Abstract
Shigella spp are Gram-negative, anaerobic facultative, non-motile, and non-sporulated bacilli of the Enterobacteriaceae family responsible for "Shigellosis" or bacillary dysentery, an important cause of worldwide morbidity and mortality. However, despite this, there are very few epidemiological studies about this bacterium in Brazil. We studied the antibiotic resistance profiles and the clonal structure of 60 Shigella strains (30 S. flexneri and 30 S. sonnei) isolated from shigellosis cases in different cities within the metropolitan area of Campinas, State of São Paulo, Brazil. We used the following well-characterized molecular techniques: enterobacterial repetitive intergenic consensus, repetitive extragenic palindromic, and double-repetitive element-polymerase chain reaction to characterize the bacteria. Also, the antibiotic resistance of the strains was determined by the diffusion disk method. Many strains of S. flexneri and S. sonnei were found to be multi-resistant. S. flexneri strains were resistant to ampicillin in 83.3% of cases, chloramphenicol in 70.0%, streptomycin in 86.7%, sulfamethoxazole in 80.0%, and tetracycline in 80.0%, while a smaller number of strains were resistant to cephalothin (3.3%) and sulfazotrim (10.0%). S. sonnei strains were mainly resistant to sulfamethoxazole (100.0%) and tetracycline (96.7%) and, to a lesser extent, to ampicillin (6.7%) and streptomycin (26.7%). Polymerase chain reaction-based typing supported the existence of specific clones responsible for the shigellosis cases in the different cities and there was evidence of transmission between cities. This clonal structure would probably be the result of selection for virulence and resistance phenotypes. These data indicate that the human sanitary conditions of the cities investigated should be improved.
Highlights
Shigella spp are Gram-negative, facultative anaerobic, non-motile, and non-sporulated bacilli belonging to the Enterobacteriaceae family
We determined the molecular epidemiology of Shigella spp strains (30 S. flexneri and 30 S. sonnei) isolated from shigellosis cases that occurred in different cities in the metropolitan area of Campinas city, State of São Paulo, Southeast Brazil
1.2 million people live in the city of Campinas, a major industrialized, technological, and educational center in the State of São Paulo, Southeast Brazil
Summary
Shigella spp are Gram-negative, facultative anaerobic, non-motile, and non-sporulated bacilli belonging to the Enterobacteriaceae family They are cytochrome-oxidase negative, an important feature that differentiates Enterobacteriaceae bacilli from other fermentative and non-fermentative bacilli. They are able to ferment glucose [1], reduce nitrates to nitrites, and produce acids from carbohydrates. Shigella spp are divided into four groups (or species), namely Shigella flexneri, S. sonnei, S. boydii, and S. dysenteriae They are responsible for shigellosis or bacillary dysentery, a disease that causes high fever, neurological disturbances, and mucus-pyohemorrhagic dysentery [3]. The worldwide burden of this disease has been estimated to be 150 million cases, with 1 million deaths per year in the developing world [5]
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