Comparative analysis of RSV-related hospitalisations in children and adults over a 7 year-period before, during and after the COVID-19 pandemic

BACKGROUND

RSV is an important cause for respiratory illness in children and the elderly. We analysed RSV seasons since 2016 in both age groups for differences, similarities and timely associations before, during and after the COVID-19 pandemic.

METHODS

We studied epidemiological and clinical features of seven consecutive RSV seasons since 2016 retrospectively in children and adults who were systematically monitored for RSV infections by PCR when hospitalized in Regensburg, Germany.

RESULTS

Data from 1903 RSV positive, hospitalised patients were analysed (1446 children, 457 adults). We observed a complete absence of RSV associated hospitalizations in season 2020/2021. While in the season of 2021/2022, RSV associated hospitalizations in children returned to considerable numbers earlier than expected, hospitalizations in the elderly were still mitigated during that season in temporal association with the continuation of NPI measures for COVID-19 in the elderly until summer of 2022. Overall, children were hospitalized more often for RSV, while the elderly showed more severe outcomes. RSV hospitalisations continuously increase in both age groups, following a bi-annual pattern of severe and less severe seasons, which was not altered by the COVID-19 pandemic.

CONCLUSION

We demonstrate the relation between RSV waves in children and the elderly. NPI measures may protect the elderly from RSV infections and epidemiological data could be used to predict RSV waves early enough to prepare countermeasures.

Effects of infection control measures towards preventing SARS-CoV-2 outbreaks in a German choir boarding school from March 2020 to April 2022

Background

Singing in a choir was associated with larger outbreaks in the beginning of the SARS-CoV-2 pandemic.

Materials and methods

We report on the effect and acceptance of various infection control measures on the occurrence of SARS-CoV-2 infections in the world famous Domspatzen boys' choir from March 2020 to April 2022.

Results

In addition to basic general hygiene measures, systematic rRT-PCR testing and scientifically approved concepts of distancing during singing were applied. While single infections of choir members could not be avoided, singing-related outbreaks were not observed. Until the Omicron variant emerged, potential transmission of SARS-CoV-2 in the school was limited to only one case. Incidences at the school were never higher than in the comparable general population until then. While the impact of the pandemic on daily life and singing was rated as severe, especially by staff members, most students agreed with the usefulness of protection measures and rated them as acceptable. Students viewed regular testing as the most important tool to increase safety in the school.

Discussion

A bundle of infection control measures including regular testing can prevent outbreaks of SARS-CoV-2 even in the setting of choir singing. Measures are acceptable for choir members if they allow to continue with singing and performing.

Serum Neurofilament light chain (NfL) levels in children with and without neurologic diseases

BACKGROUND/OBJECTIVE

Serum neurofilament light chain (sNfL) is a specific biomarker of neuronal damage. Elevated sNfL levels have been reported in numerous neurologic diseases in adults, whereas data on sNfL in the pediatric population are incomplete. The aim of this study was to investigate sNfL levels in children with various acute and chronic neurologic disorders and describe the age dependence of sNfL from infancy to adolescence.

METHODS

The total study cohort of this prospective cross-sectional study consisted of 222 children aged from 0 to 17 years. Patients' clinical data were reviewed and patients were assigned to the following groups: 101 (45.5%) controls, 34 (15.3%) febrile controls, 23 (10.4%) acute neurologic conditions (meningitis, facial nerve palsy, traumatic brain injury, or shunt dysfunction in hydrocephalus), 37 (16.7%) febrile seizures, 6 (2.7%) epileptic seizures, 18 (8.1%) chronic neurologic conditions (autism, cerebral palsy, inborn mitochondrial disorder, intracranial hypertension, spina bifida, or chromosomal abnormalities), and 3 (1.4%) severe systemic disease. sNfL levels were measured using a sensitive single-molecule array assay.

RESULTS

There were no significant differences in sNfL levels between controls, febrile controls, febrile seizures, epileptic seizures, acute neurologic conditions, and chronic neurologic conditions. In children with severe systemic disorders, by far the highest NfL levels were found with an sNfL of 429 pg/ml in a patient with neuroblastoma, 126 pg/ml in a patient with cranial nerve palsy and pharyngeal Burkitt's lymphoma, and 42 pg/ml in a child with renal transplant rejection. The relationship between sNfL and age could be described by a second order polynomial with an R2 of 0.153 with a decrease of sNfL by 3.2% per year from birth to age 12 years and thereafter an increase by 2.7% per year until age 18 years.

CONCLUSIONS

In this study cohort, sNfL levels were not elevated in children with febrile or epileptic seizures, or various other neurologic diseases. Strikingly high sNfL levels were detected in children with oncologic disease or transplant rejection. A biphasic sNfL age-dependency was documented, with highest levels in infancy and late adolescence and the lowest levels in middle school age.

Analysis of COVID-19 Infection Chains in a School Setting: Data From a School-Based rRT-PCR-Gargle Pool Test System

BACKGROUND

School testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was implemented in some countries to monitor and prevent SARS-CoV-2 transmissions. Here, we analyze infection chains in primary schools and household members of infected students based on systematic real-time reverse-transcriptase polymerase-chain-reaction (rRT-PCR)-gargle pool testing.

METHODS

Students and school staff (N = 4300) of all 38 primary schools in the rural county of Cham, Germany, were tested twice per week with a gargle pool rRT-PCR system from April to July of 2021. Infection chains of all 8 positive cases identified by school testing were followed up.

RESULTS

In total, 8 positive cases were found by gargle pool PCR testing based on 96,764 school tests. While no transmissions occurred in the school setting, 20 of 27 household members of the 8 cases tested positive. The overall attack rate was 74.1% in families.

CONCLUSIONS

No school outbreaks occurred during the study period. All cases but 1 were initially picked up by school testing. No transmission from school to families was observed.

Differences in observed and self-reported compliance with the 5 moments for hand hygiene as a function of healthcare workers' empathy

BACKGROUND

Hand hygiene at critical time-points (as established by the WHO model 'Five moments for hand hygiene') remains the leading measure for minimising the risk of healthcare-associated infections. While many interventions have been tested to improve hand hygiene compliance (HHC) of healthcare workers (HCWs), little is known about the relation between HHC and HCW empathy.

AIM

The aim of this study was to investigate the relation between moment-specific HHC rates and HCWs' empathy, at both individual and ward levels.

METHODS

HHC data was collected via observation and self-report, staffs' empathy levels were measured using an established questionnaire. The survey was conducted on 38 wards of three tertiary-care hospitals in Germany. Observation data was obtained via in-house observations which were conducted up to eight months before or after the survey.

FINDINGS

Evidence for the expected correlation between HCW empathy and moment-specific HHC was found for both observed HHC (Moment 1: r = .483, p = .031; Moment 2: r = 588, p = .006) and self-reported HHC (Moment 1: r = .093, p = .092; Moment 2: r = .145, p = .008). In analyses of variance the critical interaction effect between empathy (i.e., lower vs. higher empathy) and designated time-point of hand hygiene (i.e., before vs. after reference task) was also significant.

CONCLUSION

HCWs' empathy should be considered as an important factor in explaining differences between moment-specific HHC rates. In consequence, empathy comes into focus not only as a crucial factor for high-quality patient care, but as an important contributor to improving HHC, too.

A strict mask policy for hospital staff effectively prevents from nosocomial influenza infections and mortality: monocentric data from five consecutive influenza seasons

BACKGROUND

Influenza infections acquired in hospital show increased mortality, especially in elderly patients with risk factors. Nevertheless, vaccination rates are low among both high-risk patients and healthcare workers (HCW). To more effectively prevent influenza infections in the hospital during the influenza season, we introduced a strict mouth-nose protection (MNP) requirement for all staff throughout the shift on the affected wards as an intervention and studied its effect on nosocomial infection rates.

