Agathe de Lauzanne

Real-Time PCR Measurement of Persistence of Bordetella pertussis DNA in Nasopharyngeal Secretions during Antibiotic Treatment of Young Children with Pertussis

ABSTRACT We used real-time PCR to examine the persistence of Bordetella pertussis DNA in serial nasopharyngeal aspirates from 22 children treated for pertussis. After 5 days of treatment, PCR was positive for all 21 assessable patients. After 14 and 21 days, PCR was still positive for 83% (10/12) and 66% (4/6) of assessable patients, respectively. One patient was tested 1 month after treatment initiation, and B. pertussis DNA was still detectable. Quantitative analysis showed that the DNA concentration diminished during treatment in all except one case. The PCR cycle threshold at which B. pertussis DNA became detectable increased by a mean of 1.7 cycles per day (range, 0.86 to 3.68 cycles per day). Real-time PCR can thus be used to diagnose pertussis in young children for up to 3 weeks after treatment initiation. Its potential value for assessing the treatment outcome remains to be determined.

Interferon-gamma release assay performance for diagnosing tuberculosis disease in 0- to 5-year-old children.

QuantiFERON-TB Gold In-Tube performance was evaluated in 19 French immunocompetent children (0.29–5.36 years; median: 1.52) with active tuberculosis. The rate of indeterminates results was 0/19 and the rates of positivity were 6/10 and 9/9 in <2 and 2- to 5-year-old children, respectively. QuantiFERON-TB Gold In-Tube in association with tuberculin skin test could improve diagnosis of tuberculosis even in young children.

QuantiFERON to diagnose infection by Mycobacterium tuberculosis: Performance in infants and older children

OBJECTIVES QuantiFERON value to diagnose tuberculosis (TB) in young children remains to be clarified. To this aim QF-TB-IT performance was evaluated in a large series of immunocompetent children that were stratified according to age and clinical conditions. METHODS QF-TB-IT reactivity was analyzed in 226 immunocompetent children (0-15 years old): 31 were uninfected despite TB contact; 51 presented TB disease; 39 had Latent TB (LTBI) and 105 had TB disease suspected but an alternative diagnosis (TB excluded). RESULTS QF-TB-IT specificity was 100% in TB excluded. In TB disease, low sensitivity of QF-TB-IT in infants (40%) increased with aging (77% in 1-<5 years and 82% in 5-<15 years old subgroups). In LTBI, agreement between TST and QF-TB-IT was 0% in infants, 40% in 1-<5 years and 57% in children >5 years old. Finally, the incidence of indeterminate results was high (24%) in children <5 years old with TB excluded, especially with non-TB pneumonitis (61%), but was low (0-6%) regardless of age group in TB disease, LTBI and uninfected contact cases. CONCLUSIONS In our low burden country, i) QF-TB-IT specificity was 100%, ii) QF-TB-IT sensitivity was low in infants but commensurable to adult values in older children, and iii) indeterminate results mostly relied on ongoing infections unrelated to TB.

TNF-α/IL-2 ratio discriminates latent from active tuberculosis in immunocompetent children: a pilot study.

Background:Distinguishing latent tuberculosis (LTB) from tuberculosis (TB) disease may be challenging in children. Here, we analyzed cytokine profiles that can distinguish the two infection stages in a nonendemic country (France).Methods:Immunocompetent children with LTB (n = 6) or TB disease (n = 8) (median age: 6.2 and 5.7 years, respectively) were analyzed. Four young uninfected children were included as controls. A Luminex assay evaluated cytokine responses to Mycobacterium tuberculosis antigens.Results:Poor interleukin-4 (IL-4) and IL-10 responses precluded analysis of these cytokines. Interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), IL-2, and T-helper type 1 (Th1) cytokines and IL-5, IL-13, T-helper type 2 (Th2) cytokines were simultaneously induced by antigens in 14/14 infected but 0/4 uninfected children. Th1 cytokine levels were similar in LTB and TB disease: IFN-γ: 12,254 and 10,495 pg/ml; IL-2: 2,097 and 1,869 pg/ml; and TNF-α: 1,020 and 2,875 pg/ml, respectively. Th2 cytokine levels were similar and even higher in LTB than in TB disease: IL-5: 23 and 10 pg/ml; IL-13: 284 and 109 pg/ml, respectively. Positive correlation of cytokine levels, whether Th1 or Th2, was observed. Higher (P = 0.008) TNF-α/IL-2 ratios distinguished 6/8 active TB disease cases from 6/6 LTB cases.Conclusion:TNF-α/IL-2 ratio may discriminate TB disease from LTB in immunocompetent children. Larger studies in TB endemic settings must verify these results.

Aetiology and epidemiology of fever in children presenting to the emergency department of a French paediatric tertiary care centre after international travel

Objective As few data are available on the causes of fever in children returning from international travel, the authors studied children presenting to a French tertiary care centre with fever. Methods Children presenting to the emergency department of the Robert Debré Paediatric Hospital, Paris, France between July and December 2007 with fever that occurred within 3 months of a stay abroad were included in this retrospective study. Results The children (n=538) had most commonly visited North Africa (NA) (n=214), sub-Saharan Africa (SSA) (n=185) and Europe (n=67). Their median age was 2.8 years (IQR 1.4–5.8). The median time between their return to France and the onset of fever was 5 days (IQR 0–18). Cosmopolitan infections represented 85% of the established diagnoses (97.8% and 63.9% in the children returning from NA and SSA, respectively). Fever of unknown origin accounted for 19.3% of cases. Malaria was the leading tropical infection. Excluding malaria, diarrhoeal diseases were more frequent in the children returning from NA (38.5%) than in those returning from SSA (24.5%). Malaria was associated with stays in endemic countries that exceeded 30 days (OR 3.13, 95% CI 1.02 to 9.59). Conclusion Cosmopolitan infections are the leading cause of fever in French children returning from tropical and subtropical areas. However, all febrile children who have returned from an endemic area should be tested for malaria.

