First Report of a Foodborne Salmonella enterica Serovar Gloucester (4:i:l,w) ST34 Strain Harboring blaCTX–M–55 and qnrS Genes Located in IS26-Mediated Composite Transposon

Extended-spectrum β-lactamases (ESBLs) production and (fluoro)quinolone (FQ) resistance among Salmonella pose a public health threat. The objective of this study was the phenotypic and genotypic characterization of an ESBL-producing and nalidixic acid-resistant Salmonella enterica serovar Gloucester isolate (serotype 4:i:l,w) of sequence type 34 (ST34) from ready-to-eat (RTE) meat products in China. Whole-genome short and long read sequencing (HiSeq and MinION) results showed that it contained blaCTX–M–55, qnrS1, and tetB genes, with blaCTX–M–55 and qnrS1 located in chromosomal IS26-mediated composite transposon (IS26–qnrS1–IS3–Tn3–orf–blaCTX–M–55–ISEcp1–IS26). The same genetic structure was found in the chromosome of S. enterica subsp. enterica serovar Typhimurium strain and in several plasmids of Escherichia coli, indicating that the IS26-mediated composite transposon in the chromosome of S. Gloucester may originate from plasmids of E. coli and possess the ability to disseminate to Salmonella and other bacterial species. Besides, the structural unit qnrS1–IS3–Tn3–orf–blaCTX–M–55 was also observed to be linked with ISKpn19 in both the chromosomes and plasmids of various bacteria species, highlighting the contribution of the insertion sequences (IS26 and ISKpn19) to the co-dissemination of blaCTX–M–55 and qnrS1. To our knowledge, this is the first description of chromosomal blaCTX–M–55 and qnrS in S. Gloucester from RTE meat products. Our work expands the host range and provides additional evidence of the co-transfer of blaCTX–M–55 and qnrS1 among different species of Salmonella through the food chain.

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Characterization of mcr-5-Harboring Salmonella enterica subsp. enterica Serovar Typhimurium Isolates from Animal and Food Origin in Germany

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00063-19 ◽

2019 ◽

Vol 63 (6) ◽

Cited By ~ 9

Author(s):

Maria Borowiak ◽

Jens A. Hammerl ◽

Carlus Deneke ◽

Jennie Fischer ◽

Istvan Szabo ◽

...

Keyword(s):

Salmonella Enterica ◽

Mobile Genetic Elements ◽

Sequence Type ◽

Content Type ◽

Genetic Elements ◽

Bacterial Chromosomes ◽

Serovar Typhimurium

ABSTRACT We characterized eight mcr-5-positive Salmonella enterica subsp. enterica serovar Typhimurium sequence type 34 (ST34) isolates obtained from pigs and meat in Germany. Five plasmid types were identified harboring mcr-5 on Tn6452 or putative mobile insertion cassettes. The mobility of mcr-5 was confirmed by integration of Tn6452 into the bacterial chromosomes of two strains and the detection of conjugative mcr-5 plasmids. The association with mobile genetic elements might further enhance mcr-5 distribution.

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Genetic and Biochemical Characterization of Salmonella enterica Serovar Typhi Deoxyribokinase

Journal of Bacteriology ◽

10.1128/jb.182.4.869-873.2000 ◽

2000 ◽

Vol 182 (4) ◽

pp. 869-873 ◽

Cited By ~ 11

Author(s):

Lise Tourneux ◽

Nadia Bucurenci ◽

Cosmin Saveanu ◽

Pierre Alexandre Kaminski ◽

Madeleine Bouzon ◽

...

Keyword(s):

Salmonella Enterica ◽

Biochemical Characterization ◽

Site Directed Mutagenesis ◽

Gene Encoding ◽

E Coli ◽

Salmonella Enterica Serovar Typhi ◽

Acid Protein ◽

Serovar Typhimurium ◽

Amino Acid Protein

ABSTRACT We identified in the genome of Salmonella entericaserovar Typhi the gene encoding deoxyribokinase, deoK. Two other genes, vicinal to deoK, were determined to encode the putative deoxyribose transporter (deoP) and a repressor protein (deoQ). This locus, located between theuhpA and ilvN genes, is absent inEscherichia coli. The deoK gene inserted on a plasmid provides a selectable marker in E. coli for growth on deoxyribose-containing medium. Deoxyribokinase is a 306-amino-acid protein which exhibits about 35% identity with ribokinase from serovar Typhi, S. enterica serovar Typhimurium, or E. coli. The catalytic properties of the recombinant deoxyribokinase overproduced in E. colicorrespond to those previously described for the enzyme isolated from serovar Typhimurium. From a sequence comparison between serovar Typhi deoxyribokinase and E. coliribokinase, whose crystal structure was recently solved, we deduced that a key residue differentiating ribose and deoxyribose is Met10, which in ribokinase is replaced by Asn14. Replacement by site-directed mutagenesis of Met10 with Asn decreased theV max of deoxyribokinase by a factor of 2.5 and increased the K m for deoxyribose by a factor of 70, compared to the parent enzyme.

