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D van Soolingen

Publications and source records attributed to D van Soolingen.

At least 73 records · Page 4Linked to original sources
PubMed1998

Analysis of tuberculosis transmission between nationalities in the Netherlands in the period 1993-1995 using DNA fingerprinting.

Immigration from high prevalence areas may contribute to an increased risk of tuberculosis in Europe. This study aimed at quantifying transmission of tuberculosis between and within nationalities among residents of the Netherlands. DNA "fingerprints," on the basis of restriction fragment length polymorphism using marker IS6110, were made of all Mycobacterium tuberculosis isolates in the Netherlands from January 1993 through June 1995. Clusters were defined as groups of patients that had isolates with identical fingerprints. It was assumed that the probability of a patient being the source of a cluster was proportional to the incidence rate of potential sources times the probability that a potential source would give rise to a cluster. The transmission index was defined as the average number of secondary cases of infectious tuberculosis caused directly or indirectly through recent transmission by a single potential source case and was used to estimate the effective reproductive rate associated with recent transmission, ReFAST. Among a total of 623 Dutch tuberculosis cases, 17% (95% confidence interval 9-25%) of cases were attributable to recent transmission from a non-Dutch source. The transmission index varied strongly by nationality, and was highest among the Surinamese (1.3), Moroccan (0.8), and Turkish (0.8) populations; ReFAST was 0.26. Aggregation of tuberculosis cases of given nationalities within clusters was most pronounced among recent immigrants from Somalia and (ex-)Yugoslavia. The authors conclude that differences in transmission between subpopulations can be quantified and may be used to evaluate and direct tuberculosis control.

Adolescent↗
PubMed1998

IS1245 restriction fragment length polymorphism typing of Mycobacterium avium isolates: proposal for standardization.

Mycobacterium avium has become a major human pathogen, primarily due to the emergence of the AIDS epidemic. Restriction fragment length polymorphism (RFLP) typing, using insertion sequence IS1245 as a probe, provides a powerful tool in the molecular epidemiology of M. avium-related infections and will facilitate well-founded studies into the sources of M. avium infections in animal and environmental reservoirs. The standardization of this technique allows computerization of IS1245 RFLP patterns for comparison on a local level and the establishment of M. avium DNA fingerprint databases for interlaboratory comparison. Moreover, by combining international DNA typing results of M. avium complex isolates from a broad spectrum of sources, long-lasting questions on the epidemiology of this major agent of mycobacterial infections will be answered.

AIDS-Related Opportunistic Infections↗
PubMed1998

Diagnosis of Mycobacterium microti infections among humans by using novel genetic markers.

As a result of DNA typing of Mycobacterium microti isolates from animals in the United Kingdom and The Netherlands, we diagnosed four human M. microti infections. These are the first M. microti infections among humans to be reported. Three of the patients were immunocompromised and suffered from generalized forms of tuberculosis. The fourth patient was a 34-year-old immunocompetent male with a persistent cough and undefined X-ray abnormalities. Two of the M. microti infections were recognized by their IS6110 restriction fragment length polymorphism (RFLP) patterns, which showed a high degree of similarity with those of M. microti strains isolated from a pig and a ferret in The Netherlands. The two other human M. microti infections were recognized by using the recently developed DNA fingerprinting method, "spoligotyping," directly on clinical material. All M. microti isolates from the United Kingdom and The Netherlands were found to contain an exceptionally short genomic direct repeat region, resulting in identical two-spacer sequence reactions in spoligotyping. In contrast, the highly similar IS6110 RFLP patterns of the vole strains from the United Kingdom differed considerably from the RFLPs of all M. microti strains isolated in The Netherlands, suggesting that geographic isolation led to divergent strains in the United Kingdom and on the continent.

Adult↗
PubMed1998

Use of IS901 and IS1245 in RFLP typing of Mycobacterium avium complex: relatedness among serovar reference strains, human and animal isolates.

