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Biomedical subjects

S Van Lierde

Publications and source records attributed to S Van Lierde.

At least 19 recordsLinked to original sources
PubMed1999

Increase in penicillin resistance rates in Belgium due to clonal spread of a penicillin-resistant 23F Streptococcus pneumoniae strain.

In 1994 a sudden increase in penicillin resistance was observed in Belgium among invasive pneumococci. To determine whether this increase was due to clonal spread of a resistant strain or to de novo acquisition of penicillin resistance, pneumococci of capsular types 23F, 19, 14, 9, and 6 isolated in 1993 and 1994, were analyzed by capsular serotyping and DNA macrorestriction analysis, resolved by pulsed-field gel electrophoresis. Furthermore, pneumococcal isolates from northern France, a region with a high prevalence of penicillin resistance, and from southern Belgium, a region with a low but increasing prevalence of penicillin resistance, were analyzed. The rate of resistance of invasive pneumococci to penicillin increased from 2.3% in 1993 to 7.6% in 1994. Pneumococcal serotype 23F represented 26.7% of the penicillin-resistant isolates in 1993 and 40.4% in 1994, while the prevalence of serotype 23F decreased from 10.9% in 1993 to 8.8% in 1994. In 1994 up to 35.8% of serotype 23F isolates were penicillin resistant. The Belgian penicillin-resistant 23F isolates from 1994 were genetically closely related to the French 23F penicillin-resistant isolates and, as clones were clearly distinct from the other serotypes as well as from the penicillin-susceptible 23F isolates. These data demonstrate the important contribution of the clonal spread of a penicillin-resistant pneumococcal strain in the overall increase of penicillin resistance in our country.

Belgium↗
PubMed1999

Staphylococcus aureus adherence to nasal epithelial cells in a physiological in vitro model.

Nasal carriage of Staphylococcus aureus represents a risk factor for subsequent invasive infections and interpatient transmission of strains. No physiological in vitro model of nasal epithelial cells is available to study both patient- and bacteria-related characteristics and their interaction, leading to adherence and colonization. Starting with tissues from human nasal polyps, a confluent, squamous, nonkeratinized epithelium in collagen-coated 96-well microtiter plates was obtained after 14 d. This in vitro cell-layer was characterized histologically, ultrastructurally, and immunohistochemically and showed features that were indistinguishable from those observed in the squamous nonkeratinized epithelium found in the posterior part of the vestibulum nasi. Adherence experiments were performed with four different 3H-thymidine-labeled Staphylococcus aureus strains. The effect of bacterial inoculum size, temperature of incubation, and incubation medium were studied. The adherence results were found to be reproducible, reliable and sensitive, allowing detection of small quantitative differences in adherence between the Staphylococcus aureus strains. There was no significant difference in adherence at 23 degrees C and 37 degrees C, nor between the incubation medium M199 and phosphate-buffered saline. Plastic adherence could be reduced and standardized with use of siliconized tips and a constant bacterial inoculum volume of 100 microl/well. This physiological and reliable in vitro cell-culture model offers a unique opportunity to study Staphylococcus aureus adherence to squamous, nonkeratinized nasal epithelial cells and both patient and bacterial characteristics involved in this interaction.

Bacterial Adhesion↗
PubMed1999

Foreign body infection: a new rat model for prophylaxis and treatment.

A subcutaneous catheter model in the rat was developed that allowed the study of prevention and treatment strategies for foreign body infection. In contrast to earlier models, the foreign body was inoculated with a low inoculum of Staphylococcus epidermidis just before implantation, thus mimicking intraoperative contamination with skin flora. Reproducible infection of all catheters followed if no prophylaxis was given. However, foreign body infection could be prevented or treated with antibiotics such as teicoplanin, which was marginally effective, and rifampicin, which proved very effective.

Animals↗
PubMed1998

Somatic triple mosaicism in a carrier of X-linked chronic granulomatous disease.

