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Biomedical subjects

S Lauwers

Publications and source records attributed to S Lauwers.

At least 37 records · Page 2Linked to original sources
PubMed1998

Development of an enterovirus specific PCR method for the quantification of enterovirus genomes in blood of diabetes patients.

BACKGROUND: Insulin-dependent diabetes mellitus or type 1 diabetes is a disease with a diverse aetiology. Epidemiological studies examining newly diagnosed, recent onset IDDM patients have suggested a role for viruses in the aetiology of IDDM (Yoon, 1995, Diabetes/Metabolism Reviews 11, 83-107). Important candidates are the enteroviruses, in particular coxsackieviruses B3 and B4. The latter can cause diabetes in animals (Clements et al., 1995, Lancet 346, 221-223). OBJECTIVES: We have developed a quantitative PCR method for the detection of enterovirus genomes in biological samples. The quantitative PCR will be used to screen for enteroviruses in blood of diabetes patients and their relatives by testing a Blood Diabetes Register. STUDY DESIGN: A substantial amount of data has been collected on enterovirus induced IDDM, our study is original in so far as it will be: (1) a quantitative study, not only the presence of viral genome sequences in blood will be determined, but also their concentrations (viral load); and (2) a longitudinal study, samples are and will be collected as a function of time. Positive PCR samples will be quantified using the standard addition method. RESULTS: The test is specific for enteroviruses, since all enteroviruses were detected with equal sensitivity. Viruses belonging to other picornavirus genera scored negative (even up to 3 x 10(6) genome copies). An equal detection limit of 10 genome copies was found for all enteroviruses. CONCLUSIONS: The developed method will permit us to generate quantitative and longitudinal data of enterovirus genomes in blood of diabetes patients and their relatives, which might help in the elucidation of the relationship between enteroviruses and IDDM.

Diabetes Mellitus, Type 1↗
PubMed1998

Surgical site infections.

The New CDC-definitions for surveillance of surgical site infections (1992) take into account 3 classes of surgical site infections (SSI): superficial and deep incisional SSI, and organ/space SSI. The most important host-related risk factors for development of SSI are advanced age, morbid obesity, disease severity, an ASA score > 2, prolonged preoperative hospital stay, and infection at distal sites. Microbial contamination of the surgical site occurs mainly during the surgical intervention. Although exogenous contamination may be of concern, especially in clean operations, most surgical site infections are caused by microorganisms of the patient's own commensal flora. SSI rates vary according to the type and duration of the surgical procedure and the skill of the surgeon. Proper surgical technique is the most important factor in the prevention of SSI. Modification of host risk factors should be attempted whenever possible. In addition, adequate protocols for antimicrobial prophylaxis with antibiotics should be followed. Surveillance of surgical site infections is probably beneficial for SSI prevention.

Age Factors↗
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

Comparative in-vitro activity of cefpirome against isolates from intensive care and haematology/oncology units. Belgian Multicentre Study Group.

The susceptibility of 389 Enterobacteriaceae, 231 other Gram-negative bacilli (including 150 Pseudomonas aeruginosa) and 233 Gram-positive organisms was determined by the NCCLS reference microdilution technique against cefpirome and other antibiotics. Cefpirome and cefepime were the most active compounds against Enterobacteriaceae, including potentially beta-lactamase-inducible species. The MIC90 of cefpirome against potentially inducible and non-inducible species of Enterobacteriaceae was 2 mg/L and 0.5 mg/L, respectively. Ceftazidime, cefpirome and cefepime had similar activity against P. aeruginosa, with MIC90s of 64 mg/L, 64 mg/L and 32 mg/L, respectively. Cefpirome and cefepime had similar activity against Gram-positive cocci, with MIC90s of 1 mg/L and 2 mg/L, respectively, against oxacillin-susceptible Staphylococcus aureus and 64 mg/L and 128 mg/L, respectively, against Enterococcus spp.; both had an MIC90 of 1 mg/L against Streptococcus pneumoniae. This study shows that fourth-generation cephalosporins, such as cefpirome, could be useful in haematology/oncology units and, in particular, ICUs where high resistance rates are observed.

Cefepime↗
PubMed1998

Identification of new verocytotoxin type 2 variant B-subunit genes in human and animal Escherichia coli isolates.