SETTING: Mycobacterium avium complex (MAC) includes major acquired immune deficiency syndrome (AIDS)-associated pathogens. Formerly, MAC serotyping was used for epidemiological purposes. Recently, restriction fragment length polymorphism (RFLP) typing has become available. OBJECTIVE: Examination of the usefulness of insertion sequence IS1245 in RFLP typing of MAC isolates and the association with IS901 RFLP. DESIGN: Ninety-four serovar reference strains were compared with 144 clinical and animal MAC isolates in RFLP typing. RESULTS: All but four strains containing M. avium-specific-rRNA possessed IS1245. Most human isolates showed polymorphic multiband IS1245 patterns, which were associated with serovars 4, 6 and 8. Sequential clinical isolates obtained at up to five years' distance displayed indistinguishable/closely related patterns. Eleven M. paratuberculosis isolates showed indistinguishable six-band patterns. All 29 MAC isolates from 23 bird species, 7/23 from mammals and 1/81 clinical isolates showed an IS1245 three-band pattern, associated with serovars 1, 2 and 3. All these IS1245 'bird' type strains showed closely related IS901 RFLPs. Only three IS1245 'non-bird' type strains contained IS901, but exhibited completely different RFLP patterns. CONCLUSION: IS1245-RFLP typing is useful for the classification of M. avium and epidemiology of most human isolates. The highly conserved IS901 and IS1245 RFLPs among 'bird' type isolates provide proof that these strains constitute a separate taxon within the MAC.

Animals↗
PubMed1998

Origin and management of primary and acquired drug-resistant tuberculosis in The Netherlands: the truth behind the rates.

SETTING: The Netherlands, May 1994 to May 1996. OBJECTIVE: 1) To estimate to what extent drug-resistant tuberculosis was acquired or recently transmitted in The Netherlands, 2) to assess the relevance of drug resistance data as routinely collected, and 3) to describe case management. DESIGN: Prospective descriptive study. Patients diagnosed with drug-resistant tuberculosis were interviewed. Information on patient management and contact tracing was collected. IS6110 restriction fragment length polymorphism (RFLP) patterns of all strains were compared with those of the National RFLP library and clusters were analyzed. RESULTS: In total 193 cases were included in the study. Acquired drug resistance (ADR) was rare. Dutch ADR patients reported receiving treatment a long time previously (mean age 58, mean treatment interval 23 years). Most foreign ADR patients had been treated recently in their country of origin. Of 151 primary drug-resistant (PDR) cases, 129 (85%) were foreign-born, of whom few (8%-19%) had been infected in The Netherlands. Few Dutch PDR cases had been infected recently (mean age 49 years). Rifampicin resistance was more frequently observed in foreign ADR cases than in foreign PDR cases (28% vs 5%; P < 0.001). One third of cases had not been treated according to treatment guidelines. CONCLUSION: Only a small proportion of drug-resistant cases resulted from recent infection or treatment in The Netherlands. General rates of ADR and PDR do not reflect current Dutch programme performance. For programme monitoring, ADR/PDR rates and their trends must be reported and evaluated in Dutch and foreign patients separately.

Adult↗
PubMed1998

Investigation of cross contamination in a Mycobacterium tuberculosis laboratory using IS6110 DNA fingerprinting.

SETTING: A laboratory for routine culturing of Mycobacterium tuberculosis. OBJECTIVE: Investigation of an episode of laboratory cross contamination using IS6110 restriction fragment length polymorphism (RFLP) typing. Improvement of laboratory protocols to prevent contaminations in the future. To stress the importance of 'good laboratory practice', and interaction with clinicians about laboratory results. DESIGN: Fingerprinting of mycobacterial isolates from 1) cultures suspected of being contaminated and 2) strains suspected of being the source of the cross-contamination. RESULTS: RFLP typing results indicated that clinical samples were contaminated by strains which had been processed in species identification procedures one day earlier in the same safety cabinet. This cross contamination also resulted in exceptional RFLP typing results--mixed banding patterns. Three patients were treated on the basis of false-positive laboratory results. Because the laboratory results were confusing for the clinicians, the treatment of one true tuberculosis patient was severely delayed. CONCLUSION: 'Good laboratory practice' is very important to prevent cross contamination. RFLP typing proved to be a useful tool to trace the source of contamination. Interaction with clinicians receiving doubtful results is of the utmost importance.

