The European Centre for Disease Prevention and Control (ECDC) and the European Respiratory Society (ERS) jointly developed European Union Standards for Tuberculosis Care (ESTC) aimed at providing European Union (EU)-tailored standards for the diagnosis, treatment and prevention of tuberculosis (TB).The International Standards for TB Care (ISTC) were developed in the global context and are not always adapted to the EU setting and practices. The majority of EU countries have the resources and capacity to implement higher standards to further secure quality TB diagnosis, treatment and prevention. On this basis, the ESTC were developed as standards specifically tailored to the EU setting.A panel of 30 international experts, led by a writing group and the ERS and ECDC, identified and developed the 21 ESTC in the areas of diagnosis, treatment, HIV and comorbid conditions, and public health and prevention. The ISTCs formed the basis for the 21 standards, upon which additional EU adaptations and supplements were developed.These patient-centred standards are targeted to clinicians and public health workers, providing an easy-to-use resource, guiding through all required activities to ensure optimal diagnosis, treatment and prevention of TB. These will support EU health programmes to identify and develop optimal procedures for TB care, control and elimination.
Since Robert Koch described the cause of tuberculosis in 1882, the natural history of the disease after primary infection has been subject to debate. Only approximately 10% of infected individuals develop active disease, which may appear years to decades after infection. Late onset has been attributed to the endogenous reactivation of dormant bacteria. However, this has not been documented by molecular means for latencies of more than a few years. In Denmark, we have recently recultured 205 freeze-dried Mycobacterium tuberculosis strains obtained from 1961 through 1967. These "historical" strains are analyzed by DNA restriction fragment-length polymorphism testing, and their DNA patterns are compared with those of 4008 recently obtained clinical specimens. This has, surprisingly, yielded molecular evidence of M. tuberculosis reactivation after 33 years of latent infection. A father and son who developed tuberculosis in 1961 and in 1994, respectively, were the only patients infected with strains that share an identical DNA pattern.
BackgroundTuberculous meningitis is the most severe manifestation of extrapulmonary tuberculosis with a high mortality rate and a high rate of sequelae among survivors. The aim of this study is to assess the current epidemiology, clinical features, diagnostic procedures, treatment and outcome in patients with tuberculous meningitis in Denmark, a country with a low tuberculosis incidence.MethodsA nationwide retrospective study was conducted, comprising all patients notified with tuberculous meningitis (TBM) in Denmark from 2000-2008. Medical records were reviewed using a standardised protocol.ResultsFifty patients, including 12 paediatric patients, were identified. 78% of the patients were immigrants from countries of high tuberculosis endemicity. 64% of all patients had a pre-existing immunosuppressive condition; 10% were HIV positive, 48% were HIV seronegative and 42% had an unknown HIV status. Median symptom duration before admission was 14 days in the Danish patient population and 20 days in the immigrant group. Biochemical analysis of cerebrospinal fluid (CSF) samples revealed pleocytosis in 90% with lymphocyte predominance in 66%. Protein levels were elevated in 86%. The most common findings on neuro-radiological imaging were basal meningeal enhancement, tuberculomas and hydrocephalus. Lumbar puncture was performed on 42 patients; 31 of these specimens (74%) had a positive CSF culture for mycobacteria and 9.5% were smear positive for acid-fast bacilli. The overall mortality rate was 19% and 48% of the remaining patients had neurological sequelae of varying degree.ConclusionTBM is a rare but severe manifestation of extrapulmonary TB in Denmark. The clinician must be prepared to treat empirically if the suspicion of TBM has arisen to improve treatment outcome.
