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Biomedical subjects

L Verbist

Publications and source records attributed to L Verbist.

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

In-vitro activities of 16 non-beta-lactam antibiotics against penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae.

MICs of 16 non-beta-lactams were determined by agar dilution for 283 penicillin-susceptible, 122 intermediate and 23 fully penicillin-resistant isolates of pneumococci. Penicillin-resistant pneumococci were more likely to be resistant to tetracyclines, macrolides and related compounds. In the latter group, quinupristin/dalfopristin was the only compound whose activity was not influenced by penicillin resistance. Among the fluoroquinolones, clinafloxacin and trovafloxacin showed excellent activity. Strains resistant to macrolides, tetracycline and penicillin were concentrated in serogroups 6, 9, 14, 19 and 23.

Anti-Bacterial Agents↗
PubMed1998

Interaction of interstitial trophoblast with placental bed capillaries and venules of normotensive and pre-eclamptic pregnancies.

While endovascular trophoblast invasion of the human placental bed spiral arteries has been studied extensively, no information is available on the interaction between interstitially invading trophoblast and uterine capillaries and venules. Placental bed biopsies of eight normotensive and 15 pre-eclamptic patients were double-immunostained for cytokeratin and the endothelial marker CD31, providing satisfactory staining results in six and 10 biopsies, respectively. Interstitial trophoblast tissue density did not differ between the two series of biopsies, implying that this pathway of invasion is not impaired in pre-eclampsia. Both groups showed a similar incidence of approach of non-arterial vascular structures by perivascular trophoblast. Differences in CD31 staining intensity were noticed in different vascular cross-sections. Lower staining intensity was related to the presence of perivascular trophoblast. Because of the identity of CD31 with the platelet-endothelial cell adhesion molecule (PECAM)-1, the trophoblast-dependent downregulation of CD31 may play a role in the control of leukocytic traffic within the placental bed. The phenomena described in this paper did not show any difference between the normotensive and pre-eclamptic patients, implying that interaction of interstitial trophoblast with venous and capillary structures is not related to the pathogenesis of pre-eclampsia.

Adult↗
PubMed1998

Renin-like immunoreactivity in uterus and placenta from normotensive and hypertensive pregnancies.

OBJECTIVES: (1) To identify the distribution of renin-like immunoreactivity in placental bed, placenta-free uterine wall, placenta, fetal membranes, and intertwin membranes obtained from normal pregnancies and (2) to compare the findings in normal pregnancies with those in pregnancies complicated by various hypertensive disorders. STUDY DESIGN: Biopsies were taken from 31 normotensive pregnant women, eight of whom had twin pregnancies, and from 28 women with various hypertensive disorders of pregnancy. The anti-human renal renin monoclonal antibody, F37.1A1, was used for immunostaining. Histological structures were identified with standard H&E and PAS techniques, supplemented with immunostaining using the specific cell markers CD68 and cytokeratin. RESULTS: Renin-like immunoreactivity was found in cytokeratin immunolabelled placental syncytiotrophoblast, amnionic and glandular epithelium, but most consistently in CD68 immunolabelled maternal and fetal macrophages. The distribution of renin-like immunoreactivity throughout the pregnant uterus roughly parallelled reported renin concentrations in the various tissues, while its localization conforms also with that of cathepsin D. There were no obvious differences in renin-like immunolabelling between normotensive or hypertensive women. Renin-like immunoreactivity was particularly common in the atherotic lesions that are observed more often in pregnancies complicated with hypertensive disorders of pregnancy and/or intra-uterine growth restriction. CONCLUSIONS: The data complement earlier findings showing that only two of four anti-renal renin monoclonal antibodies, both of which cross-react with cathepsin D, give a positive immunostaining in placental tissue. They question whether classical concepts on renin localisation in uteroplacental tissues all relate to one and the same enzyme. The demonstration of renin-like enzymes in different cell types, including macrophages, may explain the diversity of functions that has been attributed to uterine renin. There were no differences between tissues obtained from normotensive and hypertensive pregnancies, except for the consistent presence of renin-like immunoreactivity in atherotic lesions.

Antigens, CD↗
PubMed1998

Prospective study of catalase-positive coryneform organisms in clinical specimens: identification, clinical relevance, and antibiotic susceptibility.

