PubMed Health⌕ Search

Biomedical subjects

M J Struelens

Publications and source records attributed to M J Struelens.

At least 19 recordsLinked to original sources
PubMed2006

Validation of pulsed-field gel electrophoresis and spa typing for long-term, nationwide epidemiological surveillance studies of Staphylococcus aureus infections.

Pulsed-field gel electrophoresis (PFGE) of genomic macrorestriction fragments has been used by the Belgian Reference Laboratory for Staphylococci for national hospital surveys of methicillin-resistant Staphylococcus aureus since 1992. The sequencing of the polymorphic X region of the protein A gene (spa typing) offers significant advantages over PFGE in terms of speed, ease of interpretation, and exportability. To validate its potential use for national surveillance, we evaluated the robustness of spa typing compared with that of PFGE based on a collection of 217 S. aureus strains representative of the Belgian S. aureus epidemiology during the last 13 years. spa typing and PFGE both showed high discriminatory power (discriminatory indexes of 0.98 and 0.96, respectively) and achieved high concordance (95.9%) in type classification. Both methods also showed good concordance with multilocus sequence typing (MLST) (95.5%). However, we observed occasional "violations" of MLST clonal complex assignment by spa typing. Our results suggest that both PFGE and spa typing are reliable methods for long-term, nationwide epidemiological surveillance studies. We suggest that spa typing, which is a single-locus-based method, should preferably be used in combination with additional markers, such as staphylococcal cassette chromosome mec typing or resistance or virulence gene detection.

Anti-Bacterial Agents↗
PubMed2006

Status of infection control policies and organisation in European hospitals, 2001: the ARPAC study.

Patient safety in hospital care depends on effective infection control (IC) programmes. The Antimicrobial Resistance Prevention and Control (ARPAC) study assessed the organisation, components and human resources of IC programmes in European hospitals. A questionnaire survey of policies and procedures implemented in 2001 for the surveillance and control of nosocomial infection and antibiotic resistance was completed by 169 acute-care hospitals from 32 European countries, categorised by five geographical regions. A formal IC programme existed in 72% of hospitals, and a multidisciplinary IC committee was operational in 90%. Trained IC nurses (ICNs) were present in 80% of hospitals (ranging from 54% in south-east and central-eastern Europe, to 100% in northern Europe), whereas 74% had one or more trained IC doctors (ICDs) (ranging from 46% in south-east Europe to 84% in western Europe). Median staffing levels were 2.33 ICNs/1,000 beds and 0.94 ICDs/1,000 beds. The intensity of IC programmes scored higher in centres from northern and western Europe than from other European regions. Written guidelines promoted hand hygiene for healthcare workers in 89% of hospitals, education in 85%, and audit in 46%. Guidelines recommended use of alcohol-based solutions (70%) and/or medicated/antiseptic soap (43%) for decontamination of non-soiled hands. Use of alcohol-based solutions varied according to region, from 41% in southern Europe to 100% in northern Europe, compared with use of medicated soap from 77% in southern Europe to 11% in northern Europe (p < 0.01). These findings showed that IC programmes in European hospitals suffer from major deficiencies in human resources and policies. Staffing levels for ICNs were below recommended standards in the majority of hospitals. Education programmes were incomplete and often not supported by audit of performance. Hand hygiene procedures were sub-standard in one-third of centres. Strengthening of IC policies in European hospitals should be a public health priority.

Cross Infection↗
PubMed2006

External quality assessment of molecular typing of Staphylococcus aureus isolates by a network of laboratories.

A network of laboratories designated Centres for Molecular Diagnosis was funded in 2000 by Belgian National Health Insurance to provide clinically relevant molecular diagnostic tests. These included typing of nosocomial pathogens as a service to local hospital infection control programs. Two external quality assessment (EQA) surveys were performed in 2001 and 2003 to evaluate the proficiencies of the laboratories at Staphylococcus aureus typing. EQA panels included S. aureus isolates with either indistinguishable, clonally related, or unrelated pulsed-field gel electrophoresis (PFGE) patterns. A hypothetical hospital outbreak problem was also submitted for analysis. Typeability, reproducibility, discrimination (D) index, and epidemiological concordance were evaluated. Ten centers participated in each survey. Seven centers performed PFGE analysis, while others used repetitive-element or randomly amplified polymorphic DNA PCR, amplified fragment length polymorphism, or spa typing. Full typeability (100%) was achieved by all centers, and all but one showed 100% reproducibility. Discrimination was appropriate (D index, >or=96%) for centers performing PFGE analysis but not for all those using other methods (D index range, 72% to 97%). Correct answers to the epidemiological questions were provided by 7/10 and 10/10 centers in 2001 and 2003, respectively. Individual feedback of results was provided to each center together with specific technical recommendations for improving performance. Our findings indicate that surveys of lab proficiency are useful for validation and optimization of molecular typing services to local hospital infection control programs.

