Dieter Mitteregger

High expression of lipoprotein lipase in poor risk B-cell chronic lymphocytic leukemia.

We investigated the pattern of lipoprotein lipase (LPL) expression in B-cell chronic lymphocytic leukemia (B-CLL) and assessed its prognostic relevance. Expression of LPL mRNA as well as protein was highly restricted to leukemic B cells. The intensity of intracellular immunoreactivity of LPL was higher in samples of patients with unmutated immunoglobulin heavy-chain variable region genes (IGVH) compared to those with mutated IGVH genes. LPL mRNA levels in peripheral blood mononuclear cells (PBMNC) from 104 CLL patients differed by 1.5 orders of magnitude between cases with mutated (N=51) or unmutated (N=53) IGVH (median: 1.33 vs 45.22 compared to normal PBMNC). LPL expression correlated strongly with IGVH mutational status (R=0.614; P<0.0001). High LPL expression predicted unmutated IGVH status with an odds ratio of 25.90 (P<0.0001) and discriminated between mutated and unmutated cases in 87 of 104 patients (84%). LPL expression was higher in patients with poor risk cytogenetics. High LPL expression was associated with a shorter treatment-free survival (median 40 vs 96 months, P=0.001) and a trend for a shorter median overall survival (105 months vs not reached). Our data establish LPL as a prognostic marker and suggest functional consequences of LPL overexpression in patients with B-CLL.

Utility of sepsis biomarkers and the infection probability score to discriminate sepsis and systemic inflammatory response syndrome in standard care patients.

Physicians are regularly faced with severely ill patients at risk of developing infections. In literature, standard care wards are often neglected, although their patients frequently suffer from a systemic inflammatory response syndrome (SIRS) of unknown origin. Fast identification of patients with infections is vital, as they immediately require appropriate therapy. Further, tools with a high negative predictive value (NPV) to exclude infection or bacteremia are important to increase the cost effectiveness of microbiological examinations and to avoid inappropriate antibiotic treatment. In this prospective cohort study, 2,384 patients with suspected infections were screened for suffering from two or more SIRS criteria on standard care wards. The infection probability score (IPS) and sepsis biomarkers with discriminatory power were assessed regarding their capacity to identify infection or bacteremia. In this cohort finally consisting of 298 SIRS-patients, the infection prevalence was 72%. Bacteremia was found in 25% of cases. For the prediction of infection, the IPS yielded 0.51 ROC-AUC (30.1% sensitivity, 64.6% specificity). Among sepsis biomarkers, lipopolysaccharide binding protein (LBP) was the best parameter with 0.63 ROC-AUC (57.5% sensitivity, 67.1% specificity). For the prediction of bacteremia, the IPS performed slightly better with a ROC-AUC of 0.58 (21.3% sensitivity, 65% specificity). Procalcitonin was the best discriminator with 0.78 ROC-AUC, 86.3% sensitivity, 59.6% specificity and 92.9% NPV. Furthermore, bilirubin and LBP (ROC-AUC: 0.65, 0.62) might also be considered as useful parameters. In summary, the IPS and widely used infection parameters, including CRP or WBC, yielded a poor diagnostic performance for the detection of infection or bacteremia. Additional sepsis biomarkers do not aid in discriminating inflammation from infection. For the prediction of bacteremia procalcitonin, and bilirubin were the most promising parameters, which might be used as a rule for when to take blood cultures or using nucleic acid amplification tests for microbiological diagnostics.

Neutralization of Antimicrobial Substances in New BacT/Alert FA and FN Plus Blood Culture Bottles

ABSTRACT Time to detection (TTD) in automated blood culture systems is delayed for sensitive microorganisms in the presence of antimicrobial substances and has been associated with worse outcomes for sepsis patients on inadequate empirical therapy. While resin addition removes antimicrobial substances to various degrees from blood culture media, media formulations and the blend of resins may influence performance. The BacT/Alert 3D system (bioMérieux) was investigated using the new resin-containing medium types FA Plus (aerobic) and FN Plus (anaerobic). TTD was compared between control and test bottles containing relevant bacteria or Candida albicans, with and without defined concentrations of antimicrobials. Failure of neutralization was defined as a negative blood culture on day 3. In general, growth delay was nonlinear, concentration dependent, bottle type specific, and reciprocally associated with MICs. Substance-specific serum drug concentrations corresponding to a predefined, clinically relevant 3-h delay of TTD were calculated. Where appropriate, a time interval allowing for drug elimination below this critical level was obtained by pharmacokinetic modeling. Clarithromycin, clindamycin, gentamicin, linezolid, tigecycline, vancomycin, and fluconazole were neutralized. For ciprofloxacin and piperacillin-tazobactam, which were only incompletely neutralized in combination with the most sensitive test strains, a maximum waiting time for blood draw of 1 h was determined based on pharmacokinetics. One or more test strains did not grow in bottles containing either amoxicillin-clavulanate, cefepime, cefotaxime, meropenem, or metronidazole, and we thus recommend particular caution in timing of blood draws if patients have been pretreated with these agents.

