scholarly journals Emergence of DHA-1-Producing Klebsiella spp. in the Parisian Region: Genetic Organization of the ampC and ampR Genes Originating from Morganella morganii

2006 ◽  
Vol 50 (2) ◽  
pp. 607-617 ◽  
Author(s):  
Charlotte Verdet ◽  
Yahia Benzerara ◽  
Valérie Gautier ◽  
Olivier Adam ◽  
Zahia Ould-Hocine ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Klebsiella Oxytoca ◽  
Gene Cassette ◽  
Genomic Region ◽  
Clinical Isolates ◽  
Morganella Morganii ◽  
Reading Frame ◽  
Genetic Organization ◽  
Transporter Family ◽  
Serovar Typhimurium

ABSTRACT Eleven Klebsiella pneumoniae clinical isolates and one Klebsiella oxytoca clinical isolate showing various pulsed-field gel electrophoresis types and producing an inducible DHA-1 class C β-lactamase were isolated in the Parisian region between 1998 and 2003. The aim of this study was to compare the genetic organization of the bla DHA-1 genes in this collection of clinical isolates. In four isolates, the Morganella morganii-derived genomic region containing bla DHA-1 was inserted in an entire complex sul1-type integron, including a region common to In6-In7 (CR1), as previously described in a bla DHA-1-producing Salmonella enterica serovar Enteritidis KF92 isolate from Saudi Arabia in 1992. Different gene cassette arrays were characterized in each of these integrons. In two of them, an additional 10-kb fragment was inserted between the CR1 and the M. morganii-derived region and was similar to the sap (ABC transporter family) and psp (phage shock protein) operons originated from Salmonella enterica serovar Typhimurium. The length of the M. morganii region was variable, suggesting that several independent recombination events have occurred and that open reading frame orf513 encodes a recombinase involved in the mobilization of the resistance genes. The genetic organization of bla DHA-1 was identical in the eight other isolates. This structure is likely derived from a complex integron following the insertion of IS26, leading to the deletion of the first part of integron. The horizontal transfer of one plasmid carrying that truncated integron was shown for seven of these isolates.

Removal of pathogenic bacterial biofilms by combinations of oxidizing compounds

2015 ◽  
Vol 61 (5) ◽  
pp. 351-356 ◽  
Author(s):  
Gabriela María Olmedo ◽  
Mariana Grillo-Puertas ◽  
Luciana Cerioni ◽  
Viviana Andrea Rapisarda ◽  
Sabrina Inés Volentini
Keyword(s):  
Staphylococcus Aureus ◽  
Salmonella Enterica ◽  
Klebsiella Oxytoca ◽  
Fold Increase ◽  
Clinical Isolates ◽  
Bacterial Biofilms ◽  
Simultaneous Application ◽  
E Coli ◽  
Serovar Typhimurium ◽  
And Staphylococcus Aureus

Bacterial biofilms are commonly formed on medical devices and food processing surfaces. The antimicrobials used have limited efficacy against the biofilms; therefore, new strategies to prevent and remove these structures are needed. Here, the effectiveness of brief oxidative treatments, based on the combination of sodium hypochlorite (NaClO) and hydrogen peroxide (H2O2) in the presence of copper sulfate (CuSO4),were evaluated against bacterial laboratory strains and clinical isolates, both in planktonic and biofilm states. Simultaneous application of oxidants synergistically inactivated planktonic cells and prevented biofilm formation of laboratory Escherichia coli, Salmonella enterica serovar Typhimurium, Klebsiella pneumoniae, and Staphylococcus aureus strains, as well as clinical isolates of Salmonella enterica subsp. enterica, Klebsiella oxytoca, and uropathogenic E. coli. In addition, preformed biofilms of E. coli C, Salmonella Typhimurium, K. pneumoniae, and Salmonella enterica exposed to treatments were removed by applying 12 mg/L NaClO, 0.1 mmol/L CuSO4, and 350 mmol/L H2O2for 5 min. Klebsiella oxytoca and Staphylococcus aureus required a 5-fold increase in NaClO concentration, and the E. coli clinical isolate remained unremovable unless treatments were applied on biofilms formed within 24 h instead of 48 h. The application of treatments that last a few minutes using oxidizing compounds at low concentrations represents an interesting disinfection strategy against pathogens associated with medical and industrial settings.