Bacterial Typing Techniques↗
PubMed2006

High interlaboratory reproducibility of DNA sequence-based typing of bacteria in a multicenter study.

Current DNA amplification-based typing methods for bacterial pathogens often lack interlaboratory reproducibility. In this international study, DNA sequence-based typing of the Staphylococcus aureus protein A gene (spa, 110 to 422 bp) showed 100% intra- and interlaboratory reproducibility without extensive harmonization of protocols for 30 blind-coded S. aureus DNA samples sent to 10 laboratories. Specialized software for automated sequence analysis ensured a common typing nomenclature.

Bacterial Typing Techniques↗
PubMed2005

Polyclonal emergence and importation of community-acquired methicillin-resistant Staphylococcus aureus strains harbouring Panton-Valentine leucocidin genes in Belgium.

OBJECTIVES: Worldwide spread of a limited number of Panton-Valentine leucocidin (PVL) -producing methicillin-resistant Staphylococcus aureus (MRSA) clones has been reported in various communities. The objective of this study was to describe the molecular characteristics of the first PVL-positive MRSA strains isolated in Belgium. METHODS: Clinical MRSA isolates (n = 41) collected from 2002 to 2004 from Belgian patients were investigated for the PVL gene by PCR. PVL-positive isolates were genotyped by PFGE, staphylococcal cassette chromosome mec (SCCmec) typing, spa sequence typing, accessory gene regulator (agr) polymorphism and multi-locus sequence typing (MLST). Susceptibility to 14 antimicrobials was determined by the disc diffusion method. Genes encoding resistance to tetracyclines, aminoglycosides and macrolide-lincosamide-streptogramin were determined by PCR. RESULTS: Sixteen isolates carried lukS-lukF genes that encode the PVL toxin. All but one isolate were community-acquired. Three patients reported recent travel to North Africa and South America. They were associated with skin or soft tissue infections, bacteraemia and peritonitis. By molecular typing, they belonged to five genotypes: ST80-SCCmec IV, ST8-SCCmec IV, ST30-SCCmec IV, ST153-SCCmec IV and ST88-SCCmec IV. They belonged to the agr type 3 except for ST8 strains, which showed agr type 1. All isolates were susceptible to fluoroquinolones. Approximately, half of them were resistant to tetracycline, fusidic acid and kanamycin. Tetracycline-resistant strains harboured the tet(K) gene and resistance to kanamycin was associated with the aph3'-IIIa gene. The single erythromycin-resistant isolate harboured msr(A/B) genes conferring the M resistance phenotype. CONCLUSIONS: These results indicate the recent emergence and sporadic importation into Belgium of PVL-positive community-associated MRSA strains belonging to five distinct clones.

Adolescent↗
PubMed2005

Evaluation of the Vitek 2 system for identification and antimicrobial susceptibility testing of Staphylococcus spp.

The Vitek 2 system was assessed against reference methods with 197 methicillin-resistant Staphylococcus aureus from Belgian hospitals and 121 clinically significant blood culture isolates of Staphylococcus spp. Vitek 2 identified 95% of staphylococcal isolates correctly, detected oxacillin resistance with a sensitivity/specificity of 99/96%, and showed acceptable accuracy for susceptibility testing of five of eight other evaluable antibiotics. The median time for reporting results was 2 h 45 min for identification and 7 h for susceptibility tests.

Methicillin Resistance↗
PubMed2005

Low prevalence of methicillin-resistant Staphylococcus aureus with reduced susceptibility to glycopeptides in Belgian hospitals.

