title: Surveillance and correlation of antibiotic prescription and resistance of Gram-negative bacteria in Singaporean hospitals.
abstract: A surveillance study was performed in four Singapore public hospitals from 2006 to 2008 to determine the correlation between antibiotic prescription and Gram-negative bacterial antimicrobial resistance. Targeted organisms included ceftriaxone- and ciprofloxacin-resistant Escherichia coli and Klebsiella pneumoniae, as well as imipenem-resistant Pseudomonas aeruginosa and Acinetobacter spp. Antibiotic prescription data were collated in the WHO anatomical therapeutic chemical (ATC)/defined daily dose (DDD) format, while antibiotic resistance was expressed as incidence density adjusted for total inpatient-days every quarter. Individual trends were determined by linear regression, while possible associations between antibiotic prescription and resistance were evaluated via cross-correlation analysis. Results over 3 years indicated significantly rising incidence densities of ceftriaxone- and ciprofloxacin-resistant E. coli and imipenem-resistant Acinetobacter spp. (blood isolates only). Antimicrobial-resistant Klebsiella pneumoniae rates declined. The prescription rates of piperacillin-tazobactam, ertapenem, meropenem, ciprofloxacin, and levofloxacin increased significantly, while imipenem and moxifloxacin prescription decreased. Cross-correlation analysis demonstrated possible associations between prescription of fluoroquinolones and ciprofloxacin-resistant E. coli (R(2) = 0.46), fluoroquinolones and ceftriaxone-resistant E. coli (R(2) = 0.47), and carbapenems and imipenem-resistant Acinetobacter spp. (R(2) = 0.48), all at zero time lag. Changes in meropenem prescription were associated with a similar trend in imipenem-resistant Acinetobacter blood isolates after a 3-month time lag. No correlation was found between cephalosporin use and resistance. In conclusion, our data demonstrated correlation between prescription of and Gram-negative bacterial resistance to several, but not all, key antimicrobial agents in Singapore hospitals. In areas where Gram-negative bacterial resistance is endemic and prescription of broad-spectrum antimicrobial agents is high, factors other than antimicrobial usage may be equally important in maintaining high resistance rates.
authors.affiliation: Department of Medicine, National University Hospital, 5 Lower Kent Ridge Road, Singapore 119074, Singapore. liyang_hsu@yahoo.com
authors.forename: Li-Yang
authors.initials: LY
authors.lastname: Hsu
authors.forename: Thean-Yen
authors.initials: TY
authors.lastname: Tan
authors.forename: Vincent H
authors.initials: VH
authors.lastname: Tam
authors.forename: Andrea
authors.initials: A
authors.lastname: Kwa
authors.forename: Dale Andrew
authors.initials: DA
authors.lastname: Fisher
authors.forename: Tse-Hsien
authors.initials: TH
authors.lastname: Koh
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D024881:Drug Resistance, Bacterial; D004363:Drug Utilization / Q000706:statistics & numerical data*; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D006779:Hospitals, Public / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008826:Microbial Sensitivity Tests; D012846:Singapore
chemical_list: D000900:Anti-Bacterial Agents