title: Development and evaluation of a new growth medium for Helicobacter pylori.
abstract: The present study was aimed at modifying the original formulation of Commercial Eugon agar (CEA) to develop a new H. pylori growth medium. Initial studies were carried out to determine the number of H. pylori colonies recovered on in-house H. pylori agar (IHPA), IHPA without L-cysteine and sodium sulfite (IHPA-NC), IHPA without L-cysteine (IHPA-C), IHPA without sodium sulfite (IHPA-N) and CEA as the control. Significant differences (P < 0.001) in the number of colonies recovered were observed between IHPA-N, IHPA-NC and IHPA-C. Incorporation of sodium sulfite decreased the number of colonies recovered, indicating that sodium sulfite was inhibitory to H. pylori growth. Removal of L-cysteine reduced the number of colonies recovered, suggesting that L-cysteine is necessary for the growth of H. pylori. In the subsequent study, incorporation of K(2)HPO(4) further increased the number of colonies recovered compared with IHPA-N (P < 0.001), and 0.25% (w/v) of K(2)HPO(4) yielded the highest numbers of colonies (P < or = 0.04). Finally, thirty other H. pylori clinical isolates were evaluated for their growth in the IHPAP-N, a new medium consisting of 1.5% (w/v) pepticase, 0.5% (w/v) peptone, 0.4% (w/v) sodium chloride, 0.03% (w/v) L-cysteine, 0.55% (w/v) dextrose, 0.25% (w/v) K(2)HPO(4) and 1.5% (w/v) agar. The number of colonies recovered in IHPAP-N was significantly (P < 0.005) higher than that of CEA. IHPAP-N with 0.25% K(2)HPO(4) and without sodium sulfite were adequate solid media for the growth of H. pylori.
authors.affiliation: School of Biological Sciences, University of Science Malaysia, Pulau Penang, Malaysia. srisasidharan@yahoo.com
authors.forename: Sreenivasan
authors.initials: S
authors.lastname: Sasidharan
authors.forename: Abdul M
authors.initials: AM
authors.lastname: Uyub
mesh_terms: D000362:Agar; D001431:Bacteriological Techniques; D015169:Colony Count, Microbial; D003470:Culture Media; D003545:Cysteine; D005947:Glucose; D016480:Helicobacter pylori / Q000254:growth & development*; D010461:Peptones; D010710:Phosphates; D017680:Potassium Compounds; D012965:Sodium Chloride; D013447:Sulfites
chemical_list: D003470:Culture Media; D010461:Peptones; D010710:Phosphates; D017680:Potassium Compounds; D013447:Sulfites; D012965:Sodium Chloride; D000362:Agar; C013216:potassium phosphate; D005947:Glucose; D003545:Cysteine; C025026:sodium sulfite