Quote:As Japan sees a surge of international tourists during the summer holiday season, health officials are dealing with an outbreak of infections caused by what’s commonly known as “flesh-eating bacteria.” On the program “Health 1+1,” Xiaoxu Sean Lin, an American virology expert and microbiologist, discussed the symptoms, characteristics, and prevention methods for these types of infections.
The “flesh-eating bacteria” recently reported in the news actually refers to group A streptococcus, Lin said. In severe cases, this infection releases enzymes that dissolve muscle and connective tissues, hence its name. These severe cases can lead to conditions including streptococcal toxic shock syndrome (STSS), which has a mortality rate of up to 30 percent.
As of June 30, Japan has reported 1,144 cases of STSS this year, according to a report by the Japanese newspaper Yomiuri Shimbun. This is the highest number of cases in nearly 25 years. Government statistics show that, over the past five years, the annual number of STSS cases has typically been below 1,000. In 2019, there were 894 cases, which decreased to a low of 622 in 2021. However, the number rose again, with 941 cases reported in 2023.

The number of severe Group A streptococcal infections in the United States has been rising over the past decade, data from the U.S. Centers for Disease Control and Prevention (CDC) shows. In the last five years, the U.S. has recorded an estimated 20,000 to 27,000 cases of invasive group A streptococcal infections each year, resulting in 1,800 to 2,400 deaths annually.
The increase in group A streptococcal infections is linked to the COVID-19 pandemic, which has weakened the immune systems of many people, Lin said. With the easing of pandemic restrictions, people are now being re-exposed to a higher number of pathogens. Those with weaker immune systems are at a greater risk of developing severe infections from group A streptococcus bacteria.
Symptoms of Streptococcal Toxic Shock Syndrome
Early symptoms of STSS include:

• Fever and chills
  
• Muscle aches
  
• Nausea and vomiting
  

Severe symptoms may develop within 24 to 48 hours of initial infection, including:

• Low blood pressure
  
• Tachycardia (rapid heartbeat)
  
• Tachypnea (rapid breathing)
  
• Organ failure: Kidney failure may present as an inability to urinate, while liver failure can cause significant bleeding or bruising, and jaundice (yellowing of the skin and eyes).
  

STSS occurs when toxic proteins from group A streptococcus enter the bloodstream and trigger a systemic response, Lin said. These proteins can induce a cytokine storm, leading to widespread blood vessel dilation and a sudden drop in blood pressure. This can, in turn, result in shock and insufficient blood supply to various organs.
Once STSS develops, it can progress rapidly, causing severe symptoms and potentially leading to death. Early diagnosis and treatment are crucial, Lin said. The good news is that group A streptococcus has low antibiotic resistance, making many antibiotics effective.
Characteristics of Necrotizing Fasciitis