Quality Control

Positive: Lysine Ornithine Arginine Base Negative: Lysine Ornithine Arginine Base

Klebsiella pneumoniae Enterobacter cloacae Enterobacter cloacae

Enterobacter cloacae Klebsiella pneumoniae Klebsiella pneumoniae Klebsiella pneumoniae microbiologist should think of Pasteurella multocida, EF-4a, and EF-4b if the isolate is gram-negative and Staphylococcus hyicus and Staphylococcus intermedius if the organism is gram-positive.

The most important point to remember when attempting to group and identify any microorganism is that no piece of information should be overlooked. In this era of cost containment, it is more important than ever to take a stepwise approach to microbial identi fication, beginning with the simplest procedures and proceeding to more expensive definitive testing only if the clinical situation warrants further work. The days of going from a quick glance at a colony on a plate to a rapid identification system without a Gram stain, cata-lase, or oxidase test are over. Microbiologists are going back to basics. The real challenge is how to most efficiently and effectively bring all the information together in a cost-effective and clinically relevant manner.

Figure 13-13

DNA hydrolysis. A, Positive, Staphyiococcus aureus. B, Positive, Serratia marcescens. C, Negative.

dna Hydrolysis principle

This test is used to determine the ability of an organism to hydrolyze DNA. The medium is pale green because of the DNA-methyl green complex. If the organism growing on the medium hydrolyses DNA, the green color fades and the colony is surrounded by a colorless zone.

Figure 13-13

DNA hydrolysis. A, Positive, Staphyiococcus aureus. B, Positive, Serratia marcescens. C, Negative.

method

  1. Inoculate the DNase agar with the organism to be tested and streak for isolation.
  2. Incubate aerobically at 35° C for 13 to 24 hours.

Was this article helpful?

0 0
Bacterial Vaginosis Facts

Bacterial Vaginosis Facts

This fact sheet is designed to provide you with information on Bacterial Vaginosis. Bacterial vaginosis is an abnormal vaginal condition that is characterized by vaginal discharge and results from an overgrowth of atypical bacteria in the vagina.

Get My Free Ebook


Post a comment