Flucloxacillin and cefazolin for treatment of Staphylococcus aureus bloodstream infection.

PURPOSE: Antistaphylococcal penicillins and cefazolin have been used as first line therapy in Methicillin-susceptible Staphylococcus aureus bloodstream infection. While efficacy of both regimens seems to be similar, the compounds may differ with regard to tolerability. This study aims to describe the clinical use of cefazolin and flucloxacillin, focussing on discontinuation or change of anti-infective agent due to adverse events. METHODS: This observational prospective study was conducted at two German tertiary care centres with an internal recommendation of flucloxacillin for MSSA-BSI in one, and of cefazolin in the other centre. Adverse events were registered weekly under treatment and at a 90-day follow-up. Descriptive analysis was complemented by a propensity score analysis comparing adverse events (stratified rank-based test applied to the sum of Common Terminology Criteria for adverse events ratings per patient). RESULTS: Of 71 patients included, therapy was initiated with flucloxacillin in 56 (79%), and with cefazolin in 15 (21%). The propensity score analysis indicates a statistically significant difference concerning the severity of adverse events between the treatment groups in favour of cefazolin (p = 0.019). Adverse events led to discontinuation of flucloxacillin in 7 individuals (13% of all patients receiving flucloxacillin). Clinical outcome was not different among treatment groups. CONCLUSION: Using cefazolin rather than flucloxacillin as a first line agent for treatment of MSSA-BSI is supported by these clinical data.

Antistaphylococcal penicillins vs. cefazolin in the treatment of methicillin-susceptible Staphylococcus aureus infective endocarditis: a quasi-experimental monocentre study.

Whether cefazolin is as effective and safer than antistaphylococcal penicillins (ASPs) for the treatment of methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis (IE) is still debated in the absence of a randomized controlled trial. In this quasi-experimental study, we aimed to assess the effectiveness and safety of these two treatments in MSSA-IE, using the ASPs nationwide shortage in April 2016 as a unique opportunity to overcome the indication bias associated with observational studies. In this single-centre study, we compared patients with Duke-Li definite MSSA-IE treated with ASPs from January 2015 to March 2016 versus those treated with cefazolin from April 2016 to December 2018, when ASPs were not available. Effectiveness outcome was 90-day all-cause mortality. Safety outcomes included significant decrease in GFR and significant increase in serum liver enzymes. Logrank test was used to compare survival rates. Of 73 patients with MSSA-IE, 35 and 38 were treated with ASPs and cefazolin, respectively. Baseline patients' characteristics (demography, native or prosthetic valve IE, clinical characteristics, cardiac and septic complications) were similar between groups. Ninety-day all-cause mortality was 28.6% and 21.1%, in patients treated with ASPs and cefazolin, respectively (logrank p = 0.5727). There was no difference between groups for incident renal or liver toxicity events: acute kidney injury 45.7% vs. 44.7% (p = 0.933), increased ALT 5.7% vs. 13.2% (p = 0.432), bilirubin increase 5.7% vs. 10.5% (p = 0.676), in ASPs vs. cefazolin groups, respectively. In this quasi-experimental, effectiveness and safety did not statistically differ between ASPs and cefazolin for MSSA-IE treatment.

Retrospective Analysis of Adverse Drug Events Between Nafcillin Versus Cefazolin for Treatment of Methicillin-Susceptible Staphylococcus aureus Infections.

