title: Trends in antimicrobial resistance in Shigella species in Karachi, Pakistan.
abstract: BACKGROUND
  Shigellosis is a common cause of morbidity, especially in the very young and old, in developing countries. The disease is treated with antibiotics. Surveillance of antimicrobial resistance trends is essential owing to the global emergence of antimicrobial resistance.
  
  
  METHODS
  The study involved 1,573 isolates of Shigella species (1996-2007) that were analyzed for trends in antimicrobial resistance.
  
  
  RESULTS
  The majority of the specimens (1046; 66.5%) were from the pediatric population, and of these 887 (84.8%) were under 5 years of age (p = 0.001). S. flexineri was the most frequent species (54.5%) isolated. Isolation of S. sonnei increased from 15.4 % (1996) to 39% (2007) (p = 0.001). Although none of the isolates was found sensitive to all the antibiotics tested, 58% (n =9 07) were resistant to ampicillin and 85% (n = 1,338) were resistant to trimethoprim-sulfamethoxazole (TMP-SMX). Out of a total of 198 (12.6%) nalidixic acid resistant isolates, 6 (3.0%) were also resistant to ofloxacin. Overall 1.7 % of isolates were resistant to ofloxacin, 2.4% to ceftriaxone and 2.3% were resistant to combination of ampicillin, nalidixic acid and TMP-SMX.
  
  
  CONCLUSIONS
  Ofloxacin is still an effective drug for treatment of acute shigellosis in Pakistan. Emergence of resistance to ceftriaxone in Shigella may have grave implications in treatment of severe shigellosis in very young patients.
authors.affiliation: Department of Pathology and Microbiology, Aga Khan University Hospital, Stadium Road, PO Box 3500, Karachi 74800, Sindh, Pakistan. erum.khan@aku.edu
authors.forename: Erum
authors.initials: E
authors.lastname: Khan
authors.forename: Kausar
authors.initials: K
authors.lastname: Jabeen
authors.forename: Muslima
authors.initials: M
authors.lastname: Ejaz
authors.forename: Jaweriah
authors.initials: J
authors.lastname: Siddiqui
authors.forename: Muhammad Farrukh
authors.initials: MF
authors.lastname: Shezad
authors.forename: Afia
authors.initials: A
authors.lastname: Zafar
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000667:Ampicillin / Q000008:administration & dosage; D000890:Anti-Infective Agents / Q000008:administration & dosage; D002443:Ceftriaxone / Q000008:administration & dosage; D002648:Child; D002675:Child, Preschool; D024901:Drug Resistance, Multiple, Bacterial; D004359:Drug Therapy, Combination; D004405:Dysentery, Bacillary / Q000188:drug therapy* / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D007223:Infant; D008826:Microbial Sensitivity Tests; D009268:Nalidixic Acid / Q000008:administration & dosage; D015242:Ofloxacin / Q000008:administration & dosage; D010154:Pakistan / Q000453:epidemiology; D012760:Shigella / Q000187:drug effects / Q000302:isolation & purification; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000008:administration & dosage
chemical_list: D000890:Anti-Infective Agents; D009268:Nalidixic Acid; D002443:Ceftriaxone; D000667:Ampicillin; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D015242:Ofloxacin