Comparative outcomes of cefazolin versus antistaphylococcal penicillins in methicillin-susceptible Staphylococcus aureus infective endocarditis: a post hoc analysis of a prospective multicentre French cohort study

Effectiveness and safety of cefazolin versus cloxacillin in endocarditis due to methicillin-susceptible Staphylococcus spp.: a multicenter propensity weighted cohort study

PURPOSE

To compare the effectiveness and safety of cefazolin versus cloxacillin for the treatment of infective endocarditis (IE) due to methicillin-sensitive Staphylococci (MSS).

METHODS

Data were retrospectively collected on patients treated for a definite MSS endocarditis who received cefazolin or cloxacillin for at least 10 consecutive days in six French hospitals between January-1 2014 and December-31 2020. The primary endpoint was treatment failure defined as a composite of death within 90 days of starting antibiotherapy, or embolic event during antibiotherapy, or relapse of IE within 90 days of stopping antibiotherapy. We used Cox regression adjusted for the inverse probability of treatment weighting of receiving cefazolin.

RESULTS

192 patients were included (median age 67.8 years). IE was caused by S.aureus in 175 (91.1%) and by coagulase-negative staphylococci in 17 (8.9%). Ninety-four patients (48.9%) received cefazolin, and 98 (51%) received cloxacillin. 34 patients (34.7%) with cefazolin and 26 (27.7%) with cloxacillin met the composite primary endpoint, with no significant differences between groups (adjusted HR = 1.13, 95% CI 0.63 to 2.03). There were no significant differences in secondary efficacy endpoints or biological safety events.

CONCLUSION

The effectiveness of cefazolin did not significantly differ from cloxacillin for the treatment of MSS endocarditis.

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.

Update on the epidemiology, diagnosis, and management of infective endocarditis: A review

Despite advancements in the diagnosis and treatment of infective endocarditis (IE), the burden of IE has remained relatively high over the past decade. With an ageing population and an increasing proportion of healthcare-associated IE, the epidemiology of IE has undergone significant changes. Staphylococcus aureus has evolved as the most common causative microorganism, even in most low- and middle-income countries. Several imaging modalities and novel microbiological tests have emerged to facilitate the diagnosis of IE. Outpatient parenteral antibiotic treatment and oral step-down antibiotic treatment have become new trends for the management of IE. Early surgical intervention, particularly within seven days, should be considered in cases of IE with appropriate surgical indications. We comprehensively review the updated epidemiology, microbiology, diagnosis, and management of IE.

Contemporary use of cefazolin for MSSA infective endocarditis: analysis of a national prospective cohort

OBJECTIVES

This study aimed to assess the real use of cefazolin for methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis (IE) in the Spanish National Endocarditis Database (GAMES) and to compare it with antistaphylococcal penicillin (ASP).

METHODS

Prospective cohort study with retrospective analysis of a cohort of MSSA IE treated with cloxacillin and/or cefazolin. Outcomes assessed were relapse; intra-hospital, overall, and endocarditis-related mortality; and adverse events. Risk of renal toxicity with each treatment was evaluated separately.

RESULTS

We included 631 IE episodes caused by MSSA treated with cloxacillin and/or cefazolin. Antibiotic treatment was cloxacillin, cefazolin, or both in 537 (85%), 57 (9%), and 37 (6%) episodes, respectively. Patients treated with cefazolin had significantly higher rates of comorbidities (median Charlson Index 7, P <0.01) and previous renal failure (57.9%, P <0.01). Patients treated with cloxacillin presented higher rates of septic shock (25%, P = 0.033) and new-onset or worsening renal failure (47.3%, P = 0.024) with significantly higher rates of in-hospital mortality (38.5%, P = 0.017). One-year IE-related mortality and rate of relapses were similar between treatment groups. None of the treatments were identified as risk or protective factors.

CONCLUSION

Our results suggest that cefazolin is a valuable option for the treatment of MSSA IE, without differences in 1-year mortality or relapses compared with cloxacillin, and might be considered equally effective.

