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Henri Verbrugh

Publications and source records attributed to Henri Verbrugh.

At least 19 recordsLinked to original sources
PubMed2006

Translationally controlled tumor protein from Madurella mycetomatis, a marker for tumorous mycetoma progression.

About 40 years ago Abs against the fungus Madurella mycetomatis were first demonstrated to be present in eumycetoma patients, a disease characterized by tumorous swellings. To date nothing is known about the individual immunoreactive Ags present in this fungus. In the present study, we identify its first immunogenic Ag, a protein homologous to the translationally controlled tumor protein (TCTP), a well-conserved histamine release factor in a range of eukaryotes. The gene for this Ag was demonstrated to be present in two variants in M. mycetomatis, with 13% aa difference between the two proteins encoded. In vitro, TCTP was secreted into the culture medium. In vivo, it was found to be expressed on hyphae present in developing stages of the eumycetoma-characteristic black grain. Significant IgG and IgM immune responses, against the whole protein and selected M. mycetomatis-specific peptides, were determined. The Ab levels correlated with lesion size and disease duration. Overall, the patients with the largest lesions had the highest Ab level, which lowered with decreasing size of the lesion. After 6-15 years of disease duration the Ab levels were the highest. TCTP is the first well-characterized immunogenic Ag, simultaneously the first monomolecular vaccine candidate, identified for the fungus M. mycetomatis.

Adult↗
PubMed2005

Staphylococcus aureus nasal carriage is not associated with known polymorphism in the Vitamin D receptor gene.

The vitamin D endocrine system has been shown to influence the immune response and polymorphisms in the vitamin D receptor (VDR) gene have been associated with susceptibility to infectious diseases. We determined if the Cdx2, FokI and BsmI-ApaI-TaqI polymorphisms in the VDR gene were associated with nasal carriage of Staphylococcal aureus. We defined the S. aureus nasal carriage status (persistent, intermittent or non-carriage) for a group of more that 2000 elderly volunteers. The prevalence of persistent S. aureus nasal carriage was 18%, which was, however, not associated with any of the variant VDR genotypes. Our study into genetic determinants of S. aureus carriage patterns is the largest in the field, but still we found no association between VDR gene variation and S. aureus nasal carriage.

Aged↗
PubMed2005

Major epidemic clones of Staphylococcus aureus in Nigeria.

Clinical isolates of Staphylococcus aureus (n=276) were collected in 10 different hospitals located in the Southwest (cities of Ibadan and Lagos) and North-Central (city of Jos) parts of Nigeria. Resistance profiling of these strains revealed that the vast majority was still susceptible to methicillin (98.6% MSSA). Pulsed field gel electrophoresis (PFGE) performed for these strains identified 45 different genotypes, nine of which were identified in four or more different hospitals. The major PFGE type (genotype 2) comprised 23% of all isolates. In addition, several other strains were shown to be endemic in individual hospitals. Three out of four multi-resistant MRSA strains that were detected were sequence type 8 (ST8) as determined by array-based multi-locus sequence typing (MLST). PCRs for cataloguing the staphylococcal cassette chromosome (SCCmec) type were negative for two of these, suggesting the existence of a new methicillin-resistance gene complex in the ST8 genetic background. In conclusion, major clones of MSSA circulate in Nigeria, and the MRSA incidence is still low. However, the occurrence of old and new versions of SCCmec in some of the ecologically abundant MSSA strains should be taken as a serious warning since clonal expansion of this type of strains is not unprecedented.

Genotype↗
PubMed2005

Genotyping of Madurella mycetomatis by selective amplification of restriction fragments (amplified fragment length polymorphism) and subtype correlation with geographical origin and lesion size.

One of the causative organisms of mycetoma is the fungus Madurella mycetomatis. Previously, extensive molecular typing studies identified Sudanese isolates of this fungus as clonal, but polymorphic genetic markers have not yet been identified. Here, we report on the selective amplification of restriction fragment (AFLP) analysis of 37 Sudanese clinical isolates of M. mycetomatis. Of 93 AFLP fragments generated, 25 were polymorphic, and 12 of these 25 polymorphic fragments were found in a large fraction of the strains. Comparative analysis resulted into a tree, composed of two main (clusters I and II) and one minor cluster (cluster III). Seventy-five percent of the strains found in cluster I originated from central Sudan, while the origin of the strains in cluster II was more heterogeneous. Furthermore, the strains found in cluster I were generally obtained from lesions larger than those from which the strains found in cluster II were obtained (chi-square test for trend, P = 0.03). Among the 12 more commonly found polymorphisms, 4 showed sequence homology with known genes. Marker A7 was homologous to an endo-1,4-beta-glucanase from Aspergillus oryzae, 97% identical markers A12 and B3 matched a hypothetical protein from Gibberella zeae, and marker B4 was homologous to casein kinase I from Danio rerio. The last marker seemed to be associated with strains originating from central Sudan (P = 0.001). This is the first report on a genotypic study where genetic markers which may be used to study pathogenicity in M. mycetomatis were obtained.

