Repeated isolation of a pneumococcus from a child suffering from IRAK-4 deficiency
Abstract number: p796
Dobay O., Szabó J., Borbély Á., Erdõs M., Rozgonyi F., Nagy K., Maródi L.
The IRAK-4 deficiency is a primary immunodeficiency, mainly associated with pyogenic bacterial infections like those caused by Streptococcus pneumoniae. The patients express a poor inflammatory response and fail to sustain antibody responses. In this case report we describe the repeated isolation of the same invasive pneumococcal strain from an abscess and the blood of a 5-year-old child with this disease, after a 2-year interval.
The species identity of the strains was confirmed by the optochin sensitivity and by the presence of the lytA gene. Antibiotic susceptibility testing (MIC) was performed by the agar dilution method to 10 drugs. Serotyping was done with the agglutination antisera produced by Mast Diagnostica. PFGE was performed by digestion with ApaI enzyme for 6 h at 37 °C, and the fragments separated using 2s and 30s pulse times, for 22 h at 14 °C. The presence of four macrolide resistance determinants: erm(B), mef(E/A), erm(A) and erm(TR) genes was tested by PCR.
The patient suffered from relapsing joint infections already at early age. The first invasive penumococcal infection (septic hip-joint inflammation) occurred when he was 3 years old, and it was cured with parenteral cefotaxime and non-steroid therapy. A specific anti-polysaccharide antibody deficiency was observed. The second invasive episode occurred 2 years later, when purulent meningitis followed the joint symptoms, and was cured successfully again with parenteral cefotaxime and supportive treatment. The IRAK-4 deficiency was shown at this stage and the patient received intravenous immunoglobulin substitution. The two invasive pneumococcal strains proved to be identical, by both genotyping and serotyping methods and by their antibiotic sensitivity patterns. Both strains carried the erm(B) macrolide resistance gene.
Repeated pneumococcal infections associated with IRAK-4 deficiency have been described before in the USA in 1998. However, to our knowledge, this is the first time that the isolation of the same pneumococcal strain in a patient with IRAK-4 deficiency was proven, and also confirmed by genotyping methods. In the case of pneumococci, serotyping and other phenotypic investigations are not sufficient for the determination of identical strains.
|Session name:||XXIst ISTH Congress|
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