Sandra Witteveen

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The main virulence factor of Streptococcus pneumoniae is the capsule. The polysaccharides comprising this capsule are encoded by approximately 15 genes and differences in these genes result in different serotypes. The aim of this study was to investigate the sequence diversity of the capsular genes of serotypes 6A, 6B, 6C, 19A and 19F and to explore a(More)
The introduction of nationwide pneumococcal vaccination may lead to serotype replacement and the emergence of new variants that have expanded their genetic repertoire through recombination. To monitor alterations in the pneumococcal population structure, we have developed and utilized Capsular Sequence Typing (CST) in addition to Multiple-Locus Variable(More)
Recently, there has been an increase in The Netherlands in the number of cases of invasive disease caused by Haemophilus influenzae serotype b (Hib). To study a possible change in the Hib population that could explain the rise in incidence, a multiple-locus variable number tandem repeats analysis (MLVA) was developed to genotype H. influenzae isolates. The(More)
A method is described in which the extent of myocardial infarction in man is assessed by mathematical analysis of the rise in plasma enzyme levels after infarction. Five enzymes are used in this study: lactate dehydrogenase (LDH); alpha-hydroxybutyrate dehydrogenase (alpha-HBDH); aspartate aminotransferase (GOT); creatine phosphokinase (CPK); and(More)
Studies of the three human creatine phosphokinase (EC isoenzymes, MM, MB, and BB, show that important differences exist in substrate dependency of the reaction rates. A method was developed to study these properties in which the ATP formed in the reverse reaction was measured by means of firefly luciferase. With substrate conditions at which the(More)
UNLABELLED Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) was detected in 2003 and rapidly became the predominant MRSA clade in the Netherlands. Studies have shown that transmissions are difficult to identify, since this MRSA variant represents a genetically homogenous clade when current typing techniques are used. Here,(More)
Serial plasma enzyme determinations were carried out in 32 patients who underwent cardiac surgery with the aid of extracorporeal circulation. Plasma creatine kinase (CK), the cardiospecific isoenzyme of CK (CKMB), and alpha-hydroxybutyrate dehydrogenase (HBDH) were determined from the onset of surgery up to 100 to 120 hours after operation. From the plasma(More)
In the Netherlands, the number of cases of infection with New Delhi metallo-beta-lactamase (NDM)-positive Enterobacteriaceae is low. Here, we report an outbreak of NDM-1-producing Klebsiella pneumoniae infection in a Dutch hospital with interspecies transfer of the resistance plasmid and unexpected occurrence in other unrelated health care centers (HCCs).(More)
Using a two-compartment model with continuous input function, the rate and extent of myocardial damage were calculated from plasma enzyme levels measured in patients suffering from acute myocardial infarction (AMI). Results were compared for four different enzymes. As regards the course of necrosis, two different hypotheses were tested and it was shown that(More)
In 18 patients, myocardial injury was estimated by mathematical analysis of the rise in plasma activity of alpha-hydroxybutyrate (alpha-HBDH) dehydrogenase as observed by multiple sampling after admission. This enzyme represents the lactate dehydrogenase isoenzymes LDH1 and LDH2. Changes in plasma volume were assessed by determining hematocrit values at the(More)