Risch M.,Labormedizinisches Zentrum Dr. Risch
Swiss medical weekly : official journal of the Swiss Society of Infectious Diseases, the Swiss Society of Internal Medicine, the Swiss Society of Pneumology | Year: 2010
A completely new approach to diagnose microbial agents at least one day earlier based on mass spectrometric analysis becomes possible in the microbiology laboratory: MALDI TOF: matrix-assisted laser desorption/ionisation time-of-flight. Comparison between results of the new procedure with those obtained by conventional testing is mandatory. 204 clinical isolates grown on agar plates were analysed both, by the MALDI TOF Bruker microflex apparatus and by conventional identification using the VITEK II and API systems, both from bioMérieux. Of the identified isolates, 72 were gram-positive and 130 gram-negative; 2 were yeasts (candida). Concordance was seen with 61/72 (85%) of the Gram-positive bacteria and with 115/130 (88%) of the Gram-negative bacteria. In 27 samples (13.2%), a discrepancy of the species and/or genus was obvious. The discrepancy appeared with 16 gram-negative (12.2%) and with 11 gram-positive germs (15.3%, n.s.). In the latter group, 6 samples showed discordance with Streptococcus pneumoniae (MALDI) and Streptococcus mitis/oralis (conventional identification) constellation. Among gram-negative samples, most differences occurred on the species level only, e.g. Enterobacter cloacae versus Enterobacter kobei. In 5 cases, discordance was major and appeared on the genus level: Enterobacter/Raoultella, Streptococcus/Gemella, Pseumdomonas/Burkholderia, Microbacter/Sphingomonas and Candida/Cryptococcus. The most outstanding difference was Microbacterium arborescens (MALDI TOF) and Sphingomonas paucimobilis (conventional). Molecular biological identification of two Streptococcus mitis group bacteria confirmed the erroneous diagnosis by MALDI TOF of Streptococcus pneumoniae. Good comparability between MALDI TOF analysis and conventional identification procedures (86.8%) but special caution is needed when identifying streptococcal species.
Nydegger U.E.,Labormedizinisches Zentrum Dr. Risch |
Luginbuhl M.,University of Bern |
Risch M.,Central Laboratory
Transfusion and Apheresis Science | Year: 2015
In this review the different mechanisms of aging and frailty such as DNA defects due to impaired DNA repair, inflammatory processes, disturbances of oxidative phosphorylation are discussed together with mechanisms of cell repair. Components of blood plasma, such as the growth-differentiation protein GDF11, were shown to enhance neurogenesis and to improve the vasculature in the animal cortex and to rejuvenate muscle tissue. Advances in laboratory assays allow to identify plasma proteins that may affect tissue regeneration. This new knowledge from animal research might affect transfusion practice in geriatric patients in the future. Provided it can be translated and confirmed in human research, blood products might no longer be considered only as oxygen carriers or drugs to improve hemostasis.In the present time blood transfusion (RBCs, plasma or platelets) should be directed by differentiated guidelines considering not only cut-off values of hemoglobin, platelet count or coagulation but also old age-specific biologic variation, comorbidities and the clinical context e.g. of bleeding. © 2015 Elsevier Ltd.
Ciardo D.E.,University of Zurich |
Burger S.,University of Zurich |
Lee C.,Labormedizinisches Zentrum Dr. Risch |
McCallum N.,University of Zurich
Journal of Clinical Microbiology | Year: 2010
A cefoxitin-susceptible Staphylococcus aureus strain was identified by the Cepheid GeneXpert as methicillin-resistant S. aureus (MRSA). This strain was highly unstable and rapidly lost SCCmec upon subculturing in vitro, indicating that unstable MRSA is best detected by gene amplification-based methods. Copyright © 2010, American Society for Microbiology. All Rights Reserved.
Schneider S.C.,University of Bern |
Tinguely R.,University of Bern |
Droz S.,University of Bern |
Hilty M.,University of Bern |
And 3 more authors.
Antimicrobial Agents and Chemotherapy | Year: 2015
Antibiotic resistance in Ureaplasma urealyticum/Ureaplasma parvum and Mycoplasma hominis is an issue of increasing importance. However, data regarding the susceptibility and, more importantly, the clonality of these organisms are limited. We analyzed 140 genital samples obtained in Bern, Switzerland, in 2014. Identification and antimicrobial susceptibility tests were performed by using the Mycoplasma IST 2 kit and sequencing of 16S rRNA genes. MICs for ciprofloxacin and azithromycin were obtained in broth microdilution assays. Clonality was analyzed with PCR-based subtyping and multilocus sequence typing (MLST), whereas quinolone resistance and macrolide resistance were studied by sequencing gyrA, gyrB, parC, and parE genes, as well as 23S rRNA genes and genes encoding L4/L22 ribosomal proteins. A total of 103 samples were confirmed as positive for U. urealyticum/U. parvum, whereas 21 were positive for both U. urealyticum/U. parvum and M. hominis. According to the IST 2 kit, the rates of nonsusceptibility were highest for ciprofloxacin (19.4%) and ofloxacin (9.7%), whereas low rates were observed for clarithromycin (4.9%), erythromycin (1.9%), and azithromycin (1%). However, inconsistent results between microdilution and IST 2 kit assays were recorded. Various sequence types (STs) observed previously in China (ST1, ST2, ST4, ST9, ST22, and ST47), as well as eight novel lineages, were detected. Only some quinolone-resistant isolates had amino acid substitutions in ParC (Ser83Leu in U. parvum of serovar 6) and ParE (Val417Thr in U. parvum of serovar 1 and the novel Thr417Val substitution in U. urealyticum). Isolates with mutations in 23S rRNA or substitutions in L4/L22 were not detected. This is the first study analyzing the susceptibility of U. urealyticum/U. parvum isolates in Switzerland and the clonality outside China. Resistance rates were low compared to those in other countries. We hypothesize that some hyperepidemic STs spread worldwide via sexual intercourse. Large combined microbiological and clinical studies should address this important issue. Copyright © 2015, American Society for Microbiology. All Rights Reserved.
Risch L.,Labormedizinisches Zentrum Dr. Risch |
Hess B.,Innere Medizin and Nephrologie Hypertonie
Therapeutische Umschau | Year: 2013
When it comes to interpret parameters of electrolyte balance and kidney function, it is important to keep pathophysiology and the theory on reference intervals in mind. Hyponatremia is most often caused by excess water. A low sodium concentration in urine should prompt a clinical evaluation of volume status. In case of suspected acute kidney failure, fractionated sodium excretion and fractionated urea excretion are able to provide insights on prerenal or renal origin of the disorder. Disruption in potassium homoeostasis can occur due to changes in supply or renal elimination as well as due to changes in the potassium balance between the extra- and intracellular compartments. The transtubular potassium gradient can help in the differential diagnosis of hyperkalemia. Evaluation of kidney function should begin with determination of serum creatinine, accompanied by an estimate of the glomerular filtration rate, as calculated by the CKD-EPI equation. As a consequence of non-renal determinants of serum creatinine, this equation has been shown to overestimate true GFR in elderly and hospitalized patients. This can result in overdosing of renally-cleared drugs. Clearance determinations can be of use in this context. © 2013 Verlag Hans Huber, Hogrefe AG, Bern.