Diagnostic Performance of Five Rapid Serological Tests for SARS-CoV-2

We conducted a study to evaluate the sensitivity (Se), specificity (Sp), positive predictive value (PPV), and negative predictive value (NPV) of five serologic tests. Subjects with negative or positive COVID-19 polymerase chain reaction (PRC) test results were tested with each of the serological tests. The results were compared with the reference PCR test. For the five tests evaluated, the Se ranged from 55.0% to 70.0% and the Sp ranged from 67.2% to 86.2%. PPV ranged from 53.2% to 80% and NPV from 75.0% to 86.2%. One test, the Wantai, had better specificity and sensitivity. None of the five tests had performance values of more than 90% in the entire sample. In symptomatic positive cases, the Wantai test reported excellent sensitivity. Overall, the low level of diagnostic performance of these tests does not support their use as an alternative to PCR for COVID-19 diagnostic. Test with better performance can be used for mass screening in low prevalence populations, to limit the indiscriminate use of PCR in context of resource-limited countries. Given the excellent sensitivity of Wantai in symptomatic cases, this test could be used as a referral test only in health facilities to discriminate suspected cases before PCR confirmation.

Hematological and Biochemical Profile of Sickle Cell Patients in Critical and Inter-Critical Periods in Brazzaville, Republic of Congo

Introduction: Sickle cell disease is a public health problem in the Republic of Congo where the prevalence of sickle cell trait is estimated at 1.25%. The objective of this study is to describe the variations of hematological and biochemical parameters of hemolysis in sickle cell patients in critical and inter-critical periods. Methods: This is a descriptive cross-sectional study including sickle cell patients followed regularly at the National Reference Center for Sickle Cell Disease (CNRDr) from November 2019 to March 2020. A sample of 167 patients (sickle cell subjects in crisis and in steady state as well as control subjects) was randomly selected during the study period. The blood count was performed using a Sysmex-XN 350 automated system and the biochemical parameters were determined using the Cobas e 311 automated system. Statistical analysis was performed with SPSS version 22 software. Results: The study showed that the mean cholesterol level in controls was 4.16 ± 0.77 ul compared with 9.64 ± 4.34 ul in sickle cell crisis subjects. Hb and HCT levels were significantly higher in controls compared with sickle cell subjects in crisis. During crisis, total bilirubin, direct bilirubin, triglycerides, LDH, AST, and CRP were significantly elevated. Hematological parameters such as Hb and HCT were elevated in controls, while the mean WBC value and RET were higher in sickle cell patients in steady state. The mean values of the biochemical parameters were higher in sickle cell patients in steady state. Conclusion: Evaluation of the influence of sickle cell trait on biochemical and hematological parameters showed significant differences between sickle cell and control subjects.

Phenotypic and Genotypic Characterization of Metallo-Beta-Lactamase and Extended-Spectrum Beta-Lactamase among Enterobacteria Isolated at National Public Health Laboratory of Brazzaville

The improper use of antimicrobials against infectious diseases has allowed microorganisms to develop defense mechanisms that give them insensitivity to these agents. All bacteria are concerned by this phenomenon. This work aimed to assess prevalence of beta-lactamase produced by enterobacterial isolates. Then, disc diffusion, double disc synergy test (DDST) and combined disc test (CDT) were respectively used for antimicrobial resistance, detection of Extended-Spectrum Beta-Lactamases (ESBL) and Metallo-Beta-Lactamases (MBL). bla genes were detected by PCR. A total of 132 enterobacterial strains were studied. Resistance to antibiotic families was observed with a greater frequency than 50%. Gentamicin was the least active beta-lactam antibiotic, with a resistance rate of 88%. 40.9% of strains show an ESBL phenotype and 16.6% were MBL. An overall prevalence of 74% (40/54) and respectively rates of 29.6%, 27.7% and 16.7% for blaSHV, blaCTX and blaTEM genes were observed. SHV, CTX, CTX/SHV/TEM, CTX/TEM, SHV/TEM and CTX/SHV were different ESBL genotypes observed. ESBL-producing enterobacteria isolation worried about the future of antimicrobial therapy in the Republic of Congo. This is a public health problem that requires careful monitoring and implementation of a policy of rational antibiotics use.