Comparison of agar based media for primary isolation of Helicobacter pylori.
OBJECTIVE
To determine the best medium for the primary isolation of Helicobacter pylori.


METHODS
Sixty six gastric mucosal biopsy specimens frozen in 1 ml Cysteine Albimi media with 20% glycerol from 22 histologically proven H pylori infected patients were cultured on brain heart infusion agar (BHIA) with 7% fresh whole defibrinated horse blood, egg yolk agar (EYA), Columbia blood agar-cyclodextrin agar (CBA-Cd), and commercial trypticase soy agar (TSA) supplemented with 5% sheep blood.


RESULTS
Successful primary isolation of H pylori was 96% with BHIA, 78% with TSA, 64% for EYA, and 32% with CBA-Cd. Colonies appeared earlier on BHIA (4.7 +/- 0.1 days, 5.3 +/- 0.4 days, 5.3 +/- 0.4 days, and 7.1 +/- 0.9 days for BHIA, TSA, EYA, and CBA-Cd) and there were more colonies on BHIA than on CBA-Cd, EYA or TSA (599 +/- 88, 104 +/- 66, 260 +/- 107, and 358 +/- 89, respectively).


CONCLUSIONS
Success of a medium for passage of isolates apparently does not reliably predict usefulness for primary isolation. Freshly made BHIA with 7% horse blood medium is recommended for primary isolation. However, the easily obtainable TSA media would be the best alternative for routine clinical laboratories with no access to BHIA.
Hachem
C Y
CY
Department of Medicine, Veterans Affairs Medical Center, Houston, Texas 77030, USA.
Clarridge
J E
JE
Evans
D G
DG
Graham
D Y
DY
D000362:Agar; D015169:Colony Count, Microbial; D003470:Culture Media / Q000737:chemistry*; D005753:Gastric Mucosa / Q000382:microbiology; D016480:Helicobacter pylori / Q000254:growth & development / Q000302:isolation & purification*; D006801:Humans
D003470:Culture Media; D000362:Agar