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Antibiotics (antibacterial drugs) are essential for the treatment of bacterial infections such as pneumonia, but drug-resistant bacteria that are ineffective against antibiotics are increasing and are becoming a global threat. We will summarize the mechanisms, causes, and countermeasures of drug resistance. Drug resistance has been confirmed not only in bacteria, but also in viruses and parasites, but this time we will focus on bacteria.

Drug resistance refers to bacteria becoming resistant to the effects of antibiotics, making them less effective or no longer effective. Resistant bacteria develop genetic mutations that allow them to evade the mechanism of action of antibiotics, making them impossible to kill. The mechanism by which bacteria acquire drug resistance is
① Produces enzymes that decompose antibacterial substances and cause them to lose their activity
② Change the structure of bacteria and inhibit the action of antibacterial substances
③ Excretes antibacterial substances from within bacteria
④Make it difficult to pass through the membrane and prevent antibacterial substances from entering the bacteria
etc. are known.

It is estimated that more than 1 million people die each year worldwide due to drug-resistant bacteria, and in 2014 the British government announced that the number of deaths due to drug-resistant bacteria is expected to reach 10 million people a year by 2050. Masu. The World Health Organization (WHO) ranks resistant bacteria as "one of the greatest threats to health." Severe resistance has been reported in many bacterial species, including Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus (MRSA), Mycobacterium tuberculosis, and fluoroquinolone-resistant Escherichia coli (FQREC), and according to a 2012 WHO report, the global The penicillin resistance rate of pneumococci is approximately 30%.

In Japan, it has been reported that the penicillin resistance rate of pneumococci in 2021 is approximately 60%, and the detection rate of MRSA is also close to 50%, indicating that major pathogens are becoming resistant. A 2019 domestic study reported that the annual number of deaths in 2017 due to bacteremia caused by MRSA and FQREC, which are among the most common drug-resistant bacteria, was estimated to be more than 8,000. Furthermore, the number of cases that are difficult to treat is said to be increasing, making it a serious health threat, and countermeasures against drug resistance have become an important issue.

The main cause of drug resistance is inappropriate use of antibiotics. If a patient stops taking a prescribed antibiotic midway through, or takes it inappropriately by taking it or not taking it, drug-resistant bacteria may emerge, making the antibiotic less effective. Therefore, it is important to take antibiotics as directed and to make sure to take them all the way to the end. Or doctors prescribe more antibiotics than necessary, causing bacteria to develop resistance to the drugs. Since 2016, the government has taken measures to prevent the unnecessary use of antibiotics, and in 2021, the amount used has decreased by approximately 33% compared to 2013. However, inappropriate prescriptions of antibiotics are still seen in outpatient clinics. Antibiotics are drugs used to treat infections caused by bacteria, so they are not effective against infections caused by viruses such as the common cold, but there are cases in which patients ask their doctors to prescribe antibiotics. Antibiotic use in agriculture and veterinary medicine also contributes to the spread of drug resistance.

The spread of resistant bacteria not only increases the number of people suffering from infections that cannot be treated with drugs, but also threatens to disrupt medical systems such as surgeries and organ transplants. Countermeasures against resistant bacteria require cross-national efforts. WHO has developed a global action plan and provides policy support to countries. In Japan, the Ministry of Health, Labor and Welfare has created an action plan.
・Optimization of antimicrobial use
・Antibiotic research and development and education
・Strengthening international cooperation
We are working on countermeasures based on these points.