title: Results from the Survey of Antibiotic Resistance (SOAR) 2009-11 in Vietnam.
abstract: OBJECTIVE
  To investigate the susceptibility of respiratory tract infection pathogens collected between 2009 and 2011 from the SOAR study in Vietnam.
  
  
  METHODS
  MICs were determined using Etest(®) and susceptibility was assessed using CLSI, EUCAST and pharmacokinetic/pharmacodynamic (PK/PD) breakpoints.
  
  
  RESULTS
  Two hundred and eighty-nine Streptococcus pneumoniae and 195 Haemophilus influenzae were collected from 11 centres. Overall, 4.8% of S. pneumoniae were penicillin susceptible (CLSI oral and EUCAST breakpoints). Using CLSI intravenous breakpoints, 86.9% were penicillin susceptible. Susceptibility to high-dose amoxicillin/clavulanic acid (or amoxicillin) using PK/PD breakpoints, cefuroxime (using CLSI or PK/PD breakpoints), cefaclor (CLSI breakpoint) and azithromycin (CLSI breakpoint) was 96.9%, 18.7%, 8% and 4.2%, respectively. Ofloxacin susceptibility was 93.4% by CLSI but 0% by EUCAST. All S. pneumoniae were fully vancomycin susceptible. S. pneumoniae from children were significantly less susceptible to most antimicrobials than those from the elderly. For ofloxacin, however, the reverse was true.Among H. influenzae isolates, 40.5% produced β-lactamase and 13.8% were β-lactamase negative but ampicillin resistant (BLNAR) by CLSI. H. influenzae were highly susceptible (97.4%) in vitro to amoxicillin/clavulanic acid and also to ceftriaxone by CLSI and PK/PD breakpoints but not EUCAST breakpoints. However, BLNAR isolates should be considered clinically resistant, with susceptibility reduced to 84.1%. With EUCAST breakpoints, amoxicillin/clavulanic acid susceptibility was lower, at 63.1%. Azithromycin susceptibility was 79.5% (CLSI).
  
  
  CONCLUSIONS
  Resistance to antibacterials in Vietnam was high, with amoxicillin/clavulanic acid being the most active agent. Ceftriaxone was highly active against H. influenzae while ofloxacin appeared highly active against S. pneumoniae using CLSI but not by EUCAST breakpoints. Ongoing surveillance through SOAR will further assist in understanding susceptibility trends over time.
authors.affiliation: University of Medicine and Pharmacy, 217 Hong Bang Street, Ward 11, District 5, Ho Chi Minh City, Vietnam.
authors.forename: P H
authors.initials: PH
authors.lastname: Van
authors.affiliation: University of Medicine and Pharmacy, 217 Hong Bang Street, Ward 11, District 5, Ho Chi Minh City, Vietnam.
authors.forename: P T
authors.initials: PT
authors.lastname: Binh
authors.affiliation: GlaxoSmithKline Vietnam, Unit 701, 235 Dong Khoi, District 1, Ho Chi Minh City, Vietnam.
authors.forename: N H L
authors.initials: NH
authors.lastname: Minh
authors.affiliation: IHMA Europe Sàrl, 9a route de la Corniche, Epalinges 1066, Switzerland.
authors.forename: I
authors.initials: I
authors.lastname: Morrissey
authors.affiliation: GlaxoSmithKline, 980 Great West Road, Brentford, Middlesex TW8 9GS, UK didem.x.torumkuney@gsk.com.
authors.forename: D
authors.initials: D
authors.lastname: Torumkuney
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D005260:Female; D006192:Haemophilus Infections / Q000453:epidemiology / Q000382:microbiology; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000382:microbiology; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000302:isolation & purification; D014744:Vietnam / Q000453:epidemiology; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents