Bacteraemia associated with multiple septic localizations caused by Klebsiella pneumoniae sequence type ST660.

We report a case of Klebsiella pneumoniae bacteraemia in an 80-year-old man in France with no history of travel to Asia, complicated by endogenous endophthalmitis, multiple cerebral microbleeds and hepatic microabscesses, associated with a Bentall endocarditis. Hypervirulence pathotype was suggested based on clinical picture, bacterial isolate genomic sequence and hypermucoidy. Interestingly, the isolate had the non-K1/K2-capsular serotype locus KL113-like, carried a KpVP-1-like virulence plasmid, and belonged to the emerging sublineage SL660 (comprising the sequence type ST660).

Risk factors for SARS-CoV-2 infection among health care workers.

BACKGROUND: Health care workers (HCWs) are on the front line for COVID-19. Better knowledge of risk factors for SARS-CoV-2 infection is crucial for their protection. We aimed to identify these risk factors with a focus on care activities. METHODS: We conducted a seroprevalence survey among HCWs in a French referral hospital. Data on COVID-19 exposures, care activities, and protective equipment were collected on a standardized questionnaire. Multivariate logistic regressions were used to assess risk factors for SARS-CoV-2 IgG adjusted on potential confounding. FINDINGS: Among the 3,234 HCWs enrolled, the prevalence of SARS-CoV-2 IgG was 3.8%. Risk factors included contact with relatives or HCWs with COVID-19 (odds ratio [OR] 2.20 [1.40-3.45] and 2.16 [1.46-3.18], respectively), but not contact with COVID-19 patients. In multivariate analyses, suboptimal use of protective equipment during nasopharyngeal sampling (OR 3.46 [1.15-10.40]), mobilisation of patients in bed (OR 3.30 [1.51-7.25]), clinical examination (OR 2.51 [1.16-5.43]), and eye examination (OR 2.90 [1.01-8.35]) were associated with SARS-CoV-2 infection. Patients washing and dressing and aerosol-generating procedures were additional risk factors, with or without appropriate use of protective equipment (OR 1.37 [1.04-1.81] and 1.74 [1.05-2.88]). CONCLUSIONS: Risk factors for SARS-CoV-2 infection among HCWs are (1) contact with relatives or HCWs with COVID-19, (2) close or prolonged contact with patients, (3) aerosol-generating procedures. Enhanced protective measures during the two latter care-activities may be warranted.

Chilblains during lockdown are associated with household exposure to SARS-CoV-2: a multicentre case-control study.

OBJECTIVES: During the COVID-19 pandemic, numerous cases of chilblains have been reported. However, in most cases, RT-PCR or serology did not confirm SARS-CoV-2 infection. Hypotheses have been raised about an interferon-mediated immunological response to SARS-CoV-2, leading to effective clearance of the SARS-CoV-2 without the involvement of humoral immunity. Our objective was to explore the association between chilblains and exposure to SARS-CoV-2. METHODS: In this multicentre case-control study, cases were the 102 individuals referred to five referral hospitals for chilblains occurring during the first lockdown (March to May 2020). Controls were recruited from healthy volunteers' files held by the same hospitals. All members of their households were included, resulting in 77 case households (262 individuals) and 74 control households (230 individuals). Household exposure to SARS-CoV-2 during the first lockdown was categorized as high, intermediate or low, using a pre-established algorithm based on individual data on symptoms, high-risk contacts, activities outside the home and RT-PCR testing. Participants were offered a SARS-CoV-2 serological test. RESULTS: After adjustment for age, the association between chilblains and viral exposure was estimated at OR 3.3, 95% CI (1.4-7.3) for an intermediate household exposure, and 6.9 (2.5-19.5) for a high household exposure to SARS-CoV-2. Out of 57 case households tested, six (11%) had positive serology for SARS-CoV-2, whereas all control households tested (n = 50) were seronegative (p = 0.03). The effect of potential misclassification on exposure has been assessed in a bias analysis. DISCUSSION: This case-control study demonstrates the association between chilblains occurring during the lockdown and household exposure to SARS-CoV-2.

SARS-CoV-2 integral membrane proteins shape the serological responses of patients with COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has elicited a unique mobilization of the scientific community to develop efficient tools to understand and combat the infection. Like other coronavirae, SARS-CoV-2 hijacks host cell secretory machinery to produce viral proteins that compose the nascent virions; including spike (S), envelope (E), and membrane (M) proteins, the most exposed transmembrane proteins to the host immune system. As antibody response is part of the anti-viral immune arsenal, we investigate the immunogenic potential of S, E, and M using a human cell-based system to mimic membrane insertion and N-glycosylation. Both S and M elicit specific Ig production in patients with SARS-CoV-2. Patients with moderate and severe diseases exhibit elevated Ig responses. Finally, reduced Ig binding was observed with spike G614 compared to D614 variant. Altogether, our assay points toward an unexpected immune response against M and represents a powerful tool to test humoral responses against actively evolving SARS-CoV-2 variants and vaccine effectiveness.

Combined use of dried blood spot and rapid molecular systems: A robust solution to monitor hepatitis B virus infection with potential for resource-limited countries.

Chronic hepatitis B (CHB) particularly affects resource-limited countries. CHB management in these areas faces many obstacles for optimal care of patients, including poor access to HBV-DNA quantification, a key marker. This study aims to evaluate the quantification of HBV-DNA on dried blood spots (DBS) using rapid, standardized and fully automated on-demand systems. After a simple and rapid DBS elution protocol, HBV-DNA was simply and accurately quantified on this matrix using two different systems. Limit of quantification was estimated at 400 IU/mL. DBS and plasma HBV-DNA quantification provided comparable results. HBV-DNA stability for up to one month was demonstrated on DBS stored at room temperature, a condition compatible for preservation or transport before analysis. The combined use of DBS and commercially available automated molecular on-demand systems for HBV-DNA quantification could represent a reliable alternative in resource-limited countries to reach remote populations. The good sensitivity of this approach makes it attractive for mother-to-child transmission prevention, treatment decision and follow-up. Costs can be limited if such systems are also validated for other molecular markers.

A lateral flow immunoassay test performance in SARS-CoV-2 seroprevalence surveys: a validation study among healthcare workers.

The objective of this study was to evaluate the validity and reliability of NG-Test® when used as a finger-prick test on healthcare workers and to compare it to the ELISA Wantai Immunoassay. Fifty-one healthcare workers who were RT-PCR SARS-CoV-2 positive and 59 who were RT-PCR SARS-CoV-2 negative accepted to participate in this study. They were subjected to an NG-Test® finger-prick test and collection of a blood sample on the same day. A second NG-Test® on another finger was performed for the first 30 cases and controls and read blinded to the first. Sera obtained from blood samples were used to perform the Wantai SARS-CoV-2 ELISA. The interobserver agreement for the NG-Test® test was perfect (kappa coefficient = 100% [98%-100%]). The sensitivity of NG-Test® was estimated to be 85% [71.9%-92.3%] and the specificity 98.3% [95.0%-100.0%]) for both IgG and IgM. The percentage of agreement between the Wantai immunoassay and NG-Test® was 92.73% for IgG (Kappa = 0.85 [0.75-0.95]) and 65.45% (Kappa = 0.42 [0.26-0.58]) for IgM. Our study highlights the need to validate rapid immunoassay tests under real-life conditions. If NG-Test® is used in seroprevalence surveys, we recommend that its diagnostic performance be taken into consideration to obtain a reliable estimation.