Le taux de lymphocytes T CD4 au diagnostic de la séropositivité au virus de l'immunodéficience humaine à Libreville, 2022 / CD4 T lymphocyte count at diagnosis of human immunodeficiency virus seropositivity in Libreville, 2022

Introduction. L'efficacité du traitement antirétroviral dans la restauration immunitaire dépend fortement du stade de l'infection et du taux de lymphocyte TCD4 au moment de l'introduction du traitement. Nous avons évalué le taux de lymphocytes TCD4 à la découverte de la séropositivité au VIH pour caractériser le niveau d'infection de chaque patient. Matériel et méthodes. C'est une étude transversale et descriptive qui s'est déroulée dans le laboratoire de virologie de la faculté de médecine de Libreville. Nous avons analysé les données de la cohorte DERIRADO. Résultats. Nous avons inclus 133 patients. L'âge médian était de 45 ans (Q1-Q3 :37 ; 52). La médiane de LTCD4 était de 388 cellules/mm3 (Q1-Q3 : 250 ; 556). Le diagnostic était avancé chez 112 (84%) patients. Conclusion. La découverte de la séropositivité au Virus de l'Immunodéficience Humaine est faite à un stade d'immunodépression avancé chez la majorité des patients. Ce constat relève la nécessité de mettre en route les politiques de sensibilisation pour cibler les populations clés et amener le plus grand nombre au dépistage de l'infection par le Virus de l'Immunodéficience Humaine si l'on veut diminuer la courbe de transmission.

Introduction. The effectiveness of antiretroviral therapy in immune restoration largely depends on the stage of infection and the TCD4 lymphocyte count at the time of treatment initiation. We evaluated the rate of TCD4 lymphocytes at the discovery of HIV seropositivity to characterize the level of infection of each patient. Methods. This was a cross sectional descriptive and analytic study whose setting was the laboratory of virology of the faculty of medicine of Libreville. Our data source was DERIRADO cohort. Results. We included 133 patients. The median age was 45 (Q1- Q3:37;52). The median LTCD4 was 388 cells/mm3 (Q1-Q3: 250; 556). The diagnosis was advanced in 112 (84%) patients. Conclusion. The diagnosis of seropositivity to the Human Immunodeficiency Virus is made at a stage of immunosuppression in the majority of patients. This highlights the need to implement sensitization policies to target key populations and bring as many people as possible to screening in order to reduce the transmission curve

Submicroscopic Plasmodium falciparum parasitaemia in human immunodeficiency virus-infected adults living in Gabon (Central Africa)-a pilot study.

Background: Submicroscopic malaria infections contribute to malaria transmission. Describing the extent of the parasite reservoir is of importance. In people living with human immunodeficiency virus (HIV), the frequency of subpatent malaria infections is rarely reported. The aim of the present study was to determine the frequency of submicroscopic infections in people living with HIV in Gabon and its relationship with cotrimoxazole (CTX) use. Methods: A survey was conducted in two health care centres in rural areas (Koulamoutou and Oyem) and three in urban areas (Libreville) of Gabon from March 2015 to June 2016. Blood samples were collected from consenting people living with HIV with a negative blood smear. Information on CTX and antiretroviral therapy intake was recorded from the medical file of the patient and through an interview. For molecular analysis, the Plasmodium small subunit ribosomal RNA gene was amplified by nested polymerase chain reaction. Results: Submicroscopic infections were detected in 10.1% (n=12/119) of the people living with HIV, more frequently in those residing in rural areas (15.1%) compared with urban areas (2.1%) (p<0.01). The proportion of anaemic patients was 1.74-fold more frequent in malaria-infected patients, although not statistically significant. Submicroscopic infections frequency did not vary according to CTX intake (p=0.6). Conclusions: The present pilot study highlights a non-negligible frequency of submicroscopic malaria infections in people living with HIV from rural areas, but no relationship with CTX intake was found.

Hepatitis B, C, and E infection among HIV-infected patients in Franceville, Gabon: retrospective cross-sectional study.

Access to antiretrovirals has increased the life expectancy of patients living with HIV. However, HIV-viral hepatitis coinfections in countries endemic for these infections make management more difficult. To determine the extent of these coinfections in Gabon, we investigated markers of hepatitis B, C, and E viruses in 762 adults infected with HIV-1 by ELISA. We used real-time PCR to quantify plasma HBV DNA (HBV VL) and amplified HCV and HEV RNA by nested RT-PCR and PCR.The seroprevalence of chronic hepatitis B infection was 9.3 %. Among patients with isolated HBcAc profiles, the prevalence of occult hepatitis B infection was 26.7 %, for a real prevalence (detectable CV-HBV) of 17.3 % of the total population. HCV seroprevalence was 8.8 %. Of the 67 HIV-positive patients, 76.1 % had replicative profiles (detectable HCV RNA), that is, 6.7 % of the total population. For hepatitis E, seroprevalence was 3.5 %. No case of chronic HEV infection was found. In conclusion, this study highlights a high rate of HIV-Hepatitis B, C and E coinfections in Gabon. In addition, we show the interest of looking for chronic infections (replicative profiles) in HIV-infected patients in Gabon. The establishment of technical platforms for this type of research, accessible to middle-income countries, is necessary.

