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Updated: Aug 29, 2026
Application of Membrane and Cell Wall Selective Fluorescent Dyes for Live-Cell Imaging of Filamentous Fungi
Published on: November 28, 2019
Nonvalue of culturing cerebrospinal fluid for fungi
Joan Barenfanger1, Jerry Lawhorn, Cheryl Drake
1Memorial Medical Center, Springfield, Illinois 62781, USA. barenfanger.joan@mhsil.com
Abstract:
No studies have evaluated the efficacy of culturing cerebrospinal fluid (CSF) for fungi. Because of the facts that the most common fungi responsible for meningitis grow well in media utilized for routine bacterial cultures and that cryptococcal antigen tests are commonly ordered, the efficacy of routinely performing fungal cultures specifically to recover fungi has been questioned. We examined data from 1225 samples of CSF which were cultured for both bacteria and fungi. Twelve specimens yielded fungi, 10 from fungal cultures and 8 from bacterial cultures. Cryptococcus neoformans was found in 10 specimens, Candida albicans was found in 1, and a Cladosporium sp. was found in 1. Eight of 12 positive specimens had concordant culture results. The discordant cases were one specimen that was bacterial culture positive but fungal culture negative and three specimens that were fungal culture positive but bacterial culture negative. Of the latter discrepant cultures, one had fungal contamination only and the other two were positive for cryptococcal antigen. Therefore, omitting the fungal cultures on these specimens would not adversely impact patients. When both cryptococcal antigen tests and bacterial cultures are ordered routinely, eliminating fungal cultures on CSF would have had no impact on the patients in this study. All the clinically significant fungi were detected by the cryptococcal antigen test and/or bacterial culture. With a few exceptions, the combined use of cryptococcal antigen test and bacterial cultures of CSF could replace routine fungal cultures of CSF. Exceptions include settings where fungal pathogens other than Cryptococcus and Candida remain important causes of meningitis.
Insights
Routine fungal cultures of cerebrospinal fluid (CSF) may not be necessary. Combined cryptococcal antigen tests and bacterial cultures detect most fungal meningitis pathogens, potentially improving patient care efficiency.
Area of Science:
- Medical Mycology
- Clinical Microbiology
- Infectious Diseases
Background:
- The diagnostic utility of routine fungal cultures for cerebrospinal fluid (CSF) is largely unevaluated.
- Common fungal meningitis pathogens grow in standard bacterial culture media.
- Widespread use of cryptococcal antigen tests prompts re-evaluation of dedicated fungal CSF cultures.
Purpose of the Study:
- To assess the efficacy of routine fungal cultures of CSF compared to bacterial cultures and cryptococcal antigen testing.
- To determine if omitting fungal CSF cultures impacts the detection of clinically significant fungi.
Main Methods:
- Retrospective analysis of 1225 CSF samples cultured for both bacteria and fungi.
- Comparison of fungal recovery rates between fungal and bacterial cultures.
- Correlation of culture results with cryptococcal antigen test findings.
Main Results:
- Twelve CSF specimens yielded fungi; 10 by fungal culture, 8 by bacterial culture.
- Cryptococcus neoformans was the most common isolate (10/12).
- Bacterial cultures and cryptococcal antigen tests detected all clinically significant fungal pathogens, with few exceptions.
Conclusions:
- Routine fungal CSF cultures may be redundant when bacterial cultures and cryptococcal antigen tests are performed.
- Omitting fungal CSF cultures did not adversely affect patient diagnosis in this study cohort.
- Combined bacterial cultures and cryptococcal antigen testing can likely replace routine fungal CSF cultures, except in specific epidemiological contexts.
