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

Deep-penetration functionalized cuttlefish ink nanoparticles for combating wound infections with synergetic photothermal-immunologic therapy

The challenge of wound infections post-surgery and open trauma caused by multidrug-resistant bacteria poses a constant threat to clinical treatment. As a promising antimicrobial treatment, photothermal therapy can effectively resolve the problem of drug resistance in conventional antibiotic antimicrobial therapy. Here, we report a deep-penetration functionalized cuttlefish ink nanoparticle (CINP) for photothermal and immunological therapy of wound infections. CINP is decorated with zwitterionic polymer (ZP, namely sulfobetaine methacrylate-methacrylate copolymer) to form CINP@ZP nanoparticles. Natural CINP is found to not only exhibit photothermal destruction of methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli), but also trigger macrophages-related innate immunity and enhance their antibacterial functions. The ZP coating on the surface of CINP enables nanoparticles to penetrate into deeply infected wound environment. In addition, CINP@ZP is further integrated into the thermosensitive Pluronic F127 gel (CINP@ZP-F127). After in situ spraying gel, CINP@ZP-F127 is also documented notable antibacterial effects in mice wound models infected with MRSA and E. coli. Collectively, this approach combining of photothermal therapy with immunotherapy can promote delivery efficiency of nanoparticles to the deep foci of infective wounds, and effectively eliminate wound infections.

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.

Severe atypical Lemierre syndrome caused by methicillin-sensitive Staphylococcus aureus: Two pediatric case reports

BACKGROUND

Lemierre syndrome is typically associated with ear, nose, and throat (ENT) infections caused by Fusobacterium necrophorum. Since 2002, cases of atypical Lemierre-like syndrome secondary to Staphylococcus aureus have been reported.

CASES

We report two pediatric cases of atypical Lemierre syndrome with a similar presentation: exophthalmia, absence of pharyngitis, metastatic lung infection, and intracranial venous sinus thrombosis. Both patients had a favorable outcome following treatment with antibiotics, anticoagulation, and corticosteroids.

CONCLUSION

Regular therapeutic monitoring of antibiotic levels helped to optimize antimicrobial treatment in both cases.

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.

Pre-surgical Nasal Decolonization of Staphylococcus aureus: A Health Technology Assessment

BACKGROUND

Staphylococcus aureus (S. aureus) is the most common cause of surgical site infections, and the nose is the most common site for S. aureus colonization. Pre-surgical (in the days prior to surgery) nasal decolonization of S. aureus may reduce the bacterial load and prevent the organisms from being transferred to the surgical site, thus reducing the risk of surgical site infection. We conducted a health technology assessment of nasal decolonization of S. aureus (including methicillin-susceptible and methicillin-resistant strains) with or without topical antiseptic body wash to prevent surgical site infection in patients undergoing scheduled surgery, which included an evaluation of effectiveness, safety, cost-effectiveness, the budget impact of publicly funding nasal decolonization of S. aureus, and patient preferences and values.

METHODS

We performed a systematic literature search of the clinical evidence to retrieve systematic reviews and selected and reported results from one review that was recent, of high quality, and relevant to our research question. We complemented the chosen systematic review with a literature search to identify randomized controlled trials published since the systematic review was published in 2019. We used the Risk of Bias in Systematic Reviews (ROBIS) tool to assess the risk of bias of each included systematic review and the Cochrane risk-of-bias tool for randomized controlled trials to assess the risk of bias of each included primary study. We assessed the quality of the body of evidence according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Working Group criteria. We performed a systematic economic literature search and conducted both cost-effectiveness and cost-utility analyses using a decision-tree model with a 1-year time horizon from the perspective of Ontario's Ministry of Health. We also analyzed the budget impact of publicly funding nasal decolonization of S. aureus in pre-surgical patients in Ontario. To contextualize the potential value of nasal decolonization, we spoke with people who had recently undergone surgery, some of whom had received nasal decolonization, and one family member of a person who had recently had surgery. We also engaged participants through an online survey.