METHODOLOGY

The present data were obtained in a retrospective, monocentric analysis over a period of four consecutive influenza seasons from 2015 - 2019. MNP for all staff during the whole shift as an intervention was introduced at 2017 and for the following seasons if at least three flu patients were in the ward at the same time. Data from hospitalised influenza patients before and after intervention were compared with regard to nosocomial incidences and mortality.

RESULTS

In the years with strict mandatory MNP (2017 - 2019), the nosocomial influenza incidence fell nearly 50 % (OR 0.40, 95%CI 0.28 - 0.56, p < 0.001) accompanied by a significant reduction in nosocomial mortality by 85% (OR 0.15, 95%CI 0.02 - 0.70, p = 0.007). The infectious pressure indicated by influenza incidences and patient days at risk were comparable before and after intervention, as was the low rate of vaccine uptake by nurses.

CONCLUSION

From our data, we conclude that mandatory MNP for HCW effectively protect patients from nosocomial influenza infections and mortality.

Performance evaluation of the Roche Elecsys Anti-SARS-CoV-2 S immunoassay

The Elecsys® Anti-SARS-CoV-2 S immunoassay (Roche Diagnostics International Ltd, Rotkreuz, Switzerland) has been developed for the detection of antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein. We evaluated the assay performance using samples from seven sites in Germany, Austria, and Switzerland. For specificity and sensitivity analyses, 7880 presumed negative pre-pandemic samples and 827 SARS-CoV-2 PCR-confirmed single or sequential samples from 272 different patients were tested, respectively. The overall specificity and sensitivity (≥14 days post-PCR) for the Elecsys Anti-SARS-CoV-2 S immunoassay were 99.95% (95% confidence interval [CI]: 99.87–99.99; 7876/7880) and 97.92% (95% CI: 95.21–99.32; 235/240), respectively. The Elecsys Anti-SARS-CoV-2 S immunoassay had significantly higher specificity compared with the LIAISON® SARS-CoV-2 S1/S2 IgG (99.95% [2032/2033] vs 98.82% [2009/2033]), ADVIA Centaur® SARS-CoV-2 Total (100% [928/928] vs 86.96% [807/928]), ARCHITECT SARS-CoV-2 IgG (99.97% [2931/2932] vs 99.69% [2923/2932]), iFlash-SARS-CoV-2 IgM (100.00% [928/928] vs 99.57% [924/928]), and EUROIMMUN Anti-SARS-CoV-2 IgG (100.00% [903/903] vs 97.45% [880/903]) and IgA (100.00% [895/895] vs 95.75% [857/895]) assays. The Elecsys Anti-SARS-CoV-2 S immunoassay had significantly higher sensitivity (≥14 days post-PCR) compared with the ARCHITECT SARS-CoV-2 IgG (98.70% [76/77] vs 87.01% [67/77]), iFlash-SARS-CoV-2 IgG (100.00% [76/76] vs 93.42% [71/76]) and IgM (100.00% [76/76] vs 35.53% [27/76]), and EUROIMMUN Anti-SARS-CoV-2 IgG (98.26% [113/115] vs 93.91% [108/115]) assays. Therefore, the Elecsys Anti-SARS-CoV-2 S assay demonstrated a reliable performance across various sample populations for the detection of anti-S antibodies.

Peripartal anti-SARS-CoV-2-IgA/IgG in asymptomatic pregnant women during regional SARS-CoV-2-outbreak

OBJECTIVES

The Severe Acute Respiratory Distress Corona Virus 2 (SARS-CoV-2) pandemic poses special challenges for the society and especially the medical staff. Even if a rather mild course is assumed among pregnant women the measures to prevent transmission of the infection are of outstanding importance.

METHODS

To screen asymptomatic pregnant women during admission to our university maternal hospital we focused on anti-SARS-CoV-2-specific IgG and IgA antibody responses. Hundred and fifty one women admitted to the hospital for childbirth or caesarean delivery were included. In case of suspicious anti-SARS-CoV-2-antibody levels an RT-PCR was performed to confirm an ongoing infection with SARS-CoV-2.

RESULTS

A total of 89% showed negative results for anti-SARS-CoV-2-IgA antibodies, whereas 3% were borderline and 7% positive (both labeled as suspicious). In only one patient with suspicious serology we detected SARS-CoV-2-RNA in the following RT-PCR. 2% presented anti-SARS-CoV-2-IgG antibodies, all being positive for anti-SARS-CoV-2-IgA. The observed positive rate of our study collective of 10.6% seemed much higher than the expected one (1.3%) based on the reports of the Robert Koch Institute and the specifications given by the test's manufacturer. The expected positive predictive value (PPV) was 4.3-6.7 times higher than the observed one.

CONCLUSIONS

To our knowledge this is the first report of anti-SARS-CoV-2-antibody levels in the peripartum period of asymptomatic women. As the positive anti-SARS-CoV-2 serology poorly correlated with the confirmatory RT-PCR and the fact that mainly the detection of the virus by PCR correlates with the patient's infectiousness we suggest to rather perform a SARS-CoV-2-PCR-based admission screening in perinatal centers to prevent the spread of the disease.

SARS-CoV-2 in pregnancy and possible transfer of immunity: assessment of peripartal maternal and neonatal antibody levels and a longitudinal follow-up

OBJECTIVES

In the current Severe Acute Respiratory Distress Coronavirus 2 (SARS-CoV-2) pandemic there is still great uncertainty about the effects of an infection in pregnancy especially regarding a possible fetal transmission of antibodies to SARS-CoV-2 and the longevity of this immunity.

METHODS

Sixteen women who were infected with SARS-CoV-2 during pregnancy and their offspring were included. The antibody response to SARS-CoV-2 was measured in mother and umbilical cord blood peripartum and in a follow-up examination 6-11 weeks after birth. Medical history, symptoms regarding SARS-CoV-2, obstetric and neonatal information were queried following recommendations by the WHO.

RESULTS

A total of 73% of the women and one third of the infants developed antibodies to SARS-CoV-2 spike (S) protein receptor binding domain (RBD), with a long interval between infection and birth proving favorable for a transplacentar transfer of antibodies to the neonates. All infants showed declining or vanishing antibody-titers in the follow-up examination, while the titers of their mothers were stable or even increased.

CONCLUSIONS

Our results demonstrate that transplacental transfer of SARS-CoV-2-specific antibodies is possible, but also indicate that the immunity that may be gained as a result might decrease in newborns postpartum. This provides important evidence that could be useful for further studies covering vaccination during pregnancy.

Results of WICOVIR Gargle Pool PCR Testing in German Schools Based on the First 100,000 Tests

Background: Opening schools and keeping children safe from SARS-CoV-2 infections at the same time is urgently needed to protect children from direct and indirect consequences of the COVID-19 pandemic. To achieve this goal, a safe, efficient, and cost-effective SARS-CoV-2 testing system for schools in addition to standard hygiene measures is necessary. Methods: We implemented the screening WICOVIR concept for schools in the southeast of Germany, which is based on gargling at home, pooling of samples in schools, and assessment of SARS-CoV-2 by pool rRT-PCR, performed decentralized in numerous participating laboratories. Depooling was performed if pools were positive, and results were transmitted with software specifically developed for the project within a day. Here, we report the results after the first 13 weeks in the project. Findings: We developed and implemented the proof-of-concept test system within a pilot phase of 7 weeks based on almost 17,000 participants. After 6 weeks in the main phase of the project, we performed >100,000 tests in total, analyzed in 7,896 pools, identifying 19 cases in >100 participating schools. On average, positive children showed an individual CT value of 31 when identified in the pools. Up to 30 samples were pooled (mean 13) in general, based on school classes and attached school staff. All three participating laboratories detected positive samples reliably with their previously established rRT-PCR standard protocols. When self-administered antigen tests were performed concomitantly in positive cases, only one of these eight tests was positive, and when antigen tests performed after positive pool rRT-PCR results were already known were included, 3 out of 11 truly positive tests were also identified by antigen testing. After 3 weeks of repetitive WICOVIR testing twice weekly, the detection rate of positive children in that cohort decreased significantly from 0.042 to 0.012 (p = 0.008). Interpretation: Repeated gargle pool rRT-PCR testing can be implemented quickly in schools. It is an effective, valid, and well-received test system for schools, superior to antigen tests in sensitivity, acceptance, and costs.

