Epidemiology of tuberculosis in big cities of the European Union and European Economic Area countries.

This cross-sectional survey aimed to examine the epidemiology of tuberculosis (TB) in European Union (EU) and European Economic Area (EEA) cities with populations greater than 500,000. National TB programme managers were asked to provide data on big city population size, total number of notified TB cases in big cities and national notification rate for 2009. A rate ratio was calculated using the big city TB notification rate as a numerator and country TB notification rate, excluding big city TB cases and population, as a denominator. Twenty of the 30 EU/EEA countries had at least one big city. Pooled rate ratios were 2.5, 1.0, and 0.7 in low-, intermediate- and high-incidence countries respectively. In 15 big cities, all in low-incidence countries, rate ratios were twice the national notification rate. These data illustrate the TB epidemiology transition, a situation whereby TB disease concentrates in big cities as national incidence falls, most likely as a result of the higher concentration of risk groups found there. This situation requires targeted interventions and we recommend that big city TB data, including information about patients' risk factors, are collected and analysed systematically, and that successful interventions are shared.

Human immunodeficiency virus associated tuberculosis more often due to recent infection than reactivation of latent infection.

BACKGROUND: It is unclear whether human immunodeficiency virus (HIV) increases the risk of tuberculosis (TB) mainly through reactivation or following recent Mycobacterium tuberculosis (re)infection. Within a DNA fingerprint-defined cluster of TB cases, reactivation cases are assumed to be the source of infection for subsequent secondary cases. As HIV-positive TB cases are less likely to be source cases, equal or higher clustering in HIV-positives would suggest that HIV mainly increases the risk of TB following recent infection. METHODS: A systematic review was conducted to identify all studies on TB clustering and HIV infection in HIV-endemic populations. Available individual patient data from eligible studies were pooled to analyse the association between clustering and HIV. RESULTS: Of seven eligible studies, six contributed individual patient data on 2116 patients. Clustering was as, or more, likely in the HIV-positive population, both overall (summary OR 1.26, 95%CI 1.0-1.5), and within age groups (OR 1.50, 95%CI 0.9-2.3; OR 1.00, 95%CI 0.8-1.3 and OR 2.57, 95%CI 1.4-5.7) for ages 15-25, 26-50 and >50 years, respectively. CONCLUSIONS: Our results suggest that HIV infection mainly increases the risk of TB following recent M. tuberculosis transmission, and that TB control measures in HIV-endemic settings should therefore focus on controlling M. tuberculosis transmission rather than treating individuals with latent M. tuberculosis infection.

[Principles of epidemic emergency preparedness planning: the example of the German Influenza Pandemic Preparedness Plan]. / Prinzipien und Aspekte der Seuchenalarmplanung am Beispiel der Influenzapandemieplanung.

Despite significant medical progress, recent events have shown that infectious diseases have not lost significance. Indeed, the threat of worldwide epidemics has increased. Due to their high infectious ness and rapid person-to-person transmissibility, the emergence of new influenza viruses with pandemic potential poses an especially alarming situation in this regard. The world population would be "immunologically naïve" to a new pandemic virus, permitting explosive spread of the disease. During the last century, three influenza pandemics have demonstrated that this is not merely a hypothetical risk. Currently it is feared that the possible human adaptation of avian influenza viruses that have recently become endemic in birds in Southeast Asia could result in a new pandemic strain. With the publication of the German Influenza Pandemic Preparedness Plan, preparation for this potential threat has reached an important stage in Germany. The implementation of the plan, which includes measures that go beyond the scope of public health, must now proceed swiftly. The long-term goal of pandemic preparedness planning is to be better equipped to deal with potential health threats in general, in particular those ensuing from the emergence of new infectious diseases under conditions of a growing global network.

[Latent tuberculosis infection: recommendations for preventive therapy in adults in Germany]. / Latente tuberkulöse Infektion: Empfehlungen zur präventiven Therapie bei Erwachsenen in Deutschland. Deutsches Zentralkomitee zur Bekämpfung der Tuberkulose.

