title: In vitro activity of azithromycin in Salmonella isolates from Pakistan.
abstract: BACKGROUND
  Enteric fever is caused by Salmonella enterica serovars Typhi and Paratyphi A, B and C. It is a significant public health issue in Pakistan, which is exacerbated by a high level of resistance some isolates display to drugs routinely used in treatment. Azithromycin may be a treatment option for such isolates.
  
  
  METHODS
  We determined the minimum inhibitory concentrations (MICs) of Salmonella Typhi and Paratyphi isolates against azithromycin in an attempt to gauge its feasibility as a therapeutic option. The MICs were also compared with corresponding disc diffusion zone sizes to see if there was consistency between the two tests. We tested 45 Salmonella enterica isolates using E-tests for MIC detection and azithromycin discs with a concentration of 15µg/ml for disc diffusion testing.
  
  
  RESULTS
  Salmonella Typhi, Salmonella Paratyphi A, and Salmonella Paratyphi C isolates demonstrated MICs of 2-12mg/L against azithromycin, suggesting that the antibiotic could be used for therapeutic purposes. For Salmonella Paratyphi B, the MICs were 2-48 mg/L. The higher MIC indicates a need for caution when considering use of azithromycin for Salmonella Paratyphi B infections without first testing for the MIC. There was a close correlation between MICs and zone sizes which was statistically significant.
  
  
  CONCLUSIONS
  Our results indicate azithromycin is a potential therapeutic option for enteric fever. Standardized laboratory testing methods and interpretation for azithromycin against Salmonella enterica would allow laboratories to report upon this antibiotic with confidence.
authors.affiliation: Department of Pathology, Shaukat Khanum Memorial Cancer Hospital and Research Center, Lahore, Pakistan. microreg@msn.com
authors.forename: Farhana
authors.initials: F
authors.lastname: Butt
authors.forename: Faisal
authors.initials: F
authors.lastname: Sultan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D010154:Pakistan; D012482:Salmonella paratyphi A / Q000187:drug effects* / Q000302:isolation & purification; D012485:Salmonella typhi / Q000187:drug effects* / Q000302:isolation & purification; D014435:Typhoid Fever / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D017963:Azithromycin