Background: Nafcillin or cefazolin are drugs of choice for methicillin-susceptible Staphylococcus aureus (MSSA) infections. Prior studies indicate a higher incidence of acute kidney injury (AKI) with nafcillin, although AKI classification and time to occurrence is not well described. Objective: To characterize the incidence and time to adverse drug events for nafcillin versus cefazolin in the inpatient setting. Methods: A retrospective cohort study evaluated hospitalized, adult patients receiving intravenous nafcillin or cefazolin for treatment of MSSA infection. Incidence and time to AKI based on RIFLE criteria were measured. Secondary end points included antibiotic discontinuation and incidence of neutropenia, thrombocytopenia, elevated transaminases, and Clostridioides difficile infection (CDI). Results: Of 324 patients who received nafcillin (n = 119) or cefazolin (n = 205), higher rates of AKI were found for nafcillin versus cefazolin (19% vs 2%, respectively; P < 0.0001). Median time to AKI with nafcillin was 6.5 days (range, 3-14 days). The majority of patients were classified as RIFLE "Risk" stratum. Nafcillin treatment discontinuations were more frequent than for cefazolin (17.6% vs 0.9%, respectively; P < 0.0001). Nafcillin was an independent predictor of AKI (odds ratio = 12.4; 95% CI = 4.14-47.60, P < 0.0001). No differences in neutropenia, thrombocytopenia, elevated transaminases, or CDI were observed. Conclusion and Relevance: Nafcillin displayed higher rates of AKI at a median of 1 week of therapy, which provides a framework for clinician monitoring and consideration of antibiotic modification. Most patients developed "Risk" class AKI (RIFLE classification), which may be reversible with prompt intervention.

Systematic Review and Meta-analysis of the Safety of Antistaphylococcal Penicillins Compared to Cefazolin.

Recent studies and experience suggest that cefazolin might be equally as effective as antistaphylococcal penicillins for methicillin-susceptible Staphylococcus aureus (MSSA), with a better safety profile and lower cost. The objective of these meta-analyses was to compare the safeties of antistaphylococcal penicillins and cefazolin. The PubMed, Embase, and International Pharmaceutical Abstracts databases and websites for clinical trial registries through 23 June 2017 were searched. In addition, recent abstracts from infectious disease and pharmacy conferences were reviewed. We estimated Peto odds ratios (ORs) with 95% confidence intervals (CIs) using random-effects models. One analysis focused on hospitalized patients, and the other focused on outpatients. Eleven retrospective studies of hospitalized patients and three retrospective studies of outpatients were included. In hospitalized patients, lower rates of nephrotoxicity (Peto OR, 0.225; 95% CI, 0.127 to 0.513), acute interstitial nephritis (Peto OR, 0.189; 95% CI, 0.053 to 0.675), hepatotoxicity (Peto OR, 0.160; 95% CI, 0.066 to 0.387), and drug discontinuation due to adverse reactions (Peto OR, 0.192; 95% CI, 0.089 to 0.414) were found with cefazolin. In outpatients, lower rates of nephrotoxicity (Peto OR, 0.372; 95% CI, 0.192 to 0.722), hepatotoxicity (Peto OR, 0.313; 95% CI, 0.156 to 0.627), and hypersensitivity reactions (Peto OR, 0.372; 95% CI, 0.201 to 0.687) were observed with cefazolin. Compared to antistaphylococcal penicillins, cefazolin was associated with significant reductions in nephrotoxicity and hepatotoxicity in hospitalized patients and outpatients. Additionally, cefazolin was associated with lower likelihoods of discontinuation due to side effects in hospitalized patients and hypersensitivity reactions in outpatients. Cefazolin should be considered a first-line option for patients with MSSA infections for which efficacy is presumed to be similar to that of antistaphylococcal penicillin therapy.

Efficacy and safety of cefazolin versus antistaphylococcal penicillins for the treatment of methicillin-susceptible Staphylococcus aureus bacteremia: a systematic review and meta-analysis.