The X-linked form of chronic granulomatous disease (CGD) is caused by mutations in the CYBB gene, which encodes the 91-kD subunit of the flavocytochrome b558, a component of the superoxide-generating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in phagocytic leukocytes. Mutations in this gene are very heterogeneous and often unique for one family. Here we report on a family with two patients (brothers), one with a 3-kb deletion comprising exon 5 and the other with a 3.5-kb deletion comprising exons 6 and 7 of the CYBB gene. Sequence analysis of polymerase chain reaction (PCR)-amplified genomic DNA proved these deletions to be overlapping for 35 bp. Analysis by restriction fragment length polymorphism of genomic DNA from the mother's leukocytes showed her to be a carrier of both deletions in addition to the normal CYBB sequence. This triple somatic mosaicism was confirmed with PCR-amplified genomic and complementary DNA. The presence of the normal CYBB gene in the mother was also proven by the finding of normal superoxide-generating neutrophils in addition to cells lacking this ability. Triple X syndrome was excluded. These findings suggest that the mutations are the result of an event in early embryogenesis of the mother, possibly involving a mechanism like sister chromatid exchange.

Adolescent↗
PubMed1998

Response to bronchodilators in clinically stable 1-year-old patients with bronchopulmonary dysplasia.

UNLABELLED: Bronchodilators are often used in the treatment of patients with bronchopulmonary dysplasia (BPD). However, few studies evaluate their efficacy in patients with stable disease beyond the newborn period. Therefore, pulmonary function was measured before and after aerosol treatment with salbutamol (0.25 ml Ventolin 0.5%) and subsequently after aerosol with ipratropium bromide (0.25 ml Atrovent 0.025%). Studies were performed at the corrected postnatal age of 52 +/- 2 weeks in 52 patients who had been ventilated after birth because of newborn lung disease. Twenty-two of these 52 patients had developed BPD. Pulmonary function was measured after sedation and using the PEDS system. Expiratory resistance (median 52.1 versus 39.1 cmH2O/l/s; P < .008) and inspiratory resistance (median 42.5 vs 27.8 cmH2O/l/s; P < .04) were significantly worse in BPD patients at the age of 1 year. Half of the BPD patients had a decrease in pulmonary resistance after salbutamol. However, there was no statistically significant decrease in pulmonary resistance after salbutamol or ipratropium in the BPD patients as a group. After salbutamol pulmonary resistance significantly worsened in the patients who did not develop BPD. CONCLUSION: Although individual patients may benefit, routine administration of bronchodilators seems not warranted in stable BPD patients at the age of 1 year.

Administration, Inhalation↗
PubMed1997

Bronchopulmonary dysplasia: correlation of radiographic and clinical findings.

BACKGROUND AND PURPOSE: Abnormalities of the chest wall have been described in bronchopulmonary dysplasia (BPD). Clinical, radiographic and pulmonary function variables were evaluated in 1-year-old children ventilated because of neonatal lung disease in order to quantify these thoracic changes and to evaluate the lung disease. METHODS: The pulmonary status of 51 infants with neonatal lung disease requiring artificial ventilation was reevaluated clinically and radiographically at the age of 1 year. Twenty-two of these infants had developed BPD. Thoracic depth and width were measured clinically and on chest X-ray. The Toce score evaluated the presence of cardiomegaly, hyperinflation, emphysema and interstitial lung disease. Lung function was measured after sedation using previously reported methods. In BPD patients, Toce score and lung function were determined and compared at 1 month and at 1 year of age. RESULTS: In BPD patients, chest depth was significantly smaller when measured clinically as well as on chest radiograph (P < 0.05; Mann-Whitney U-test). There was a statistically significant correlation between chest depth measured clinically and on chest X-ray. Toce score was significantly higher in BPD patients (P < 0.05). In BPD patients intersitial abnormalities and decreased lung compliance were more frequent at the age of 1 month than at the age of 1 year. At the age of 1 year, hyperinflation was more frequent and at that time increased airway resistance was still noted. Thus the type of X-ray abnormality reflects the type of lung function disturbance. CONCLUSION: The flatness of the chest is most likely a consequence of the long-standing lung function abnormalities.

Bronchopulmonary Dysplasia↗
PubMed1997

Respiratory syncytial virus bronchiolitis: a double-blind dexamethasone efficacy study.

The efficacy of dexamethasone therapy for primary respiratory syncytial virus bronchiolitis was studied in a double-blind placebo design in 29 previously healthy infants (median age, 194 days). No significant differences were found between the groups in evolution of respiratory rate, oxygen saturation, clinical score, or pulmonary function tests on day 3.

