RESULTS
A total of 137 patients were included in the study: 78 cases and 59
controls (Figure 1). Median age of the patients was 4.1 (1.7-7.5) years
for cases and 5.2 (2.1-9.3) for controls (p = 0.193), with a higher
percentage of males in the group of cases (78.5% vs 62.1%, p = 0.035).
The majority of the children were born in Spain and had been diagnosed
by newborn screening, while their parents were predominantly from Africa
and South/Central America. Most patients were appropriately immunized
and receiving penicillin prophylaxis, while approximately half of them
were on hydroxyurea treatment. Baseline characteristics of cases and
controls are summarized in Table 1.
Four out of 78 cases (5.1%) were diagnosed with SBI: two of them were
catheter-related bacteremia (caused by Staphylococcus aureus andEnterobacter cloacae ), one Streptococcus pneumoniae(serotype 9N) bacteremic pneumonia and one Escherichia coli UTI.
Another patient was also diagnosed with Escherichia coli UTI, but
she had a viral detection in a respiratory sample at the same time
(influenza B) and, therefore, she was considered a bacterial-viral
coinfection and excluded from the subanalyses. A virus was detected by
multiplex-PCR in 41/78 (52.6%) of the respiratory samples. The most
frequently detected virus was influenza (A or B) in 23.3% of the cases,
followed by rhinovirus in 20.9%, adenovirus in 14% and enterovirus in
11.6%. When comparing the baseline characteristics among cases with
SBI, VI and the rest of patients with NPI (Supplemental Table 1), no
statistically significant differences were found, except for the
presence of CVC and hypertransfusional regimen, which were more frequent
in the SBI group (50% vs 9.8% vs 36.4%, p = 0.011 and 50% vs 4.9%
vs 15.2%, p = 0.018, respectively).
Data on clinical presentation, laboratory parameters and outcome during
the febrile episodes in all cases, and comparisons among groups, are
summarized in Table 2. Most patients were hospitalized (81%) and
received at least one dose of empiric antibiotic treatment (96.2%).
Three patients (3.8%) required PICU admission and no patient died.
Patients with SBI had more often hemodynamic instability compared to
patients with VI or NPI (25% vs 2.4% vs 0, respectively; p = 0.012)
and significantly higher inflammatory parameters (neutrophils, CRP and
procalcitonin). They required more frequently a change in the antibiotic
therapy (75% vs 7.5% vs 15.6%; p = 0.001) and longer hospital
admissions (7.5 vs 3 vs 5 days; p = 0.013). Upper respiratory symptoms
were more frequent in patients with VI compared to patients with SBI or
NPI (80.5% vs 50% vs 42.4%, respectively; p = 0.003).