Bactericidal activity of penicillin, ceftriaxone, gentamicin and daptomycin alone and in combination against Aerococcus urinae

Hirzel, Cédric; Hirzberger, Lea; Furrer, Hansjakob; Endimiani, Andrea (2016). Bactericidal activity of penicillin, ceftriaxone, gentamicin and daptomycin alone and in combination against Aerococcus urinae. International journal of antimicrobial agents, 48(3), pp. 271-276. Elsevier 10.1016/j.ijantimicag.2016.05.007

[img] Text
1-s2.0-S0924857916301455-main.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (1MB) | Request a copy

Aerococcus urinae can cause severe infections (bacteraemia and endocarditis) that are associated with high mortality. However, data on the bactericidal and synergistic activity for clinically implemented antibiotics are scarce. Time-kill analyses were performed on two clinical isolates (AU1 and AU2) and the reference strain ATCC 700306 for penicillin (PG), ceftriaxone (CRO), gentamicin (GEN), daptomycin (DAP) and their combinations. AU1 and AU2 were CRO-resistant (MICs, 2 µg/mL) and ATCC 700306 was high-level GEN-resistant (MIC, 512 µg/mL), whereas all strains were PG- and DAP-susceptible (MICs, ≤0.125 and ≤1 µg/mL, respectively). CFU counts were determined at various time points from 0 to 48 h. All experiments were performed at 0.5×, 1×, 2× and 4× MIC. PG and CRO were not bactericidal for all strains, whereas DAP exhibited bactericidal activity at all concentrations for AU2 and ATCC 700306. The combination of PG or CRO with GEN was bactericidal for AU1 and AU2 at antibiotic concentrations ≥1× MIC. Bactericidal synergism was detected for PG or CRO combined with GEN in the two clinical isolates. PG plus CRO showed non-bactericidal synergism for ATCC 700306. DAP with GEN was synergistic at 1× MIC for AU1, whereas the killing activity of DAP was too pronounced to detect potential synergism in AU2. The combination of PG or CRO with GEN is synergistic and bactericidal. Moreover, these in vitro data suggest that DAP may represent a potential bactericidal treatment alternative against A. urinae. This finding could be important for the treatment of patients with a β-lactam allergy or renal insufficiency.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Service Sector > Institute for Infectious Diseases
04 Faculty of Medicine > Department of Haematology, Oncology, Infectious Diseases, Laboratory Medicine and Hospital Pharmacy (DOLS) > Clinic of Infectiology

UniBE Contributor:

Hirzel, Cédric, Hirzberger, Lea, Furrer, Hansjakob, Endimiani, Andrea


500 Science > 570 Life sciences; biology
600 Technology > 610 Medicine & health








Annelies Luginbühl

Date Deposited:

05 Sep 2016 14:30

Last Modified:

05 Dec 2022 14:57

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

Aerococcus urinae; Bactericidal; Synergism; Time–kill




Actions (login required)

Edit item Edit item
Provide Feedback