During a 6-month period, all clinical isolates of catalase-positive coryneform organisms, which were isolated during the routine processing of clinical specimens, were characterized in the laboratory of the 1800-bed University Hospital of Leuven. The distribution of the species in the corynebacteria was: Corynebacterium amycolatum 70 (53%), Corynebacterium jeikeium 16 (12%), Corynebacterium striatum 11 (8%), Corynebacterium afermentans 10 (7%), Corynebacterium minutissimum 9 (6%), CDC coryneform group G 4 (3%), Corynebacterium urealyticum 4 (3%), Corynebacterium glucuronolyticum 1 (0.7%), and Corynebacterium xerosis 1 (0.7%). Of the 150 isolates, 37 (25%) were considered to be infection related and the remaining 113 (75%) were of questionable clinical significance. Susceptibility of the corynebacteria to 12 antibiotics active against Gram-positive organisms was evaluated. C. amycolatum, C. jeikeium, and C. urealyticum were multiresistant, but all isolates were susceptible to teicoplanin and vancomycin. Most of the C. amycolatum strains, and all strains of C. jeikeium and C. striatum, were susceptible to the vibrocidal compound O/129.

Actinomycetales↗
PubMed1998

Surveillance of human Yersinia enterocolitica infections in Belgium: 1967-1996.

Between 1967 and 1996, > 18,700 strains of Yersinia species, excluding Yersinia pestis, were recovered in Belgium from a variety of gastrointestinal and extraintestinal sites in patients. Full identification and serotyping were performed by the two Belgian reference laboratories. Yersinia enterocolitica serogroup O:3 predominated (79.4% of strains), followed by serogroup O:9 (11.1%). The remaining 9.5% of isolates belonged to serogroups and related species generally considered nonpathogenic. Acute enterocolitis was the most common clinical form of Y. enterocolitica infection, affecting primarily children younger than 5 years of age. Since 1967, there was a steady increase in isolations every year, with 305 cases in 1975 and up to 1,469 in 1986. From 1987 on, there was a clear decrease in the number of reported cases, although the number of participating laboratories and culture techniques remained constant. This significant decrease in the occurrence of Y. enterocolitica infections may be explained by changes in the slaughtering procedures and eating habits of the population.

Adolescent↗
PubMed1998

Surgical prophylaxis in Belgian hospitals: estimate of costs and potential savings.

Between 1991 and 1995 the Belgian National Program for Surveillance of Hospital Infections (NSIH) collected data on perioperative antibiotic prophylaxis in 72 acute care hospitals. From the costs of prophylactic antibiotics for six categories of surgical procedure and from discharge summaries for hospitalization episodes nationwide, annual drug costs were estimated for 73% of Belgian surgical activity. Costs of antibiotics used in these surgical activities were estimated at 386-410 million Belgian francs (Bf) per year (US$12.1-12.9 million). After agreeing recommendations for best practice, the hypothetical costs of 'optimal' antimicrobial prophylaxis were calculated for the same selection of surgical procedures. It was calculated that savings of at least 194 million Bf (US$6.1 million) could be made if recommendations were followed closely. Only the costs borne by the National Health Insurance Institute for reimbursement of the dispensed drugs were considered in this study. Other direct costs, such as those related to drug storage, dispensing and administration, were not included.

Anti-Bacterial Agents↗
PubMed1998

In-vitro activity of 21 beta-lactam antibiotics against penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae.

MICs of 21 beta-lactams were determined by agar dilution against 283 penicillin-susceptible (pen-S), 122 intermediate (pen-I) and 23 fully penicillin-resistant (pen-R) pneumococci. MICs of all beta-lactams increased with increasing MICs of penicillin. Clometocillin was the most active penicillin against pen-I or pen-R pneumococci. All oral cephalosporins except cefuroxime and cefpodoxime were less active than penicillin and none was satisfactory against pen-I or pen-R pneumococci. The parenteral third- and fourth-generation cephalosporins (except ceftazidime) were similar in activity to penicillin against pen-S isolates. Cefpirome showed the lowest mean MICs against pen-I and pen-R strains.

Amoxicillin↗
PubMed1998

Disappointing dipstick screening for urinary tract infection in hospital inpatients.

AIM: To compare the performance of leucocyte esterase and nitrite dipstick tests with microscopic examination and culture of first morning urines (n = 420) of hospital inpatients. RESULTS: The sensitivity, specificity, and negative predictive value of the leucocyte esterase test for the cutoff of > 10 WBC/microliter were 57%, 94%, and 68%, respectively. For > 5 WBC per high power field (HPF) these variables were 84%, 90%, and 93%. For > 10(5) colony counts/ml, the sensitivity of the nitrite test was 27%, specificity 94%, and negative predictive value 87%. When either leucocyte esterase or nitrite positivity was accepted as a marker of urinary tract infection, the sensitivity was 78%, specificity 75%, and negative predictive value 94%, and there were 22% false negative results. Semiquantitative microscopic estimation of bacteria per HPF yielded 40% false positives. CONCLUSIONS: Leucocyte esterase and nitrite dipstick tests are not suitable for screening for urinary tract infections.

