QuantiFERON-TB reversion in children and adolescents with tuberculosis.

We analyzed 136 children with tuberculosis disease or infection and a positive QuantiFERON-TB (QFT) assay, followed-up for a median of 21 months (0.4-11years). QFT reversed in 16.9% of cases, with significant decreases in TB1 (-1.72 vs. -0.03 IU/ml, p=0.001) and TB2 (-1.65 vs. -0.43 IU/ml, p=0.005) levels compared to non-reverters. We found a higher QFT reversion rate among children under 5 years (25.0% vs 11.9%, p=0.042), and those with TST induration <15mm (29% vs 13.3%, p=0.055). Our data reveal that, although QFT test remained positive in the majority of children, reversion occurred in 16% of cases in a progressive and stable pattern. Younger age and reduced TST induration were associated with QFT reversion.

The Value of the Second QuantiFERON-TB Gold-Plus Antigen Tube at Diagnosis and at Treatment Completion in Spanish Children With Tuberculosis.

We studied 295 children (tuberculosis disease, n = 159; latent tuberculosis infection, n = 136) with positive QuantiFERON-TB Gold-Plus assay results. No significant differences between first and second antigen tube interferon-gamma responses were detected, irrespective of patient and disease characteristics at diagnosis. Of patients with a repeat assay after treatment completion (n = 65), only 16.9% converted to negative results.

Host, technical, and environmental factors affecting QuantiFERON-TB Gold In-Tube performance in children below 5 years of age.

Interferon-gamma release assays performance can be impaired by host-related, technical and environmental factors, but data in young children are limited. We performed a cross-sectional study of children < 5 years-of-age at risk of tuberculosis (TB), using QuantiFERON-TB Gold In-Tube (QFT-GIT) assays. The impact of the following was evaluated: (i) host-related [age; hematological parameters; erythrocyte sedimentation rate (ESR); C-reactive protein (CRP); and tobacco smoke exposure (TSE) based on serum cotinine concentrations], (ii) technical (pre-analytical delay) and (iii) environmental factors (annual season; monthly temperatures). Of 204 children, 35 (17.2%) were diagnosed with latent TB infection or TB disease. QFT-GIT results were indeterminate in 14 (6.9%) patients. In multivariate analysis, younger age and higher ESR were associated with lower positive control responses (beta: 0.247, p = 0.002 and - 0.204, p = 0.007, respectively), and increasing age was associated with lower rates of indeterminate QFT-GIT results [OR (95% CI) 0.948 (0.903-0.996) per month, p = 0.035]. In children with positive QFT-GIT results, average monthly temperatures correlated with antigen responses (r = 0.453, p = 0.020); also, antigen responses were lower in winter than in other seasons (p = 0.027). Serum cotinine concentrations determined in a subgroup of patients (n = 41) indicated TSE in 36 (88%), positive control responses being lower in children with TSE (p = 0.034). In children < 5 years-of-age, young age, elevated ESR, temperature, annual season and TSE can affect the performance of QFT-GIT assays.

Performance of QuantiFERON-TB Gold Plus assays in children and adolescents at risk of tuberculosis: a cross-sectional multicentre study.

INTRODUCTION: The QuantiFERON-TB Gold Plus (QFT-Plus) assay, which features two antigen-stimulated tubes (TB1 and TB2) instead of a single tube used in previous-generation interferon-gamma release assays (IGRAs), was launched in 2016. Despite this, data regarding the assay's performance in the paediatric setting remain scarce. This study aimed to determine the performance of QFT-Plus in a large cohort of children and adolescents at risk of tuberculosis (TB) in a low-burden setting. METHODS: Cross-sectional, multicentre study at healthcare institutions participating in the Spanish Paediatric TB Research Network, including patients <18 years who had a QFT-Plus performed between September 2016 and June 2020. RESULTS: Of 1726 patients (52.8% male, median age: 8.4 years), 260 (15.1%) underwent testing during contact tracing, 288 (16.7%) on clinical/radiological suspicion of tuberculosis disease (TBD), 649 (37.6%) during new-entrant migrant screening and 529 (30.6%) prior to initiation of immunosuppressive treatment. Overall, the sensitivity of QFT-Plus for TBD (n=189) and for latent tuberculosis infection (LTBI, n=195) was 83.6% and 68.2%, respectively. The agreement between QFT-Plus TB1 and TB2 antigen tubes was excellent (98.9%, κ=0.961). Only five (2.5%) patients with TBD had discordance between TB1 and TB2 results (TB1+/TB2-, n=2; TB1-/TB2+, n=3). Indeterminate assay results (n=54, 3.1%) were associated with young age, lymphopenia and elevated C reactive protein concentrations. CONCLUSIONS: Our non-comparative study indicates that QFT-Plus does not have greater sensitivity than previous-generation IGRAs in children in both TBD and LTBI. In TBD, the addition of the second antigen tube, TB2, does not enhance the assay's performance substantially.

