Mycobacterium avium lymphadenopathy among children, Sweden.

We studied Mycobacterium avium lymphadenopathy in 183 Swedish children (<7 years of age) from 1998 through 2003. Seasonal variation in the frequency of the disease, with a peak in October and a low point in April, suggests cyclic environmental factors. We also found a higher incidence of the disease in children who live close to water.

Molecular epidemiology of drug-resistant tuberculosis in Sweden.

Drug-resistant tuberculosis (TB), including the more severe forms of multidrug- and extensively drug-resistant forms, is an increasing public health concern globally. In Sweden the majority of patients with TB are immigrants from countries with a high incidence of TB including the drug-resistant forms. In this study, the spread of resistant TB in Sweden was investigated by molecular fingerprinting. Isolates resistant to at least one of the drugs, isoniazid, rifampicin, ethambutol or streptomycin, from 400 patients collected between 1994 and 2005, were studied by restriction fragment length polymorphism (RFLP) and by spoligotyping. Thirty-five clusters of patients infected with strains with identical RFLP and spoligotyping patterns (2-96 patients per cluster), comprising a total of 203 patients, were found. One large outbreak of isoniazid resistant tuberculosis was identified, involving 96 patients, mainly from the Horn of Africa. To identify chains of transmission, molecular epidemiological characterization of TB isolates should, if possible, be performed on isolates from all new TB patients.

Molecular and clinical characteristics of invasive group A streptococcal infection in Sweden.

BACKGROUND: The incidence and severity of invasive group A streptococcal infection demonstrate great variability over time, which at least, in part, seems to be related to group A streptococcal type distribution among the human population. METHODS: An enhanced surveillance study of invasive group A streptococcal infection (746 isolates) was performed in Sweden from April 2002 through December 2004. Noninvasive isolates from either the throat or skin (773 isolates) were collected in parallel for comparison. Clinical and epidemiological data were obtained from 88% of patients with invasive disease and were related to isolate characteristics, including T type, emm sequence type, and the presence of 9 superantigen genes, as well as pulsed-field gel electrophoresis pattern comparisons of selected isolates. RESULTS: The annual incidence was 3.0 cases per 100,000 population. Among the patients with invasive disease, 11% developed streptococcal toxic shock syndrome, and 9.5% developed necrotizing fasciitis. The overall case-fatality rate was 14.5%, and 39% of the patients with streptococcal toxic shock syndrome died (P<.001). The T3/13/B3264 cluster accounted for 33% of invasive and 25% of noninvasive isolates. Among this most prevalent type cluster, emm types 89 and 81 dominated. Combined results from pulsed-field gel electrophoresis, emm typing, and superantigen gene profiling identified subgroups within specific emm types that are significantly more prone to cause invasive disease than were other isolates of the same type. CONCLUSIONS: This study revealed a changing epidemiology of invasive group A streptococcal infection in Sweden, with emergence of new emm types that were previously not described. The results also suggest that some clones may be particularly prone to cause invasive disease.

[Resistant tuberculosis is spreading in Sweden. Molecular epidemiological strain identification by "fingerprinting" can make the infection tracing easier]. / Resistent tuberkulos sprids i Sverige. Molekylärepidemiologiska "fingeravtryck" av de infekterande organismerna kan underlätta smittspårning.

Resistance of Mycobacterium tuberculosis to antibiotics is a world wide problem. A study is reported with the aim to analyse the spread of resistant isolates of M tuberculosis complex from patients with tuberculosis in Sweden. The study is based on a sample of 192 M tuberculosis complex isolates from patients with drug resistant tuberculosis during 1994-2000. All isolates resistant to at least one of the drugs streptomycin, isoniazid, ethambutol and rifampicin were included in the study. Restriction fragment length polymorphism (RFLP) was performed, using IS6110 as a probe for hybridisation. Visualised bands were analysed by Gel Compar software. The majority of the isolates were from patients born in high TB prevalence countries. During the years 1996-2000 there was one major cluster generated from 34 isolates. In 1996-1998 there were two isolates per year, in 1999 it increased to 20 isolates, and eight cases in 2000. All strains were resistant to isoniazid. All patients in this cluster were found to be from Africa. In comparing the pattern in the T-base the strains matched with strain BEA-000007341 isolated from a patient in Rwanda. The majority of patients with drug resistant tuberculosis in Sweden are immigrants from countries with high incidence of tuberculosis. Spread of disease to the Swedish born population is uncommon. However, an increasingly prevalent clone of isoniazid resistant tuberculosis was found among African immigrants, mainly living in the Stockholm area.

COPD and the risk of tuberculosis--a population-based cohort study.

BACKGROUND: Both chronic obstructive pulmonary disease (COPD) and tuberculosis (TB) primarily affect the lungs and are major causes of morbidity and mortality worldwide. COPD and TB have common risk factors such as smoking, low socioeconomic status and dysregulation of host defence functions. COPD is a prevalent co-morbid condition, especially in elderly with TB but in contrast to other diseases known to increase the risk of TB, relatively little is known about the specific relationship and impact from COPD on TB-incidence and mortality. METHODS AND FINDINGS: All individuals > or = 40 years of age, discharged with a diagnosis of COPD from Swedish hospitals 1987-2003 were identified in the Swedish Inpatient Register (n = 115,867). Records were linked to the Swedish Tuberculosis Register 1989-2007 and the relative risk of active TB in patients with COPD compared to control subjects randomly selected from the general population (matched for sex, year of birth and county of residence) was estimated using Cox regression. The analyses were stratified by year of birth, sex and county of residence and adjusted for immigration status, socioeconomic status (SES) and inpatient co-morbidities previously known to increase the risk of TB. COPD patients had a three-fold increased hazard ratio (HR) of developing active TB (HR 3.0 (95% confidence interval 2.4 to 4.0)) that was mainly dependent on an increased risk of pulmonary TB. In addition, logistic regression estimates showed that COPD patients who developed active TB had a two-fold increased risk of death from all causes within first year after the TB diagnosis compared to the general population control subjects with TB (OR 2.2, 95% confidence interval 1.2 to 4.1). CONCLUSIONS: This population-based study comprised of a large number of COPD patients shows that these patients have an increased risk of developing active TB compared to the general population. The results raise concerns that the increasing global burden of COPD will increase the incidence of active TB. The underlying contributory factors need to be disentangled in further studies.

