In vitro activity of various combinations of antimicrobials against carbapenem-resistant Acinetobacter species in Singapore

Outbreaks of carbapenem-resistant Acinetobacter species have emerged, especially in Singapore. Combination therapy may be the only viable option until new antibiotics are available. The objective of this study was to identify potential antimicrobial combinations against carbapenem-resistant Acinetobacter baumannii and Acinetobacter species in Singapore. From an ongoing surveillance program, two isolates of A. baumannii and an isolate of Acinetobacter species that were multidrug resistant were selected on the basis of their unique resistance mechanisms. The two A. baumannii isolates carried the carbapenemase bla(OXA-23)-like gene and the Acinetobacter species carried a metallo-beta-lactamase IMP-4 gene. Time-kill studies were conducted with approximately 10(5) CFU ml(-1) at baseline with 0.5 times minimum inhibitory concentrations (MICs) of polymyxin B and tigecycline, and at a maximally achievable clinical concentration of meropenem(64 microg ml(-1)) and rifampicin(2 microg ml(-1)), alone and in combinations. The MICs (microg ml(-1)) of Acinetobacter species A105, A. baumannii AB112 and A. baumannii AB8879 to polymyxin B/tigecycline/rifampicin/meropenem were found to be 1/0.5/4/64, 1/4/4/32 and 2/2/2/64, respectively. In time-kill studies, enhanced combined killing effects were observed in the tigecycline-rifampicin combination; the tigecycline-rifampicin and rifampicin-polymyxin B combination; and the rifampicin-polymyxin B combination for Acinetobacter species A105, A. baumannii AB112 and A. baumannii AB8879, respectively, with >5 log kill at 24 h suggesting synergism, with no regrowth observed at 72 h. These findings demonstrate that in vitro synergy of antibiotic combinations in carbapenem-resistant Acinetobacter species may be strain dependent. It may guide us in choosing a preemptive therapy for carbapenem-resistant Acinetobacter species infections and warrants further investigations.

Medienart:

E-Artikel

Erscheinungsjahr:

2009

Erschienen:

2009

Enthalten in:

Zur Gesamtaufnahme - volume:62

Enthalten in:

The Journal of antibiotics - 62(2009), 12 vom: 19. Dez., Seite 675-9

Sprache:

Englisch

Beteiligte Personen:

Lim, Tze-Peng [VerfasserIn]
Tan, Thean-Yen [VerfasserIn]
Lee, Winnie [VerfasserIn]
Sasikala, Suranthran [VerfasserIn]
Tan, Thuan-Tong [VerfasserIn]
Hsu, Li-Yang [VerfasserIn]
Kwa, Andrea L [VerfasserIn]

Links:

Volltext

Themen:

Anti-Bacterial Agents
Bacterial Proteins
Beta-Lactamases
Carbapenems
EC 3.5.2.6
Journal Article
Research Support, Non-U.S. Gov't

Anmerkungen:

Date Completed 07.01.2010

Date Revised 18.03.2022

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1038/ja.2009.99

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM19248253X