In Vitro Synergistic Effects of Antimicrobial Combinations on Extensively Drug-Resistant Pseudomonas aeruginosa and Acinetobacter baumannii Isolates.
10.3343/alm.2016.36.2.138
- Author:
Hyukmin LEE
1
;
Kyung Ho ROH
;
Seong Geun HONG
;
Hee Bong SHIN
;
Seok Hoon JEONG
;
Wonkeun SONG
;
Young UH
;
Dongeun YONG
;
Kyungwon LEE
Author Information
1. Department of Laboratory Medicine, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea.
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
In vitro synergy;
Combination chemotherapy;
Pseudomonas aeruginosa;
Acinetobacter baumannii
- MeSH:
Acinetobacter baumannii/*drug effects/genetics/isolation & purification;
Aminoglycosides/pharmacology;
Anti-Infective Agents/*pharmacology;
Bacterial Proteins/genetics/metabolism;
Drug Resistance, Multiple, Bacterial/*drug effects;
Drug Synergism;
Fluoroquinolones/pharmacology;
Imipenem/pharmacology;
Microbial Sensitivity Tests;
Polymerase Chain Reaction;
Pseudomonas aeruginosa/*drug effects/genetics/isolation & purification;
beta-Lactamases/genetics/metabolism
- From:Annals of Laboratory Medicine
2016;36(2):138-144
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: Extensively drug-resistant (XDR) Pseudomonas aeruginosa and Acinetobacter baumannii are a threat to hospitalized patients. We evaluated the effects of antimicrobial combinations on XDR P. aeruginosa and A. baumannii isolates. METHODS: P. aeruginosa and A. baumannii isolates, which were resistant to all antibiotics except colistin (CL), were collected from eight hospitals in Korea. Genes encoding metallo-beta-lactamases (MBLs) and OXA carbapenemases were detected by PCR in eight P. aeruginosa and 30 A. baumannii isolates. In vitro synergy of antimicrobial combinations was tested by using the checkerboard method. RESULTS: Minimum inhibitory concentrations of beta-lactams, aminoglycosides, and fluoroquinolones were very high, while that of CL was low for majority of XDR P. aeruginosa and A. baumannii isolates. Antimicrobial combinations including Imipenem (IPM)-CL, ceftazidime (CAZ)-CL, and rifampin (RIF)-CL exerted only additive/indifferent effects on majority of XDR P. aeruginosa isolates. Proportions of XDR A. baumannii isolates that showed synergistic and additive/indifferent inhibition after treatment with antimicrobial combinations used are as follows: IPM-ampicillin-sulbactam (AMS), 17% and 80% isolates, respectively; IPM-rifampin (RIF), 13% and 81% isolates, respectively; IPM-CL, 13% and 87% isolates, respectively; and RIF-COL, 20% and 73% isolates, respectively. Significant proportion (19%) of XDR P. aeruginosa isolates produced MBLs, and majority (82%) of A. baumannii isolates produced either MBLs or OXA-23. CONCLUSIONS: Our results suggest that combinations of IPM-AMS, IPM-RIF, IPM-CL, and RIF-CL are more useful than individual drugs for treating 13-20% of XDR A. baumannii infections.
