Characterization of virulence factors in the newly described <i>Salmonella enterica</i> serotype Keurmassar emerging in Senegal (sub-Saharan Africa)

From 2000 to 2001, nine strains of Salmonella enterica belonging to the new serotype Keurmassar have been isolated from human and poultry samples at the Senegalese National Salmonella and Shigella Reference Laboratory at the Pasteur Institute, in Dakar. All strains carried virulence factors including Salmonella Pathogenicity Islands (SPI)-1, -2, -3 and -5 encoded genes. Strains did not harbour virulence plasmid. Ribotyping analysis revealed a single clone identical to Salmonella Decatur isolated in Zimbabwe. These data suggest that strains are closely related, and may have been spread clonally. In this new serotype, insertion sequence IS200 is not present

The Drying Kinetics Study of Couscous for its Conservation,Comsumption and Urban Marketing

The combined effects of the devaluation of the CFA franc in 1992, the food crisis of 2008 and the strong demand for grain products developed urban dwellers have proven to be a necessity of development of grain products manufacturing units marketable and storable without any risk of alteration for cereal craftsmen. This contribution conducted at 40 ° C and 55 ° C with air speeds of 1m / s 2m / s and 3m / s is in the kinetic study of a technological process couscous drying to determine the optimum conditions of the process of dehydration. She found that the drying kinetics of couscous takes place in three phases; indicating that couscous is rich in water and that it can be stored at room temperature unless it is dried. Henceforth it is imperative to have a good knowledge and mastery of these three phases that impact on product quality This study showed that the experiments performed at a speed of air 3m / s at 40 ° C temperatures and 55 ° C, show a brown coloration due to Maillard reactions. We see that the browning phenomena are more pronounced at the speed of 3m / s and 55 ° C. It is found that the slow drying is better suited to the quick dry couscous. In addition to further drying the air velocity of 1m / s correlated with the temperature of 40 ° C is the most suitable as well as good monitoring of the evolution of the temperature during the drying phase warm up for a good product.

Beta-Lactamase-Producing Genes and Integrons in <em>Escherichia coli</em> from Diarrheal Children in Ouagadougou, Burkina Faso

This study aimed to determine the resistance of diarrheagenic Escherichia coli (DEC) strains to β-lactams antibiotics and to perform the molecular characterization of extended-spectrum β-lactamases (ESBLs) and integrons genes. It was carried out from August 2013 to October 2015 and involved 31 DEC strains isolated from diarrheal stools samples collected from children less than 5 years. The identification and characterization of DEC strains were done through the standard biochemical tests that were confirmed using API 20E and polymerase chain reaction (PCR). The antibiogram was realized by the disk diffusion method, then an amplification of the β-lactamase resistance genes and integrons by PCR was done. Out of the 419 E. coli, 31 isolates (7.4%) harbored the DEC virulence genes. From these DEC, 21 (67.7%) were ESBL-producing E. coli. Susceptibility to ESBL-producing E. coli showed that the majority of isolates were highly resistant to amoxicillin (77.4%), amoxicillin-clavulanic acid (77.4%), and piperacillin (64.5%). The following antibiotic resistance genes and integron were identified: blaTEM (6.5%), blaSHV (19.4%), blaOXA (38.7%), blaCTX-M (9.7%), Int1 (58.1%), and Int3 (19.4%). No class 2 integron (Int2) was characterized. Because of the high prevalence of multidrug-resistant ESBL organisms found, there is a need of stringent pediatric infection control measures

Determining the Best Immunization Strategy for Protecting African Children Against Invasive Salmonella Disease.

BACKGROUND: The World Health Organization recently prequalified a typhoid conjugate vaccine (TCV), recommending its use in persons ≥6 months to 45 years residing in typhoid fever (TF)-endemic areas. We now need to consider how TCVs can have the greatest impact in the most vulnerable populations. METHODS: The Typhoid Fever Surveillance in Africa Program (TSAP) was a blood culture-based surveillance of febrile patients from defined populations presenting at healthcare facilities in 10 African countries. TF and invasive non-typhoidal Salmonella (iNTS) disease incidences were estimated for 0-10 year-olds in one-year age increments. RESULTS: Salmonella Typhi and iNTS were the most frequently isolated pathogens; 135 and 94 cases were identified, respectively. Analysis from three countries was excluded (incomplete person-years of observation (PYO) data). Thirty-seven of 123 TF cases (30.1%) and 71/90 iNTS disease cases (78.9%) occurred in children aged <5 years. No TF and 8/90 iNTS infections (8.9%) were observed in infants aged <9 months. The TF incidences (/100 000 PYO) for children aged <1 year and 1 to <2 years were 5 and 39, respectively; the highest incidence was 304 per 100 000 PYO in 4 to <5 year-olds. The iNTS disease incidence in the defined age groups ranged between 81 and 233 per 100 000 PYO, highest in 1 to <2 year-olds. TF and iNTS disease incidences were higher in West Africa. CONCLUSIONS: High burden of TF detected in young children strengthens the need for TCV introduction. Given the concurrent iNTS disease burden, development of a trivalent vaccine against S. Typhi, S. Typhimurium, and S. Enteritidis may be timely in this region

