(1) Background: The detection of SARS-CoV-2 RNA in nasopharyngeal samples through real-time reverse transcription-polymerase chain reaction (RT-PCR) is considered the standard gold method for the diagnosis of SARS-CoV-2 infection. Antigen detection (AD) tests are more rapid, less laborious, and less expensive alternatives but still require clinical validation. (2) Methods: This study compared the clinical performance of five AD tests, including four rapid AD (RAD) tests (biotical, Panbio, Healgen, and Roche) and one automated AD test (VITROS). For that purpose, 118 (62.8%) symptomatic patients and 70 (37.2%) asymptomatic subjects were tested, and results were compared to RT-PCR. (3) Results: The performance of the RAD tests was modest and allowed us to identify RT-PCR positive patients with higher viral loads. For Ct values ≤25, the sensitivity ranged from 93.1% (95% CI: 83.3–98.1%) to 96.6% (95% CI: 88.1–99.6%), meaning that some samples with high viral loads were missed. Considering the Ct value proposed by the CDC for contagiousness (i.e., Ct values ≤33) sensitivities ranged from 76.2% (95% CI: 65.4–85.1%) to 88.8% (95% CI: 79.7–94.7%) while the specificity ranged from 96.3% (95% CI: 90.8–99.0%) to 99.1% (95% CI: 95.0–100%). The VITROS automated assay showed a 100% (95% CI: 95.5–100%) sensitivity for Ct values ≤33, and had a specificity of 100% (95% CI: 96.6–100%); (4) Conclusions: Compared to RAD tests, the VITROS assay fully aligned with RT-PCR for Ct values up to 33, which might allow a faster, easier and cheaper identification of SARS-CoV-2 contagious patients.

A yellow-pigmented coryneform rod was isolated from the blood of a child with acute lymphoblastic leukemia who was perfused with a central venous catheter. The culture bottles were positive twice, at a 2-month interval. The isolate was identified as a Microbacterium sp. and studied along with five other similar strains. Phenotypic, chemotaxonomic, and genetic characteristics indicated that they are closely related to Microbacterium oxydans but that they belong to a distinct species, for which the name Microbacterium paraoxydans sp. nov. is proposed. The type strain of M. paraoxydans is CF36T ‫؍‬ DSM 15019 T . The G؉C content of its DNA is 69.9 mol%. CASE REPORTA 5-year-old boy was diagnosed with acute lymphoblastic leukemia in December 1994 and included in the Fralle 93 protocol. The child achieved hematologic remission 6 weeks after induction chemotherapy was initiated. He was seen as an outpatient and responded well to treatment in the following years. However, at a March 1997 consultation, the patient had a febrile episode when being perfused with the Port-a-cath system. Clinical examination showed no septic localization. The leukocyte count was 10,860/ml, with an absolute neutrophil count of 8,850/ml. One set of blood cultures was collected from the Port-a-cath, and the aerobic bottle culture yielded yellow-pigmented colonies of gram-positive coryneform rods. The boy received ceftriaxone (1 g) intravenously once, followed by cefadroxil 500 mg twice a day for 7 days. Because of a persistent fever, cefadroxil was given for another week and immunosuppressive drugs were discontinued during the same period. The patient's history was unremarkable for the next 2 months, and no blood culture was performed when he came for his monthly visits. In June 1997, the child was presented for consultation as subfebrile and complaining of fatigue. A physical examination revealed no focus of infection, and the leukocyte count was not elevated. One set of blood cultures was taken from the Port-a-cath, and the aerobic vial revealed the same gram-positive coryneform rods, subsequently identified as Microbacterium sp. Catheter-related bacteremia was diagnosed, and the central venous catheter was removed. Ampicillin (100 mg/kg/day) was given intravenously perioperatively, with the first dose given 24 h prior to surgery. The patient's clinical condition improved rapidly afterwards. The Port-a-cath was cultured on Columbia blood agar. Within 24 h at 37°C, a pure culture of yellow-pigmented colonies of a nonfermentative, gram-positive, somewhat discolored rod had grown. Unfortunately, subcultures were lost and no further examination could be performed.The strain isolated from the patient's blood cultures, labeled CF36, was a yellow-pigmented, motile coryneform with an oxidative metabolism, proteolytic activity, and cellular fatty acids of the branched type. These general features are suggestive of the genus Microbacterium, which includes both fermentative and oxidative species, the latter formerly called Aureobacterium (13).The 16S rRN...