Therapeutic Options for Adult Patients With Persistent Methicillin-Susceptible Staphylococcus aureus Bacteremia: A Narrative Review

OBJECTIVE

To compare the efficacy of antimicrobial therapies used in the management of persistent methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia.

DATA SOURCES

A literature search using the PubMed database (inception to December 2022) was conducted using the search terms "Staphylococcus aureus bacteremia," "methicillin-susceptible Staphylococcus aureus bacteremia," "persistent methicillin-susceptible Staphylococcus aureus bacteremia," and "refractory methicillin-susceptible Staphylococcus aureus bacteremia ." In addition, therapeutic agents which could be used as treatment for MSSA including "nafcillin," "oxacillin," "cefazolin," "ceftaroline," "gentamicin," "rifampin," and "daptomycin" were also combined with the aforementioned search terms to capture data using these agents.

STUDY SELECTION/DATA EXTRACTION

Clinical data were limited to those published in the English language. Articles and abstracts were considered for inclusion in addition to ongoing trials identified through ClinicalTrials.gov.

DATA SYNTHESIS

A total of 78 articles were reviewed including 17 in vitro or animal model studies and 39 studies including patient data. The remaining 22 articles included guidelines, review articles, and editorials. Recent data evaluating use of dual β-lactam regimens for persistent MSSA bacteremia were limited to 8 case reports or case series.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

At present, there is little guidance on how to best manage patients with persistent MSSA bacteremia. This narrative review collates the available data to assist clinicians in selecting the best possible antimicrobial regimen when facing this clinical conundrum.

CONCLUSIONS

Modification of antimicrobial therapy, in conjunction with source control and infectious diseases consultation, may all be necessary to sterilize blood cultures in patients with persistent MSSA bacteremia.

Guidelines for Diagnosis and Management of Infective Endocarditis in Adults: A WikiGuidelines Group Consensus Statement

Importance

Practice guidelines often provide recommendations in which the strength of the recommendation is dissociated from the quality of the evidence.

Objective

To create a clinical guideline for the diagnosis and management of adult bacterial infective endocarditis (IE) that addresses the gap between the evidence and recommendation strength.

Evidence Review

This consensus statement and systematic review applied an approach previously established by the WikiGuidelines Group to construct collaborative clinical guidelines. In April 2022 a call to new and existing members was released electronically (social media and email) for the next WikiGuidelines topic, and subsequently, topics and questions related to the diagnosis and management of adult bacterial IE were crowdsourced and prioritized by vote. For each topic, PubMed literature searches were conducted including all years and languages. Evidence was reported according to the WikiGuidelines charter: clear recommendations were established only when reproducible, prospective, controlled studies provided hypothesis-confirming evidence. In the absence of such data, clinical reviews were crafted discussing the risks and benefits of different approaches.

Findings

A total of 51 members from 10 countries reviewed 587 articles and submitted information relevant to 4 sections: establishing the diagnosis of IE (9 questions); multidisciplinary IE teams (1 question); prophylaxis (2 questions); and treatment (5 questions). Of 17 unique questions, a clear recommendation could only be provided for 1 question: 3 randomized clinical trials have established that oral transitional therapy is at least as effective as intravenous (IV)-only therapy for the treatment of IE. Clinical reviews were generated for the remaining questions.

Conclusions and Relevance

In this consensus statement that applied the WikiGuideline method for clinical guideline development, oral transitional therapy was at least as effective as IV-only therapy for the treatment of IE. Several randomized clinical trials are underway to inform other areas of practice, and further research is needed.

Heartbreaking Decisions: The Dogma and Uncertainties of Antimicrobial Therapy in Infective Endocarditis

Infective endocarditis (IE) is a rare but increasingly prevalent disease with high morbidity and mortality, requiring antimicrobials and at times surgical intervention. Through the decades of healthcare professionals' experience with managing IE, certain dogmas and uncertainties have arisen around its pharmacotherapy. The introduction of new antimicrobials and novel combinations are exciting developments but also further complicate IE treatment choices. In this review, we provide and evaluate the relevant evidence focused around contemporary debates in IE treatment pharmacotherapy, including beta-lactam choice in MSSA IE, combination therapies (aminoglycosides, ceftaroline), the use of oral antimicrobials, the role of rifamycins, and long-acting lipoglycopeptides.

