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Numerous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid serological tests have been developed, but their accuracy has usually been assessed using very few samples, and rigorous comparisons between these tests are scarce. In this study, we evaluated and compared 10 commercially available SARS-CoV-2 rapid serological tests using the STARD (Standards for Reporting of Diagnostic Accuracy Studies) methodology., Numerous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid serological tests have been developed, but their accuracy has usually been assessed using very few samples, and rigorous comparisons between these tests are scarce. In this study, we evaluated and compared 10 commercially available SARS-CoV-2 rapid serological tests using the STARD (Standards for Reporting of Diagnostic Accuracy Studies) methodology. Two hundred fifty serum samples from 159 PCR-confirmed SARS-CoV-2 patients (collected 0 to 32 days after the onset of symptoms) were tested with rapid serological tests. Control serum samples (n = 254) were retrieved from pre-coronavirus disease (COVID) periods from patients with other coronavirus infections (n = 11), positivity for rheumatoid factors (n = 3), IgG/IgM hyperglobulinemia (n = 9), malaria (n = 5), or no documented viral infection (n = 226). All samples were tested using rapid lateral flow immunoassays (LFIAs) from 10 manufacturers. Only four tests achieved ≥98% specificity, with the specificities ranging from 75.7% to 99.2%. The sensitivities varied by the day of sample collection after the onset of symptoms, from 31.7% to 55.4% (days 0 to 9), 65.9% to 92.9% (days 10 to 14), and 81.0% to 95.2% (>14 days). Only three of the tests evaluated met French health authorities’ thresholds for SARS-CoV-2 serological tests (≥90% sensitivity and ≥98% specificity). Overall, the performances varied greatly between tests, with only one-third meeting acceptable specificity and sensitivity thresholds. Knowledge of the analytical performances of these tests will allow clinicians and, most importantly, laboratorians to use them with more confidence; could help determine the general population’s immunological status; and may help diagnose some patients with false-negative real-time reverse transcription-PCR (RT-PCR) results.

The Revogene Carba C assay (formerly GenePOC Carba assay) is a multiplex nucleic acid-based in vitro diagnostic test intended for the detection of carbapenemase-producing Enterobacterales (CPE) from cultured colonies. This assay was evaluated directly on colonies of 118 well-characterized Enterobacterales with reduced susceptibility to carbapenems and on 49 multidrug-resistant (MDR) Pseudomonas aeruginosa and 40 MDR Acinetobacter baumannii isolates., The Revogene Carba C assay (formerly GenePOC Carba assay) is a multiplex nucleic acid-based in vitro diagnostic test intended for the detection of carbapenemase-producing Enterobacterales (CPE) from cultured colonies. This assay was evaluated directly on colonies of 118 well-characterized Enterobacterales with reduced susceptibility to carbapenems and on 49 multidrug-resistant (MDR) Pseudomonas aeruginosa and 40 MDR Acinetobacter baumannii isolates. The Revogene Carba C assay’s performance was high, as it was able to detect the five major carbapenemases (NDM, VIM, IMP, KPC, and OXA-48). In Enterobacterales, sensitivity and specificity were 100%. When extrapolating the results to the French CPE epidemiology between 2012 and 2018, this assay would have detected 99.28% of the 9,624 CPE isolates sent to the French NRC, missing 69 CPE isolates (2 GES-5, 10 OXA-23, 2 TMB-1, 1 SME-4, 53 IMI, and 1 FRI). The overall sensitivity and specificity for CP P. aeruginosa were 93.7 and 100%, respectively, as two rare IMP variants (IMP-31 and -46) were not detected. Extrapolating these results to the French epidemiology of CP P. aeruginosa in 2017, 93.3% would have been identified, missing only 1 DIM and 10 GES variants. The Revogene Carba C assay accurately identified the targeted carbapenemase genes in A. baumannii, but when extrapolating these results to the French CP A. baumannii epidemiology of 2017, only 12.50% of them could be detected, as OXA-23 is the most prevalent carbapenemase in CP A. baumannii. The Revogene Carba C assay showed excellent sensitivity and specificity for the five most common carbapenemases regardless of the bacterial host. It is well adapted to the CPE and CP P. aeruginosa epidemiology of many countries worldwide, which makes it suitable for use in the routine microbiology laboratory, with a time to result of ca. 85 min for eight isolates simultaneously.

