Molecular detection of antimicrobial resistance genes in multidrug-resistant Gram-negative bacteria isolated from clinical samples in two hospitals in Niger

Background: According to the World Health Organization (WHO), bacterial resistance to antibiotics is a global public health challenge, which is also developing in Niger. The aim of this study was to determine the prevalence of antibiotic resistance genes in Gram-negative bacilli isolated from clinical samples in the biological laboratories of two selected health facilities in Niger. Methodology: Clinical bacterial isolates were randomly collected from two biological laboratories of Zinder National Hospital and Niamey General Reference Hospital. These were multi-resistant Gram-negative bacteria that have been routinely isolated from pathological samples of patients. Molecular detection of resistance genes was carried out by polymerase chain reaction (PCR) amplification using specific primers. These include plasmid-mediated AmpC beta lactamase genes (blaCITM, blaDHAM, blaFOXM), 'Cefotaxime-Munich' type beta lactamase genes (blaCTX-M-1, blaCTX-M-2, blaCTX-M-9), KPC-type beta lactamase gene (blaKPC), Oxa-type beta lactamase gene (blaOXA-48), SHV-type beta lactamase gene (blaSHV), TEM-type beta lactamase gene (blaTEM), quinolone resistance genes (qnrA, qnrB, qnrS), and sulfonamide resistance genes (sul1, sul2, sul3). Results: A total of 24 strains of multidrug-resistant Gram-negative bacteria isolated from different clinical samples were analysed. The distribution of the resistance genes detected is as follows; AmpC blaCITM (n=6; 25.0%), AmpC blaDHAM (n=4; 17.0%), AmpC blaFOXM (n=0), blaCTX-M-1 (n=11; 46.0%), blaCTX-M-2 (n=0), blaCTX-M-9 (n=0), blaKPC (n=0), blaOXA-48 (n=2; 8..0%), blaSHV (n=5; 21.0%), blaTEM (n=0), qnrA (n=0), qnrB (n=5; 21.0%), qnrS (n=17; 71.0%), sul1 (n=22; 92.0%), sul2 (n=12; 50.0%), and sul3 (n=0). All isolates tested had at least two resistance genes. Conclusion: The results of this study provide a better understanding of the resistance situation of clinical isolates in Niger. Therefore, it is more than necessary to intensify the detection on a larger number of samples and on a national scale. This will make it possible to assess the true extent of the phenomenon and consequently guide control strategies through a national multisectoral plan.

Profile of multidrug-resistant clinical bacterial isolates at the National Hospital of Zinder (NHZ), Niger Republic in 2021

Background: Today, bacterial resistance is a public health challenge throughout the world, and infections caused by resistant bacteria are associated with increased morbidity, mortality and health care costs. The objective of this descriptive study is to determine the prevalence and distribution of multi-drug resistant (MDR) clinical bacteria isolates at the National Hospital of Zinder, Niger Republic in 2021. Methodology: We conducted a descriptive cross-sectional study of in- and out-patients from whose clinical samples' bacteria were isolated at the bacteriology unit of the laboratory. Bacteria were isolated from the clinical samples following standard aerobic cultures and identified using conventional biochemical test schemes. Antibiotic susceptibility testing (AST) was performed by the agar disk diffusion technique, and categorization of the isolates into sensitive, intermediate or resistant was done according to the recommendations of the Antibiogram Committee of the French Society of Microbiology (CA-SFM) 2020 version 1.2. MDR was defined as resistance to at least one antibiotic in three or more categories, while selected MDR bacteria such as ESBL was identified using double disk synergy test, and MRSA by cefoxitin disk diffusion test. Results: Seventy-seven (6.7%) bacterial species were isolated from 1153 clinical samples processed at the bacteriology unit of the hospital laboratory between June and December 2021, of which 65.0% (50/77) were members of the order Enterobacteriales. Escherichia coli represented 40.3% (40/77) of the isolated bacteria, Staphylococcus aureus 13.0% (10/77) and Pseudomonas aeruginosa 11.7% (9/77). The overall prevalence of MDR was 44.2% (34/77), including 61.8% (21/34) ESBL-producing Enterobacteriales (ESBL-E), 26.5% (9/34) multi-resistant P. aeruginosa and 11.7% (4/34) MRSA, with 67.6% (23/34) of the MDR isolates from outpatients. Resistance rates of the Enterobacteriales to ciprofloxacin, gentamicin, amikacin and imipenem were 62.0%, 52.0%, 38.0% and 8.0% respectively. Resistance rates of P. aeruginosa were 100.0%, 88.9%, 77.8%, 33.3%, 22.2%, and 22.2% respectively to ceftazidime, ticarcillin, imipenem, ciprofloxacin, levofloxacin, and amikacin. Resistance rates of S. aureus were 100.0%, 50.0%, 40.0%, 10.0%, 0% and 0% to penicillin G,erythromycin, cefoxitin, tetracycline, fusidic acid, and chloramphenicol respectively. ESBL-E were 47.6%,85.7% and 0% resistant to amikacin, ciprofloxacin and imipenem, and MRSA resistance rates were 75.0%, 75.0%, 50.0% and 0% to erythromycin, tetracycline, gentamicin, and chloramphenicol respectively. Conclusion: This study reports high prevalence of MDR bacteria, mainly ESBL-E, with concerning high resistance to carbapenem. Rational use of antibiotics and implementation of surveillance system for MDR bacteria must be implemented in order to limit the emergence and spread of MDR bacteria in Niger Republic.