NOTCH2 links protein kinase C delta to the expression of CD23 in chronic lymphocytic leukaemia (CLL) cells

One characteristic of chronic lymphocytic leukaemia (CLL) lymphocytes is high expression of CD23, which has previously been identified as a downstream target for NOTCH2 signalling. The mechanisms regulating NOTCH2‐dependent CD23 expression, however, are largely unknown. This study showed that peripheral CLL cells overexpressed transcriptionally active NOTCH2 (N2IC), irrespective of their prognostic marker profile. When placed in culture, NOTCH2 activity was spontaneously decreased in 25 out of 31 CLL cases (81%) within 24 h. DNA‐bound N2IC complexes could be maintained by the protein kinase C (PKC) activator phorbol 12‐myristate 13‐acetate (PMA) or by γ‐interferon (IFN‐γ), two CLL characteristic inducers of CD23 expression. Inhibition of PKC‐δ by RNA interference or by rottlerin antagonised PMA‐induced NOTCH2 activation and also suppressed NOTCH2 activity in CLL cases with constitutively activated NOTCH2 signalling. In 23 out of 29 CLL cases tested (79%), DNA‐bound N2IC complexes were found to be resistant to the γ‐secretase inhibitor (GSI) DAPT, suggesting that GSIs will be only effective in a subset of CLL cases. These data suggest that deregulation of NOTCH2 signalling is critically involved in maintaining the malignant phenotype of CLL lymphocytes and point to a link between PKC‐δ and NOTCH2 signalling in the leukemic cells.

Sepsis biomarkers in neutropaenic systemic inflammatory response syndrome patients on standard care wards

Neutropaenic patients are at a high risk of contracting severe infections. In particular, in these patients, parameters with a high negative predictive value are desirable for excluding infection or bacteraemia. This study evaluated sepsis biomarkers in neutropaenic patients suffering from systemic inflammatory response syndrome (SIRS). Further, the predictive capacities of evaluated biomarkers in neutropaenic SIRS patients were compared to non‐neutropaenic SIRS patients.

Evaluation of the Septifast MGrade Test on Standard Care Wards--A Cohort Study.

Background The immediate need for appropriate antimicrobial therapy in septic patients requires the detection of the causative pathogen in a timely and reliable manner. In this study, the real-time PCR Septifast MGrade test was evaluated in adult patients meeting the systemic inflammatory response syndrome (SIRS) criteria that were treated at standard care wards. Methods Patients with clinical suspected infection, drawn blood cultures (BC), the Septifast MGrade test (SF) and sepsis biomarkers were prospectively screened for fulfillment of SIRS criteria and evaluated using the criteria of the European Centre of Disease Control (ECDC) for infection point prevalence studies. Results In total, 220 patients with SIRS were prospectively enrolled, including 56 patients with detection of bacteria in the blood (incidence: 25.5%). BC analysis resulted in 75.0% sensitivity (95% confidence interval, CI: 61.6%– 85.6%) with 97.6% specificity (CI: 93.9%– 99.3%) for detecting bacteria in the blood. In comparison to BC, SF presented with 80.4% sensitivity (CI: 67.6%– 89.8%) and with 97.6% specificity (CI: 93.9%– 99.3%). BC and SF analysis yielded comparable ROC-AUCs (0.86, 0.89), which did not differ significantly (p = 0.558). A trend of a shorter time-to-positivity of BC analysis was not seen in bacteremic patients with a positive SF test than those with a negative test result. Sepsis biomarkers, including PCT, IL-6 or CRP, did not help to explain discordant test results for BC and SF. Conclusion Since negative results do not exclude bacteremia, the Septifast MGrade test is not suited to replacing BC, but it is a valuable tool with which to complement BC for faster detection of pathogens.