Bacterial Typing Techniques↗
PubMed1998

Molecular epidemiology of tuberculosis in Cuba outside of Havana, July 1994-June 1995: utility of spoligotyping versus IS6110 restriction fragment length polymorphism.

SETTING: Molecular typing has become an important tool for examining the extent of active transmission of tuberculosis. OBJECTIVES: To examine transmission of tuberculosis in Cuba using IS6110 restriction fragment length polymorphism (RFLP) typing and to evaluate the utility of spoligotyping. DESIGN: One hundred and sixty Mycobacterium tuberculosis strains isolated over a one year period in Cuba were subjected to RFLP and spoligotyping. RESULTS: Forty-eight percent of the isolates were found in 19 clusters of strains with identical RFLP patterns. In general, cluster sizes were limited, except for two large institutional outbreaks. Age was strongly inversely correlated to clustering. Most streptomycin-resistant isolates were found in clusters. Fifteen spoligotype clusters comprised 78% of the isolates. Significantly different IS6110 RFLP types subdivided 11 spoligotype clusters, whereas none of the IS6110 clusters were subdivided by spoligotyping. CONCLUSIONS: Considering the short study period, 48% clustering is high, indicating that recent transmission plays an important role in Cuba. Although resistance is still a minor problem, transmission of streptomycin-resistant strains occurs. The high polymorphism observed with IS6110 RFLP indicates that this marker is useful for future molecular epidemiological studies in Cuba. Spoligotyping appeared less suitable for population-based studies.

Cluster Analysis↗
PubMed1997

A molecular epidemiological approach to studying the transmission of tuberculosis in Amsterdam.

We conducted a retrospective, population-based study with use of restriction fragment length polymorphism (RFLP) analysis to determine the incidence of and risk factors for clustering of Mycobacterium tuberculosis isolates, indicative of recently transmitted infection, among patients with culture-proven tuberculosis diagnosed between 1 July 1992 and 1 January 1995 in Amsterdam. We found that 214 (47%) of 459 patients were in 53 clusters, probably because of recent transmission of M. tuberculosis among 161 (35%) of these patients. Conventional contact tracing resulted in identification of 5.6% of the 161 patients. Clustering was more frequent among Dutch patients (59.3%) than among foreign ethnic patients (42.1%) (P = .002). The independent risk factor for clustering among Dutch patients was younger age; the independent risk factors among foreign ethnic patients were hard-drug use; alcohol abuse; and country of origin (Surinam or the Netherlands Antilles). These findings suggest the shortcomings of the usual tuberculosis control policies in Amsterdam. We identified several risk factors for clustering, which may guide adjustment of tuberculosis control and contact tracing strategies.

Adult↗
PubMed1997

Transmission between HIV-infected patients of multidrug-resistant tuberculosis caused by Mycobacterium bovis.

OBJECTIVE: To investigate outbreaks of multidrug-resistant tuberculosis (TB) by using DNA fingerprint databases. DESIGN: Investigation of two outbreaks of multidrug-resistant TB in separate hospitals in Spain by restriction fragment length polymorphism (RFLP) and spoligotyping. Outbreak strains were compared with more than 1500 RFLPs of Mycobacterium tuberculosis complex strains isolated in Spain and 6000 RFLPs from 30 different countries. METHODS: Standardized IS6110 DNA fingerprinting and 'spoligotyping' was used to type multidrug-resistant isolates belonging to the M. tuberculosis complex amongst the outbreak cases. The DNA types were matched against DNA fingerprint databases in Spain and The Netherlands. RESULTS: The DNA typing analysis indicated that a single multidrug-resistant Mycobacterium bovis strain was responsible for a nosocomial outbreak in a hospital in Spain involving at least 16 HIV-infected patients with non-treatable to multidrug-resistant TB. Introduction of the fingerprint type of this strain to the international database revealed a single matching strain. This strain was also isolated from an HIV-infected patient in The Netherlands who had died from multidrug-resistant TB. This patient had previously been hospitalized in Spain, where a multidrug-resistant TB nosocomial outbreak involving 20 HIV-infected patients was ongoing. The strains causing this outbreak were also identified as M. bovis with an identical DNA pattern to those strains isolated in the Spanish hospital and the patient in The Netherlands. CONCLUSIONS: The use of centralized DNA databases can help to identify rapidly the origin and transmission routes of multidrug-resistant TB across international boundaries and the potential use of such an early warning surveillance system for investigation of nosocomial multidrug-resistant TB outbreaks between HIV-infected patients. To our knowledge this is the first report of transmission of multidrug-resistant M. bovis between hospitals.

