Nitrocefin Disk

Detect β-lactamase production by Neisseria gonorrhoeae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus spp., Enteroccoccus spp., and anaerobic bacteria with Thermo Scientific™ Remel™ Nitrocefin Disk. The β-lactamase enzyme is produced by various organisms and is responsible for their resistance to penicillins and cephalosporins^1,2. Since then, similar enzymes with somewhat different substrate specificities have been identified in various bacterial species. The test methods used to detect β-lactamase include iodometric, acidimetric, and chromogenic procedures^3,4.

Since Abraham and Chain confirmed β-lactamase production by microorganisms to be responsible for antibiotic resistance, similar enzymes have been identified in various species. Some enzymes selectively hydrolyze penicillin class antibiotics (i.e., penicillinases), other enzymes hydrolyze all β-lactamase antibiotics except carbapenems (i.e. cephalosporinases) and some enzymes hydrolyze both⁵.

• Ready to use - Nitrocefin impregnated disks.
• Rapid results
• Conforms to CLSI - Performance Standards for Antimicrobial Disk Susceptibility Tests – (Approved Standard M2-A8 and M11-A5)
• Easy to interpret - With color change

The cephalosporin nitrocefin is the substrate used in this test. β-lactamase hydrolyzes the β-lactam ring of nitrocefin, producing cephalosporanic acid⁶. This results in the pale yellow nitrocefin changing to a pink product upon hydrolysis⁷. Aerobic and anaerobic β-lactamase-producing bacteria affect this color; organisms that fail to produce β-lactamase do not alter the pale-yellow color of nitrocefin within the time limits of test.