1
|
Conti P, Lazzaro LM, Longo F, Lenzo F, Giardina A, Fortuna SA, Stefani S, Campanile F. Unveiling the Relationship between Ceftobiprole and High-Molecular-Mass (HMM) Penicillin-Binding Proteins (PBPs) in Enterococcus faecalis. Antibiotics (Basel) 2024; 13:65. [PMID: 38247624 PMCID: PMC10812503 DOI: 10.3390/antibiotics13010065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Revised: 12/30/2023] [Accepted: 01/06/2024] [Indexed: 01/23/2024] Open
Abstract
Low-affinity PBP4, historically linked to penicillin resistance in Enterococcus faecalis, may still have affinity for novel cephalosporins. Ceftobiprole (BPR) is a common therapeutic choice, even with PBP4-related overexpression and amino acid substitution due to mutations. Our study aims to explore the interaction between BPR and High-Molecular-Mass (HMM) low-reactive PBPs in Penicillin-Resistant-Ampicillin-Susceptible/Ceftobiprole Non-Susceptible (PRAS/BPR-NS) E. faecalis clinical isolates. We conducted competition assays examining class A and B HMM PBPs from four PRAS/BPR-NS E. faecalis strains using purified membrane proteins and fluorescent penicillin (Bocillin FL), in treated and untreated conditions. Interaction strength was assessed calculating the 50% inhibitory concentration (IC50) values for ceftobiprole, by analyzing fluorescence intensity trends. Due to its low affinity, PBP4 did not display significant acylation among all strains. Moreover, both PBP1a and PBP1b showed a similar insensitivity trend. Conversely, other PBPs showed IC50 values ranging from 1/2-fold to 4-fold MICs. Upon higher BPR concentrations, increased percentages of PBP4 inhibition were observed in all strains. Our results support the hypothesis that PBP4 is necessary but not sufficient for BPR resistance, changing the paradigm for enterococcal cephalosporin resistance. We hypothesize that cooperation between class B PBP4 and at least one bifunctional class A PBP could be required to synthesize peptidoglycan and promote growth.
Collapse
Affiliation(s)
- Paola Conti
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), Section of Microbiology, University of Catania, 95123 Catania, Italy; (P.C.); (L.M.L.); (F.L.); (F.L.); (A.G.); (S.A.F.); (S.S.)
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
| | - Lorenzo Mattia Lazzaro
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), Section of Microbiology, University of Catania, 95123 Catania, Italy; (P.C.); (L.M.L.); (F.L.); (F.L.); (A.G.); (S.A.F.); (S.S.)
| | - Fabio Longo
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), Section of Microbiology, University of Catania, 95123 Catania, Italy; (P.C.); (L.M.L.); (F.L.); (F.L.); (A.G.); (S.A.F.); (S.S.)
- Department of Public Health and Pediatrics, University of Torino, 10126 Turin, Italy
| | - Federica Lenzo
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), Section of Microbiology, University of Catania, 95123 Catania, Italy; (P.C.); (L.M.L.); (F.L.); (F.L.); (A.G.); (S.A.F.); (S.S.)
| | - Alessandra Giardina
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), Section of Microbiology, University of Catania, 95123 Catania, Italy; (P.C.); (L.M.L.); (F.L.); (F.L.); (A.G.); (S.A.F.); (S.S.)
| | - Sebastiano Alberto Fortuna
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), Section of Microbiology, University of Catania, 95123 Catania, Italy; (P.C.); (L.M.L.); (F.L.); (F.L.); (A.G.); (S.A.F.); (S.S.)
| | - Stefania Stefani
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), Section of Microbiology, University of Catania, 95123 Catania, Italy; (P.C.); (L.M.L.); (F.L.); (F.L.); (A.G.); (S.A.F.); (S.S.)
| | - Floriana Campanile
- Department of Biomedical and Biotechnological Sciences (BIOMETEC), Section of Microbiology, University of Catania, 95123 Catania, Italy; (P.C.); (L.M.L.); (F.L.); (F.L.); (A.G.); (S.A.F.); (S.S.)
