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

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.

Prospective assessment of the frequency of and risk factors for bleeding events in patients treated with cefazolin

PURPOSE

Major bleedings have been described with cefazolin. The objective was to determine the frequency of bleeding events in cefazolin-treated patients and to identify risk factors for these complications.

METHODS

Monocenter prospective observational study of all consecutive cefazolin-treated patients. Patients benefited from a daily clinical assessment of bleedings and a twice-a-week blood sampling including hemostasis. Bleedings were classified according to the International Society on Thrombosis and Hemostasis classification: major, clinically relevant non-major bleedings (CRNMB) and minor bleedings.

RESULTS

From September 2019 to July 2020, 120 patients were included, with a mean age of 59.4 (± 20.7) years; 70% of them (84/120) were men. At least 1 CRNMB or major bleeding were observed in 10% of the patients (12/120). Compared to patients with no or minor bleeding, patients with CRNMB or major bleeding were, upon start of cefazolin, more frequently hospitalized in an intensive care unit (7/12, 58.3%, vs. 12/108, 11.1%, P < 0.001, respectively) and receiving vitamin K antagonists (4/12, 33.3%, vs. 8/108, 7.4%, P = 0.019, respectively). After multivariate analysis, patients receiving vitamin K antagonists the day prior bleeding and/or treated for endocarditis were factors associated with an increased risk of CRNMB or major bleeding (odd ratio 1.36, confidence interval 95%, 1.06-1.76, P = 0.020 and 1.30, 1.06-1.61, P = 0.015, respectively).

CONCLUSIONS

Bleeding events associated with cefazolin treatment are frequent. Close clinical monitoring should be performed for patients treated for endocarditis and/or receiving vitamin K antagonists. Hemostasis work-up could be restricted to these patients.

Cephalotin Versus Dicloxacillin for the Treatment of Methicillin-Susceptible Staphylococcus aureus Bacteraemia: A Retrospective Cohort Study

BACKGROUND

First-line treatments for methicillin-susceptible S. aureus (MSSA) bacteraemia are nafcillin, oxacillin, or cefazolin. Regional shortages of these antibiotics force clinicians to use other options like dicloxacillin and cephalotin. This study aims to describe and compare the safety and efficacy of cephalotin and dicloxacillin for the treatment of MSSA bacteraemia.

METHODS

This retrospective study was conducted in a referral centre in Mexico City. We identified MSSA isolates in blood cultures from 1 January 2012 to 31 December 2022. Patients ≥ 18 years of age, with a first episode of MSSA bacteraemia, who received cephalotin or dicloxacillin as the definitive antibiotic treatment, were included. The primary outcome was in-hospital all-cause mortality.

RESULTS

We included 202 patients, of which 48% (97/202) received cephalotin as the definitive therapy and 52% (105/202) received dicloxacillin. In-hospital all-cause mortality was 20.7% (42/202). There were no differences in all-cause in-hospital mortality between patients receiving cephalotin or dicloxacillin (20% vs. 21%, p = 0.43), nor in 30-day all-cause mortality (14% vs. 18%, p = 0.57) or 90-day all-cause mortality (24% vs. 22%, p = 0.82). No severe adverse reactions were associated with either antibiotic.

CONCLUSIONS

Cephalotin and dicloxacillin were equally effective for treating MSSA bacteraemia, and both showed an adequate safety profile.

Epidemiology and impact of methicillin-sensitive Staphylococcus aureus with β-lactam antibiotic inoculum effects in adults with cystic fibrosis

Staphylococcus aureus is the most prevalent cystic fibrosis (CF) pathogen. Several phenotypes are associated with worsened CF clinical outcomes including methicillin-resistance and small-colony-variants. The inoculum effect (IE) is characterized by reduced β-lactam susceptibility when assessed at high inoculum. The IE associates with worse outcomes in bacteremia and other high-density infections, and may therefore be relevant to CF. The prevalence of IE amongst a CF cohort (age ≥18 years), followed from 2013 to 2016, was investigated. Yearly methicillin-sensitive S. aureus (MSSA) isolates were screened at standard (5 × 105 CFU/mL) and high (5 × 107 CFU/mL) inoculum against narrow-spectrum anti-Staphylococcal β-lactams and those with anti-pseudomonal activity common to CF. A ≥ 4-fold increase in minimum inhibitory concentration between standard and high inoculum defined IE. Isolates underwent blaZ sequencing and genotyping and were compared against published genomes. Fifty-six percent (99/177) of individuals had MSSA infection. MSSA was observed at ≥105 CFU/mL in 44.8% of entry sputum samples. The prevalence of the IE was 25.0%-cefazolin; 13.5%-cloxacillin; 0%-meropenem; 1.0%-cefepime; 5.2%-ceftazidime; and 34.4%-piperacillin-tazobactam amongst baseline MSSA isolates assessed. blaZ A associated with cefazolin IE (P = 0.0011), whereas blaZ C associated with piperacillin-tazobactam IE (P < 0.0001). Baseline demographics did not reveal specific risk factors for IE-associated infections, nor were long-term outcomes different. Herein, we observed the IE in CF-derived MSSA disproportionally for cefazolin and piperacillin-tazobactam and this phenotype strongly associated with underlying blaZ genotype. The confirmation of CF being a high density infection, and the identification of high prevalence of MSSA with IE in CF supports the need for prospective pulmonary exacerbation treatment studies to understand the impact of this phenotype.

