Pharmacodynamics of ceftriaxone for the treatment of methicillin-susceptible Staphylococcus aureus: Is it a viable treatment option?

Significant Publications on Infectious Diseases Pharmacotherapy in 2022

Purpose: To provide summarization of the most significant infectious diseases (ID) pharmacotherapy articles published in peer-reviewed literature in 2022. Summary: Members of the Houston Infectious Diseases Network (HIDN) nominated notable articles providing significant contributions to ID pharmacotherapy in 2022. Article nominations included those pertaining to general ID, as well as those including coronavirus disease 2019 (COVID-19), and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) pharmacotherapy. A total of 71 articles were nominated by HIDN. Members: 68 articles pertaining to general ID pharmacotherapy and 3 articles focusing on HIV/AIDS. To aid selection of the most these most notable articles of 2022, a survey was created and distributed to members of the Society of Infectious Diseases Pharmacists (SIDP). Of the 153 SIDP members who participated in the survey, there were 128 recorded votes for the top 10 general ID pharmacotherapy articles and 30 votes recorded for the top HIV/AIDS article. The most notable publications are summarized. Conclusion: Post pandemic significant advances in antimicrobial stewardship and infectious disease states continues to occur in a world recently focused on the coronavirus disease 2019 (COVID-19) global pandemic. Continuous growth in publication of ID-related articles over the past year lends towards the aims of this review to aid clinicians in remaining current on key practice-changing ID pharmacotherapy publications from 2022.

Evaluating the antimicrobial efficacy of ceftriaxone regimens: 1 g twice daily versus 2 g once daily in a murine model of Streptococcus pneumoniae pneumonia

Background

Ceftriaxone is administered in regimens of either 2 g once-daily or 1 g twice-daily for the treatment of pneumonia caused by Streptococcus pneumoniae. Previous clinical study suggests the 2 g once-daily regimen is more effective, but comparison of antimicrobial efficacy between are lacking.

Objectives

To assess the antimicrobial efficacy of these two ceftriaxone regimens against S. pneumoniae using a murine model of pneumonia.

Methods

The study employed three S. pneumoniae isolates with ceftriaxone MICs of 1, 2 and 4 mg/L and two human-simulated regimens based on the blood concentration of ceftriaxone (1 g twice-daily and 2 g once-daily). Antimicrobial activity was quantified based on the change in bacterial counts (Δlog10 cfu/lungs) observed in treated mice after 24 h, relative to the control mice at 0 h.

Results

The human-simulated 2 g once-daily regimen of ceftriaxone exhibited significantly higher antimicrobial activity against S. pneumoniae isolates with MICs of 1 and 2 mg/L compared with the 1 g twice-daily regimen (1 mg/L, -5.14 ± 0.19 Δlog10 cfu/lungs versus -3.47 ± 0.17 Δlog10 cfu/lungs, P < 0.001; 2 mg/L, -3.41 ± 0.31 Δ log10 cfu/lungs versus -2.71 ± 0.37 Δlog10 cfu/lungs, P = 0.027). No significant difference in antimicrobial activity was observed against the S. pneumoniae isolate with a MIC of 4 mg/L between the two regimens (-0.33 ± 0.18 Δlog10 cfu/lungs versus -0.42 ± 0.37 Δlog10 cfu/lungs, P = 0.684).

Conclusion

2 g once-daily regimen of ceftriaxone is more effective for treating pneumonia caused by S. pneumoniae, with MICs of ≤2 mg/L.

Outcomes of Ceftriaxone Compared With Cefazolin or Nafcillin/Oxacillin for Outpatient Therapy for Methicillin-Sensitive Staphylococcus aureus Bloodstream Infections: Results From a Large United States Claims Database

Background

Ceftriaxone is a convenient option for methicillin-sensitive Staphylococcus aureus (MSSA) outpatient parenteral antimicrobial therapy (OPAT), but population-based studies for its effectiveness are lacking.

Methods

In this retrospective cohort, a large insurance claims database was queried from 2010 to 2018 for adults with MSSA bloodstream infection (BSI). Patients discharged on OPAT on cefazolin or oxacillin/nafcillin were compared with ceftriaxone with respect to 90-day hospital readmission with the same infection category and 90-day all-cause readmission using logistic regression models.

Results

Of 1895 patients with MSSA BSI, 1435 (75.7%) patients received cefazolin, oxacillin, or nafcillin and 460 (24.3%) ceftriaxone. Readmission due to the same infection category occurred in 366 (19.3%), and all-cause readmission occurred in 535 (28.3%) within 90 days. Risk factors significantly associated with readmission with the same infection category were the oldest sampled age group (61-64 years: adjusted odds ratio [aOR], 1.47 [95% confidence interval {CI}, 1.01-2.14]), intensive care unit stay during index admission (aOR, 2.33 [95% CI, 1.81-3.01]), prosthetic joint infection (aOR, 1.96 [95% CI, 1.18-2.23]), central line-associated BSI (aOR, 1.72 [95% CI, 1.33-2.94]), and endocarditis (aOR, 1.63 [95% CI, 1.18-2.23]). Ceftriaxone was not associated with increased risk of readmission with the same infection category (aOR, 0.89 [95% CI, .67-1.18]), or 90-day all-cause readmission (aOR, 0.86 [95% CI, .66-1.10]) when compared with oxacillin/nafcillin/cefazolin.

