The Question is from neet-botany , and it was created by the author B VENKAT

Question

A patient presents with fever, chills, and a new heart murmur. Blood cultures are positive for Streptococcus viridans.  Which of the following is the MOST appropriate initial empiric antibiotic therapy?

B VENKAT · Accepted Answer

## CORE INFORMATION
✓ **Answer**: 2 (IV ceftriaxone + vancomycin)
## CONCEPT FRAMEWORK
 **Primary Concept**: Empiric antibiotic therapy for infective endocarditis
 **Related Topics**: Streptococcus viridans, infective endocarditis, antibiotic resistance, pharmacokinetics
 **Prerequisites**: Understanding of common pathogens causing infective endocarditis, antibiotic mechanisms of action, and treatment guidelines.
## SOLUTION PATHWAY
**Given Information**:
  * Patient presents with fever, chills, and a new heart murmur (suggestive of infective endocarditis).
  * Blood cultures positive for *Streptococcus viridans*.
  * Need to select the MOST appropriate INITIAL empiric antibiotic therapy.
**Method & Steps**:
 1. Identify the likely pathogen: *Streptococcus viridans* is a common cause of infective endocarditis, particularly in patients with predisposing factors (e.g., pre-existing valvular disease).
  Reasoning: The clinical presentation strongly suggests infective endocarditis.
  Formula/Rule: None directly applicable, but understanding of disease pathogenesis and common causative organisms is crucial.
 2. Consider potential antibiotic resistance: *Streptococcus viridans* can be resistant to penicillin and other beta-lactam antibiotics. Therefore, broader coverage is often necessary.
  Working:  While penicillin is effective against many strains, the risk of resistance necessitates a more robust initial approach.
  Key Point: Empiric therapy aims to cover the most likely pathogens while awaiting culture and sensitivity results.
 3. Select the appropriate initial empiric regimen: IV ceftriaxone + vancomycin provides broad-spectrum coverage, including potential resistance to penicillin. Ceftriaxone covers most *Streptococcus viridans* strains, and vancomycin addresses the possibility of resistant organisms or those producing beta-lactamases.
  Result: IV ceftriaxone + vancomycin is the most appropriate initial empiric therapy.
  Verification: This regimen aligns with current guidelines for the management of infective endocarditis.
 ## OPTION ANALYSIS
A :x: Oral amoxicillin:  Amoxicillin is often used for less severe streptococcal infections, but it is generally inadequate for treating infective endocarditis due to the risk of resistance and the need for high drug concentrations at the site of infection.  Oral administration also limits the drug's ability to reach therapeutic levels in the bloodstream.
B ✓: IV ceftriaxone + vancomycin: This combination provides broad-spectrum coverage for *Streptococcus viridans*, including strains resistant to penicillin.  IV administration ensures adequate drug levels.
C :x: IV gentamicin + vancomycin: Gentamicin is an aminoglycoside and is often used in combination with other antibiotics for endocarditis, but usually not as the primary agent with vancomycin. Ceftriaxone offers better gram-positive coverage than gentamicin.
D :x: Oral ciprofloxacin: Ciprofloxacin is a fluoroquinolone with poor activity against *Streptococcus viridans*. It is not appropriate for treating endocarditis.
 ## LEARNING AIDS
 **Common Mistakes**:
  1.Choosing solely amoxicillin based on prior knowledge of streptococcal sensitivity:  This ignores the possibility of resistance and the severity of endocarditis.
  2.Overlooking the need for IV administration: Oral antibiotics may not achieve sufficient concentrations to treat a serious infection like endocarditis.
 **Quick Tips**:
  1.Remember the classic presentation of infective endocarditis (fever, chills, new murmur).
  2.Empiric therapy for endocarditis should aim for broad-spectrum coverage due to the potential for antibiotic resistance.

B VENKAT · Answer

Oral amoxicillin

B VENKAT · Answer

The correct Option is "IV ceftriaxone + vancomycin"

B VENKAT · Answer

IV gentamicin + vancomycin

B VENKAT · Answer

Oral ciprofloxacin

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