Humoral immunity to SARS-CoV-2 and seasonal coronaviruses in children and adults in north-eastern France.

BACKGROUND: Children are underrepresented in the COVID-19 pandemic and often experience milder disease than adolescents and adults. Reduced severity is possibly due to recent and more frequent seasonal human coronaviruses (HCoV) infections. We assessed the seroprevalence of SARS-CoV-2 and seasonal HCoV specific antibodies in a large cohort in north-eastern France. METHODS: In this cross-sectional seroprevalence study, serum samples were collected from children and adults requiring hospital admission for non-COVID-19 between February and August 2020. Antibody responses to SARS-CoV-2 and seasonal HCoV (229E, HKU1, NL63, OC43) were assessed using a bead-based multiplex assay, Luciferase-Linked ImmunoSorbent Assay, and a pseudotype neutralisation assay. FINDINGS: In 2,408 individuals, seroprevalence of SARS-CoV-2-specific antibodies was 7-8% with three different immunoassays. Antibody levels to seasonal HCoV increased substantially up to the age of 10. Antibody responses in SARS-CoV-2 seropositive individuals were lowest in adults 18-30 years. In SARS-CoV-2 seronegative individuals, we observed cross-reactivity between antibodies to the four HCoV and SARS-CoV-2 Spike. In contrast to other antibodies to SARS-CoV-2, specific antibodies to sub-unit 2 of Spike (S2) in seronegative samples were highest in children. Upon infection with SARS-CoV-2, antibody levels to Spike of betacoronavirus OC43 increased across the whole age spectrum. No SARS-CoV-2 seropositive individuals with low levels of antibodies to seasonal HCoV were observed. INTERPRETATION: Our findings underline significant cross-reactivity between antibodies to SARS-CoV-2 and seasonal HCoV, but provide no significant evidence for cross-protective immunity to SARS-CoV-2 infection due to a recent seasonal HCoV infection. In particular, across all age groups we did not observe SARS-CoV-2 infected individuals with low levels of antibodies to seasonal HCoV. FUNDING: This work was supported by the « URGENCE COVID-19 ¼ fundraising campaign of Institut Pasteur, by the French Government's Investissement d'Avenir program, Laboratoire d'Excellence Integrative Biology of Emerging Infectious Diseases (Grant No. ANR-10-LABX-62-IBEID), and by the REACTing (Research & Action Emerging Infectious Diseases), and by the RECOVER project funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No. 101003589, and by a grant from LabEx IBEID (ANR-10-LABX-62-IBEID).

Prospective evaluation of a screening algorithm for carbapenemase-producing Enterobacteriaceae.

BACKGROUND: Carbapenemase-producing Enterobacteriaceae (CPE) have become a major public health issue. The objective of the present study was to prospectively assess the analytical performance of a CPE detection algorithm based on phenotypic tests (the screening test) and MALDI-ToF hydrolysis (the confirmatory test). METHODS: Over a 6-month period and based on a disk diffusion method, 74 carbapenem-resistant strains were included in this study. RESULTS: Of the collected isolates, 54 turned out to be negative after phenotypic tests. Hence, 20 strains (including all of the CPEs) were checked with the confirmation test. Seven strains were positive. After molecular biology assessments in a reference center, three of the seven were found to be false positives. The algorithm had a negative predictive value and a sensitivity of 100%, a specificity of 77%, and a positive predictive value of 20%. CONCLUSION: The algorithm has a 24-hour turnaround time and helps to avoid using expensive molecular biology tests; we consider that it can be used on a routine basis for screening clinical strains.

A case of acute clival osteomyelitis in a 7-year-old boy secondary to infection of a Thornwaldt cyst.

Clival osteomyelitis is a potentially life-threatening infection that can occur in healthy children. It can be related to congenital anomalies. We report the case of a 7-year-old boy with Streptococcus intermedius and Fusobacterium clival osteomyelitis arising from a Thornwaldt cyst situated in a fossa navicularis magna of the occipital bone. Multidisciplinary management is necessary to ensure rapid improvement and complete healing.

Bartholinitis due to Aggregatibacter aphrophilus: a case report.

BACKGROUND: Aggregatibacter aphrophilus, a commensal of the oro-pharyngeal flora and member of the HACEK group of organisms, is an uncommonly encountered clinical pathogen. It has already been described as the causative agent of brain abscesses, empyema, meningitis, sinusitis, otitis media, bacteriemia, pneumonia, osteomyelitis, peritonitis, endocarditis and wound infections. Herein we report the first case of bartholinitis due to A. aphrophilus. CASE PRESENTATION: A 33-year-old woman was admitted for a 3-day genital pain without fever and urinary functional signs. The abscess was incised and drained; A. aphrophilus was the only micro-organism that grew from the pus. The patient received no antibiotics; the clinical course was favourable. CONCLUSION: This case highlights the importance of an effective treatment of recurrent bartholinitis such as a cold resection of the gland. It is presented for its rarity.

Pneumatic transport is critical for leukaemic patients with major leukocytosis: what precautions to measure lactate dehydrogenase, potassium and aspartate aminotransferase?

False elevations of plasma lactate dehydrogenase (LDH), potassium and aspartate aminotransferase (AST) have been described, in relation to haemolysis, occurring most often by mechanical release during phlebotomy or specimen processing. We present the cases of two leukaemic patients with severe hyperleukocytosis for whom LDH, potassium and AST were dramatically but falsely elevated. This false elevation was not caused by haemolysis but could be related to white cells lysis during transport through a pneumatic transportation system, enhanced by a specific fragility of leukaemic cells. Interestingly, this interference almost completely disappeared when serum rather than plasma was used, or when leukocytosis came back to normal. This work is meant to alert clinicians to the risks of errors in LDH, potassium and AST in leukaemic patients and suggest what precautions to take.