We have recently isolated a strain, which is a gram variant strain showing mucoidal colony morphology on nutrient agar plates and which glows (luminescence/ fluorescence) when viewed under UV light. The fluorescence was remarkably found around the colonies, when centrifuged the property was found to be in the supernatant. IMViC results were like -+++, non- lactose fermenting, and showed acid + gas on sugar like Glucose, Mannitol and Sucrose, urease positive and citrate positive.
Someone please suggest what could be the organism, we have given it for sequencing, still curious to know what it could be...
It is possible,because fluorescent activity is dependent on Fe concentration in your medium, but for identification you should blast 16s rRNA if you are sure your isolate is pured. Gram variable isquestionable.
Many bacterial species form fluorescence on agar medium such as B, terreus ,B, fluroscence and others. This is due to the pigments produced and metal concentration of medium. So the phenomena are possible. Try to identify this organism by possible methods.
Do you have UV-vis spectra of the fluorescent compound? It could be useful in determining likely structural elements and thus which organism is present...
It sounds like a siderophore but the most frequently described example of fluorescent siderophores (Pseudomonas / pyoverdine) would be ---+, not -+++ by IMViC.
If you are using an old/expired IMViC kit they can give variable results. If you suspect Pseudomonas, you can do a quick biofilm assay. Not diagnostic, but suggestive.
Take about 200 µl of a low-inoculum (clear) suspension in broth and put it in a well of a 96-well plate (not tissue-culture treated works best). Incubate overnight. When you carefully remove the media with a pipette the next morning, Pseudomonas will usually leave a ring around the well at the air-liquid interface (because it's a strict aerobe).
Various similar protocols have been adapted from George O'Toole's work (www.dartmouth.edu/~gotoole/) which lists media and plastics considerations. It's a quick-and-dirty test but at least it gives you an indication of whether the organism is a strict aerobe or not.
- Badges
- Science topic
- Similar topics
- Biological Science
- Microbiology