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.

Characterization of Brazilian green propolis as a photosensitizer for LED light-induced antimicrobial photodynamic therapy (aPDT) against methicillin-resistant Staphylococcus aureus (MRSA) and Vancomycin-intermediate Staphylococcus aureus (VISA)

Staphylococcus aureus is the primary cause of skin and soft tissue infections. Its significant adaptability and the development of resistance are the main factors linked to its spread and the challenges in its treatment. Antimicrobial photodynamic therapy emerges as a promising alternative. This work aimed to characterize the antimicrobial photodynamic activity of Brazilian green propolis, along with the key bioactive compounds associated with this activity. Initially, a scanning spectrometry was conducted to assess the wavelengths with the potential to activate green propolis. Subsequently, reference strains of methicillin-resistant Staphylococcus aureus (MRSA ATCC 43300) and vancomycin-intermediate Staphylococcus aureus (VISA ATCC 700699) were exposed to varying concentrations of green propolis: 1 µg/mL, 5 µg/mL, 10 µg/mL, 50 µg /mL and 100 µg/mL and were stimulated by blue, green or red LED light. Finally, high-performance liquid chromatography coupled with a diode array detector and tandem mass spectrometry techniques, along with classic molecular networking analysis, was performed to identify potential bioactive molecules with photodynamic activity. Brazilian green propolis exhibits a pronounced absorption peak and heightened photo-responsiveness when exposed to blue light within the range of 400 nm and 450 nm. This characteristic reveals noteworthy significant photodynamic activity against MRSA and VISA at concentrations from 5 µg/mL. Furthermore, the propolis comprises compounds like curcumin and other flavonoids sourced from flavone, which possess the potential for photodynamic activity and other antimicrobial functions. Consequently, Brazilian green propolis holds promise as an excellent bactericidal agent, displaying a synergistic antibacterial property enhanced by light-induced photodynamic effects.

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.

Variation Among Infectious Diseases Pharmacists for the Treatment of Staphylococcus aureus Bacteremia

Introduction: Staphylococcus aureus bacteremia (SAB) remains complex, in that optimal treatment for patients, including complicated or persistent infection, remains unclear. Two recent surveys have demonstrated practice variations in SAB among infectious diseases (ID) physicians. Objectives: The purpose of this survey was to examine practice variations in SAB among ID pharmacists. Methods: A thirty-five-question survey was electronically distributed to the American College of Clinical Pharmacy (ACCP) Infectious Diseases Practice and Research Network (IDPRN) in Fall 2019 to determine differences in SAB management. Data were analyzed utilizing Pearson's Chi-Square or Fisher's Exact Test. Results: A total of 106 ID pharmacists responded. Only 28% of pharmacists practiced at hospitals with mandatory ID consultation for SAB. A majority (75%) had rapid diagnostic technology (RDT) for identifying SABSI, but 32% of those facilities with RDT did not notify pharmacy with results. Anti-staphylococcal penicillins were preferred for MSSA blood stream infections (BSI) in patients with central nervous system infection and endocarditis, whereas cefazolin was favored for other MSSA BSI. For persistent MRSA BSI, 34% selected daptomycin alone while 38% elected to combine daptomycin and ceftaroline. Pharmacists at hospitals less than 500 beds were more likely to use daptomycin, while those at larger hospitals were more likely to use daptomycin and ceftaroline for persistent MRSA BSI (P < .05). Conclusions: A survey of ID pharmacists showed variation in the management of SABs, as well as the definition and treatment of persistent SAB. Mandatory ID consultation and RDT use to improve SAB management have not been optimized.