Staphylococcus aureus strains with decreased susceptibility to glycopeptides (GISA) have been associated with increased risk of glycopeptide treatment failure. To assess the prevalence of these strains in hospitalised patients in Belgium, 455 methicillin-resistant S. aureus (MRSA) isolates collected in 2001 were screened by two assays: (i) growth on vancomycin agar screen (VAS; brain heart infusion agar (BHI) + vancomycin 6 mg/L); and (ii) a synergy/antagonism test with aztreonam/cefazolin on Mu3 agar (BHI + vancomycin 3 mg/mL). Isolates growing on VAS or Mu3 agar were characterised further by analysis of population susceptibility profiles. MICs of glycopeptides were determined by agar dilution, broth microdilution and Etest (low and high inocula) methods. The isolates were genotyped by pulsed-field gel electrophoresis (PFGE) and determination of staphylococcal cassette chromosome mec (SCCmec) type. No GISA isolates were found. Three (0.7%) hetero-vancomycin intermediate S. aureus (hVISA) and ten (2.2%) hetero-teicoplanin intermediate S. aureus (hTISA) isolates were identified by population analysis. All but one hetero-GISA isolate belonged to either epidemic PFGE group A/SCCmec type I (69%) or PFGE group D/SCCmec type I (23%), both of which were resistant to gentamicin. The sensitivity and specificity for the detection of hetero-GISA by the two assays were 15.4% and 99.8%, respectively, for VAS, and 84.6% and 95.9%, respectively, for Mu3. The data indicated that hetero-GISA strains were uncommon among Belgian MRSA isolates from hospitalised patients. Use of Mu3 agar was more sensitive, but less specific, than VAS as a screening method.

Belgium↗
PubMed2005

Prevalence and risk-factors for Helicobacter pylori infection in urban and rural Beninese populations.

In total, 446 healthy individuals (240 in urban and 206 in rural environments, respectively) were selected from 96 households, based on cluster sampling of residential location. Demographic, sociological and environmental data were collected by face-to-face interviews using a standard questionnaire. Infection with Helicobacter pylori was assessed by detection of anti-H. pylori IgG serum antibodies. The prevalence of H. pylori antibodies was 75.4% in the urban population and 72.3% in rural (village) residents (p 0.459). No association was found between infection and age, gender, education level, size of household, economic activity or source of drinking water. The infection rate was higher in children whose parents were both infected, and also in children whose mother was infected (p < 0.001). By logistic regression analysis, the density of occupation of sleeping accommodation (more than three persons sharing a room; 95% odds ratio (OR) = 9.82 (4.13-23.31), p < 0.001), and the mother's status within the household (95% OR = 3.85 (1.53-9.67), p 0.003), were independent predictors for H. pylori infection. The 74% seroprevalence of H. pylori infection found in healthy Beninese individuals is similar to that reported previously from other parts of sub-Saharan Africa. Family contact with infected persons and crowded living conditions were associated with increased risk of infection. These findings are consistent with intra-familial H. pylori transmission and suggest that improvement of living conditions should be protective against infection.

Adolescent↗
PubMed2005

Report of the Consensus Conference on Antibiotic Resistance; Prevention and Control (ARPAC).

Antimicrobial resistance is a key public health concern in Europe. It is known that there are significant variations in the prevalence of resistance across Europe, and methods to reduce the problem are also assumed to vary significantly. The 'Antibiotic Resistance; Prevention and Control (ARPAC)' Concerted Action project was funded by the European Commission and conducted by four study groups of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID). The project established a network of European hospitals and collated data on antimicrobial resistance prevalence, antimicrobial susceptibility testing methods, typing methods employed, antimicrobial use, antibiotic policies and practices, and infection control policies and practices. The ARPAC Consensus Conference, entitled 'Control of antibiotic resistance in European hospitals-informing future evidence-based practice', was held in Amsterdam in November 2004. The conference was co-hosted by the European Commission, ESCMID and the Dutch Working Party on Antibiotic Policy (SWAB). Key ARPAC findings were presented and discussed in the context of the worldwide situation. The conference delivered a set of high-priority recommendations likely to have a significant impact on antimicrobial resistance. This report summarises these recommendations.

Anti-Bacterial Agents↗
PubMed2005

Molecular characterization of an epidemic clone of panantibiotic-resistant Pseudomonas aeruginosa.

