臺灣五區域幽門螺旋桿菌血清流行病學研究及水中幽門螺旋桿菌之偵測

Abstract

幽門螺旋桿菌 (Helicobacter pylori) 感染是常見的感染，在開發中和已開發國家，成人幽門螺旋桿菌的流行率分別是80-90%和50%左右。幽門螺旋桿菌是消化性潰瘍疾病、慢性胃炎、胃癌等的主要致病原之一。由於廣泛的流行和臨床上的重要性，幽門螺旋桿菌感染是公共衛生的重要課題，而流行病學研究將提供資訊並應用於上消化道疾病，如消化性潰瘍的預防及處理，和高危險癌症族群如胃癌的篩檢調查及未來預防幽門螺旋桿菌之對策制定：例如何時接受疫苗或何時是幽門螺旋桿菌高初感染年紀，何時應積極治療幽門螺旋桿菌感染等 ; 因此，幽門螺旋桿菌感染流行病學研究及相關危險因子的分析是急迫必須的。台灣目前並無一個完整概括全台灣之有關幽門螺旋桿菌之流行病學調查，為了更完整瞭解全台灣幽門螺旋桿菌流行情況、幽門螺旋桿菌感染的危險因子、母親與嬰兒幽門螺旋桿菌抗體的相關性，並且藉由與1989年所作台灣血清幽門螺旋桿菌陽性率，來比較幽門螺旋桿菌這10年來在各年齡層感染幅度的變化及是否有period effect的存在，我們從1999年1月到1999年7月在台灣的5 個地區，透過系統取樣的方法收集了3644 人的血清及120對母親與嬰兒之血清樣本;並採用enzyme-linked immunosorbent assay(EIA)的方法偵測幽門螺旋桿菌抗體。每個個案需完成一關於基本資料、居住地區、家中小孩和大人人數、飲用水來源、有無上托兒所或給褓母帶、和小孩的主要照顧者等的問卷。在這項研究中，年齡調整後的幽門螺旋桿菌之全台灣血清盛行率是43.9%。幽門螺旋桿菌之血清盛行率在北台灣（台北）、東部（宜蘭）、西北部（桃園）呈現年齡特定的逐步上升，但是，在西部（台中）、南部（高雄）則呈現雙峰曲線的變化。在年齡不到二十歲的族群中，血清盛行率為20%，並有特定地區變異（p<0.001），在西部（台中 37.3%）、南部（高雄34.0%）有較高的陽性率，在北台灣（台北5.0%）、西北部（桃園11.5%）、東部（宜蘭10.1%）的陽性率較低 ; 相較於2186位未被感染的族群，561位感染幽門螺旋桿菌的個案中，男性比率較高（55.7% vs 50.8%，p<0.05），使用地下水/井水/河水為飲用水的較多（30.8% vs 22.7%，p<0.001），居住在西部及南部的較多（73.4% vs 34.5%，p<0.001），家中孩童數較少（2.34 vs 2.49，p=0.001）。小於20歲的個案中，在東北部、西部、南部，有較高比率的人使用地下水/井水/河水為飲用水，尤其是南台灣高達52.4%，且飲用地下水/井水/河水的比率與幽門螺旋桿菌血清陽性率有顯著相關(r=0.32 and p= 0.037)。年齡大於二十歲的血清盛行率為55%，不因不同地區而不同。與林肇堂教授在西元1989年於台灣四大區域幽門螺旋桿菌血清流行病學報告比較，每一年齡層的盛行率，現今都較1989年的為低，從1989 到1999年幽門螺旋桿菌血清盛行率之下降應與社經地位和衛生保健情況之進步相關。此外，在母親抗體對嬰兒抗體的影響分析中，幽門螺旋桿菌血清陽性的媽媽經由胎盤傳給嬰兒的幽門螺旋桿菌血清抗體於嬰兒5個月大時消失。 鑑定幽門螺旋桿菌感染的來源和傳染途徑在預防幽門螺旋桿菌感染是很重要的;幽門螺旋桿菌的感染來源目前仍然不確定，有些流行病學證據顯示，水是一個可能的來源，本研究採用即時聚合酶連鎖反應(real-time polymerase chain reaction) 的方法來偵測環境中的水和飲用水中幽門螺旋桿菌Ure A gene之存在，本實驗水樣本離心抽取步驟及real-time PCR的 recovery efficiency 大約為 50% ,目前採集的水檢體real-time PCR結果是陰性的，雖然是陰性結果，但對偵測水中幽門螺旋桿菌之存在，建立了一個標準流程，以期往後能大範圍全面的篩檢偵測水中幽門螺旋桿菌之存在，尤其是飲用水，以期在預防幽門螺旋桿菌感染上能有所助益。

