scholarly journals Multidrug-Resistant Salmonella enterica Serovar Paratyphi A Harbors IncHI1 Plasmids Similar to Those Found in Serovar Typhi

2007 ◽  
Vol 189 (11) ◽  
pp. 4257-4264 ◽  
Author(s):  
Kathryn E. Holt ◽  
Nicholas R. Thomson ◽  
John Wain ◽  
Minh Duy Phan ◽  
Satheesh Nair ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Salmonella Enterica ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Mobile Elements ◽  
Mobile Dna ◽  
Serovar Typhimurium ◽  
Dna Elements ◽  
Dna Backbone

ABSTRACT Salmonella enterica serovars Typhi and Paratyphi A cause systemic infections in humans which are referred to as enteric fever. Multidrug-resistant (MDR) serovar Typhi isolates emerged in the 1980s, and in recent years MDR serovar Paratyphi A infections have become established as a significant problem across Asia. MDR in serovar Typhi is almost invariably associated with IncHI1 plasmids, but the genetic basis of MDR in serovar Paratyphi A has remained predominantly undefined. The DNA sequence of an IncHI1 plasmid, pAKU_1, encoding MDR in a serovar Paratyphi A strain has been determined. Significantly, this plasmid shares a common IncHI1-associated DNA backbone with the serovar Typhi plasmid pHCM1 and an S. enterica serovar Typhimurium plasmid pR27. Plasmids pAKU_1 and pHCM1 share 14 antibiotic resistance genes encoded within similar mobile elements, which appear to form a 24-kb composite transposon that has transferred as a single unit into different positions into their IncHI1 backbones. Thus, these plasmids have acquired similar antibiotic resistance genes independently via the horizontal transfer of mobile DNA elements. Furthermore, two IncHI1 plasmids from a Vietnamese isolate of serovar Typhi were found to contain features of the backbone sequence of pAKU_1 rather than pHCM1, with the composite transposon inserted in the same location as in the pAKU_1 sequence. Our data show that these serovar Typhi and Paratyphi A IncHI1 plasmids share highly conserved core DNA and have acquired similar mobile elements encoding antibiotic resistance genes in past decades.

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 Alterations of Salmonella enterica Serovar Typhimurium Antibiotic Resistance under Environmental Pressure

2018 ◽  
Vol 84 (19) ◽  
Author(s):  
Mengfei Peng ◽  
Serajus Salaheen ◽  
Robert L. Buchanan ◽  
Debabrata Biswas
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Salmonella Enterica ◽  
Tetracycline Resistance ◽  
Multidrug Resistant ◽  
Genetic Alterations ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Farm Systems ◽  
Serovar Typhimurium

ABSTRACT Microbial horizontal gene transfer is a continuous process that shapes bacterial genomic adaptation to the environment and the composition of concurrent microbial ecology. This includes the potential impact of synthetic antibiotic utilization in farm animal production on overall antibiotic resistance issues; however, the mechanisms behind the evolution of microbial communities are not fully understood. We explored potential mechanisms by experimentally examining the relatedness of phylogenetic inference between multidrug-resistant Salmonella enterica serovar Typhimurium isolates and pathogenic Salmonella Typhimurium strains based on genome-wide single-nucleotide polymorphism (SNP) comparisons. Antibiotic-resistant S. Typhimurium isolates in a simulated farm environment barely lost their resistance, whereas sensitive S. Typhimurium isolates in soils gradually acquired higher tetracycline resistance under antibiotic pressure and manipulated differential expression of antibiotic-resistant genes. The expeditious development of antibiotic resistance and the ensuing genetic alterations in antimicrobial resistance genes in S. Typhimurium warrant effective actions to control the dissemination of Salmonella antibiotic resistance. IMPORTANCE Antibiotic resistance is attributed to the misuse or overuse of antibiotics in agriculture, and antibiotic resistance genes can also be transferred to bacteria under environmental stress. In this study, we report a unidirectional alteration in antibiotic resistance from susceptibility to increased resistance. Highly sensitive Salmonella enterica serovar Typhimurium isolates from organic farm systems quickly acquired tetracycline resistance under antibiotic pressure in simulated farm soil environments within 2 weeks, with expression of antibiotic resistance-related genes that was significantly upregulated. Conversely, originally resistant S. Typhimurium isolates from conventional farm systems lost little of their resistance when transferred to environments without antibiotic pressure. Additionally, multidrug-resistant S. Typhimurium isolates genetically shared relevancy with pathogenic S. Typhimurium isolates, whereas susceptible isolates clustered with nonpathogenic strains. These results provide detailed discussion and explanation about the genetic alterations and simultaneous acquisition of antibiotic resistance in S. Typhimurium in agricultural environments.

