Leishmania Lesions Are Amenable to Culture Using Specialized Media
Yes, Leishmania lesions are definitively amenable to culture, and parasite isolation should be attempted using specialized media such as Novy-MacNeal-Nicolle (NNN) medium or RPMI 1640 with 10% fetal bovine serum, with reference laboratory assistance strongly recommended. 1
Culture Methods and Media
Specialized culture media are essential for Leishmania isolation:
NNN medium (Novy-MacNeal-Nicolle) is the traditional biphasic medium used for culturing Leishmania parasites from cutaneous and visceral lesions 1, 2
RPMI 1640 with 10% fetal bovine serum is an alternative culture medium that can be used alone or in combination with NNN medium 1, 3
Microculture methods using capillary tubes with RPMI 1640 + 10% FBS have demonstrated superior sensitivity (71.7%) compared to traditional NNN culture (54.7%) and faster time to positivity (4.2 days vs 5.2 days) 3, 4
Practical Culture Approach
Contact reference laboratories before specimen collection as they provide culture and transport media, and Leishmania are fastidious organisms requiring specialized handling 1, 5
Key reference laboratories include:
- CDC (Centers for Disease Control and Prevention)
- Walter Reed Army Institute of Research (WRAIR)
- WHO reference laboratories 1
Culture characteristics to anticipate:
- Cultures can take weeks to become positive, so therapy is often initiated based on other test results while awaiting culture results 1
- Once isolated, parasites can be identified to species level by DNA-based assays or isoenzyme analysis at reference laboratories 1, 5
Important Caveats
Culture has limited sensitivity despite providing definitive parasitologic confirmation—it is not a highly sensitive diagnostic method compared to molecular assays 1
Multiple diagnostic approaches should be used simultaneously rather than relying on culture alone, including microscopy, molecular detection (PCR), and histopathology 1, 6, 5
Specimen collection technique matters:
- Use sterile technique and avoid leaving residual iodine or alcohol on lesions, which interferes with culture yield 1
- Obtain samples from cleansed lesions after removing cellular debris and eschar 1, 5
- Sample from the ulcer base or indurated edge of active lesions for optimal yield 1
Clinical Utility of Culture
Species identification from culture isolates informs treatment decisions, particularly distinguishing species associated with mucosal leishmaniasis risk (Viannia subgenus including L. braziliensis, L. guyanensis, L. panamensis) 1, 5
Culture provides material for additional testing including drug susceptibility testing and molecular characterization if treatment failure occurs 1