Molecular epidemiology of Mycobacterium tuberculosis clinical isolates in Southwest Ireland.

Tuberculosis has had significant effects on Ireland over the past two centuries, causing persistently higher morbidity and mortality than in neighbouring countries until the last decade. This study describes the results of genotyping and drug susceptibility testing of 171 strains of Mycobacterium tuberculosis complex isolated between January 2004 and December 2006 in a region of Ireland centred on the city of Cork. Spoligotype comparisons were made with the SpolDB4 database and clustered 130 strains in 23 groups, forty-one strains showed unique Spoligotyping patterns. The commonest spoligotypes detected were ST0137 (X2) (16.9%), and ST0351 (15.8%) ('U' clade). The major spoligotype clades were X (26.2%), U (19.3%), T (15.2%), Beijing (5.9%), Haarlem (4.7%), LAM (4.1%), BOVIS (1.75%), with 12.9% unassigned strains. A 24-locus VNTR genotyping produced 15 clusters containing 49 isolates, with high discrimination index (HGDI>0.99). A combination of Spoligotyping and VNTR reduced the number of clustered isolates to 47 in 15 clusters (27.5%). This study identified ST351 as common among Irish nationals, and found a low rate of drug resistance with little evidence of transmission of drug resistant strains. Strain clustering was significantly associated with age under 55 years and Irish nationality. Only strains of Euro-American lineage formed clusters. Molecular typing did not completely coincide with the results of contact investigations.

Mycobacterium bovis strains causing smear-positive human tuberculosis, Southwest Ireland.

Mycobacterium bovis caused 3% of human tuberculosis cases in southwest Ireland during 1998-2006. Of 11 M. bovis strains genotyped, 9 belonged to common animal spoligotypes. Seven strains were from sputum and potential sources of human-centered disease transmission. Ten-locus variable-number tandem repeat typing gave unique strain profiles and would detect disease outbreaks.

Drug-resistant tuberculosis, clinical virulence, and the dominance of the Beijing strain family in Russia.

CONTEXT: Tuberculosis and multidrug-resistant tuberculosis is a serious public health problem in Russia. OBJECTIVE: To address the extent of "Beijing strain" transmission in the prison/civil sectors and the association of drug resistance, clinical, and social factors with the Beijing genotype. DESIGN AND SETTING: Cross-sectional population-based molecular epidemiological study of all civilian and penitentiary tuberculosis facilities in the Samara region, Russia. PATIENTS: Consecutively recruited patients with bacteriologically proven tuberculosis (n = 880). MAIN OUTCOME MEASURE: Proportion of Beijing strains and association with drug resistance, human immunodeficiency virus infection, imprisonment, radiological, clinical, and other social factors. RESULTS: Beijing-family strains (identified by spoligotyping and composed of 2 main types by mycobacterial interspersed repetitive unit analysis) were predominant: 586/880 (66.6%; 95% confidence interval [CI], 63.4%-69.7%) with a significantly higher prevalence in the prison population (rate ratio [RR], 1.3; 95% CI, 1.2-1.5) and those aged younger than 35 years (RR, 1.2; 95% CI, 1.0-1.3). Comparable proportions were co-infected with the human immunodeficiency virus ( approximately 10%), concurrent hepatitis B and C (21.6%), drank alcohol ( approximately 90%), smoked ( approximately 90%), and had a similar sexual history. Drug resistance was nearly 2-fold higher in patients infected with Beijing strains compared with non-Beijing strains: multidrug resistance (RR, 2.4; 95% CI, 1.9-3.0), for isoniazid (RR, 1.8; 95% CI, 1.5-2.1), for rifampicin (RR, 2.2; 95% CI, 1.7-2.7), for streptomycin (RR, 1.9; 95% CI, 1.5-2.3), and for ethambutol (RR, 2.2; 95% CI, 1.6-3.2). Univariate analysis demonstrated that male sex (odds ratio [OR], 1.5; 95% CI, 1.1-1.9), advanced radiological abnormalities (OR, 3.3; 95% CI, 1.3-8.4), homelessness (OR, 5.6; 95% CI, 1.1-6.3), and previous imprisonment (OR, 2.0; 95% CI, 1.5-2.7) were strongly associated with Beijing-strain family disease. Multivariate analysis supported previous imprisonment to be a risk factor (OR, 2.0; 95% CI, 1.4-3.3) and night sweats to be less associated (OR 0.7; 95% CI, 0.5-1.0) with Beijing-strain disease. CONCLUSIONS: Drug resistance and previous imprisonment but not human immunodeficiency virus co-infection were significantly associated with Beijing-strain infection. There was evidence that Beijing isolates caused radiologically more advanced disease.