scholarly journals Multiple Clones within Multidrug-ResistantSalmonella enterica Serotype Typhimurium Phage Type DT104

2000 ◽  
Vol 38 (3) ◽  
pp. 1269-1271 ◽  
Author(s):  
Antonis Markogiannakis ◽  
Panayotis T. Tassios ◽  
Maria Lambiri ◽  
Linda R. Ward ◽  
Jenny Kourea-Kremastinou ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Gel Electrophoresis ◽  
Salmonella Enterica ◽  
Phage Type ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Pulsed Field Gel Electrophoresis ◽  
Pulsed Field

Six distinct clones were present among Greek multidrug-resistantSalmonella enterica serotype Typhimurium phage type DT104, since isolates belonging to resistance phenotypes including the ACSSuT (ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline) core could be distinguished with respect to their pulsed-field gel electrophoresis patterns, int1 integron structures, and presence or absence of antibiotic resistance genesant(3")-Ia, pse-1, and tem-1.

scholarly journals Diverse and Flexible Transmission of fosA3 Associated with Heterogeneous Multidrug Resistance Regions in Salmonella enterica Serovar Typhimurium and Indiana Isolates

2019 ◽  
Vol 64 (2) ◽  
Author(s):  
Liang-Xing Fang ◽  
Qi Jiang ◽  
Guo-Hui Deng ◽  
Bing He ◽  
Ruan-Yang Sun ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Multidrug Resistance ◽  
Resistance Genes ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Antibiotic Resistance Genes ◽  
Guangdong Province ◽  
Great Flexibility ◽  
Serovar Typhimurium ◽  
M 14

ABSTRACT We identified fosA3 at a rate of 2.6% in 310 Salmonella isolates from food animals in Guangdong province, China. The fosA3 gene was genetically linked to diverse antibiotic resistance genes (ARGs), including mcr-1, blaCTX-M-14/55, oqxAB, and rmtB. These gene combinations were embedded in heterogeneous fosA3-containing multidrug resistance regions on the transferable ST3-IncHI2 and F33:A−:B− plasmids and the chromosome. This indicated a great flexibility of fosA3 cotransmission with multiple important ARGs among Salmonella species.

scholarly journals Distribution of prophages and SGI-1 antibiotic-resistance genes among different Salmonella enterica serovar Typhimurium isolates

Microbiology ◽  
2006 ◽  
Vol 152 (7) ◽  
pp. 2137-2147 ◽  
Author(s):  
Armand P. H. M. Hermans ◽  
Annelien M. Beuling ◽  
Angela H. A. M. van Hoek ◽  
Henk J. M. Aarts ◽  
Tjakko Abee ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Salmonella Enterica ◽  
Phage Type ◽  
Antibiotic Resistance Genes ◽  
Subtractive Hybridization ◽  
The Novel ◽  
Additional Information ◽  
Phage Types ◽  
Serovar Typhimurium