| |
Collapse
|
2
|
Penicillin-Binding Proteins and Alternative Dual-Beta-Lactam Combinations for Serious Enterococcus faecalis Infections with Elevated Penicillin MICs. Antimicrob Agents Chemother 2023; 67:e0087122. [PMID: 36719223 PMCID: PMC9933722 DOI: 10.1128/aac.00871-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Ampicillin-ceftriaxone has become a first-line therapy for Enterococcus faecalis endocarditis. We characterized the penicillin-binding protein (PBP) profiles of various E. faecalis strains and tested for synergy to better inform beta-lactam options for the treatment of E. faecalis infections. We assessed the affinity of PBP2B from elevated-MIC strain E. faecalis LS4828 compared to type strain JH2-2 using the fluorescent beta-lactam Bocillin FL. We also characterized pbp4 and pbpA structures and PBP4 and PBP2B expression and used deletion and complementation studies to assess the impact of PBP2B on the levels of resistance. We tested penicillin-susceptible and -resistant E. faecalis isolates against ceftriaxone or ceftaroline combinations with other beta-lactams in 24-h time-kill studies. Two penicillin-susceptible strains (JH2-2 and L2052) had identical pbp sequences and similar PBP expression levels. One reduced-penicillin-susceptibility strain (L2068) had pbp sequences identical to those of the susceptible strains but expressed more PBP4. The second decreased-penicillin-susceptibility strain (LS4828) had amino acid substitutions in both PBP4 and PBP2B and expressed increased quantities of both proteins. PBP2B did not appear to contribute significantly to the elevated beta-lactam MICs. No synergy was demonstrable against the strains with both mutated PBPs and increased expression (L2068 and LS4828). Meropenem plus ceftriaxone or ertapenem plus ceftriaxone demonstrated the most consistent synergistic activity. PBP2B of strain LS4828 does not contribute significantly to reduced penicillin susceptibility. Neither the MIC nor the level of PBP expression correlated directly with the identified synergistic combinations when tested at static subinhibitory concentrations.
Collapse
|
3
|
Meropenem plus Ceftaroline Is Active against Enterococcus faecalis in an In Vitro Pharmacodynamic Model Using Humanized Dosing Simulations. Antimicrob Agents Chemother 2022; 66:e0042622. [PMID: 36154173 DOI: 10.1128/aac.00426-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The standard of care for serious Enterococcus faecalis infections is ampicillin plus ceftriaxone. Ampicillin's inconvenient dosing schedule, drug instability, allergy potential, along with ceftriaxone's high risk for Clostridioides difficile infection and its promotion of vancomycin-resistant enterococci (VRE), led our team to explore alternative options. This work aimed to understand the role of carbapenems in combination with cephalosporins in these infections. We selected two ampicillin and penicillin susceptible E. faecalis strains (AMP-MIC 0.5-2 μg/mL; PCN-MIC 2 μg/mL) and simulated human therapeutic dosing regimens in a 48-h in vitro pharmacodynamic model (IVPD) with ampicillin (2g q4h), ertapenem (1g q24h), meropenem (2g q8h), ceftriaxone (2g q12h), and ceftaroline (600 mg q8h). As expected, ampicillin plus ceftriaxone demonstrated enhanced activity compared with ampicillin monotherapy with no MIC increases in either isolate. Meropenem and ceftaroline demonstrated significant kill against both isolates, with no regrowth or MIC increases occurring. Meropenem plus ceftriaxone also demonstrated significant kill, and while no MIC increases were identified for meropenem, there was minor regrowth and larger standard deviations. Ertapenem combined with either ceftriaxone or ceftaroline enhanced activity at 24 h, but at 48 h, regrowth occurred, and ertapenem MIC increases were noted. Meropenem-based combination therapy against E. faecalis may provide clinicians with another regimen to treat severe E. faecalis infections. Meropenem plus ceftaroline was as active as the standard of care treatment (ampicillin plus ceftriaxone) and may serve as an alternative for serious E. faecalis infections. Further studies are warranted to determine the clinical efficacy.
