A patient of Rheumatic heart disease developed infective endocarditis after dental extraction. Most likely organism causing this is:
**Core Concept**
Rheumatic heart disease often leads to valvular damage, which can predispose patients to infective endocarditis, a condition where bacteria infect the heart valves. The oral cavity is a common source of bacteria that can cause endocarditis, especially after procedures like dental extraction.
**Why the Correct Answer is Right**
The most likely organism causing infective endocarditis in this patient is **Streptococcus viridans**. This bacterium is commonly found in the oral cavity and can enter the bloodstream during dental procedures, leading to endocarditis. The viridans group of streptococci, including _Streptococcus mutans_ and _Streptococcus sanguinis_, are known to colonize the teeth and are often implicated in endocarditis cases.
**Why Each Wrong Option is Incorrect**
**Option A:** Not specified, but if it's a choice for a specific organism, it would likely be incorrect as there's no evidence to support it being the most likely cause in this scenario.
**Option B:** Other organisms like _Staphylococcus aureus_ or coagulase-negative staphylococci can also cause endocarditis, but they are less commonly associated with dental procedures and more often seen in cases of nosocomial or community-acquired infections.
**Option C:** _Escherichia coli_ is a gram-negative rod that can cause endocarditis, but it is less likely to be the primary cause in this scenario, as it is more commonly associated with urinary tract infections or other sources of bacteremia.
**Clinical Pearl / High-Yield Fact**
When managing patients with rheumatic heart disease, it's essential to consider the risk of infective endocarditis, especially after dental procedures. A thorough dental evaluation and prophylactic antibiotics may be necessary to prevent this complication.
**Correct Answer:** C. _Escherichia coli_