From the Guidelines
Zosyn (piperacillin-tazobactam) and vancomycin are effective against Streptococcus viridans, while azithromycin has limited activity and is not recommended as first-line therapy for serious infections. The choice of antibiotic should be guided by susceptibility testing when available, as resistance patterns can vary 1. For serious infections like endocarditis or bacteremia, combination therapy might be necessary, with vancomycin being a highly effective alternative for penicillin-resistant strains or in patients with penicillin allergies 1. Treatment duration depends on the infection site and severity, ranging from 7-14 days for uncomplicated infections to 4-6 weeks for endocarditis, with monitoring for clinical improvement and potential side effects being essential during treatment 1. Some key points to consider when treating Streptococcus viridans infections include:
- Penicillins like piperacillin (in Zosyn) are typically first-line agents for viridans streptococci infections
- Vancomycin is highly effective and often used for penicillin-resistant strains or in patients with penicillin allergies
- Azithromycin has limited activity against viridans streptococci and is generally not recommended as first-line therapy for serious viridans group infections
- Combination therapy might be necessary for serious infections like endocarditis or bacteremia
- Treatment duration and monitoring for clinical improvement and potential side effects are crucial during treatment 1.
From the FDA Drug Label
Vancomycin Hydrochloride for Injection, USP has been reported to be effective alone or in combination with an aminoglycoside for endocarditis caused by S. viridans or S. bovis. Azithromycin has been shown to be active against most isolates of the following bacteria, both in vitro and in clinical infections... Gram-positive bacteria ... Viridans group streptococci The FDA drug label does not provide sufficient information to determine the effectiveness of Zosyn against Strep viridans. However, Vancomycin is reported to be effective alone or in combination with an aminoglycoside for endocarditis caused by S. viridans 2. Azithromycin has been shown to be active against Viridans group streptococci 3.
From the Research
Antibiotic Effectiveness Against Strep Viridans
- Zosyn (a combination of piperacillin and tazobactam) is not mentioned in the provided studies as a treatment option for Strep viridans.
- Azithromycin is not mentioned in the provided studies as a treatment option for Strep viridans.
- Vancomycin is mentioned in several studies as a potential treatment option for Strep viridans, particularly for penicillin-resistant strains 4, 5.
Susceptibility Patterns
- The studies suggest that vancomycin is effective against Strep viridans, with all isolates found to be susceptible in one study 4.
- Penicillin susceptibility varies among different species of Strep viridans, with some species showing lower susceptibility rates 6, 7.
- Ceftriaxone is also effective against Strep viridans, with high susceptibility rates reported in several studies 8, 7.
Treatment Options
- The studies suggest that vancomycin-based regimens may be effective for treating penicillin-resistant Strep viridans infections 5.
- Ceftriaxone and penicillin G are also considered reasonable treatment options for complicated Strep viridans bacteremia, although comparisons between these agents are limited 8.