A 60-year-old male, a known case of COPD with hea failure was admitted with the complaints of shoness of breath and symptoms of right sided hea failure. He was catheterized and staed on treatment. After 8 days, he complained of pain in the right flank region, along with high grade fever with rigor. On examination it was observed that the urine in the catheter was cloudy and patient was also having pain in the urethral region. Urine R/M and culture studies were immediately sent. USG abdomen revealed pyelonephritis of the right kidney. Urine studies revealed increased WBCs in the urine sample. The organism was isolated, Gram staining was done. It showed tiny deep pink colonies on MacConkey agar. Colonies produced on tellurite agar are given below. The organism was heat resistant and could grow in 40% bile, 6.5% NaCl and at pH of 9.6. To which of the following drugs is the organism intrinsically resistant to: –
A 60-year-old male, a known case of COPD with hea failure was admitted with the complaints of shoness of breath and symptoms of right sided hea failure. He was catheterized and staed on treatment. After 8 days, he complained of pain in the right flank region, along with high grade fever with rigor. On examination it was observed that the urine in the catheter was cloudy and patient was also having pain in the urethral region. Urine R/M and culture studies were immediately sent. USG abdomen revealed pyelonephritis of the right kidney. Urine studies revealed increased WBCs in the urine sample. The organism was isolated, Gram staining was done. It showed tiny deep pink colonies on MacConkey agar. Colonies produced on tellurite agar are given below. The organism was heat resistant and could grow in 40% bile, 6.5% NaCl and at pH of 9.6. To which of the following drugs is the organism intrinsically resistant to: –
💡 Explanation
## **Core Concept**
The question describes a patient with a urinary tract infection (UTI) and provides clues about the causative organism based on its growth characteristics and resistance patterns. The organism in question exhibits specific growth patterns on various media, including MacConkey agar and tellurite agar, and shows resistance to certain environmental stresses.
## **Why the Correct Answer is Right**
The organism is described as producing tiny deep pink colonies on MacConkey agar, which suggests it is a gram-negative rod that can ferment lactose. The ability to grow on tellurite agar, and the characteristics of heat resistance, growth in 40% bile, 6.5% NaCl, and at a pH of 9.6, point towards an organism with a high degree of resistance to environmental stresses. These features are classic for *Enterococcus* species, which are known for their ability to grow in high salt concentrations and at high temperatures. *Enterococci* are intrinsically resistant to certain antibiotics due to their cell wall structure and efflux pumps.
## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is not provided, but typically, incorrect options would involve antibiotics to which *Enterococci* are usually susceptible or not intrinsically resistant.
- **Option B:** Similarly, without the specific drug listed, it's hard to directly refute, but if *Enterococci* are known to have intrinsic resistance to certain drugs, options that do not align with this knowledge would be incorrect.
- **Option D:** Again, lacking the specific drug, the reasoning would involve understanding which drugs *Enterococci* are generally susceptible to.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that *Enterococci*, particularly *E. faecium* and *E. faecalis*, exhibit intrinsic resistance to certain antibiotics, notably **low-level resistance to beta-lactams** (like penicillin and ampicillin) and **resistance to cephalosporins**. High-level resistance to certain drugs like vancomycin (Vancomycin-Resistant Enterococci, VRE) is a significant concern but is not intrinsic in all *Enterococci*.
## **Correct Answer:** D. Vancomycin
✓ Correct Answer: A. Cephalosporins
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