scholarly journals Antibiotic Resistance Genes and Salmonella Genomic Island 1 in Salmonella enterica Serovar Typhimurium Isolated in Italy

2002 ◽  
Vol 46 (9) ◽  
pp. 2821-2828 ◽  
Author(s):  
Alessandra Carattoli ◽  
Emma Filetici ◽  
Laura Villa ◽  
Anna Maria Dionisi ◽  
Antonia Ricci ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Salmonella Enterica ◽  
Genomic Island ◽  
Antibiotic Resistance Genes ◽  
Tetracycline Resistance ◽  
Gene Cassette ◽  
Multidrug Resistant ◽  
Phage Types ◽  
Serovar Typhimurium

ABSTRACT Fifty-four epidemiologically unrelated multidrug-resistant Salmonella enterica serovar Typhimurium isolates, collected between 1992 and 2000 in Italy, were analyzed for the presence of integrons. Strains were also tested for Salmonella genomic island 1 (SGI1), carrying antibiotic resistance genes in DT104 strains. A complete SGI1 was found in the majority of the DT104 strains. Two DT104 strains, showing resistance to streptomycin-spectinomycin and sulfonamides, carried a partially deleted SGI1 lacking the flost , tetR, and tetA genes, conferring chloramphenicol-florfenicol and tetracycline resistance, and the integron harboring the pse-1 gene cassette, conferring ampicillin resistance. The presence of SGI1 was also observed in serovar Typhimurium strains belonging to other phage types, suggesting either the potential mobility of this genomic island or changes in the phage-related phenotype of DT104 strains.

scholarly journals Identification of Bacterial Species That Can Utilize Fructose-Asparagine

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
Anice Sabag-Daigle ◽  
Jikang Wu ◽  
Mikayla A. Borton ◽  
Anindita Sengupta ◽  
Venkat Gopalan ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Culture Media ◽  
Bacterial Species ◽  
Klebsiella Oxytoca ◽  
Foodborne Pathogen ◽  
Toxic Metabolite ◽  
Toxicity Assay ◽  
Content Type ◽  
Serovar Typhimurium ◽  
Utilization Pathway

ABSTRACTSalmonella entericaserovar Typhimurium is the only organism demonstrated to utilize fructose-asparagine (F-Asn) as a source of carbon and nitrogen. In this report, we first used a bioinformatics approach to identify other microorganisms that encode homologs of theSalmonellaF-Asn utilization enzymes FraB (deglycase), FraD (kinase), and FraE (asparaginase). These candidate organisms were then tested with up to four different methods to confirm their ability to utilize F-Asn. The easiest and most broadly applicable method utilized a biological toxicity assay, which is based on the observation that F-Asn is toxic to aSalmonella fraBmutant. Candidate organisms were grown in a rich medium containing F-Asn, and depletion of F-Asn from the medium was inferred by the growth of aSalmonella fraBmutant in that same medium. For select organisms, the toxicity assay was cross-validated by direct mass spectrometry-aided measurement of F-Asn in the spent-culture media and through demonstration of FraB and FraD enzyme activity in cellular extracts. For prototrophs, F-Asn utilization was additionally confirmed by growth in a minimal medium containing F-Asn as the sole carbon source. Collectively, these studies established thatClostridiumbolteae,Clostridium acetobutylicum, andClostridium clostridioformecan utilize F-Asn, butClostridium difficilecannot;Klebsiella oxytocaand someKlebsiella pneumoniaesubspecies can utilize F-Asn; and someCitrobacter rodentiumandCitrobacter freundiistrains can also utilize F-Asn. WithinSalmonella enterica, the host-adapted serovars Typhi and Paratyphi A have lost the ability to utilize F-Asn.IMPORTANCEFructose-asparagine (F-Asn) is a precursor to acrylamide that is found in human foods, and it is also a nutrient source forSalmonella enterica, a foodborne pathogen. Here, we determined that among the normal intestinal microbiota, there are species ofClostridiumthat encode the enzymes required for F-Asn utilization. Using complementary experimental approaches, we have confirmed that three members ofClostridium, two members ofKlebsiella, and two members ofCitrobactercan indeed utilize F-Asn. TheClostridiumspp. likely compete withSalmonellafor F-Asn in the gut and contribute to competitive exclusion. FraB, one of the enzymes in the F-Asn utilization pathway, is a potential drug target because inhibition of this enzyme leads to the accumulation of a toxic metabolite that inhibits the growth ofSalmonellaspecies. This study identifies the potential off-target organisms that need to be considered when developing therapeutics directed at FraB.

