A Constitutively Mannose-Sensitive AgglutinatingSalmonella entericasubsp.entericaSerovar Typhimurium Strain, Carrying a Transposon in the Fimbrial Usher GenestbC, Exhibits Multidrug Resistance and Flagellated Phenotypes

Wu, Kuan Hsun; Wang, Ke Chuan; Lee, Lin Wen; Huang, Yi Ning; Yeh, Kuang‐Sheng

doi:10.1100/2012/280264

Cited by 9 publications

(8 citation statements)

References 28 publications

(37 reference statements)

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“…The ability of the recombinant fimH mutant strains to express a D-mannose binding phenotype was examined by yeast agglutination using an established method [ 25 ]. Briefly, 20 μl of 1 % (v/w) yeast in PBS were mixed with 20 μl of serial dilutions (non-diluted up to 1:16) of bacterial suspensions in PBS (normalised to OD 600 = 0.3) of either MSC95-FimH or mutant strains on a microscopy slide, and the dilution at which agglutination occurred was recorded.…”

Section: Methodsmentioning

confidence: 99%

Adhesion of Escherichia coli under flow conditions reveals potential novel effects of FimH mutations

Feenstra

Thøgersen

Wieser

et al. 2016

Eur J Clin Microbiol Infect Dis

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FimH-mediated adhesion of Escherichia coli to bladder epithelium is a prerequisite for urinary tract infections. FimH is also essential for blood-borne bacterial dissemination, but the mechanisms are poorly understood. The purpose of this study was to assess the influence of different FimH mutations on bacterial adhesion using a novel adhesion assay, which models the physiological flow conditions bacteria are exposed to. We introduced 12 different point mutations in the mannose binding pocket of FimH in an E. coli strain expressing type 1 fimbriae only (MSC95-FimH). We compared the bacterial adhesion of each mutant across several commonly used adhesion assays, including agglutination of yeast, adhesion to mono- and tri-mannosylated substrates, and static adhesion to bladder epithelial and endothelial cells. We performed a comparison of these assays to a novel method that we developed to study bacterial adhesion to mammalian cells under flow conditions. We showed that E. coli MSC95-FimH adheres more efficiently to microvascular endothelium than to bladder epithelium, and that only endothelium supports adhesion at physiological shear stress. The results confirmed that mannose binding pocket mutations abrogated adhesion. We demonstrated that FimH residues E50 and T53 are crucial for adhesion under flow conditions. The coating of endothelial cells on biochips and modelling of physiological flow conditions enabled us to identify FimH residues crucial for adhesion. These results provide novel insights into screening methods to determine the effect of FimH mutants and potentially FimH antagonists.Electronic supplementary materialThe online version of this article (doi:10.1007/s10096-016-2820-8) contains supplementary material, which is available to authorized users.

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Section: Methodsmentioning

confidence: 99%

Adhesion of Escherichia coli under flow conditions reveals potential novel effects of FimH mutations

Feenstra

Thøgersen

Wieser

et al. 2016

Eur J Clin Microbiol Infect Dis

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“…The primers used in this study to amplify the fimbrial genes are listed in Table S1 in the supplemental material. PCR amplification of bcfD, csgA, fimA, lpfD, pefA, safC, sefA, stbD, stfH, sthE, stiH, stjA, and tcfA was performed as described previously (10,(15)(16)(17)(18)(19). PCR primers to amplify the pegD, staA, stcA, stdB, steB, stgA, and stkA genes were established and validated in this study, and the gene accession numbers for the fimbrial genes are shown in Table S1 DNA extraction and PCR.…”

Section: Methodsmentioning

confidence: 99%

Prevalence and Fimbrial Genotype Distribution of Poultry Salmonella Isolates in China (2006 to 2012)

Gong

Zhang

et al. 2014

Appl Environ Microbiol

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(39 isolates, 12.1%). Overall, S. Typhimurium was the most commonly detected serovar; among the individual species, S. Pullorum was most commonly isolated from chickens, S. Enteritidis was most common in ducks, S. Typhimurium was most common in geese and pigeons, and S. enterica serovar Saintpaul was most common in turkeys. PCR determination of 20 fimbrial genes demonstrated the presence of bcfD, csgA, fimA, stdB, and sthE genes and the absence of staA and stgA genes in these isolates, and other loci were variably distributed, with frequency values ranging from 11.8 to 99.1%. These 323 Salmonella isolates were subdivided into 41 different fimbrial genotypes, and of these isolate, 285 strains (88.2%) had 12 to 14 fimbrial genes. Our findings indicated that the Salmonella isolates from different poultry species were phenotypically and genetically diverse and that some fimbrial genes are more frequently associated with serovars or serogroups.