QuantiFERON-TB Gold Plus Assay Specificity in Children and Adolescents With Suspected Tuberculosis-A Multicenter Cross-sectional Study in Spain.

In this cross-sectional study of 284 children and adolescents with clinically or radiologically suspected tuberculosis in a low-endemic country, the QuantiFERON-TB Gold Plus assay specificity, sensitivity, positive predictive value and negative predictive value were 91.5%, 87.3%, 86.4%, and 91.2%, respectively. The specificity was higher than that observed in tuberculin skin tests performed simultaneously, but similar to previous-generation interferon-gamma release assays.

Effects of a Paediatric Antimicrobial Stewardship Program on Antimicrobial Use and Quality of Prescriptions in Patients with Appendix-Related Intraabdominal Infections.

The effectiveness of antimicrobial stewardship programs (ASP) in reducing antimicrobial use (AU) in children has been proved. Many interventions have been described suitable for different institution sizes, priorities, and patients, with surgical wards being one of the areas that may benefit the most. We aimed to describe the results on AU and length of stay (LOS) in a pre-post study during the three years before (2014-2016) and the three years after (2017-2019) implementation of an ASP based on postprescription review with feedback in children and adolescents admitted for appendix-related intraabdominal infections (AR-IAI) in a European Referral Paediatric University Hospital. In the postintervention period, the quality of prescriptions (QP) was also evaluated. Overall, 2021 AR-IAIs admissions were included. Global AU, measured both as days of therapy/100 patient days (DOT/100PD) and length of therapy (LOT), and global LOS remained unchanged in the postintervention period. Phlegmonous appendicitis LOS (p = 0.003) and LOT (p < 0.001) significantly decreased, but not those of other AR-IAI diagnoses. The use of piperacillin-tazobactam decreased by 96% (p = 0.044), with no rebound in the use of other Gram-negative broad-spectrum antimicrobials. A quasisignificant (p = 0.052) increase in QP was observed upon ASP implementation. Readmission and case fatality rates remained stable. ASP interventions were safe, and they reduced LOS and LOT of phlegmonous appendicitis and the use of selected broad-spectrum antimicrobials, while increasing QP in children with AR-IAI.

Benefits of a Pediatric Antimicrobial Stewardship Program in Antimicrobial Use and Quality of Prescriptions in a Referral Children's Hospital.

OBJECTIVES: To evaluate the results of the first 24 months of a postprescription review with feedback-based antimicrobial stewardship program in a European referral children's hospital. STUDY DESIGN: We performed a pre-post study comparing antimicrobial use between the control (2015-2016) and the intervention periods (2017-2018) expressed in days of therapy/100 days present. Quality of prescriptions was evaluated by quarterly cross-sectional point-prevalence surveys. Length of stay, readmission rates, in-hospital mortality rates, cost of systemic antimicrobial agents, and antimicrobial resistance rates were included as complementary outcomes. RESULTS: Total antimicrobial use and antibacterial use significantly decreased during the intervention period (P = .002 and P = .001 respectively), and total antifungal use remained stable. A significant decline in parenteral antimicrobial use was also observed (P < .001). In 8 quarterly point-prevalence surveys (938 prescriptions evaluated), the mean prevalence of use of any antimicrobial among inpatients was 39%. An increasing trend in the rate of optimal prescriptions was observed after the first point-prevalence survey (P = .0898). Nonoptimal prescriptions were more common in surgical than in medical departments, in antibacterial prescriptions with prophylactic intention, and in empirical more than in targeted treatments. No significant differences were observed in terms of mortality or readmission rates. Only minor changes in antimicrobial resistance rates were noted. CONCLUSIONS: Our antimicrobial stewardship program safely decreased antimicrobial use and expenditure, and a trend toward improvement in quality of prescription was also observed.