The sequence of a verocytotoxin 2 (VT2) variant gene that was untypeable by the B subunit PCR and restriction fragment length polymorphism analysis (PCR-RFLP) method described by Tyler et al. (S. D. Tyler, W. M. Johnson, H. Lior, G. Wang, and K. R. Rozee, J. Clin. Microbiol. 29:1339-1343, 1991) was determined and compared with published sequences. It was highly homologous to two recently reported VT2 variant sequences. The PCR-RFLP method described by Tyler et al. was extended to include these new sequences. New VT2 variants were identified in 65 of 359 VT-producing Escherichia coli (VTEC) with newly designed primers (VT2-cm and VT2-f) and were characterized as well by restriction analysis of the amplification products obtained with another VT2-specific primer pair (VT2-e and VT2-f). The VT genes harbored by 64 of these isolates proved to be untypeable by Tyler's PCR-RFLP method because no amplification was obtained with the primers used with this method (VT2-c and VT2-d). The last isolate harbored the new variant gene in addition to VT2vh-a. None of the isolates harboring these new toxin genes belonged to serogroups O157, O26, O103, O111, and O145. All 65 isolates were negative for the eaeA gene and were significantly less frequently enterohemolytic or positive for the enterohemorrhagic E. coli (EHEC) virulence plasmid than non-O157 VTEC isolates harboring other VT2 genes. They were also less frequently isolated from patients with EHEC-associated symptoms. The extended PCR-RFLP typing method is a useful tool to identify less-virulent VTEC isolates and for VT genotyping in epidemiological studies with non-O157 strains.

Animals↗
PubMed1998

Development of a monoclonal antibody to a Ureaplasma urealyticum serotype 9 antigen.

We produced a monoclonal antibody (MAb) to Ureaplasma urealyticum Vancouver, the serotype 9 standard strain. By immunoblotting, this MAb showed a single, 85-kDa band with the homologous serotype and a minor, 100-kDa band with serotype 2 but did not react with any other serotype standard strain. Clinical isolates of U. urealyticum were tested with this MAb and with two sets of polyclonal antisera against the 14 serotype standard strains. The use of MAb 9-2H9 correctly identified certain serotype 9 strains but did not react with wild-type strains lacking the serotype 9 determinant.

Animals↗
PubMed1997

Severe community-acquired pneumonia caused by atypical organisms.

Three cases of community-acquired pneumonia (CAP), requiring intensive care admission, are presented. The clinical picture of a "typical" bacterial pneumonia in the three patients led to an initial empirical treatment with amoxicillin clavulanic acid or 2(nd) generation cephalosporins. The treatment had to be changed in all three because of clinical failure. Erythromycin was added to the therapy with good clinical evolution. Serology confirmed atypical organisms to be responsible. Only the chest X-ray might have suggested an "atypical" or a "viral-like" agent. A proposition is made for an empirical combination of antibiotics in severely ill patients with CAP with more than unilobar consolidation.

Adult↗
PubMed1997

Occurrence of multiple genomovars of Burkholderia cepacia in cystic fibrosis patients and proposal of Burkholderia multivorans sp. nov.

We performed an integrated genotypic and phenotypic analysis of 128 strains of the genera Burkholderia, Ralstonia, and Pseudomonas in order to study the taxonomic structure of Burkholderia cepacia and its relationships with other Burkholderia species. Our data show that presumed B. cepacia strains isolated from cystic fibrosis patients belong to at least five distinct genomic species, one of which was identified as Burkholderia vietnamiensis. This group of five phenotypically similar species is referred to as the B. cepacia complex. The name Burkholderia multivorans is proposed for one of these genomic species, which was formerly referred to as B. cepacia genomovar II; the remaining B. cepacia groups are referred to as genomovars I, III, and IV, pending additional differential phenotypic tests. The role and pathogenic potential of each of these taxa, particularly in view of the potentially fatal infections in cystic fibrosis patients, need further evaluation. The data presented also demonstrate that Pseudomonas glathei and Pseudomonas pyrrocinia should be reclassified as Burkholderia species.

Bacterial Proteins↗
PubMed1997

Virulence factors of verocytotoxin-producing Escherichia coli isolated from raw meats.