Bacterial Typing Techniques↗
PubMed1997

A novel pathogenic taxon of the Mycobacterium tuberculosis complex, Canetti: characterization of an exceptional isolate from Africa.

In an attempt to characterize an unusual mycobacterial strain isolated from a 2-year-old Somali patient with lymphadenitis, we applied various molecular methods not previously used for the taxonomic classification of mycobacteria. This isolate, designated So93, did not differ from Mycobacterium tuberculosis in the biochemical tests and in its 16S rRNA sequence, but produced smooth and glossy colonies, which is highly exceptional for this species. This smooth phenotype was unstable and switched nonreversibly to a rough colony morphology with a low frequency. The two colony types were equally virulent for the guinea pig, exhibiting characteristic tuberculous disease. Both morphotypes had shorter generation times than the M. tuberculosis reference laboratory strain H37Rv and clinical isolates of M. tuberculosis and Mycobacterium bovis. Furthermore, the So93 isolate differed from all M. tuberculosis complex strains described thus far by having only a single copy of insertion sequence IS1081, an unusual composition of the direct repeat cluster, and a characteristic phenolic glycolipid and lipooligosaccharide. This glycolipid had previously been observed only in a smooth isolate of M. tuberculosis obtained in 1969 by Canetti in France. Analysis of the Canetti strain showed that it shared virtually all genetic properties characteristic of So93, distinguishing these two strains from the known M. tuberculosis complex taxa, M. tuberculosis, Mycobacterium africanum, M. bovis, and Mycobacterium microti. The natural reservoir, host range, and mode of transmission of the group of bacteria described in this paper are presently unknown. This study, partly based on not previously used molecular criteria, supports the idea that the established members within the M. tuberculosis complex and the newly described Canetti grouping should be regarded as a single species, which likely will be designated "M. tuberculosis".

Animals↗
PubMed1997

Simultaneous detection and strain differentiation of Mycobacterium tuberculosis for diagnosis and epidemiology.

Widespread use of DNA restriction fragment length polymorphism (RFLP) to differentiate strains of Mycobacterium tuberculosis to monitor the transmission of tuberculosis has been hampered by the need to culture this slow-growing organism and by the level of technical sophistication needed for RFLP typing. We have developed a simple method which allows simultaneous detection and typing of M. tuberculosis in clinical specimens and reduces the time between suspicion of the disease and typing from 1 or several months to 1 or 3 days. The method is based on polymorphism of the chromosomal DR locus, which contains a variable number of short direct repeats interspersed with nonrepetitive spacers. The method is referred to as spacer oligotyping or "spoligotyping" because it is based on strain-dependent hybridization patterns of in vitro-amplified DNA with multiple spacer oligonucleotides. Most of the clinical isolates tested showed unique hybridization patterns, whereas outbreak strains shared the same spoligotype. The types obtained from direct examination of clinical samples were identical to those obtained by using DNA from cultured M. tuberculosis. This novel preliminary study shows that the novel method may be a useful tool for rapid disclosure of linked outbreak cases in a community, in hospitals, or in other institutions and for monitoring of transmission of multidrug-resistant M. tuberculosis. Unexpectedly, spoligotyping was found to differentiate M. bovis from M. tuberculosis, a distinction which is often difficult to make by traditional methods.

Bacterial Typing Techniques↗
PubMed1997

Use of DNA fingerprinting in international source case finding during a large outbreak of tuberculosis in The Netherlands.

