PCR分析法可以改善陰道細菌增生症的偵測


  Oct. 10, 2005 (舊金山) - 使用更嚴謹的偵測方法,研究人員可以了解更多會導致陰道細菌增生症(BV)的微生物。
  
  西雅圖Fred Hutchinson癌症研究中心的David Fredricks醫師向Medscape表示,陰道細菌增生症是一種會影響婦女們的常見症狀,全世界皆然;雖然這是一個令人困擾的疾病,但是對於疾病本身而言,我們的了解尚稱足夠。
  
  為了進一步了解,Fredricks醫師的研究小組使用聚合酶連鎖反應分析(PCR)來偵測陰道細菌增生症,此分析法對於導致陰道細菌增生症的微生物而言,具有很高的敏感性及特定性;研究人員發展了一套微生物特定的16 S rDNA PCR分析法來偵測16種陰道微生物,在感染陰道細菌增生症及未染陰道細菌增生症的婦女身上進行微生物增生檢測,PCR分析法可以獲取無法以培養方式獲得的微生物。
  
  Fredricks向Medscape表示,傳統上,通常會以革蘭式染色法進行診斷;但是因為這項方式需要特定的專業訓練,所以醫師們通常不採用;醫師們一般會使用臨床標準(Amsel標準)來對陰道細菌增生症作檢測,如臭味檢驗等。
  
  研究人員對105位婦女的陰道檢體進行PCR分析,根據Amsel標準,其中41位患有陰道細菌增生症,64位沒有。
  
  相較於無陰道細菌增生症者,患有陰道細菌增生症者的16 項PCR分析結果顯示,每一項皆出現明顯不同的陰道微生物增生率;在陰道細菌增生症陽性者中發現,出現的微生物種類包含Gardnerella vaginalis (100% 陰道細菌增生症陽性者皆有,特定性為44%),及Mobiluncus curtisii與Mobiluncus mulieris,後兩者的出現率分別為51%及20%;同時PCR也可以偵測出一些較複雜的微生物,如Megasphaera phylotype, Leptotrichia spp, Eggerthella sp,及Atopobuium spp等;研究人員同時在陰道細菌增生症陽性者身上鑑定出三種新的Clostridiales spp菌種,他們將之歸類為陰道細菌增生症相關微生物;在陰道細菌增生症陰性者身上,明顯被偵測出來的為Lactobacillus crispatus。
  
  奧克拉荷馬大學健康中心的Karen Wendel醫師也發表了類似的研究,也是使用16 S rDNA排序的方式來對19位婦女作診斷(根據Amsel診斷標準,10位無陰道細菌增生症,9位染有陰道細菌增生症);她向Medscape表示,看到了很多Atopobuium vaginae菌種,這可能為婦女們經過抗生素治癒後再度復發的微生物,必須進一步檢測。
  
  Wendel醫師表示,陰道細菌增生症會有復發的問題,而具有metronidazole抗藥性的菌種,如Atopobuium等,皆有可能與復發有關。
  
  Fredricks同意以PCR分析法來偵測陰道細菌增生症,因為這可能有助於確認為何有些婦女們經過治療後還會復發;雖然治療可視為成功,仍然30%的婦女會復發,而原因尚且不明。
  
  Fedricks醫師強調,使用PCR分析來對陰道細菌增生症作測試仍在研究階段;但他表示,他希望這項研究可以為陰道細菌增生症的分子診斷法開啟更多的機會。
  
  對Wendel而言,使用PCR可以對陰道生態作更好的定義;她表示,我們已經使用了很多的診斷方法,但是,如果可以更正確的對不同的細菌作診斷,誤診風險的分級就可以做得更好。

PCR Assays Improve Detection o

By
Medscape Medical News

Oct. 10, 2005 (San Francisco) — With the use of more sophisticated detection methods, researchers are gaining a better understanding of the wide variety of bacterial organisms that cause bacterial vaginosis (BV) in women.

Bacterial vaginosis is a common condition that affects women worldwide, David Fredricks, MD, from the Fred Hutchinson Cancer Research Center in Seattle, Washington, told Medscape, adding that it is a very confusing disease. "There is much we don't understand about the disease," he said.

To learn more about it, Dr. Fredricks and colleagues used polymerase chain reaction (PCR) assays that have a high degree of sensitivity and specificity in identifying vaginal bacteria. To examine bacterial colonization in women with and without BV, the investigators developed bacterium-specific 16S rDNA PCR assays to detect 16 vaginal bacteria. Unlike traditional methods of detection that rely on cultured bacteria, PCR assays can pick up organisms that cannot be cultured.

"Traditionally, diagnosis is made using Gram stains," Dr. Fredricks told Medscape. "However, many physicians do not use this method given the expertise and training needed to do this type of diagnosis." Instead, he said, physicians rely on clinical criteria (Amsel criteria) to check for signs of BV, such as odor.

Using the PCR assays, the authors examined vaginal samples from 105 women. Of these 41 had BV and 64 did not as defined by Amsel criteria.

Compared with the women without BV, women with BV had significantly different rates of vaginal colonization in each of the 16 PCR assays (P < .05 for each assay). Examples of bacteria found include Gardnerella vaginalis (found in 100% of BV-positive women, but specificity was 44%), and Mobiluncus curtisii and Mobiluncus mulieris was found in 51% and 20% of the BV-positive women, respectively. PCR was also able to better detect a number of organisms not as well identified and understood such as Megasphaera phylotype, Leptotrichia spp, Eggerthella sp, and Atopobuium spp. The investigators also identified three new Clostridiales spp organisms in the BV-positive women for which they coined the term BV-associated bacterium. The only bacteria more strongly detected in the BV-negative group was Lactobacillus crispatus.

Karen Wendel, MD, from Oklahoma University Health Science Center in Oklahoma City, presented a similar study using 16S rDNA sequencing to look at the vaginal samples of 19 women (10 without BV and nine with BV by Amsel criteria. She told Medscape that the bacterium "Atopobuium vaginae is showing up in a lot of this work," which suggests to her that it may be a bacterium to examine further to see if it could be related to the fact that many women with BV relapse after antimicrobial treatment.

"BV has a problem with relapse," said Dr. Wendel, adding that particular organisms, such as Atopobuium, which is resistant to metronidazole, could be partially responsible for this.

Dr. Fredricks agreed that using PCR assays to detect BV may be a way to help determine why some women relapse after treatment. "Although treatment is reasonably successful," Dr. Fredricks said, about 30% of women relapse and the reason is unknown.

Use of PCR assays to test for BV is still in the research phase, emphasized Dr. Fedricks, but he said he hopes that this study will "open up new opportunities for the application of molecular diagnosis methods" for BV.

For Dr. Wendel, using PCR can better define what is going on in vaginal ecology. "We've used pretty gross methods up until now," she said, adding that if different bacteria can be more clearly identified, it may help lead to better risk stratification.

IDSA 43rd Annual Meeting: Abstracts 130 and 131. Presented Oct. 7, 2005.

Reviewed by Gary D. Vogin, MD

    
相關報導
子宮切除術後進行壓力型尿失禁手術的風險可能增加一倍
2007/11/2 上午 11:00:00
自我覺察法對尿失禁婦女有效
2007/5/23 下午 03:15:00
罹患卵巢癌婦女數目被低估
2007/4/23 下午 01:31:00

上一頁
   1   2   3   4   5   6   7   8   9   10  




回上一頁