Symptoms, SARS-CoV-2 Antibodies, and Neutralization Capacity in a Cross Sectional-Population of German Children

Background: Children and youth are affected rather mildly in the acute phase of COVID-19 and thus, SARS-CoV-2 infection infection may easily be overlooked. In the light of current discussions on the vaccinations of children it seems necessary to better identify children who are immune against SARS-CoV-2 due to a previous infection and to better understand COVID-19 related immune reactions in children. Methods: In a cross-sectional design, children aged 1-17 were recruited through primary care pediatricians for the study (a) randomly, if they had an appointment for a regular health check-up or (b) if parents and children volunteered and actively wanted to participate in the study. Symptoms were recorded and two antibody tests were performed in parallel directed against S (in house test) and N (Roche Elecsys) viral proteins. In children with antibody response in either test, neutralization activity was determined. Results: We identified antibodies against SARS-CoV-2 in 162 of 2,832 eligible children (5.7%) between end of May and end of July 2020 in three, in part strongly affected regions of Bavaria in the first wave of the pandemic. Approximately 60% of antibody positive children (n = 97) showed high levels (>97th percentile) of antibodies against N-protein, and for the S-protein, similar results were found. Sufficient neutralizing activity was detected for only 135 antibody positive children (86%), irrespective of age and sex. Initial COVID-19 symptoms were unspecific in children except for the loss of smell and taste and unrelated to antibody responses or neutralization capacity. Approximately 30% of PCR positive children did not show seroconversion in our small subsample in which PCR tests were performed. Conclusions: Symptoms of SARS-CoV-2 infections are unspecific in children and antibody responses show a dichotomous structure with strong responses in many and no detectable antibodies in PCR positive children and missing neutralization activity in a relevant proportion of the young population.

An epidemic CC1-MRSA-IV clone yields false-negative test results in molecular MRSA identification assays: a note of caution, Austria, Germany, Ireland, 2020

We investigated why a clinical meticillin-resistant Staphylococcus aureus (MRSA) isolate yielded false-negative results with some commercial PCR tests for MRSA detection. We found that an epidemic European CC1-MRSA-IV clone generally exhibits this behaviour. The failure of the assays was attributable to a large insertion in the orfX/SCCmec integration site. To ensure the reliability of molecular MRSA tests, it is vital to monitor emergence of new SCCmec types and junction sites.

Symptoms and immunoglobulin development in hospital staff exposed to a SARS-CoV-2 outbreak

BACKGROUND

Worldwide, the number of SARS-CoV-2 infections is increasing. Serological immunoglobulin tests may help to better understand the development of immune mechanisms against SARS-CoV-2 in COVID-19 cases and exposed but asymptomatic individuals. The aim of this study was to investigate exposure to SARS-CoV-2, symptoms, and antibody responses in a large sample of healthcare workers following a COVID-19 outbreak.

METHODS

A COVID-19 outbreak among staff members of a major German children's and women's hospital was followed by massive RT-PCR SARS-CoV-2 tests and provided the opportunity to study symptoms, chains of infection, and SARS-CoV-2-specific antibody responses (IgG and IgA) by ELISA. Study participants were classified as COVID-19 cases, and persons with close, moderate, or no exposure to SARS-CoV-2 in the clinical setting, respectively.

RESULTS

Out of 201 study participants, 31 were COVID-19 cases. While most study participants experienced many symptoms indicative for SARS-CoV-2 infection, anosmia and coughing were remarkably more frequent in COVID-19 cases. Approximately 80% of COVID-19 cases developed some specific antibody response (IgA and IgG) approximately 3 weeks after onset of symptoms. Subjects in the non-COVID-19 groups had also elevated IgG (1.8%) and IgA values (7.6%) irrespective of contact history with cases.

CONCLUSION

We found that a significant number of diseased did not develop relevant antibody responses three weeks after symptom onset. Our data also suggest that exposure to COVID-19 positive co-workers in a hospital setting is not leading to the development of measurable immune responses in a significant proportion of asymptomatic contact persons.

Clinimetric properties and suitability of selected quality indicators for assessing antibiotic use in hospitalized adults: a multicentre point prevalence study in 24 hospitals in Germany

OBJECTIVES

The capability to measure and monitor the quality of antibiotic prescribing is an important component of antibiotic stewardship (ABS) programmes. Several catalogues of consensus-based structure and process-of-care quality indicators (QIs) have been proposed, but only a few studies have tested and validated ABS QIs in practice tests. This multicentre study determined the clinimetric properties and suitability of a set of 33 process QIs for ABS that had earlier been developed and in part recommended in a German-Austrian hospital ABS practice guideline.

METHODS

Two point prevalence surveys were conducted in a convenience sample of 24 acute care hospitals throughout Germany, and data of all screened adult inpatients with prescription of a systemic antibiotic at a given day (n=4310) were included in the study. For each QI, the following clinimetric properties were assessed: applicability, feasibility, performance, case mix stability and interobserver reliability.

RESULTS

Eighteen QIs were considered sufficiently feasible, applicable and reliable, and had adequate room for improvement. The finally selected QIs primarily cover antibiotic therapy of common infections (bloodstream infection, pneumonia and urinary tract infection), while two of the QIs each address surgical prophylaxis and general aspects of antibiotic administration.

CONCLUSIONS

Practice tests may be important to test the suitability of consensus process-of-care QIs in the field of hospital ABS. The 18 selected QIs considered suitable enough for hospital ABS in this study should be regarded as priority QIs useful for internal quality control and assurance. More research and additional practice tests may be needed to confirm their suitability for external quality assessment schemes.

Immune response to SARS-CoV-2 in health care workers following a COVID-19 outbreak: A prospective longitudinal study

OBJECTIVE

Currently, little is known about the progression of an immune response against SARSCoV- 2 upon infection or sub-infection-exposure over time. We examined the serologic response in healthcare workers up to 12 weeks after a well-documented and contained outbreak and compared results with findings from earlier serologic testing in the same population.

METHODS

This study followed 166 health care workers of the University Perinatal Care Center, Regensburg, Germany, for up to 12 weeks. 27 of the subjects had previously tested positive for the presence of SARS-CoV-2 by PCR testing and developed COVID-19. Serologic responses were tested with two independent commercially available test kits.

RESULTS

77.8 % of COVID-19 study subjects developed a specific IgG-response over the course of the 12-week study, while none of the COVID-19 contact groups had a detectable IgG response. Amongst most COVID-19 patients the values of detectable IgG-responses significantly increased over time as confirmed with both tests, while that of positive IgA responses decreased. Between the number of reported symptoms and antibody responses in COVID-19 patients no correlation was found and no new cases of seroconversion were identified in asymptomatic coworkers with negative PCR during the outbreak.

CONCLUSIONS

Immune response after COVID-19 increases significantly over time but still approximately 22 % of COVID-19 patients did not mount a measurable serologic immune response within 60 days. Exposed co-workers did not develop any relevant antibody levels at all. We conclude that immunity after infection increases over time, but the antibody response does not develop reliably in all infected people.

