Streptococci A and B are bacteria responsible for many infections, some of which are very serious. Several cases of invasive Streptococcus A infections were reported in France at the beginning of December, including 3 deaths. How can we catch them? What symptoms? Treatments?
[Mise à jour le 7 décembre 2022 à 16h49] Several pediatric cases of invasive infections Group A Streptococcus mainly occurring in children under the age of 10 are reported in several regions in France, in early December, reports Public Health France (Occitanie, Auvergne-Rhône-Alpes, New Aquitaine). This streptococcus is a bacterium that can cause mild infections such as angina or scarlet fever and more seriously so-called “invasive” infections with a risk of death. the December 6, the General Directorate of Health (DGS) reports the death of two children and one adult following an invasive group A streptococcal infection. children were also hospitalized in intensive care. These cases would not have any link between them according to the DGS and “these reports are not probably not due to the emergence of a more virulent strain but rather an unusual increase in the number of cases, linked to different strains”. The doctors were instructed to perform a Streptococcus A Rapid Diagnostic Orientation Test (TROD) systematically in front of a angina and to one throat swab in front of a clinical picture of scarlet fever, in case of negative TROD. the UK also reported an upsurge in cases of invasive group A streptococcal infections in recent days with the occurrence of at least 6 deaths in children.
“A streptococcal infection is a microbial attack because streptococcus is a bacterium (rudimentary unicellular living being that has a metabolism). An infection is characterized by an attack on one or more tissues with generally partial destruction of the infected tissues.“Informs Dr. Stéphane Gayet, Infectiologist and hygienist at the University Hospitals of Strasbourg.This infectious process has two major components: pathogenic bacteria divide quickly and form an invasive critical mass (virulence) and in addition they produce toxins which are very dangerous“ he specifies. There are many bacteria of the genus Streptococcus. Streptococcal A infections (Streptococcus pyogenes) and B (Streptococcus agalactiae) are less frequent now due to high consumption of antibiotics ; however, these streptococci have remained sensitive to antibiotics, so fewer people carry them.
1500 to 2500 invasive streptococcal A infections are recorded each year in France.
Group A streptococcus can be responsible for serious invasive infections as observed in France and the United Kingdom at the end of 2022. In this case, it can cause necrotizing skin infectionspuerperal infections, pneumonia and pleuropneumopathies and meningitisnoted Public Health France. These infections may be associated with streptococcal toxic shock syndrome (STSS). Surveillance of invasive infections, including those related to Group A Streptococcus (Streptococcus pyogenes) carried out by Public Health France is based on the network EPIBAC. EPIBAC data show that invasive GAS infections (group A streptococcus) were in constant increase between 2003 and 2019. Over this period, each year they concerned approximately 1,500 to 2,500 people of which nearly 10% of children under 10 years old. In 2020 the incidence of these infections was decreasing and this trend continued in 2021. “This drop was probably linked to the unprecedented implementation throughout the territory of individual and collective barrier measures as part of the management of the COVID-19 pandemic” valued EPIBAC.
Streptococci A and B are quite similar. They belong to the same group of streptococci. “These are virulent and toxigenic strains, especially streptococcus A“says Dr. Stéphane Gayet. Group A beta-hemolytic streptococcus or Streptococcus pyogenes is specific to the human species. “Its habitat is the back of the throat, therefore the pharynx, and it has a rich pathogenic power“ inform the infectiologist. It is most often responsible for mild non-invasive infections, such as angina, impetigo and scarlet fever. More rarely, it is responsible for serious invasive infections.
Streptococcus B (Streptococcus agalactiae) is not specific to humans even though it is a predominantly human bacterium. It is found in some animals but the exchange with the animal is not very frequent. “Its habitat is the intestine and the vagina” teaches Dr. Stéphane Gayet. It can become dangerous if pregnancy where it can be transmitted to the newborn at the time of delivery and cause serious infections such as meningitis or pneumonia. This is why systematic screening at the end of pregnancy is carried out by vaginal sampling. If positive, an antibiotic is given intravenously to the mother as a preventive measure from the start of labor until birth.
