Comparison of two commercial broadrange PCR and sequencing assays for identification of bacteria in culture-negative clinical samples

Abstract Background Culturing has long been the gold standard for detecting aetiologic agents in bacterial infections. In some cases, however, culturing fails to detect the infection. To further investigate culture-negative samples, amplification and subsequent sequencing of the 16S rRNA gene is often applied. The aim of the present study was to compare the current method used at our Department of Clinical Microbiology, based on the MicroSeq ID system (Applied Biosystems, USA) with the Universal Microbe Detection (UMD) SelectNA kit (Molzym, Germany). Methods 76 culture-negative samples were first processed with the MicroSeq ID analysis, where total DNA was extracted and the 16S gene amplified and sequenced with the MicroSeq ID system. Samples were subsequently processed with the UMD SelectNA analysis, where human DNA was removed during the DNA extraction procedure and the 16S gene amplified in a real-time PCR and sequenced. Results 22 of 76 samples (28.9%) were positive for bacteria with the UMD SelectNA, which was significantly more (p = 0.0055) than the MicroSeq ID where 11 of 76 samples (14.5%) were positive. The UMD SelectNA assay identified more relevant bacterial pathogens than the MicroSeq ID analysis (p = 0.0233), but also found a number of species that were considered contaminations. Conclusions The UMD SelectNA assay was valuable for the identification of pathogens in culture-negative samples; however, due to the sensitive nature of the assay, extreme care is suggested in order to avoid false positives

Infective Arthritis: Bacterial 23S rRNA Gene Sequencing as a Supplementary Diagnostic Method

Consecutively collected synovial fluids were examined for presence of bacterial DNA (a 700-bp fragment of the bacterial 23S rRNA gene) followed by DNA sequencing of amplicons, and by conventional bacteriological methods. One or more microorganisms were identified in 22 of the 227 synovial fluids (9,7%) originating from 17 patients. Sixteen of the patients had clinical signs of arthritis. For 11 patients molecular and conventional bacterial examinations were in agreement. Staphylococcus aureus, Streptococcus dysgalactiae subspecies equisimilis and Streptococcus pneumoniae, were detected in synovial fluids from 6, 2 and 2 patients, respectively. In 3 patients only 23S rRNA analysis was positive; 2 synovial fluids contained S. dysgalactiae subspecies equisimilis and 1 S. pneumoniae). The present study indicates a significant contribution by PCR with subsequent DNA sequencing of the 23S rRNA gene analysis in recognizing and identification of microorganisms from synovial fluids

<em>Cardiobacterium hominis</em> and <em>Cardiobacterium valvarum</em>:Two case stories with infective episodes in pacemaker treated patients

INTRODUCTION: Cardiobacterium hominis and Cardiobacterium valvarum are well known, though rare, etiologic agents of infective endocarditis. Cardiac devices are increasingly implanted. CASE REPORTS: Two cases of infective episodes in pacemaker (PM) treated patients with respectively C. hominis and C. valvarum are presented. In one case blood-culture bottles yielded growth of C. hominis at two episodes with two years apart. At the second episode a vegetation was recognized at the PM lead and the PM device and lead was removed. In the C. valvarum case, echocardiography revealed a bicuspid aortic valve with severe regurgitation and a more than 1 cm sized vegetation. CONCLUSION: The cases illustrate the diversity in disease severity by Cardiobacterium species. Careful follow up has to be performed in order not to overlook a relatively silent relapsing infection

Wirtschaften. Kulturwissenschaftliche Perspektiven.

Unter dem Titel „Wirtschaften. Kulturwissenschaftliche Perspektiven“ fand 2017 in Marburg der 41. Kongress der Deutschen Gesellschaft für Volkskunde (dgv) auf Einladung des Instituts für Europäische Ethnologie / Kulturwissenschaft der Philipps-Universität Marburg statt. Die vorliegende Publikation liefert eine umfassende Dokumentation der auf dem Kongress diskutierten Beiträge