Cefazolin therapy for methicillin-susceptible Staphylococcus aureus bacteremia in Japan

Comparative Effectiveness of Ampicillin/Sulbactam versus Cefazolin as Targeted Therapy for Bacteremia Caused by Beta-Lactamase-Producing Methicillin-Sensitive Staphylococcus aureus: A Single-Center Retrospective Study

Cefazolin (CFZ) is the first-line treatment for beta-lactamase-producing methicillin-sensitive Staphylococcus aureus (BP-MSSA) infection. In 2019, Japan experienced a CFZ shortage because of foreign object inclusion in a batch. Ampicillin/sulbactam (SAM) was preferred in many cases as definitive therapy for the treatment of BP-MSSA bacteremia to preserve broad-spectrum antibiotic stock. However, there are no previous studies reporting the clinical efficacy of SAM for BP-MSSA bacteremia. We aimed to compare the clinical efficacy and adverse effects of SAM versus CFZ in patients with BP-MSSA bacteremia. In total, 41 and 30 patients treated with SAM and CFZ, respectively, were identified. The baseline characteristics were similar in both groups. No significant differences were observed in length of hospital stay and all 30-day mortality between the two groups (p = 0.270 and 0.643, respectively). Moreover, no intergroup difference in 90-day mortality was found (hazard ratio 1.02, 95% confidential interval 0.227-4.53). Adverse effects, such as liver dysfunction, were less in the CFZ group than in the SAM group (p = 0.030). Therefore, in cases of poor CFZ supply or in patients allergic to CFZ and penicillinase-stable penicillins, SAM can be an effective therapeutic option for bacteremia due to BP-MSSA with attention of adverse effects, such as liver dysfunction.

Effects of the cefazolin shortage on the sales, cost, and appropriate use of other antimicrobials

Background

Shortages of antimicrobials lead to treatment failures, increase medical costs, and accelerate the development of antimicrobial resistance. We evaluated the effects of the serious cefazolin shortage in 2019 in Japan on the sales, costs, and appropriate use of other antimicrobials.

Methods

We evaluated monthly defined daily doses/1000 inhabitants/day (DID) values of antimicrobial sales from January 2016 to December 2019 using wholesaler’s sales databases. Using 2016–2018 sales data, we generated a prediction model of DID in 2019 under the assumption that the cefazolin shortage did not occur. We then compared the predicted DID and actual DID. Cefazolin, government-recommended alternatives, and government-not-recommended broad-spectrum alternatives were assessed. Antimicrobial groups according to the AWaRe classification were also assessed to evaluate the effect on appropriate antimicrobial use. In addition, we evaluated changes in costs between 9 months before and after the cefazolin shortage.

Results

DID values of total antimicrobials increased sharply 1 month before the decrease in cefazolin. Actual DIDs were higher than predicted DIDs for ceftriaxone, flomoxef, clindamycin, cefotiam, piperacillin/tazobactam, and meropenem. Actual DID values were higher than the predicted DID values in the Watch group. The costs of antimicrobials between pre- and post- cefazolin shortage were unchanged.

Conclusion

The cefazolin shortage brought confusion to the antimicrobial market and led to a setback in the appropriate use of antimicrobials. Early recognition and structures for prompt reactions to antimicrobial shortages are needed. Moreover, development of a system to secure the supply of essential antimicrobials is required.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-07139-z.

A comparison of safety and outcomes with cefazolin versus nafcillin for methicillin-susceptible Staphylococcus aureus bloodstream infections

BACKGROUND

Methicillin-susceptible Staphylococcus aureus (MSSA) is a frequent cause of bloodstream infections (BSI). Treatment with nafcillin (NAF) has been preferred to cefazolin (CFZ). However, comparable outcomes have been found with CFZ with possibly lower risk for side-effects. This study compared safety and effectiveness of NAF versus CFZ for MSSA BSI.