Analysis of Variance↗
PubMed1997

Toxic shock syndrome without rash in a young child: link with syndrome of hemorrhagic shock and encephalopathy?

A diffuse macular erythroderma and subsequent desquamation after 1 to 2 weeks are two of the five major diagnostic criteria of toxic shock syndrome (TSS). We present the case of a 15-month-old girl with TSS, but without erythroderma or desquamation. She was admitted with high fever, shock, and multiorgan involvement. Minimal or no cutaneous signs were present. Initially the diagnosis of the syndrome of hemorrhagic shock and encephalopathy was made. After 7 days, a TSS toxin 1-producing strain of Staphylococcus aureus was cultured from an inguinal lymph node, where inflammation had already been noticed on admission. Moreover, the girl had no antibodies against this toxin. The serum cytokine profile during the acute phase of her illness showed high levels of tumor necrosis factor-alpha, interleukin-6 and interferon-gamma, as is seen during activation of the immune system by TSS toxin 1. Other possible causes for the patient's illness were excluded. We conclude that the patient had TSS without rash. Without the evidence implicating a TSS toxin 1-producing strain of S. aureus as the cause of her disease, a diagnosis of syndrome of hemorrhagic shock and encephalopathy would have been made. It is possible that some cases of syndrome of hemorrhagic shock and encephalopathy represent a variant of TSS in small children.

Bacterial Toxins↗
PubMed1997

Origin and transmission of methicillin-resistant Staphylococcus aureus in an endemic situation: differences between geriatric and intensive-care patients.

Imported vs. hospital-acquisition of MRSA was assessed in > 6000 patients at a large tertiary care teaching hospital. About five percent (5.1%) of patients carried MRSA on admission, mostly without clinical symptoms; the highest percentage (11.6%) being in geriatric patients. Hospital-acquisition of MRSA occurred in 1.7% of patients and was particularly high in intensive-care units (5.2%). Phenotype and genotype analysis of 158 MRSA strains isolated from 61 patients revealed a cluster of closely related strains in the hospital-acquired MRSA infections and the close relationship of this cluster to the regional epidemic MRSA strain. The MRSA strains imported by geriatric patients were genetically different, did not spread between geriatric patients and were only a minor source of nosocomial infection.

Age Distribution↗
PubMed1997

Polyclonal staphylococcus endocarditis.

Coagulase-negative staphylococcus (CNS) is the most frequent cause of nosocomial bacteremia and prosthetic valve endocarditis. CNS bacteremia can be polyclonal. No data exist on the clonality of CNS causing endocarditis. We present a case of CNS aortic homograft endocarditis in which at least five different genotypes of CNS were identified in initial blood-culture isolates by genomic macrorestriction enzyme analysis and pulsed field gel electrophoresis. Since the polyclonality was accompanied by differences in antibiotic susceptibility, this observation may have important consequences for the treatment of CNS endocarditis. Because of the parallels in the pathogenesis of CNS prosthetic valve endocarditis and CNS infections of a variety of other prosthetic devices, it might also have consequences for CNS prosthetic device infections in general. We suggest that antibiotic susceptibility testing of just one blood-culture isolate may be insufficient.

Coagulase↗
PubMed1997

Clonal analysis and identification of epidemic strains of methicillin-resistant Staphylococcus aureus by antibiotyping and determination of protein A gene and coagulase gene polymorphisms.

Forty-three methicillin-resistant Staphylococcus aureus (MRSA) isolates with known genetic and epidemiological relatedness and different degrees of transmission were analyzed by antibiotyping, protein A gene polymorphism analysis, and coagulase gene polymorphism analysis. The three typing systems were evaluated for their performance and convenience to define clones and to discriminate between epidemic MRSA (EMRSA) and sporadic MRSA (SMRSA). Antibiotyping and AluI restriction fragment length polymorphism analysis of the coagulase gene were able to define clones in the same way as DNA macrorestriction analysis (SmaI). However, both techniques presented disadvantages, making neither of them useful as a single typing method. Protein A gene polymorphism analysis appeared to be of no value for clonal analysis. None of the three typing methods was able to differentiate between EMRSA and SMRSA.

Bacterial Typing Techniques↗
PubMed1995

Effect of neurotropin on cerebral edema, calcium and other elements in mice subarachnoidally injected with carrageenan.