The immunologic mechanisms of latent tuberculosis (TB) infection are complex and hitherto not completely understood. The lifelong risk of an immunocompetent individual of developing active TB after infection with M. tuberculosis is 5-10 % and highest during the first two years after infection. Various factors may considerably increase the risk of developing active TB, e. g., immunosuppressive disease or immunosuppressive medication. However, the development of active TB may be avoided by preventive chemotherapy, the therapy of choice being isoniazid over a 9-month period. Alternative treatment regimens may be indicated in special cases, but it must be borne in mind that the efficacy of these regimens has not been studied sufficiently while they seem to be less well tolerated than isoniazid monotherapy. The tuberculin skin test is still the only sufficiently documented method to detect latent infection with M. tuberculosis which is also suitable for routine application. This test today should be performed exclusively as described by Mendel and Mantoux. Its sensitivity and specificity depend on the prevalence of tuberculosis infection. It should therefore be restricted to individuals at increased risk of latent TB infection. When interpreting the tuberculin skin test, it is necessary to know whether an individual belongs to one of the defined risk groups or has an elevated risk of developing active TB. Among the risk groups are individuals who may have been infected recently with M. tuberculosis (contacts of contagious TB patients) or in whom other factors increase their risk of developing active TB. The indication for chemotherapy for latent TB infection must be based on a careful individual risk-benefit analysis and, besides patient compliance, requires full information of the patient and careful monitoring during therapy. Before initiating treatment, active TB must always be excluded by the proven methods.

[Leprosy - An overview from a pediatric perspective]. / Lepra - Ein Uberblick aus pädiatrischer Sicht.

Worldwide tourism is an increasing industry. One result of this phenomenon is the occurrence of imported infectious diseases, as recently observed even in Germany. Leprosy ranks high among dreaded infectious diseases from tropical and subtropical countries. It remains a major health threat despite marked improvements in diagnosis and therapy. This was achieved by a better understanding of bacteriological and immunological mechanisms over the past decades, resulting in a decline of Leprosy's incidence.

Postoperative Mycobacterium avium osteomyelitis confirmed by polymerase chain reaction.

UNLABELLED: An 18-year-old male with Escobar syndrome developed Mycobacterium avium osteomyelitis after corrective osteotomy. After three surgical interventions the infection reappeared a fourth time. Repeated attempts at microbiological diagnosis of the granulomatous lesions by microscopy and culture for conventional bacteria and Mycobacteria did not reveal any organism. The diagnosis of Mycobacterium avium finally was achieved by polymerase chain reaction. Extensive immunological work-up did not reveal signs of immunodeficiency. The patient was treated successfully by a combined surgical and chemotherapeutic approach consisting of clarithromycin, ethambutol and ciprofloxacin. CONCLUSION: Polymerase chain reaction may be especially useful for clinical situations with a low bacterial load, especially for fastidious and slow growing pathogens like Mycobacteria. In our patient a combination of surgical therapy with a triple regimen containing clarithromycin proved successful for treatment of a localised infection with M. avium in a supposedly immunocompetent host.

Transmission dynamics of tuberculosis in a high-incidence country: prospective analysis by PCR DNA fingerprinting.

We have prospectively analyzed the DNA fingerprints of Mycobacterium tuberculosis strains from a random sample of patients with newly diagnosed tuberculosis in Windhoek, Namibia. Strains from 263 smear-positive patients in whom tuberculosis was diagnosed during 1 year were evaluated, and the results were correlated with selected epidemiological and clinical data. A total of 163 different IS6110 fingerprint patterns were observed among the 263 isolates. Isolates from a high percentage of patients (47%) were found in 29 separate clusters, with a cluster defined as isolates with 100% matching patterns. The largest cluster included isolates from 39 patients. One predominant strain of M. tuberculosis caused 15% of cases of smear-positive pulmonary tuberculosis in Windhoek. That strain was also prevalent in the north of the country, suggesting that in contrast to other African countries with isolates with high levels of diversity in their DNA fingerprint patterns, only a restricted number of different strains significantly contribute to the tuberculosis problem in Namibia.

Comparison of methods based on different molecular epidemiological markers for typing of Mycobacterium tuberculosis complex strains: interlaboratory study of discriminatory power and reproducibility.

In this study, the currently known typing methods for Mycobacterium tuberculosis isolates were evaluated with regard to reproducibility, discrimination, and specificity. Therefore, 90 M. tuberculosis complex strains, originating from 38 countries, were tested in five restriction fragment length polymorphism (RFLP) typing methods and in seven PCR-based assays. In all methods, one or more repetitive DNA elements were targeted. The strain typing and the DNA fingerprint analysis were performed in the laboratory most experienced in the respective method. To examine intralaboratory reproducibility, blinded duplicate samples were included. The specificities of the various methods were tested by inclusion of 10 non-M. tuberculosis complex strains. All five RFLP typing methods were highly reproducible. The reliability of the PCR-based methods was highest for the mixed-linker PCR, followed by variable numbers of tandem repeat (VNTR) typing and spoligotyping. In contrast, the double repetitive element PCR (DRE-PCR), IS6110 inverse PCR, IS6110 ampliprinting, and arbitrarily primed PCR (APPCR) typing were found to be poorly reproducible. The 90 strains were best discriminated by IS6110 RFLP typing, yielding 84 different banding patterns, followed by mixed-linker PCR (81 patterns), APPCR (71 patterns), RFLP using the polymorphic GC-rich sequence as a probe (70 patterns), DRE-PCR (63 patterns), spoligotyping (61 patterns), and VNTR typing (56 patterns). We conclude that for epidemiological investigations, strain differentiation by IS6110 RFLP or mixed-linker PCR are the methods of choice. A strong association was found between the results of different genetic markers, indicating a clonal population structure of M. tuberculosis strains. Several separate genotype families within the M. tuberculosis complex could be recognized on the basis of the genetic markers used.