Drug resistant Mycobacterium tuberculosis of the Beijing genotype does not spread in Sweden.

BACKGROUND: Drug resistant (DR) and multi-drug resistant (MDR) tuberculosis (TB) is increasing worldwide. In some parts of the world 10% or more of new TB cases are MDR. The Beijing genotype is a distinct genetic lineage of Mycobacterium tuberculosis, which is distributed worldwide, and has caused large outbreaks of MDR-TB. It has been proposed that certain lineages of M. tuberculosis, such as the Beijing lineage, may have specific adaptive advantages. We have investigated the presence and transmission of DR Beijing strains in the Swedish population. METHODOLOGY/PRINCIPAL FINDINGS: All DR M. tuberculosis complex isolates between 1994 and 2008 were studied. Isolates that were of Beijing genotype were investigated for specific resistance mutations and phylogenetic markers. Seventy (13%) of 536 DR strains were of Beijing genotype. The majority of the patients with Beijing strains were foreign born, and their country of origin reflects the countries where the Beijing genotype is most prevalent. Multidrug-resistance was significantly more common in Beijing strains than in non-Beijing strains. There was a correlation between the Beijing genotype and specific resistance mutations in the katG gene, the mabA-inhA-promotor and the rpoB gene. By a combined use of RD deletions, spoligotyping, IS1547, mutT gene polymorphism and Rv3135 gene analysis the Beijing strains could be divided into 11 genomic sublineages. Of the patients with Beijing strains 28 (41%) were found in altogether 10 clusters (2-5 per cluster), as defined by RFLP IS6110, while 52% of the patients with non-Beijing strains were in clusters. By 24 loci MIRU-VNTR 31 (45%) of the patients with Beijing strains were found in altogether 7 clusters (2-11 per cluster). Contact tracing established possible epidemiological linkage between only two patients with Beijing strains. CONCLUSIONS/SIGNIFICANCE: Although extensive outbreaks with non-Beijing TB strains have occurred in Sweden, Beijing strains have not taken hold, in spite of the proximity to high prevalence countries such as Russia and the Baltic countries. The Beijing sublineages so far introduced in Sweden may not be adapted to spread in the Scandinavian population.

Clinical features and incidence of Mycobacterium avium infections in children.

Mycobacterium avium is the most common pathogen in children presenting as non-tuberculous mycobacterial lymphadenitis. In Sweden non-tuberculous mycobacterial infection is a notifiable disease. The goal of our study was to determine the annual incidence of M. avium infection in Swedish children, 1998-2003, and describe clinical features related to age and treatment of children with M. avium lymphadenitis. To do this, we retrospectively analysed patient records of 162 children less than 7 y of age from the entire country with culture-verified M. avium disease. The incidence of M. avium infection in Sweden was lower in 2000-2003 than in 1998-1999. Young children (

Risk and case characteristics of tuberculosis in rheumatoid arthritis associated with tumor necrosis factor antagonists in Sweden.

OBJECTIVE: Because treatment with tumor necrosis factor (TNF) antagonists may increase the risk of tuberculosis (TB), and because knowledge of the risk of TB in rheumatoid arthritis (RA) not treated with biologics is scarce and of uncertain generalizability to low-risk populations, this study sought to determine the risk of TB among Swedish patients with RA. METHODS: Using data from Swedish nationwide and population-based registers and data from an ongoing monitoring program of TNF antagonists, the relative risks of TB in patients with RA (versus the general population) and of TB associated with TNF antagonists (versus RA patients not treated with biologics) were determined by comparing the incidence of hospitalization for TB in 3 RA cohorts and 2 general population cohorts from 1999 to 2001. We also reviewed the characteristics of all reported cases of TB in RA patients treated with TNF antagonists in Sweden and calculated the incidence of TB per type of TNF antagonist between 1999 and 2004. RESULTS: During 1999-2001, RA patients who were not treated with TNF antagonists were at increased risk of TB versus the general population (relative risk 2.0, 95% confidence interval [95% CI] 1.2-3.4). RA patients treated with TNF antagonists had a 4-fold increased risk of TB (relative risk 4.0, 95% CI 1.3-12) versus RA patients not treated with TNF antagonists. The reported TB cases during 1999-2004 in RA patients exposed to TNF antagonists (9 infliximab, 4 etanercept, 2 both) were predominantly pulmonary. TB occurred up to 3 years following the start of treatment. CONCLUSION: Irrespective of whether TNF antagonists are administered, Swedish patients with RA are at increased risk of TB. During 1999-2001, TNF antagonists were associated with an increased risk of TB, up to 4-fold in magnitude. This increased risk may persist over time during treatment and is related to both infliximab and etanercept.