270 - Clinical Outcomes of Ceftriaxone versus Penicillin G for Complicated Viridans Group Streptococci Bacteremia

Background: Viridans group streptococci (VGS) is an infrequent yet significant cause of bloodstream infections, and complicated cases may require prolonged antibiotic therapy. Ceftriaxone (CTX) and penicillin G (PCN G) are both considered first line options for VGS infections, but comparisons between these agents are limited. We evaluated the clinical outcomes amongst patients treated with CTX and PCN G for complicated VGS bacteremia.

Methods: This was a single-center, retrospective study of adult patients with ≥1 positive VGS blood culture who were treated with either CTX or PCN G/ampicillin (both included in PCN G arm) between January 2013 and June 2019. The primary outcome was a composite of safety endpoints, including hospital readmission due to VGS or an adverse event (AE) from therapy, Clostridioides difficile infections, treatment modification or discontinuation due to an antibiotic-related AE, and development of extended-spectrum beta lactamase resistance. Secondary outcomes included the individual safety endpoints, VGS bacteremia recurrence, hospital readmission, and all-cause mortality.

Results: Of 328 patients screened for inclusion, 94 patients met eligibility criteria (CTX n= 64, PCN G n=34). Median age was 68 years (IQR 56-81) and 68% were male. Study patients did not present with critical illness, as reflected by a median Pitt bacteremia score of 0 in the CTX and 1 in the PCN G arms, P=0.764. Streptococcus mitis was the most common VGS isolate and infective endocarditis (IE) was the predominant source of infection. CTX was not significantly associated with increased risk of the primary outcome (14% vs. 27%; P= 0.139). The driver of the composite outcome was hospital readmission due to VGS bacteremia or therapy complications. Results were similar in the subgroup of patients with IE (12.5% vs. 23.5%). No secondary endpoints differed significantly between groups. On multivariate analysis, source removal was a protective factor of the primary outcome (OR 0.1; 95% CI 0.020-0.6771; P= 0.017).

Conclusion: Despite potential safety concerns with the prolonged use of CTX in complicated VGS bacteremia, this study did not demonstrate a higher rate of treatment failure, adverse events, or resistance. These findings warrant further exploration.