Is ceftriaxone less effective than other drugs for treating MSSA bloodstream infections?

For MSSA bloodstream infections (MSSA means methicillin-susceptible Staphylococcus aureus, a common staph germ that standard penicillins can still kill), doctors usually reach for antistaphylococcal penicillins or cefazolin. Ceftriaxone has become a popular alternative because it can be given once a day and tends to be safer on the kidneys. The catch is whether it actually works as well. A 2026 meta-analysis of 11 studies covering 2,568 patients found ceftriaxone was tied to higher 30-day death rates than the standard drugs ⁷. That said, the picture is not one-sided: 90-day mortality and clinical success did not differ significantly between the groups ⁷.

What the research says

The strongest evidence on this exact question comes from a meta-analysis pooling 11 studies of patients with MSSA bloodstream infections, comparing ceftriaxone against antistaphylococcal penicillins or cefazolin ⁷. Ceftriaxone was associated with significantly higher 30-day all-cause mortality (odds ratio 3.33; 95% CI 2.17-5.10) ⁷. That is a large gap, and it is the main reason some clinicians hesitate to use ceftriaxone as first-line therapy for this infection.

Other outcomes were less clear-cut. The same analysis found no significant difference at 90 days (odds ratio 1.71; 95% CI 0.75-3.90), and no significant differences in clinical success or microbiological clearance ⁷. Adverse event rates were also compared, though the abstract does not give a clear direction on that point ⁷. So the signal is strongest for early mortality, not for every measure of how patients do.

It helps to know why ceftriaxone gets used at all. It offers once-daily dosing and a favourable safety profile, which is exactly why it emerged as an alternative in the first place ⁷. Those practical advantages are real, but they have to be weighed against the mortality signal.

One important limit: the other sources provided do not address MSSA bloodstream infections. They cover ceftriaxone for pediatric pneumonia ¹, syphilis ², gonorrhoea ³, Brucella joint infections ⁶, and unrelated topics like Salmonella prevalence ⁴, HIV-related sepsis ⁵, and diagnostic sequencing ⁸. None of these can confirm or refute the MSSA findings, so the answer rests on the single meta-analysis ⁷.

What to ask your doctor

• Given the finding of higher 30-day mortality with ceftriaxone in MSSA bloodstream infections, is ceftriaxone still an appropriate choice for my case, or would a penicillin-type drug or cefazolin be preferred?
• What are the trade-offs for me personally, such as once-daily dosing convenience versus the mortality signal seen in the pooled studies?
• How will you monitor my response to treatment, and what would make you switch antibiotics?
• Are there factors in my situation (allergies, kidney function, other medicines) that change which drug is safest for me?