From the Guidelines
Yes, Group C streptococci can cause endocarditis, though it's less common than endocarditis caused by other streptococcal groups. Group C streptococci are part of the normal flora in animals and can occasionally infect humans, particularly through contact with animals or consumption of unpasteurized dairy products. When these bacteria enter the bloodstream, they can attach to heart valves, especially damaged or prosthetic valves, leading to infective endocarditis.
Key Considerations
- The treatment of endocarditis caused by Group C streptococci typically involves high-dose intravenous penicillin G or ceftriaxone for 4-6 weeks, often combined with gentamicin for the first 2 weeks in severe cases, as suggested by 1.
- Patients with penicillin allergies may receive vancomycin, highlighting the importance of considering antibiotic susceptibility and potential allergies in treatment planning, as noted in 1 and 1.
- Early diagnosis and appropriate antibiotic therapy are crucial for successful treatment, as Group C streptococcal endocarditis can lead to serious complications including heart failure, embolic events, and valve destruction if left untreated.
Treatment Approach
- The choice of empirical therapy should consider epidemiological features and the clinical course of infection, with consultation from an infectious diseases specialist recommended for defining the most appropriate choice of therapy, as outlined in 1.
- For patients with culture-negative endocarditis, selection of an empirical treatment regimen should include consideration of the reason for negative blood cultures and the clinical presentation, with coverage for common bacterial causes of endocarditis, including S aureus, viridans group streptococci, and enterococci, as discussed in 1.
From the Research
Group C Strep and Endocarditis
- Group C strep is a rare cause of endocarditis, but it has a high potential for attachment to and destruction of normal heart valves 2.
- Major emboli to vital organs are frequently observed, and the mortality rate has been high 2.
- Synergistic combinations of penicillin and an aminoglycoside appear to result in lower morbidity compared to penicillin used alone 2.
- Early valve replacement may reduce the mortality in this extremely serious infection 2.
Case Reports and Studies
- A case report described a patient with endocarditis caused by group C streptococcus, which resulted in sequelae, right-eye endophthalmitis, and multilobar pneumonia caused by septic embolization from the infected mitral valve 3.
- Another study reported two cases of highly penicillin-resistant viridans group streptococcal endocarditis, which were treated with vancomycin-based regimens 4.
- The study found that vancomycin-based therapy was effective in curing the patients, and that gentamicin plus either β-lactams or vancomycin was more active than their respective monotherapies 4.
Treatment Options
- Penicillin-sensitive viridans or nonenterococcal group D streptococcal endocarditis may be treated successfully with aqueous penicillin G alone for four weeks or with combined penicillin and streptomycin for two weeks 5.
- Enterococcal endocarditis should be treated for four to six weeks with a combination of aqueous penicillin G together with either streptomycin or gentamicin 5.
- Ceftriaxone once daily for four weeks compared with ceftriaxone plus gentamicin once daily for two weeks is effective for the treatment of endocarditis due to penicillin-susceptible streptococci 6.