SARS-CoV-2 antibody testing-questions to be asked

Severe acute respiratory syndrome coronavirus 2 infection and development of coronavirus disease 2019 presents a major health care challenge of global dimensions. Laboratory diagnostics of infected patients, and the assessment of immunity against severe acute respiratory syndrome coronavirus 2, presents a major cornerstone in handling the pandemic. Currently, there is an increase in demand for antibody testing and a large number of tests are already marketed or are in the late stage of development. However, the interpretation of test results depends on many variables and factors, including sensitivity, specificity, potential cross-reactivity and cross-protectivity, the diagnostic value of antibodies of different isotypes, and the use of antibody testing in identification of acutely ill patients or in epidemiological settings. In this article, the recently established COVID-19 Task Force of the German Society for Clinical Chemistry and Laboratory Medicine (DGKL) addresses these issues on the basis of currently available data sets in this rapidly moving field.

Successful containment of Covid-19 outbreak in a large maternity and perinatal center while continuing clinical service

With increasing number of SARS-CoV-2 infections and COVID-19 patients to be taken care of by the health system, more and more health workers become affected by the disease. It has been reported that right from the beginning of the outbreak in Lombardy up to 20% of the doctors and nurses became infected. Under these circumstances, the regular operation of health institutions already suffering from a shortage of staff becomes difficult. This has led to complete or partial shutdowns of hospitals, either due to a lack of uninfected personnel or because of uncontrollable chains of infection endangering patients. In one of the largest university perinatal center in Bavaria with more than 3000 births per year, an outbreak of COVID-19 occurred in March 2020, affecting 36 staff members, including doctors, nurses, and midwives. Here, we describe the outbreak and present the measures contributing to the successful containment of the outbreak within three weeks. At the same time, clinical services could be maintained, however, not without deployment of personnel exposed to employees infected with SARS-CoV-2. Apart from massive testing of personnel in pre-defined phases and increased hygiene measures, including a general obligation to wear surgical face masks, we identified the need to monitor cases of illness across all groups of employees, to ensure social distancing within personnel and to evaluate contacts of clinical personnel outside of the hospital environment, in order to be able to interpret chains of infections and to disrupt them. Overall, only a bundle of measures is needed to contain such an outbreak.

Validation of adapted daily dose definitions for hospital antibacterial drug use evaluation: a multicentre study

Background

The WHO/ATC (Anatomical Therapeutic Chemical) index DDD (WHO-DDD) is commonly used for drug consumption measurement. Discrepancies between WHO-DDD and actual prescribed daily doses (PDD) in hospitals have prompted alternative dose definitions adapted to doses recommended in hospital practice guidelines [recommended daily doses (RDD)].

Methods

In order to validate RDD we performed modified point prevalence surveys in 24 acute care hospitals and recorded 20620 PDD of antibiotics given to 4226 adult patients on the day of the survey and the 6 preceding days. We calculated RDD and WHO-DDD and compared them with PDD.

Results

The rate of RDD corresponding to PDD was higher than the corresponding rate for WHO-DDD (pooled data, 55% versus 30%) and the differences were similar across the hospital sample, but varied according to drug/drug class, route of administration, indication and renal function. RDD underestimated actual consumption by 14% overall, while WHO-DDD overestimated total antibacterial consumption by 28% (pooled data; median values RDD -10% versus WHO-DDD +32%). The deviations of estimated from actual drug use volumes were largest for β-lactams (RDD -11% versus WHO-DDD +49%), in particular for penicillins (-11% versus +64%), if WHO-DDD were used.

Conclusions

Hospital antibiotic consumption surveillance systems using current WHO-DDD should address the uneven discrepancies between actual prescribing and consumption estimates according to drug class that may lead to misclassification in benchmark analyses. We recommend using validated RDD as a supplementary measure to the WHO-DDD for detailed analyses.

[Clinical Characteristics and Course of Infections by Influenza A- and Respiratory Syncytial Virus (RSV) in Hospitalized Adults]

There is little evidence on the clinical characteristics and the course of complicated infections with respiratory syncytial virus (RSV) compared to influenza A in adults. Therefore, the present monocenter study aims to compare infections with RSV and influenza A with regard to potential predisposing factors, clinical profile, course and outcome in hospitalized patient.

MATERIAL AND METHODS

 the study was performed between Jan 1th and March 31 this year and included all hospitalized patients with a Polymerase chain-reaction-(PCR) confirmed infection of influenza A and RSV. Patients were characterized by clinical symptoms at the time of diagnosis, laboratory parameters of inflammation and potential predisposing factors like chronical diseases of heart, lung, kidney, metabolism and tumors. Data on the length of hospital stay, origin of infection (nosocomial), rate of pneumonia, antimicrobial use, need of mechanical ventilation and hospital mortality were obtained to evaluate clinical severity and outcome.

RESULTS

 A total of 190 patients with Influenza A and 98 patients with RSV were included. Both patient groups did not differ with regard to anthropometric data and clinical symptoms: it was surprising to see that only 2/3 oft all patients exert symptoms of a respiratory infection. 15.3 % of influenza A and 13.3 % RSV infections were defined as being nosocomial. Comparing the clinical course and outcome, patients with RSV infections and chronical disease of the lung had an increased rate of mechanical ventilations (odds ratio 10.55 [95 % CI 1.18 - 507.1] p = 0.014).

CONCLUSIONS

 The present data clearly show that RSV is a frequent pathogen in hospitalized adults with complicated infections in the winter season. RSV infections seems to be more severe compared to influenza A particular in patients with chronic lung disease, but were as frequent as influenza A of nosocomial origin. In this context, an early diagnosis seems to be helpful for a successful infections prevention management under hospital conditions.

[Rational antibiotic treatment of mediastinitis]

Mediastinitis occurs as a severe complication of thoracic and cardiac surgical interventions and is the result of traumatic esophageal perforation, conducted infections or as a result of lymphogenic and hematogenic spread of specific infective pathogens. Treatment must as a rule be accompanied by antibiotics, whereby knowledge of the spectrum of pathogens depending on the pathogenesis is indispensable for successful antibiotic therapy. Polymicrobial infections with a high proportion of anaerobes are found in conducted infections of the mediastinum and after esophageal perforation. After cardiac surgery Staphylococci are the dominant pathogens and a nasal colonization with Staphylococcus aureus seems to be a predisposing risk factor. Fungi are the predominant pathogens in immunocompromised patients with consumptive underlying illnesses and can cause acute or chronic forms with granulomatous inflammation. Resistant pathogens are increasingly being found in high-risk patient cohorts, which must be considered for a calculated therapy. For calculated antibiotic therapy the administration of broad spectrum antibiotics, mostly beta-lactams alone or combined with metronidazole is the therapy of choice for both Gram-positive and Gram-negative bacteria inclusive of anaerobes. For patients at risk, additional antibiotic classes with a spectrum against methicillin-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococcus (VRE) can be administered. Increasing rates of multidrug-resistant Gram-negative bacteria (e.g. Enterobacteriaceae) and non-fermenting bacteria (e.g. Pseudomonas and Acinetobacter) in individual cases necessitates the use of polymyxins (e.g. colistin), new tetracyclines (e.g. glycylglycines) and newly developed combinations of beta-lactams and beta-lactam inhibitors. For treatment of fungal infections (e.g. Candida, Aspergillus and Histoplasma) established and novel azoles, amphotericin B and echinocandins seem to be successful; however, detection of Candida, particularly in mixed infections does not always necessitate treatment. Mediastinitis is still a severe infectious disease with a high mortality, which necessitates an early and broad spectrum antibiotic therapy; however, with respect to optimal duration of therapy and selection of antibiotics, data from good quality comparative studies are lacking.