Carbapenem Resistance and Acinetobacter baumannii in Senegal: The Paradigm of a Common Phenomenon in Natural Reservoirs

Incidence of carbapenem-resistant Acinetobacter baumannii is rising in several parts of the world. In Africa, data concerning this species and its resistance to carbapenems are limited. The objective of the present study was to identify the presence of A. baumannii carbapenem-resistant encoding genes in natural reservoirs in Senegal, where antibiotic pressure is believed to be low. From October 2010 to January 2011, 354 human head lice, 717 human fecal samples and 118 animal fecal samples were screened for the presence of A. baumannii by real time PCR targeting blaOXA51-like gene. For all samples positive for A. baumannii, the carbapenemase-hydrolysing oxacillinases blaOXA23-like and blaOXA24-like were searched for and sequenced, and the isolates harbouring an oxacillinase were genotyped using PCR amplification and sequencing of recA gene. The presence of A. baumannii was detected in 4.0% of the head lice, in 5.4% of the human stool samples and in 5.1% of the animal stool samples tested. No blaOXA24 gene was detected but six fecal samples and three lice were positive for blaOXA23-like gene. The blaOXA23-like gene isolated in lice was likely a new oxacillinase sequence. Finally, the A. baumannii detected in stools were all of recA genotype 3 and those detected in lice, of recA genotype 4. This study shows for the first time a reservoir of blaOXA23-like-positive gene in human head lice and stool samples in Senegal

Multicountry Distribution and Characterization of Extended-spectrum β-Lactamase-associated Gram-negative Bacteria From Bloodstream Infections in Sub-Saharan Africa.

BACKGROUND: Antimicrobial resistance (AMR) is a major global health concern, yet, there are noticeable gaps in AMR surveillance data in regions such as sub-Saharan Africa. We aimed to measure the prevalence of extended-spectrum β-lactamase (ESBL) producing Gram-negative bacteria in bloodstream infections from 12 sentinel sites in sub-Saharan Africa. METHODS: Data were generated during the Typhoid Fever Surveillance in Africa Program (TSAP), in which standardized blood cultures were performed on febrile patients attending 12 health facilities in 9 sub-Saharan African countries between 2010 and 2014. Pathogenic bloodstream isolates were identified at the sites and then subsequently confirmed at a central reference laboratory. Antimicrobial susceptibility testing, detection of ESBL production, and conventional multiplex polymerase chain reaction (PCR) testing for genes encoding for β-lactamase were performed on all pathogens. RESULTS: Five hundred and five pathogenic Gram-negative bloodstream isolates were isolated during the study period and available for further characterization. This included 423 Enterobacteriaceae. Phenotypically, 61 (12.1%) isolates exhibited ESBL activity, and genotypically, 47 (9.3%) yielded a PCR amplicon for at least one of the screened ESBL genes. Among specific Gram-negative isolates, 40 (45.5%) of 88 Klebsiella spp., 7 (5.7%) of 122 Escherichia coli, 6 (16.2%) of 37 Acinetobacter spp., and 2 (1.3%) of 159 of nontyphoidal Salmonella (NTS) showed phenotypic ESBL activity. CONCLUSIONS: Our findings confirm the presence of ESBL production among pathogens causing bloodstream infections in sub-Saharan Africa. With few alternatives for managing ESBL-producing pathogens in the African setting, measures to control the development and proliferation of AMR organisms are urgently needed

Etude du rôle des intégrons dans la multirésistance aux antibiotiques des bactéries entéropathogènes isolées en Afrique sub-saharienne

LIMOGES-BU Médecine pharmacie (870852108) / SudocPARIS-BIUP (751062107) / SudocSudocFranceF

Gene Expression in Class 2 Integrons Is SOS-Independent and Involves Two Pc Promoters

Integrons are powerful bacterial genetic elements that permit the expression and dissemination of antibiotic-resistance gene cassettes. They contain a promoter Pc that allows the expression of gene cassettes captured through site-specific recombination catalyzed by IntI, the integron-encoded integrase. Class 1 and 2 integrons are found in both clinical and environmental settings. The regulation of intI and of Pc promoters has been extensively studied in class 1 integrons and the regulatory role of the SOS response on intI expression has been shown. Here we investigated class 2 integrons. We characterized the PintI2 promoter and showed that intI2 expression is not regulated via the SOS response. We also showed that, unlike class 1 integrons, class 2 integrons possess not one but two active Pc promoters that are located within the attI2 region that seem to contribute equally to gene cassette expression. Class 2 integrons mostly encode an inactive truncated integrase, but the rare class 2 integrons that encode an active integrase are associated with less efficient Pc2 promoter variants. We propose an evolutionary model for class 2 integrons in which the absence of repression of the integrase gene expression led to mutations resulting in either inactive integrase or Pc variants of weaker activity, thereby reducing the potential fitness cost of these integrons