As carbapenemase-producing Gram-negative bacilli (CP-GNB) ( Enterobacteriaceae , Pseudomonadaceae , and Acinetobacter spp.) are becoming a major public health issue, there is an urgent need for accurate and fast diagnostic tests. The Amplidiag CarbaR+VRE assay is a multiplex nucleic acid-based in vitro diagnostic test intended for the detection of CP-GNB and vancomycin-resistant enterococci (VRE) from cultured colonies. We have evaluated its ability to detect carbapenemase genes in 100 well-characterized GNB and in 200 consecutive enterobacterial isolates with reduced susceptibility to carbapenems that were referred to the French National Reference Center for carbapenem resistance. The assay has been validated on purified DNA but also directly on colonies. The Amplidiag CarbaR+VRE assay could detect all KPC, NDM, VIM, IMP, and OXA-48-like variants tested and all acquired carbapenem-hydrolyzing oxacillinases from Acinetobacter baumannii (OXA-23, OXA-24/-40, and OXA-58) as well as the overexpressed chromosomally encoded OXA-51-like β-lactamase associated with an upstream inserted IS Aba1 . However, as claimed by the manufacturer, other carbapenemases such as GES-like carbapenemases (GES-2, GES-5, and GES-14), GIM-1, AIM-1, SPM-1, DIM-1, OXA-198 in Pseudomonas aeruginosa , or OXA-143-like in A. baumannii were not detected. Amplidiag CarbaR+VRE's performance values were high (100% sensitivity and 99% specificity) as it could detect the five major carbapenemases—NDM, VIM, IMP, KPC, and OXA-48—as well as OXA-type carbapenemases from Acinetobacter spp. that are currently emerging also among Proteus mirabilis and other enterobacterial isolates. It can provide a result directly from colonies growing on Mueller-Hinton (MH) agar or on selective screening medium in less than 2 h. Further evaluations are now necessary to determine the performance values directly on rectal swabs.

Over a 2½-month period in 1999, 37 ceftazidime-resistant nonrepetitive enterobacterial isolates were collected from 37 patients in a Bangkok hospital, Thailand. Eighty-one percent of these strains expressed a clavulanic acid-inhibited extended-cephalosporin resistance profile. An identical extended-spectrum β-lactamase (ESBL), VEB-1, was found in 16 unrelated enterobacterial isolates (Escherichia coli,n= 10;Enterobacter cloacae,n= 2;Enterobacter sakazakii,n= 1; andKlebsiella pneumoniae,n= 3) and in two clonally relatedE. cloacaeisolates. TheblaVEB-1gene was located on mostly self-conjugative plasmids (ca. 24 to 200 kb) that conferred additional non-β-lactam antibiotic resistance patterns. Additionally, theblaVEB-1gene cassette was part of class 1 integrons varying in size and structure. TheblaVEB-1-containing integrons were mostly associated withblaOXA-10-like andarr-2-like gene cassettes, the latter conferring resistance to rifampin. These data indicated the spread ofblaVEB-1in Bangkok due to frequent transfer of different plasmids and class 1 integrons and rarely to clonally related strains. Plasmid- and integron-mediated resistance to rifampin was also found in enterobacterial isolates.

A Drigalski agar-based culture medium containing an ertapenem, cloxacillin, and zinc sulfate (Supercarba medium) was tested for screening carbapenemase-producing members of the family Enterobacteriaceae . OXA-48 ( n = 44), NDM ( n = 25), VIM or IMP ( n = 27), and KPC producers ( n = 18) were detected with a low detection limit. Its overall sensitivity (95.6%) was higher than those of the currently available ChromID ESBL (bioMérieux) and CHROMagar KPC (CHROMagar) screening media. The Supercarba medium provides a significant improvement for detection of the most common types of carbapenemase producers.

The modified Hodge test has an excellent sensitivity for detecting enterobacterial isolates producing Ambler class A (KPC) and class D (OXA-48) carbapenemases. Its sensitivity is low for NDM-1 producers (50%) but is increased to 85.7% by adding ZnSO 4 (100 μg/ml) in the culture medium. However, this test has a low specificity and is time-consuming.