Adolescent↗
PubMed1997

Randomized, controlled trial of selective digestive decontamination in 600 mechanically ventilated patients in a multidisciplinary intensive care unit.

OBJECTIVE: To evaluate the efficacy of two regimens of selective decontamination of the digestive tract in mechanically ventilated patients. DESIGN: Prospective, randomized, concurrent trial. SETTING: Multidisciplinary intensive care unit (ICU) in a 1,800-bed university hospital. PATIENTS: Consecutive patients (n = 660) who were likely to require mechanical ventilation for at least 48 hrs were randomized to one of three groups: conventional antibiotic regimen (control group A); oral and enteral ofloxacin-amphotericin B (group B); and oral and enteral polymyxin E-tobramycin-amphotericin B (group C). Both treatment groups received systemic antibiotics for 4 days (ofloxacin in group B and cefotaxime in group C). INTERVENTIONS: Patients were randomized to receive standard treatment (control group A, n = 220), selective decontamination regimen B (group B, n = 220), and selective decontamination regimen C (group C, n = 220). After early deaths and exclusions from the study, 185 controls (group A) and 193 (group B)/200 (group C) selective decontamination regimen patients were available for analysis. MEASUREMENTS AND MAIN RESULTS: Measurements included colonization and primary/secondary infection rate, ICU mortality rate, emergence of antibiotic resistance, length of ICU stay, and antimicrobial agent costs. The study duration was 19 months. The patient groups were fully comparable for age, diagnostic category, and severity of illness. One third of patients in each group suffered a nosocomial infection at the time of admission. There was a significant difference between treatment group B and control group A in the number of infected patients (odds ratio of 0.42, 95% confidence interval of 0.27 to 0.64), secondary lower respiratory tract infection (odds ratio of 0.47, 95% confidence interval of 0.26 to 0.82), and urinary tract infection (odds ratio of 0.47, 95% confidence interval of 0.27 to 0.81). Significantly more Gram-positive bacteremias occurred in treatment group C vs. group A (odds ratio of 1.22, 95% confidence interval 0.72 to 2.08). Infection at the time of admission proved to be the most significant risk factor for subsequent infection in control and both treatment groups. ICU mortality rate was almost identical (group A 16.8%, group B 17.6%, and group C 15.5%) and was not significantly related to primary or secondary infection. Increased antimicrobial resistance was recorded in both treatment groups: tobramycin-resistant enterobacteriaceae (group C 48% vs. group A 14%, p < .01), ofloxacin-resistant enterobacteriaceae (group B 50% vs. group A 11%, p < .02), ofloxacin-resistant nonfermenters (group B 81% vs. group A 52%, p < .02), and methicillin-resistant Staphylococcus aureus (group C 83% vs. group A 55%, p < .05). Antimicrobial agent costs were comparable in control and group C patients; one third less was spent for group B patients. CONCLUSIONS: In cases of high colonization and infection rates at the time of ICU admission, the preventive benefit of selective decontamination is highly debatable. Emergence of multiple antibiotic-resistant microorganisms creates a clinical problem and a definite change in the ecology of environmental, colonizing, and infecting bacteria. The selection of multiple antibiotic-resistant Gram-positive cocci is particularly hazardous. No beneficial effect on survival is observed. Moreover, selective decontamination adds substantially to the cost of ICU care.

Adult↗
PubMed1996

In vitro activity of trovafloxacin versus ciprofloxacin against clinical isolates.

The comparative in vitro activity of trovafloxacin (CP 99,219), a new fluoroquinolone, was evaluated against 511 clinical isolates. MICs of trovafloxacin were fourfold higher than those of ciprofloxacin for 184 Enterobacteriaceae and 110 non-fermentative gram-negative bacilli. However, trovafloxacin was 16-fold more active than ciprofloxacin against 162 gram-positive staphylococci, pneumococci, streptococci, and enterococci, and two- to fourfold more active against Haemophilus influenzae and Moraxella catarrhalis. MICs of trovafloxacin were correspondingly higher for strains with acquired resistance to ciprofloxacin.

Anti-Infective Agents↗
PubMed1996

In vitro activity of amoxycillin/clavulanate and ticarcillin/clavulanate compared with that of other antibiotics against anaerobic bacteria: comparison with the results of the 1987 survey.