RESULTS

We included one systematic review and three randomized controlled trials in the clinical evidence review. In universal decolonization, compared with placebo or no intervention, nasal mupirocin alone may result in little to no difference in the incidence of overall and S. aureus-related surgical site infections in pre-surgical patients undergoing orthopaedic, cardiothoracic, general, oncologic, gynaecologic, neurologic, or abdominal digestive surgeries, regardless of S. aureus carrier status (GRADE: Moderate to Very low). Compared with placebo, nasal mupirocin alone may result in little to no difference in the incidence of overall and S. aureus-related surgical site infections in pre-surgical patients who are S. aureus carriers undergoing cardiothoracic, vascular, orthopaedic, gastrointestinal, general, oncologic, gynaecologic, or neurologic surgery (GRADE: Moderate to Very low). In targeted decolonization, compared with placebo, nasal mupirocin combined with chlorhexidine body wash lowers the incidence of S. aureus-related surgical site infection (risk ratio: 0.32 [95% confidence interval: 0.16-0.62]) in pre-surgical patients who are S. aureus carriers undergoing cardiothoracic, vascular, orthopaedic, gastrointestinal, or general surgery (GRADE: High). Compared with no intervention, nasal mupirocin combined with chlorhexidine body wash in pre-surgical patients who are not S. aureus carriers undergoing orthopaedic surgery may have little to no effect on overall surgical site infection, but the evidence is very uncertain (GRADE: Very low). Most included studies did not separate methicillin-susceptible and methicillin-resistant strains of S. aureus. No significant antimicrobial resistance was identified in the evidence reviewed; however, the existing literature was not adequately powered and did not have sufficient follow-up time to evaluate antimicrobial resistance.Our economic evaluation found that universal nasal decolonization using mupirocin combined with chlorhexidine body wash is less costly and more effective than both targeted and no nasal decolonization. Compared with no nasal decolonization treatment, universal and targeted nasal decolonization using mupirocin combined with chlorhexidine body wash would prevent 32 and 22 S. aureus-related surgical site infections, respectively, per 10,000 patients. Universal nasal decolonization would lead to cost savings, whereas targeted nasal decolonization would increase the overall cost for the health care system since patients must first be screened for S. aureus carrier status before receiving nasal decolonization with mupirocin. The annual budget impact of publicly funding universal nasal decolonization in Ontario over the next 5 years ranges from a savings of $2.98 million in year 1 to a savings of $15.09 million in year 5. The annual budget impact of publicly funding targeted nasal decolonization ranges from an additional cost of $0.08 million in year 1 to an additional cost of $0.39 million in year 5.Our interview and survey respondents felt strongly about the value of preventing surgical site infections, and most favoured a universal approach.

CONCLUSIONS

Based on the best evidence available, decolonization of S. aureus using nasal mupirocin combined with chlorhexidine body wash prior to cardiothoracic, vascular, orthopaedic, gastrointestinal, or general surgery lowers the incidence of surgical site infection caused by S. aureus in patients who are S. aureus carriers (including methicillin-susceptible and methicillin-resistant strains) (i.e., targeted decolonization). However, nasal mupirocin alone may result in little to no difference in overall surgical site infections and S. aureus-related surgical site infections in pre-surgical patients prior to orthopaedic, cardiothoracic, general, oncologic, gynaecologic, neurologic, or abdominal digestive surgeries, regardless of their S. aureus carrier status (i.e., universal decolonization). No significant antimicrobial resistance was identified in the evidence reviewed.Compared with no nasal decolonization treatment, universal nasal decolonization with mupirocin combined with chlorhexidine body wash may reduce S. aureus-related surgical site infections and lead to cost savings. Targeted nasal decolonization with mupirocin combined with chlorhexidine body wash may also reduce S. aureus-related surgical site infections but increase the overall cost of treatment for the health care system. We estimate that publicly funding universal nasal decolonization using mupirocin combined with chlorhexidine body wash would result in a total cost savings of $45.08 million over the next 5 years, whereas publicly funding targeted nasal decolonization using mupirocin combined with chlorhexidine body wash would incur an additional cost of $1.17 million over the next 5 years.People undergoing surgery value treatments aimed at preventing surgical site infections.

Ceftriaxone Versus Cefazolin for the Treatment of Methicillin-Susceptible Staphylococcus aureus Bacteremia

BACKGROUND

Few studies have evaluated the use of ceftriaxone (CRO) in the treatment of methicillin-sensitive Staphylococcus aureus (MSSA) infections. The purpose of this study was to compare the safety and efficacy of CRO versus cefazolin (CFZ) for patients with MSSA bacteremia.

METHODS

This was a multi-center, single health-system retrospective study. Adult inpatients were included if they had a primary episode of MSSA bacteremia and received CRO or CFZ as definitive therapy. The primary endpoint was clinical cure at 7, 10, 14, and 28 days, or discharge, whichever came first. Secondary endpoints included treatment failure at 90 days, time to treatment failure, readmission due to recurrent MSSA bacteremia, duration of bacteremia, discontinuation of treatment due to adverse drug events, and Clostridioides difficile infection.

