Statement of the The National Institute of Public Health

Statement of NIPH on angina and streptococci carries in nurseries

Due to the frequent questions of epidemiologists and pediatricians, the State Health Institute issued a statement on carriage and diseases caused by group A beta-hemolytic streptococci in children's groups. Several very interesting pieces of information emerge from the statement, which relate not only to carriage, but also to the repeated unsuccessful use of antibiotics or possible over-treatment with antibiotics only on the basis that streptococci was laboratory-proven in the person concerned.

Statement on angina and carriage of group A streptococci
^{in kindergartens October 13, 2010 | RNDr. Jitka Motlová, CSc.}

We answer numerous questions from epidemiologists, pediatricians and parents of children - statements about disease and carriage caused by group A β-hemolytic streptococci in kindergartens. The so-called Cervical β-hemolytic streptococci of serological group A (Streptococcus pyogenes) cause respiratory disease - angina (without rash) and fever (angina with rash).
Characteristic exanthema (rash) and subsequent peeling of the skin on the palms and soles are characteristic symptoms of streptococcal fever. Group A streptococci are maintained in the population by frequent person-to-person transmission. If the streptococci does not cause a primary disease, a purulent complication or a late consequence (heart or kidney disease) in a person within about 1 month after attachment to the mucous membranes, the risks for the host are considered negligible.

The infectivity of the host to susceptible surroundings also decreases rapidly. In a collective (e.g. a kindergarten) or a closed population with a constant composition, each streptococci "wears out" over a certain period of time and eventually disappears. In the immediate vicinity of teachers, streptococci can be detected on their linen, in the air, in dust, on objects, etc. They can remain viable for months in a dry state. The significance of these so-called secondary reservoirs is practically negligible for the spread of respiratory infections. The occurrence of late consequences in the Czech Republic is in the per thousand values. An individual's susceptibility to angina changes with age. Diseases are rare in quite young children, from preschool age at least to the younger age groups of adulthood, the susceptibility is high, it starts to decrease after the age of 40, also due to the low exposure of these people to streptococcal infections. Type-specific antibodies protect against disease caused by group A streptococci.

Due to the wide spectrum of their type antigens (more than 120), which are the impetus for the formation of antibodies, this method of protecting the organism against infection is very limited. In contrast to the characteristic symptoms of streptococcal fever, the symptoms reported as typical for streptococcal angina can also be caused by other pathogens. Approximately 80% of angina is of viral origin, in the remaining 20% angina caused by group A streptococci predominates (approx. 1/3 of these 20%). The diagnosis of a respiratory disease is further complicated by infections occurring atypically, with minimal symptoms or completely asymptomatically (without symptoms). Therefore, the clinical estimate of the causative agent of the disease must always be supplemented by a bacteriological culture examination - a swab from the tonsils (neck). Streptococcal respiratory disease is typical in most cases of a rich culture of group A streptococci in the throat, in potential carriers and on the nasal mucosa. However, the finding of group A streptococci in angina by itself does not prove the streptococcal origin of the disease due to relatively frequent carriage. In children (especially 5-9 years old) and young individuals in close groups, the carrier rate can reach 20-30%.
Streptococcal infection can be safely distinguished from carriage only retrospectively by demonstrating an increased level of two group A streptococcal antibodies - antistreptolysin O and antideoxyribonuclease B.

If the finding of streptococci is not a manifestation of an active streptococcal infection, it is not a dangerous source of streptococcal infection and late consequences either. The aim of the treatment of the disease is mainly the timely eradication (removal) of streptococci, which is the basis for the prevention of late streptococcal consequences.
Penicillin still remains the most effective antibiotic for treating streptococcal infections. For the survival of streptococci after penicillin treatment, of the whole range of factors considered (insufficient dose and/or insufficient time of antibiotic administration, local factors in the affected tissue, survival of streptococci in tissue cells or tonsil crypts, susceptibility of the individual, etc.), the most significant phenomenon is the persistence of a relatively small number of cells in the resting stage of division.

For the above reasons, a control examination after the end of treatment can show the presence of streptococcus of the same type in about 5% of cases. It is usually impossible to distinguish whether it is reinfection from contacts or survival of the original strain. It is known that slow-growing carrier strains are more difficult to eliminate with penicillium than fast-growing strains in the acute phase of infection. If there has been a recurrence of the disease with a new presence of streptococci, or a rich culture of group A streptococci is demonstrated after treatment and there is a special reason for a new attempt at eradication, repeated administration of penicillin is recommended. If the streptococci "survive" even this treatment, according to experience, there is only a small hope for the success of the third attempt.

At the same time, it is likely that from the beginning they were carriers and diseases caused by another pathogen. But even if the original disease was streptococcal, after two treatment attempts, the risk of late consequences and the contagiousness of the surrounding environment have subsided to such an extent that there is no reason for further intervention. In addition to this failure to eradicate streptococci, however, the administration of antibiotics also has serious risks for individuals, i.e. the elimination of the normal oral microflora, which includes a whole range of bacterial genera and species producing substances and containing structures that protect against the strain's attachment to the mucosa, which is the first step that allows the continuation of the next stages of development disease.

The primary source of infection can be not only a member of the collective, but also persons from the ranks of parents, siblings, relatives, friends and others. In order to catch all possible sources of infection, it would therefore be necessary to perform a bacteriological examination (including the identification of the type of strain) and to treat these persons with antibiotics at the same time as the carriers of the collective.

This procedure, which is very costly in terms of organization and finances, is practically impracticable and therefore not recommended. With the possibility of carriage of various types of group A streptococci, there would be a risk of repeated and unnecessary administration of antibiotics. A different situation may arise if there is an epidemic of streptococcal disease with consequences. Whether it is an epidemic will be assessed by an epidemiologist based on the number of diseases, the number of people in the collective and the period for which the disease has been present.

RNDr. Jitka Motlová, CSc. Head of the reference laboratory for streptococci CLČ OML State Health Institute Prague 12 October 2010
Source: SZÚ (State Health Institute of the Czech Republic)