Neurotropin, an inhibitor of the kallikrein-kinin system, was therapeutically i.p. administered to mice with brain inflammation induced by subarachnoidal injection of carrageenan. Brain water content was determined by the wet/dry weight ratio. The concentrations of cerebral Ca, K, Mn, Fe, Cu, Zn, Se, Rb, and Sr were measured by particle-induced X-ray emission. It was found that neurotropin dose dependently reduced brain water content. The mean concentration of cerebral calcium was significantly lower in the neurotropin-treated group than that in the non-treated group, suggesting less cell damage. Since it has been reported that dexamethasone and some prostaglandin inhibitors have no effect on brain swelling in this model and that, in contrast to these drugs, neurotropin has only a weak inhibiting activity on carrageenan-induced paw swelling, it is hypothesized that the kallikrein-kinin system is differently implicated in cerebral and peripheral inflammation.

Analgesics↗
PubMed1994

Pulmonary mechanics during respiratory distress syndrome in the prediction of outcome and differentiation of mild and severe bronchopulmonary dysplasia.

Pulmonary mechanics was prospectively and longitudinally studied in a cohort of 58 infants who suffered from respiratory distress syndrome. The aim was to determine if early compliance and resistance measurements had additional value to simple clinical variables in predicting poor outcome ie nonsurvival or severe bronchopulmonary dysplasia (BPD) at 28 days. Second, we wanted to determine whether and when the recently described type 1 (mild) BPD and type 2 (severe) BPD could be differentiated by means of lung function tests. In a logistic model, neither lung compliance nor pulmonary resistance at days 1 and 4 of life were selected as predictive variables. On the other hand, gestational age and the ventilatory index no. 1 (ventilator frequency x maximal inspiratory pressure) on day 3 were the best early predictors of poor outcome. Type 2 BPD was characterized by a lower lung compliance and a higher pulmonary resistance than type 1 BPD, although the differences were only significant at 28 days. In conclusion, pulmonary function tests were not helpful in the early prediction of poor outcome at 28 days. They might, however, be of value in the follow-up of BPD patients after 28 days.

Age Factors↗
PubMed1994

Flat chest in survivors of bronchopulmonary dysplasia.

Pulmonary mechanics as well as chest wall width and depth were measured in 52 1-year-old survivors of newborn lung disease. Of the 52 patients examined, 22 had developed bronchopulmonary dysplasia (BPD). Chest wall depth was significantly less in the patients who survived with development of BPD compared with those who did not develop BPD. Pulmonary resistance and chest wall width-to-depth ratio were significantly increased in the patients with BPD. Because the chest wall of infants is highly compliant, we suggest that the flatter chest in patients with BPD could result from the abnormal pulmonary mechanics.

Bronchopulmonary Dysplasia↗
PubMed1993

More than tenfold increase of arsenic in serum and packed cells of chronic hemodialysis patients.

Arsenic concentrations were determined in serum and packed cells of 7 chronic hemodialysis patients, in fresh dialysate and in a heparin solution. The analytical technique was radiochemical neutron activation analysis. The accuracy of the method was tested by the analysis of As in certified reference materials. Patients showed elevated serum and packed cell arsenic concentrations compared with controls (serum, range: 2.3-79.8 ng As/ml, median: 11.5 ng As/ml; versus range: 0.132-4.783 ng As/ml, median: 0.38 ng As/ml; packed cells, range: 2.1-68.4 ng As/g, median: 9.5 ng As/g; versus range: 0.51-14.44 ng As/g, median: 3.17 ng As/g). Arsenic concentrations remained unaltered, before versus after a single hemodialysis treatment. The arsenic contents of serum and packed cells were significantly correlated (n = 7, r = 0.96, p < 0.05). No arsenic could be detected in the heparin solution or in the dialysate.

Aged↗
PubMed1992

A case of Omenn-like immunodeficiency syndrome.

We report the case of a child with a variant of the Omenn immunodeficiency syndrome. He presented with erythroderma, lymphadenopathy, hepatosplenomegaly, failure to thrive, and recurrent purulent infections. The immunological studies showed marked disturbances in the subpopulations and functions of T lymphocytes, which suggests a defect in T cell differentiation as the cause of the disease.

Humans↗