Collapse
|
4
|
Lazzaro LM, Cassisi M, Stefani S, Campanile F. Impact of PBP4 Alterations on β-Lactam Resistance and Ceftobiprole Non-Susceptibility Among Enterococcus faecalis Clinical Isolates. Front Cell Infect Microbiol 2022; 11:816657. [PMID: 35127564 PMCID: PMC8811369 DOI: 10.3389/fcimb.2021.816657] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 12/23/2021] [Indexed: 12/18/2022] Open
Abstract
Penicillin-resistance among Enterococcus faecalis clinical isolates has been recently associated with overexpression or aminoacidic substitutions in low-affinity PBP4. Ceftobiprole (BPR), a new-generation cephalosporin, is a therapeutic option against E. faecalis. Here, we present evidence that pbp4 gene sequence alterations may influence the expression level of the gene and ceftobiprole binding to PBP4 in E. faecalis clinical isolates showing remarkable MDR-phenotypes, and how this could interfere with BPR in vitro antibacterial and bactericidal activity. Seven E. faecalis strains from bloodstream infections were analyzed for their antibiotic and β-lactam resistance. BPR bactericidal activity was assessed by time-kill analysis; pbp4 genes were sequenced and pbp4 relative expression levels of transcription were performed by RT-qPCR. Five penicillin-resistant ampicillin-susceptible (PRAS) isolates were detected, 4 of which were also BPR non-susceptible (BPR-NS). In the time-kill experiments, BPR exposure resulted in a potent bactericidal activity (3-5 log10 reduction) at the different concentrations tested. pbp4 gene sequence analysis revealed some mutations that may account for the changes in PBP4 affinity and MIC increase in the 4 BPR-NS strains (MICs 4-16 mg/L): the deletion of an adenine (delA) in the promoter region in all PRAS/BPR-NS strains; 12 different amino acid substitutions, 7 of which were next to the PBP catalytic-sites. The most significant were: T418A, located 6 amino acids (aa) upstream of the catalytic-serine included in the 424STFK427motif I; L475Q, 7 aa upstream of the 482SDN484motif II; V606A and the novel Y605H, 13/14 aa upstream of the 619KTGT622motif III. Taken together, our data showed that elevated BPR MICs were attributable to increased transcription of pbp4 - associated with a single upstream adenine deletion and PBP4 alterations in the catalytic-site motifs – which might interfere with the formation of the BPR/PBP4 complex. pbp4 molecular alterations may account for the changes in PBP4 affinity and MIC increase, without affecting BPR cidal activity. Indeed, our in vitro dynamic analysis by time-kill assays showed that BPR exerted a bactericidal activity against E. faecalis clinical isolates, despite their MDR phenotypes.
Collapse
|
5
|
Beganovic M, Luther MK, Rice LB, Arias CA, Rybak MJ, LaPlante KL. A Review of Combination Antimicrobial Therapy for Enterococcus faecalis Bloodstream Infections and Infective Endocarditis. Clin Infect Dis 2019; 67:303-309. [PMID: 29390132 DOI: 10.1093/cid/ciy064] [Citation(s) in RCA: 126] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 01/26/2018] [Indexed: 12/20/2022] Open
Abstract
Enterococci, one of the most common causes of hospital-associated infections, are responsible for substantial morbidity and mortality. Enterococcus faecalis, the more common and virulent species, causes serious high-inoculum infections, namely infective endocarditis, that are associated with cardiac surgery and mortality rates that remained unchanged for the last 30 years. The best cures for these infections are observed with combination antibiotic therapy; however, optimal treatment has not been fully elucidated. It is the purpose of this review to highlight treatment options and their limitations, and provide direction for future investigative efforts to aid in the treatment of these severe infections. While ampicillin plus ceftriaxone has emerged as a preferred treatment option, mortality rates continue to be high, and from a safety standpoint, ceftriaxone, unlike other cephalosporins, promotes colonization with vancomycin resistant-enterococci due to high biliary concentrations. More research is needed to improve patient outcomes from this high-mortality disease.
Collapse
Affiliation(s)
- Maya Beganovic
- College of Pharmacy, University of Rhode Island, Kingston.,Infectious Diseases Research Program, Providence Veterans Affairs Medical Center, Providence, Rhode Island
| | - Megan K Luther
- College of Pharmacy, University of Rhode Island, Kingston.,Infectious Diseases Research Program, Providence Veterans Affairs Medical Center, Providence, Rhode Island.,Center of Innovation in Long-Term Services and Supports, Providence Veterans Affairs Medical Center, Providence, Rhode Island
| | - Louis B Rice
- Rhode Island Hospital, Providence, Rhode Island, Providence, Rhode Island.,Warren Alpert Medical School of Brown University, Division of Infectious Diseases, Providence, Rhode Island
| | - Cesar A Arias
