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超抗药淋球菌
作者:dokknife
发表时间:2011-07-12
更新时间:2011-07-12
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日本超级淋病没药可医 或迅速向全球扩散 世界日报


科学家在日本发现全球首见的超级淋病病菌,对所有治疗淋病的抗生素都有抗药性。这种代号H041的超级病菌,恐使过去轻易可治癒的淋病成为全球性公卫威胁。

淋病是由淋病双球菌引起,主要经由性交传播。现有各种淋病疗法,对新变种的H041淋病双球菌均莫可奈何,可能迫使医学界只能以未经实际验证的碳青霉烯类抗生素尝试治疗,但效果未知。

瑞典病原性淋病双球菌参考实验室的乌内莫与日本学者合作,在京都采集的检体样本中发现H041。他表示,这项最新发现「令人震惊」却「可以预料」。他说:「抗生素1940年代成为治疗淋病的标准药物后,这种病菌即已发展出足以对抗各种药物的机制。目前仍无法断言这种新病菌是否已扩散,然而病菌产生抗药性的纪录显示,如果医学界未能及时研发新药及有效的疗法,它可能迅速扩散。」

研究发现,H041对治疗淋病的最后防线头芽孢菌素抗生素具有极强的抗药性,医药界目前只能用号称历来最强效的碳青霉烯类抗生素尝试治疗,然而乌内莫强调,这种药从未用于治疗淋病,效果有待观察。

乌内莫指出,科学家在日本发现H041之余,也发现另一项惊人的模式。他说:「长久以来,日本一直是各种抗药性淋病病菌首次出现的地区,病菌随后就扩散到全球。」他说,根据过去的模式,抗药性淋病会在10年至20年内在国际间扩散。研究结果11日在加拿大魁北克举行的国际性病研究学会学术会议中发表。

淋病是全球最普遍的性病之一,女性感染者半数不会出现症状,男性也有2%至5%不会出现症状。如未经适当治疗,淋病可对妇女造成骨盆发炎、异位妊娠、不孕等后果。淋病在南亚、东南亚、撒哈拉沙漠以南的非洲地区最普遍。香港、中国大陆、澳洲及亚洲其它地区的卫生当局近年来都发现对某些抗生素具有抗药性的淋病病例,且数量明显增加,但从未出现过像H041这样能抵抗所有抗生素的淋病病菌。


Scientists Discover Drug-Resistant Gonorrhea 'Superbug'
By Laura Blue Monday, July 11, 2011 | 7 Comments

http://healthland.time.com/2011/07/11/scientists-discover-drug-resistant-gonorrhea-superbug/


The finding was presented Monday with extensive laboratory evidence at a conference in Quebec City, Canada — and it comes just three days after the Centers for Disease Control and Prevention (CDC) warned that U.S. gonorrhea samples had being showing new signs of drug resistance as well. Although drugs have remained effective in almost all U.S. cases, the CDC said that analysis of bacteria samples taken from 2000 to 2010 showed that the gonorrhea bug was becoming less and less susceptible to the frontline drugs, cephalosporins, as the years went by.

"This is both an alarming and a predictable discovery," Dr. Magnus Unemo said in a statement about H041. Unemo, based at the Swedish Reference Laboratory for Pathogenic Neisseria, worked with Japanese colleagues to characterize the new H041 multidrug-resistant gonorrhea strain.

Multidrug resistance is "predictable," in Unemo's words, because most gonorrhea strains worldwide are already resistant to at least one major class of antibiotics. Bacteria become resistant to antibiotics through evolution. Some naturally occurring genetic variation exists among Neisseria gonorrhoeae, the bacterial organism that causes gonorrhea, and that means that any one given bacterium may, by chance, be slightly more susceptible to antibiotics than another. When a colony of bacteria first comes in contact with antibiotics, therefore, the antibiotics will kill off the most susceptible bacteria at higher rates. This leaves behind a disproportionately robust batch of surviving bacteria, and when the survivors reproduce, they pass on their more-robust-than-average genes to their offspring. With repeated exposure to antibiotics, and over many generations of bacteria, eventually all the bacteria that are spreading are drug-resistant.

In the U.S., gonorrhea strains resistant to penicillin and tetracycline have been circulating since the 1970s and became widespread by the early 1980s, according to the CDC. Since then, most Neisseria gonorrhoeae have also become resistant to fluoroquinolines, and today the CDC recommends treating gonorrhea with both a cephalosporin and either azithromycin or doxycycline (two relatively commonly administered antibiotics).

But the recent CDC report from last week suggests that some U.S. samples of Neisseria gonorrhoeae are no longer responding quite as well as they used to against cephalosporins either — the bacteria have become less susceptible — and now the new strain in Japan is reportedly resistant to everything.

That brings us back to what researcher Magnus Unemo called "alarming." Gonorrhea is by no means the most deadly of sexually transmitted infections. But it is among the most common — with 700,000 new cases in the U.S. each year, and an estimated 340 million new cases each year globally.

The disease often causes painful intercourse (among women), tender and swollen testicles (among men), and pain when urinating (among infected people of both sexes). Left untreated, gonorrhea can lead to internal scarring of parts of the reproductive tract and, in women, pelvic inflammatory disease or lifelong infertility.

"The potential emergence of gonococcal cephalosporin resistance is of particular concern because the U.S. gonorrhea control strategy relies upon effective antibiotic therapy," the CDC announced Friday. "No other well-studied and effective antibiotic treatment options or combinations currently are available [once the bacteria are resistant to cephalosporins]."

As for H041, the strain found in Japan: "While it is still too early to assess if this new strain has become widespread, the history of newly emergent resistance in the bacterium suggests that it may spread rapidly unless new drugs and effective treatment programs are developed," Unemo said in his statement.

Indeed, when researchers grew the drug-resistant bacterium in culture with other strains of gonorrhea, the new strain was able to pass its resistance quickly, increasing the other strains' resistance to cephalosporins some 500-fold. That suggests that H041 could spread resistance swiftly in the real world.

Related Topics: antibiotic-resistance, cephalosporins, drug resistance, gonorrhea, H041, Infectious Disease, Medicine, Neisseria gonorroeae, superbug More ways to get Healthland



Read more: http://healthland.time.com/2011/07/11/scientists-discover-drug-resistant-gonorrhea-superbug/#ixzz1RuDRYcr4

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