"Intestinimonas gabonensis" sp. nov., a new bacterium detected from a Gabonese stool specimen.

Detection of new bacteria becomes a major part of culturomics studies coupled with taxonogenomics. Using these strategies, we report here the main characteristics of a new species, "Intestinimonas gabonensis" strain GM5. It is a bacterium isolated from a stool specimen from a 27-year-old man from Gabon.

Discovery of a new species within Bacillus genus in a stool sample from Gabon: "Bacillus massiliogabonensis" sp. nov.

The discovery of new bacteria from the human gut using a culturomics method is a novel field of increasing interest in microbiology. Here the main characteristics of "Bacillus massiliogabonensis" strain Marseille P2639, a new Gram-negative bacterium isolated from the stool sample of a healthy 16-year-old Gabonese boy, are reported.

Noncontiguous finished genome sequence and description of Kallipyga gabonensis sp. nov.

Taxonogenomics coupled with culturomics promotes the isolation and characterization of bacteria. Kallipyga gabonensis sp. nov. strain GM4 is a strictly anaerobic, Gram-positive, and non motile coccus isolated from the stool of a Gabonese male teenager. The genome is 1,621,211 bp long with 50.01% G+C content and two scaffolds. Of the 1,536 predicted genes, 1,475 were protein-coding genes and 61 were RNA genes. A total of 931 genes were assigned a putative function, and 79 genes were identified as ORFans.

Noncontiguous finished genome sequence and description of Gabonia massiliensis gen. nov., sp. nov.

Culturomics coupled with taxonogenomics is currently used to isolate and characterize new bacteria. Here we describe the features and complete genome sequence of Gabonia massiliensis strain GM3, an anaerobic Gram negative, non-spore-forming and catalase-positive bacillus isolated from a stool specimen of a healthy Gabonese male youth. Belonging to a new genus called Gabonia, it exhibits a genome of 4 261 752 bp including 37.9% GC content and 3,288 predicted genes.

Transcriptional activation of the CEF-4/9E3 cytokine gene by pp60v-src.

The CEF-4/9E3 gene is expressed constitutively in Rous sarcoma virus (RSV)-transformed cells. This expression is largely determined by an increase in transcription of the gene. In this report, we characterize the regulatory elements responsible for the transformation-dependent activation of CEF-4/9E3. Three sequences corresponding to AP-1, PRD II/kappa B, and TAACGCAATT are involved in the process and therefore define the src-responsive unit (SRU) of the CEF-4 promoter. In constructs containing a deletion of the SRU, multiple copies of AP-1 or PRD II/kappa B, but not TAACGCAATT, led to activation of the promoter. Thus, factors interacting with these elements are constitutively activated in RSV-transformed chicken embryo fibroblasts. In agreement with the results of transient expression assays, protein binding to AP-1, PRD II/kappa B, and TAACGCAATT were more abundant in the nuclei of transformed cells. The expression of the CEF-4 promoter was investigated in cells infected by a temperature-sensitive mutant of RSV. No significant increase in CEF-4 promoter activity was detected early after activation of pp60v-src. In contrast, a substantial activation of the CEF-4 promoter was detected late after a temperature shift. Factors interacting with the TAACGCAATT, PRD II/kappa B, and AP-1 elements accumulated gradually over a period of several hours. Therefore, transcriptional activation plays an important role in the late, constitutive expression of the CEF-4 gene in stably transformed cells.

Purification of human respiratory syncytial virus: superiority of sucrose gradient over percoll, renografin, and metrizamide gradients.

A method was devised for producing and purifying human respiratory syncytial virus (HRSV) preparations with high titers. Previous attempts to obtain substantial amounts of purified human respiratory syncytial virus have been unsuccessful due to the extreme lability of this virus, its close association with the host cell membrane, and its tendency to aggregate during concentration procedures. We describe a comparative study of various purification media as well as a novel approach for obtaining high titers of HRSV. Virus was produced in HEp-2 cells grown on gelatin beads and concentrated either by precipitation with polyethylene glycol or by centrifugation over a sucrose cushion, the latter yielding 100% recovery. These procedures employed EDTA to disaggregate the virus and MgSO4 as a virus stabilizing agent. Attempts to purify HRSV over percoll, renografin and metrizamide gradients lead to loss of infectivity. Sucrose was found to represent the best purification medium with a yield of up to 60%.

Classification of Vibrio bacteriophages.

85 Vibrio phages, 84 of them tailed and 1 filamentous, were surveyed. The tailed phages belonged to six basic morphotypes and to the Myoviridae, Siphoviridae, or Podoviridae families. 63 phages were classified into 18 species. The filamentous phage is a member of the Inovirus genus of the Inoviridae family. Vibrio phages are very heterogenous and include some morphologically interesting viruses. Several Vibrio phages closely resemble phages of other gram-negative bacteria, possibly indicating phylogenetic relationships between their hosts.