- Center for Antimicrobial Resistance and Microbial Genomics, Division of Infectious Diseases, Department of Internal Medicine and Department of Microbiology and Molecular Genetics, University of Texas Health Science Center at Houston (UTHealth) McGovern Medical School, Bogota, Colombia.,Center for Infectious Diseases, UTHealth School of Public Health, Bogota, Colombia.,Molecular Genetics and Antimicrobial Resistance Unit, International Center for Microbial Genomics, Universidad El Bosque, Bogota, Colombia
| | - Michael J Rybak
- Anti-Infective Research Laboratory, Department of Pharmacy Practice, Eugene Applebaum College of Pharmacy and Health Sciences, Michigan.,Department of Medicine, Division of Infectious Diseases, School of Medicine, Wayne State University, Michigan.,Department of Pharmacy Services, Detroit Receiving Hospital, Michigan
| | - Kerry L LaPlante
- College of Pharmacy, University of Rhode Island, Kingston.,Infectious Diseases Research Program, Providence Veterans Affairs Medical Center, Providence, Rhode Island.,Center of Innovation in Long-Term Services and Supports, Providence Veterans Affairs Medical Center, Providence, Rhode Island.,Warren Alpert Medical School of Brown University, Division of Infectious Diseases, Providence, Rhode Island
| |
Collapse
|
6
|
In vitro bactericidal activity of amoxicillin combined with different cephalosporins against endocarditis-associated Enterococcus faecalis clinical isolates. J Antimicrob Chemother 2019; 74:3511-3514. [DOI: 10.1093/jac/dkz388] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/27/2019] [Accepted: 08/09/2019] [Indexed: 12/22/2022] Open
Abstract
AbstractBackgroundThe combination of amoxicillin with cefazolin could be an interesting regimen for the empirical therapy of severe infective endocarditis, but its activity against enterococci is unknown.ObjectivesTo evaluate in vitro the bactericidal activity of the combination of amoxicillin with different cephalosporins including cefazolin.MethodsCombinations of amoxicillin (at MIC×¼) with cefazolin, cefotaxime, ceftriaxone, cefepime, ceftaroline or ceftobiprole (at the mean free plasma concentration) were studied using time–kill experiments for 10 endocarditis-associated Enterococcus faecalis strains and 2 reference strains.ResultsThe combinations amoxicillin/cefazolin, amoxicillin/cefotaxime, amoxicillin/ceftriaxone and amoxicillin/cefepime were synergistic at 12 and 24 h against 12/12 strains and amoxicillin/ceftobiprole and amoxicillin/ceftaroline against 10/12 strains. The combination amoxicillin/cefepime was bactericidal at 24 h against 9/12 strains, the combination amoxicillin/cefazolin against 8/12 strains, the combinations amoxicillin/ceftaroline, amoxicillin/cefotaxime and amoxicillin/ceftobiprole against 7/12 strains and the combination amoxicillin/ceftriaxone against 6/12 strains.ConclusionsThe combination amoxicillin/cefazolin is as synergistic and bactericidal in vitro as amoxicillin/cefotaxime or amoxicillin/ceftriaxone against E. faecalis.
Collapse
|
7
|
D'Arezzo S, Mazzarelli A, Venditti C, Nisii C, Petrosillo N, De Giuli C, Vulcano A, Paglia MG, Bordi E, Di Caro A, Taglietti F. Ceftaroline Plus Ampicillin Against Gram-Positive Organisms: Results from E-Test Synergy Assays. Microb Drug Resist 2017; 23:507-515. [PMID: 27526275 DOI: 10.1089/mdr.2016.0030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In an era of increasing drug resistance and limited numbers of antimicrobials in the drug production pipeline, healthcare-associated infections represent a growing public health threat. When therapeutic options are limited, clinicians often resort to using antimicrobial combinations that produce a synergistic effect on the target pathogen. Novel antibiotics are therefore welcome in the daily practice of medicine. For example, ceftaroline is a broad-spectrum cephalosporin active against a variety of bacteria, including methicillin-resistant Staphylococcus aureus, but with limited activity against enterococci, particularly Enterococcus faecium. In this study, we tested the efficacy of ceftaroline against clinical isolates of gram-positive bacteria (S. aureus, Enterococcus faecalis, and E. faecium) by the broth microdilution and E-test assays, and then evaluated the synergistic effect of ceftaroline and ampicillin using the E-test method. The time-kill assay was used to confirm the data on selected strains. This drug combination has been recently shown to be effective against E. faecalis and could offer the advantage of cost-effectiveness (compared to other synergistic associations) as well as good tolerability. The E-test was chosen because of its relative simplicity of use that makes it suitable for routine clinical laboratories as a quick tool to guide clinicians when confronted with difficult-to-treat infections that may require an empirical approach. Our results indicate the presence of a synergistic effect of ceftaroline and ampicillin on most of the strains used, especially E. faecium and E. faecalis. The fact that two of those Enterococcus strains were vancomycin resistant suggests that the possible use of this combination for combating the spread of vancomycin-resistant enterococci should be explored.
