今日の話題は耐性菌に関する英語記事です。出典は例によってMedical News Todayです。私の拙い和訳を載せています。


Bacteria are becoming resistant to alcohol-based disinfectants.


Antibiotic-resistant bacteria and antifungal-resistant fungi are a worrying phenomenon. According to a recent study, a new concern may be developing: alcohol-tolerant bacteria.


A number of bacteria species are already resistant to a range of antibiotics; the infections they cause are difficult to treat, posing an ever-increasing threat to patients and staff.


Because of the growing numbers of so-called superbugs, hospitals have introduced more stringent cleaning routines.


Part of the regimen involves alcohol-based disinfectants, such as hand rubs, positioned in and around hospital wards. Since their introduction, there has been a significant reduction in the number of hospital-based infections.


Containing 70 percent isopropyl or ethyl alcohol, alcohol-based hand rubs kill bacteria quickly and effectively.


Over recent years, researchers have noted a steady rise in the number of serious infections caused by one particular drug-resistant bacterium — Enterococcus faecium. Despite the wide use of alcohol-based disinfectants, E. faecium is now a leading cause of hospital-acquired infections.

ここ数年、研究者たちは特定の薬剤耐性を示すEnterococcus faeciumによる重大な感染がその数を安定して増していることに注意してきた。アルコール性の消毒液が広く使われているにも関わらず、Enterococcus faeciumは院内感染の主な理由となっている。

Dr. Sacha Pidot and his colleagues at the University of Melbourne in Australia set out to understand whether this increased infection rate might be because the bacterium is growing resistant to alcohol. Their findings were published this week in the journal Science Translational Medicine.

オーストラリア・メルボルン大学Sacha Pidot医師と彼の同僚たちはこの感染率の増加がその微生物(Enterococcus faeciumね)がアルコールに対する耐性を獲得しつつあるからではないかどうか把握することに乗り出した。彼らの発見は今週発行されたthe journal Science Translational Medicineに掲載されている。

To investigate, the researchers used bacterial samples from two hospitals in Melbourne — Austin Health and Monash Medical Centre. In all, they tested 139 samples of E. faecium, isolated from 1997–2015. They assessed how well each sample tolerated diluted isopropyl alcohol.

調査のため、研究者たちはメルボルン市内の2病院ーAustin Health and Monash Medical Centreーから得た菌のサンプルを用いた。全部で139の、1997年から2015年の間に単離されたE. faeciumのサンプルを調べた。研究者たちは、菌がどの程度希釈したイソプロピルアルコールに耐性を示すか評価した。

After analysis, it became clear that the samples taken after 2009 were significantly more tolerant of alcohol than those taken before 2004.



In a second experiment, they allowed bacterial samples to grow on the floors of mouse cages that had been cleaned using alcohol-based disinfectants. Mice were placed in the cages for 1 hour before being moved to clean cages for a further 7 days. After that time, they were screened for infection.


The researchers found that the more recently isolated, alcohol-tolerant strains of E. faecium colonized the resident rodents more successfully.

研究者たちは、より最近単離されたアルコール抵抗性のE. faeciumの菌株が住み込みの齧歯類を植民地化することにより多く成功した。(マウスにちゃんと感染できて菌が繁殖できたってことですね)

To round off their investigation, the scientists delved into the genome of E. faecium. They found that the strains that were more resistant to alcohol displayed mutations in certain genes involved in metabolism; these genetic changes appeared to be responsible for their more hardy constitution.

研究を締めくくるため、科学者たちはE. faeciumのゲノムを徹底的に調べた。その結果、よりアルコール抵抗性のある菌株は代謝に関連する遺伝子に変異があり、これらの遺伝子の変異がより強い抵抗性の形質の理由となっていることがわかった。

Because this study focused on samples from just two hospitals in one city, the authors are wary of the limitations and call for further investigation. Although these are early findings, it is important to consider what alcohol-resistant bacteria could mean in real-life clinical settings.


The development of alcohol-tolerant strains of E. faecium has the potential to undermine the effectiveness of alcohol-based disinfectant standard precautions."

Dr. Sacha Pidot

アルコール耐性をもつE. faeciumの菌株の発達はアルコール性消毒剤による標準的な予防の効果を弱体化させるおそれを秘めている。

(Dr. Sacha Pidot)

Bacteria predate us by millennia; they have survived countless global disasters. Their ability to adapt has been tested and honed over trillions of generations. They seem capable of crossing any flimsy barrier that humans put in their way.

Because the potential ramifications of this study are serious, more studies are likely to be published over the coming months.