Ethambutol-related impaired visual function in childrens less than 5 years of age treated for a mycobacterial infection: diagnosis and evolution.

Background: The effects of ethambutol (EMB) on vision are particularly difficult to detect in children less than 5 years of age because of a lack of complaints and objective clinical signs. The aim of this study was to assess the frequency of visual abnormalities and the utility of visual-evoked potentials (VEPs) recordings in monitoring the visual function of children less than 5 years of age who were exposed to EMB during anti-mycobacterial treatment. Methods: We performed a retrospective study in Robert-Debré University Hospital, Paris, France, including all children less than 5 years of age, who were treated with EMB for a mycobacterial infection from January 2002 to December 2012. Results: Fourteen patients were enrolled, including 12 treated for Mycobacterium tuberculosis infection. The sex ratio was 1:1. The median age was 1.65 years (0.3 to 4.7). Five patients had subarachnoid involvement. The median EMB dose was 22 mg/kg/day (15 to 27). Only 11 patients were monitored using VEPs. Three children (27.3%) developed a visual impairment secondary to EMB, with delays of 4, 7 and 36 weeks. One of the 3 patients developed an impairment of the retrochiasmatic visual pathways, and 2 other patients developed classical retrobulbar optic neuritis. In all cases, the discontinuation of EMB resulted in a normalization of these findings. Conclusion: Alterations in visual function related to the use of EMB are not uncommon in young children and are most likely underestimated. Systematic close monitoring using VEPs recordings is needed in young children treated with EMB.

Altered cytokine profiles in children with indeterminate quantiferon results and common infections

OBJECTIVES An increased rate of indeterminate quantiferon results (low IFN-γ release in the phytohemagglutinin-stimulated tube) has been reported in children with clinical signs compatible with tuberculosis but with the final diagnosis of infectious diseases different from tuberculosis. Here, we addressed the mechanisms involved and assessed potential alternative biomarkers to overcome indeterminate quantiferon results under these conditions. METHODS Cytokine concentrations were measured in residual plasma from quantiferon assays performed in immunocompetent children (cases, median age: 3 years 9 months) with indeterminate results and community acquired pneumonia (n = 7) or meningoencephalitis (n = 1). Controls were age-matched immunocompetent children with determinate quantiferon results (infected with mycobacterium tuberculosis, n = 7 or not, n = 8). RESULTS Lower IFN-γ expression in phytohemagglutinin-stimulated cultures from cases was accompanied by lower Th1 (IL-2, TNF-α, IP-10) and Th2 (IL-5, IL-13), but similar IL-10 secretion capacities as the controls. CONCLUSIONS A state of hyporesponsiveness that resembles the concept of immunoparalysis in severe infection was observed in children with milder infections. Though IP-10, IL-2, IL-5 and IL-13 were confirmed as promising alternative biomarkers for discriminating controls with and without tuberculosis in this study, defective induction of these biomarkers by phytohemagglutinin in cases precluded their usefulness in overcoming quantiferon indeterminate results in the above-mentioned clinical conditions.

Enteric fever among children: 50 cases in a French tertiary care centre

Background Enteric fever in France is primarily travel-associated. Characteristics of paediatric cases are scarce and information from field studies in endemic countries might not be generalizable to non-endemic countries. Methods In this retrospective study, we reviewed all cases of typhoid and paratyphoid fever treated in a French paediatric tertiary care centre from 1993 to 2015. Results Fifty cases of enteric fever due to Salmonella enterica serovar Typhi (n = 44) and Paratyphi (n = 6) were identified. Sixty-one percent of the children had travelled to Africa and 34% to the Indian subcontinent. Among travel-associated cases, 85% were visiting friends and relatives (VFR). Ninety-six percent had high fever associated with gastrointestinal symptoms. Anaemia (66%), elevated C-reactive protein (80%), transaminitis (87%) and mild hyponatremia (50%) were the main biological findings. Blood cultures were positive in 90% of cases. Twelve strains (24%) were resistant at least to one antibiotic, and all of them had been isolated since 2003, increasing the resistance rate during this last period to 43% (12/28). Ceftriaxone was administered to 71 patients for a median duration of 6 days (interquartile range (IQR): 4-8). The median time to apyrexia after the onset of treatment was 4 days (IQR: 2-5 days). Complications occurred in nine children with five (10%) presenting neurologic disorders. All 50 patients recovered. Conclusion In France, paediatric enteric fever is mainly a travel-associated disease and occurs in patients returning from a prolonged stay in an endemic area. Children VFR are at high risk and should be a priority target group for pre-travel preventive measures. The increase in antibiotic resistance reflects the situation in endemic countries and is a major concern.

RANDOMIZED STUDY OF THE EFFECT OF TOPICAL ANESTHESIA ON TUBERCULIN SKIN TEST REACTION SIZE IN CHILDREN

Tuberculin skin test (TST) application in children can be eased by topical anesthesia, but no study has determined whether lidocaine-prilocaine mixture application modifies TST skin reactions. We compared TST performed with and without topical anesthesia in 46 children (range, 0.4–15.9 years), and found that topical lidocaine-prilocaine did not affect the TST size reaction. Topical lidocaine-prilocaine can be used for TST.