Conclusions

In this cohort of MSSA BSI patients discharged on OPAT, there were no differences in outcomes of readmission with the same infection and 90-day all-cause readmission in patients treated with ceftriaxone compared to oxacillin/nafcillin or cefazolin. Patients with complicated BSIs such as endocarditis and epidural abscess were more likely to be prescribed cefazolin or oxacillin/nafcillin.

Associated Outcomes of Different Intravenous Antibiotics Combined with 2% Mupirocin Ointment in the Treatment of Pediatric Patients with Staphylococcal Scalded Skin Syndrome

Purpose

To compare treatment duration, influencing factors, and costs among intravenous antibiotic groups combined with 2% mupirocin ointment for treating staphylococcal scalded skin syndrome (SSSS).

Patients and Methods

Sex, age, onset days before admission, febrile status, white blood cell (WBC) count, and C-reactive protein (CRP) level were recorded as baseline characteristics for 253 included patients. The antibiotic sensitivity results were statistically compared by Cochran's Q test. Kruskal-Wallis tests were used to compare days and the total costs of hospitalization with different intravenous antibiotic applications. Mann-Whitney U-tests or Spearman's rank correlation tests were used for the univariate analysis. Finally, a multivariate linear regression model was employed to determine the variables with statistical significance.

Results

The sensitivity rates of oxacillin (84.62%), vancomycin (100%), and mupirocin (100%) were significantly higher than those of clindamycin (7.69%) (p<0.0001). The duration of intravenous ceftriaxone administration was significantly longer than that of amoxicillin-clavulanic acid, cefathiamidine, and cefuroxime (p<0.01). The total hospitalization costs for cefathiamidine were significantly higher than those for amoxicillin-clavulanic acid and cefuroxime (p<0.05). According to the multiple linear regression, ages ≥60 months old were correlated with shorter treatment duration (β=-1.48, [95% CI: -2.29, -0.66] for amoxicillin-clavulanic acid, and β=-1.44, [95% CI: -2.06, -0.83] for cefathiamidine, and β=-0.96, [95% CI: -1.58, -0.34] for cefuroxime) (all p<0.01). In multivariate analysis for cefathiamidine, higher WBC count (β=0.05, [95% CI: 0.01, 0.10], p<0.05) and CRP level (β=1.12, [95% CI: 0.14, 2.10], p<0.05) were associated with longer treatment course.

Conclusion

Oxacillin resistance was rare, and clindamycin resistance was high in pediatric patients with SSSS in our district. Intravenous amoxicillin-clavulanic acid and cefuroxime combined with topical mupirocin were favorable due to a shorter intravenous treatment course and lower costs. Younger age, elevated WBC count, and CRP levels could indicate a longer course of treatment with intravenous antibiotics.

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.

Post-treatment outcomes of ceftriaxone versus antistaphylococcal penicillins or cefazolin for definitive therapy of methicillin-susceptible Staphylococcus aureus bacteremia

Methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia is associated with poor outcomes. Ceftriaxone offers logistical advantages over other standard therapies, though in vitro studies have questioned its efficacy and clinical studies of ceftriaxone in MSSA bacteremia are conflicting.We performed a multicenter, retrospective cohort study of adult patients who received ceftriaxone, cefazolin, or antistaphylococcal penicillins as definitive therapy for MSSA bacteremia from 2018 to 2019. Definitive therapy was defined as the antibiotic used in the outpatient setting. Patients were excluded if they received less than 7 days of outpatient therapy. Follow-up started on the date of definitive therapy completion. The primary outcome was 90-day treatment failure, defined as a composite of mortality and microbiologic recurrence. This was analyzed with multivariable Cox regression. A total of 223 patients were included, 37 (16.6%) of whom received ceftriaxone. The most common ceftriaxone dose was 2 g daily (83.8%). The most common primary site of infection was skin/soft tissue (37.2%), unknown (21.1%), and catheter-related (15.2%). Twenty-six (11.7%) developed infective endocarditis. Median total duration of treatment was 31.0 days, and median outpatient duration was 24.0 days. Twenty-six (11.7%) developed 90-day treatment failure. After adjusting for Charlson comorbidity index, duration of therapy, and use of transesophageal echocardiography, definitive treatment with ceftriaxone was associated with treatment failure (hazard ratio 2.66, 95% confidence interval 1.15-6.12; p=0.022). Among patients with MSSA bacteremia, definitive treatment with ceftriaxone was associated with a higher risk of treatment failure within 90 days as compared to cefazolin or antistaphylococcal penicillins.