Helicobacter pylori (H. pylori) infection is common throughout the world, and the prevalence of H. pylori varies between developing and developed countries, where prevalence among adults is typically around 80-90% and 50%, respectively. H. pylori infection is a major factor in the etiology of peptic ulcer disease､chronic gastritis､gastric cancer､gastric mucosa-associated lymphoid tissue lymphoma, and so on. Owing to the widespread prevalence and clinical significance, infection with H. pylori constitutes an issue of major public health importance and H. pylori seroepidemiology study would provide information in the management and prevention of upper digestive disease such as peptic ulcer and survey of high-risk cancer population. It is thus urgent to study seroprevelance of H. pylori in Taiwan and explore the factors associated with H. pylori infection. The previous H. pylori epidemiology reports in Taiwan had limited age range, small location distribution of Taiwan, or incomplete data on the seroepidemiology of H. pylori. In this study, we investigated the seroprevalence and the risk factors associated with H. pylori infection in five different areas covering the eastern, western, northwestern, western and southern Taiwan. Sera of 120 pairs of infants and their mothers, and 3644 people, were collected in Jan-July 1999 in five areas of Taiwan including Taoyuan, Ilan, Taichung, Taipei City and Kaohsiung City. The Helicobacter pylori antibody was detected with EIA (enzyme-linked immunosorbent assay) commercial kit (IBL: immuno-biological immunoassay). All the subjects completed a structured questionnaire regarding demographic data, residential area, numbers of children and adults in a family, travel history, sources of water supply, etc. Statistical analysis was performed using logistic regression and the chi-square test. The overall age-adjusted H. pylori seroprevalence in Taiwan was 43.9%. Age-specific stepwise increase of H. pylori seroprevalence was found in northern (Taipei), eastern (Ilan), and north-western (Taoyuan) Taiwan but a biphasic curve was found in western (Taichung) and southern (Kaohsiung) Taiwan. People younger than 20 years old had H. pylori seropositivity rate of 20.0% with significant geographic variation (p<0.001): higher positive rates in western (37.3%) and southern Taiwan (34.0%) than in northern (5.0%), north-western (11.5%) and eastern Taiwan (10.1%); river/underground/well water used as drinking water source, living in western and southern Taiwan, male gender and less children number in the family were factors associated with H. pylori infection. A significant correlation of H. pylori seropositivity and the rates of drinking river/underground/well water was found (r=0.32 and p=0.037). Higher percentage of people used well/underground/river water as drinking water source in northeastern, western, and southern Taiwan, esp southern Taiwan (52.4%). People aged older than 20 years had overall seroprevalence rate of 55% without geographic difference. Our current study shows that the age-specific seroprevalence of H. pylori in 1999 declined one decade later in comparison with the age-specific seroprevelance in 1989. Socioeconomic status and hygiene condition improvement are assumed to be responsible for the declined H. pylori prevalence. Transplacentally transferred maternal anti-H. pylori IgG disappeared in all the infants by 5 months of age. While the sources of H. pylori infection remain uncertain, epidemiological evidence suggests that water is one potential source. In our study, we thus tried to detect H pylori in water by real-time polymerase chain reaction (real-time PCR). A total of 44 water samples were collected from river/lake/spring/tap/underground water in different areas in Taiwan. H. pylori Ure A gene was examined using real-time PCR after centrifugation and DNA extraction of water samples. The recovery efficiency of serial centrifugation､DNA extraction､and real-time PCR was around 50%. H. pylori was not detected in current water samples. Although negative results, we constructed a standard protocol to detect H. pylori in water and hoped the method be applied in detecting H. pylori in water on large scale, esp the drinking water.