BACKGROUND: Antistaphylococcal penicillins (ASPs) and cefazolin have become the most frequent choices for the treatment of methicillin-susceptible Staphylococcus aureus (MSSA) infections. However, the best therapeutic agent to treat MSSA bacteremia remains to be established. METHODS: We conducted a systematic review and meta-analysis to evaluate the efficacy and safety of these two regimens for the treatment of MSSA bacteremia. PubMed, EMBASE and the Cochrane Library from inception to February 2018 were searched. The primary outcome was mortality. The secondary outcomes included treatment failure, recurrence of bacteremia, adverse effects (AEs) and discontinuation due to AEs. Data were extracted and pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. RESULTS: A total of ten observational studies met the inclusion criteria. The results indicate that compared to ASPs, cefazolin was associated with significant reduction in mortality (OR, 0.69; 95% CI, 0.58 to 0.82; I2 = 3.4%) and clinical failure (OR, 0.56; 95% CI, 0.37 to 0.85; I2 = 44.9%) without increasing the recurrence of bacteremia (OR, 1.12; 95% CI, 0.94 to 1.34; I2 = 0%). There were no significant differences for the risk of anaphylaxis (OR, 0.91; 95% CI, 0.36 to 2.99; I2 = 0%) or hematotoxicity (OR, 0.56; 95% CI, 0.17 to 1.88; I2 = 0%). However, nephrotoxicity (OR, 0.36; 95% CI, 0.16 to 0.81; I2 = 0%) and hepatotoxicity (OR, 0.12; 95% CI, 0.04 to 0.41; I2 = 0%) were significantly lower in the cefazolin group. Moreover, cefazolin was associated with lower probability of discontinuation due to AEs compared with the ASPs (OR, 0.24; 95% CI, 0.12 to 0.48; I2 = 18%). CONCLUSION: The results of present study favor the application of cefazolin and should be regarded as important evidence to help make clinical decisions in choosing a treatment option for treating MSSA bacteremia.

Cefazolin in the treatment of central nervous system infections: A narrative review and recommendation.

Infections of the central nervous system (CNS) are complex to treat and associated with significant morbidity and mortality. Historically, antistaphylococcal penicillins such as nafcillin were recommended for the treatment of methicillin-susceptible staphylococcal CNS infections. However, the use of antistaphylococcal penicillins presents challenges, such as frequent dosing administration and adverse events with protracted use. This narrative reviews available clinical and pharmacokinetic/pharmacodynamic (PK/PD) data for cefazolin in CNS infections and produces a recommendation for use. Based on the limited available evidence analyzed, dose optimized cefazolin is likely a safe and effective alternative to antistaphylococcal penicillins for a variety of CNS infections due to methicillin-susceptible Staphylococcus aureus. Given the site of infection and wide therapeutic index of cefazolin, practitioners may consider dosing cefazolin regimens of 2 g IV every 6 h or a continuous infusion of 8-10 g daily instead of 2 g IV every 8 h to optimize PK/PD properties.

The Cost-effectiveness of Cefazolin Compared With Antistaphylococcal Penicillins for the Treatment of Methicillin-Sensitive Staphylococcus aureus Bacteremia.

BACKGROUND: Methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia is associated with significant morbidity, mortality, and hospitalization costs. Cefazolin and antistaphylococcal penicillins (ASPs), such as nafcillin, are the preferred treatments for MSSA bacteremia. The aim of this study was to compare the cost-effectiveness of each approach. METHODS: We constructed a decision-analytic model comparing the use of cefazolin with ASPs for the treatment of MSSA bacteremia. Cost-effectiveness was determined by calculating deaths averted and incremental cost-effectiveness ratios (ICERs). Uncertainty was addressed by plotting cost-effectiveness planes and acceptability curves for various willingness-to-pay thresholds. RESULTS: In the base-case analysis, the cost associated with the cefazolin strategy was $38 863.1, and the associated probability of survival was 0.91. For the ASP strategy, the cost was $48 578.8, and the probability of survival was 0.81. The incremental difference in cost between the 2 strategies was $9715.7, with hospital length of stay being the main driver of cost, and the incremental difference in effectiveness was 0.10. Overall, cefazolin results in savings of $97 156.8 per death averted (ICER, $-97 156.8/death averted). In the probabilistic analysis, at a willingness-to-pay of $50 000, cefazolin had a 68% chance of being cost-effective compared with ASPs. In cost-effectiveness acceptability curves, the cefazolin strategy was cost-effective in 73.5%-81.8% of simulations compared with ASP for a willingness-to-pay ranging up to $50 000. CONCLUSIONS: The use of cefazolin is a cost-effective strategy for the treatment of MSSA bacteremia and, when clinically appropriate, this strategy results in considerable health care cost-savings.

