How does centrifugation increase yield in fungal (Fungus) cultures?

From the Guidelines

Centrifugation increases yield in fungal cultures by 30-40% through the use of lysis centrifugation, which is a more effective method than conventional blood culture techniques. This is particularly important in the diagnosis of invasive Candida infections, where conventional blood culture techniques are often insensitive, with only 50% of patients with disseminated candidiasis having positive blood cultures 1. The use of lysis centrifugation can help to improve the detection of fungal elements in blood cultures, which is critical for the diagnosis and treatment of fungal infections.

When processing clinical specimens or fungal broths, centrifugation sediments fungal cells, spores, and hyphal fragments to the bottom of the tube, creating a concentrated pellet that contains more fungal elements per unit volume than the original sample. This concentration effect is particularly valuable when dealing with specimens containing low fungal burdens, as it brings dispersed fungal elements together, increasing the likelihood of successful culture growth.

The process typically involves spinning samples at 3,000-4,000 rpm for 5-10 minutes, followed by discarding most of the supernatant and using the concentrated pellet for inoculation onto culture media. Additionally, centrifugation helps remove inhibitory substances present in clinical specimens, such as antimicrobials or host defense factors, which might otherwise interfere with fungal growth. For optimal results, the centrifuged pellet should be resuspended in a small volume of sterile saline or broth before inoculation onto appropriate fungal media, and multiple media types should be used to maximize recovery of different fungal species.

It's worth noting that the use of special blood culture systems, such as lysis-centrifugation, can be helpful in isolating certain pathogens, including fungi, and that communication with the microbiology laboratory is essential to determine whether special culture systems are needed 1. However, the key point is that centrifugation, particularly lysis centrifugation, is a crucial step in increasing the yield of fungal cultures, and its use should be considered in the diagnosis of fungal infections.

Some key points to consider when using centrifugation to increase yield in fungal cultures include:

• The use of lysis centrifugation can increase yield by 30-40% compared to conventional blood culture techniques
• Centrifugation can help remove inhibitory substances present in clinical specimens
• The centrifuged pellet should be resuspended in a small volume of sterile saline or broth before inoculation onto culture media
• Multiple media types should be used to maximize recovery of different fungal species
• Communication with the microbiology laboratory is essential to determine whether special culture systems are needed.

From the Research

Centrifugation in Fungal Culture

• Centrifugation is a technique used to increase the yield of fungal cultures by separating fungal cells or spores from other particles or debris 2, 3.
• The process involves spinning a mixture of fungal cells or spores at high speeds to separate them based on their density and size 4.
• Centrifugation can be used in conjunction with other techniques, such as density gradient centrifugation, to improve the separation and isolation of fungal cells or spores 4, 5.

Effects of Centrifugation on Fungal Yield

• Centrifugation can increase the yield of fungal cultures by concentrating fungal cells or spores and removing impurities 2, 5.
• However, centrifugation can also lead to a loss of fungal cells or spores, particularly if the centrifugation speed or time is too high 3.
• The optimal centrifugation conditions for fungal culture depend on the type of fungus and the specific application 2, 5.

Applications of Centrifugation in Fungal Culture

• Centrifugation is commonly used in the isolation and cultivation of filamentous fungi for various purposes, including enzyme production and molecular microbiology 6.
• Centrifugation can also be used to extract fungal mycelium from soil samples, allowing for the characterization of soil fungal communities 5.
• In addition, centrifugation can be used to concentrate fungal spores from air samples, enabling the study of fungal diversity and exposure 3.