Effect of Daptomycin on Local Interleukin-6, Matrix Metalloproteinase-9, and Metallopeptidase Inhibitor 1 in Patients With MRSA-Infected Diabetic Foot

Infection is a major cause of the diabetic foot syndrome that is promoted by the increased burden of multiresistant germs like methicillin-resistant Staphylococcus aureus (MRSA). Maximizing positive outcome for serious MRSA infections requires an aggressive treatment approach and careful monitoring of the healing process. Therefore, we examined 8 patients with MRSA-infected diabetic foot syndrome of Wagner classification grade 2 or 3 (corresponding to the Texas classification stage 2 or 3) during antibiotic treatment with daptomycin. We documented the wound size and obtained samples of wound secretion for analyses of proinflammatory interleukin-6 (IL-6), protease (matrix metalloproteinase-9 [MMP-9]), and antiprotease (metallopeptidase inhibitor 1 [TIMP-1]) activity. During the course of anti-MRSA therapy, we observed a decrease in the concentration of local IL-6 within the first 3 days followed by a decrease of MMP-9 and an increase of TIMP-1. Finally, a reduction of wound size was documented. The present data show that efficient antimicrobial treatment with daptomycin has a number of beneficial effects on wound healing at the molecular level in MRSA-infected diabetic foot ulcers.

Effect of daptomycin on local interleukin-6, matrix metalloproteinase-9, and metallopeptidase inhibitor 1 in patients with MRSA-infected diabetic foot

Infection is a major cause of the diabetic foot syndrome being aggravating by the increased burden of multiresistant germs like methicillin-resistant Staphylococcus aureus (MRSA). Maximizing positive outcome for serious MRSA infections requires an aggressive treatment approach and a careful monitoring of the healing process. Therefore, we examined 8 patients with MRSA-infected diabetic foot syndrome Wagner classification grades 2 or 3 (corresponding to the Texas classification stage 2 and 3) during antibiotic treatment with daptomycin. We documented the wound size and obtained samples of wound secretion for analyses of pro-inflammatory interleukin-6 (IL-6), protease (matrix metalloproteinase-9 [MMP-9]), and antiprotease activity (metallopeptidase inhibitor 1 [TIMP-1]). During the course of anti-MRSA therapy, a decrease in the concentration of local IL-6 within the first 3 days followed by a drop of MMP-9 and an increase of TIMP-1 was observed. Finally, a reduction of wound size could be documented. The present data show that efficient antimicrobial treatment with daptomycin leads to a number of beneficial processes at the molecular level of wound healing in MRSA-infected diabetic foot ulcers.

Diabetic foot infections: microbiological aspects, current and future antibiotic therapy focusing on methicillin-resistant Staphylococcus aureus

Diabetic patients are at increased risk of complicated skin, skin structure and bone infections including infections of diabetic foot ulcerations (DFU). Analyses of epidemiology and microbial pathogenicity show that staphylococci seem to be predestined to induce such infections. In addition, multidrug resistance particularly due to an increasing prevalence of methicillin-resistant Staphylococcus aureus (MRSA) seems to be the challenge for effective antibiotic therapy. With regard to infections with MRSA, classical agents like vancomycin, linezolid, fosfomycin or trimethroprim-sulphametoxazol might be agents of choice in DFU. New-generation drugs including broad-spectrum tetracyclines like tigecycline, first and second generation of cyclic lipopeptides, anti-MRSA β-lactams including ceftobiprole and anti-MRSA antibodies are developed or in progress and the hope for the future.

Evaluation of a rapid culture-based screening test for detection of methicillin resistant Staphylococcus aureus

The performance of a culture based assay, BacLite Rapid MRSA for the rapid detection (5 hours) of methicillin resistant Staphylococcus aureus (MRSA) from specimens (n = 377) obtained from nares, throat, wounds and perineum was investigated. Compared to culture based reference methods (chromogenic MRSA ID (bioMerieux)), selective enrichment broth, PBP2' latex agglutination (Oxoid) and VITEK 2 identification (bioMerieux), an overall sensitivity of 71% with a 82% specificity and a negative predictive value (NPV) of 95% was provided. The Baclite test is rapid and easy to use and has the advantage of a culture-based detection method for MRSA.

Mean cell volume of neutrophils and monocytes compared with C-reactive protein, interleukin-6 and white blood cell count for prediction of sepsis and nonsystemic bacterial infections

Clinicians are in need of better diagnostic markers for rapid diagnosis of severe infections. Therefore, we studied the diagnostic significance of mean cell volume of neutrophils (MNV) and monocytes (MMV) compared with Interleukin-6 (IL-6), C-reactive protein (CRP) and white blood cell count for predicting systemic clinical infection (sepsis). MNV and MMV were obtained by volume conductivity scatter (VCS) technique of the Coulter LH 750 hematology analyzer during automated differential counts, and blood samples from patients with sepsis (n = 37), nonsystemic bacterial infections (n = 39) and controls (n = 48) were studied. We observed a significant increase in MNV and MMV in the sepsis group compared with limited infections and controls. However, at a designated cut-off point of 250 pg/ml, IL-6 seemed to be the best predictor for sepsis with a sensitivity of 93% and a specificity of 76%. Compared with CRP (cut-off point 60 mg/dl), MNV at a cut-off of 150 had a comparable sensitivity and specificity and was the most predictive VCS parameter. Taken together, MNV and MMV seemed to be potential parameters to discriminate between sepsis and nonsystemic infections.

Determination of anti GAD65 autoantibodies with an ELISA before and after standardization with the new international reference serum

The serum of a stiff-man syndrome patient was declared international GAD reference standard at the "1st GAD Antibody Workshop" held at the "12th International Immunology and Diabetes Workshop" in Orlando, Florida, USA 1993. A comparative study was performed with 123 diabetic and non-diabetic patients to evaluate whether standardization of this reference serum had changed the properties of a commercially available ELISA assay. All samples classified positive with the old test were confirmed with the new assay. Four additional samples with high "normal" values became positive with the new test. One of them was a control person having a family history of diabetes and genetic loci DR4/DR11. These findings might implicate a higher risk for the development of IDDM. The new standardization and adaptation of the ELISA seems to have influenced the sensitivity of the test positively.

Interleukin-6 concentrations in wound fluids rather than serological markers are useful in assessing bacterial triggers of ulcer inflammation

Bacterial pathogenicity, microbial load and diversity are decisive for outcome and therapy of non healing ulcers. However, until now, no routine laboratory parameter is available to assess the inflammatory level caused by chronic wound infections. We thus investigated the usefulness of levels of interleukin (IL)-6 and tumour necrosis factor alpha (TNFalpha) in wound fluids for assessing ulcer inflammation in the presence or absence of microbial triggers. In addition, the predictive values of local cytokine analyses were compared with those of C-reactive protein (CRP) and lipopolysaccharide-binding protein (LBP) because serological markers are normally used to underline the suspicion of wound infections. The present data from chronic arterial and venous ulcers (n = 45) clearly show that mixed bacterial infections increased IL-6 and TNFalpha concentrations in wound fluids when compared with ulcers with a monomicrobial infection (P < 0.01 and P < 0.05, respectively). IL-6 was also significantly elevated when a high bacterial load [versus <10(5) colony-forming units (cfu)/ml: P = 0.04] or an infection with Pseudomonas was observed (versus isolation of non Pseudomonas strains: P = 0.05). Although distinct proinflammatory triggers may interfere with regard to cytokine levels, sensitivity and specificity were significant in predicting bacterial risk factors, particularly for IL-6 at a designated cut-off of 125 pg/ml (sensitivity and specificity for predicting a mixed infection: 70% and 64%, for predicting a bacterial load of >10(5) cfu/ml: 62% and 57% and for predicting an infection with Pseudomonas: 90% and 57%). In contrast to local cytokine levels, the serological markers CRP and LBP were not associated with the presence of any of the investigated bacterial triggers. Focusing on the aim of the study, IL-6 analysed in wound washouts seems to be a useful diagnostic marker for a sensitive and specific assessment of ulcers inflammation with regard to bacterial triggers.