Targeting Staphylococcus aureus dominated skin dysbiosis in actinic keratosis to prevent the onset of cutaneous squamous cell carcinoma: Outlook for future therapies?

Cutaneous squamous cell carcinoma (cSCC) and its premalignant precursor, actinic keratosis (AK), present a global health burden that is continuously increasing despite extensive efforts to promote sun safety. Chronic UV exposure is a recognized risk factor for the development of AK and cSCC. However, increasing evidence suggests that AK and cSCC is also associated with skin microbiome dysbiosis and, in particular, an overabundance of the bacterium Staphylococcus aureus (S. aureus). Studies have shown that S. aureus-derived toxins can contribute to DNA damage and lead to chronic upregulation of proinflammatory cytokines that may affect carcinogenesis. Eradication of S. aureus from AK lesions and restoration of a healthy microbiome may therefore represent a therapeutic opportunity to alter disease progression. Whilst antibiotics can reduce the S. aureus load, antibiotic resistant S. aureus pose an increasing global public health threat. The use of specific topically delivered probiotics has been used experimentally in other skin conditions to restore eubiosis, and could therefore also present a non-invasive treatment approach to decrease S. aureus colonization and restore a healthy skin microbiome on AK lesions. This article reviews mechanisms by which S. aureus may contribute to cutaneous carcinogenesis, and discusses hypotheses and theories that explore the therapeutic potential of specific bacterial species which compete with S. aureus in an attempt to restore microbial eubiosis in skin.

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.

Frequency of pharmacological target attainment with flucloxacillin and cefazolin in invasive methicillin-susceptible Staphylococcus aureus infection: a prospective cohort study in hospitalized patients

BACKGROUND

The proportion of patients with invasive methicillin-susceptible Staphylococcus aureus (MSSA) infection who achieve target concentrations of flucloxacillin or cefazolin with standard dosing regimens is uncertain. This study measured drug concentrations in a prospective cohort of patients with invasive S. aureus infections to determine the frequency of target concentration attainment, and risk factors for failure to achieve target concentrations.

PATIENTS AND METHODS

Unbound flucloxacillin and cefazolin plasma concentrations were measured at the midpoint between intravenous doses. Adequate and optimal targets were defined as an unbound plasma concentration of ≥1 and ≥2 times the minimum inhibitory concentration (MIC) (flucloxacillin 0.5 mg/L, cefazolin 2 mg/L), respectively (50%fT_≥1MIC, 50%fT_≥2MIC).

RESULTS

There were 50 patients in each of the flucloxacillin and cefazolin groups. Eighty-five (85%) patients met the target of 50%fT_≥2MIC and 95 (95%) patients met the target of 50%fT_≥1MIC. The median unbound flucloxacillin concentration was 2.6 mg/L [interquartile range (IQR) 1.0-8.1]. The median unbound cefazolin concentration was 15.4 mg/L (IQR 8.8-28.2). A higher proportion of patients in the flucloxacillin group failed to achieve the optimal target compared with the cefazolin group [13 (26%) vs 2 (4%); P=0.002]. Younger age and higher creatinine clearance were associated with lower plasma concentrations.

CONCLUSIONS

Standard dosing of flucloxacillin and cefazolin in the treatment of invasive MSSA infections may not achieve target plasma concentrations for a subgroup of patients. Measuring drug concentrations identifies this subgroup and facilitates dose individualization.

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.

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.

Cefazolin prophylaxis in spine surgery: patients are frequently underdosed and at increased risk for infection

BACKGROUND CONTEXT

Perioperative antibiotics are critical in reducing the risk of postoperative spine infections. However, the efficacy and optimal weight-based prophylactic cefazolin dosing is unclear.

PURPOSE

To determine (1) if inadequate weight-based prophylactic dosing of cefazolin affects infection rates after spinal fusions, and (2) identify the optimal dosing of cefazolin.

STUDY DESIGN/SETTING

Single center retrospective cohort PATIENT SAMPLE: Patients undergoing posterior cervical or lumbar spinal fusion between January 2000 and October 2020 OUTCOME MEASURES: Postoperative surgical site infection status METHODS: Patients were grouped based on our institutionally derived dosing adequacy standards, 1 g for <60 kg, 2 g for 60 to 120 kg, and 3 g for >120 kg. Univariate comparisons and multivariate regressions identified the effect of inadequate dosing on infection rate. Patients were subsequently regrouped into cefazolin dose (grams) administered and logistic regression and receiver operating characteristic curves were compiled to determine the probability of infection based on cefazolin dose and patient weight. Alpha was set at 0.05.