RESULTS

A total of 248 patients were included, of which 87 (35.1%) received CRO and 161 (64.9%) received CFZ. There was no difference in the primary outcome between the CRO group and the CFZ group (75 (86.2%) vs 145 (90.1%); p = 0.359), even after adjusting for Charlson Comorbidity Index and Pitt bacteremia score (aOR=1.35, 95% CI 0.58 -3.12; p = 0.49). There were no differences in time to clinical cure, treatment failure at 90 days, or safety events between the two groups.

CONCLUSION

Our findings suggest no clinical difference between CRO and CFZ for the definitive treatment of MSSA bacteremia. Further prospective studies are needed to confirm these findings.

The relationship between antibiotic agent and mortality in patients with febrile neutropenia due to Staphylococcal bloodstream infection: a multicenter cohort study

Background

Methicillin-susceptible Staphylococcus aureus (MSSA) is a common cause of bloodstream infection (BSI) in patients with febrile neutropenia, but treatment practices vary, and guidelines are not clear on the optimal regimen.

Methods

We conducted a multicenter retrospective cohort study of MSSA BSI in febrile neutropenia. We divided patients into 3 treatment groups: (1) broad-spectrum beta-lactams (ie, piperacillin-tazobactam, cefepime, meropenem); (2) narrow-spectrum beta-lactams (ie, cefazolin, oxacillin, nafcillin); and (3) combination beta-lactams (ie, both narrow- and broad-spectrum). We used multivariable logistic regression to compare 60-day mortality and bacteremia recurrence while adjusting for potential confounders.

Results

We identified 889 patients with MSSA BSI, 128 of whom had neutropenia at the time of the index culture: median age 56 (interquartile range, 43–65) years and 76 (59%) male. Of those, 56 (44%) received broad-spectrum beta-lactams, 30 (23%) received narrow-spectrum beta-lactams, and 42 (33%) received combination therapy. After adjusting for covariates, including disease severity, combination therapy was associated with a significantly higher odds for 60-day all-cause mortality compared with broad spectrum beta-lactams (adjusted odds ratio [aOR], 3.39; 95% confidence interval [CI], 1.29–8.89; P = .013) and compared with narrow spectrum beta-lactams, although the latter was not statistically significant (aOR, 3.30; 95% CI, .80–13.61; P = .071).

Conclusions

Use of combination beta-lactam therapy in patients with MSSA BSI and febrile neutropenia is associated with a higher mortality compared with treatment with broad-spectrum beta-lactam after adjusting for potential confounders. Patients in this study who transitioned to narrow-spectrum beta-lactam antibiotics did not have worse clinical outcomes compared with those who continued broad-spectrum beta-lactam therapy.

Pharmacokinetic Evaluation of Cefazolin in the Cerebrospinal Fluid of Critically Ill Patients

Background

The relative distribution of cefazolin into the cerebrospinal fluid (CSF) remains debated. Determining the distribution of cefazolin into the CSF in noninfected adults may allow for further treatment applications of cefazolin. This prospective pharmacokinetic study aimed to determine the pharmacokinetic parameters of cefazolin in serum and CSF from external ventricular drains (EVDs) in neurologically injured adults.

Methods

Blood and CSF were collected, using a biologic waste protocol, for cefazolin quantification and trapezoidal rule–based pharmacokinetic analysis in a total of 15 critically ill adults receiving 2000 mg intravenously every 8 hours or the renal dose equivalent for EVD prophylaxis.

Results

A median (range) of 3 (2–4) blood and 3 (2–5) CSF samples were collected for each patient. The most common admitting diagnosis was subarachnoid hemorrhage (66.7%). The median calculated cefazolin CSF C_max and C_min values (interquartile range [IQR]) were 2.97 (1.76–8.56) mg/L and 1.59 (0.77–2.17) mg/L, respectively. The median (IQR) CSF to serum area under the curve ratio was 6.7% (3.7%–10.6%), with time-matched estimates providing a similar estimate (8.4%). Of those receiving cefazolin every 8 hours, the median and minimum directly measured CSF cefazolin concentration ≥4 hours following administration were 1.87 and 0.78 mg/L, respectively.

Conclusions

Cefazolin dosed for EVD prophylaxis achieved CSF concentrations suggesting viability as a therapeutic option for patients with meningitis or ventriculitis due to susceptible bacteria such as methicillin-susceptible Staphylococcus aureus. Further clinical trials are required to confirm a role in therapy for cefazolin. Population-based pharmacokinetic–pharmacodynamic modeling may suggest an optimal cefazolin regimen for the treatment of central nervous system infections.

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.