BV score differentiates viral from bacterial-viral co-infection in adenovirus PCR positive children

Background and objectives Adenovirus causes acute respiratory illness that can mimic bacterial infection, making it challenging to differentiate adenoviral infection from adenoviral-bacterial co-infection. A host-protein score (BV score) for differentiating bacterial from viral infection that combines the expression levels of TNF-related apoptosis-induced ligand, interferon gamma-induced protein-10, and C-reactive protein exhibited a negative predictive value (NPV) of 98% in prior studies. Here we evaluate BV score's diagnostic accuracy in pediatrics with adenovirus PCR detection. Methods This is a sub-analysis of children aged 3 months to 20 years with adenovirus PCR-positive infection recruited prospectively in two previous cohort studies. Reference standard diagnosis (bacterial, viral or indeterminate) was based on expert adjudication. BV score ranges from 0 to 100 and provides three results based on predefined cutoffs: viral or other non-bacterial etiology (0 ≤ score < 35), equivocal (35 ≤ score ≤ 65), and bacterial or co-infection (65 < score ≤ 100). Experts were blinded to BV results. Results Out of 1,779 children, 142 had an adenovirus PCR-positive nasopharyngeal swab. Median age was 1.2 years (interquartile range 0.6–1.8), 50.7% were male and 52.8% were hospitalized. 12 cases were reference standard bacterial, 115 reference standard viral and 15 were indeterminate. BV score attained sensitivity of 100.0% (no false negatives), specificity of 89.5% (95% confidence interval: 83.2–95.8), and NPV of 100.0% (92.6–100.0). Equivocal rate was 19.7%. Conclusions BV score accurately differentiated between adenoviral and bacterial-adenoviral co-infection in this cohort of children with PCR-positive adenovirus detection. This performance supports a potential to improve appropriate antibiotic use.


Eligibility criteria employed in the original studies
CURIOSITY [1] Inclusion criteria: clinical suspicion of an acute infectious disease, peak fever >37.5°C since onset of symptoms, and duration of symptoms ≤12 days.
Exclusion criteria: evidence of acute infection in the two weeks preceding enrollment; congenital immune deficiency; treatment with immunosuppressive or immunomodulatory therapy; active malignancy; and human immunodeficiency virus (HIV), or hepatitis B/C virus infection.

OPPORTUNITY [2]
Inclusion criteria: patients aged between 2 and 60 months presenting with fever (peak temperature ≥38.0°C measured by axillary, rectal, or ear thermometer) and symptoms of lower respiratory tract infection or fever without source existing for a maximum of 6 days.
Exclusion criteria: previous episode of fever in the past 3 weeks; psychomotor retardation; moderate to severe metabolic disorder; primary or secondary immunodeficiency; HIV, infection by hepatitis B or hepatitis C viruses; and active malignancies.

Laboratory procedures
In the CURIOSITY study, nasal swabs were stored at 4°C for up to 72h before transport to a central laboratory, where two multiplex PCR analyses were conducted to detect common respiratory viral (Seeplex RV15) and bacterial (Seeplex PB6) pathogens. Venous blood specimens were stored at 4°C for up to 5h before fractionation into serum and plasma and storage at −80°C. Host-protein biomarkers were measured as follows: CRP using either Cobas-6000, Cobas-Integra-400/800, or Modular-Analytics-P800 (Roche); TRAIL and IP-10 using ImmunoXpert™ (MeMed).
In the OPPORTUNITY study, nasal swabs were collected (universal transport medium, Copan, Brescia, Italy), frozen within 2h and stored at -80°C before transport to the MeMed laboratory, where multiplex PCR testing was performed for 15 common respiratory viruses (Seeplex RV15, Seegene, Seoul, South Korea). Similarly, venous blood specimens were fractionated into serum and plasma within 2h of collection and stored at −80°C before transport to the MeMed laboratory; TRAIL and IP-10 measurements were performed using ImmunoXpert™ (MeMed) and CRP was measured using Cobas e501 or Cobas-6000.

Statistical analysis
Sensitivity was defined as the number of patients that received a bacterial reference standard and a bacterial BV score (score>65), divided by the number of patients that received a bacterial reference standard. Specificity was symmetrically defined as the number of patients that received a viral reference standard and a viral BV score (score<35), divided by the number of patients that received a viral reference standard. The percentage of cases assigned an equivocal score (35≤score≤65) was reported. Fisher's exact test was used for comparing proportions.
Positive predictive value (PPV) was defined as the number of patients that received a bacterial reference standard and a bacterial index test score (score > 65), divided by the number of patients that received a bacterial index test score. Negative predictive value (NPV) was symmetrically defined as the number of patients that received a viral reference standard and a viral index test score (score < 35), divided by the number of patients that received a viral index test score. Fever, vomiting and diarrhea, 4 days before admission contacted ED, was diagnosed as viral GE, treated with fluids and discharged home. Returned to the ED because of no improvement. known background of congenital hypothyroidism. In physical examination: conjunctivitis. Admitted and treated with fluids, improvement after treatment.