KAJIAN KEMANDIRIAN DAN PERTUMBUHAN HELICOBACTER PYLORI, DAN EPIDEMIOLOGI JANGKITANNYA DI KALANGAN MASYARAKAT BERBILANG KAUM DI UTARA SEMENANJUNG MALAYSIA

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Date
2002-07
Authors
SREENIVASAN, SASIDHARAN
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· The present study was conducted to : firstly to dertermine the prevalence rate of H pylori infection among endoscoped patients at Hospital Seberang Jaya, Penang; secondly, to develop and evaluate a short term storage and growth medium for H pylori; thirdly, to determine the seroprevalence rate of H pylori infection among healthy blood donors; and finally, to detect the antigenic proteins of excretory antigen with Western blotting and examine whether anti- H pylori lgG and IgA antibodies from H pylori positive patients cross-react with antigens from other common bacterial pathogens. Over a 28-month period, prevalence of H pylori infection among the 697 consecutive endoscoped patient were investigated. Overall, the prevalence rate of H pylori infection was 14.6% with Malays significantly lower compared to non-Malays (p<0.05). Generally significantly higher number of males (p<0.05) were infected compared to females but for a particular race such a trend was observed only among the Malays (p<0.05). Although the prevalence rate increased with the age but the increment was not statistically significant (p>0.05). A new short term storage medium for H pylori containing peptone 0.1% (w/v), yeast extract 0.1% (w/v), sodium chloride 1% (w/v), sodium thioglycollate 2% (w/v), Lcysteine 0.05% (w/v) and agar 0.1% (w/v) was successfully developed. Out of 39 clinical isolates evaluated for survival in the new storage medium, 28 isolates have been XIX in tryptic soy broth + 20% (w/v) glycerol at - 70°C, revived twice and twice before evaluation and considered as old isolates. The remaining 11 fresh isolates which have not been stored at - 70°C but have been subcultured twice evaluation. Evaluation revealed that all the isolates tested could survive for a while significantly higher number of fresh isolates (p<0.05) survived longer for 14 A new growth medium for H pylori containing pepticase 1.5% (w/v), peptone ·0.5% (w/v), sodium chloride 0.4% (w/v), L-cysteine 0.03% (w/v), dextrose 0.55% (w/v), K 2HP04 0.25% (w/v) and agar 1.5% (w/v) was also successfully developed. Growth (based on number of colonies formed) for 19 old and 11 fresh H pylori clinical isolates on this medium+ I 0% (v/v) human blood was higher compared to the commerical eugon agar+ 10% (v/v) human blood at all dilution tested (P<0.05). Over a 9-month period, sera from 5370 healthy blood donors were investigated for anti- H pylori antibodies using in-house IgG-ELISA and IgA-ELISA. Sensitivity, specificity, positive predictive value and negative predictive value of in-house ELISA for the detection of H pylori were 86.1%, 97.1%, 85.3% and 97.7%, respectively. Overall seroprevalence rate was 14.2%. There was no significant difference between the seroprevalence rate across all races and both sexes (p<0.05). Prevalence was also found not to increase with age across all ethnic groups. There was not significant association of seropositivity with ABO blood groups. The present seroepidemiological study revealed that exposure to H pylori is equaly distributed among all the major races in Northern XX ·nsular Malaysia but how this predisposes more non-Malays to be infected as revealed by the endoscopic studies remained unknown and was discussed. By using SDS-PAGE, 20 different proteins were found in the excretory antigens. By Western blotting and absorption studies, there are indications that anti- H. pylori lgA · antibodies directed against 54 kDa, 50kDa and 27 kDa cross-reacted with antigens from other bacteria, and that H. pylori proteins of 99 kDa, 88 kDa and 81 kDa possibly shared ·. similar epitope with antigens of other pathognes not tested in the absorption studies. From ELISA and sbsorption sutdies, this cross-reactivity was found not to significantly affect the performance of in-house ELlS As.
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KAJIAN KEMANDIRIAN DAN PERTUMBUHAN HELICOBACTER PYLORI, DAN EPIDEMIOLOGI JANGKITANNYA
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