Non-linear significant relationship between use of glycopeptides and isolation of vancomycin-resistant Enterococcus species in a university hospital setting

BackgroundEmergence of colonization and infection with vancomycin-resistant enterococci (VRE) has become a worldwide challenge. To investigate whether the increasing incidence of VRE isolation can be correlated with use of glycopeptides in the hospital setting, we conducted a hospital-wide two-year study in the university hospital of Vienna.MethodsWithin the period from January 2011 through December 2012 all patients with isolation of invasive or non-invasive VRE were retrospectively included. Specialty-specific data concerning the consumption of vancomycin and teicoplanin, fluoroquinolones and third generation cephalosporins in defined daily doses (DDDs) from June 2010 through May 2012 were extracted from the hospital pharmacy computer system. To assess the relationship between the usage of those antibiotics and the incidence of VRE (VRE-rate per 10 000 patients) a Poisson regression was performed.FindingsIn the study period 266 patients were colonized or infected with VRE. Specialty-specific VRE isolation was as follows: general surgical units (44 patients), bone marrow transplant unit (35 patients), general medical units (33 patients), cardiothoracic surgery (27 patients), nephrology (26 patients), haematooncology (22 patients), gastroenterology (17 patients), urology (17 patients), and the infectious diseases unit (11 patients). Hospital-wide consumption of glycopeptides was higher for teicoplanin than for vancomycin (26 242 versus 8677 DDDs). Specialty-specific VRE incidence significantly increased with the use of glycopeptides, fluoroquinolones or third generation cephalosporins (p < 0.001). The results of the Poisson regression for vancomycin (p = 0.0018) and teicoplanin (p < 0.0001) separately were both highly significant. Spearman’s correlation coefficient indicated a strong correlation between the two variables (rho = 0.8).ConclusionOverall usage of glycopeptides, fluoroquinolones or third generation cephalosporins contributed to the emergence of VRE in the hospital setting.

High diversity of beta-lactamases in the General Hospital Vienna verified by whole genome sequencing and statistical analysis.

The detailed analysis of antibiotic resistance mechanisms is essential for understanding the underlying evolutionary processes, the implementation of appropriate intervention strategies and to guarantee efficient treatment options. In the present study, 110 β-lactam-resistant, clinical isolates of Enterobacteriaceae sampled in 2011 in one of Europes largest hospitals, the General Hospital Vienna, were screened for the presence of 31 β-lactamase genes. Twenty of those isolates were selected for whole genome sequencing (WGS). In addition, the number of β-lactamase genes was estimated using biostatistical models. The carbapenemase genes blaKPC-2, blaKPC-3, and blaVIM-4 were identified in carbapenem-resistant and intermediate susceptible isolates, blaOXA-72 in an extended-spectrum β-lactamase (ESBL)-positive one. Furthermore, the observed high prevalence of the acquired blaDHA-1 and blaCMY AmpC β-lactamase genes (70%) in phenotypically AmpC-positive isolates is alarming due to their capability to become carbapenem-resistant upon changes in membrane permeability. The statistical analyses revealed that approximately 55% of all β-lactamase genes present in the General Hospital Vienna were detected by this study. In summary, this work gives a very detailed picture on the disseminated β-lactamases and other resistance genes in one of Europes largest hospitals.

Anaplasmataceae-Specific PCR for Diagnosis and Therapeutic Guidance for Symptomatic Neoehrlichiosis in Immunocompetent Host

Candidatus Neoehrlichia is increasingly being recognized worldwide as a tickborne pathogen. We report a case of symptomatic neoehrlichiosis in an immunocompetent Austria resident who had recently returned from travel in Tanzania. The use of Anaplasmataceae-specific PCR to determine the duration of antimicrobial therapy seems reasonable to avert recrudescence.

Successful implementation of infection control strategies prevents P. aeruginosa transmission among cystic fibrosis patients inside the hospital

Background: The aim of this study was to characterise the epidemiology of P. aeruginosa isolated from cystic fibrosis (CF) patients at the Vienna General Hospital (VGH) by molecular genetic fingerprinting in order to understand transmission ways and to evaluate the established infection control protocols. Methods: The outpatient clinic for CF patients at the VGH cares for children and adolescents up to the age of 18 years. Among an average of 139 patients cared for at the clinic, 41 were tested positive for P. aeruginosa during the study period. Fifty P. aeruginosa isolates, obtained between August 2010 and March 2012 from routine examinations of CF patients, were subject to molecular characterization using the DiversiLab® method. Results: 42 distinguishable molecular-biological patterns were identified, 7 of which were found multiple times. 40 out of 42 genotypes were retrieved from single patients only, while two patterns were present in two patients each. Nine patients presented with two or more phenotypically diverse P. aeruginosa isolates. In five of these cases the retrieved isolates belonged to the same genotype. Conclusion: The broad genetic heterogeneity of P. aeruginosa in the studied patient population suggests that the majority of CF patients cared for at the VGH acquire P. aeruginosa from environmental sources. It may be concluded that implemented infection control guidelines have been successful in preventing nosocomial transmission of P. aeruginosa among CF patients within the VGH and patient-to-patient transmission outside the hospital. Chronic polyclonal infection/colonization was rare in the study population.