Question:
Regarding Extended-Spectrum Beta-Lactamase (ESBL)-producing organisms, which of the following statements are TRUE?
Regarding Extended-Spectrum Beta-Lactamase (ESBL)-producing organisms, which of the following statements are TRUE?
Show Hint
Which enzyme spreads on plasmids and is beaten only by carbapenems?
Updated On: Jun 25, 2026
- Carbapenems can be used for treatment
- Resistance is plasmid-transmitted
- Piperacillin-tazobactam is the reliable drug of choice
- Third-generation cephalosporins can be used
Show Solution
Verified By Collegedunia
The Correct Option is A
Solution and Explanation
Step 1: What ESBLs do.
Extended-spectrum beta-lactamases are enzymes that hydrolyse penicillins, oxyimino-cephalosporins (3rd-generation cephalosporins such as ceftriaxone, ceftazidime, cefotaxime) and aztreonam. They are inhibited by clavulanic acid in vitro but this does not translate into reliable clinical efficacy.
Step 2: Statement on carbapenems (TRUE).
Carbapenems (meropenem, imipenem, ertapenem) are the drugs of choice for serious ESBL infections — they are stable to ESBL hydrolysis.
Step 3: Statement on plasmid transmission (TRUE).
ESBL genes (e.g. CTX-M, TEM, SHV) are carried on plasmids, allowing horizontal spread and co-resistance to other antibiotic classes.
Step 4: Why piptaz and 3rd-gen cephalosporins are wrong.
By definition ESBLs hydrolyse 3rd-generation cephalosporins, so these must NOT be used even if the lab reports apparent susceptibility. Piperacillin-tazobactam is not a reliable first-line agent for serious ESBL infection (inoculum effect, variable outcomes), so it is not the correct answer.
Key fact: ESBL = plasmid-mediated, hydrolyses 3rd-gen cephalosporins; treat serious infection with a carbapenem.
Extended-spectrum beta-lactamases are enzymes that hydrolyse penicillins, oxyimino-cephalosporins (3rd-generation cephalosporins such as ceftriaxone, ceftazidime, cefotaxime) and aztreonam. They are inhibited by clavulanic acid in vitro but this does not translate into reliable clinical efficacy.
Step 2: Statement on carbapenems (TRUE).
Carbapenems (meropenem, imipenem, ertapenem) are the drugs of choice for serious ESBL infections — they are stable to ESBL hydrolysis.
Step 3: Statement on plasmid transmission (TRUE).
ESBL genes (e.g. CTX-M, TEM, SHV) are carried on plasmids, allowing horizontal spread and co-resistance to other antibiotic classes.
Step 4: Why piptaz and 3rd-gen cephalosporins are wrong.
By definition ESBLs hydrolyse 3rd-generation cephalosporins, so these must NOT be used even if the lab reports apparent susceptibility. Piperacillin-tazobactam is not a reliable first-line agent for serious ESBL infection (inoculum effect, variable outcomes), so it is not the correct answer.
Key fact: ESBL = plasmid-mediated, hydrolyses 3rd-gen cephalosporins; treat serious infection with a carbapenem.
Was this answer helpful?
0
0
Top INI CET Microbiology Questions
- Which of the following bacteria is the most common cause of community-acquired pneumonia?
- Which of the following bacterial toxins acts by inhibiting elongation factor 2 (EF-2)?
- A patient presents with septic arthritis. Culture grows a Gram-positive coccus that is catalase positive and cefoxitin sensitive. What is the drug of choice?
- A poorly controlled diabetic patient presents with facial pain and a black eschar over the nasal/palatal region. Which organism is most likely responsible?
- Which bacterium possesses two circular chromosomes?
View More Questions
Top INI CET Questions
- Which of the following is the most common cause of acute pancreatitis?
- Which of the following conditions is most commonly associated with hypoparathyroidism?
- The drug of choice for treating acute gout flare is:
- Which of the following bacteria is the most common cause of community-acquired pneumonia?
- Which of the following is the hallmark of Type 1 Diabetes mellitus?
View More Questions