Which beta-lactamase genotype is currently the most prevalent extended-spectrum beta-lactamase (ESBL) family both worldwide and among Indian clinical isolates of Escherichia coli and Klebsiella pneumoniae?
- A TEM type
- B CTX-M type ✓
- C SHV type
- D PER type
Correct answer: B. CTX-M type
Explanation
CTX-M enzymes have displaced TEM and SHV as the dominant ESBLs globally and in India, with CTX-M-15 being the single most widespread variant. Their name reflects preferential hydrolysis of cefotaxime over ceftazidime, although CTX-M-15 also hydrolyses ceftazidime well. TEM and SHV were the classical ESBL families described first and remain common in some regions, but they no longer predominate anywhere, which eliminates them despite their historical importance.
Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.