Effects of Culture Media On Naegleria fowleri Growth At Different Temperatures.

ABSTRACT

Nelson medium and modified PYNFH medium were used for the axenic culture of the Naegleria fowleri clinical strain LDL to compare the effects of different temperatures on the organism's growth. In addition, Nelson medium supplemented with 1% peptone (N + pep) and modified PYNFH medium without peptone (PYNFH - pep), without yeast extract (PYNFH - yext), without folic acid (PYNFH - folac), and without yeast nucleic acid (PYNFH - yna) were used in order to compare the various effects of these medium components. In general, N. fowleri grew best at 37 C. The highest trophozoite densities per 10,000 µm2 were observed when N + pep and PYNFH - yext were used. At 25, 37, and 43 C, the growth density profile values were 50.5 ± 6.36 vs. 58 ± 1.41; 2,550 ± 494.97 vs. 2,100 ± 141.42; and 1,735 ± 21.21 vs. 1,800 ± 14.14, respectively. On the other hand, PYNFH - pep gave the lowest growth with its highest cell densities being 9 ± 1.41 at 25 C, 108 ± 7.07 at 37 C, and 169 ± 15.55 at 43 C. When the various medium components were compared, supplementation with peptone promoted parasite growth. Besides, yeast extract had an inhibitory effect and was able to swamp the growth promoting effect of peptone. Thus N + pep and PYNFH - yext are recommended as the best media for in vitro culture of N. fowleri.