METHODS

This single center retrospective study evaluated adults admitted with MSSA BSI who received NAF or CFZ. Patients receiving ≥24 h of antibiotics were included for safety analyses. Patients receiving NAF or CFZ for ≥75% of a 14 day minimum treatment course were assessed for clinical effectiveness. The primary safety outcome was incidence of renal toxicity with multiple secondary safety endpoints. Clinical success was defined as symptom resolution, repeat negative cultures, lack of additional therapy for presumed failure, and lack of recurrence within 30 days.

RESULTS

A total of 130 patients receiving NAF (n = 79) or CFZ (n = 51) were included for safety analysis. Of those, 90 met criteria for effectiveness assessment (NAF n = 40, CFZ n = 50). Baseline characteristics were well matched. NAF was associated with a higher incidence of nephrotoxicity compared to CFZ (25% vs. 2%, RR 1.31, 95% CI 1.15-1.5, p < 0.001), allergic reactions (p = 0.01) and a trend for hepatotoxicity (p = 0.08). Clinical success was achieved in 82% NAF and 94% CFZ treated patients (p = 0.1).

CONCLUSION

CFZ was associated with less nephrotoxicity and no difference in clinical success compared to NAF for MSSA BSI. A prospective study comparing NAF to CFZ for MSSA BSI should be conducted to elucidate differences in therapies.

Inoculum effect of high concentrations of methicillin-susceptible Staphylococcus aureus on the efficacy of cefazolin and other beta-lactams

The existence of a cefazolin inoculum effect (InE) of methicillin-susceptible Staphylococcus aureus (MSSA), which is speculated to be a reason for cefazolin treatment failure in MSSA infections, is controversial. In Japan, although cefazolin is one of the therapeutic choices for patients with MSSA infection, there are few reports of this effect. Additionally, the association between InE and blaZ type in beta-lactams other than cefazolin has not been well documented. In this study, we confirmed an MSSA InE in several beta-lactams, including cefazolin, and its relationship with blaZ, using 52 MSSA isolates from blood cultures. Three isolates (5.8%) that possessed type A blaZ showed a pronounced cefazolin InE. Five isolates (9.6%) showed pronounced InE with sulbactam/ampicillin; four isolates had type C blaZ and one had type A blaZ. However, we confirmed InE in MSSA isolates with blaZ not only type A and C but also B and D. For cefotaxime, ceftriaxone, imipenem, and meropenem, regardless of the presence of blaZ, we did not observe a significant increase in MICs at a high inoculum of MSSA. Hence, our results suggest that the above four beta-lactams are good alternatives to cefazolin if InE leads to treatment failure in a patient.

Adherence rate of quality-of-care indicators for Staphylococcus aureus bacteremia is extremely low in Japanese emergency and critical care departments: a multicenter retrospective observational study

Aim

Staphylococcus aureus bacteremia causes significant morbidity and mortality and requires specific management to prevent complications. Most studies evaluating quality of care have been carried out in Europe and North America, and accurate epidemiological data are lacking in Asia. We aimed to describe the epidemiology and evaluate the quality of care for S. aureus bacteremia in Japan.

Methods

From February 2011 to January 2014, we undertook a multicenter retrospective observational study in 10 departments of emergency and critical care in Japan. We included 118 hospitalized adult patients with S. aureus bacteremia and evaluated three quality‐of‐care indicators: follow‐up blood culture, treatment duration, and echocardiography.

Results

The mean age of the patients was 63.5 ± 17.0 years. The major source of bacteremia was pneumonia (n = 22, 19%), followed by skin and soft tissue infection (n = 18, 15%). Thirty patients (25%) died in the hospital. Follow‐up blood culture was performed in 21/112 patients (19%). The duration of antimicrobial treatment was sufficient in 49/87 patients (56%). Echocardiography for patients with clinical indication was undertaken in 39/59 patients (66%). Any of the three indicators were inadequate in 101/118 (86%).

Conclusion

The rate of adequate care for S. aureus bacteremia is low in Japan. The low adherence rate for follow‐up blood culture was particularly notable. Staphylococcus aureus bacteremia can be an important target of quality improvement interventions.