Diagnostic Accuracy of QuantiFERON-TB Gold Plus Assays in Children and Adolescents with Tuberculosis Disease.

In 2016, a new interferon-gamma release assay, QuantiFERON-TB Gold Plus, was introduced. We conducted a cross-sectional multicenter study, involving 158 children and adolescents with tuberculosis disease. The overall sensitivity of the assay was 82.9% (IQR 77.0%-88.8%), indicating that in children this test does not have higher sensitivity than previous generation interferon-gamma release assays.

Impact of Baseline Tuberculin Skin Test and Isoniazid Chemoprophylaxis on Subsequent Quantiferon-TB Gold In-Tube Performance in Young Children Assessed After Tuberculosis Contact in Catalonia.

We investigated the impact of baseline tuberculin skin tests (TSTs) and preventive isoniazid chemoprophylaxis on subsequent QuantiFERON-TB Gold In-Tube (QFT-GIT) assays performed after a 10- to 12-week window period in 114 children <5 years of age. Previous TSTs and chemoprophylaxis had no impact on the magnitude of subsequent antigen-induced responses in QFT-GIT. Furthermore, previous TSTs did not induce conversion from a negative to a positive QFT-GIT result.

Osteoarticular infections: Blood as a determinant factor in the isolation of Kingella kingae.

We assessed the capacity of Kingella kingae to grow in blood culture bottles (BCB), taking into account the concentrations of the microorganism and blood in the culture medium. An initial suspension (McFarland 0.5) of 32 strains of K. kingae was serially diluted. One mL of the initial suspension and 1 mL of the subsequent dilutions were inoculated in two BCB, together with 1 mL of human blood in the 2nd BCB. Also, 1mL serial dilutions of human blood were added to BCBs previously inoculated with 1 mL of K. kingae dilution 1/104. In non-blood-supplemented BCB, 23 strains grew with the initial suspension and only one with the first processed dilution, as compared to all strains with the initial suspension and the 3 first dilutions, 22 with the 4th dilution, and one with the 5th dilution in blood-supplemented BCB. In BCB inoculated with K. kingae dilution 1/104 and decreasing concentrations of human blood, all strains grew with blood dilutions 1/2 and 1/4, 26 with dilution 1/8, 19 with dilution 1/16, 10 with dilution 1/32, and none with dilution 1/64. Increasing time to positivity was observed with both decreasing bacterial (p = .001) and blood concentrations (r = -0.632, p < .0001). The addition of human blood was essential to boost the growth of K. kingae in BCB. If replicated in vivo, these findings would increase the isolation of fastidious K. kingae organisms from pediatric osteoarticular exudates.

Performance of Tuberculin Skin Tests and Interferon-γ Release Assays in Children Younger Than 5 Years.

BACKGROUND: Available data to assess the optimal diagnostic approach in infants and preschool children at risk of tuberculosis (TB) are limited. METHODS: We conducted a prospective observational study in children younger than 5 years undergoing assessment with both tuberculin skin tests (TST) and QuantiFERON-TB Gold In-Tube (QFT-GIT) assays at 2 tertiary TB units in Barcelona, Spain. RESULTS: A total of 383 children were included. One of 304 participants considered uninfected developed active TB during follow-up {median [interquartile range (IQR)]: 47 [30; 48] months}, compared with none of 40 participants with latent TB infection [follow-up since completion of anti-TB treatment: 42 (32; 45) months]. Overall test agreement between TST and QFT-GIT was moderate (κ = 0.551), but very good in children screened after TB contact (κ = 0.801) and in Bacillus Calmette-Guérin (BCG)-unvaccinated children (κ = 0.816). Discordant results (16.8%, all TST+/QFT-GIT-) were mainly observed in new-entrant screening and in BCG-vaccinated children. Children with indeterminate QFT-GIT results were on average younger than those with determinate results (median age: 12 vs. 30 months; P < 0.001). The sensitivity of TSTs and QFT-GIT assays in children with confirmed active TB was 100% (95% confidence interval: 79.4%-100%) and 93.7% (95% confidence interval: 69.8%-99.8%), respectively. In patients with latent TB infection or active TB, there was no correlation between age and antigen-stimulated interferon-γ responses (r = -0.044; P = 0.714). CONCLUSIONS: In young BCG-unvaccinated children with recent TB contact, a dual testing strategy using TST and QFT-GIT in parallel may not be necessary. However, TST+/QFT-GIT- discordance is common, and it remains uncertain if this constellation indicates TB infection or not. In active TB, QFT-GIT assays do not perform better than TSTs.