Antifungal Agents↗
PubMed2004

A novel plasmid (pEMCJH03) isolated from moraxella catarrhalis possibly useful as a cloning and expression vector within this species.

A preliminary screening study of six Moraxella catarrhalis isolates from primary school children in the Netherlands identified a small 3.5 kb plasmid (pEMCJH03), containing four open reading frames, which encoded three mobilizing and one replicase protein. Insertion of a kanamycin containing transposon (yielding pEMCJH04) allowed selection and isolation of the plasmid in Escherichia coli. Natural transformation of pEMCJH04 into M. catarrhalis was successful for 25% (3/12) of non-isogenic isolates, with no link between (lack of) transformability and genetic lineage or (lack of) transformability and complement phenotype, though the transformation efficiency was found to be rather low at approximately 615CFU/microg (range=60-1040CFU/microg ). This is only the second publication detailing a plasmid isolated from this important respiratory pathogen, and the ability to clone and express foreign proteins in M. catarrhalis using pEMCJH04 could help in the development of a vaccine expression vector, as well as providing a useful tool for studying promoter activity and in complementation studies of gene knockout mutants.

Bacterial Proteins↗
PubMed2004

Molecular epidemiology of Staphylococcus aureus colonization in a burn center.

The aim of this study was to investigate carriage of Staphylococcus aureus by patients and health care workers (HCW) and to define the genetic relationship of S. aureus strains isolated from burn wounds. At admission, 19/55 (34.5%) patients carried S. aureus in their nose and/or throat. Of this group, 95% subsequently colonized their burn wounds with S. aureus. Molecular analysis showed that in 78% of these cases the burn-wound colonizing strain was identical to the strain carried at admission. Importantly, 23/36 (64%) patients who did not carry S. aureus at admission also developed burn-wound colonization. In this group, three dominant genotypes were identified as colonizing strains of burn wounds. These clones represented also the majority (59%) of S. aureus strains cultured from the nose and/or throat of health care workers and patients. If patients were admitted to one of the Intensive Care rooms burn wounds of non-carriers were not colonized with S. aureus as long as they remained in such isolation. Only patients who carried S. aureus at admission developed burn-wound colonization with that genotype they carried in the nose or throat. Both carriage in patients and health care workers and auto-infection play a crucial role in (cross-) colonization events.

Adult↗
PubMed2004

A new high-throughput AFLP approach for identification of new genetic polymorphism in the genome of the clonal microorganism Mycobacterium tuberculosis.

We have here applied high-throughput amplified fragment length polymorphism (htAFLP) analysis to strains belonging to the five classical species of the Mycobacterium tuberculosis complex. Using 20 strains, three enzyme combinations and eight selective amplification primer pairs, 24 AFLP reactions were performed per strain. Overall, this resulted in 480 DNA fingerprints and more than 1200 htAFLP-amplified PCR fragments were visualised per strain. The cumulative dendrogram correctly clustered strains from the various species, albeit within a distance of 6.5% for most of them. The single isolate of Mycobacterium canettii presented separately at 19% distance. All over, 169 fragments (14%) appeared to be polymorphic. Sixty-eight were specific for M. canetti and forty-five for Mycobacterium bovis. For the 10 different M. tuberculosis strains included in the present analysis, 56 polymorphic markers were identified. Upon sequencing 20 of these marker regions and comparisons with the H37Rv genome sequence, 25% appeared to share homology to members of the antigenically variable PE/PPE surface protein encoding gene family confirming previous findings on the genetic heterogeneity within these genes. In addition, homologues for phage genes and insertion element-encoded genes were detected. Forty-five percent of the sequences derived from ORFs with a currently unknown function, which was corroborated by genome sequence comparison for the clinical M. tuberculosis CD 1551 isolate. Sequence variation in M. tuberculosis was assessed in more detail for a subset of these loci by newly designed PCR restriction fragment length polymorphism (RFLP) tests and direct sequencing. Fourteen novel PCR RFLP tests were developed and twelve novel single nucleotide polymorphisms (SNPs) were identified, all suited for epidemiological analysis of M. tuberculosis. The tests allowed for identification of the major Mycobacterium species and M. tuberculosis variants and clones.

