Sunday, February 5

Streptococcus A: reasons to worry about the increase in invasive infections

Several European countries have indicated an increase in the year 2022, particularly since September, in the number of cases of invasive group A streptococcal disease (iGAS) among children less than 10 years of age. Specifically France, Ireland, the Netherlands, Sweden and the United Kingdom.

Streptococcus A keeps Spain under “active surveillance” after the death of 15 minors in the United Kingdom from this bacterium


The cause is bacteria Streptococcus pyogenes, colloquially referred to as group A streptococcus (GAS), a common pathogen that predominantly affects the skin, soft tissues, and respiratory tract. It holds the dubious honor of being among the leading pathogens causing global morbidity and mortality, particularly in disadvantaged settings around the world.

When it does not stay in pharyngitis

Group A strep represents the most common cause of bacterial pharyngitis in school-age children. Every year 616 million new cases of pharyngitis by group A strep. GAS infections usually cause a mild illness that includes sore throat, headache, and fever, along with a fine, red rash.

Unfortunately, Streptococcus pyogenes it also causes life-threatening infections including, but not limited to, scarlet fever, bacteremia, pneumonia, necrotizing fasciitis, myonecrosis, endometritis, septic arthritis, post-streptococcal glomerulonephritis, and streptococcal toxic shock syndrome. It is so aggressive because it synthesizes virulence factors that contribute to tissue destruction and the spread of infection.

Approximately 18.1 million people currently have severe group A strep disease, with 1.78 million new cases and 517,000 annual deaths. Most deaths occur within seven days of infection, and the greatest risk of mortality occurs within the first 48 hours.

In addition, group A strep infection is considered the underlying cause of rheumatic fever. These microorganisms are capable of releasing pyrogenic exotoxins that cause redness of the tongue and a bright red rash over most of the body. The disease causes sore throat and high fever, but if it is not treated it can cause complications in the lungs, kidneys, middle ear, tonsils and skin.

More than 200 different serotypes have been described. Streptococcus pyogenes based on the structure of the M protein, known to allow bacterial invasion into human cells, prevent phagocytosis and promote survival in infected tissues. However, fewer than 10 serotypes are predominant in clinically significant invasive streptococcal infections.

Classically, infections are classified as non-invasive or invasive, depending on location and severity. Non-invasive infections include pharyngitis (also known as strep throat), sinusitis, impetigo, ecthyma (skin ulceration), otitis media, scarlet fever (rash caused by toxins), cellulitis, endometritis (especially in pregnant women), and pneumonia. Invasive infections include peritonsillar abscess, myositis, septic arthritis, necrotizing fasciitis, meningitis, bacteremia, and streptococcal toxic shock syndrome.

A mortality rate of up to 16%

Invasive group A streptococcal (iGAS) infection, characterized by entry of the bacteria into sterile body fluids, including blood, has a mortality rate of 8% to 16%. In the UK there have been 851 cases in week 46 of the year, compared to an average of 186 in previous years. The situation is similar in some points of the USA. And so far this season, there have already been 60 kills in all age groups in England. In recent weeks, at least 17 children under the age of fifteen have died in several European countries as a result of the infection.

In cahoots with respiratory viruses

The number of invasive group A streptococcal (iGAS) infections usually shows a seasonal pattern, with peaks during the winter and spring months.

The recent increase in cases of iGAS disease in children is also likely to be associated with the recent increase in circulation of respiratory viruses, including seasonal influenza and respiratory syncytial virus, as virus co-infection with group A streptococcus can increase the risk of disease invasive group A streptococcal (iGAS). Children with viral infections such as chickenpox or the flu are at higher risk of developing iGAS disease.

That does not rule out other factors such as underlying coexisting medical conditions and the types of A strep circulating in the community and immunity against these types in the population.

It spreads easily

The infections caused by Streptococcus pyogenes they are very contagious. The broadcast It can occur through airborne droplets or by hand contact with nasal secretions or with objects and surfaces contaminated with the bacteria. It is also transmitted by skin contact with contaminated lesions or contaminated food.

Common settings that facilitate transmission of the organism and lead to group A strep epidemics include schools, day care centers and kindergartens, hospitals, homeless shelters, nursing homes, and military training facilities. In fact, in schools and residences the transmission is intense.

A simple and effective preventive method is to ensure that children and the elderly wash their hands regularly, especially after coughing or sneezing. Since prevention of viral illnesses is likely to be important in reducing the risk of iGAS disease, it is also timely to promote vaccination against seasonal influenza and covid-19.

when should we worry

The overall mortality rates for all invasive infections due to Streptococcus pyogenes They range between 10 and 20%. However, in specific and specific situations, in some serious invasive infections, such as necrotizing fasciitis and streptococcal toxic shock, mortality rates can increase by up to 80%.

Early signs and symptoms of invasive group A strep (iGAS) infection may include high fever, severe muscle aches, localized muscle tenderness, and sometimes redness at the site of a wound.

If the infection progresses to necrotizing fasciitis, early symptoms may include a rapidly spreading area of ​​red, hot, or swollen skin, severe pain, including pain beyond the area of ​​skin that is red, warm, or swollen, and fever .

Later symptoms of necrotizing fasciitis may include sores, blisters, or black spots on the skin, changes in skin color, pus or oozing from the infected area, dizziness, fatigue, diarrhea, or nausea. In the event that strep toxic shock syndrome occurs, symptoms often begin with fever and chills, muscle aches, nausea, and vomiting. After a period of 24 to 48 hours, hypotension, tachycardia, tachypnea, and organ failure appear.

iGAS infections may initially present with non-specific symptoms (fever, general tiredness, loss of appetite) but, particularly in children, may rapidly progress to severe disease. Therefore, before the initial symptoms appear, it is advisable to request health advice, clinical evaluation and immediate medical attention.

This article was originally published on The Conversation.

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