Differential effects of PDGF-BB on matrix metalloproteases and cytokine release in fibroblasts of Type 2 diabetic patients and normal controls in vitro

AIMS/HYPOTHESIS

The complex process of wound healing is regulated by various growth factors. The systemic character of diabetes mellitus favors the chronification of diabetic wounds. In this study, the in vitro effects of platelet-derived growth factor (PDGF)-BB on the expression of cytokines and matrix metalloproteases (MMPs) in fibroblasts of Type 2 diabetic patients and healthy controls were investigated.

METHODS

We studied six Type 2 diabetic patients (mean Hba1(c)=7.5%) and six healthy controls. For proliferation studies, cultivated fibroblasts, prepared from biopsies taken from the thigh, were stimulated with different concentrations of PDGF. After 48 h, the expression of MMPs and cytokines was measured. We analysed the mRNA expression by RT-PCR (TaqMan), tissue protein levels by zymography, and cell supernatant levels by ELISA.

RESULTS

Levels of MMP-mRNA were elevated in diabetic fibroblasts compared with healthy controls. At baseline, MMP-2 protein levels were significantly increased in the fibroblast of diabetic patients (P=.019). For MMP-9, a trend towards higher levels (P=.3) was found. After incubation with PDGF, a significant reduction of MMP-9 (P=.01) and MMP-13 (P=.04) was found. Analysis of cytokine release in cell culture supernatant showed elevated levels of interleukin (IL)-8 at baseline conditions. MMP-1 and MMP-2 levels in the supernatant were concentration-dependently reduced.

CONCLUSIONS

This study, for the first time, demonstrates elevated MMPs in cultivated fibroblasts (derived from intact skin and not from an open wound) of diabetic patients compared with healthy controls under in vitro conditions. Therefore, our data support the hypothesis of alterations of wound healing in diabetic patients on the cellular level, reflecting the systemic character of the disease.

Antibiotic therapy for diabetic foot infections: comparison of cephalosporines with chinolones

Diabetic foot complications are the most common cause of non-traumatic lower extremity amputations and uncontrolled infections represent a major risk factor. This open prospective, multicenter trial compared the efficacy of two antibiotic regimens for treatment of foot infections Wagner stage II or III in diabetic adults. Three hundred diabetic patients with severe, limb-threatening foot infection were consecutively enrolled in a prospective, observational, matched pairs controlled study to test two different antibiotic regimes (ceftriaxone vs chinolones) in addition to standard treatment of foot infection. After matching, 90 patients--each receiving ceftriaxone or chinolones--were analyzed. Our study demonstrated that treatment with a third generation cephalosporine is as effective as a treatment with chinolones. Response (reaching Wagner I or 0) was achieved in 58.0% in the ceftriaxone group and in 51.1% in the chinolone group (NS.). Fourteen days after initiation of treatment, the number of patients with microbiological isolates decreased in both groups (52 to 5 in the ceftriaxone group and 60 to 12 in the chinolone group). At hospital discharge, 66.0% of ceftriaxone and 64.4 of chinolone-treated diabetic ulcers were cured or improved. In summary, both substances proved to be effective in the primary antibiotic treatment of the diabetic foot; an early broad spectrum antibiotic treatment, that covers both gram-positive and gram negative bacteria as well as anerobes is undisputedly an imperative therapeutic intervention for the treatment of diabetic foot infection.

[Microbiological aspects and antibiotic therapy of diabetic foot infections]

IMMUNOLOGICAL AND MICROBIOLOGICAL ASPECTS OF DIABETIC FOOT INFECTIONS: Diabetic patients are at increased risk of severe skin and bone infections. Immunological disturbances are reasonable and due to altered specific and unspecific cellular immune responses. Analysis of epidemiology and microbial pathogenicity shows that staphylococci seem to be predestined to induce such infections. Staphylococcus aureus and coagulase-negative staphylococci are able to adhere to the wound ground by a sequela of mechanisms. Initial bacterial adherence is due to hydrophobicity, ion exchanges, and specific binding of bacterial adhesion molecules to cellular receptors. Moreover, staphylococci secrete polysaccharides which form a biofilm together with multilayer cell clusters. The highly structured communities within a biofilm are resistant to distinct immunoeffectors and have a decreased susceptibility to antibiotics in vivo.

ASPECTS OF ANTIBIOTIC THERAPY

Assessing the severity of an infection is essential to selecting an antibiotic regimen, the mode of drug administration, and the duration of therapy. Regimens for severe and chronic infections are broader spectrum and often intravenously to obtain high drug concentrations immediately. Infections of the bone often require an antibiotic therapy for > 4 weeks, while a 1- to 2-week therapy for mild to moderate infections has been found to be effective.

CONCLUSIONS

Because of the tremendous progress in diagnostics and therapy of diabetic foot infections, infectious complications can be successfully treated by appropriate wound care, metabolic control, and early surgical and antibiotic intervention. Bacterial biofilms involved into chronic infections are new aspects currently not visualized by clinical therapy. Besides the classic antimicrobial therapy, new concepts of an enzymatic therapy or the inhibition of bacterial "communication" (quorum sensing) are in progress and the hope for the future.

Contrasting effects of long-term treatment with IFN-gamma in endothelial cells: increase in IL-6 secretion versus decrease in IL-8 secretion, NF-kappa B, and AP-1 activation

The benefit of neutrophil exclusion from type 1 T helper cell (TH1) inflammatory processes was demonstrated in clinical studies. Increased recruitment of lymphocytes and monocytes to endothelium and impaired recruitment of polymorphonuclear neutrophils (PMNs) following interferon-gamma (IFN-gamma) treatment were described. The present study demonstrates that a 24 h treatment with IFN-gamma increases interleukin (IL)-6 release but reduces IL-8 secretion of both untreated and of tumor necrosis factor-alpha (TNF-alpha)-stimulated endothelial cells (ECs), favoring the attraction of lymphocytes but not of neutrophils. Alteration of cytokine release was accompanied by reduced basal and TNF-alpha-stimulated nuclear factor-kappa B (NF-kappa B) and activator protein-1 (AP-1) activity. However, IFN-gamma application neither altered gene expression of both TNF-alpha receptors (p55 and p75) nor cellular density of TNF-alpha receptor-2 (p75). Therefore, immune-modulatory action of IFN-gamma seems to be mediated by signal transduction molecules.

Expression of matrix-metalloproteinases and their inhibitors in the wounds of diabetic and non-diabetic patients

AIMS/HYPOTHESIS

The molecular factors that cause an acute wound in diabetic patients to become chronic have not yet been established. Wound healing is known to require a balance between the accumulation of collagenous and non-collagenous extracellular matrix components and their remodelling by matrix metalloproteinases (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs). Our aim was to assess if the concentrations of MMPs and TIMPs were different between acute and chronic wounds in diabetic patients by analysing biopsy samples.

METHODS

A 5 mm punch biopsy was taken from 20 diabetic foot ulcers of patients before initiating treatment and from traumatic wounds of 12 non-diabetic patients 2 days after injury. The concentrations of MMP-1, MMP-2(pro), MMP-2(active), MMP-8, MMP-9 and TIMP-2 were measured in detergent extracts of the biopsy homogenates using ELISAs and gelatin-zymography.

RESULTS

The concentration of MMP-1 was increased 65-fold in biopsies of diabetic foot ulcers compared with the concentrations measured in biopsies of traumatic wounds. Similarly, MMP-2(pro) were increased threefold, sixfold for MMP-2(active), twofold for MMP-8 and 14-fold for MMP-9 compared to average concentrations in biopsies of traumatic wounds. Furthermore, the expression of TIMP-2 was reduced twofold in diabetic wounds compared with lesions of non-diabetic patients.