Universal pattern of RpoB gene mutations among multidrug-resistant isolates of Mycobacterium tuberculosis complex from Africa.

SETTING: Multidrug-resistant tuberculosis (MDR-TB) presents an increasing burden in Southern Africa. Rapid diagnostic tests for drug resistance to rifampicin have been developed based on mutation analysis of the rpoB gene. However, geographic differences of underlying mutations have recently been suggested. OBJECTIVE: Drug-resistant strains of Mycobacterium tuberculosis complex from Africa were analysed for geographic differences in frequency and location of rpoB mutations. DESIGN: A random sample of rifampicin-resistant strains was collected from 87 patients with pulmonary MDR-TB treated in 12 hospitals from six different regions of South Africa. In addition, 18 isolates of M. tuberculosis complex from Namibia, Sierra Leone, and Uganda, including 13 isolates of M. africanum, were analyzed. Point mutations were detected by direct sequence analysis of the rpoB gene. RESULTS: Missense mutations were identified for 91 isolates (87%). Double mutations were present in eight (8%) MDR-TB isolates, two of which carried one mutation outside a previously described diagnostic region. We found no geographic differences regarding the frequency and pattern of single rpoB gene mutations. CONCLUSION: Our results confirm that molecular genetic analysis of rifampicin resistance based on a core region within the rpoB gene is universally applicable to strains of M. tuberculosis complex from different geographic regions.

Identification of contaminating fungal DNA sequences in Zymolyase.

When different preparations of Zymolyase were included in the pretreatment protocol of a panfungal PCR assay using a primer system for the 18S rRNA gene, an amplification product occurred in negative controls. The amplified fragment showed 100.0% sequence identity to the Saccharomyces sensu stricto complex and Kluyveromyces lodderae. Lyticase, lysing enzymes, and proteinase K appeared to be free from fungal DNA.

Preoperative diagnosis of Mycobacterium avium lymphadenitis in two immunocompetent children by polymerase chain reaction of gastric aspirates.

BACKGROUND: Analysis of gastric aspirates is a routine procedure for detection of Mycobacterium tuberculosis in pediatric pulmonary tuberculosis. However, identification of nontuberculous mycobacteria in gastric aspirates of immunocompetent children is not thought to be clinically significant. METHODS: A PCR method was devised for the detection of M. avium in clinical specimens. The method is based on the amplification of a M. avium-specific DNA fragment present in the 3'-end of the repetitive element IS1245. Surgically removed lymphatic tissue was analyzed prospectively by microscopy, culture and PCR in 13 children admitted to our hospital with suspected mycobacterial lymphadenitis. In 4 of these children 1 to 4 gastric aspirates were obtained before surgical treatment and submitted to the same analysis. RESULTS: We report the detection of M. avium in the gastric aspirates of two children with cervical lymphadenitis before surgical intervention by a novel PCR method. The subsequently surgically removed lymph nodes were also positive by PCR and culture. In one child cultures of both sources grew M. avium. The isolates could be identified as the same strain by DNA fingerprinting. The PCR assay was almost twice as sensitive as culture in detecting M. avium. CONCLUSIONS: Our findings suggest the possibility for noninvasive diagnosis of cervical lymphadenitis caused by nontuberculous mycobacteria before surgery. In addition detection of M. avium in gastric aspirates without evidence of fistula formation provides new insights into the pathogenesis of mycobacterial infection and disease in immunocompetent children.

[Molecular biology methods in epidemiology of tuberculosis]. / Molekularbiologische Methoden in der Epidemiologie der Tuberkulose.

The spread of tuberculosis often remains undetected and development of disease may occur years after the primary infection. However, tracing chains of transmission is an important task for prevention of new cases, especially for multi-drug-resistant tuberculosis. Today, molecular typing methods have become an important tool for identification and confirmation of epidemiological links between tuberculosis patients in an outbreak situation. Differentiation between strains of Mycobacterium tuberculosis also allows to decide between reactivation because of treatment failure and superinfection. A growing number of typing methods have been developed that differ mainly in their reproducibility and the ability to differentiate between isolates closely related at the molecular level. Based on further standardisation and automation, molecular typing techniques can provide pertinent information for tuberculosis control.

