Zoonotic non-typhi salmonella and antibiotic resistance

The Salmonella genus is divided into two species : enterica and bongori. S. enterica itself is subdivided into six subspecies. These different taxons represent over 2,500 serotypes. In France, the number of salmonellosis cases confirmed between 1995 and 1999 is estimated between 32 000 and 43,000 per annum, with 6,000 to 10,700 hospitalisations (and 100 to 560 deaths). Two serotypes are ultra predominant in our country : Typhimurium and Enteritidis. They represent about 70 % of all Salmonella strains isolated in man each year. As observed in most developed countries, the number of non-typhoïdal Salmonella strains isolated in humans in France, multiresistant to antibiotics, and in particular to 3rd generation cephalosporins and quinolones, has been rising steadily over the past five years. The selection of such strains is often due to the use of these classes of antibiotics on animals.Le genre Salmonella est divisé en deux espèces (S. enterica et S. bongori). L'espèce S. enterica est elle-même subdivisée en six sous-espèces. Ces différents taxons sont ensuite subdivisés en plus de 2500 sérotypes. En France, le nombre de cas confirmés de salmonellose chez l'homme entre 1995 et 1999 a été estimé entre 32000 et 43000 par an, avec 6000 à 10700 hospitalisations et 100 à 560 décès. Deux sérotypes Enteritidis et Typhimurium sont ultra-prédominants dans notre pays. Ils représentent environ 70 % de tous les isolements de Salmonella chez l'homme. Parallèlement à ce qui se passe dans la plupart des pays développés, en France, le nombre d'isolats humains de salmonelles non-typhiques multirésistantes aux antibiotiques et en particulier, aux céphalosporines de 3ème génération et aux quinolones, n'a cessé de croître depuis ces cinq dernières années. La sélection de telles souches est souvent consécutive à l'utilisation de ces familles d'antibiotiques chez l'animal

Lack of efflux mediated quinolone resistance in Salmonella enterica serovars Typhi and Paratyphi A.

International audienceSalmonella enterica serovars Typhi and Paratyphi A isolates from human patients in France displaying different levels of resistance to quinolones or fluoroquinolones were studied for resistance mechanisms to these antimicrobial agents. All resistant isolates carried either single or multiple target gene mutations (i.e., in gyrA, gyrB, or parC) correlating with the resistance levels observed. Active efflux, through upregulation of multipartite efflux systems, has also been previously reported as contributing mechanism for other serovars. Therefore, we investigated also the occurrence of non-target gene mutations in regulatory regions affecting efflux pump expression. However, no mutation was detected in these regions in both Typhi and Paratyphi isolates of this study. Besides, no overexpression of the major efflux systems was observed for these isolates. Nevertheless, a large deletion of 2334 bp was identified in the acrS-acrE region of all S. Typhi strains but which did not affect the resistance phenotype. As being specific to S. Typhi, this deletion could be used for specific molecular detection purposes. In conclusion, the different levels of quinolone or FQ resistance in both S. Typhi and S. Paratyphi A seem to rely only on target modifications

Plasmid-mediated multiple antibiotic resistance of Escherichia coli in crude and treated wastewater used in agriculture.

A total of 273 Escherichia coli isolates from raw and treated municipal wastewaters were investigated to evaluate the frequency and persistence of antibiotic resistance and to detect the occurrence of conjugative R plasmids and integrons. The highest resistance rates were against ampicillin (22.71%), tetracycline (19.41%), sulfamethoxazole (16.84%) and streptomycin (14.28%). Multiple antibiotic resistance was present in 24.17% of the isolates. Several multiple antibiotic-resistant isolates proved to be able to transfer en bloc their resistance patterns by conjugative R plasmids with different molecular sizes and restriction profiles. Class 1 integrons of 1 or 1.5 kbp were found in 5 out of 24 representative multiresistant E. coli isolates. Although wastewater treatments proved to be effective in eliminating Salmonella spp. and in reaching WHO microbiological standards for safe use of wastewater in agriculture, they were ineffective in reducing significantly the frequency of plasmid-mediated multiple antibiotic resistance in surviving E. coli. Since multiple antibiotic-resistant bacteria carrying integrons and conjugative R plasmids can constitute a reservoir of antibiotic-resistance genes in wastewater reclaimed for irrigation, risks for public health should be considered. Bacterial strains carrying R plasmids and integrons could contaminate crops irrigated with reclaimed wastewater and transfer their resistances to the consumers' intestinal bacteria

A multiplex real-time PCR assay targeting virulence and resistance genes in Salmonella enterica serotype Typhimurium