RESULTS

A total of 2,643 patients met inclusion criteria and 95 infections (3.6%) were identified. The infection rate was higher in the inadequate dosing group (5.86% vs. 2.58%, p<.001). Adequate dosing was a predictor of decreased infections after lumbar fusion (OR: 0.43, p<.001), but not posterior cervical fusions (OR: 0.47, p=.065). Patients were subsequently regrouped into 1 g or 2 g of cefazolin administered resulting in a 5.01% and 2.77% infection rate, respectively (p=.005). The area under the curve (AUC) and 95% confidence interval for one (0.850 [0.777-0.924]) and two (0.575 [0.493-0.657]) g of cefazolin demonstrated lower infection rates for patients given 2 g cefazolin.

CONCLUSIONS

Patients receiving an inadequate weight-based dose of preoperative cefazolin had an increased risk of infection following spinal fusion surgery. Two grams prophylactic cefazolin significantly reduces the likelihood of infection.

Staphylococcus aureus in Non-Cystic Fibrosis Bronchiectasis: Prevalence and Genomic Basis of High Inoculum Beta-Lactam Resistance

Rationale The pathobiology of Staphylococcus aureus in non-cystic fibrosis bronchiectasis (nCFB) is poorly defined. When present at high density or "inoculum", some methicillin-sensitive S. aureus (MSSA) can inefficiently degrade anti-Staphylococcal beta-lactam antibiotics via BlaZ penicillinases (termed, the inoculum effect). Given the high burden of organisms in bronchiectatic airways, this is particularly relevant. Objectives Drawing from a prospectively-collected biobank, we sought to understand the prevalence, natural history, potential for transmission, and antibiotic resistance profiles amongst nCFB-derived MSSA isolates. Methods All individuals attending a regional consultancy nCFB clinic with sputum collected between 1981-2017 were considered, and those with ≥1 S. aureus-positive culture comprised the cohort. Each individual's most recent biobank isolate was subjected to whole genome sequencing (including the blaZ gene), antibacterial susceptibility testing, and comparative beta-lactam testing at standard (5 x 105CFU/mL) and high (5 x 107CFU/mL) inoculum to assess for the inoculum, and pronounced inoculum effect (IE and pIE, respectively). Results Seventy-four of 209 (35.4%) individuals had ≥1 sputum sample(s) with S. aureus (68 MSSA, 6 MRSA). Those with S. aureus infection were more likely to be female. Amongst 60/74 MSSA isolates subjected to WGS, no evidence of transmission was identified, although specific MLST types were prevalent including ST-1, ST-15, ST-30, and ST-45. Antibiotic resistance was uncommon except for macrolides (~20%). Amongst the 60 MSSA, prevalence of IE and pIE, respectively, were observed to be drug specific; meropenem (0%, 0%), cefepime (3%, 5%), ceftazidime (8%, 0%), cloxacillin (12%, 0%), cefazolin (23%, 0%) and piperacillin-tazobactam (37%, 17%). The cefazolin IE associated with blaZ type A (p<0.01) and ST-30 (p<0.01), whereas the piperacillin-tazobactam IE associated with type C blaZ (p<0.001) and ST-15 (p<0.05). Conclusions S. aureus infection was common, although no evidence of transmission was apparent in our nCFB cohort. While routine susceptibility testing did not identify significant resistance, inoculum-related resistance was found to be relevant for commonly used nCFB antibiotics including cefazolin and piperacillin-tazobactam. Given previous associations between IEs and negative patient outcomes, further work is warranted to understand how this phenotype impacts nCFB disease progression.

A Lateral Flow Test for Staphylococcus aureus in Nasal Mucus Using a New DNAzyme as the Recognition Element

Detection of pathogenic bacteria in complex biological matrices remains a major challenge. Herein, we report the selection and optimization of a new DNAzyme for Staphylococcus aureus (SA) and the use of the DNAzyme to develop a simple lateral flow device (LFD) for detection of SA in nasal mucus. The DNAzyme was generated by in vitro selection using a crude extra/intracellular mixture derived from SA, which could be used directly for simple solution or paper-based fluorescence assays for SA. The DNAzyme was further modified to produce a DNA cleavage fragment that acted as a bridging element to bind DNA-modified gold nanoparticles to the test line of a LFD, producing a simple colorimetric dipstick test. The LFD was evaluated with nasal mucus samples spiked with SA, and demonstrated that SA detection was possible in minutes with minimal sample processing.

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.

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.