Demodicosis in two patients with a previous history of Langerhans cell histiocytosis.

Demodex mites are commensal organisms rarely found in healthy children. Human demodicosis can be classified as a primary or a secondary form. The secondary form in children usually affects severely immunodepressed children. To our knowledge, this is the first report of human demodicosis associated with Langerhans cell histiocytosis. These cases show that this skin disorder can occur months after completing chemotherapy, without recurrence of the systemic disease.

Detection of Streptococcus pneumoniae and Haemophilus influenzae type B by real-time PCR from dried blood spot samples among children with pneumonia: a useful approach for developing countries.

BACKGROUND: Dried blood spot (DBS) is a reliable blood collection method for storing samples at room temperature and easily transporting them. We have previously validated a Real-Time PCR for detection of Streptococcus pneumoniae in DBS. The objective of this study was to apply this methodology for the diagnosis of S. pneumoniae and Haemophilus influenzae b (Hib) in DBS samples of children with pneumonia admitted to two hospitals in Mozambique and Morocco. METHODS: Ply and wzg genes of S. pneumoniae and bexA gene of Hib, were used as targets of Real-Time PCR. 329 DBS samples of children hospitalized with clinical diagnosis of pneumonia were tested. RESULTS: Real-Time PCR in DBS allowed for a significant increase in microbiological diagnosis of S. pneumoniae and Hib. When performing blood bacterial culture, only ten isolates of S. pneumoniae and none of Hib were detected (3·0% positivity rate, IC95% 1·4-5·5%). Real-Time PCR from DBS samples increased the detection yield by 4x fold, as 30 S. pneumoniae and 11 Hib cases were detected (12·4% positivity rate, IC95% 9·0-16·5%; P<0·001). CONCLUSION: Real-Time PCR applied in DBS may be a valuable tool for improving diagnosis and surveillance of pneumonia caused by S. pneumoniae or Hib in developing countries.

Pneumococcal serotypes causing acute otitis media among children in Barcelona (1992-2011): emergence of the multiresistant clone ST320 of serotype 19A.

BACKGROUND: There is scarce information about changes in serotypes and clonal types of Streptococcus pneumoniae causing acute otitis media (AOM) in recent years, particularly in European countries. METHODS: Pneumococcal serotypes and clones from S. pneumoniae strains isolated from children with AOM who were attended at Hospital Sant Joan de Déu, Barcelona (1992 to 2011), were studied. Heptavalent pneumococcal conjugate vaccine (PCV7) was introduced in June 2001. We defined 3 periods: prevaccine period 1992 to 2001, early vaccine period 2002 to 2006 and late vaccine period 2007 to 2011. RESULTS: There were 376 pneumococcal strains causing AOM, and 373 (99.2%) of them were serotyped. AOM caused by PCV7 serotypes declined significantly: 161 of 245 (65.7%) episodes in 1992 to 2001 versus 22 of 67 (32.8%) in 2002 to 2006 versus 8 of 61 (13.1%) in 2007 to 2011 P < 0.001. In the last period (2007 to 2011), the potential serotype coverage for the PCV10 was 16.4% and for the PCV13 was 68.9% (P < 0.001). Serotype 19A increased from 5.7% in 1992 to 2001 to 42.6% in 2007 to 2011 (P < 0.001). Among strains with penicillin minimal inhibitory concentration ≥0.12 µg/mL (n = 241), serotype 19A rose from 2.3% in the first period to 57.9 % in the last period (P < 0.001). The clonal-type ST320 was initially detected in 2005, and in the period 2007 to 2011, the ST320 was found in 72.7% of nonsusceptible serotype 19A isolates. CONCLUSIONS: Among children with AOM, a rapid expansion of the multiresistant clone ST320 expressing serotype 19A has been observed in Barcelona. The implementation of PCV13, which includes this serotype, may decrease the prevalence of AOM and reduce antimicrobial resistance.