title: [Antibiotic susceptibility patterns among Shigella sonnei, isolated during three different periods in Región Metropolitana, Chile].
abstract: BACKGROUND
  Shigella sonnei gastroenteritis improves clinically and microbiologically with antibacterial treatment; however choosing a useful drug is a universal challenge because of in vitro susceptibility of S. sonnei frequently evolves to be resistant.
  
  
  OBJECTIVE
  To evaluate in vitro susceptibility of S. sonnei strains isolated from patients attending at the Chilean Región Metropolitana and to know the evolution that resistant patterns of S. sonnei have experienced.
  
  
  METHODS
  In this study, the antimicrobial susceptibility profile of 277 isolates of Shigella sonnei was compared. The analyzed periods of time were: period I (1995-1997) 85 strains; period II (2004-2006) 92 strains and period III (2008-2009) 100 strains, in Santiago, Chile. The method performed to analyze susceptibility patterns was the disc diffusion (Kirby-Bauer).
  
  
  RESULTS
  The strains showed rates of resistance to ampicillin: period I, 85.8%; period II, 53.3%; period III, 100%, trimethoprim/sulfamethoxazole: period I, 50.5%; period, II 46.7%; period III, 100%, chloramphenicol: period I, 36.4%; period II, 12%; period III, 100% and tetracycline: period I, 38.8%; period II, 30.4%; period III, 100%. 98.9% of the strains showed susceptibility to quinolones. Significant differences were observed in patterns of antimicrobial resistance for both individuals and for multidrug resistance (≥ 3 antimicrobials) in the three periods (p < 0.001, χ2 test). Of all resistant strains, 17% were resistant to 1 or 2 antibiotics, while 65.7% showed a pattern of multidrug resistance; 100% of the period III strains presented multidrug resistance.
  
  
  CONCLUSIONS
  These results showed the temporal resistance dynamics of S. sonnei circulating strains in the Chilean Región Metropolitana. Due to the endemic behavior of shigellosis in Chile, it is urgent to maintain permanent surveillance of antimicrobial resistance profiles to improve both prevention and treatment of shigellosis.
authors: Alicia
authors: A
authors: Marcoleta
authors: Cecilia
authors: C
authors: Toro
authors: Valeria
authors: V
authors: Prado
authors: Marcela
authors: M
authors: Serrano
authors: Pilar
authors: P
authors: Fernández
authors: Dona
authors: D
authors: Benadof
authors: Rossana
authors: R
authors: Camponovo
authors: Verónica
authors: V
authors: Campos
authors: Lorena
authors: L
authors: Porte
authors: Juanita
authors: J
authors: Zamorano
authors: Camila
authors: C
authors: Ortega
authors: Belén
authors: B
authors: Urqueta
authors: M Teresa
authors: MT
authors: Ulloa
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002677:Chile; D024901:Drug Resistance, Multiple, Bacterial; D004405:Dysentery, Bacillary / Q000382:microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D012764:Shigella sonnei / Q000187:drug effects* / Q000302:isolation & purification; D013997:Time Factors; D014505:Urban Population
chemical_list: D000900:Anti-Bacterial Agents