In-Vitro Evaluation of Different Antimicrobial Combinations with and without Colistin Against Carbapenem-Resistant Acinetobacter Baumannii

Carbapenem-resistant Acinetobacter baumannii (CR-Ab) infections are associated with high morbidity and mortality. The aim of the study was to evaluate the in-vitro activity of different antimicrobial combinations (with and without colistin, COL) against clinical isolates of CR-Ab collected from patients with CR-Ab infection, including unconventional combinations such as COL + VANcomycin (VAN) and COL + rifampin (RIF). CR-Ab strains were collected from hospitalized patients at Sapienza University of Rome. Antimicrobial susceptibility patterns were determined throughout MIC50/90s whereas the synergistic activity was evaluated by qualitative (i.e., checkerboard) and quantitative (i.e., killing studies) methods. All the strains were found oxacillinase (OXA) producers and tigecycline (TIG) sensitive whereas 2 strains were resistant to COL. Application of the checkerboard method indicated complete synergism in COL combinations at different extension: 21.4%, 57.1%, 42.8%, 35.7% for COL + meropenem (MEM), COL + RIF, COL + VAN and COL + TIG, respectively, with the non-conventional combinations COL + VAN and COL + RIF exhibiting the highest rate of synergism. Regarding COL-free combination, complete synergism was observed in 35.7% of the strains for MEM + TIG. Killing studies showed that the combinations COL + MEM, COL + TIG and MEM + TIG were bactericidal and synergistic against both colistin-sensitive and low colistin-resistant strains whereas only the combinations COL + VAN and COL + RIF showed an early and durable bactericidal activity against all the tested strains, with absence of growth at 24 h. This study demonstrated that COL-based combinations lead to a high level of synergic and bactericidal activity, especially COL + VAN and COL + RIF, even in the presence of high level of COL resistance.

Medienart:

E-Artikel

Erscheinungsjahr:

2019

Erschienen:

2019

Enthalten in:

Zur Gesamtaufnahme - volume:24

Enthalten in:

Molecules (Basel, Switzerland) - 24(2019), 5 vom: 03. März

Sprache:

Englisch

Beteiligte Personen:

Oliva, Alessandra [VerfasserIn]
Garzoli, Stefania [VerfasserIn]
De Angelis, Massimiliano [VerfasserIn]
Marzuillo, Carolina [VerfasserIn]
Vullo, Vincenzo [VerfasserIn]
Mastroianni, Claudio M [VerfasserIn]
Ragno, Rino [VerfasserIn]

Links:

Volltext

Themen:

6Q205EH1VU
Antimicrobial combinations
Carbapenem-resistant A. baumannii
Carbapenems
Colistin
Drug Combinations
Journal Article
Rifampin
Synergy
Time-kill studies
VJT6J7R4TR
Vancomycin
Z67X93HJG1

Anmerkungen:

Date Completed 13.06.2019

Date Revised 25.02.2020

published: Electronic

Citation Status MEDLINE

doi:

10.3390/molecules24050886

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM294566007