Prospective study of a panfungal PCR assay followed by sequencing, for the detection of fungal DNA in normally sterile specimens in a clinical setting: a complementary tool in the diagnosis of invasive fungal disease?

We prospectively analyzed 34 clinical biopsy samples from 23 patients with a suspected invasive fungal infection by fungal culture, histology and a panfungal PCR followed by sequencing. Results were compared to the composite diagnosis according the European Organization for Research and Treatment of Cancer (EORTC) criteria. In 34 samples, culture, histology and panfungal PCR were positive in 35%, 38% and 62%, respectively. On the sample level the panfungal PCR revealed a sensitivity of 69% and a specificity of 62.5% compared to proven IFI according postoperative EORTC criteria. On patient level, the sensitivity of the PCR approach was 100%, specificity 62.5%.

How to discriminate contamination from bloodstream infection due to coagulase-negative staphylococci: a prospective study with 654 patients.

Coagulase-negative staphylococci (CoNS) are frequent contaminants of blood cultures. We aimed to evaluate the systemic inflammatory response syndrome (SIRS) criteria in patients with CoNS bacteraemia for discrimination between true bloodstream infection (BSI) and contamination. Prospective evaluation was carried out of clinical and laboratory parameters in adults with at least one positive blood culture with CoNS at the University Hospital of Basel between 2003 and 2007. Of 3060 positive blood cultures, 654 episodes of CoNS bacteraemia were identified. Of these, 232 (35%) were considered to be true BSI and 422 (65%) were considered to be contamination. Overall, 80% of study participants had at least one SIRS criterion, fever being the most common, and 49% had at least two SIRS criteria. In the multivariate analysis, independent predictors of BSI were fever or hypothermia (OR 2.93, 95% CI 1.91-4.5), tachycardia (OR 2.29, 95% CI 1.50-3.50), tachypnoea (OR 2.4, 95% CI 1.30-4.43), leucocytosis or leucopenia (OR 4.15, 95% CI 2.17-6.36) and the presence of a central venous line (OR 5.38, 95% CI 3.25-8.88). The probability of BSI increased with each additional SIRS criterion, ranging from 42.4% in patients with only one SIRS criterion to 56.7% for those with two criteria, and 72.3% for patients with three SIRS criteria. A positive blood culture with CoNS most likely represents true BSI if the patient has at least three SIRS criteria or two SIRS criteria and a central venous catheter. These simple bedside criteria may guide decision to treat, decreasing the use of glycopeptides.

Emergence of four cases of KPC-2 and KPC-3-carrying Klebsiella pneumoniae introduced to Switzerland, 2009-10.

We report four epidemiologically unrelated cases of KPC-carrying Klebsiella pneumoniae identified in Switzerland between May 2009 and November 2010. Three cases were transferred from Italy (two KPC-3, one KPC-2) and one from Greece (KPC-2). Resistance to colistin and doxycycline emerged in one KPC-3-carrying K. pneumoniae strain during therapy. These results demonstrate ongoing dissemination of KPC throughout Europe. Rapid and reliable identification of KPC and implementation of control measures is essential to limit spread.

Comparison of the DiversiLab repetitive element PCR system with spa typing and pulsed-field gel electrophoresis for clonal characterization of methicillin-resistant Staphylococcus aureus.

The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has become an increasing problem worldwide in recent decades. Molecular typing methods have been developed to identify clonality of strains and monitor spread of MRSA. We compared a new commercially available DiversiLab (DL) repetitive element PCR system with spa typing, spa clonal cluster analysis, and pulsed-field gel electrophoresis (PFGE) in terms of discriminatory power and concordance. A collection of 106 well-defined MRSA strains from our hospital was analyzed, isolated between 1994 and 2006. In addition, we analyzed 6 USA300 strains collected in our institution. DL typing separated the 106 MRSA isolates in 10 distinct clusters and 8 singleton patterns. Clustering analysis into spa clonal complexes resulted in 3 clusters: spa-CC 067/548, spa-CC 008, and spa-CC 012. The discriminatory powers (Simpson's index of diversity) were 0.982, 0.950, 0.846, and 0.757 for PFGE, spa typing, DL typing, and spa clonal clustering, respectively. DL typing and spa clonal clustering showed the highest concordance, calculated by adjusted Rand's coefficients. The 6 USA300 isolates grouped homogeneously into distinct PFGE and DL clusters, and all belonged to spa type t008 and spa-CC 008. Among the three methods, DL proved to be rapid and easy to perform. DL typing qualifies for initial screening during outbreak investigation. However, compared to PFGE and spa typing, DL typing has limited discriminatory power and therefore should be complemented by more discriminative methods in isolates that share identical DL patterns.

[Vaccination against pneumococci and influenza. How good is the evidence?]. / Impfungen gegen Pneumokokken und Influenza. Wie groß ist die Evidenz?

Diseases caused by pneumococci and influenza viruses can lead to severe complications in children, in older, chronically ill and immunosuppressed patients. In an aging population in western countries they present an important cause of morbidity and mortality. Additionally, antibiotic resistance may complicate a therapy. Consequently, the need of an effective vaccine is obvious. The 23-valent polysaccharide pneumococcal vaccine has been discussed critically. New meta-analyses do not show an efficacy in preventing invasive pneumococcal disease or death of all cause. However, a very recent study has shown a significant reduction of pneumonias and death due to pneumococcal disease in nursing-home residents. The 7-valent conjugated vaccine is more immunogenic and efficient in children and first studies demonstrate its efficacy in immunosuppressed persons. In Switzerland this latter vaccine is used in children, in Germany the 7-valent vaccine has been replaced by the 13-valent conjugated vaccine since December 2009. Influenza-vaccines are effective, while vaccines with an adjuvance seem more immunogenic, in particular in older persons. The 2010/2011 influenza vaccine has been adapted and includes the pandemic influenza H1N1 2009 strain. The influenza vaccine often does not provide protection against infection, however, it does provide good efficacy against severe complications related to influenza.