Tuberculosis patients may harbor both drug-susceptible and -resistant bacteria, i.e., heteroresistance. We used mixtures of rifampin-resistant and -susceptible Mycobacterium tuberculosis strains to simulate heteroresistance in patient samples. Molecular tests can be used for earlier discovery of multidrug resistance (MDR), but the sensitivity to detect heteroresistance is unknown. Conventional phenotypic drug susceptibility testing was the most sensitive, whereas two line probe assays and sequencing were unable to detect the clinically important 1% resistant bacteria. Patients with tuberculosis (TB) that harbor drug-susceptible Mycobacterium tuberculosis strains may also have a small proportion of drug-resistant bacteria that develops spontaneously during replication, normally at a rate of 10 Ϫ8 to 10 Ϫ9 mutations/ cell division (1). For rifampin (Rif) resistance, mutations are almost exclusively found in a single gene, rpoB (2). Conventional drug susceptibility testing (DST) aims to determine if 1% or more of the bacterial population in clinical specimens is drug resistant (3, 4). In this study, cultures that contain both susceptible and at least 1% resistant bacteria are defined as heteroresistant. Heteroresistance is thought to be an early stage in the development of drug-resistant TB in a patient. In such cases, failing to detect resistance may lead to insufficient treatment and treatment failure. As a consequence, spread of resistant bacteria may occur in the future (5). The prevalence of heteroresistance is unknown and is presumably dependent on the local resistance epidemiology. Findings of heteroresistance are accidental, and simple methods for the detection are needed (6).In recent years, a number of genotypic methods have become available for rapid detection of mutations that may confer resistance. Molecular tests have been recommended for use worldwide, with the objective of earlier discovery of multidrug resistance (MDR) (http://www.who.int/tb/features_archive/policy _statement.pdf). These assays are important for the global scaling up of detection of MDR-TB. However, little is known of the sensitivity of these methods to detect resistance in heteroresistant specimens. The aim of the present study was to evaluate the ability of different DST methods to detect Rif resistance when heteroresistance is present.Two freeze-dried strains each of the spoligo families Haarlem and Beijing were obtained from the WHO Tropical Disease Research (TDR) TB Strain Bank. The Haarlem strain TB-TDR-063 was susceptible, and TB-TDR-165 was Rif resistant with the rpoB H526Y mutation. The Beijing strain TB-TDR-077 was susceptible, and TB-TDR-068 was Rif resistant with the rpoB S531L mutation. The susceptible strains from both families had wild-type (WT) DNA in rpoB. The strains were subcultured in Dubos with 0.045% Tween 80 (SSI Diagnostika, Hilleroed, Denmark) with 1 mg/ml Rif (BD, Franklin Lakes, NJ) diluted in water for the resistant strains. After 2 weeks of incubation at 37°C, the bacterial concentrations in liquid medi...
In 1903, Niels Ryberg Finsen was awarded the Nobel Prize for his invention of light therapy for skin tuberculosis (lupus vulgaris). The mechanism of action has not been shown; thus, we wanted to elucidate the mechanism of Finsen's light therapy. We measured radiation that could be transmitted through his lens systems and absorption of the stain solution filters in the lamps, and related the obtained results to the possible biological effects on Mycobacterium tuberculosis. Judged from transmission characteristics all tested lens systems were glass lenses (absorbing wavelength < 340 nm). The tested filters likewise absorbed wavelengths < 340 nm. The methylene blue solution used to absorb heat, blocked out wavelengths below 340 nm and between 550 and 700 nm. Furthermore, fluorescence of M. tuberculosis indicated the presence of porphyrins and HPLC analysis of sonicated M. marinum showed that coproporphyrin III was present, which highly justified that porphyrins were present in M. tuberculosis. Production of singlet oxygen through radiation of porphyrins with light of e.g. 400 nm seems to be a most plausible explanation why Finsen's therapy worked in spite of the lack of shortwave ultraviolet radiation, which Finsen believed was the most effective radiation for treating skin tuberculosis.