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“…S3 in the supplemental material). Also, earlier work demonstrated that disruption of stbC gene in the stb fimbrial operon could lead strain LT2 to a flagellated strain exhibiting constitutively mannose-sensitive agglutinating and MDR phenotype (41). Interestingly, we detected that, although stbC gene has remained intact, other genes of the stb fimbrial operon, such as stbB, stbA, etc., are lost in the MDR strain T000240 due to the absence of the del_1 cluster.…”

Section: Discussionmentioning

confidence: 61%

Corrected Genome Annotations Reveal Gene Loss and Antibiotic Resistance as Drivers in the Fitness Evolution of Salmonella enterica Serovar Typhimurium

2016

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Horizontal acquisition of novel chromosomal genes is considered to be a key process in the evolution of bacterial pathogens. However, the identification of gene presence or absence could be hindered by the inconsistencies in bacterial genome annotations. Here, we performed a cross-annotation of omnipresent core and mosaic accessory genes in the chromosome of Salmonella enterica serovar Typhimurium across a total of 20 fully assembled genomes deposited into GenBank. Cross-annotation resulted in a 32% increase in the number of core genes and a 3-fold decrease in the number of genes identified as mosaic genes (i.e., genes present in some strains only) by the original annotation. Of the remaining noncore genes, the vast majority were prophage genes, and 255 of the nonphage genes were actually of core origin but lost in some strains upon the emergence of the S. Typhimurium serovar, suggesting that the chromosomal portion of the S. Typhimurium genome acquired a very limited number of novel genes other than prophages. Only horizontally acquired nonphage genes related to bacterial fitness or virulence were found in four recently sequenced isolates, all located on three different genomic islands that harbor multidrug resistance determinants. Thus, the extensive use of antimicrobials could be the main selection force behind the new fitness gene acquisition and the emergence of novel Salmonella pathotypes. IMPORTANCESignificant discrepancies in the annotations of bacterial genomes could mislead the conclusions about evolutionary origin of chromosomal genes, as we demonstrate here via a cross-annotation-based analysis of Salmonella Typhimurium genomes from GenBank. We conclude that despite being able to infect a broad range of vertebrate hosts, the genomic diversity of S. Typhimurium strains is almost exclusively limited to gene loss and the transfer of prophage DNA. Only nonphage chromosomal genes acquired after the emergence of the serovar are linked to the genomic islands harboring multidrug resistance factors. Since the fitness factors could lead to increased virulence, this poses an important research question: could overuse or misuse of antimicrobials act as selection forces for the emergence of more pathogenic strains of Salmonella? H orizontal gene transfer in bacteria is a major force in adaptation to novel environments, in genome diversification, and, in particular, in the evolution of bacterial virulence (1-4). Horizontally transferred genes create a mosaic structure of the species pangenome, where the so-called accessory genes are present only in some strains, in contrast to the core genes that are typically present in all strains (5-7). The chromosomal accessory genes can be subdivided into genes of phage origin and nonphage genes. The latter usually are acquired in the form of genomic islands, episomes, or transposons that are often related to bacterial physiology, antigenic diversification, and thus fitness (4,7,8). In contrast, the phage genes are directly related to phage physiology, although many p...

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A Constitutively Mannose-Sensitive AgglutinatingSalmonella entericasubsp.entericaSerovar Typhimurium Strain, Carrying a Transposon in the Fimbrial Usher GenestbC, Exhibits Multidrug Resistance and Flagellated Phenotypes

Cited by 9 publications

References 28 publications

Adhesion of Escherichia coli under flow conditions reveals potential novel effects of FimH mutations

Adhesion of Escherichia coli under flow conditions reveals potential novel effects of FimH mutations

Prevalence and Fimbrial Genotype Distribution of Poultry Salmonella Isolates in China (2006 to 2012)

Corrected Genome Annotations Reveal Gene Loss and Antibiotic Resistance as Drivers in the Fitness Evolution of Salmonella enterica Serovar Typhimurium

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