Current management of spinal epidural abscesses (SEAs) caused by methicillin-susceptible Staphylococcus aureus (MSSA) includes antistaphylococcal penicillins (ASPs) as first-line agents and cefazolin as an alternative, without a well-defined optimal duration of therapy.
Clinical hesitancy for cefazolin for SEAs with MSSA involves in vitro evidence of the inoculum effect due to β-lactamase hydrolysis, leading to increased treatment failures, as well as conflicting evidence surrounding cefazolin’s penetration into the central nervous system space. Currently, no data specifically compare ASPs and cefazolin in SEAs. However, current data do support the use of cefazolin for MSSA bloodstream infections (BSIs), further raising the question of using cefazolin as a first-line agent because many SEAs are often caused by hematogenous spread.1,2
A multicenter, retrospective cohort trial at Mayo Clinic sites included patients from 2004 to 2020 who had a MSSA SEA diagnosed through epidural fluid collection and either CT or MRI. Antibiotic regimens included cefazolin 2 grams intravenous (IV) every 8 hours, oxacillin 2 grams IV every 4 hours, or nafcillin 2 grams IV every 4 hours. Patients were in the cefazolin or ASP group based on which treatment they received for more than 50% of their total treatment duration, allowing for empiric coverage upon initial presentation to differ. The primary outcome was treatment failure (defined as extending therapy) at 6 weeks.
Seventy-nine patients were included: 45 patients received cefazolin, 29 received nafcillin, and 5 received oxacillin. See Table 1 for baseline characteristics and outcomes among groups. The majority of patients in both groups had multilevel epidural involvement. There was no difference in treatment failure at 6 weeks; most patients received treatment beyond 6 weeks (82.4% vs 75.6% in the ASP vs cefazolin groups, respectively; P=.58). Along with antimicrobial medical management, 92.4% of patients also underwent surgical management of SEA.
Additionally, no difference was detected between groups for other outcomes such as 30-day mortality (5.9% ASP vs 2% cefazolin) and 90-day recurrence (9.4% ASPs vs 11.4% cefazolin). Total duration of therapy was not statistically different in ASP vs cefazolin groups (median [interquartile range], 67.5 [45-93.7] days vs 55.5 [42.2-96] days; P=.44). However, patients with multilevel epidural involvement were treated with longer antibiotic courses compared to those with single-level involvement (85 [45-110] days vs 41 [41-60] days; P<.01).
This study, albeit small and retrospective, supports the use of cefazolin in SEAs compared to ASPs, with no detectable difference in treatment outcomes. Although similar rates of discontinuation due to adverse events were seen in this study, cefazolin is often chosen over ASPs for improved tolerability and safety or for patients with preexisting kidney or liver impairment. Cost is another consideration often favoring cefazolin when treating SEAs—given the prolonged duration.
The different dosing frequency of each antibiotic allows for selection of a treatment that will best fit each individual patient’s lifestyle. The study also highlighted the importance of surgical treatment of SEAs (>90% of patients underwent aspiration or surgical debridement). Finally, cefazolin can be considered an initial agent of choice in patients with concomitant BSI, infective endocarditis, and/or SEA, as data support its outcomes when compared to ASPs.
However, a patient’s risk factors, surgical management plan, and epidural involvement must be carefully considered to decide appropriate treatment duration, which is still undetermined for SEAs.
Corsini Campioli C, Go JR, Abu Saleh O, Challener D, Yetmar Z, Osmon DR. Antistaphylococcal penicillin versus cefazolin for the treatment of methicillin-susceptible Staphylococcus aureus spinal epidural abscesses. Open Forum Infect Dis. 2021;8(3):ofab071. doi:10.1093/ofid/ofab071