The activity of amoxycillin/clavulanate (Augmentin) and ticarcillin/ clavulanate (Timentin) was tested against 351 strict anaerobic clinical isolates collected from September 1993 to April 1994 in eight Belgian university hospitals and compared with that of 8 other antibiotics using the NCCLS reference agar dilution procedure. Production of beta-lactamase was detected by the nitrocefin test in 48% of the isolates. At NCCLS-recommended breakpoints, more than 90% of isolates were susceptible to amoxycillin/clavulanate, ticarcillin/clavulanate, piperacillin/tazobactam, imipenem, chloramphenicol and metronidazole but only 77%, 72% and 48% to cefoxitin, clindamycin and penicillin, respectively. In comparison with the results of a similar survey conducted in 1987 no major changes in susceptibility were observed except for the susceptibility to clindamycin that declined from 83% to 72% overall, and from 83% to 66% in the B. fragilis group. Furthermore one isolate of Clostridium clostridioforme was found produce beta-lactamase and few B. fragilis group isolates showed reduced susceptibility to metronidazole.

Amoxicillin↗
PubMed1996

Bacteraemia with Leptotrichia buccalis: report of a case and review of the literature.

We report here on a new case of L. buccalis bacteraemia. To our knowledge 16 other cases of L. buccalis bacteraemia have been reported in the literature, most of them in neutropenic patients. However L buccalis endocarditis does occasionally occur in non-neutropenic patients. The identification of L. buccalis is based on well known phenotypic features and confirmed by the detection of a large peak of lactic acid by gas chromatography for non volatile organic acids. L. buccalis is sensitive to a wide range of antibiotics including beta-lactam antibiotics, but it is resistant to aminoglycosides and macrolides.

Aged↗
PubMed1996

Comparative activity of piperacillin/tazobactam against 5625 isolates from hospitalised patients. Multicentre Study Group.

The comparative activities of piperacillin/tazobactam and other antibiotics against 5625 Gram-negative and Gram-positive bacteria freshly isolated from hospitalized patients was examined. The percentage of Enterobacteriaceae susceptible to piperacillin/tazobactam, ceftazidime, imipenem and ciprofloxacin was very similar and varied from 81% to 84% in the Enterobacteriaceae with inducible type 1 beta-lactamases and from 93 to 97% in the non-inducible organisms. Piperacillin/tazobactam was similar in activity to ceftazidime against Pseudomonas aeruginosa and more active than imipenem or ciprofloxacin. Piperacillin/tazobactam is more active than ceftazidime against Gram-positive bacteria (staphylococci, enterococci) and seems to be a promising antibiotic for nosocomial infections.

Bacteria↗
PubMed1996

Prospective clinical evaluation of Amplicor Mycobacterium tuberculosis PCR test as a screening method in a low-prevalence population.

Of 656 respiratory samples analyzed for Mycobacterium tuberculosis by microscopy, culture, and the Amplicor PCR method, 25 were positive by culture, 12 were positive by microscopy, and 17 were positive by the Amplicor PCR method; 16 samples were Amplicor PCR positive and culture negative. No patient except one with culture-negative, Amplicor PCR-positive samples had clinical indications of tuberculosis. The sensitivity and specificity of the Amplicor PCR compared with those of culture were 68 and 97.4%, respectively. For culture-positive, smear-negative samples, the sensitivity of the Amplicor PCR was 46%.

Adult↗
PubMed1996

Belgian multicentre study on the in vitro activity of cefepime against gram-negative bacilli.

The in vitro activity of cefepime has been compared with that of cefotaxime, ceftazidime, aztreonam, and piperacillin against 1826 Enterobacteriaceae including 537 inducible Enterobacteriaceae (Enterobacter spp., Serratia spp., Citrobacter spp,. Morganella morganii) and 572 non-fermenters, including 401 Pseudomonas aeruginosa and 111 Acinebacter spp. isolated from hospitalized patients in 28 Belgian hospitals. Overall, cefepime was found substantially more active than the third-generation cephalosporins, aztreonam and piperacillin against Enterobacteriaceae species producing inducible type I cephalosporinases. Notably, cefepime remained active against 96% of Enterobacteriaceae resistant to cefotaxime, ceftazidime or aztreonam while it displayed a similar activity against E. coli and the other Enterobacteriaceae. Against non-fermenters, cefepime was found less active than ceftazidime but more than cefotaxime or aztreonam.

Anti-Bacterial Agents↗