A large retrospective cohort study of cefazolin compared with flucloxacillin for methicillin-susceptible Staphylococcus aureus bacteraemia.

BACKGROUND AND OBJECTIVES: Antistaphylococcal penicillins (ASPs) are recommended as first-line treatment for invasive infections caused by methicillin-susceptible Staphylococcus aureus (MSSA). Cefazolin is an alternative option, but there is theoretical concern about its use as some MSSA strains produce beta-lactamases active against cefazolin. The study compared the outcomes in patients with MSSA infections treated with flucloxacillin and cefazolin. METHODS: We analysed data from The Australia and New Zealand Co-operative Outcomes of Staphylococcal Sepsis (ANZCOSS) observational study, which included all consecutive unique episodes of Staphylococcus aureus bacteraemia from 27 hospital-based or independent microbiology laboratories from January 2007 to September 2013. In this retrospective analysis of prospectively collected data, we compared 30-day all-cause mortality in patients with MSSA bacteraemia treated with flucloxacillin to that in patients treated with cefazolin. RESULTS: We included data from 7312 episodes of MSSA bacteremia and found no difference in 30-day mortality in those treated with flucloxacillin (731/6520 [11.2%, 95% CI 10.9-12.5%]) compared to cefazolin (83/792 [10.7%, 95% CI 8.4-12.8%]), OR 0.93 (95% CI 0.72-1.17). In a propensity-adjusted analysis, mortality remained non-significantly lower in the cefazolin group (aOR 0.86 [95% CI 0.65-1.14]). CONCLUSIONS: This study supports the results from previous observational studies from other regions, while extending them to Australasia and to a much larger number of patients. Although this observational study indicates cefazolin is likely to have equivalent or superior outcomes to ASPs for MSSA bacteraemia, this can only be convincingly proven by a properly designed randomised controlled trial.

ß-Lactam Therapy for Methicillin-Susceptible Staphylococcus aureus Bacteremia: A Comparative Review of Cefazolin versus Antistaphylococcal Penicillins.

Methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia is associated with high morbidity and mortality. Traditionally, antistaphylococcal penicillins (ASPs) have been considered the agents of choice for the treatment of MSSA bacteremia. Vancomycin has been demonstrated to have poorer outcomes in several studies and is only recommended for patients with severe penicillin allergies. Although cefazolin is considered as an alternative to the ASPs for patients with nonsevere penicillin allergies, cefazolin offers several pharmacologic advantages over ASPs, such as more convenient dosing regimens, and antimicrobial stewardship programs are increasingly using cefazolin as the preferential agent for MSSA infections as part of cost-saving initiatives. Concerns about susceptibility to hydrolysis by type A ß-lactamases, particularly at high inocula seen in deep-seated infections such as endocarditis; selective pressures from unnecessary gram-negative coverage; and lack of comparative clinical data have precluded recommending cefazolin as a first-line therapy for MSSA bacteremia. Recent clinical studies, however, have suggested similar clinical efficacy but better tolerability, with lower rates of discontinuation due to adverse drug reactions, of cefazolin compared with ASPs. Other variables, such as adequate source control (e.g., intravascular catheter removal, debridement, or drainage) and enhanced pharmacodynamics through aggressive cefazolin dosing, may mitigate the role of cefazolin inoculum effect and factor into determining improved clinical outcomes. In this review, we highlight the utility of cefazolin versus ASPs in the treatment of MSSA bacteremia with a focus on clinical efficacy and safety.