Prevalence of a cefazolin inoculum effect associated with blaZ gene types, and clinical outcomes among methicillin-susceptible Staphylococcus aureus blood isolates of patients with infective endocarditis

OBJECTIVES

A proportion of blaZ gene-positive methicillin-susceptible Staphylococcus aureus (MSSA) strains exhibits the cefazolin inoculum effect (CInE). Its clinical impact remains uncertain but could compromise the use of cefazolin in high-burden infections. To date, no study has been conducted in France or in Europe. We aimed to assess the prevalence of CInE and its association with blaZ beta-lactamase and S. aureus protein A (spa) types, and to assess the clinical outcomes in cefazolin-treated patients for infective endocarditis whose strain exhibited a CInE.

METHODS

This was a French single-center retrospective study of 51 MSSA strains from patients of the Nantes endocarditis prospective cohort, conducted between 2013 and 2018.

RESULTS

Cefazolin MIC₅₀ at high inoculum was 2 mg/L (IQR 1-2). CInE was found in 17.6 % of tested strains. Among blaZ-positive strains (n = 44), type A beta-lactamase was predominant (n = 25, 57 %). Thirty-seven S. aureus protein A (spa) types were found. No statistical association was shown between blaZ or spa types and CInE. CInE was neither associated with a higher rate of persistent bacteremia (25 % vs 56.3 %, p = 0.58) nor with clinical failure in patients treated with cefazolin, in comparison to patients with no CInE strain (25 % vs 56.3 %, p = 0.58).

CONCLUSION

The cefazolin inoculum effect was found in a substantial number of Staphylococcus aureus strains; however, minimum inhibitory concentrations remained globally low. CInE was not associated with a higher proportion of clinical failure on treatment.

A review of evidence, antimicrobial stability, and feasibility considerations for OPAT continuous infusion

Outpatient parenteral antimicrobial therapy (OPAT) has been widely used in clinical practice for many decades because of its associated cost savings, reductions in inpatient hospital days, and decreases in hospital-associated infections. Despite this long history, evolving practice patterns and new drug delivery devices continue to present challenges as well as opportunities for clinicians when designing appropriate outpatient antimicrobial regimens. One such change is the increasing use of extended and continuous infusion (CI) of antimicrobials to optimize the achievement of pharmacokinetic and pharmacodynamic targets. Elastomeric devices are also becoming increasingly popular in OPAT, including for the delivery of CI. In this article, we review the clinical evidence for CI in OPAT, as well as practical considerations of patient preferences, cost, and antimicrobial stability.

Staphylococcus aureus endocarditis: Identifying prognostic factors using a method derived from morbidity and mortality conferences

Objectives

Lethality of Staphylococcus aureus (Sa) infective endocarditis (IE) is high and might be due to yet unidentified prognostic factors. The aim of this study was to search for new potential prognostic factors and assess their prognostic value in SaIE.

Materials and methods

We used a two-step exploratory approach. First, using a qualitative approach derived from mortality and morbidity conferences, we conducted a review of the medical records of 30 patients with SaIE (15 deceased and 15 survivors), randomly extracted from an IE cohort database (NCT03295045), to detect new factors of possible prognostic interest. Second, we collected quantitative data for these factors in the entire set of SaIE patients and used multivariate Cox models to estimate their prognostic value.

Results

A total of 134 patients with modified Duke definite SaIE were included, 64 of whom died during follow-up. Of the 56 candidate prognostic factors identified at the first step, 3 had a significant prognostic value in multivariate analysis: the prior use of non-steroidal anti-inflammatory drugs [aHR 3.60, 95% CI (1.59-8.15), p = 0.002]; the non-performance of valve surgery when indicated [aHR 1.85, 95% CI (1.01-3.39), p = 0.046]; and the decrease of vegetation size on antibiotic treatment [aHR 0.34, 95% CI (0.12-0.97), p = 0.044].

