BackgroundInfections caused by extended-spectrum beta-lactamases producing Enterobacteriaceae (ESBL-E) are of major concern in clinical practice because of limited therapeutic options effective to treat them. Published studies showed that ESBL-E, widely spread in Europe, United States or Asia; are also frequent in Africa. However, the impact of ESBL-E infections is yet to be adequately determined in Sub-Saharan African countries, particularly in Senegal.The aim of our study was to estimate the incidence rate of ESBL-E infections and to assess their clinical and economic impact in Senegal.MethodsTwo retrospective cohort studies were conducted in patients hospitalized from April to October 2012. A classic retrospective cohort study comparing patients infected by an Enterobacteriaceae producer of ESBL (ESBL+) and patients infected by an Enterobacteriaceae non-producer of ESBL (ESBL-) was carried out for fatal outcomes. Besides, a retrospective parallel cohort study comparing infected patients by an ESBL+ and ESBL- versus uninfected patients was carried out for the excess LOS analyses. Multivariable regression analysis was performed to identify risk factors for fatal outcomes. A multistate model and a cost-of-illness analysis were used to estimate respectively the excess length of stay (LOS) attributable to ESBL production and costs associated. Cox proportional hazards models were used to assess the independent effect of ESBL+ and ESBL- infections on LOS.ResultsThe incidence rate of ESBL-E infections was 3 cases/1000 patient-days (95 % CI: 2.4–3.5 cases/1000 patient-days). Case fatality rate was higher in ESBL+ than in ESBL- infections (47.3 % versus 22.4 %, p = 0.0006). Multivariable analysis indicated that risk factors for fatal outcomes were the production of ESBL (OR = 5.7, 95 % CI: 3.2–29.6, p = 0.015) or being under mechanical ventilation (OR = 5.6, 95 % CI: 2.9–57.5, p = 0.030). Newborns and patients suffering from meningitidis or cancer were patients at-risk for fatal outcomes. ESBL production increased hospital LOS (+4 days) and reduced significantly the hazard of discharge after controlling for confounders (HR = 0.3, 95 % CI:0.2–0.4). The additional cost associated with ESBL-production of €100 is substantial given the lower-middle-income status of Senegal.ConclusionOur findings show an important clinical and economic impact of ESBL-E infections in Senegal and emphasize the need to implement adequate infection control measures to reduce their incidence rate. An antibiotic stewardship program is also crucial to preserve the effectiveness of our last-resort antibiotic drugs.

Background Pseudomonas aeruginosa (PA) has a non-clonal, epidemic population with a few widely distributed and frequently encountered sequence types (STs) called ‘high-risk clusters’. Clinical P. aeruginosa (clinPA) has been studied in all inhabited continents excepted in Africa, where a very few isolates have been analyzed. Here, we characterized a collection of clinPA isolates from four countries of West and Central Africa.Methodology184 non-redundant isolates of clinPA from hospitals of Senegal, Ivory Coast, Nigeria, and Central African Republic were genotyped by MLST. We assessed their resistance level to antibiotics by agar diffusion and identified the extended-spectrum β-lactamases (ESBLs) and metallo-β-lactamases (MBLs) by sequencing. The population structure of the species was determined by a nucleotide-based analysis of the entire PA MLST database and further localized on the phylogenetic tree (i) the sequence types (STs) of the present collection, (ii) the STs by continents, (iii) ESBL- and MBL-producing STs from the MLST database.Principal FindingsWe found 80 distinct STs, of which 24 had no relationship with any known STs. ‘High-risk’ international clonal complexes (CC155, CC244, CC235) were frequently found in West and Central Africa. The five VIM-2-producing isolates belonged to CC233 and CC244. GES-1 and GES-9 enzymes were produced by one CC235 and one ST1469 isolate, respectively. We showed the spread of ‘high-risk’ international clonal complexes, often described as multidrug-resistant on other continents, with a fully susceptible phenotype. The MBL- and ESBL-producing STs were scattered throughout the phylogenetic tree and our data suggest a poor association between a continent and a specific phylogroup.ConclusionsESBL- and MBL-encoding genes are borne by both successful international clonal complexes and distinct local STs in clinPA of West and Central Africa. Furthermore, our data suggest that the spread of a ST could be either due to its antibiotic resistance or to features independent from the resistance to antibiotics.

IntroductionCorynebacteria have an important place among the commensal flora of the skin and mucous membranes. Except for Corynebacterium diphtheriae, they were once considered contaminants of mucosa. Recent publications in medical bacteriology have highlighted the importance of several species, such as C. aurimucosum. To the best of our knowledge, we report the first isolation of this strain from urine.Case presentationWe report a case of a patient with a urinary tract infection with C. aurimucosum. We isolated this bacterium from a 52-year-old man of Wolof ethniticity (an ethnic group in Senegal, West Africa) at the regional hospital of Saint Louis, Senegal. Microscopic examination of his total urine sample showed coryneform Gram-positive bacilli associated with a high leukocyte reaction. After repeated isolation of the corynebacteria in three samples from the patient’s urine, it was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The strain was susceptible to antibiotics, except for penicillin and co-trimoxazole. The potential infectious role of these commensal species in several infections should be taken into consideration.ConclusionsThis case highlights the significant proportion of species in the genus Corynebacterium other than dyphteriae in the infectious process. The use of mass spectrometry for identification highlights the originality of this work and the importance of these new diagnostic tools that are unavailable in most health facilities of countries with limited resources. We share the results of our method of identification of the isolated bacteria. This case should prompt attention to these rare bacteria, which can cause severe infections.

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We aimed to detect the extended-spectrum β-lactamases (ESBLs) secreted by clinical strains of Escherichia coli at Fann University Hospital in Dakar and to characterize them molecularly. We identified 32 isolates producing ESBLs. The CTX-M-15 gene was the most frequently detected ESBL gene, detected in 90.63% of the isolates studied.