Symptoms depend on location. “Streptococcus A in particular gives very marked signs. Symptoms (what you feel) and signs (what you see) are very noisy: very high fever (39-40•C), chills, pain, deterioration of general condition…“Informs Dr. Stéphane Gayet. “Erysipelas (skin infections) is indicated by widespread redness on a limb or on the face, a very high fever, chills” he indicates.
Streptococci A and B are not commensal bacteria (which physiologically belong to the microbiota). It is not “normal” to have streptococci in our body but people are healthy carriers : they harbor them, tolerate them and do not know it because they do not develop disease but they are contagious. They can transmit streptococcus. “For example, a carrier who has put their hands in their mouth can transmit strep A or B by shaking hands with another person. Anything that goes to the mouth is the primary mode of entry for strep A and B“explains Dr. Stéphane Gayet. “You can be contaminated without knowing it, hence the importance of having systematic hygiene measures: wash one’s hands before touching food, after putting hands in mouth and before putting them in mouth… ” recommends this specialist.
“Contagiousness (time during which a person remains contagious) becomes almost zero after 48 hours of antibiotic treatment“Informs Dr. Gayet.
Very high fever, chills, pain, deterioration of general condition are warning signs.
► Streptococcus A is at the origin of red (erythematous) or red with white dots (erythemato-pultaceous) angina, of scarlet fever, a more serious form of angina. It also leads to skin infections: erysipelasa serious infection that often requires hospitalization, and which is seen more in people with overweight or lymphatic and venous circulation disorders; impetigoespecially in tropical countries. In a more serious invasive infection, streptococcus A is also the origin of sepsis often fatal, including sepsis after childbirth (puerperal fever), dermo-epidermatitis necrotizing (necrotizing fasciitis, necrotizing cellulitis) which occurs mostly in hospital after surgery. There is also streptococcal A pneumonia.
► “Streptococcus B has a slightly less intense pathogenic power. It is especially formidable in newborns.“ teaches the infectiologist. “Newborns can get sepsis after birth due to vaginal contamination when a woman is a carrier of streptococcus B in the vagina, he explains. This is why a vaginal and rectum sample is taken at the end of pregnancy, at the 35th week. If positive, the vagina is temporarily decolonized with antibiotic treatment before labor “says the specialist. Streptococcus B also gives angina and septicemia in adults.
A streptococcal A infection often causes a significant passage of the bacteria in the blood.
“The diagnosis is mainly clinical. A doctor who has experience quickly identifies a streptococcal infection which presents typical clinical signs (high fever, deterioration of general condition, usual locations…)” inform the specialist. There is a test of rapid diagnosis for strep throat (biological test) and blood cultures can be performed. A streptococcal A infection often causes a significant passage of the bacteria in the blood. Of the blood samples (blood cultures) are cultured in flasks to identify the bacteria. Of the local levies (swab and culture) can also be done, for example in case of erysipelas. Usual blood tests (NFS) can detect infection (increased CRP, leukocytosis). In December 2022, following an increase in cases of invasive streptococcal A infections, the DGS asks doctors to carry out a Rapid Diagnostic Orientation Test (TROD) Streptococcus A in front of a angina and to one throat swab in front of a clinical picture of scarlet fever, in case of negative TROD. “A negative TROD is not enough to exclude a streptococcal A infection” specifies the DGS. They can progress to more severe and sometimes resuscitative forms constituting the toxic shock syndrome.
Streptococcal A and B infections are treated with antibiotics. “The best antibiotic is penicillinespecially amoxicillin (CLAMOXYL)“Informs Dr. Stéphane Gayet. The duration of treatment depends on the severity of the disease, from 4 days to three weeks.
To limit the risk of transmission, it is advisable to adopt the same barrier gestures used against winter viruses:
- Hand washing,
- Wearing a mask for people with respiratory infections,
- Sneeze or cough into the bend of the elbow
Thank you to Dr Stéphane Gayet, infectious disease specialist and hygienist at the University Hospitals of Strasbourg.