Cluster Analysis↗
PubMed2004

Mycetoma caused by Madurella mycetomatis: a neglected infectious burden.

Tropical eumycetoma is frequently caused by the fungus Madurella mycetomatis. The disease is characterised by extensive subcutaneous masses, usually with sinuses draining pus, blood, and fungal grains. The disease affects individuals of all ages, although disability is most severe in adults who work outdoors. Compared with major diseases such as tuberculosis, malaria, and HIV, disease from M mycetomatis is underestimated but socioeconomically important. Many scientific case reports on mycetoma exist, but fundamental research was lacking until recently. We present a review on developments in the clinical, epidemiological, and diagnostic management of M mycetomatis eumycetoma. We describe newly developed molecular diagnostic and gene typing procedures, and their application for management of patients and environmental research. Fungal susceptibility tests have been developed as well as a mouse model of infection. These advances should greatly further our understanding of the molecular basis of eumycetoma.

Animals↗
PubMed2004

Human factor in Staphylococcus aureus nasal carriage.

Persistent nasal carriers and noncarriers of Staphylococcus aureus were inoculated with a mixture of different S. aureus strains. The majority of noncarriers and nearly all persistent carriers returned to their original carrier state after artificial inoculation. Furthermore, the majority of persistent carriers tested positive again for their original resident strain. Using a human nasal inoculation model, we here demonstrate that the human factor is an important determinant of S. aureus nasal carriage.

Carrier State↗
PubMed2003

Strict infection control measures do not prevent clonal spread of coagulase negative staphylococci colonizing central venous catheters in neutropenic hemato-oncologic patients.

Coagulase negative staphylococci (CoNS) are a main cause of catheter related infections (CRI). Earlier studies (1994-1996) revealed a high incidence of CRI (6 per 1000 catheter days) among neutropenic hemato-oncologic patients in the Erasmus MC Hematology Department (Rotterdam, The Netherlands). This was mainly explained by expansion of two methicillin resistant Staphylococcus epidermidis (MRSE) clones (Nouwen et al., J. Clin. Microbiol. 36 (1998) 2696-2702). In a new, 16-bed unit in the same institution, we investigated the effect of strict clinical isolation measures on the incidence of CRI. During two 6-month screening periods (period I: April 1998-December 1998 and period II: April 1999-October 1999) all patients receiving a central venous catheter were prospectively monitored for the development of CRI. During period I every visitor of the cubicles had to wear hair caps, masks, gowns and gloves. During period II these procedures were abolished, but hands were cleansed using alcohol and masks were worn during both periods in case of coughing and sneezing. All CoNS strains isolated from blood cultures were genetically classifies by pulsed field gel electrophoresis (PFGE). The incidence of CRI during period I was 13.0 per 1000 catheter days, in comparison to 9.6 in period II (P=0.84). During this latter period, 19 CRI were diagnosed, 14 catheter related bacteremia episodes (CRB) and five local infections. Seventy-two percent (n=9) of CRB were due to a CoNS. The mean catheter survival until appearance of a CRI increased from 43 days during period I to 78 days in period II (P=0.39). The mean catheter survival until infection related removal was increased from 43 days to 133 days (P=0.12). During period I less experienced intervention radiologists introduced the catheters, which may have limited the efficacy of the strict hygiene measures. Thus, abolishing strict isolation precautions had no negative effect on the incidence of CRI. After genotyping of 38 MRSE strains isolated from blood and central venous catheter cultures of 12 patients in period II, eight PFGE types were found. Three types were found in more than one patient, but based on epidemiological data patient-to-patient spread could not be proven. No genotypic identity between patient and personnel CoNS isolates was shown and the two major clonal types that were present between 1994 and 1996 were not encountered. However, from December 1998 onwards new MRSE clones could be identified (types E and J). In conclusion, despite a constant rate of CRI and implementation of optimal patient care, clonal spread of MRSE strains was not prevented by strict hygiene measures.

Catheterization, Central Venous↗
PubMed2003

Total genome polymorphism and low frequency of intra-genomic variation in the uspA1 and uspA2 genes of Moraxella catarrhalis in otitis prone and non-prone children up to 2 years of age. Consequences for vaccine design?

