Clustering of tuberculosis among senegalese immigrants in Italy.
OBJECTIVE
To study clustered Mycobacterium tuberculosis isolates as an indicator of recent TB transmission in a small urban setting in Italy, and to determine associated risk factors.


METHODS
M. tuberculosis strains isolated between 1991 and 1997 were characterised by IS6110 restriction fragment length polymorphism (RFLP) analysis.


RESULTS
One hundred and ninety-five isolates were available for RFLP analysis, which revealed 163 different patterns. Available cases were represented by 137 Italians (70%), 32 Senegalese (17%), and 26 other foreign-born cases (13%). A unique fingerprint pattern was found in 143 cases (73.3%), while 52 strains (26.7%) were grouped into 20 clusters. Nineteen cases (10%) were resident in the same quarter of Brescia with a high density of Senegalese immigrants (Area A). An increased probability of yielding clustered M. tuberculosis strains was associated with residence in Area A (OR 3.87, 95%CI 1.42-10.56; P = 0.02) and being Senegalese (OR = 5.96, 95%CI 1.48-23.97; P = 0.005). In the logistic regression analysis, being Senegalese was independently associated with yielding a clustered M. tuberculosis strain.


CONCLUSIONS
Our results demonstrate a clustering of TB cases among Senegalese immigrants and suggest that RFLP analysis may be used to identify geographical areas where efforts can be targeted to interrupt TB transmission.
Matteelli
A
A
Department of Infectious Diseases, Institute of Infectious Diseases, Brescia, Italy. amatteelli@bsnet.it
Gori
A
A
Pinsi
G
G
El-Hamad
I
I
Bombana
E
E
Mastaglia
F
F
Degli Esposti
A
A
Bandera
A
A
Tedoldi
S
S
Casalini
C
C
Scolari
C
C
Carvalho
A C C
AC
Carosi
G
G
D000328:Adult; D000368:Aged; D004641:Emigration and Immigration; D006801:Humans; D007558:Italy; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009161:Mycobacterium / Q000302:isolation & purification*; D010865:Pilot Projects; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors; D014376:Tuberculosis / Q000382:microbiology* / Q000635:transmission*