CONCLUSION/INTERPRETATION

The combination of increased concentrations of MMPs with decreased concentrations of TIMP-2 in chronic diabetic foot ulcers compared with healing wounds in normal patients suggests that the increased proteolytic environment contributes to the failure of diabetic wounds to heal. New treatment strategies for healing chronic diabetic foot ulcers could be directed towards reducing concentrations of MMPs and increasing levels of TIMPs.

Small-sized low-density lipoproteins of subclass B from patients with end-stage renal disease effectively augment tumor necrosis factor-alpha-induced adhesive properties in human endothelial cells

Increased prevalence of small-sized low-density lipoprotein (LDL) subclass B (diameter < 25.5 nm) possibly is involved in the multifactorial process of cardiovascular disease in patients with end-stage renal disease. Given these epidemiological observations, mechanisms underlying the combined effect of a proinflammatory insult and LDL of different subclasses (subclass A, diameter > 25.5 nm, and subclass B) in a cellular model were investigated. For this, human umbilical vein endothelial cells were preexposed to LDL, then stimulated with tumor necrosis factor-alpha (TNF-alpha). Modulatory effects of LDL phenotypes on the activation of adhesion molecules, monocyte adherence, and transcriptional activity of nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) were investigated. Our data show that subclass B LDLs were metabolized through nonspecific scavenger receptors and specific LDL-receptor pathways in endothelial cells. Furthermore, LDL subclass B in comparison to subclass A more effectively enhanced monocyte recruitment and adhesive properties of endothelial cells in response to TNF-alpha. These effects appeared not to be mediated by oxidative stress-responsive NF-kappaB because modulation of this transcription factor by LDL was moderate and similar for both LDL phenotypes. Conversely, effects of LDL subclass B were considered to be caused by augmented AP-1 binding activity. In conclusion, the present model provides new clues in atherogenic mechanisms of small-sized LDLs, which sensitize vascular cells to inflammatory signals more effectively than normal-sized LDLs.

Blastocystis hominis modulates immune responses and cytokine release in colonic epithelial cells

An experimental in vitro model has been developed in order to determine whether Blastocystis hominis is able to trigger inflammatory cytokine response in colonic epithelial cells. After 24 h incubation of B. hominis with the cell lines HT-29 and T-84, B. hominis cells were not able to cause cytopathic effects, but significant increases in the release of the cytokines IL-8 and GM-CSF could be observed. However, after the first 6 h of co-incubation, the production of IL-8 was not increased in HT-29 cells, and even reduced when Escherichia coli (bacteria or lipopolysaccharide) was present during co-incubation. Similar effects were observed using supernatants of B. hominis culture. These data indicate that B. hominis induces as well as modulates the immune response in intestinal epithelial cells, and we conclude that different pathophysiological events may occur during B. hominis infection.

Regulation of mu-opioid receptor gene transcription by interleukin-4 and influence of an allelic variation within a STAT6 transcription factor binding site

Morphine and the endogenous opioid peptide beta-endorphin exert neuromodulatory as well as immunomodulatory effects, which are transduced by mu-opioid receptors. In this report we show that stimulation with interleukin-4 induces mu-opioid receptor transcripts in human primary blood cells (T cells and polymorphonuclear leukocytes), immune cell lines (Raji, U-937, and HMEC-1), and dendritic cells. In nonstimulated immune cells this gene is silent. In addition, mu receptor transcription is up-regulated by interleukin-4 in cultures of primary rat neurons. Transient transfection experiments in Raji and SH SY5Y neuronal cells with human and rat reporter gene constructs linked the interleukin-4 effect directly to cis-active mu receptor promoter elements located at nucleotide -997 on the human gene and nucleotide -727 on the rat gene. The interleukin-4 response elements function orientation independently. They bind STAT6 transcription factors as shown by electrophoretic mobility shift assays. In the human gene, a single nucleotide polymorphism within the interleukin-4 response element reduces the trans-activating potential of this element by 50%, which may affect the phenotype of persons carrying this variation. These findings provide a molecular basis for understanding bidirectional interactions between the opioid system and the immune system.

Factors explaining the difference of total homocysteine between men and women in the European Investigation Into Cancer and Nutrition Potsdam study

Interestingly, plasma total homocysteine (tHcy) concentration is consistently higher in men than in women. This observation deserves further investigations because elevated tHcy concentrations have been shown to be independently associated with coronary, peripheral, and cerebral vascular diseases. It was the aim of the present study to define major determinants of plasma tHcy in a healthy middle-aged German population under particular consideration of the gender factor. The study population was obtained from an ongoing recruitment procedure for a cohort study and comprised 336 men and women, aged 40 to 65 years. Exclusion criteria were elevated creatinine levels in blood, history of skin or atherosclerotic diseases, current use of vitamins or other supplements, and heavy smoking. Plasma tHcy, folate, vitamin B12, vitamin B6, creatinine, testosterone and estradiol, protein, and hematocrit were measured. Fat-free mass was assessed by skinfold thickness. The C677T polymorphism of the methylenetetrahydrofolate reductase (MTHFR), a key enzyme of folate and homocysteine metabolism, was determined by polymerase chain reaction (PCR) with restriction enzyme analysis. In this population, plasma tHcy ranged from 5 to 46 micromol/L. The frequency of the T allele of the MTHFR was 0.29, which is lower than in other populations. A total of 54.2% of this population was homozygote for the wild-type, 39.6% heterozygote, and 6.2% homozygote for the mutation. tHcy correlated negatively with folate and cobalamin concentration in blood and positively with creatinine. No correlation was seen with vitamin B6. From the gender-related variables, tHyc correlated significantly with fat-free mass and testosterone and inversely with estradiol. The difference between gender with regard to tHcy was mainly explained by differences in fat-free mass, but also by estradiol concentrations. The following contributions to the variation of tHcy were seen in a multivariate regression model: plasma cobalamin (11%), creatinine (11%), plasma folate (8%), fat-free mass (5%), estradiol (2%), MTHFR polymorphisms (2%), and plasma protein (1%). We concluded that tHcy in the general population has a variety of determinants ranging from nutrition, internal metabolic parameters to gender-related variables.

Relation between homocysteinaemia and diabetic neuropathy in patients with Type 2 diabetes mellitus

AIMS

Limited data are available on determinants of diabetic neuropathy as its pathogenesis is multifactorial. Since homocysteine exhibits toxic effects on vascular endothelial cells, the association between homocysteine and the prevalence of neuropathy in Type 2 diabetes mellitus was investigated.

METHODS

A total of 65 Type 2 diabetic patients were consecutively enrolled into the study. Neuropathy was diagnosed according to clinical symptoms, clinical examination, electrophysiological sensory testing and autonomic function testing. With regard to homocysteine-related parameters, plasma homocysteine, folate, vitamin B12, vitamin B6 and renal function (creatinine, ceratinine clearance, cystatin C) were measured, and the C677T polymorphism of the methylenetetrahydrofolate reductase gene was determined.

RESULTS

Forty-three of the Type 2 diabetic patients were classified as suffering from neuropathy. Both patient groups were comparable with regard to demographic data, blood pressure, glucose metabolism, renal function and homocysteine-related vitamins. In contrast, homocysteine levels (P = 0.04) and the frequency of hyperhomocysteinemia (>or= 15 micromol/l) (P = 0.01) were significantly increased in neuropathic patients. In a logistic regression model with neuropathy as dependent variable, homocysteine (adjusted for creatinine, homocysteine-related vitamins, HbA1c and duration of diabetes) was the only significant variable associated with the prevalence of neuropathy (odds ratio for homocysteine per 5 micromol/l increase: 2.60 (95% confidence interval 1.07-6.33)).

CONCLUSION

The data indicate that homocysteine is independently associated with the prevalence of diabetic neuropathy in a collective of Type 2 diabetic patients. A larger, prospective study would be desirable to clarify the role of homocysteine in the pathogenesis of diabetic neuropathy.