Intra-genomic variation in the uspA1 and uspA2 genes of Moraxella catarrhalis was studied using pulsed field gel electrophoresis (PFGE) and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. From a set of 91 M. catarrhalis isolates, 19 pairs of PFGE identical isolates were found. Five pairs originated from otitis non-prone children, 11 pairs from otitis prone children and for 3 pairs, one of the pair originated from an otitis prone and the other from an otitis non-prone child. No particular M. catarrhalis isolate was associated with either the otitis prone or non-prone children. One of these 19 pairs of isolates was found to exhibit both uspA1 and uspA2 intra-genomic variation, whilst another pair exhibited uspA2 intra-genomic variation only. Sequence data obtained from these variants showed that PCR-RFLP pattern differences reflected actual changes in predicted amino acid composition and that minor amino acid changes in a 23 base pair "NINNIY" repeat region (a conserved UspA1 and UspA2 binding site for the neutralising antibody mAb17C7) occurred. Variation in the uspA2 5' non-coding "AGAT" repeat region was also observed. These results may have implications for future M. catarrhalis vaccines comprising UspA1 or UspA2 components.

Amino Acid Sequence↗
PubMed2003

Madurella mycetomatis strains from mycetoma lesions in Sudanese patients are clonal.

Molecular diversity among clinical isolates of Madurella mycetomatis, the prime fungal agent of human mycetoma in Sudan, could possibly explain the diverse clinical presentations of this severely debilitating infectious disease. In addition, culture-independent DNA-mediated typing tests need to be developed for this organism, since M. mycetomatis DNA, but not the organism itself, can be identified in soil, the material from which infections are thought to originate. A collection of 38 different clinical M. mycetomatis isolates was characterized by large-scale random amplification of polymorphic DNA using 20 different primer species. These analyses, involving at least 2,600 annealing sites, showed a complete lack of DNA fingerprint variation among the various isolates. From the resulting homogeneous DNA fingerprints, seven fragments were cloned and sequenced, and novel, species-specific PCR restriction fragment length polymorphism (RFLP) tests were designed. The seven PCR RFLP tests were successfully performed on the 38 different M. mycetomatis strains. However, again all M. mycetomatis DNA patterns obtained appeared to be identical, whereas patterns produced using DNAs from other fungal species were clearly discriminatory. These results suggest that there is little genetic variation among clinically relevant M. mycetomatis strains from Sudan. The data tentatively imply that different manifestations of mycetoma are due to differences in host susceptibility rather than differential virulence of the causative agent.

DNA Primers↗
PubMed2003

Patterns of resistance associated with integrons, the extended-spectrum beta-lactamase SHV-5 gene, and a multidrug efflux pump of Klebsiella pneumoniae causing a nosocomial outbreak.

Multiresistant Klebsiella pneumoniae caused a nosocomial outbreak. Resistance patterns of the presumed outbreak isolates varied among and within patients. In order to control the outbreak, screening for extended-spectrum beta-lactamase (ESBL)-producing K. pneumoniae was commenced. A number of susceptible K. pneumoniae strains were stored to serve as controls in genetic strain typing. Typing by pulsed-field gel electrophoresis proved the clonality of the strains in the recognized outbreak patients. Typing of the control strains by pulsed-field gel electrophoresis showed that at least one patient had been missed by the ESBL screening procedure. Further genetic typing confirmed the presence of the SHV-5 ESBL gene in all but one of the outbreak strains. Variable presence of integrons that carried the aminoglycoside resistance genes aadB and aadA2 was found. A gyrA mutation in codon 83 was present in all outbreak strains tested, despite considerable differences in ciprofloxacin MICs. The MICs of ciprofloxacin and the chemically unrelated drug cefoxitin were correlated (r = 0.86, P < 0.01) and were compatible with the overexpression of an efflux pump in a subset of the outbreak strains. We conclude that outbreak strains that express an ESBL gene only at a low level may pass unnoticed in a screening procedure, when the laboratory is unaware of variable ESBL expression. In this particular outbreak, screening for strains for which ciprofloxacin MICs were > or =0.25 micro g/ml would in retrospect have been the most sensitive method for detection of the K. pneumoniae outbreak strain.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed2003

Severity of nonbullous Staphylococcus aureus impetigo in children is associated with strains harboring genetic markers for exfoliative toxin B, Panton-Valentine leukocidin, and the multidrug resistance plasmid pSK41.