Collapse
Affiliation(s)
- Silvia D'Arezzo
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Antonio Mazzarelli
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Carolina Venditti
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Carla Nisii
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Nicola Petrosillo
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Chiara De Giuli
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Antonella Vulcano
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Maria Grazia Paglia
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Eugenio Bordi
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Antonino Di Caro
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| | - Fabrizio Taglietti
- "Lazzaro Spallanzani" National Institute for Infectious Diseases IRCCS , Rome, Italy
| |
Collapse
|
8
|
Werth BJ, Shireman LM. Pharmacodynamics of Ceftaroline plus Ampicillin against Enterococcus faecalis in an In Vitro Pharmacokinetic/Pharmacodynamic Model of Simulated Endocardial Vegetations. Antimicrob Agents Chemother 2017; 61:e02235-16. [PMID: 28096164 PMCID: PMC5365715 DOI: 10.1128/aac.02235-16] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 01/12/2017] [Indexed: 11/20/2022] Open
Abstract
The combination of ampicillin plus ceftaroline has been suggested to be more reliably synergistic against Enterococcus faecalis than ampicillin plus ceftriaxone using time-kill methods. The purpose of this study was to determine if this trend persists in a two-compartment model of simulated endocardial vegetations (SEV) using clinically relevant pharmacokinetic exposures of these antimicrobials. Three clinically derived E. faecalis strains were included in the study. The MICs of study antimicrobials were determined by broth microdilution. Simulations of ampicillin (2 g every 4 h [q4h]; maximum concentration of drug in serum [Cmax], 72.4 mg/liter; half-life [t1/2], 1.9 h), ceftaroline-fosamil (600 mg q8h; Cmax, 21.3 mg/liter; t1/2, 2.66 h), ceftriaxone (Cmax, 257 mg/liter; t1/2, 8 h), and ampicillin plus ceftaroline and ampicillin plus ceftriaxone were evaluated against 3 strains of E. faecalis isolated from patients with endocarditis in an in vitro PK/PD SEV model over 72 h, with a starting inoculum of ∼9 log10 CFU/g. All strains were susceptible to ampicillin (MIC, ≤2 mg/liter). Ceftaroline MICs varied from 2 to 16 mg/liter. All strains had ceftriaxone MICs of 256 mg/liter. W04 and W151 exhibited high-level aminoglycoside resistance but W07 did not. Ampicillin plus ceftaroline resulted in significantly greater reductions in CFU per gram by 72 h than ampicillin for all strains (P ≤ 0.025) than ampicillin plus ceftriaxone for W04 (P = 0.019) but not W07 or W151 (P ≥ 0.15). A 4-fold increase in ampicillin MIC was observed for W07 at 72 h, but this was prevented by the addition of ceftaroline or ceftriaxone. The combination of ampicillin plus ceftaroline appears to be at least as efficacious as ampicillin plus ceftriaxone and may lead to improved activity against some strains of E. faecalis, but these differences may be small and the clinical significance should not be overestimated.
Collapse
Affiliation(s)
- Brian J Werth
- Department of Pharmacy University of Washington School of Pharmacy, Seattle, Washington, USA
| | - Laura M Shireman
- Department of Pharmacy University of Washington School of Pharmacy, Seattle, Washington, USA
| |
Collapse
|
9
|
Luther MK, Rice LB, LaPlante KL. Ampicillin in Combination with Ceftaroline, Cefepime, or Ceftriaxone Demonstrates Equivalent Activities in a High-Inoculum Enterococcus faecalis Infection Model. Antimicrob Agents Chemother 2016; 60:3178-82. [PMID: 26926624 PMCID: PMC4862448 DOI: 10.1128/aac.03126-15] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 02/20/2016] [Indexed: 11/20/2022] Open
Abstract
Ampicillin-ceftriaxone combination therapy has become a predominant treatment for serious Enterococcus faecalis infections, such as endocarditis. Unfortunately, ceftriaxone use is associated with future vancomycin-resistant enterococcus colonization. We evaluated E. faecalis in an in vitro pharmacodynamic model against simulated human concentration-time profiles of ampicillin plus ceftaroline, cefepime, ceftriaxone, or gentamicin. Ampicillin-cefepime and ampicillin-ceftaroline demonstrated activities similar to those of ampicillin-ceftriaxone against E. faecalis.
Collapse
Affiliation(s)
- Megan K Luther
- Department of Pharmacy Practice, University of Rhode Island, Kingston, Rhode Island, USA Rhode Island Infectious Diseases (RIID) Research Program, Veterans Affairs Medical Center, Providence, Rhode Island, USA
| | - Louis B Rice
- Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA Rhode Island Hospital, Providence, Rhode Island, USA
| | - Kerry L LaPlante
- Department of Pharmacy Practice, University of Rhode Island, Kingston, Rhode Island, USA Rhode Island Infectious Diseases (RIID) Research Program, Veterans Affairs Medical Center, Providence, Rhode Island, USA Warren Alpert Medical School, Brown University, Providence, Rhode Island, USA
| |
Collapse
|