Luxibacter massiliensis gen. nov., sp. nov., a new bacterium isolated from the human gut microbiota.

An anaerobic facultative Gram-stain positive bacterium was isolated from human gut microbiota. Strain Marseille-P5551T was considered to be a new genus within the phylum Firmicutes, as it exhibits a 91.87% similarity level with Faecalicatena orotica (NR_117129.1), the phylogenetically closest related species. The draft genome size of strain Marseille-P5551T is 4 142 938 bp with 44.4% of G + C content. We hereby suggest the creation of Luxibacter massiliensis gen. nov., sp. nov., as a new bacterial genus.

Evaluation of the antimicrobial susceptibility testing process in clinical microbiology laboratories at Niamey, Niger

Background: Risk assessment is the means of identifying and evaluating potential errors or problems that may occur in testing process. The aim of this study was to perform risk assessment of antimicrobial susceptibility testing (AST) process in clinical microbiology laboratories of Niamey, Niger Republic. Methodology: We conducted a descriptive cross-sectional study from October 1 to December 31, 2019, to evaluate AST performance in seven clinical microbiology laboratories at Niamey, the capital city of Niger republic. The evaluation focused on the determination of the criticality index (CI) of each critical point (frequency of occurrence of anomalies, severity of the process anomaly, and detectability of the anomaly during the process) in the AST process and the performance of the AST through an observation sheet using two reference strains; Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 29213. Results: The criticality index (CI) was greater than 6 for most of the critical points related to material, medium, equipment, method and labour for the AST process in all the laboratories. A range of 18-100% errors on the inhibition zone diameters of the reference strains were observed. Major and/or minor categorization (Sensitive S, Intermediate I and Resistance R) discrepancies were found at all the laboratories for either one or both reference strains. The antibiotics most affected by the S/I/R discrepancies were trimethoprim (100%), vancomycin (100%), amoxicillin (80%) and amoxicillin + clavulanic acid (70%). Conclusion: This study showed a deficiency in the control of critical control points that impacts the performance of the AST reported by the laboratories in Niger. Corrective actions are needed to improve the performance of AST in clinical microbiology laboratories in Niger

Urinicoccus massiliensis gen. nov., sp. nov., a new bacterium isolated from a human urine sample from a 7-year-old boy hospitalized for dental care.

Urinicoccus massiliensis strain Marseille-P1992T (= CSURP1992 = DSM100581) is a species of a new genus isolated from human urine.

Hémoglobinurie au cours du paludisme grave de l'enfant: Attention au déficit en G6PD à propos de 5 observations

Le paludisme reste un problème majeur de santé publique en Afrique subsaharienne, notamment au Niger où il sévit sur un mode endémique. Un des éléments de gravité est la survenue d'une hémoglobinurie et/ou une anémie. Nous rapportons 5 observations d'anémie par déficit en glucose-6-phosphatase (G6PD) de diagnostic tardif, car mis dans le compte du paludisme grave. Il s'agissait de cinq enfants d'âge moyen de 8,2 ans. 3 des patients étaient de sexe masculin. Tous les cinq patients étaient admis en urgence, référés pour anémie sévère dans un contexte de fièvre. Le nombre moyen d'hospitalisations antérieures était de 4. Les principaux signes à l'admission étaient la pâleur, les douleurs abdominales et des urines couleur porto. La bandelette urinaire a révélé une hémoglobinurie chez tous les patients et une bilirubinurie dans 4 cas. Une notion d'ictère a été retrouvée chez 2 patients, les 3 autres présentaient un ictère clinique. Le taux d'hémoglobine moyen était de 4,4 g/dl. Le taux des plaquettes et le taux de réticulocytes étaient normaux. La goutte épaisse était positive chez tous les patients. Le profil électrophorétique de l'hémoglobine était hétérozygote AS dans 2 cas et homozygote AA dans 3 cas. L'activité enzymatique de la G6PD, dosée à distance de la crise, était effondrée chez tous les patients. Le déficit en G6PD constituant une cause fréquente d'hémoglobinurie et/ou d'anémie chez l'enfant, le bilan étiologique, surtout devant la récurrence de ces signes, devrait en outre comporter un dosage de l'activité enzymatique de la G6PD

