title: The effects of group 1 versus group 2 carbapenems on imipenem-resistant Pseudomonas aeruginosa: an ecological study.
abstract: Use of the group 2 carbapenems, imipenem and meropenem, may lead to emergence of Pseudomonas aeruginosa resistance. The group 1 carbapenem ertapenem has limited activity against P. aeruginosa and is not associated with imipenem-resistant P. aeruginosa (IMP-R PA) in vitro. This retrospective, group-level, longitudinal study collected patient, antibiotic use, and resistance data from 2001 to 2005 using a hospital database containing information on 9 medical wards. A longitudinal data time series analysis was done to evaluate the association between carbapenem use (defined daily doses, or DDDs) and IMP-R PA. A total of 139 185 patient admissions were included, with 541 150 antibiotics DDDs prescribed: 4637 DDDs of group 2 carbapenems and 2130 DDDs of ertapenem. A total of 779 IMP-R PA were isolated (5.6 cases/1000 admissions). Univariate analysis found a higher incidence of IMP-R PA with group 2 carbapenems (P < 0.001), aminoglycosides (P = 0.034), and penicillins (P = 0.05), but not with ertapenem. Multivariate analysis showed a yearly increase in incidence of IMP-R-PA (3.8%, P < 0.001). Group 2 carbapenem use was highly associated with IMP-R PA, with a 20% increase in incidence (P = 0.0014) for each 100 DDDs. Group 2 carbapenem use tended to be associated with an increased proportion of IMP-R PA (P = 0.0625) in multivariate analysis. Ertapenem was not associated with IMP-R PA. These data would support preferentially prescribing ertapenem rather than group 2 carbapenems where clinically appropriate.
authors.affiliation: Division of Epidemiology, Tel-Aviv Sourasky Medical Center, Tel-Aviv 64239, Israel. yehudac@tasmc.health.gov.il
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Carmeli
authors.forename: Shiri Klarfeld
authors.initials: SK
authors.lastname: Lidji
authors.forename: Esther
authors.initials: E
authors.lastname: Shabtai
authors.forename: Shiri
authors.initials: S
authors.lastname: Navon-Venezia
authors.forename: Mitchell J
authors.initials: MJ
authors.lastname: Schwaber
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D015780:Carbapenems / Q000494:pharmacology* / Q000627:therapeutic use; D004363:Drug Utilization / Q000706:statistics & numerical data; D006801:Humans; D015378:Imipenem / Q000494:pharmacology* / Q000627:therapeutic use; D008137:Longitudinal Studies; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000302:isolation & purification; D012189:Retrospective Studies; D018440:beta-Lactam Resistance
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D015378:Imipenem