A total of 296
Shigella
spp. were received from State Public Health Laboratories, during the period from 1999 to 2004, by National Reference Laboratory for Cholera and Enteric Diseases (NRLCED) - IOC/Fiocruz, Rio de Janeiro, Brazil. The frequency of
Shigella spp. was:
S. flexneri (52.7%),
S. sonnei (44.2%),
S. boydii (2.3%), and
S. dysenteriae (0.6%). The most frequent
S. flexneri serovars were 2a and 1b. The highest incidence rates of
Shigella isolation were observed in the Southeast (39%) and Northeast (34%) regions and the lowest rate in the South (3%) of Brazil. Strains were further analyzed for antimicrobial susceptibility by disk diffusion method as part of a surveillance program on antimicrobial resistance. The highest rates of antimicrobial resistance were to trimethoprim-sulfamethozaxole (90%), tetracycline (88%), ampicillin (56%), and chloramphenicol (35%). The patterns of antimicrobial resistance among
Shigella isolates pose a major difficulty in the determination of an appropriate drug for shigellosis treatment. Continuous monitoring of antimicrobial susceptibilities of
Shigella spp. through a surveillance system is thus essential for effective therapy and control measures against shigellosis.
