Which beta-lactamase family is currently the most widespread ESBL type worldwide, having displaced older enzymes in clinical isolates of Enterobacterales?
- A TEM
- B SHV
- C CTX-M ✓
- D PER
Correct answer: C. CTX-M
Explanation
CTX-M enzymes have become the dominant ESBL family globally, particularly CTX-M-15 in India, driven largely by the pandemic ST131 Escherichia coli clone. They preferentially hydrolyse cefotaxime over ceftazidime, hence the name cefotaximase. TEM and SHV were the first described ESBL lineages but now account for a minority of isolates. PER enzymes remain geographically restricted and uncommon.
Reference: Ananthanarayan and Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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