0
We're unable to sign you in at this time. Please try again in a few minutes.
Retry
We were able to sign you in, but your subscription(s) could not be found. Please try again in a few minutes.
Retry
There may be a problem with your account. Please contact the AMA Service Center to resolve this issue.
Contact the AMA Service Center:
Telephone: 1 (800) 262-2350 or 1 (312) 670-7827  *   Email: subscriptions@jamanetwork.com
Error Message ......
ARTICLE |

Unmasking of False-Negative Blood Cultures in Patients Receiving New Penicillins

Judith Carleton, BA; Morton Hamburger, MD
JAMA. 1963;186(2):157-159. doi:10.1001/jama.1963.63710020020023d.
Text Size: A A A
Published online

THE ORIGINAL INVESTIGATIONS of the new penicillinase-resistant penicillins demonstrated that their antimicrobial activity could be destroyed by sufficiently large concentrations of Bacillus cereus penicillinase.1 During the course of experiments dealing with the bactericidal activity of such penicillins, it was essential to antagonize residual antibiotic in subcultures to avoid false-negatives. For this to be accomplished, the actual concentration of penicillinase necessary for this purpose had to be established. This information also could be extended to clinical laboratories where blood cultures are made from patients under treatment with these drugs. We have therefore investigated this problem via a study of ratios of B cereus penicillinase to penicillin required for inactivation of four penicillinase-resistant penicillins. For practical laboratory applications it is probably fortunate that B cereus penicillinase, which is easily obtainable, is more potent than staphylococcal penicillinase against resistant penicillins.1 It is the purpose of this paper to report these studies.

Topics

Sign in

Create a free personal account to sign up for alerts, share articles, and more.

Purchase Options

• Buy this article
• Subscribe to the journal

First Page Preview

View Large
First page PDF preview

Figures

Tables

References

Letters

CME
Meets CME requirements for:
Browse CME for all U.S. States
Accreditation Information
The American Medical Association is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. The AMA designates this journal-based CME activity for a maximum of 1 AMA PRA Category 1 CreditTM per course. Physicians should claim only the credit commensurate with the extent of their participation in the activity. Physicians who complete the CME course and score at least 80% correct on the quiz are eligible for AMA PRA Category 1 CreditTM.
Note: You must get at least of the answers correct to pass this quiz.
You have not filled in all the answers to complete this quiz
The following questions were not answered:
Sorry, you have unsuccessfully completed this CME quiz with a score of
The following questions were not answered correctly:
Commitment to Change (optional):
Indicate what change(s) you will implement in your practice, if any, based on this CME course.
Your quiz results:
The filled radio buttons indicate your responses. The preferred responses are highlighted
For CME Course: A Proposed Model for Initial Assessment and Management of Acute Heart Failure Syndromes
Indicate what changes(s) you will implement in your practice, if any, based on this CME course.

Multimedia

Some tools below are only available to our subscribers or users with an online account.

Sign in

Create a free personal account to sign up for alerts, share articles, and more.

Purchase Options

• Buy this article
• Subscribe to the journal

Related Content

Customize your page view by dragging & repositioning the boxes below.

Jobs
brightcove.createExperiences();