Produção Nacional
Revisado por pares
DO VIRIDANS STREPTOCOCCI CAUSE PNEUMONIA IN CHILDREN?
2001; Lippincott Williams & Wilkins; Volume: 20; Issue: 7 Linguagem: Inglês
10.1097/00006454-200107000-00024
ISSN1532-0987
AutoresCristiana M. Nascimento‐Carvalho, Maria Cristina C. Brandileone, Maria Luiza Leopoldo Silva Guerra, José Luis Di Fábio,
Tópico(s)Infective Endocarditis Diagnosis and Management
ResumoTo The Editors: Viridans streptococci (VS) are part of normal oropharynx flora and are usually regarded as nonpathogens in pneumonia. 1 However, VS are a well-described cause of aspiration pneumonia, lung abscess, infective endocarditis, dental caries/plaque and invasive disease in immunocompromised hosts. 1 Because the pathogenesis of pneumonia in most instances involves microaspiration of virulent microorganisms that have colonized the upper respiratory tract, one would expect that VS should cause some cases of pneumonia. 2, 3 To describe the clinical characteristics of children with pneumonia from whom VS were isolated in blood culture, we reviewed the clinical records of five patients who presented to two emergency rooms in Salvador, Northeast Brazil, in a 26-month period. The diagnosis of pneumonia was based on radiologic findings. Chest radiographs were read by the duty pediatrician and were given to the mothers for follow-up purposes. Blood cultures were processed according to standard techniques and VS were recovered in pure culture. Table 1 shows the demographic and clinical findings of studied children. Table 1: Demographic and clinical findings of outpatient children with pneumonia from whom viridans streptococci were isolated in blood culturesThere were no clinical or radiographic features that would distinguish the present cases from other children with community-acquired pneumonia. 4 None had an immunosuppressive condition that would predispose to invasive VS disease. 1 There was no conclusive proof that VS were the cause of pneumonia but VS were the only organism isolated. Patients responded to antimicrobial therapy that was chosen on an empiric basis. VS are susceptible in vitro to antimicrobial agents usually prescribed for treatment of pneumonia. 1, 4–6 These bacteria may enter the blood during eating, brushing of the teeth or dental procedures without producing significant evidence of actual infection. 6 They may also contaminate blood cultures. 5, 6 Our isolated strains did not have the species identified. The majority of the strains of the VS are susceptible to penicillin, the drug of choice for treating infections with these organisms. 5 However, Streptococcus mitis and Streptococcus sanguis require higher concentrations of antibiotics for inhibition and killing than do other VS, and combination therapy may be required. 7 That is why species identification should be performed when VS are either isolated in pure culture or present as the predominant organism from a percutaneous transtracheal, pulmonary or pleural fluid aspirate and blood. 8 Resistance of these organism to penicillin does occur and usually is caused by a diminished affinity of the penicillin-binding proteins, 9 similar to the mechanism of resistance seen in Streptococcus pneumoniae. 1 To the best of the our knowledge there is only one previous report of children with pneumonia in which VS are ascribed as the etiologic agent, 10 possibly because of reluctance to accept VS as the primary pulmonary pathogen. 3, 4 It is possible that primary VS pneumonia is more common than had been previously suspected, 4–6 and clinicians must be alert to such possibility. The final decision as to the significance of blood culture isolates of VS must be made based on clinical features in the individual patient. 6 Acknowledgments. We thank Noraney N. Alves, B.Sc., Ledilce A. Athayde, B.Sc., Renilza M. Caldas, B.Sc., Maria Goreth, M. A. Barberino, B.Sc., Jussara Duarte, B.Sc. and Maria Angélica S. Brandão, B.Sc., for their technical assistance in the investigation of these cases. This study was supported by the Pan American Health Organization. Cristiana M. C. Nascimento-Carvalho, M.D. Maria Cristina C. Brandileone, Ph.D. Maria Luiza L. S. Guerra, B.Sc. José Luis Di Fabio, Ph.D.
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