Specific antibody deficiency with normal immunoglobulin concentration in children with recurrent respiratory infections

BACKGROUND: Response to polysaccharide antigens is a test to evaluate the immunological competence of children with recurrent respiratory infections (RRI) of unknown cause and no other immune system abnormality. In order to detect specific antibody deficiency (SAD), a group of children with RRI without other immunodeficiency were prospectively studied. METHODS: We included 20 children (12 male), age range 3-14 years, with six or more annual episodes of respiratory infections (RI); one or more monthly episodes of RI during the winter months; or three or more annual episodes of lower RI. The children were immunised with 23-valent polysaccharide anti-pneumococcal vaccine, and ELISA was used to measure anti-polysaccharide IgG antibody levels for 10 pneumococcal serotypes at baseline (T0), and 45 days (T1) and one year post-immunisation (T2). Post-immunisation response above 1.3 μg/ml for more than 50% of the serotypes was considered normal for children 2-5 years, and for more than 70% of the serotypes in children older than 5 years. RESULTS: At T1 19/20 children showed a normal response for their age, and only one patient showed a deficient response, suggestive of classic moderate SAD. At T2, 8/20 patients showed deficient responses, suggestive of impaired persistence of specific antibodies. There was a noteworthy association between deficient response and asthma and allergic rhinitis. CONCLUSIONS: We propose first ruling out local or systemic causes, then performing serum immunoglobulin IgM, IgG, IgA, IgE and IgG

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Caracterización de Escherichia coli de los grupos filogenéticos A y B1 causantes de infección extraintestinal / Characterization of Escherichia coli isolates derived from phylogenetic groups A and B1 causing extraintestinal infection

Introducción. Escherichia coli de los grupos filogenéticos no patógenos A y B1 raramente causan infecciones extraintestinales. El objetivo de este estudio es el de caracterizar 37 E. coli de los grupos filogenéticos A y B1 y compararlos con 37 E. coli del grupo B2 y 31 del grupo D, productores de las mismas infecciones. Métodos. De estos 105 casos de E. coli aislados de orina de pacientes con cistitis y pielonefritis y de sangre de pacientes con sepsis urinaria y de otros orígenes, se estudió el grupo filogenético, 15 genes de virulencia, los antígenos O asociados a infección extraintestinal y la sensibilidad a fluoroquinolonas. Resultados. Los aislados de E. coli de los grupos A/B1 presentaron menos determinantes de virulencia (media de 3,5) que los del grupo B2 (8,6; p < 0,001) y D (5,3; p < 0,001); sin embargo un subgrupo formado por 3 aislados del grupo A y 5 del B1 poseían 5 o más factores. E. coli de los grupos A/B1 se asociaron con frecuencia significativa a resistencia a fluoroquinolonas (74%; p < 0,001), mientras que los del grupo B2 se asociaron a sensibilidad (76%; p 5 0,003). E. coli de los grupos A/B1 se aislaron de forma significativa en pacientes con pielonefritis y sepsis y factores favorecedores de infección, asociación que no se observó en pacientes con cistitis. Conclusión. E. coli de los grupos filogenéticos A y B1, a pesar de que en general presentan un bajo potencial patógeno, se han mostrado capaces de producir infecciones extraintestinales, especialmente en pacientes con factores favorecedores de infección (AU)

Introduction. Escherichia coli isolates from the non-pathogenic phylogenetic groups A and B1 rarely cause extraintestinal infections. The aim of this study was to analyze 37 E. coli isolates pertaining to phylogenetic groups A and B1 and compare them with 37 E. coli isolates from group B2 and 31 from group D, which caused the same infections. Methods. Among 105 E. coli isolated from the urine of patients with cystitis and pyelonephritis and from the blood of patients with urinary-source and other-source bacteriemia, the E. coli phylogenetic groups, 15 virulence-associated genes, 7 O-antigens and fluoroquinolone resistance were analyzed. Results. E. coli from groups A and B1 showed fewer virulence determinants (median 3.5) than E. coli from group B2 (8.6, P < .001) or D (5.3, P < .001); however, a subgroup containing 3 isolates from group A and 5 from B1 harbored 5 o more factors. E. coli from groups A/B1 were associated with resistance to fluoroquinolones (74%, P < .001), whereas E. coli from group B2 were associated with susceptibility to this antibiotic (76%, P 5 .003). E. coli from groups A/B1 were isolated significantly more frequently in patients with pyelonephritis or sepsis and local or general factors favoring infection, association not observed in patients with cystitis. Conclusions. Even though most of the E. coli isolates from phylogenetic groups A and B1 presented a low virulence potential, they were able to cause extraintestinal infections, particularly in compromised patients (AU)