SETTING: Tuberculosis outbreak in a low prevalence country. OBJECTIVE: Description of an international source tracing process in which restriction fragment length polymorphism (RFLP) analysis played an essential role. DESIGN: In 1993 a large scale source tracing process was initiated in Harlingen, a harbour town in the north of The Netherlands, after a child with tuberculous meningitis was reported for which no source could be identified. Traditional contact tracing followed the detection of sources of infection. RFLP was used to map the tuberculosis transmission and identify the source case. RESULTS: The investigation extended from the north to several places in the west of The Netherlands. In total 6519 persons were screened; there were 276 infections, among which 49 cases of active tuberculosis were identified. RFLP analysis of Mycobacterium tuberculosis isolates from all 28 culture positive patients showed the 'Harlingen' type DNA fingerprint. After 5 months source tracing led to the identification of the source case in the United Kingdom. Up to June 1996 altogether 37 patients (The Netherlands 28; the UK 7; Surinam 1; Morocco 1) were found to have isolates with the Harlingen type DNA pattern. Despite a thorough evaluation, in 5 of the 37 patients no relation to the source case or the outbreak in Harlingen could be established. CONCLUSION: RFLP typing proved a very useful instrument in guiding the process of international source tracing and contact investigation.

Adolescent↗
PubMed1996

[Transmission of sensitive and resistant strains of Mycobacterium tuberculosis in The Netherlands, 1993-1995, studied by means of DNA fingerprinting].

OBJECTIVE: Determination of the contribution of recent transmission of both sensitive and drug-resistant Mycobacterium tuberculosis strains to the number of tuberculosis cases in the Netherlands. DESIGN: Descriptive study. SETTING: National Institute for Public Health and Environment, Bilthoven, the Netherlands. METHODS: Since 1993 all isolates of M. tuberculosis in the Netherlands are sent to the national reference laboratory for surveillance purposes. The strains with IS6110 DNA fingerprint, isolated from January 1993 to July 1995, were analysed for clustering of DNA patterns (clustering of identical DNA patterns was assumed to represent recent transmission of tuberculosis). A transmission index was calculated from the ratio of the number recently infected tuberculosis patients and the number of source patients. RESULTS: Among 2,217 M. tuberculosis isolates, 1,313 unique DNA fingerprints were observed, while 264 DNA patterns occurred more than once. 904 (41%) DNA fingerprints were part of a cluster of identical fingerprints. The mean cluster size was 3.42. The 232 resistant strains showed significantly less clustering (33% versus 42%, p < 0.02) and a smaller transmission index (0.27 versus 0.42, p < 0.02) compared with sensitive strains. CONCLUSION: Recent transmission contributes to the magnitude of the tuberculosis problem in the Netherlands. The epidemiological situation would, however, lead to gradual elimination of the disease were it not for introduction of tuberculosis from other countries. Transmission of resistant strains is relatively limited. Micro-epidemics caused by resistant M. tuberculosis strains were not observed.

DNA Fingerprinting↗
PubMed1996

[Border-crossing source tracing in tuberculosis via DNA fingerprint technique].

OBJECTIVE: Description of the value of modern DNA analysis ('restriction fragment length polymorphism'; RFLP) as a method for mapping tuberculosis transmission. DESIGN: Descriptive. SETTING: Social Health Service Noord-Friesland, the Netherlands. METHOD: A large-scale tuberculosis investigation was conducted in Harlingen in 1993 when a 2,5 year old patient with tuberculous meningitis was reported. Source tracing and contact tracing extended from Harlingen to the west of the Netherlands and even abroad. Modern DNA analysis (RFLP) was used to map the tuberculosis transmission. RESULTS: A total of 6519 persons were screened and 276 infected people were identified, of whom 49 were suffering from active tuberculosis. RFLP analysis showed in 27 of them a 'Harlingen' type Mycobacterium tuberculosis DNA pattern identical to that of the index patient. The source patient was finally traced in England. By the end of 1994 3 more patients were found with the same DNA pattern; their relation with the source patient and the outbreak of tbc remained unrevealed. CONCLUSION: The Harlingen outbreak was extensive and characterized by time-consuming source tracing. Modern DNA analysis proved to be a very useful instrument in identifying the source case.

Adult↗