Q-Eng

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ごく一部、専門用語があるが、全体としてはアニメが面白く判りやすい。
ニュース等でよく出てくる常識範囲の医学用語を覚えるのによいでしょう。　　　　　　　

やや難　　05分・・150wpm　　2014/11/13 新出

字幕：上の動画は開始後 で英語On/Off｡ 日本語選択､文字ｻｲｽﾞはｵﾌﾟｼｮﾝから｡
.　　　　　　　 （YouTubeは 日本語On/Off。 英語選択｡）

★下記英文はマウスオーバー辞書が使えます｡　　　　　　　 　　　　

What if I told you there were trillions of tiny bacteria all around you? It's true. Microorganisms（微生物） called bacteria were some of the first life forms to appear on Earth. Though they consist of only a single cell, their total biomass（生物量） is greater than that of all plants and animals combined. And they live virtually everywhere: on the ground, in the water, on your kitchen table, on your skin, even inside you.

Don't reach for the panic button just yet. Although you have 10 times more bacterial cells inside you than your body has human cells, many of these bacteria are harmless or even beneficial, helping digestion and immunity（免疫）. But there are a few bad apples that can cause harmful infections, from minor inconveniences to deadly epidemics.

Fortunately, there are amazing medicines designed to fight bacterial infections. Synthesized（合成する） from chemicals or occurring naturally in things like mold（ｶﾋﾞ）, these antibiotics（抗生物質） kill or neutralize bacteria by interrupting cell wall synthesis or interfering with vital processes like protein synthesis, all while leaving human cells unharmed.

The deployment of antibiotics over the course of the 20th century has rendered many previously dangerous diseases easily treatable. But today, more and more of our antibiotics are becoming less effective.

Did something go wrong to make them stop working? The problem is not with the antibiotics but the bacteria they were made to fight, and the reason lies in
Darwin's theory of natural selection（ダ-ウｨンの自然選択説 昔は自然淘汰と呼称). Just like any other organisms, individual bacteria can undergo random mutations（突然変異）. Many of these mutations are harmful or useless, but every now and then（時々）, one comes along that gives its organism an edge（有利） in survival. And for a bacterium, a mutation making it resistant to a certain antibiotic gives quite the edge.

As the non-resistant bacteria are killed off, which happens especially quickly in antibiotic-rich environments, like hospitals, there is more room and resources for the resistant ones to thrive, passing along only the mutated genes（遺伝子） that help them do so. Reproduction isn't the only way to do this; some can release their DNA upon death to be picked up by other bacteria, while others use a method called conjugation（接合）, connecting through pili（線毛） to share their genes.

Over time（時を経て）, the resistant genes proliferate（増殖する）, creating entire strains of resistant super bacteria.　So, how much time do we have before these superbugs take over?　Well, in some bacteria, it's already happened. 　For instance,
some strands（DNA鎖） of staphylococcus aureus（黄色ﾌﾞﾄﾞｳ球菌）, which causes everything from skin infections(皮膚感染症)to pneumonia(肺炎) and sepsis（敗血症）, have developed into MRSA, becoming resistant to beta-lactam antibiotics（β-ﾗｸﾀﾑ系
構成物質) , like penicillin, methicillin, and oxacillin.
　（MRSA：Methicillin-Resistant Staphylococcus Aureus メチシリン耐性黄色ブドウ球菌)

Thanks to a gene that replaces the protein beta-lactams normally target and bind to, MRSA can keep making its cell walls unimpeded. Other super bacteria, like salmonella, even sometimes produce enzymes（酵素） like beta-lactams（β-ﾗｸﾏﾀｰｾﾞ） that break down antibiotic attackers before they can do any damage, and E. coli（大腸菌）, a diverse group of bacteria that contains strains that cause diarrhea（下痢） and
kidney failure（腎不全）, can prevent the function of antibiotics, like quinolones, by actively booting any invaders that manage to enter the cell.
　（E. coli [i: 'koulai] ：大腸菌 Escherichia coli [eʃə'rikiə 'koulai] ）

But there is good news. Scientists are working to stay one step ahead of the bacteria, and although development of new antibiotics has slowed in recent years, the World Health Organization has made it a priority to develop novel treatments. Other scientists are investigating alternate solutions, such as phage therapy（ファージ療法） or using vaccines to prevent infections.
　（ファージ療法：Bacteriopharge 細菌を食うウイルス を利用する。ヒトには未承認｡）

Most importantly, curbing（抑制する） the excessive and unnecessary use of antibiotics, such as for minor infections that can resolve on their own, as well as changing medical practice to prevent hospital infections, can have a major impact by keeping more non-resistant bacteria alive as competition for resistant strains. In the war against super bacteria, deescalation（段階的縮小） may sometimes work better than an evolutionary arms rac