Comparative evaluation of Panbio and SD Biosensor antigen rapid diagnostic tests for COVID-19 diagnosis

The aim of our study was to evaluate the diagnostic performance of two antigen rapid diagnostic tests (Ag‐RDTs) to diagnose severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection. We evaluated Panbio and SD‐Biosensor Ag‐RDTs. We employed 186 polymerase chain reaction (PCR) negative samples to evaluate the specificity and 170 PCR positive samples to assess the sensitivity. We evaluated their sensitivity according to Cycle threshold (Ct) values and days post onset of symptoms (d.p.o.). Tests were compared using the McNemar's test. Agreement was evaluated using the kappa score. Specificity was 100% for Panbio and 97.3% for SD‐Biosensor. Sensitivity for samples with Ct ≤ 20 was 100% for both assays and for samples with Ct = 20–25 was 93.0% (Panbio) and 95.3% (SD‐Biosensor) (p = 1.000). Sensitivity decreased for samples wit Ct = 25–30 (Panbio: 41.3%, SD‐Biosensor: 52.2%, p = 0.125) and samples with Ct ≥ 30 (Panbio: 5.0%, SD‐Biosensor: 17.5%, p = 0.063). Sensitivity within seven d.p.o. was 87.7% for Panbio and 90.4% for SD‐Biosensor and notably decreased after seven d.p.o. Agreement with PCR was excellent for high viral load samples (Ct ≤ 25): Panbio, 98.9%, kappa = 0.974; SD‐Biosensor, 97.4%, kappa = 0.940. Agreement between Ag‐RDTs was excellent (94.9%, kappa = 0.882). Panbio and SD‐Biosensor Ag‐RDTs showed excellent agreement and diagnostic performance results for samples with high viral loads (Ct ≤ 25) or samples within seven d.p.o

Diagnostic performance of CerTest and Panbio antigen rapid diagnostic tests to diagnose SARS-CoV-2 infection

Objectives Antigen rapid diagnostic tests (Ag-RDT) have been developed as reliable tools to control the SARS-CoV-2 pandemic. The objective of our study was to evaluate the diagnostic performance of two Ag-RDTs. Methods We evaluated CerTest SARS-CoV-2 Ag One Step Card Test and Panbio COVID-19 Ag Rapid Test Device Ag-RDTs. We included 320 nasopharyngeal samples: 150 PCR negative samples to assess the specificity and 170 PCR positive samples to evaluate the sensitivity. We also evaluated their sensitivity according to cycle threshold (Ct) values and the time from the onset of symptoms. Tests were compared using the McNemar?s test and agreement was evaluated using the kappa score (k). Results Both Ag-RDTs showed a specificity of 100 %. Overall sensitivity was 53.5 % for CerTest and 60.0 % for Panbio. For samples with 25, sensitivity was 94.0 % for CerTest and 96.4 % for Panbio (p = 0.500). Regarding samples with Ct>25, sensitivity was 14.0 % for CerTest and 24.4 % for Panbio (p = 0.004). Sensitivity for samples within the first 5 days after the onset of symptoms were 84.8 % for CerTest and 91.3 % for Panbio (p = 0.250) and notably decreased for samples taken after the fifth day. Both Ag-RDTs showed an excellent agreement between them (agreement = 96.7 %, k = 0.920). Agreement with PCR was also excellent for high viral load samples (Ct<25) for CerTest (98.0 %, k = 0.954) and Panbio (98.8 %, k = 0.973). Conclusions CerTest SARS-CoV-2 and Panbio COVID-19 Ag showed excellent performance and agreement results for samples with high viral loads (Ct 25) or samples taken within the first 5 days after the onset of symptoms

Study of susceptibility to antibiotics and molecular characterization of high virulence Staphylococcus aureus strains isolated from a rural hospital in Ethiopia.

We characterised 80 Staphylococcus aureus strains isolated from human patients with SSTIs at a rural hospital in Ethiopia. Susceptibility to antibiotic of all strains was tested. The MLST method was used to type and a phylogenetic analysis was conducted employing the sequences of 7 housekeeping genes. PCR amplification was used to investigate the presence of the following virulence genes in all strains: hla (α-haemolysin), tstH (toxic shock syndrome toxin), luk PV (Panton-Valentine leukocidin), fnbA (fibronectin binding protein A) and mecA (methicillin resistance). Most of the strains were resistant to penicillin and ampicillin, but only 3 strains were resistant to oxacillin, and 1 of them was a true MRSA. The MLST results showed a high diversity of sequence types (ST), 55% of which were new, and ST152 was the most prevalent. A phylogeny study showed that many of the new STs were phylogenetically related to other previously described STs, but bore little relationship to the only ST from Ethiopia described in the database. Virulence gene detection showed a high prevalence of strains encoding the hla, fnbA and pvl genes (98.77%, 96.3% and 72.84%, respectively), a low prevalence of the tst gene (13.58%) and a markedly low prevalence of MRSA (1.25%). S. aureus strains isolated from patients in a rural area in Ethiopia showed low levels of antibiotic resistance, except to penicillin. Moreover, this study reveals new STs in Eastern Africa that are phylogenetically related to other previously described STs, and confirm the high prevalence of the pvl gene and the low prevalence of MRSA on the continent

Genotypic and Phenotypic Characteristics of Staphylococcus aureus Prosthetic Joint Infections: Insight on the Pathogenesis and Prognosis of a Multicenter Prospective Cohort

Background. Staphylococcus aureus is the leading cause of prosthetic joint infection (PJI). Beyond the antibiogram, little attention has been paid to the influence of deep microbiological characteristics on patient prognosis. Our aim was to investigate whether microbiological genotypic and phenotypic features have a significant influence on infection pathogenesis and patient outcome.Methods. A prospective multicenter study was performed, including all S. aureus PJIs (2016-2017). Clinical data and phenotypic (agr functionality, beta-hemolysis, biofilm formation) and genotypic characteristics of the strains were collected. Biofilm susceptibility to antimicrobials was investigated (minimal biofilm eradication concentration [MBEC] assay).Results. Eighty-eight patients (39.8% men, age 74.7 +/- 14.1 years) were included. Forty-five had early postoperative infections (EPIs), 21 had chronic infections (CPIs), and 19 had hematogenous infections (HIs). Twenty (22.7%) were caused by methicillin-resistant S. aureus. High genotypic diversity was observed, including 16 clonal complexes (CCs), with CC5 being the most frequent (30.7%). agr activity was greater in EPI than CPI (55.6% vs 28.6%; P = .041). Strains causing EPI were phenotypically and genotypically similar, regardless of symptom duration. Treatment failure (36.5%) occurred less frequently among cases treated with implant removal. In cases treated with debridement and implant retention, there were fewer failures among those who received combination therapy with rifampin. No genotypic or phenotypic characteristics predicted failure, except vancomycin minimal inhibitory concentration >= 1.5 mg/L (23.1% failure vs 3.4%; P = .044). MBEC(50 )was >128 mg/L for all antibiotics tested and showed no association with prognosis.Conclusions. S. aureus with different genotypic backgrounds is capable of causing PJI, showing slight differences in clinical presentation and pathogenesis. No major microbiological characteristics were observed to influence the outcome, including MBEC