The serogroup distribution and antimicrobial susceptibility patterns of
Shigella isolates obtained from stool specimens of persons with acute
diarrhoea in community-based studies from southern Trinidad during
1997-2006 were reviewed. Of the 5,187 stool specimens, 392 (8%) were
positive for Shigella organisms. From these 392 isolates, 88.8% were
recovered from children aged >0-10 year(s). Shigella sonnei was
the most frequently-isolated serogroup (75%), followed by S. flexneri
(19%), S. boydii (4.1%), and S. dysenteriae (1.8%). S. flexneri was the
major isolate among the >20-30 years age-group. The most common drug
resistance among all age-groups was to ampicillin. All strains of S.
flexneri, S. boydii, and S. dysenteriae were fully susceptible to
aztreonam, gentamicin, and ciprofloxacin. S. sonnei, the most common
species isolated, showed resistance to all antibiotics tested. The data
showed that, throughout the study period, the resistance to
commonly-used drugs was relatively low. Since resistance to several
drugs seems to be emerging, continuous monitoring of resistance
patterns is mandatory for the appropriate selection of empiric
antimicrobial drugs in the therapy of suspected cases of shigellosis