Update on Staphylococcus aureus bacteraemia

PURPOSE OF REVIEW

To review recently published evidence relevant to Staphylococcus aureus bacteremia (SAB).

RECENT FINDINGS

Staphylococcus aureus is the most common pathogen causing co-infections and superinfections in patients with COVID-19. Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia ratios have sharply risen during the pandemic. SAB mortality is 18% at 1 month and 27% at 3 months but has gradually decreased over the last 30 years. Recurrences and reinfections are common (9%). Standardised items to define complicated SAB, and a new cut-off defining persisting bacteremia after 2 days with positive blood cultures have been proposed. Multiple antibiotic combinations have been trialled including vancomycin or daptomycin with β-lactams, fosfomycin, or clindamycin, without significant results. In the recently published guidelines, vancomycin remains the first line of treatment for MRSA bacteremia. For the management of methicillin-susceptible Staphylococcus aureus , cefazolin less frequently causes acute kidney injury than flucloxacillin, and when susceptibility is demonstrated, de-escalation to penicillin G is suggested.

SUMMARY

Our review confirms that Staphylococcus aureus represents a special aetiology among all causes of bloodstream infections. Pending results of platform and larger trials, its distinct epidemiology and determinants mandate careful integration of clinical variables and best available evidence to optimize patient outcomes.

Retrospective Comparison of the Effectiveness and Safety of Ceftriaxone 1 g Twice Daily versus 2 g Once Daily for Treatment of Aspiration Pneumonia

Although a 2 g once daily administration of ceftriaxone remains the standard dosing regimen for the treatment of aspiration pneumonia, there are no studies to investigate the optimal dosing method. Hence, we retrospectively evaluated the effectiveness and safety of 1 g twice daily versus 2 g once daily administration of ceftriaxone in adult patients with aspiration pneumonia. Patients who received ceftriaxone for the treatment of aspiration pneumonia between 2015 and 2021 were included in this study. Clinical responses, inflammatory markers, and incidence of adverse events after completion of ceftriaxone therapy were investigated. In total, 33 patients received 1 g twice daily (group 1) and 28 received 2 g once daily (group 2) ceftriaxone for the treatment of mild-to-moderate aspiration pneumonia. Compared with that of group 1, group 2 demonstrated significantly improved clinical responses (group 1 vs. group 2, 84.8% vs. 100%, p = 0.0316). Although the safety profile was not significantly different between the two groups, the incidence of choleliths during ceftriaxone therapy in group 1 was higher than that in group 2 (31.3% vs. 9.1%, p = 0.174). Therefore, a 2 g once daily administration of ceftriaxone appeared to be a simple regimen adequate for the treatment of inpatients with mild-to-moderate aspiration pneumonia, which might not be heavily involved by anaerobes.

Effectiveness and Safety of Ceftriaxone Compared to Standard of Care for Treatment of Bloodstream Infections Due to Methicillin-Susceptible Staphylococcus aureus: A Systematic Review and Meta-Analysis

(1) Background: Ceftriaxone is a potential alternative for the treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections (BSIs) in acute care and outpatient parenteral antimicrobial therapy (OPAT) settings. We evaluated the effectiveness and safety of ceftriaxone for the treatment of MSSA BSIs. (2) Method: We searched PubMed, Embase, and Cochrane Library from their inception to October 30th 2021. Our outcomes included clinical cure, microbiological cure, 30- and 90-day mortality, 90-day hospital readmission, and adverse drug reactions (ADRs). We compared ceftriaxone against standard of care (SOC) therapy. We used the random-effects model for the meta-analysis, and our estimated effects were reported as odds ratios (ORs) with 95% confidence intervals (CI). (3) Results: Twelve retrospective cohort studies were included, comprising 1037 patients in the ceftriaxone arms and 2088 patients in the SOC arms. The clinical cure rate of the ceftriaxone regimen was not statistically different from SOC: OR 0.65 (95% CI: 0.29-1.45). Ceftriaxone was also not statistically different from SOC in microbiological cure: OR 1.48 (95% CI: 0.29-7.51); 30-day mortality: OR 0.79 (95% CI: 0.14-4.65); 90-day mortality: OR 0.82 (95% CI: 0.38-1.80); 90-day hospital readmission: OR 1.20 (95% CI: 0.92-1.56); and ADRs: OR 0.92 (95% CI: 0.39-2.18). (4) Conclusion: Ceftriaxone could provide an alternative for the treatment of MSSA BSIs in acute care and OPAT settings (except in patients whose BSIs were due to infective endocarditis).