Cardiac troponin T predicts mortality in patients with end-stage renal disease

BACKGROUND

Patients with end-stage renal disease have a high risk of premature death, mainly as the result of cardiovascular disease (CVD), which is not sufficiently explained by the conventional risk factors. We therefore prospectively investigated total mortality and cardiovascular events in 102 patients on hemodialysis and assessed the prognostic value of baseline disease status and laboratory variables including total homocysteine and cardiac troponin T.

METHODS AND RESULTS

Patients were followed for 2 years or until their first event of CVD (for outcome variable cardiovascular events, n=33) or death (for outcome variable total mortality, n=28). Survival was computed by the Kaplan-Meier method. Cox proportional hazards model was used to determine independent predictors of CVD events or total mortality. Cardiac troponin T emerged as the most powerful predictor of mortality, resulting in an almost 7-fold risk increase at concentrations >0.10 ng/mL (hazard ratio 6.85, 95% CI 3. 04 to 15.45). Total homocysteine level greater than median was also associated with mortality (hazard ratio 2.44, 95% CI 1.10 to 5.40). These hazard ratios did not change substantially after adjustment for other risk factors. Significant predictors for CVD events were baseline diabetes, cerebrovascular disease, serum glucose, and triglycerides. After adjustment, only glucose and triglycerides remained significantly related to CVD events (hazard ratio with 95% CI 1.33 [1.12 to 1.57] and 1.14 [1.04 to 1.26], respectively, for a 1-mmol/L increase in concentration).

CONCLUSIONS

We conclude that total homocysteine and particularly cardiac troponin T are important predictors of mortality in patients with end-stage renal disease, whereas other laboratory variables and baseline disease status have less prognostic value.

Postprandial chylomicrons and VLDLs in severe hypertriacylglycerolemia are lowered more effectively than are chylomicron remnants after treatment with n-3 fatty acids

BACKGROUND

n-3 Fatty acids lower plasma triacylglycerols not only in the fasting state but also in the postprandial state. However, it is not known whether chylomicrons, chylomicron remnants, and VLDLs are all affected equally or whether some lipoprotein species are lowered preferentially.

OBJECTIVE

Lipoproteins, including large and small chylomicron remnants, were determined specifically with the aid of a newly developed method involving a combination of size-exclusion chromatography and fluorometric determination of retinyl palmitate, which served as a marker for exogenous fat.

DESIGN

Twelve hypertriacylglycerolemic men were treated for 6 wk with 4 capsules containing 85% fish-oil concentrate/d; each capsule contained 850 mg n-3 fatty acid ethyl esters (49.1% eicosapentaenoic acid by wt and 32.2% docosahexaenoic acid by wt). Oral-fat-tolerance tests were performed before and after the treatment. Blood samples were drawn in the fasting state and until 8 h postprandially.

RESULTS

Treatment with n-3 fatty acids reduced the fasting VLDL-triacylglycerol concentration by 44% (P < 0.05) and postprandial chylomicrons and VLDLs at 4, 6, and 8 h (P < 0.05) by 49-64% and 36-43%, respectively. Chylomicron remnants were reduced only in the late postprandial phase: large chylomicron remnants by 19% at 6 h and by 43% at 8 h (P < 0.05) and small chylomicron remnants by 31% at 8 h (P < 0.05).

CONCLUSION

n-3 Fatty acids effectively lower chylomicrons and VLDLs, but their effect on chylomicron remnants was observed only in the late postprandial phase.

[Characteristics of the hepatitis C virus and viral predictors of therapeutic response]

NATURAL HISTORY OF HEPATITIS C-INFECTION AND VIRAL CHARACTERISTICS: Hepatitis C-virus (HCV) infection is a major cause of non-A, non-B-hepatitis and, additionally, is associated with liver cirrhosis and hepato-cellular carcinoma. The high degree of chronificity of HCV-infection is reasonable due to antigenic variability of neutralizing epitopes leading to incomplete immunoresponse with subsequent virus persistence. Besides genetic variants of HCV within a virus population (quasispecies nature of HCV), different genotypes are classified being genetically and phenotypically distinct, and geographically restricted in part. Genotyping of HCV is not only important for phylogenetic and epidemiological studies, but also a predictive marker for pathogenesis and therapy. VIRAL PREDICTORS OF HCV THERAPY: In a meta-analysis of 18 therapeutical studies of chronical HCV infections, genotype 1 and high levels of viremia determined markedly the response to interferon therapy. In this context, clinical trials have proven the effect of a combined therapy with interferon and ribavirin. Especially patients with HCV genotype 1 or high levels of viremia had a real benefit from combined antiviral therapy in comparison to monotherapy with interferon. CONCLUSION AND FUTURE CONCEPTS: Besides recent concepts improving the therapeutical response to HCV infection, further effort is necessary to develop more successful strategies for eradication of hepatitis C virus. In this context, variations of interferon therapy should be evaluated (e.g. higher and daily doses, longer duration of interferon therapy, "retarded" interferon (PEG-IFN). In addition, new therapeutical concepts should be performed including a combination of interferon with other known antiviral agents (amantadine), a combination with immunomodulators (GM-CSF, thymosin alpha 1), the development of new antiviral agents (inhibitors of viral proteases, helicases and polymerases) and the exploration of anti-viral, molecular strategies (specific ribozymes, antisense oligonucleotides and DNA-vaccination). Nevertheless, the development of an effective vaccination should be the most important challenge for the future.

Analysis of the Gly40Ser polymorphism in the glucagon receptor gene in a German non-insulin-dependent diabetes mellitus population

A heterozygous polymorphism changing GGT40 (Gly) to AGT40 (Ser) in the glucagon receptor gene (GCG-R) was reported to be associated with non-insulin-dependent diabetes mellitus (NIDDM). A possible involvement of this polymorphism in impaired glucose tolerance was also suggested in a French population. However, the prevalence of this polymorphism differs markedly among different ethnic groups, whereby the results in German populations were found to be contradictory. We thus investigated the association of this mutation with NIDDM and healthy subjects in 508 German subjects (196 NIDDM, and 312 controls). None of the control subjects, but one of the NIDDM patients demonstrated the Gly40Ser polymorphism. Since no first-degree relative of the index patient had this genetic variance, a de novo mutation is suggested. Although the frequency of the Gly40Ser polymorphism in NIDDM observed in France is not confirmed in our population, this genetic variance is also evident in Germany.

Supplementation with vitamin B12 decreases homocysteine and methylmalonic acid but also serum folate in patients with end-stage renal disease

Hyperhomocysteinemia is frequently found in patients with end-stage renal disease (ESRD). Plasma total homocysteine (tHcy) concentrations may be reduced by supplementation with folic acid or combinations of folic acid, vitamin B12, and vitamin B6. Supplementation studies with vitamin B12 alone in patients with ESRD have not yet been published. In this study, we investigated the effects of intravenous injection of cyanocobalamin (1 mg/wk for 4 weeks) in ESRD patients (N = 14) with low serum cobalamin concentrations (<180 pmol/L). All patients had elevated levels of plasma tHcy, methylmalonic acid (MMA), and cystathionine before supplementation. After supplementation, plasma tHcy and MMA decreased 35% and 48%, respectively; however, cystathionine levels were unchanged. The extent of the plasma tHcy reduction tended to be influenced by the C677T polymorphism of methylenetetrahydrofolate reductase (MTHFR). Serum cobalamin increased significantly upon supplementation, whereas serum folate levels were substantially reduced by 47%. In contrast, red blood cell (RBC) folate was unchanged. This study shows that vitamin B12 supplementation effectively decreases both MMA and plasma tHcy in ESRD patients with low B12 levels. Furthermore, it illustrates the close interrelation between vitamin B12 and folate metabolism.