Three strains of coryneform rods isolated from clinical samples and one of environmental origin exhibited phenotypic and chemotaxonomic properties characteristic of the genus Brevibacterium and their 16S rRNA gene sequences were closely related (98?5-99?0 %) to that of Brevibacterium otitidis. However, DNA-DNA hybridization of one strain (CF87 T ) showed only 59?6 % relatedness to the type strain of B. otitidis, DSM 10718 T , and 75-82 % relatedness to the three other strains. The four strains could be differentiated from B. otitidis by cellular fatty acid composition and some phenotypic characteristics. These findings suggest that the four strains belong to a novel species, for which the name Brevibacterium lutescens sp. nov. is proposed. The type strain of B. lutescens is CF87T (=DSM 15022Recently, a coryneform bacterium belonging to the genus Brevibacterium was reported as a cause of peritonitis in a patient undergoing continuous ambulatory peritoneal dialysis (Wauters et al., 2000b). Its conventional phenotypic characteristics were consistent with those of Brevibacterium otitidis, and 16S rRNA gene sequencing revealed 98?8 % similarity to the sequence of the type strain of that species, which was rather low, but compatible with membership of the same species (Stackebrandt & Goebel, 1994). Later, three B. otitidis-like strains were collected that exhibited a mean of 98?8 % similarity to B. otitidis in their 16S rRNA sequences, two from clinical samples and one from the environment. They were studied more extensively along with the peritonitis strain. A few phenotypic characteristics and DNA-DNA hybridization results clearly indicated that the four strains, including the peritonitis strain, belonged to a novel species, closely related to but distinct from B. otitidis, for which the name Brevibacterium lutescens sp. nov. is proposed.The four novel strains were of human and environmental origin. Strain CF87 T was isolated from peritoneal fluid (Wauters et al., 2000b), strain CF32 from an infected ear discharge, strain CF60 from a peritoneal dialysate fluid and strain CF100 from a peptone preparation. They were stored in glycerol at 220 u C and cultured on blood agar at 37 u C in air for the purposes of this study. T , DSM 13658, DSM 13659 and DSM 13660. In addition, the following clinical isolates from our collection were included in the study: one B. otitidis strain (CF65), confirmed by 16S rRNA gene sequencing and by DNA-DNA hybridization, and eight B. casei and seven B. paucivorans strains, all of them confirmed by 16S rRNA gene sequencing.Most phenotypic characteristics were studied as described previously (Funke et al., 1997;Wauters et al., 1998Wauters et al., , 2000aWauters et al., , 2001. Pyrrolidonyl arylamidase, a-glucosidase and N-acetylb-D-glucosaminidase were tested using diagnostic tablets (Rosco). Assimilation/alkalinization of c-aminobutyric acid was tested using Simmons' citrate agar, replacing citrate by 0?1 % (w/v) of the substrate. Acid production from phenylacetate was examined as follows...

