Multidrug resistant bacteria isolated from nosocomial infections at University Teaching Hospital of Point-G, Bamako, Mali.

An infection is said to be nosocomial or hospital if it is absent when the patient enters the hospital and it appears and develops at least 48 h late. The objective of this study was to determine the resistance phenotypes of bacteria isolated from nosocomial infections at the University Teaching Hospital of Point G. Urine, blood, pus, skin and bronchoalveolar fluid samples were taken in different units, and bacteria isolations were performed on usual selective media such as Drigalski Colombia agar supplemented with nalidixic acid and colistin and 5% sheep blood and chocolate agar. Identifications of bacteria such as Enterobacteriaceae, Pseudomonas and acinetobacter, and Staphylococci were done using API20E gallery, API20NE gallery and catalase/oxidase tests, and the Pastorex Staph kit respectively. The antimicrobial susceptibility testing was performed on Mueller-Hinton agar using the diffusion method. A total of 463 patients were inpatients for at least 48 h in the different units, and a nosocomial infection was notified in at least 57 patients (12.3%). A total of 65 episodes of nosocomial infections were observed in these 57 patients. Of the bacteria isolated, multidrug-resistant bacteria (MDR) represented 63.7% (n=36). These were extended-spectrum beta-lactamase (ESBL)-secreting Enterobacteriaceae (n=21), high-level cephalosporinase (n=13) and methicillin-resistant coagulase-negative Staphylococci (n=2). Despite this high number of multi-resistant bacteria isolated in this study; colistin and amikacin had very good activity on enterobacteriaceae. The results show the need to strengthen hygiene in the intensive care units in order to fight against nosocomial infections at the UTH of Point G.

SARS-CoV-2 Neutralizing Responses in Various Populations, at the Time of SARS-CoV-2 Variant Virus Emergence: Evaluation of Two Surrogate Neutralization Assays in Front of Whole Virus Neutralization Test.

The SARS-CoV-2 neutralizing antibodies response is the best indicator of effective protection after infection and/or vaccination, but its evaluation requires tedious cell-based experiments using an infectious virus. We analyzed, in 105 patients with various histories of SARS-CoV-2 infection and/or vaccination, the neutralizing response using a virus neutralization test (VNT) against B.1, Alpha, Beta and Omicron variants, and compared the results with two surrogate assays based on antibody-mediated blockage of the ACE2-RBD interaction (Lateral Flow Boditech and ELISA Genscript). The strongest response was observed for recovered COVID-19 patients receiving one vaccine dose. Naïve patients receiving 2 doses of mRNA vaccine also demonstrate high neutralization titers against B.1, Alpha and Beta variants, but only 34.3% displayed a neutralization activity against the Omicron variant. On the other hand, non-infected patients with half vaccination schedules displayed a weak and inconstant activity against all isolates. Non-vaccinated COVID-19 patients kept a neutralizing activity against B.1 and Alpha up to 12 months after recovery but a decreased activity against Beta and Omicron. Both surrogate assays displayed a good correlation with the VNT. However, an adaptation of the cut-off positivity was necessary, especially for the most resistant Beta and Omicron variants. We validated two simple and reliable surrogate neutralization assays, which may favorably replace cell-based methods, allowing functional analysis on a larger scale.

Characterization of drug resistance and the defective HIV reservoir in virally suppressed vertically infected children in Mali.

BACKGROUND: In the perspective of ART-free HIV remission, vertically infected children treated with suppressive ART from early infancy represent an optimal population model to better understand the genetic complexity of the reservoir. OBJECTIVES: To evaluate the proportion of defective viral population and the genotypic resistance patterns in cell-associated HIV DNA. METHODS: In a cohort including 93 ART-treated vertically HIV-infected (VHIV) children in Mali with plasma HIV-1 RNA ≤50 copies/mL for at least 6 months, we studied total HIV DNA, percentage of defective genomes and resistance by reverse transcriptase and protease bulk sequencing from whole blood in dried blood spots. RESULTS: Children had a median age of 9.9 years at the time of inclusion (IQR = 7.6-13.4) and 3.3 years (IQR = 2-7) at ART initiation; median ART duration was 5.5 years (IQR = 3.7-7.3). The median level of total HIV DNA was 470 copies/106 cells with one patient presenting undetectable HIV DNA (<66 copies/106 cells). We observed the presence of at least one stop codon in viruses from 34 patients (37%). The presence of stop codons was not correlated with the level of HIV DNA or duration of ART. We showed a high prevalence of HIV-1 resistance in DNA with 26% of children harbouring virus resistant to at least one NRTI and 40% to at least one NNRTI. CONCLUSIONS: While these VHIV children were successfully treated for a long time, they showed high prevalence of resistance in HIV DNA and a moderate defective HIV reservoir.

Qualitative and quantitative HIV antibodies and viral reservoir size characterization in vertically infected children with virological suppression.

Background: Absence of detectable viraemia after treatment cessation in some vertically HIV-infected (VHIV) children suggests that early initiation of HAART could lead to functional cure. Objectives: We described the factors associated with HIV antibody levels and the viral reservoir size in HAART-treated VHIV children. Methods: Study included 97 VHIV children with virological suppression, in Bamako, Mali. The anti-gp41 antibody activities and HIV serostatus were assessed. The viral reservoir size was measured by quantifying total cell-associated HIV DNA. Results: Among the children studied, the median total HIV DNA level was 445 copies/10 6 cells (IQR = 187-914) and the median anti-gp41 antibody activity was 0.29 OD (IQR = 0.18-0.75). Low activity of anti-gp41 antibodies was associated with a younger age of HAART initiation ( P = 0.01). Overall, eight HIV-1 seroreversions were identified. Conclusions: Study identified potential candidates with low viral reservoir and low antibody levels or activities for future trials aiming to reduce HIV-1 reservoir to limit HAART duration.