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Updated: Jun 23, 2026
Method for the Isolation of Francisella tularensis Outer Membranes
Published on: June 29, 2010
Direct isolation of Francisella spp. from environmental samples
J M Petersen1, J Carlson, B Yockey
1Bacterial Diseases Branch, Division of Vector-Borne Infectious Diseases, National Center for Zoonotic, Vector-Borne and Infectious Diseases, Centers for Disease Control and Prevention, Fort Collins, CO 80522, USA. nzp0@cdc.gov
Aims:
To develop a selective medium for isolation of F. tularensis, F. novicida and F. philomiragia from environmental samples.
Methods And Results:
A selective media, cysteine heart agar with 9% chocolatized sheep blood, containing polymyxin B, amphotericin B, cyclohexamide, cefepime and vancomycin (CHAB-PACCV) was developed and evaluated for growth of Francisella spp. No differences were observed in recovered colony forming units (CFUs) for F. tularensis, F. novicida and F. philomiragia on CHAB-PACCV vs nonselective CHAB. Growth of non-Francisella species was inhibited on CHAB-PACCV. When environmental samples were cultured on CHAB and CHAB-PACCV, only CHAB-PACCV allowed isolation of Francisella spp. Three new Francisella strains were isolated directly from seawater and seaweed samples by culture on CHAB-PACCV.
Conclusions:
CHAB-PACCV can be used for direct isolation of Francisella spp from environmental samples.
Significance And Impact Of The Study:
Francisella spp. show a close association with environmental sources. Future utilization of CHAB-PACCV for isolation of Francisella spp. directly from environmental samples should prove valuable for investigating outbreaks and human infections attributed to environmental exposure.
