title: Trends in antibiotic susceptibility of enteric fever isolates in East London.
abstract: BACKGROUND
  The study sought evidence for changes in the proportions of antibiotic resistant strains among isolates of Salmonella enterica serovar Typhi (S. typhi) and Salmonella enterica serovar Paratyphi (S. paratyphi) between 2005 and 2012.
  
  
  METHODS
  Blood culture isolates of S. typhi and S. paratyphi from patients attending Newham and The Royal London Hospitals were included in the study. The organisms were cultured on selective media and identified by Maldi-ToF, API 20E and serology. Minimum inhibitory concentrations (MICs) of augmentin, chloramphenicol, co-trimoxazole, ceftriaxone, ciprofloxacin and azithromycin were determined by E tests for 194 isolates.
  
  
  RESULTS
  Median MICs of ciprofloxacin and ceftriaxone were stable at 0.5 mg/L and 0.125 mg/L, respectively. Chloramphenicol, azithromycin, co-trimoxazole and augmentin median MICs were 4 mg/L, 8 mg/L, 0.064 mg/L and 0.5 mg/L, respectively. MIC90 values were lower than the resistant breakpoint for ceftriaxone, azithromycin and augmentin, but were >256 mg/L for chloramphenicol, 32 mg/L for co-trimoxazole and 1 mg/L for ciprofloxacin.
  
  
  CONCLUSIONS
  Antibiotic resistance remained stable for enteric fever isolates between 2005 and 2012. The isolates remained susceptible to augmentin, ceftriaxone and azithromycin over this period, but the MIC90 was greater than the resistant breakpoint for chloramphenicol, cotrimoxazole and ciprofloxacin. The implications for clinical practice are that isolates of S. typhi and S. paratyphi from East London remain sensitive to ceftriaxone and azithromycin.
authors.affiliation: Public Health Laboratory London, Public Health England, Barts Health NHS Trust, The Royal London Hospital, Department of Infection, 3rd Floor Pathology & Pharmacy Building, 80 Newark Street, London E1 2ES, UK. Electronic address: jayshree.dave@phe.gov.uk.
authors.forename: Jayshree
authors.initials: J
authors.lastname: Dave
authors.affiliation: Centre of Immunology and Infectious Disease, Blizard Institute, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, UK.
authors.forename: Armine
authors.initials: A
authors.lastname: Sefton
authors.affiliation: Bacteriology Reference Department, Reference Microbiology Services, Colindale London, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: de Pinna
authors.affiliation: Bacteriology Reference Department, Reference Microbiology Services, Colindale London, UK.
authors.forename: Neil
authors.initials: N
authors.lastname: Woodford
authors.affiliation: Public Health Laboratory London, Public Health England, Barts Health NHS Trust, The Royal London Hospital, Department of Infection, 3rd Floor Pathology & Pharmacy Building, 80 Newark Street, London E1 2ES, UK.
authors.forename: Rachel
authors.initials: R
authors.lastname: Meade
authors.affiliation: Public Health Laboratory London, Public Health England, Barts Health NHS Trust, The Royal London Hospital, Department of Infection, 3rd Floor Pathology & Pharmacy Building, 80 Newark Street, London E1 2ES, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Jordan
authors.affiliation: Bacteriology Reference Department, Reference Microbiology Services, Colindale London, UK.
authors.forename: Kathie
authors.initials: K
authors.lastname: Grant
authors.affiliation: Public Health Laboratory London, Public Health England, Barts Health NHS Trust, The Royal London Hospital, Department of Infection, 3rd Floor Pathology & Pharmacy Building, 80 Newark Street, London E1 2ES, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Holliman
authors.affiliation: Division of Infection, The Royal London Hospital, Barts Health NHS Trust, London, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Millar
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D008131:London; D008297:Male; D008826:Microbial Sensitivity Tests; D012479:Salmonella paratyphi C / Q000187:drug effects* / Q000302:isolation & purification; D012485:Salmonella typhi / Q000187:drug effects* / Q000302:isolation & purification; D013997:Time Factors; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology; D014435:Typhoid Fever / Q000382:microbiology*
chemical_list: D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D017963:Azithromycin
keywords: Antimicrobial resistance; Minimum inhibitory concentration (MIC); S. paratyphi; S. typhi