PCR for verocytotoxin-producing Escherichia coli (VTEC) was positive in 4.6% of 2,440 raw meat samples; only beef, sheep, and venison samples were positive. None of the isolated VTEC strains belonged to serogroup O157. Additional virulence factors were detected in only a minority of strains, suggesting that most of these meat VTEC isolates are not pathogenic.

Animals↗
PubMed1996

Isolation of HIV-1 RNA from plasma: evaluation of eight different extraction methods.

The efficacy of eight different methods for the extraction of HIV-1 RNA from plasma was compared. The RNA preparation method that gave the best results by RT-PCR was the one described by Chomczynski and Sacchi (1987, Anal. Biochem. 162, 156-159). This method consists of a guanidine thiocyanate treatment followed by three phenol-chloroform-isoamylalcohol extractions and an ethanol precipitation. The disadvantage of this method is that it is time consuming and less suitable for the extraction of large series of samples. Moreover, due to the large number of procedural steps, there is a greater risk of sample mix-up or contamination. Of the single-step RNA purification methods, good results were obtained with the TRIzol method (Gibco Life Technologies, Paisley, UK) and with the extraction method offered by the NASBA kit (Organon Teknika, Turnhout, Belgium). The above single-step methods are recommended since both are sensitive enough to detect low copy numbers of HIV-RNA in the plasma of asymptomatic patients, and require only 2 h for completion. For most of the methods evaluated the inter-test variability was acceptable (mean variation coefficient between duplicate extraction varied between 17.3 and 47.3%). Inter-laboratory reproducibility was evaluated only for the TRIzol-method and found to be low (mean variation coefficient 63.4).

Evaluation Studies as Topic↗
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

Burkholderia (Pseudomonas) cepacia and cystic fibrosis: the epidemiology in Belgium.

Burkholderia cepacia has become an increasingly recognized pathogen among cystic fibrosis (CF) patients and its potential role in declining pulmonary function or unexpected fatal outcome has caused widespread concern. Direct person-to-person transmission has been documented and a segregation policy of CF patients colonized with B.cepacia from non-colonized CF patients is widely adopted. Since this policy has a dramatic impact on social behaviour of CF patients it is imperative that clinical laboratories accurately isolate and identify B.cepacia in the respiratory secretions. In order to comprehend the epidemiology of B.cepacia in the Belgian CF population a multicentre study was conducted during a period of 1 year (March'93-February'94). B.cepacia was isolated in only 12 of 465 CF patients (2.6%). Routine biochemical tests identified these strains as authentic B.cepacia. However, the combined data from protein and DNA-DNA hybridization analyses revealed that the Belgian CF "B.cepacia" isolates showed patterns different from reference B.cepacia isolates and belong to 3 different, newly identified Burkholderia genomovars, but not to B.cepacia. Comparative analysis of the selective media used for recovery of these "B.cepacia" strains from respiratory secretions indicated that the commercial medium (Mast) containing polymyxin B and ticarcillin as the selective agents was the best and most user-friendly. Molecular typing of these Burkholderia isolates by arbitrarily-primed PCR (AP-PCR) and pulsed-field gel electrophoresis (PFGE) showed that spread of a single strain within a same centre occurred but the mode of transmission remains unknown; inter-centre spread of strains was not observed. Interestingly, neither colonization with a distinct or an epidemic strain (belonging to either of the three newly identified Burkholderia genomovars) nor colonization for a prolonged period of time, led to a rapid deterioration of lung function in these CF patients. It appears essential to determine the prevalence of these "new" Burkholderia genomovars in larger populations of CF patients and to evaluate their virulence and other features as this may have important clinical and practical implications.

Adolescent↗
PubMed1996

Acidification of methyl-alpha-D-glucopyranoside: a useful test to differentiate Enterococcus casseliflavus and Enterococcus gallinarum from Enterococcus faecium species group and from Enterococcus faecalis.

Enterococcus gallinarum and E. casseliflavus are difficult to differentiate from other enterococci, particularly E.faecium. The former two species were found to produce acid from methyl-alpha-D-glucopyranoside in phenol red broth, while E.faecalis strains and strains of the E.faecium species group, including E.faecium, E.durans, E. hirae, and E.mundtii, failed to produce acid from this substrate.

Bacterial Typing Techniques↗