Comparison of the Efficacy of Egg Yolk Extract and Horse Serum for Growth of Mycoplasma pneumoniae

Abstract

The usefulness of chicken egg yolk extract as a substitute for horse serum in culture media for Mycoplasma pneumoniae was investigated.As a growth-supporting factor in the growth medium for M. pneumoniae and some other mycoplasmal species, the primary isolation medium for M. pneumoniae, and the metabolism-inhibition test medium for diagnosis of M. pneumoniae infection, egg yolk extract may be an excellent substitute for horse serum.The particular superiority of egg yolk extract to horse serum is that egg yolk extract, unlike horse serum, did not show any inhibitory effect on the growth of M. pneumoniae.Conventional culture media for mycoplasmas contain 20 % (v/v) unheated horse serum (HS) (2, 6). As the growth of Mycoplasma pneumoniae is often markedly affected by certain HS preparations, it is important to use HS preparations of suitable quality in the medium for diagnosis of M. pneumoniae infection. Recently SP-4 medium, which contains fetal bovine serum heated at 56 C for 1 hr (11), and modified New York City medium, which contains agamma HS (4, 5), have been introduced as excellent primary isolation media for M. pneumoniae.In our previous study (8), we showed that EY, the supernatant fluid of chicken egg yolk suspension in phosphate-buffered saline, was useful as a serum substitute in mycoplasmal culture media.In the present study, we showed the inhibitory effect of HS on the growth of M. pneumoniae, and compared EY broth medium, which consists of 90 parts of PPLO broth and 10 parts of EY, with Chanock medium (2), which contains20 parts of unheated HS, for their ability to support the growth of laboratory-adapted strains and clinical isolates of M. pneumoniae. The latter is a medium used very frequently as one of the conventional growth media for mycoplasmas. MATERIALS AND METHODSMycoplasmas. Of the ,1.5 mycoplasmal strains listed in Table 2,. M. arginini and M. hominis were obtained from Prof. M. Nakamura of Kurume University School of Medicine. The other strains were obtained from Prof. M. Ogata of Azabu University of Veterinary Medicine and have been maintained in our laboratory for 49 9

Conditions for growing Mycoplasma canadense and Mycoplasma verecundum in a serum-free medium

“…Therefore, serum cannot be used as a supplement for mycoplasma growth when membrane research is being done. Although several species of mycoplasmas have been reported to grow in serum-free medium (3,5,11,15), this has not been the case for either M. canadense or M. verecundum. The selection of these species was also based on their temperature range of growth.…”

“…Therefore, growing both species in the same serum-free medium could provide two different in vivo model systems for studying compensatory adjustments of membrane composition, structure, and dynamics in response to altered temperature. Here we report the growth of these two species of mycoplasmas in a serum-free medium supplemented with 0.5% bovine serum albumin, 15 ,ug of cholesterol per ml, and 8 ,ug each of oleic and palmitic acid per ml. mented with 10% fresh yeast extract and 20% (vol/vol) unheated horse serum (Bacto-Mycoplasma Supplement, code 0836; Difco).…”

Utility of Egg Yolk Medium for Cultivation of Some Mycoplasma Species

“…EY agar medium is also useful for the growth of some mycoplasma strains and for characterization of film-spot-forming strains (data not shown). However, EY agar medium made from PPLO broth and some agar preparations is very turbid (6). Therefore, suitable agar products should be selected for the preparation of EY agar medium.…”

A Sensitive Method for Detecting the Fermentation‐Inhibition Antibody to Mycoplasma pneumoniae

“…Because of the difficulty of preventing the decay of complement activity in commercially distributed horse serum and the growthinhibitory effect of the horse serum on Al. pneumoniae (18), this assay does not warrant a satisfactory level of sensitivity and often fails to give consistent results (17). In order to overcome these drawbacks, we developed an assay system employing an optimal amount of guinea pig complement in conjugation with gamma globulindepleted horse serum.…”