Continuous Versus Intermittent Infusion of Vancomycin and the Risk of Acute Kidney Injury in Critically Ill Adults: A Systematic Review and Meta-Analysis

OBJECTIVES

Critically ill patients routinely receive vancomycin as empiric antibiotic therapy. A continuous infusion administration strategy may be superior to intermittent infusion by minimizing peak concentrations and variability thereby optimizing safety. We performed a systematic review and meta-analysis to investigate the impact of vancomycin infusion strategy on acute kidney injury in critically ill adults.

DATA SOURCES

A systematic search of MEDLINE, CINAHL, Web of Science, International Pharmaceutical Abstracts, and Google Scholar was undertaken.

STUDY SELECTION

We included randomized controlled trials and observational studies evaluating acute kidney injury in critically ill adults comparing vancomycin administered by intermittent and continuous infusion. Secondary outcomes included mortality and pharmacokinetic target attainment.

DATA EXTRACTION

Eleven studies were identified for analysis with baseline demographics, endpoints, protocol definitions, and outcomes extracted.

DATA SYNTHESIS

When compared with intermittent infusion, continuous infusion was associated with a reduction in acute kidney injury in critically ill adults (odds ratio, 0.47; 95% CI, 0.34-0.65) and a 2.6 greater odds of pharmacokinetic target attainment (odds ratio, 2.63; 95% CI, 1.52-4.57). No difference in mortality was observed (odds ratio, 1.04; 95% CI, 0.80-1.35).

CONCLUSIONS

When administered via a continuous infusion, vancomycin is associated with a 53% reduction in the odds of acute kidney injury and a 2.6-fold higher odds of pharmacokinetic target attainment when compared with intermittent infusion without influencing overall mortality.

Effect of the vancomycin minimum inhibitory concentration on clinical outcomes in patients with methicillin-susceptible Staphylococcus aureus bacteraemia: a systematic review and meta-analysis

OBJECTIVE

The use of the vancomycin minimum inhibitory concentration (MIC) as a prognostic predictor in patients with methicillin-susceptible Staphylococcus aureus (MSSA) has been debated in the last decade. We performed a systematic review and meta-analysis to investigate whether an elevated vancomycin MIC is associated with a worse prognosis for patients with MSSA bacteraemia.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

PubMed, Embase and the Cochrane Library were searched from inception to December 2019.

ELIGIBILITY CRITERIA

Randomised controlled trials or observational studies were considered eligible if they provided clinical outcomes of patients with MSSA bacteraemia, stratified by vancomycin MIC.

DATA SYNTHESIS

Primary outcome was mortality. Secondary outcomes included septic thrombophlebitis, persistent bacteraemia and complicated bacteraemia. Pooled ORs and 95% CIs were calculated. Subgroup analyses included the susceptibility testing method.

RESULTS

Fifteen observational studies were included. Bacteraemia due to MSSA isolates with high vancomycin MICs was associated with higher mortality than isolates with low MICs (OR 1.44; 95% CI 1.12 to 1.84; I²=40.3%). Additionally, significantly greater septic thrombophlebitis (OR 3.16; 95% CI 1.11 to 9.00; I²=58.6%) and a trend towards more persistent bacteraemia (OR 1.79; 95% CI 0.97 to 3.31; I²=0%) were observed in patients with high vancomycin MICs than in patients with low MICs. Differences in complicated bacteraemia were not significant. Similar findings were obtained in subgroup analyses using Etest. However, significant differences in outcomes were not observed between the high and low vancomycin MICs detected using broth microdilution.

CONCLUSION

The available data suggest an association between elevated vancomycin MICs detected using Etest and adverse clinical outcomes for patients with MSSA bacteraemia. Future studies should validate these findings and explore the potential mechanisms.

PROSPERO REGISTRATION NUMBER

CRD42018090547.

Prolonged cefazolin course for treatment of methicillin susceptible staphylococcus species infections and the impact on the emergence of multidrug-resistant bacteria during cloxacillin shortage

OBJECTIVES

To describe the efficacy and safety of prolonged cefazolin course for Staphylococcus infection and the emergence of multidrug-resistant bacteria carriage after treatment.

METHODS

Monocentric retrospective cohort study of patients hospitalized for blood stream infections (BSI) and osteoarticular infections (OAI) by methicillin susceptible staphylococcal species treated with cefazolin from January 2015 to July 2017. Rectal and nasal swabs were performed at cefazolin initiation and end of treatment to detect respectively methicillin resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase (ESBL) producing bacteria.

