A chemical additive in the media changes to a pink color as the pH lowers, providing the Microbiologist a visual cue that E. Salmonella can also grow on MacConkey Agar, but cannot ferment lactose, so no color change will be observed. Finally, there are enriched growth media that contain additional nutrients, very specific combinations and amounts of nutrients, or additives to culture fastidious organisms those with special growth requirements.
Mycoplasmas are the smallest self-replicating bacterial organisms, and do not possess cell walls. They are of clinical concern because many are pathogenic, and can be a serious issue in laboratory and pharmacological cell cultures.
The ability to screen for Mycoplasma is therefore extremely important. Their parasitic nature, very small genome, and lack of a cell wall mean they need very specific nutrient and growth conditions to be recovered in the lab. The USP provides a wealth of information and appropriate uses for the broths and agars encountered.
An experienced Microbiologist, with the appropriate resources in equipment and media, is a powerful ally to ensure the highest quality and safest compounded drug products reach the patient. For more information on growth media, contact ARL at info arlok. Moreover, we reported that the superiority of broth over solid media is also supported by recovery of B. The kind of agar used as a solidifying agent may interfere in the early stages of growth. The growth of motile species such as P. The culture method and medium used influenced the recovery of some BCC samples from distilled water and antiseptic samples.
Low nutrient media as a pre-enrichment step are strongly supported for the compendial test method for BCC detection. In addition, the number of bacteria recovered with different broth media indicated that oligotrophic broth media provide for the highest recovery of BCC. The differences between oligotrophic media and TSB or TSA medium for growth or survival in this study were due to the favorable nutritional composition of oligotrophics, compared to a high nutrition medium.
On the basis of our experiments, R2A and dilutions of TSA constituted better enrichment media for the recovery of BCC from distilled water and antiseptics. In addition, the recovery of microorganisms from distilled water samples and antiseptics increased by using a pre-enrichment medium. Results in this study provide confirmatory data for USP in support of its proposed compendial chapter for BCC detection.
Results from this study clearly demonstrate the utility of using diluted media and enriched cultures with a pre-enrichment step as a superior strategy in the compendial test method USP for BCC recovery and detection [ 45 ]. Furthermore, this study provides a comprehensive data set that supports the USP inclusion of lower nutrient, resuscitative media as suggested previously [ 18 , 20 ]. The manuscript is dedicated to the late Mr. Walter Bond for his seminal research contributions on the recovery of Burkholderia cepacia from nebulizer fluids that stimulated the research presented in this paper as well as to the development of the USP chapter on this subject.
The views presented in this article do not necessarily reflect those of the Food and Drug Administration. Correspondence to: Youngbeom Ahn young. The Burkholderia cepacia complex BCC is capable of remaining viable in low-nutrient environments and harsh conditions, posing a contamination risk in non-sterile pharmaceutical products as well as a challenge for detection.
To develop optimal recovery methods to detect BCC, three oligotrophic media were evaluated and compared with nutrient media for the recovery of BCC from autoclaved distilled water or antiseptic solutions. The recovery of BCC in water or antiseptics was higher in culture broth than on solid media. Results from multiple comparisons allowed us to directly identify significant differences between TSA or TSB and oligotrophic media.
Keywords : Oligotrophic medium, tryptic soy agar or broth, Burkholderia cepacia complex. Table 5. Table 6. E-alert Online Submission Contact us. QR Code. Articles Service. Share this article on :. Metrics CrossRef [2] View [] Download [].
Research article Special Topic Antibiotics. Youngbeom Ahn young. Received : June 12, ; Accepted : August 17, Oligotrophic medium, tryptic soy agar or broth, Burkholderia cepacia complex. Materials and Methods. Bacterial Strains BCC isolated from either persons with cystic fibrosis or from the environment were obtained from the Burkholderia cepacia Research Laboratory and Repository at the University of Michigan [ 20 ].
Plate images of B. Recovery of B. Supplemental Materials. Conflict of Interest. The authors have no financial conflicts of interest to declare.
Article Tools Split Viewer. Contents Figure Table References. Research article J. Figure 1. TSA slants are being used to store and ship bacterial cultures. Tryptic soy agar contains digests of casein and soybean meal. The combination of casein and soy peptones renders the medium nutritious by supplying organic nitrogen, particularly amino acids and longer-chained peptides.
Sodium chloride is added to maintain the osmotic equilibrium and agar is the solidifying agent. Tryptic soy agar TSA is recommended for use as a general growth medium for the isolation and cultivation of microorganisms. Tryptic soy agar supports the growth of nonfastidious as well as moderately fastidious microorganisms.
This medium is recommended for use in the cultivation, storage, maintenance, and transportation of pure cultures of microorganisms.
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