Microbiological evaluation from extracted tonsils and swab tonsils from all cases.

<p>Microbiological evaluation from extracted tonsils and swab tonsils from all cases.</p

The carriage of interleukin-1B-31*C allele plus <i>Staphylococcus aureus</i> and <i>Haemophilus influenzae</i> increases the risk of recurrent tonsillitis in a Mexican population

<div><p>The aim of the present study was to estimate the relative contribution of immunogenetic and microbiological factors in the development of recurrent tonsillitis in a Mexican population. Patients (n = 138) with recurrent tonsillitis and an indication of tonsillectomy (mean age: 6.05 years ± 3.00; median age: 5 years, female: 58; age range: 1–15 years) and 195 non-related controls older than 18 years and a medical history free of recurrent tonsillitis were included. To evaluate the microbial contribution, tonsil swab samples from both groups and extracted tonsil samples from cases were cultured. Biofilm production of isolated bacteria was measured. To assess the immunogenetic component, DNA from peripheral blood was genotyped for the <i>TNFA-308G/A</i> single-nucleotide polymorphism (SNP) and for the <i>IL1B -31C/T</i> SNP. Normal microbiota, but no pathogens or potential pathogens, were identified from all control sample cultures. The most frequent pathogenic species detected in tonsils from cases were <i>Staphylococcus aureus</i> (48.6%, 67/138) and <i>Haemophilus influenzae</i> (31.9%, 44/138), which were found more frequently in patient samples than in samples from healthy volunteers (<i>P</i> < 0.0001). Importantly, 41/54 (75.9%) <i>S</i>. <i>aureus</i> isolates were biofilm producers (18 weak and 23 strong), whereas 17/25 (68%) <i>H</i>. <i>influenzae</i> isolates were biofilm producers (10 weak, and 7 strong biofilm producers). Patients with at least one copy of the <i>IL1B-31*C</i> allele had a higher risk of recurrent tonsillitis (OR = 4.03; 95% CI = 1.27–14.27; <i>P</i> = 0.013). <i>TNFA-308 G/A</i> alleles were not preferentially distributed among the groups. When considering the presence of <i>IL1B-31*C</i> plus <i>S</i>. <i>aureus</i>, <i>IL1B-31*C</i> plus <i>S</i>. <i>aureus</i> biofilm producer, <i>IL1B-31*C</i> plus <i>H</i>. <i>influenzae</i> or <i>IL1B-31*C</i> plus <i>H</i>. <i>influenzae</i> biofilm producer, the OR tended to infinite. Thus, the presence of <i>IL1B-31*C</i> allele plus the presence of <i>S</i>. <i>aureus</i> and/or <i>H</i>. <i>influenzae</i> could be related to the development of tonsillitis in this particular Mexican population.</p></div

Genotype and allele frequencies of <i>TNFA-308G/A</i> and <i>IL1B-31C/T</i> in recurrent tonsillitis and control patients.

<p>Genotype and allele frequencies of <i>TNFA-308G/A</i> and <i>IL1B-31C/T</i> in recurrent tonsillitis and control patients.</p

Odds ratios (OR) with 95% confidence intervals (CIs) for risk factors.

<p>Odds ratios (OR) with 95% confidence intervals (CIs) for risk factors.</p