Nachweis bakterieller Superinfektionen bei Patienten mit Influenza A H1N1 mithilfe kultur-unabhängiger molekulargenetischer Typisierung

Abstract

Diagnosis of bacterial superinfections of patients with influenza A H1N1 by culture-independent DNA sequence typing. During the current influenza A H1N1 pandemia the clinical course in infancy and childhood is generally mild and the frequency of hospitalization is low. However, pulmonary infections can be aggravated by bacterial superinfections in the absence of early and appropriate antibiotic treatment. Super-infections are mainly caused by Streptococcus. pneumoniae, Streptococcus pyogenes and Staphylococcus aureus. A complicated respiratory infection of an eight year old boy with influenza A H1N1 infection prompted us to review the clinical role of bacterial super-infections with consequences for prevention, antibiotic treatment and application of new diagnostic culture-independent techniques. The patient was admitted to a tertiary care hospital due to clinical signs and symptoms of pneumonia. X-ray analysis demonstrated opacity of the right lung with concomitant pleural effusions. Antibiotic therapy was initiated with erythromycin and cefuroxim i.v.; however, without clinical success. Following transfer to the University Childrens Hospital of Saarland Influenza A H1N1 infection was diagnosed by PCR in a respiratory swab. Oseltamivir treatment was initiated and the antibiotic therapy for bacterial superinfections was changed to meropenem. In parallel, the pleural effusions were drained. Classical bacterial and fungal cultures from pleural effusions remained sterile whereas the panbacterial PCR using universal 16S RNA primer was positive. Consecutively, S. pneumoniae genome was identified by culture-independent sequence typing in pleural effusions and later on also in abscess material. Antibiotic therapy was changed for additional two weeks using penicillin G. Following thoracic surgery with debridement and drainage of two independent pulmonary abscesses the patient was discharged without further treatment. Conclusions: Bacterial post-influenza A superinfections require early antibiotic therapy with activity against both, streptococcal and staphylococcal infections. Following antibiotic pre-treatment the causing pathogen of superinfections can still be identified by culture-independent molecular-genetic methods even in otherwise sterile samples. Pneumococcal vaccination may help to prevent a significant proportion of severe respiratory infections following influenza.