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Biofilm Formation by Multidrug-Resistant Salmonella enterica Serotype Typhimurium Phage Type DT104 and Other Pathogens

Journal of Food Protection ◽

10.4315/0362-028x-70.1.22 ◽

2007 ◽

Vol 70 (1) ◽

pp. 22-29 ◽

Cited By ~ 48

Author(s):

SHIN-HEE KIM ◽

CHENG-I WEI

Keyword(s):

Stainless Steel ◽

Salmonella Typhimurium ◽

Salmonella Enterica ◽

Bacterial Species ◽

Phage Type ◽

Meat Products ◽

Multidrug Resistant ◽

E Coli ◽

Retail Meat ◽

Glass Surfaces

The biofilm-forming capability of Salmonella enterica serotypes Typhimurium and Heidelberg, Pseudomonas aeruginosa, Listeria monocytogenes, Escherichia coli O157:H7, Klebsiella pneumoniae, and Acinetobacter baumannii isolated from humans, animal farms, and retail meat products was evaluated by using a microplate assay. The tested bacterial species showed interstrain variation in their capabilities to form biofilms. Strong biofilm-forming strains of S. enterica serotypes, E. coli O157: H7, P. aeruginosa, K. pneumoniae, and A. baumannii were resistant to at least four of the tested antibiotics. To understand their potential in forming biofilms in food-processing environments, the strong biofilm formers grown in beef, turkey, and lettuce broths were further investigated on stainless steel and glass surfaces. Among the tested strains, Salmonella Typhimurium phage type DT104 (Salmonella Typhimurium DT104) isolated from retail beef formed the strongest biofilm on stainless steel and glass in beef and turkey broths. K. pneumoniae, L. monocytogenes, and P. aeruginosa were also able to form strong biofilms on the tested surface materials. Salmonella Typhimurium DT104 developed a biofilm on stainless steel in beef and turkey broths through (i) initial attachment to the surface, (ii) formation of microcolonies, and (iii) biofilm maturation. These findings indicated that Salmonella Typhimurium DT104 along with other bacterial pathogens could be a source of cross-contamination during handling and processing of food.

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Functional Analysis of Genes in the rfbLocus of Leptospira borgpetersenii Serovar Hardjo Subtype Hardjobovis

Infection and Immunity ◽

10.1128/iai.68.7.3793-3798.2000 ◽

2000 ◽

Vol 68 (7) ◽

pp. 3793-3798 ◽

Cited By ~ 16

Author(s):

Dieter M. Bulach ◽

Thareerat Kalambaheti ◽

Alejandro de la Peña-Moctezuma ◽

Ben Adler

Keyword(s):

Sequence Similarity ◽

Bacterial Species ◽

Open Reading Frames ◽

New Host ◽

E Coli ◽

Serovar Typhimurium ◽

Genes Encoding ◽

Leptospira Borgpetersenii ◽

Nucleotide Sugars

ABSTRACT Lipopolysaccharide (LPS) is a key antigen in immunity to leptospirosis. Its biosynthesis requires enzymes for the biosynthesis and polymerization of nucleotide sugars and the transport through and attachment to the bacterial membrane. The genes encoding these functions are commonly clustered into loci; for Leptospira borgpetersenii serovar Hardjo subtype Hardjobovis, this locus, named rfb, spans 36.7 kb and contains 31 open reading frames, of which 28 have been assigned putative functions on the basis of sequence similarity. Characterization of the function of these genes is hindered by the fact that it is not possible to construct isogenic mutant strains in Leptospira. We used two approaches to circumvent this problem. The first was to clone the entire locus into a heterologous host system and determine if a “recombinant” LPS or polysaccharide was synthesized in the new host. The second approach used putative functions to identify mutants in other bacterial species whose mutations might be complemented by genes on the leptospiralrfb locus. This approach was used to investigate the function of three genes in the leptospiral rfb locus and demonstrated function for orfH10, which complemented awbpM strain of Pseudomonas aeruginosa, andorfH13, which complemented an rfbW strain ofVibrio cholerae. However, despite the similarity of OrfH11 to WecC, a wecC strain of E. coli was not complemented by orfH11. The predicted protein encoded byorfH8 is similar to GalE from a number of organisms. ASalmonella enterica serovar Typhimurium strain producing no GalE was used as a background in which orfH8 produced detectable GalE enzyme activity.