BackgroundSince non-tuberculous mycobacteria (NTM) disease is not notifiable in most European Union (EU) and European Economic Area (EEA) countries, the epidemiological situation of the >150 NTM species is largely unknown. We aimed to collect data on the frequency of NTM detection and NTM species types in EU/EEA countries.MethodsOfficially nominated national tuberculosis reference laboratories of all EU/EEA countries were asked to provide information on: laboratory routines for detection and identification of NTM, including drug sensitivity testing (DST) methods; data on the number and type of NTM species identified; coverage and completeness of the provided data on NTM; type and number of human specimens tested for NTM; and number of specimens tested for Mycobacterium tuberculosis complex and NTM. This information was summarized and the main results are described.ResultsIn total, 99 different NTM species were identified with M. avium, M. gordonae, M. xenopi , M. intracellulare, and M. fortuitum identified most frequently. Seven percent of the NTM species could not be identified. NTM was cultured from between 0.4-2.0% of the specimens (data from four countries). The laboratories use culturing methods optimised for M. tuberculosis complex. Identification is mainly carried out by a commercial line probe assay supplemented with sequencing. Most laboratories carried out DST for rapid growers and only at the explicit clinical request for slow growers.ConclusionIt is likely that the prevalence of NTM is underestimated because diagnostic procedures are not optimized specifically for NTM and isolates may not be referred to the national reference laboratory for identification. Due to the diagnostic challenges and the need to establish the clinical relevance of NTM, we recommend that countries should concentrate detection and identification in only few laboratories.
Background Human migration caused by political unrest, wars and poverty is a major topic in international health. Infectious diseases like tuberculosis follow their host, with potential impact on both the migrants and the population in the recipient countries. In this study, we evaluate Mycobacterium tuberculosis transmission between the national population and migrants in Denmark. Methods Register study based on IS 6110 -RFLP results from nationwide genotyping of tuberculosis cases during 1992 through 2004. Cases with 100% identical genotypes were defined as clustered and part of a transmission chain. Origin of clusters involving both Danes and migrants was defined as Danish/migrant/uncertain. Subsequently, the proportion of cases likely infected by the "opposite" ethnic group was estimated. Results 4,631 cases were included, representing 99% of culture confirmed cases during 1992 through 2004. Migrants contributed 61.6% of cases. Up to 7.9% (95% CI 7.0-8.9) of migrants were infected by Danes. The corresponding figure was 5.8% (95% CI 4.8-7.0) for Danes. Thus, transmission from Danes to migrants occurred up to 2.5 (95% CI 1.8-3.5) times more frequent than vice versa (OR = 1). A dominant strain, Cluster-2, was almost exclusively found in Danes, particular younger-middle-aged males. Conclusions Transmission between Danes and migrants is limited, and risk of being infected by the "opposite" ethnic group is highest for migrants. TB-control efforts should focus on continues micro-epidemics, e.g. with Cluster-2 in Danes, prevention of reactivation TB in high-risk migrants, and outbreaks in socially marginalized migrants, such as Somalis and Greenlanders. Fears that TB in migrants poses a threat for resident Danes seem exaggerated and unjustified. We believe this to be true for other low incidence countries as well.
Two hundred three freeze-dried strains of Mycobacterium tuberculosis collected during the 1960s were compared with 4102 strains collected during the 1990s, and 14 DNA patterns identified among the "historical strains" were 100% identical to patterns identified among the "recent strains." They were isolated from 41 and 40 patients who had tuberculosis during the 1960s and 1990s, respectively. The patients' mean age differed by >30 years, a finding strongly suggesting that the patients from the 1990s experienced reactivation of M. tuberculosis infection acquired during the 1960s. The half-life of IS6110 DNA patterns during latency was estimated to be 36 years (95% confidence interval, 25-54 years). Thus, this comparison of historical and recent strains yields molecular epidemiologic evidence of M. tuberculosis reactivation spanning decades and suggests that the rate of change of DNA patterns during latency is much longer than that during active disease. This has important implications for the interpretation of clustering, especially for the extent of recent transmission.
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