RESULTS

Fifty-eight patients were included, 41 had a bacteremia including 22 endocarditis and 22 OAI. Mean duration of treatment was 21.5 days at a mean daily dose of 6.5g/d. Fifty-five (94.5%) received combination therapy. Fifty-two (89.7%) of patients achieved bacteriological cure. Four patients were ESBL carriers at inclusion. No additional ESBL or MRSA were detected by end of treatment.

CONCLUSION

Cefazolin appears as an effective and safe treatment for BSI or osteoarticular infection and does not appear to select MRSA or ESBL.

Therapy of Staphylococcus aureus bacteremia: Evidences and challenges

Staphylococcus aureus bacteremia (SAB) is still a daily challenge for clinicians. Despite all efforts, the associated mortality and morbidity has not significantly improved in the last 20 years. The available evidence suggests that adherence to some quality-of-care indicators with regard to clinical management is important in improving the outcome of patients, but it is lower than desired in many hospitals; as such, management of patients with SAB by infectious diseases specialists has been demonstrated to contribute in the reduction of the mortality rate of these patients. In this article, the most relevant clinical studies published over the last few years evaluating the efficacy and safety of alternative drugs for the treatment of SAB are reviewed. However, classic drugs are still used in a high proportion of patients because the promising results obtained from in vivo and in vivo studies with these alternative drugs have not translated as frequently as expected into evident superiority in clinical studies. Nevertheless, some data suggest that certain alternatives may offer advantages in specific situations. Overall, an individualised and expert approach is needed in order to decide the best treatment according to the source, severity, complications, patients' features and microbiological data.

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.

Comparison of penicillins (penicillin G and ampicillin) and cefazolin as a definitive therapy against penicillin-susceptible Staphylococcus aureus (PSSA) bacteremia in Japan: a retrospective cohort study

OBJECTIVES

Cefazolin has been the first-choice drug to treat penicillin-susceptible Staphylococcus aureus (PSSA) bacteremia, because oxacillin and nafcillin are not approved in Japan. Since February 2019, cefazolin supply is stagnant in Japan because of possible contamination issues. To look for cefazolin alternatives that can be used as a definitive therapy, we evaluated the usefulness of penicillins (penicillin G and ampicillin) against PSSA bacteremia.

METHODS

A retrospective cohort study of patients with methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia was conducted between January 2012 and September 2017. MSSA was determined according to the Clinical and Laboratory Standards Institute guidelines. PSSA was defined as S. aureus with penicillin G minimum inhibitory concentration of ≤0.03 mg/L without using the zone edge test or blaZ PCR.

RESULTS

Of the 280 patients with MSSA bacteremia enrolled, and 138 (49.3%) was PSSA. Of the 44 patients who met the inclusion criteria, 11 were administered penicillins (penicillin G, n = 3 and ampicillin, n = 8) and 33 with cefazolin. Although the patients in the two groups had similar demographics, those in the penicillins group had significantly lower median Charlson score [interquartile range] than those in the cefazolin group (0[0-1] vs 1[0-4], p = 0.033). The two groups showed no significant differences regarding adverse events and bacteremia recurrence. None of the patients in the penicillins group died; however, 5 (15.2%) patients in the cefazolin group showed a 30-days mortality.

CONCLUSION

Penicillins can be useful as a definitive therapy against PSSA bacteremia with stable condition, and they can be an alternative to cefazolin.

Cefazolin Versus Anti-Staphylococcal Penicillins for the Treatment of Patients with Methicillin-Susceptible Staphylococcus aureus Infection: A Meta-Analysis with Trial Sequential Analysis

INTRODUCTION

Methicillin-susceptible Staphylococcus aureus (MSSA) is a common cause of infection in humans. Beta-lactam antibiotics are the preferred agents, with anti-staphylococcal penicillins (ASPs) or the first-generation cephalosporin, cefazolin, favored by clinicians. Recent studies comparing the two strategies suggest similar outcomes between the agents. The purpose of this meta-analysis was to explore differences between cefazolin and ASPs for the treatment of MSSA infections.

METHODS

We performed a meta-analysis with trial sequential analysis (TSA) of observational or cohort studies using a random-effects model. Two blinded reviewers independently assessed studies for inclusion, risk of bias, and data extraction. The primary outcome was all-cause mortality. Secondary outcomes included clinical failure, infection recurrence, and antibiotic discontinuation due to adverse events. Subgroup analyses were conducted for the primary outcome by type of ASP, studies with a high percentage of deep-seated infections, and studies of low to moderate risk of bias.