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Phenotypic and molecular characterization of Salmonella enterica serovar Sofia, an avirulent species in Australian poultry

Microbiology ◽

10.1099/mic.0.047001-0 ◽

2011 ◽

Vol 157 (4) ◽

pp. 1056-1065 ◽

Cited By ~ 8

Author(s):

Emily Gan ◽

Fiona J. Baird ◽

Peter J. Coloe ◽

Peter M. Smooker

Keyword(s):

Salmonella Enterica ◽

Virulence Genes ◽

Meat Products ◽

Virulence Gene ◽

Cleavage Sites ◽

Pathogenic Potential ◽

Serovar Typhimurium ◽

Restriction Cleavage

Salmonella enterica serovar Sofia (S. Sofia) is often isolated from chickens in Australia. However, despite its high frequency of isolation from chicken and chicken meat products, S. Sofia is rarely associated with animal or human salmonellosis, presumably because this serovar is avirulent in nature. The objective of this work was to investigate the phenotypic and molecular properties of S. Sofia in order to assess its pathogenic potential. Our in vivo studies support the observation that this serovar can colonize tissues, but does not cause disease in chickens. This was further confirmed with tissue culture assays, which showed that the ability of S. Sofia to adhere, invade and survive intracellularly is significantly diminished compared with the pathogenic Salmonella enterica serovar Typhimurium (S. Typhimurium) 82/6915. Molecular analysis of Salmonella pathogenicity islands (SPIs) showed that most of the differences observed in SPI1 to SPI5 of S. Sofia could be attributed to minor changes in the sequences, as indicated by a loss or gain of restriction cleavage sites within these regions. Sequence analysis demonstrated that the majority of virulence genes identified were predicted to encode proteins sharing a high identity (75–100 %) with corresponding proteins from S. Typhimurium. However, a number of virulence genes in S. Sofia have accumulated mutations predicted to affect transcription and/or translation. The avirulence of this serovar is probably not the result of a single genetic change but rather of a series of alterations in a large number of virulence-associated genes. The acquisition of any single virulence gene will almost certainly not be sufficient to restore S. Sofia virulence.

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Construction and Characterization of a proU-gfp Transcriptional Fusion That Measures Water Availability in a Microbial Habitat

Applied and Environmental Microbiology ◽

10.1128/aem.68.9.4604-4612.2002 ◽

2002 ◽

Vol 68 (9) ◽

pp. 4604-4612 ◽

Cited By ~ 76

Author(s):

Catherine A. Axtell ◽

Gwyn A. Beattie

Keyword(s):

Pseudomonas Syringae ◽

Water Availability ◽

Water Deprivation ◽

Bacterial Species ◽

Transcriptional Fusion ◽

Bacterial Biosensor ◽

E Coli ◽

Quantitative Manner ◽

Microbial Habitat

ABSTRACT We constructed and characterized a transcriptional fusion that measures the availability of water to a bacterial cell. This fusion between the proU promoter from Escherichia coli and the reporter gene gfp was introduced into strains of E. coli, Pantoea agglomerans, and Pseudomonas syringae. The proU-gfp fusion in these bacterial biosensor strains responded in a quantitative manner to water deprivation caused by the presence of NaCl, Na2SO4, KCl, or polyethylene glycol (molecular weight, 8000). The fusion was induced to a detectable level by NaCl concentrations of as low as 10 mM in all three bacterial species. Water deprivation induced proU-gfp expression in both planktonic and surface-associated cells; however, it induced a higher level of expression in the surface-associated cells. Following the introduction of P. agglomerans biosensor cells onto bean leaves, the cells detected a significant decrease in water availability within only 5 min. After 30 min, the populations were exposed, on average, to a water potential equivalent to that imposed by approximately 55 mM NaCl. These results demonstrate the effectiveness of a proU-gfp-based biosensor for evaluating water availability on leaves. Furthermore, the inducibility of proU-gfp in multiple bacterial species illustrates the potential for tailoring proU-gfp-based biosensors to specific habitats.

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