scholarly journals Extensive Genetic Variability Linked to IS26Insertions in thefljBPromoter Region of Atypical Monophasic Variants of Salmonella enterica Serovar Typhimurium

2015 ◽  
Vol 81 (9) ◽  
pp. 3169-3175 ◽  
Author(s):  
Cécile Boland ◽  
Sophie Bertrand ◽  
Wesley Mattheus ◽  
Katelijne Dierick ◽  
Vicky Jasson ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Promoter Region ◽  
Variable Number Tandem Repeat ◽  
Genetic Alterations ◽  
Variable Number ◽  
Genomic Region ◽  
Phase 2 ◽  
Pathogenic Potential ◽  
Content Type ◽  
Serovar Typhimurium

ABSTRACTFifty-nine monophasicSalmonella entericaserovar Typhimurium isolates, collected in Belgium during the period from 2008 to 2011, have been serotyped as 4,[5]:i:− and shown to harbor anfljBcoding sequence. The genetic differences between these strains and phenotypically biphasicSalmonellaTyphimurium were analyzed through PCR and DNA sequencing. Genetic alterations in thefljBpromoter region affecting expression of the phase 2 flagellin were observed in 53 isolates. Other genetic events in the invertible region carrying thefljBpromoter were observed in 2 isolates. For the remaining 4 isolates, no molecular differences with a reference biphasicSalmonellaTyphimurium strain could be observed. Next-generation sequencing of one representative isolate affected in thefljBpromoter region revealed a 26-kb IS26composite transposon insertion along with a local genomic rearrangement. Several other IS26element-mediated alterations of this genomic region were observed. This group of monophasicSalmonellaTyphimurium isolates was genetically heterogeneous, as revealed by multilocus variable-number tandem-repeat analysis (MLVA), PCR, and sequencing. Pigs and pork represented a major source of such monophasic isolates in Belgium, as reported in other countries. Three out of 5 isolates of human origin presented genetic profiles identical to those of food isolates, demonstrating the pathogenic potential of the newly characterized variants and potential dissemination along the food chain. This study highlighted the key role played by IS26insertions in the loss of phase 2 flagellin expression and the subsequent generation of multiple monophasic variant lineages from biphasicSalmonellaTyphimurium ancestors.

scholarly journals A Novel Integron in Salmonella enterica Serovar Enteritidis, Carrying the blaDHA-1 Gene and Its Regulator Gene ampR, Originated fromMorganella morganii

2000 ◽  
Vol 44 (1) ◽  
pp. 222-225 ◽  
Author(s):  
Charlotte Verdet ◽  
Guillaume Arlet ◽  
Guilene Barnaud ◽  
Philippe H. Lagrange ◽  
Alain Philippon
Keyword(s):  
Resistance Genes ◽  
Salmonella Enterica ◽  
Specific Site ◽  
Regulator Gene ◽  
Morganella Morganii ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Genetic Organization ◽  
Gene Coding