RESULTS

After performing a comprehensive search of the literature, and screening for study inclusion, 19 studies (13,390 patients) were included in the final meta-analysis. Fifteen of the 19 studies (79%) were judged as having a low or moderate risk of bias. Use of cefazolin was associated with lower all-cause mortality [odds ratio (OR) 0.71, 95% confidence interval (CI) 0.56-0.91, p = 0.006, I2 = 28%], clinical failure (OR 0.55, 95% CI 0.41-0.74, p < 0.001, I2 = 0%), and antibiotic discontinuation due to adverse events (OR 0.25, 95% CI 0.16-0.39, p < 0.001, I2 = 23%). Infection recurrence was higher in the cefazolin patients (OR 1.41, 95% CI 1.04-1.93, p = 0.03, I2 = 0%).

CONCLUSION

This meta-analysis demonstrated that the use of cefazolin was associated with significant reductions in all-cause mortality, clinical failure, and discontinuation due to adverse events, but was associated with an increased risk of infection recurrence.

FUNDING

University of Florida Open Access Publishing Fund funded the Rapid Service Fees.

TRIAL REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews (study ID: CRD42018106442).

Advances in the therapy of bacterial bloodstream infections

BACKGROUND

Advances in the diagnostic and therapeutic management of patients with bloodstream infections (BSIs) have been achieved in the last years, improving clinical outcome. However, mortality associated with some pathogens, such as Staphylococcus aureus and Enterococcus spp., is still high. In addition, the spread of antibiotic resistance, mainly among Gram-negative bacteria, reduces treatment options in some circumstances. Therefore, interest in new drugs, combination regimens and optimal dosing schedules is rising.

OBJECTIVES

Our aim is to summarize the current evidence on available antibiotic regimens for patients with bacterial BSI, focusing on drug choice, combination regimens and optimal dosing schedules. We selected bacteria that are difficult to manage because of virulence factors (i.e. methicillin-susceptible S. aureus), tolerance to antibiotic activity (i.e. Enterococcus faecalis), and/or susceptibility patterns (i.e. methicillin-resistant S. aureus, vancomycin-resistant enterococci, carbapenem-resistant Enterobacteriaceae, multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Acinetobacter baumannii).

SOURCES

MEDLINE search with English language and publication in the last 5 years as limits.

CONTENT AND IMPLICATIONS

The literature gaps on the use of new drugs, the uncertainties regarding the use of combination regimens, and the need to optimize dosing schedules in some circumstances (e.g. augmented renal clearance, renal replacement therapy, high inoculum BSI sources, and isolation of bacteria showing high MICs) have been revised.

Interventions to treat methicillin-susceptible Staphylococcus aureus bacteremia: many methodological concerns

The aim of this letter was to point out some methodological concerns about an article written by Shi et al. and published in the journal. There is an increasing trend in the isolation of Methicillin-susceptible Staphylococcus aureus bacteremia and a variety of questions regarding the best therapy to treat this condition. These concerns might lead to selection, publication and information bias that prevent the generalization and application of these results in our clinical practice.

In vitro bactericidal activity of amoxicillin combined with different cephalosporins against endocarditis-associated Enterococcus faecalis clinical isolates

Background

The 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.

Objectives

To evaluate in vitro the bactericidal activity of the combination of amoxicillin with different cephalosporins including cefazolin.

Methods

Combinations 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.

Results

The 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.

Conclusions

The combination amoxicillin/cefazolin is as synergistic and bactericidal in vitro as amoxicillin/cefotaxime or amoxicillin/ceftriaxone against E. faecalis.

Does the Beta-Lactam Matter? Nafcillin versus Cefazolin for Methicillin-Susceptible Staphylococcus aureus Bloodstream Infections

BACKGROUND

Antistaphylococcal penicillins have historically been regarded as the drugs of choice for methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections (BSI). However, recent outcomes data compared to cefazolin treatment are conflicting.

OBJECTIVE

This study compared treatment failure and adverse effects associated with nafcillin and cefazolin for MSSA BSI.

METHODS

Adult inpatients with MSSA BSI between January 1, 2009 and August 31, 2015 were included in this retrospective cohort study if they received ≥72 h of nafcillin or cefazolin as directed therapy after no more than 72 h of any empiric therapy. The primary composite endpoint was treatment failure defined by clinician documentation, 30-day recurrence of infection, all-cause 30-day in-hospital mortality, or loss to follow-up. Secondary outcomes included antibiotic-related acute kidney injury (AKI), acute interstitial nephritis (AIN), hepatotoxicity, and rash.

