Kirchner Medium with Antibiotics and Calf Serum

Kirchner medium is a liquid medium for the selective enrichment and isolation of Mycobacteria spp from clinical specimens, particularly when the organisms may be present only in small numbers (e.g. CSF and tissue biopsies).  This medium has been enriched by the addition of calf serum as it is a widely used supplement because it is rich in growth factors. The medium is made selective by the inclusion of Polymyxin B, Ticarcillin and Trimethoprim to inhibit other bacteria and Amphotericin B to inhibit yeasts and fungi. It is generally used in conjunction with a solid medium such as Lowenstein Jensen Medium. Specimens from normally sterile body sites may be inoculated without digestion and decontamination. Other specimens should be pre-treated according to standard procedures. The inoculated medium should be incubated at 35-37°C for up to 8 weeks. Kirchner medium should be used in conjunction with a solid medium (e.g. Lowenstein-Jensen medium) in order to accelerate differentiation and identification testing.