Streptococcus viridans (green streptococcus) is part of the normal microflora of the oral cavity and pharynx and is generally considered to be a non-pathogenic microorganism which does not play an etiological role in the development of pneumonia. However, S. viridans has been described as a causative agent of aspiration pneumonia, lung abscess, infectious endocarditis and invasive disease in immunocompromised patients. In the pathogenesis of pneumonia, in most cases, micro-aspiration of virulent microorganisms is observed, which colonizes the upper respiratory tract. This fact suggests that S. viridans may cause some cases of pneumonia.

In order to describe the clinical characteristics of children with pneumonia in whom S. viridans was isolated from the blood, scientists collected data on five patients admitted to the admissions departments of 2 clinics - at Salvador and north-eastern Brazil. for an observation period of 26 months. The diagnosis of pneumonia was confirmed by radiography.

No clinical or radiological features were found to distinguish these cases from ordinary community-acquired pneumonia in children. In addition, these patients were not immunocompromised, which predisposes to the development of invasive infections caused by S. viridans.

There is no convincing evidence that it was S. viridans that caused the pneumonia, despite the fact that only this microorganism was isolated. The effectiveness of antibiotic therapy was the same as in cases where the antibiotic was prescribed empirically. In vitro S. viridans was sensitive to antibiotics commonly prescribed for the treatment of community-acquired pneumonia.

The microorganism could enter the blood during meals, oral hygiene procedures and certain dental manipulations.

Most strains of S. viridans are sensitive to penicillin, the drug of choice for the treatment of infections caused by this microorganism. However, it should be noted that Streptococcus mitis and Streptococcus sanguis require the appointment of a higher concentration of antibiotics to suppress the growth and death of microorganisms In addition, combination therapy may be necessary. This is why the identification of strains must be carried out.

Pneumonia caused by vermin streptococcus may be more common than that described above, but the certainty that vermin streptococcus isolated from blood is an etiologically significant pathogen should be based on the clinical characteristics of each patient.