RESULTS

Among 157 patients, 116 (73.9%) received nafcillin and 41 (26.1%) received cefazolin. The baseline characteristics were similar except cefazolin-treated patients had higher APACHE II scores and more frequent renal dysfunction. No difference in the composite treatment failure outcome (28.4 vs. 31.7%; p = 0.69) was detected between the nafcillin and cefazolin groups, respectively. In a sensitivity analysis excluding patients without known follow-up, there was no significant difference of treatment failure. AKI, AIN, hepatotoxicity, and rash were all numerically more frequent among nafcillin-treated patients.

CONCLUSIONS

Among nafcillin- or cefazolin-treated patients with MSSA BSI, there was no significant difference in treatment failure. Observing more frequent presumptive adverse effects associated with nafcillin receipt, future prospective studies evaluating cefazolin appear warranted.

Cefazolin versus anti-staphylococcal penicillins for the treatment of patients with Staphylococcus aureus bacteraemia

BACKGROUND

For patients with bacteraemia caused by methicillin-sensitive Staphylococcus aureus anti-staphylococcal penicillins (ASPs) or cefazolin are agents of choice. While ASPs are potentially nephrotoxic, cefazolin may be less effective in some S. aureus strains due to an inoculum effect.

OBJECTIVES

To perform a systematic literature review and meta-analysis assessing current evidence comparing cefazolin with ASPs for patients with S. aureus bacteraemia (SAB).

METHODS

We searched MEDLINE, ISI Web of Science (Science Citation Index Expanded) and the Cochrane Database as well as clinicaltrials.gov from inception to 26 June 2018. All studies investigating the effects of cefazolin versus ASP in patients with methicillin-sensitive SAB were eligible for inclusion regardless of study design, publication status or language. Additional information was requested by direct author contact. A meta-analysis to estimate relative risks (RRs) with the corresponding 95% confidence intervals (CIs) was performed. Statistical heterogeneity was estimated using I². The primary endpoint was 90-day all-cause mortality. The Newcastle-Ottawa Scale (NOS) and Grading of Recommendations Assessment, Development and Evaluation (GRADE) were used for study and data quality assessment.

RESULTS

Fourteen non-randomized studies were included. Seven reported the primary endpoint (RR 0.71 (0.50, 1.02), low quality of evidence). Cefazolin treatment may be associated with lower 30-day mortality rates (RR 0.70 (0.54, 0.91), low quality of evidence) and less nephrotoxicity (RR 0.36 (0.21, 0.59), (low quality of evidence)). We are uncertain whether cefazolin and ASP differ regarding treatment failure/relapse as the quality of the evidence has been assessed as very low (RR of 0.84 (0.59, 1.18)). For patients with endocarditis (RR 0.71 (0.12, 4.05)) or abscesses (RR 1.17 (0.30, 4.63)), cefazolin treatment may be associated with equal 30-day and 90-day mortality (low quality of evidence).

CONCLUSIONS

Cefazolin seemed to be at least equally as effective as ASPs while being associated with less nephrotoxicity.

Evolution of haemostatic parameters and risk of bleeding during treatment with cefazolin

In 2017, five cases of severe haemorrhages during treatment with cefazolin occurred in France. The aim of this study was to assess the risk of haemorrhage related to treatment with cefazolin by evaluating haemostatic parameters and bleeding events. A retrospective study was conducted from January 2016 to December 2017. Two populations were analysed: (i) overall population, which included all patients treated with cefazolin during this period and (ii) coagulation study population, which included all patients treated with cefazolin with available coagulation parameters (activated partial thromboplastin time (aPTT) and international normalised ratio (INR) at baseline and at the end of treatment or EoT). Values of either aPTT or INR at baseline and at EoT were compared. Cases of severe haemorrhages were reported and correlated with values of aPTT and INR. Overall, 132 patients received cefazolin and 59/132 (45%) were included in the coagulation study group. A significant increase of median aPTT was observed from baseline to EoT (39.5 and 44.3 sec; p = 0.004, respectively). Overall, severe haemorrhage occurred in 7/132 (5%) patients. Coagulation parameters were available in three of them, and no correlation was observed between bleeding events and aPTT increase. This study showed that bleeding is probably more frequent than ever reported before during cefazolin treatment. The significant increase of aPTT observed during cefazolin treatment was not correlated with risk of haemorrhage. Further studies are needed to explore the possible physio-pathological pathways behind the modification of haemostatic parameters and risk of haemorrhage.