[Shigella spp infections in children living in the Metropolitan Region, Chile, during summer of 2004-2005].
BACKGROUND
Shigella spp is a frequent cause of diarrhea in children. Antimicrobials decrease the duration of diarrhea and pathogen excretion. However, the increasing resistance limits their therapeutic value.


OBJECTIVE
To study Shigella serotype distribution in the Metropolitan Region in Chile, and its relationship with severity of disease, antimicrobial resistance pattern and clonality.


METHODS
During summer 2004-2005, stool samples from children with diarrhea were collected in Cary Blair transpon medium and cultured. Shigella isolates were serotyped using monoclonal and polyclonal commercial antibodies. In vitro activity of ampicillin, amoxicillin/clavulanic acid, chloramphenicol, cotrimoxazol, nalidixic acid, ciprofloxacin, ceftriaxone and azythromycin was determined by minimal inhibitory concentration (MIC). Clonality was studied by pulsed-field gel electrophoresis (PFGE) using Xbal as restriction enzyme.


RESULTS
One hundred thirty nine Shigella strains were isolated (77 S sonnei and 62 S flexneri). S sonnei and S flexneri 2a serotypes were responsible for 95% of episodes. Children aged 2-4 years, showed a greater incidence of Shigella infections and 77% of episodes were treated on an ambulatory basis. High resistance levels were observed for ampicillin, cotrimoxazole, amoxicillin-clavulanic acid and chloramphenicol (67%, 60%, 56% and 45%, respectively). We found 11 resistance patterns and 61,2% of strains were multiresistant. There were multiple clones without a strict relationship with resistance patterns.


CONCLUSIONS
Shigella infections in Metropolitan Region in Chile are associated to a restricted number of serotypes, representing a clonal expansion associated to different antimicrobial resistant patterns.
Hamilton-West M
Christopher
C
Programa de Microbiología, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.
Prado J
Valeria
V
Hormazábal O
Juan Carlos
JC
Lagos Z
Rosanna
R
Benadof F
Dona
D
Mendoza N
Carmen
C
Elgueta N
Andrea
A
Tapia P
Cecilia
C
C Fuentes D
Marcela
M
Alvarez A
Isabel
I
Hernández E
Mariluz
M
D000208:Acute Disease; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D002677:Chile / Q000453:epidemiology; D003967:Diarrhea / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D004405:Dysentery, Bacillary / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology*; D005243:Feces / Q000382:microbiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008826:Microbial Sensitivity Tests; D012621:Seasons; D012703:Serotyping; D012720:Severity of Illness Index; D012760:Shigella / Q000187:drug effects / Q000235:genetics; D014505:Urban Population
D000900:Anti-Bacterial Agents