title: Acquisition of extensive drug-resistant Pseudomonas aeruginosa among hospitalized patients: risk factors and resistance mechanisms to carbapenems.
abstract: Extensive drug-resistant Pseudomonas aeruginosa (XDRPA) strains, defined as resistant to all available antipseudomonal antibiotics, have been reported recently. This study aimed to investigate the risk factors for XDRPA acquisition by patients and the resistance mechanisms to carbapenems. From June to November 2007, XDRPA isolates were collected from patients in eight tertiary care hospitals. A case-control study was performed to determine factors associated with XDRPA acquisition. EDTA-imipenem disc synergy tests, and polymerase chain reaction amplification and sequencing were performed to detect the presence of metallo-β-lactamases (MBLs). Risk factor analysis was performed for 33 patients. Mechanical ventilation [odds ratio (OR) 8.2, 95% confidence interval (CI) 1.3-52.2; P = 0.026] and APACHE II score (OR 1.2, 95% CI 1.0-1.3; P = 0.007) were identified as independent risk factors for XDRPA acquisition. Pulsed-field gel electrophoresis of XDRPA identified clonal epidemic isolates co-existing with sporadic isolates. Eight of 43 (19%) XDRPA isolates were shown to produce MBLs; four produced VIM-2 and four produced IMP-6. This study suggests a major role for mechanical ventilation in XDRPA acquisition. Moreover, pulsed-field gel electrophoresis identified a clonal epidemic within hospitals. Taken together, these results suggest that patient-to-patient transmission contributes to XDRPA acquisition in Korea.
authors.affiliation: Department of Internal Medicine, Gachon University Gil Hospital, Incheon, Republic of Korea.
authors.forename: Y S
authors.initials: YS
authors.lastname: Park
authors.forename: H
authors.initials: H
authors.lastname: Lee
authors.forename: B S
authors.initials: BS
authors.lastname: Chin
authors.forename: S H
authors.initials: SH
authors.lastname: Han
authors.forename: S G
authors.initials: SG
authors.lastname: Hong
authors.forename: S K
authors.initials: SK
authors.lastname: Hong
authors.forename: H Y
authors.initials: HY
authors.lastname: Kim
authors.forename: Y
authors.initials: Y
authors.lastname: Uh
authors.forename: H B
authors.initials: HB
authors.lastname: Shin
authors.forename: E J
authors.initials: EJ
authors.lastname: Choo
authors.forename: S-H
authors.initials: SH
authors.lastname: Han
authors.forename: W
authors.initials: W
authors.lastname: Song
authors.forename: S H
authors.initials: SH
authors.lastname: Jeong
authors.forename: K
authors.initials: K
authors.lastname: Lee
authors.forename: J M
authors.initials: JM
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015780:Carbapenems / Q000494:pharmacology*; D016022:Case-Control Studies; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006761:Hospitals; D006801:Humans; D008297:Male; D008875:Middle Aged; D011552:Pseudomonas Infections / Q000453:epidemiology* / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000302:isolation & purification; D056910:Republic of Korea / Q000453:epidemiology; D012121:Respiration, Artificial / Q000009:adverse effects; D012307:Risk Factors; D012720:Severity of Illness Index; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D000900:Anti-Bacterial Agents; D015780:Carbapenems; D001618:beta-Lactamases