DNA fingerprinting of Mycobacterium tuberculosis complex culture isolates collected in Brazil and spotted onto filter paper.

The usefulness of filter paper for preservation of bacterial cells was shown by mixed-linker DNA fingerprint analysis of Mycobacterium tuberculosis isolates from 77 Brazilian patients. DNA fingerprints of samples spotted onto filter paper and conventional culture material were identical. Thus, filter paper specimens analyzed by an amplification-based typing method provide a new resource for epidemiological studies of infectious diseases.

A new agent of mycobacterial lymphadenitis in children: Mycobacterium heidelbergense sp. nov.

Nontuberculous mycobacterial lymphadenitis presents an increasing clinical problem in immunocompetent young children. A slowly growing, nonphotochromogenic mycobacterium was recovered twice (isolates 2553/91 and 2554/91) from the lymphatic tissue of a child with recurrent cervical lymphadenitis. It could be differentiated biochemically from described Mycobacterium species, although it most closely resembled Mycobacterium malmoense by thin-layer chromatography and high-performance liquid chromatography of mycolic acids. A striking characteristic of the isolate was its high degree of susceptibility to antituberculous drugs in vitro, including isoniazid. Direct determination of the 16S rRNA gene sequence revealed a unique sequence and positioned the strain phylogenetically on a branch separate from M. malmoense within a group of slowly growing mycobacteria that show a high degree of similarity to M. simiae at the 16S rRNA gene level. Despite 99.6% sequence identity with M. simiae at the 16S rRNA gene level, DNA-DNA hybridization studies (hydroxyapatite method) demonstrated DNA relatedness of less than 40%. We conclude that this organism is a new species for which we propose the name M. heidelbergense. A culture of the type strain, strain 2554/91, has been deposited in the American Type Culture Collection as strain ATCC 51253.

Molecular analysis of katG gene mutations in strains of Mycobacterium tuberculosis complex from Africa.

A sample of 124 isoniazid (INH)-resistant and 88 susceptible strains of Mycobacterium tuberculosis complex from south, central, and west Africa was analyzed by direct sequence analysis and PCR-restriction fragment length polymorphism analysis of their catalase-peroxidase (katG) genes. Point mutations at codon 315 were found in the genomes of 64% of INH-resistant strains, but no complete deletions were identified. Mutations at codon 463 were independent of INH resistance and were linked to the geographic origins of the strains.

Comparison of DNA fingerprint patterns of isolates of Mycobacterium africanum from east and west Africa.

Mycobacterium africanum is a pathogen found in tuberculosis patients in certain parts of Africa and is a member of the Mycobacterium tuberculosis complex. Biochemically, strains of M. africanum exhibit a high degree of variability, with some tendency to cluster according to their geographical origin. To investigate whether this phenotypic variability is reflected at the genetic level, we performed DNA fingerprint analysis of strains isolated from patients with pulmonary tuberculosis in Uganda and Sierra Leone. IS6110 DNA fingerprinting was carried out by the mixed-linker PCR method. A total of 138 strains of M. africanum were analyzed: 42 isolates from Uganda and 96 isolates from Sierra Leone. With few exceptions, the resulting DNA fingerprint patterns grouped together according to their country of origin. A striking lack of variability of DNA fingerprints was found for strains from Sierra Leone, where 70 of 96 isolates (61.5%) fell into clusters. The two largest clusters accounted for 41.7% of all isolates and differed by only one band, as confirmed by standard DNA fingerprinting. In contrast, only two clusters (7.1%) with two and three isolates, respectively, were found for M. africanum isolates collected in Uganda, and three of the DNA fingerprints contained fewer than seven bands. Strains of M. tuberculosis collected and processed during the same time period were highly variable in both countries. Our results support the concept of geographically defined subtypes of M. africanum. In addition, they demonstrate that natural geographic differences in the variability of IS6110 DNA fingerprints within the M. tuberculosis complex must be considered if this technique is used for epidemiologic studies.

Retirement migration decision making: life course mobility, sequencing of events, social ties and alternatives.

The authors analyze post-retirement migration trends and the decision-making processes that determine this behavior. "We will deal here with issues which indicate not only who among pre-retirees are likely to relocate upon retirement, but also when in the pre-retirement phase decisions about the move are made and the role which individuals' ties to specific places and the characteristics of places themselves play in the decision-making process." Data are from a pilot study conducted in North Carolina in 1992.