Molecular epidemiology of tuberculosis in England, 1998.
METHODS
England.


OBJECTIVE
To investigate the proportion of tuberculosis (TB) cases attributable to recent transmission and factors associated with clustering.


METHODS
Demographic, clinical and microbiological surveillance data were collated from all new culture-confirmed cases in 1998. Using insertion sequence (IS) 6110 restriction fragment length polymorphism (RFLP) typing, strains were classified as clustered (identical patterns) or unique and risk factors were determined using multivariable logistic regression.


RESULTS
RFLP patterns were available for 2265 of 3713 (61%) cases: 1808 had >or=5 IS6110 copies, while 372 cases were in 152 clusters, giving an estimated proportion due to recent transmission of 12.2%.Pulmonary disease (aOR 1.6; 95%CI 1.1-2.2), previous treatment (aOR 3.7; 2.2-6.5) and homelessness (aOR 5.5; 1.2-24.1) were independent risk factors for clustering. Fourteen per cent of patients of Indian subcontinent origin were clustered compared with 27% of white patients. Many clusters spanned ethnic groups (45%) and geographical regions (47%).


CONCLUSIONS
The calculated proportion of TB cases due to recent transmission is low.Adjusting for missed cases and study duration, it increases to 27.6%. Many cases may arise from reactivation or acquisition outside England. Transmission within England accounted for approximately one in four cases and occurred over wide geographic areas, between ethnic groups and among the homeless. Molecular epidemiology can inform local and national public health action.
Love
J
J
Respiratory Diseases Department, Health Protection Agency (HPA) Centre for Infections, London, UK.
Sonnenberg
P
P
Glynn
J R
JR
Gibson
A
A
Gopaul
K
K
Fang
Z
Z
Le Brun
F
F
Pitman
R
R
Hayward
A C
AC
Innes
J
J
Van den Bosch
C
C
Delpech
V
V
Drobniewski
F
F
Watson
J M
JM
D000293:Adolescent; D000328:Adult; D015373:Bacterial Typing Techniques; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D015897:Comorbidity; D004739:England / Q000453:epidemiology; D005260:Female; D049673:History, 20th Century; D006703:Ill-Housed Persons; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008171:Lung Diseases / Q000453:epidemiology / Q000266:history; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology / Q000266:history*; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000302:isolation & purification; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors; D014376:Tuberculosis / Q000453:epidemiology* / Q000266:history / Q000382:microbiology* / Q000635:transmission; D055815:Young Adult