Previous Article | Next Article ![]()
Journal of Clinical Microbiology, Jul 1996, 1701-1707, Vol 34, No. 7
AE Fica, S Prat-Miranda, A Fernandez-Ricci, K D'Ottone and FC Cabello
From 1977 to 1986, Chile experienced an important typhoid fever epidemic,
despite statistics that indicated apparently improving levels of sanitation
of drinking water and sewage disposal. The lack of antibiotic resistance
among the Salmonella typhi strains isolated during this period, the mild
clinical presentation of the disease, and the initially low level of
efficacy of the S. typhi Ty21a vaccine in the population exposed to the
epidemic suggested that this epidemic might have resulted from the
dissemination of S. typhi strains with unique characteristics. To
investigate this hypothesis, we used conventional methods (bacteriophage
typing and biotyping) and molecular methods (restriction fragment length
polymorphism analysis, ribotyping, IS200 typing, and PCR amplification of
the fliC-d gene) to study a population of 149 S. typhi isolates during
1977, 1981, and 1990, the years that included periods with low (when the
disease was endemic) and high (when the disease was epidemic) morbidities.
Our results indicate that these S. typhi isolates in Chile represent a
number of highly diverse variants of the clone of S. typhi with a worldwide
distribution described by Selander et al. (R. K. Selander, P. Beltran, N.H.
Smith, R. Helmuth, F.A. Rubin, D.J. Kopecko, K. Ferris, B.D. Tall, A.
Cravioto, and J.M. Musser, Infect. Immun. 58:2262-2275, 1990). For example,
we detected 26 PstI and 10 ClaI ribotypes among 47 and 16 S. typhi strains
belonging to this clone, respectively. These results suggest that the
Chilean epidemic was probably produced by multiple sources of infection
because of deficient sanitary conditions. These findings illustrate the
usefulness of molecular methods for characterizing the potential causes of
the typhoid epidemics and the possible routes of transmission of S. typhi
strains in typhoid epidemics.
Copyright © 1996 by the American Society for Microbiology. All rights reserved.
Epidemic typhoid in Chile: analysis by molecular and conventional methods of Salmonella typhi strain diversity in epidemic (1977 and 1981) and nonepidemic (1990) years
Department of Microbiology and Immunology, New York Medical College, Valhalla 10595, USA.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»