We describe the molecular characterization of a multiresistant Pseudomonas aeruginosa clone causing an outbreak in the intensive care unit (ICU) of a tertiary-care university hospital. Analysis included antimicrobial susceptibility profile, O-serotyping, pulsed-field gel electrophoresis, and amplified fragment length polymorphism. Resistance mechanisms were characterized, including production of naturally occurring and acquired beta-lactamases, porin expression, and efflux pump systems. Eighteen patients were colonized or infected with multiresistant P. aeruginosa. Multiresistant P. aeruginosa was panresistant to penicillins, cephalosporins, carbapenems, aminoglycosides, and fluoroquinolones and remained susceptible only to colistin. Sixteen isolates (89%) belonged to serotype O:11, pulsed-field gel electrophoresis type A1, and amplified fragment length polymorphism type A. Resistance characterization of this epidemic clone showed an overexpression of the chromosomal cephalosporinase AmpC combined with decreased expression of porin OprD and the absence of metallo-beta-lactamase or extended-spectrum beta-lactamase. An upregulation of the MexXY efflux system due to an agrZ mutation in the mexZ repressor was detected. This epidemic clone was restricted to the ICU and was not found elsewhere in hospital. Contamination of the ICU environment and the hands of an ICU nurse with this clone suggests possible hand-borne transmission. Implementation of contact precautions effectively controlled transmission of the epidemic clone. This study illustrates the ability of multiresistant P. aeruginosa to cause an outbreak with significant morbidity and mortality and underscores the need to identify clonal outbreaks, which require targeted infection control measures.

Cross Infection↗
PubMed2004

Bacillus cereus pneumonia in a patient with acute lymphoblastic leukemia.

Reported here is a case of Bacillus cereus pneumonia that occurred in a patient with acute lymphoblastic leukemia. The presentation was severe, essentially marked by respiratory distress and pleuritic chest pain. Classic empirical treatment initiated for febrile neutropenia did not cover this rare pathogen and appropriate therapy was therefore delayed. B. cereus is most often a culture contaminant, but it can also be responsible for self-limited gastrointestinal intoxication and, more rarely, severe systemic diseases. Virulence in the case of systemic disease is attributed to tissue necrosis mediated by toxin release. B. cereus pneumonia, as described in the English-language literature, mainly affects immunocompromised patients and most often has a fatal outcome. Thus, the identification of B. cereus in clinical specimens of severely ill immunocompromised patients should lead physicians to question its clinical significance.

Adult↗
PubMed2004

Management of long-term catheter-related Brevibacterium bacteraemia.

Brevibacterium has been reported as a rare cause of implanted-device infection. In two cases of recurrent Brevibacterium casei bacteraemia associated with infection of surgically implanted intravascular devices, relapse occurred 2 and 5 months, respectively, after completion of therapy with vancomycin via the infected catheter. A second intravenous antibiotic therapy course by the antibiotic-lock technique led to bacteriological cure in one patient. Molecular typing results demonstrated that the recurrent bacteraemia was caused by the same strain. Implanted-device removal may be necessary, in addition to appropriate antibiotics, for successful management of such infections.

Actinomycetales Infections↗
PubMed2003

Haemophilus parainfluenzae: an underdiagnosed pathogen of biliary tract infections?

Presented here is a case of monobacterial peritonitis complicating cholecystitis and caused by an uncommon agent of gastrointestinal infections, Haemophilus parainfluenzae. The pathogenic role of this organism in digestive infections, particularly in those of the biliary tract, has been reported increasingly though sporadically. Indeed, it has been shown to be a coloniser of the gastrointestinal tract, and a recent hypothesis of an ascending route of infection to the biliary tract has been postulated to partly explain its pathogenicity. More frequent identification of Haemophilus parainfluenzae as a causal agent of biliary tract infection would probably be obtained through the use of specific culture media, since its potential implication has been demonstrated.

Anti-Bacterial Agents↗
PubMed2003

Clinical impact of a PCR assay for identification of Staphylococcus aureus and determination of methicillin resistance directly from blood cultures.

We evaluated the clinical usefulness of a PCR assay that discriminates Staphylococcus aureus from coagulase-negative staphylococci and detects methicillin resistance on blood cultures by measuring the adaptation of antimicrobial therapy based on the PCR results. Only 7 of 28 patients (25%) benefited from a modification of antibiotic therapy based on the PCR results, since empirical therapy was appropriate in a majority of cases.

Blood↗
PubMed2002

Evaluation of a triplex PCR assay to discriminate Staphylococcus aureus from coagulase-negative Staphylococci and determine methicillin resistance from blood cultures.

A triplex PCR targeting the 16S rRNA, mecA, and nuc genes was developed for identification of staphylococci and detection of methicillin resistance. After validation of the assay with a collection of strains of staphylococci and enterococci (n = 169), the assay was evaluated with cultures of blood with gram-positive cocci from 40 patients. Accurate results were obtained for 59 (98%) of 61 cultures within 6 h of growth detection.

Bacteremia↗