Penicillinase Test (Beta-Lactamase Production Test)

Norm of Penicillinase Test (Beta-Lactamase Production Test)

Negative for penicillinase.


Usage of Penicillinase Test (Beta-Lactamase Production Test)

Client on antibiotic therapy for bacterial infections, especially Haemophilus influenzae, Staphylococcus aureus, and Moraxella (Branhamella) catarrhalis. To test for bacterial strains that may be resistant to the penicillin type of antibiotics.


Description of Penicillinase Test (Beta-Lactamase Production Test)

Penicillin and some cephalosporin antibiotics work by attaching to a receptor in the cell membrane of bacteria and inhibiting bacteria cell synthesis. When the receptor/penicillin bond is broken, the bacteria are destroyed. Penicillin's bonding ring is a beta-lactam ring. Certain strains of bacteria may have penicillinase (also called beta-lactamase), an enzyme that destroys the beta-lactam ring of penicillin, making it ineffective against the bacteria. When certain strains of bacteria, including Staphylococcus, Neisseria gonorrhoeae, Haemophilus influenzae, and others, produce penicillinase, drugs such as penicillins and first- and second-generation cephalosporins are rendered ineffective against them. This test is performed to detect the presence of penicillinase on isolates of body substances when penicillin treatment shows no improvement in clinical condition. If test results are positive, the treatment is changed to a penicillinase-resistant penicillin or a cephalosporin such as Augmentin, Unasyn, or Timentin.


Professional Considerations of Penicillinase Test (Beta-Lactamase Production Test)

Consent form NOT required.

  1. For sputum samples, obtain a suction catheter and tubing, a sputum trap, and a suction source.
  2. For wounds or abscesses, obtain a sterile needle, a syringe, and a red-topped tube.
  3. For urine, obtain a straight catheter and a sterile container; or a syringe, a needle, and alcohol wipes; or a clean-catch urine collection kit.



  1. Using a sterile technique, collect at least a 4-mL sample of the particular body substance to be tested.
  2. For sputum, collect the sample directly into a sputum trap by suction.
  3. For wounds or abscesses, aspirate 1 mL through a needle into a syringe and inject it into a red-topped tube.
  4. For urine, obtain the sample by straight catheterization by aspirating through the collection port of an indwelling urinary catheter or by a voided clean-catch technique. See clean-catch collection instructions in the test Body fluid, Routine—Culture.


Postprocedure Care

  1. Write the specimen source, collection time, and recent antibiotic therapy on the laboratory requisition.
  2. Send specimens to the laboratory immediately.


Client and Family Teaching

  1. Deep coughs are necessary to produce sputum rather than saliva. To produce the proper specimen, take in several breaths without fully exhaling each. Then expel sputum with a “cascade cough.”
  2. The necessity of the test is associated with the choice of antibiotic to treat the infectious organism.
  3. Results are normally available within 48 hours.


Factors That Affect Results

  1. Do not contaminate the specimen with surrounding tissue.


Other Data

  1. This test is not routinely performed before penicillin therapy is initiated.
  2. Recent development of a fluorescent developer for use in the laboratory has increased the sensitivity of the test.