<p>Abstract</p> <p>Background</p> <p>Typhimurium is the main serotype of <it>Salmonella enterica </it>subsp. <it>enterica </it>implicated in food-borne diseases worldwide. This study aimed to detect the prevalence of ten markers combined in a macro-array based on multiplex real-time PCR. We targeted characteristic determinants located on pathogenicity islands (SPI-2 to -5, virulence plasmid <it>pSLT </it>and <it>Salmonella </it>genomic island 1 (SGI1)) as well as a specific 16S-23S rRNA intergenic spacer sequence of definitive type 104 (DT104). To investigate antimicrobial resistance, the study also targeted the presence of genes involved in sulfonamide (<it>sul1</it>) and beta-lactam (<it>bla</it>_TEM) resistance. Finally, the <it>intI1 </it>determinant encoding integrase from class 1 integron was also investigated.</p> <p>Results</p> <p>A total of 538 unrelated <it>S</it>. Typhimurium strains isolated between 1999 and 2009 from various sources, including food animals, food products, human and environmental samples were studied. Based on the combined presence or absence of these markers, we distinguished 34 different genotypes, including three major genotypes encountered in 75% of the studied strains, Although SPI determinants were almost always detected, SGI1, <it>intI1</it>, <it>sul1 </it>and <it>bla</it>_TEMdeterminants were found 47%, 52%, 54% and 12% of the time respectively, varying according to isolation source. Low-marker patterns were most often detected in poultry sources whereas full-marker patterns were observed in pig, cattle and human sources.</p> <p>Conclusion</p> <p>The GeneDisc^®assay developed in this study madeit easier to explore variability within serotype Typhimurium by analyzing ten relevant gene determinants in a large collection of strains. This real-time multiplex method constitutes a valuable tool for strains characterization on epidemiological purposes.</p

Ciprofloxacin-resistant Salmonella Kentucky in Travelers

Ciprofloxacin-resistant Salmonella Kentucky in travelers</p

Інформаційний бюлетень як засіб зв'язків із громадкістю протестантської церкви

Shigella sonnei, an emerging global cause of shigellosis, consists of four distinct lineages and the current pandemic involves several geographically associated, multidrug- resistant clones that belong to lineage III (1-3). A typing scheme based on high resolution melting (HRM) of six chromosomal single nucleotide polymorphisms (SNPs) has been described to identify all lineages/sub-lineages (4)

Genomic insights into the emergence and spread of antimicrobial-resistant bacterial pathogens.

Whole-genome sequencing (WGS) has been vital for revealing the rapid temporal and spatial evolution of antimicrobial resistance (AMR) in bacterial pathogens. Some antimicrobial-resistant pathogens have outpaced us, with untreatable infections appearing in hospitals and the community. However, WGS has additionally provided us with enough knowledge to initiate countermeasures. Although we cannot stop bacterial adaptation, the predictability of many evolutionary processes in AMR bacteria offers us an opportunity to channel them using new control strategies. Furthermore, by using WGS for coordinating surveillance and to create a more fundamental understanding of the outcome of antimicrobial treatment and AMR mechanisms, we can use current and future antimicrobials more effectively and aim to extend their longevity

The speciation and hybridization history of the genus Salmonella.

Bacteria and archaea make up most of natural diversity, but the mechanisms that underlie the origin and maintenance of prokaryotic species are poorly understood. We investigated the speciation history of the genus Salmonella, an ecologically diverse bacterial lineage, within which S. enterica subsp. enterica is responsible for important human food-borne infections. We performed a survey of diversity across a large reference collection using multilocus sequence typing, followed by genome sequencing of distinct lineages. We identified 11 distinct phylogroups, 3 of which were previously undescribed. Strains assigned to S. enterica subsp. salamae are polyphyletic, with two distinct lineages that we designate Salamae A and B. Strains of the subspecies houtenae are subdivided into two groups, Houtenae A and B, and are both related to Selander's group VII. A phylogroup we designate VIII was previously unknown. A simple binary fission model of speciation cannot explain observed patterns of sequence diversity. In the recent past, there have been large-scale hybridization events involving an unsampled ancestral lineage and three distantly related lineages of the genus that have given rise to Houtenae A, Houtenae B and VII. We found no evidence for ongoing hybridization in the other eight lineages, but detected subtler signals of ancient recombination events. We are unable to fully resolve the speciation history of the genus, which might have involved additional speciation-by-hybridization or multi-way speciation events. Our results imply that traditional models of speciation by binary fission and divergence are not sufficient to account for Salmonella evolution

One-Step Identification of Five Prominent Chicken Salmonella Serovars and Biotypes.

Based on bacterial genomic data, we developed a one-step multiplex PCR assay to identify Salmonella and simultaneously differentiate the two invasive avian-adapted S. enterica serovar Gallinarum biotypes Gallinarum and Pullorum, and the most frequent, specific, and asymptomatic colonizers of chickens, serovars Enteritidis, Heidelberg, and Kentucky