In vitro susceptibility of Candida albicans clinical isolates to eight antifungal agents in Ouagadougou (Burkina Faso).

INTRODUCTION: In recent years, the infection Candida albicans infection worldwide has risen, and the incidence of resistance to traditional antifungal therapies is also increasing. The aim of this study was to evaluate in vitro susceptibility of C. albicans clinical isolates to eight antifungal agents in Ouagadougou. MATERIALS AND METHODS: A cross-sectional study was conducted from January 2013 to December 2015 at Yalgado Ouédraogo University Teaching Hospital. Two hundred seven strains have been isolated from 347 symptomatic patients received in different clinical services. Samples were cultured on Sabouraud Dextrose Agar supplemented with Cloramphenicol. Isolates were diagnosed as C. albicans using germ tube test, chlamydospore formation on Corn Meal Agar, and Api-Candida test (Biomérieux). Antifungal susceptibility testing was performed by disk diffusion method and isolates classified as susceptible, susceptible dose-dependent and resistant. RESULTS: Three hundred forty-seven (347) patients are included in this study. Two hundred and six (206) out of 347 collected samples (59.36%) were found positive for C. albicans. The strains were mostly isolated from vulvovaginal (49%) and oral infections (40.3%). The highest resistance rates of azoles were obtained with fluconazole (66.5%), itraconazole (52.3%) and ketoconazole (22.9%) when all clinical isolates were included. The resistance rates of fluconazole, itraconazole and ketoconazole remain highest for vulvovaginal and oral isolates. The rate of resistance to the polyene amphotericin B was 32.0% for all clinical isolates and was 56.4% for vulvovaginal strains. Resistance rate to nystatin was 6.3% for all clinical isolates. Cross-resistance analysis with data of all clinical strains revealed that the incidence of resistance to ketoconazole and itraconazole in fluconazole-resistant isolates was significantly higher than recorded for fluconazole-susceptible isolates. CONCLUSION: In vitro C. albicans antifungal susceptibility test in this study showed relatively high resistance to commonly and widely used azoles (fluconazole, ketoconazole). Most C. albicans clinical isolates were susceptible to nystatin.

Anti-Candida albicans natural products, sources of new antifungal drugs: A review.

INTRODUCTION: Candida albicans is the most prevalent fungal pathogen in humans. Due to the development of drug resistance, there is today a need for new antifungal agents for the efficient management of C. albicans infections. Therefore, we reviewed antifungal activity, mechanisms of action, possible synergism with antifungal drugs of all natural substances experimented to be efficient against C. albicans for future. METHODS: An extensive and systematic review of the literature was undertaken and all relevant abstracts and full-text articles analyzed and included in the review. REVIEW: A total of 111 documents were published and highlighted 142 anti-C. albicans natural products. These products are mostly are reported in Asia (44.37%) and America (28.17%). According to in vitro model criteria, from the 142 natural substances, antifungal activity can be considered as important for 40 (28.20%) and moderate for 24 (16.90%). Sixteen products have their antifungal activity confirmed by in vivo gold standard experimentation. Microbial natural products, source of antifungals, have their antifungal mechanism well described in the literature: interaction with ergosterol (polyenes), inhibition 1,3-ß-d-glucan synthase (Echinocandins), inhibition of the synthesis of cell wall components (chitin and mannoproteins), inhibition of sphingolipid synthesis (serine palmitoyltransferase, ceramide synthase, inositol phosphoceramide synthase) and inhibition of protein synthesis (sordarins). Natural products from plants mostly exert their antifungal effects by membrane-active mechanism. Some substances from arthropods are also explored to act on the fungal membrane. Interestingly, synergistic effects were found between different classes of natural products as well as between natural products and azoles. CONCLUSION: Search for anti-C. albicans new drugs is promising since the list of natural substances, which disclose activity against this yeast is today long. Investigations must be pursued not only to found more new anti-Candida compounds from plants and organisms but also to carried out details on molecules from already known anti-Candida compounds and to more elucidate mechanisms of action.