Nonbullous impetigo is a common skin infection in children and is frequently caused by Staphylococcus aureus. Staphylococcal toxins and especially exfoliative toxin A are known mediators of bullous impetigo in children. It is not known whether this is also true for nonbullous impetigo. We set out to analyze clonality among clinical isolates of S. aureus from children with nonbullous impetigo living in a restricted geographical area in The Netherlands. We investigated whether staphylococcal nasal carriage and the nature of the staphylococcal strains were associated with the severity and course of impetigo. Bacterial isolates were obtained from the noses and wounds of children suffering from impetigo. Strains were genetically characterized by pulsed-field gel electrophoresis-mediated typing and binary typing, which was also used to assess toxin gene content. In addition, a detailed clinical questionnaire was filled in by each of the participating patients. Staphylococcal nasal carriage seems to predispose the patients to the development of impetigo, and 34% of infections diagnosed in the Rotterdam area are caused by one clonal type of S. aureus. The S. aureus strains harbor the exfoliative toxin B (ETB) gene as a specific virulence factor. In particular, the numbers (P = 0.002) and sizes (P < 0.001) of the lesions were increased in patients infected with an ETB-positive strain. Additional predictors of disease severity and development could be identified. The presence of a staphylococcal plasmid encoding multiple antibiotic resistance traits, as detected by binary typing, was associated with a reduction in the cure rate. Our results recognize that a combination of staphylococcal virulence and resistance genes rather than a single gene determines the development and course of nonbullous impetigo. The identification of these microbial genetic markers, which are predictive of the severity and the course of the disease, will facilitate guided individualized antimicrobial therapy in the future.

Anti-Bacterial Agents↗
PubMed2003

Recent emergence of an epidemic clindamycin-resistant clone of Clostridium difficile among Polish patients with C. difficile-associated diarrhea.

Analysis of both the antibiotic resistance and the virulence characteristics of anaerobic human microbial pathogens is important in order to improve our understanding of a number of clinically significant infectious diseases, including Clostridium difficile-associated diarrhea (CDAD). We determined the presence of the clindamycin resistance-associated gene ermB and the ribotype of 33 C. difficile strains isolated from Polish patients suffering from CDAD. While all strains produced cytotoxin B (TcdB), enterotoxin A (TcdA) was produced by a subset of 15 strains only. The results showed that a single ermB-positive, TcdA(-)B(+) C. difficile strain with ribotype A has disseminated widely in the two Warsaw hospitals under investigation. Although different strains with the same phenotype were detected, the genotype A strain appeared to be the only one with a clear epidemic character. Apparently, enhanced local spread of CDAD-causing C. difficile may be restricted to a limited number of bacterial genotypes only.

Anti-Bacterial Agents↗
PubMed2002

Attachment of Staphylococcus aureus to eukaryotic cells and experimental pitfalls in staphylococcal adherence assays: a critical appraisal.

Staphylococcus aureus is a bacterial species with pathogenic potential to both humans and animals. The primary natural niche is said to be the human vestibulum nasi from where bacterial cells may spread to the environment or additional anatomical sites such as the perineum or the hands, where residence is usually transient. Apparently, S. aureus is capable of a precise and balanced interaction with specific types of eukaryotic nasal cells. Although a wide variety of important bacterial ligands and possible eukaryote receptors have been described, the precise mechanisms leading to persistent bacterial colonization and, even more importantly, associated infection have not yet been elucidated in detail. This may be a consequence of the fact that most of the adherence factors have been studied individually in simplified in vitro systems, not taking the complexity of multi-factorial in vivo cell-cell interactions into account. An overall scheme of the initial and sequential interactions leading to S. aureus colonization of eukaryotic cell surfaces has not yet emerged. This review concisely describes the current state of affairs in the multi-disciplinary field of staphylococcal adherence research. Specific emphasis is placed upon the pros and cons of the various artificial, mostly in vitro models employed to study the interaction between bacterial and human or animal cells.

Animals↗
PubMed2002

Validation of rapid screening tests for the identification of methicillin resistance in staphylococci.

The Velogene Rapid MRSA Identification Assay (Alexon-Trend Inc., Ramsey, MN), a commercially available 90-min genotypic test using a chimeric probe for the cycling-mediated recognition of the mecA gene in staphylococci, was compared with the MRSA-Screen latex agglutination test, a 15-min phenotypic test (Denka Seiken Co., Tokyo, Japan) for the identification of the mecA gene product PBP 2a. The results of both techniques were compared with mecA gene PCR. A total of 210 stock-culture strains were tested, consisting of 108 methicillin-susceptible Staphylococcus aureus (MSSA) strains and 92 methicillin-resistant S. aureus (MRSA) strains. The performance of the assays was good, displaying sensitivities and specificities for Velogene and MRSA Screen of 96.7% and 100% and 96.7% and 100%, respectively. Both Velogene and MRSA Screen could not correctly identify three of the MRSA strains each. Repeat testing with a larger inoculum or exposure of the three distinct strains to methicillin, respectively, resolved these problems. All MSSA strains as well as the other genera were correctly addressed by both techniques. The 10 methicillin-resistant Staphylococcus epidermidis strains were detected by both techniques. Both the Velogene and the MRSA Screen assays accurately identified mecA-positive staphylococcal strains and can be successfully used for routine application in clinical microbiology laboratories.

Bacterial Proteins↗