Strategies to detect SARS-CoV-2 are increasingly being developed. Among them, serological methods have been developed. Nevertheless, although these may present an interesting clinical performance, they are often directed against only one antigen. This study aims at evaluating the clinical performance of an innovative multiplex immunoassay (i.e., CoViDiag assay) detecting simultaneously the presence of antibodies directed against N, S1, S2, RBD and NTD antigens. Sensitivity was evaluated in 135 samples obtained from 94 rRT-PCR confirmed coronavirus disease 2019 (COVID-19) patients. Non-SARS-CoV-2 sera (n = 132) collected before the COVID-19 pandemic with potential cross-reactions to the SARS-CoV-2 immunoassay were included in the specificity analysis. The antibody signature was also studied in hospitalized and non-hospitalized patients. The specificity of the CoViDiag assay was excellent for all antibodies (99.2 to 100%) using adapted cut-offs. None of the false positive samples were positive for more than one antibody. The sensitivity obtained from samples collected 14 days since symptom onset varied from 92.0 to 100.0% depending on the antibody considered. Among samples collected more than 14 days after symptom onset, 12.8, 66.3, 3.5, 9.3, 5.8 and 2.3% were positive for 5, 4, 3, 2, 1 or 0 antibodies, respectively. A trend toward higher antibody titers was observed in hospitalized patient in the early days since symptom onset. However, no significant difference was observed compared to non-hospitalized patients after 14 days since symptom onset. The clinical performance of the CoViDiag 5 IgG assay is sufficient to recommend its use for the detection and the characterization of the antibody signature following SARS-CoV-2 infection. The combination of several antigens in the same test improves the overall specificity and sensitivity of the test. Further research is needed to investigate whether this strategy may be of interest to identify severe disease outcome in patients with SARS-CoV-2 infection.

Six hundred nineteen strains of nonfermenting gram-negative rods were tested for alkaline phosphatase, benzyl-arginine arylamidase, pyrrolidonyl arylamidase, ethylene glycol acidification, and susceptibility to desferrioxamine and colistin. The results were highly discriminant. Therefore, the proposed tests may be helpful for the identification of this group of organisms.Identification of gram-negative nonfermenting rods by conventional methods is often difficult and time-consuming, and commercial systems do not always provide reliable identification, especially of some genera or species (7,17,19). Moreover, recent taxonomic studies resulted in the description of an increasing number of new genera and species involved in nosocomial infections and requiring additional tests for identification. This was true, for instance, for the new genus Ralstonia (2, 3, 14), the former "Flavobacterium" group (12, 13), and others. In this study, we investigated a large number of strains for six biochemical and susceptibility characteristics that are rarely or not at all included in conventional schemes. Alkaline phosphatase (PHO), benzyl-arginine arylamidase (BAA), and pyrrolidonyl arylamidase (PYR), three enzymatic tests, are sometimes included in commercial systems, but they are not systematically reported in existing identification schemes (4, 6, 11). Susceptibility to desferrioxamine has been proposed for the identification of coagulase-negative staphylococci (9) but not for gram-negative bacilli. Acid production from ethylene glycol was described in corynebacteria (20) but, as far as we know, has not been evaluated in nonfermenters. We have also included susceptibility to colistin, although susceptibility to polymyxin B is often mentioned in conventional schemes (4, 6, 11), but low colistin content disks may yield slightly different results.Five hundred fifty-three clinical isolates of nonfermenting gram-negative rods and 66 reference strains, including type strains, were tested. They included 41 species or Centers for Disease Control and Prevention (CDC) groups (Table 1). Only fast growers on tryptic soy agar were investigated. Moraxella spp. and other fastidious nonfermenters were excluded, as were Acinetobacter spp. because the latter can be identified on the basis of a few simple routine tests. All tests and cultures were performed at 30°C. For enzymatic reactions, diagnostic tablets from ROSCO (Taastrup, Denmark) were used in accordance with the manufacturer's instructions with slight modifications. Tablets were put in 0.5 ml of a 3 to 4 McFarland bacterial suspension and incubated for 4 h. Reading of BAA and PYR was done after addition of 1 drop of cinnamaldehyde reagent. PHO turned yellow when positive; no color or a pale yellowish color was considered negative. Determination of acid production from ethylene glycol was performed as previously described (20). Susceptibility to desferrioxamine was determined on Mueller-Hinton agar using 6-mm-diameter paper disks loaded with 250 g of desferrioxamine (9). Testing for su...