Conclusion

We identified three potential SaIE prognostic factors. These results, if externally validated, might eventually help improve the management of patients with SaIE.

Current clinical practice in antibiotic treatment of Staphylococcus aureus bacteraemia: results from a survey in five European countries

OBJECTIVES

To determine clinical practice variation and identify knowledge gaps in antibiotic treatment of Staphylococcus aureus bacteraemia (SAB).

METHODS

A web-based survey with questions addressing antibiotic treatment of SAB was distributed through the ESGAP network among infectious disease specialists, clinical microbiologists and internists in Croatia, France, Greece, the Netherlands and the UK between July 2021 and November 2021.

RESULTS

A total number of 1687 respondents opened the survey link, of whom 677 (40%) answered at least one question. For MSSA and MRSA bacteraemia, 98% and 94% preferred initial monotherapy, respectively. In patients with SAB and non-removable infected prosthetic material, between 80% and 90% would use rifampicin as part of the treatment. For bone and joint infections, 65%-77% of respondents would consider oral step-down therapy, but for endovascular infections only 12%-32% would. Respondents recommended widely varying treatment durations for SAB with different foci of infection. Overall, 48% stated they used 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG-PET/CT) to guide antibiotic treatment duration. Persistent bacteraemia was the only risk factor for complicated SAB that would prompt a majority to extend treatment from 2 to 4-6 weeks.

CONCLUSIONS

This survey in five European countries shows considerable clinical practice variation between and within countries in the antibiotic management of SAB, in particular regarding oral step-down therapy, choice of oral antibiotic agents, treatment duration and use of 18F-FDG-PET/CT. Physicians use varying criteria for treatment decisions, as evidence from clinical trials is often lacking. These areas of practice variation could be used to prioritize future studies for further improvement of SAB care.

Staphylococcus aureus native mitral valve endocarditis associated with bed bug bites - A case report and review of the literature

Staphylococcus aureus is a leading cause of community acquired bacteremia and infective endocarditis. S. aureus is a part of the normal skin flora in approximately one third of the human population. Infective endocarditis due to S. aureus can cause several complications and is associated with increased mortality. A 48-year-old female with no significant medical history presented with S. aureus bacteremia and native mitral valve endocarditis. Multiple cutaneous skin lesions were identified, which she reported were due to recent bed bug bites. No source of infection was found except for the skin lesions. Her hospital course was complicated by pulmonary and cerebral septic emboli, left pleural empyema, and acute renal injury. We suspected the bed bug skin bites were the most likely source of bacteremia. Bed bugs carry many human pathogens but have not been shown to be a competent vector. We did not find any literature on endocarditis associated with bed bug bites; thus, our case will be a novel finding.

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.

Antistaphylococcal Penicillin vs Cefazolin for the Treatment of Methicillin-Susceptible Staphylococcus aureus Spinal Epidural Abscesses

Cefazolin is commonly used as an alternative to antistaphylococcal penicillins (ASPs) in treating methicillin-susceptible Staphylococcus aureus (MSSA) infections; however, no study has compared these agents in MSSA spinal epidural abscess (SEA). We describe our experience in managing MSSA SEA and compare the clinical efficacy of cefazolin with ASPs. This retrospective multicenter study reviewed 79 adult patients diagnosed with SEA between January 2006 and July 2020 using data collected from electronic health records and clinical microbiology laboratory databases. Forty-five patients received cefazolin, while 34 received ASPs. The total antibiotic duration was longer in the ASPs group but not statistically significant. There were no significant differences in treatment failure at week 6 vs week 12, 30-day vs overall mortality, or in 90-day recurrence rates between the treatment groups. Cefazolin was equally as effective as ASPs, and our findings suggest that it can be an alternative to ASPs in the treatment of MSSA SEA.