Fungi are members of the eukaryotic organism and they are classified into two main groups that is yeast and molds.Those fungi capable of exhibiting this to stages are known as dimorphic fungi. Fungi cell wall is made up of chitin and the cells have both macroscopic as well as microscopic structure.
Lactophenol Cotton Blue reagent is used for staining as well as for wet mounting of fungi
The lactophenol cotton blue abbreviated LPCB wet mount preparation is one of the most widely used method of staining and observing fungi because it is simple to prepare.
The identification of molds is based on the shape, method of production, and arrangement of spores (conidial ontogeny). Lactophenol Blue Solution is a mounting medium and staining agent used in the preparation of slides for microscopic examination of fungi.It intensely stain fungi elements blue.
Principle of Lactophenol Cotton Blue stain
The preparation of Lactophenol cotton blue stain has three components thus
- Lactic acid preserves the cellular structure of fungi and clears the tissue
- Phenol acts as a disinfectant and cotton blue imparts blue colouration to the fungal spores and hyphae
Composition of Lactophenol Cotton Blue stain
The following ingredients are used for the composition Lactophenol cotton blue stain
|Ingredients||In 100 ml aqueous solution|
How to Prepare Lactophenol cotton blue
- Start by placing a drop of Lactophenol Cotton Blue reagent on a clean and dry slide.
- The stain imparts a blue colouration on hyphae.
- By using a nichrome inoculating wire, carefully spread the fungal culture into a thin preparation
- Now place a coverslip on the thin preparation.
- Then place a coverslip edge on the drop and slowly lower it. Avoid trapping air bubbles under the coverslip and allow the stain to act for about 5 minutes.
- Observe under microscope with low power 40X objectives lens for screening in low intensity.
A considerable discoloration of the original fungi material can be obtained by treating it with KOH before staining.
Appearance of Lactophenol cotton blue stain
It has an Ink blue coloured solution
Type of Inoculums
Primarily with pure cultures that’s is clinical samples such as
- nail tissue
Observation and interpretation of Lactophenol cotton blue stain
|Fungal spores and hyphae||pale to dark blue|
Quality Control Organism
|Aspergillus niger||Delicate blue hyphae and fruiting structures with a pale blue background.|
|Trichophyton mentagrophytes||Delicate blue hyphae and fruiting structures with a pale blue background.|
Possible limitation of Lactophenol cotton blue stain
The stain is useful in the recognition and presumptive identification of fungi.It is advice to do some biochemical test in order to observe or identify additional characteristics including colony morphology where appropriate for final identification and conclusion
- Koneman, E.W., et al. Color Atlas and Textbook of Diagnostic Microbiology, J.B. Lippincott Company, Philadelphia, PA.
- Isenberg, H.D. Clinical Microbiology Procedures Handbook. 2nd Edition.
- Jorgensen,J.H., Pfaller , M.A., Carroll, K.C., Funke, G., Landry, M.L., Richter, S.S and Warnock., D.W. (2015) Manual of Clinical Microbiology, 11th Edition. Vol. 1.