ABSTRACTThe genetic organization of the gene coding for DHA-1 and the correspondingampRgene was determined by PCR mapping. These genes have been mobilized from theMorganella morganiichromosome and inserted into a complexsulI-type integron, similar to In6 and In7. However, they are not themselves mobile cassettes. This integron probably includes a specific site for recombination allowing the mobilization of diverse resistance genes, as observed forblaCMY-1andblaMOX-1.

scholarly journals Transcriptional Organization and Function of Invasion Genes within Salmonella enterica Serovar Typhimurium Pathogenicity Island 1, Including the prgH,prgI, prgJ, prgK, orgA,orgB, and orgC Genes

2000 ◽  
Vol 68 (6) ◽  
pp. 3368-3376 ◽  
Author(s):  
Joanna R. Klein ◽  
Thomas F. Fahlen ◽  
Bradley D. Jones
Keyword(s):  
Epithelial Cells ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Pathogenicity Island ◽  
Pcr Analysis ◽  
Intestinal Epithelial ◽  
Reading Frame ◽  
Bacterial Proteins ◽  
Serovar Typhimurium ◽  
And Function

ABSTRACT Salmonella enterica serovar Typhimurium initiates infection of a host by inducing its own uptake into specialized M cells which reside within the epithelium overlaying Peyer's patches. Entry of Salmonella into intestinal epithelial cells is dependent upon invasion genes that are clustered together inSalmonella pathogenicity island 1 (SPI-1). Upon contact between serovar Typhimurium and epithelial cells targeted for bacterial internalization, bacterial proteins are injected into the host cell through a type III secretion system that leads to internalization of the bacteria. Previous work has established that the prgH, -I, -J, and -K and orgAgenes reside in SPI-1, and the products of these genes are predicted to be components of the invasion secretion apparatus. We report that an error in the published orgA DNA sequence has been identified so that this region encodes two small genes rather than a single large open reading frame. These genes have been designatedorgA and orgB. Additionally, an opening reading frame downstream of orgB, which we have designatedorgC, has been identified and partially characterized. Previously published work has indicated that the prgH, -I, -J, and -K genes are transcribed from a promoter distinct from that used by the gene immediately downstream, orgA. Here, we present experiments indicating that orgA expression is driven by theprgH promoter. In addition, using reverse transcriptase PCR analysis, we have found that this polycistronic message extends downstream of prgH to include a total of 10 genes. To more fully characterize this invasion operon, we demonstrate that theprgH, prgI, prgJ, prgK,orgA, and orgB genes are each required for invasion and secretion, while orgC is not essential for the invasive phenotype.

scholarly journals The cobZ Gene of Methanosarcina mazei Gö1 Encodes the Nonorthologous Replacement of the α-Ribazole-5′-Phosphate Phosphatase (CobC) Enzyme of Salmonella enterica

2006 ◽  
Vol 188 (7) ◽  
pp. 2740-2743 ◽  
Author(s):  
Carmen L. Zayas ◽  
Jesse D. Woodson ◽  
Jorge C. Escalante-Semerena
Keyword(s):  
Salmonella Enterica ◽  
High Performance ◽  
Inducible Promoter ◽  
Ionization Mass ◽  
Reading Frame ◽  
Methanosarcina Mazei ◽  
Nickel Affinity Chromatography ◽  
Serovar Typhimurium

