficient mice and to investigate whether these mice might be used as an in vivo model to determine M-cell function. After oral challenge with Y. enterocolitica, control mice suffered from lethal septic infection whereas CCR6-deficient mice showed very limited symptoms of infection. Immunohistochemical analysis demonstrated PP invasion by Y. enterocolitica in control mice whereas no bacteria could be found in CCR6-deficient mice. In addition, a significant induction of proinflammatory cytokines could be found in control mice whereas proinflammatory cytokine levels in CCR6-deficient mice remained unchanged. In contrast, intraperitoneal infection resulted in severe systemic yersiniosis in both mouse groups. Abrogated oral Y. enterocolitica infection in CCR6-deficient mice demonstrates the importance of CCR6 expression in the physiological and pathological immune responses generated within PPs by influencing M-cell differentiation, underscoring the important role of M cells in the process of microbial uptake. CCR6-deficient mice may therefore represent a suitable model for the study of M-cell function in vivo.

Understanding the physiology and adaptation of staphylococci: A post-genomic approach

Staphylococcus aureus as well as coagulase-negative staphylococci are medically highly important pathogens characterized by an increasing resistance rate toward many antibiotics. Although normally being skin and mucosa commensals, some staphylococcal species and strains have the capacity to cause a wide range of infectious diseases. Many of these infections affect immunocompromised patients in hospitals. However, community-acquired staphylococcal infections due to resistant strains are also currently on the rise. In the light of this development, there is an urgent need for novel anti-staphylococcal therapeutic and prevention strategies for which a better understanding of the physiology of these bacteria is an essential prerequisite. Within the past years, staphylococci have been in the focus of genomic research, resulting in the determination and publication of a range of full-genome sequences of different staphylococcal species and strains which provided the basis for the design and application of DNA microarrays and other genomic tools. Here we summarize the results of the project group 'Staphylococci' within the research network 'Pathogenomics' giving new insights into the genome structure, molecular epidemiology, physiology, and genetic adaptation of both S. aureus and coagulase-negative staphylococci.