ABSTRACT Open reading frame (ORF) Mm2058 of the methanogenic archaeon Methanosarcina mazei strain Gö1 was shown in vivo and in vitro to encode the nonorthologous replacement of the α-ribazole-phosphate phosphatase (CobC; EC 3.1.3.73) enzyme of Salmonella enterica serovar Typhimurium LT2. Bioinformatics analysis of sequences available in databases tentatively identified ORF Mm2058, which was cloned under the control of an inducible promoter and was used to support growth of an S. enterica strain under conditions that demanded CobC-like activity. The Mm2058 protein was expressed with a decahistidine tag at its N terminus and was purified to homogeneity using nickel affinity chromatography. High-performance liquid chromatography followed by electrospray ionization mass spectrometry showed that the Mm2058 protein had phosphatase activity that converted α-ribazole-5′-phosphate to α-ribazole, as reported for the bacterial CobC enzyme. On the basis of the data reported here, we refer to ORF Mm2058 as cobZ. We tested the prediction by Rodionov et al. (D. A. Rodionov, A. G. Vitreschak, A. A. Mironov, and M. S. Gelfand, J. Biol. Chem. 278:41148-41159, 2003) that ORF HSL01294 (also called Vng1577) encoded the nonorthologous replacement of the bacterial CobC enzyme in the extremely halophilic archaeon Halobacterium sp. strain NRC-1. A strain of the latter carrying an in-frame deletion of ORF Vng1577 was not a cobalamin auxotroph, suggesting that either there is redundancy of this function in Halobacterium or the gene was misannotated.

scholarly journals Osmoregulated periplasmic glucans of Salmonella enterica serovar Typhimurium are required for optimal virulence in mice

Microbiology ◽  
2009 ◽  
Vol 155 (1) ◽  
pp. 229-237 ◽  
Author(s):  
Arvind A. Bhagwat ◽  
Won Jun ◽  
Liu Liu ◽  
Porteen Kannan ◽  
Mahesh Dharne ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Type Strain ◽  
Wild Type Strain ◽  
Gene Cassette ◽  
Growth Conditions ◽  
Kanamycin Resistance ◽  
Wild Type ◽  
Serovar Typhimurium ◽  
Resistance Gene Cassette ◽  
Reduced Rate

We purified osmoregulated periplasmic glucans (OPGs) from Salmonella enterica serovar Typhimurium and found them to be composed of 100 % glucose with 2-linked glucose as the most abundant residue, with terminal glucose, 2,3-linked and 2,6-linked glucose also present in high quantities. The two structural genes for OPG biosynthesis, opgG and opgH, form a bicistronic operon, and insertion of a kanamycin resistance gene cassette into this operon resulted in a strain devoid of OPGs. The opgGH mutant strain was impaired in motility and growth under low osmolarity conditions. The opgGH mutation also resulted in a 2 log increase in the LD50 in mice compared to the wild-type strain SL1344. Inability to synthesize OPGs had no significant impact on the organism's lipopolysaccharide pattern or its ability to survive antimicrobial peptides-, detergent-, pH- and nutrient-stress conditions. We observed that the opgGH-defective strain respired at a reduced rate under acidic growth conditions (pH 5.0) and had lower ATP levels compared to the wild-type strain. These data indicate that OPGs of S. Typhimurium contribute towards mouse virulence as well as growth and motility under low osmolarity growth conditions.

scholarly journals opdA, a Salmonella enterica Serovar Typhimurium Gene Encoding a Protease, Is Part of an Operon Regulated by Heat Shock

2000 ◽  
Vol 182 (2) ◽  
pp. 518-521 ◽  
Author(s):  
Christopher A. Conlin ◽  
Charles G. Miller
Keyword(s):  
Escherichia Coli ◽  
Heat Shock ◽  
Sigma Factor ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Temperature Shift ◽  
Open Reading Frame ◽  
Gene Encoding ◽  
Reading Frame ◽  
Serovar Typhimurium

ABSTRACT The opdA (prlC) gene of Salmonella enterica serovar Typhimurium and Escherichia coliencodes the metalloprotease oligopeptidase A (OpdA). We report thatopdA is cotranscribed with a downstream open reading frame,yhiQ. Transcription of this operon is induced after a temperature shift (30 to 42°C), and this induction depends on the heat shock sigma factor encoded by the rpoH(htpR) gene.

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