Recently, the authors identified Salmonella enterica serovar Typhimurium (S. Typhimurium) definitive type (DT)104-specific sequences of mainly prophage origin by genomic subtractive hybridization. In the present study, the distribution of the prophages identified, ST104 and ST64B, and the novel prophage remnant designated prophage ST104B, was tested among 23 non-DT104 S. Typhimurium isolates of different phage types and 19 isolates of the DT104 subtypes DT104A, DT104B low and DT104L, and the DT104-related type U302. The four S. Typhimurium prophages Gifsy-1, Gifsy-2, Fels-1 and Fels-2 were also included. Analysis of prophage distribution in different S. Typhimurium isolates may supply additional information to enable development of a molecular method as an alternative to phage typing. Furthermore, the presence of the common DT104 antibiotic resistance genes for the penta-resistance type ACSSuT, aadA2, floR, pse-1, sul1 and tet(G), was also studied because of the authors' focus on this emerging type. Based on differences in prophage presence within their genome, it was possible to divide S. Typhimurium isolates into 12 groups. Although no clear relationship was found between different phage type and prophage presence, discrimination could be made between the different DT104 subtypes based on diversity in the presence of prophages ST104, ST104B and ST64B. The novel prophage remnant ST104B, which harbours a homologue of the Escherichia coli O157 : H7 HldD LPS assembly-related protein, was identified only in the 14 DT104L isolates and in the DT104-related U302 isolate. In conclusion, the presence of the genes for penta-resistance type ACSSuT, the HldD homologue containing ST104 prophage remnant and phage type DT104L are most likely common features of the emerging subtype of S. Typhimurium DT104.

scholarly journals Multidrug-Resistant Enterococci Lack CRISPR-cas

mBio ◽  
2010 ◽  
Vol 1 (4) ◽  
Author(s):  
Kelli L. Palmer ◽  
Michael S. Gilmore
Keyword(s):  
Antibiotic Resistance ◽  
Draft Genome ◽  
Inverse Correlation ◽  
Multidrug Resistant ◽  
Mobile Elements ◽  
Mobile Dna ◽  
Data Set ◽  
Content Type ◽  
Genome Defense ◽  
Acquired Antibiotic Resistance

ABSTRACT Clustered, regularly interspaced short palindromic repeats (CRISPR) provide bacteria and archaea with sequence-specific, acquired defense against plasmids and phage. Because mobile elements constitute up to 25% of the genome of multidrug-resistant (MDR) enterococci, it was of interest to examine the codistribution of CRISPR and acquired antibiotic resistance in enterococcal lineages. A database was built from 16 Enterococcus faecalis draft genome sequences to identify commonalities and polymorphisms in the location and content of CRISPR loci. With this data set, we were able to detect identities between CRISPR spacers and sequences from mobile elements, including pheromone-responsive plasmids and phage, suggesting that CRISPR regulates the flux of these elements through the E. faecalis species. Based on conserved locations of CRISPR and CRISPR-cas loci and the discovery of a new CRISPR locus with associated functional genes, CRISPR3-cas, we screened additional E. faecalis strains for CRISPR content, including isolates predating the use of antibiotics. We found a highly significant inverse correlation between the presence of a CRISPR-cas locus and acquired antibiotic resistance in E. faecalis, and examination of an additional eight E. faecium genomes yielded similar results for that species. A mechanism for CRISPR-cas loss in E. faecalis was identified. The inverse relationship between CRISPR-cas and antibiotic resistance suggests that antibiotic use inadvertently selects for enterococcal strains with compromised genome defense. IMPORTANCE For many bacteria, including the opportunistically pathogenic enterococci, antibiotic resistance is mediated by acquisition of new DNA and is frequently encoded on mobile DNA elements such as plasmids and transposons. Certain enterococcal lineages have recently emerged that are characterized by abundant mobile DNA, including numerous viruses (phage), and plasmids and transposons encoding multiple antibiotic resistances. These lineages cause hospital infection outbreaks around the world. The striking influx of mobile DNA into these lineages is in contrast to what would be expected if a self (genome)-defense system was present. Clustered, regularly interspaced short palindromic repeat (CRISPR) defense is a recently discovered mechanism of prokaryotic self-defense that provides a type of acquired immunity. Here, we find that antibiotic resistance and possession of complete CRISPR loci are inversely related and that members of recently emerged high-risk enterococcal lineages lack complete CRISPR loci. Our results suggest that antibiotic therapy inadvertently selects for enterococci with compromised genome defense.

scholarly journals Environmental Spread of New Delhi Metallo-β-Lactamase-1-Producing Multidrug-Resistant Bacteria in Dhaka, Bangladesh

2017 ◽  
Vol 83 (15) ◽  
Author(s):  
Mohammad Aminul Islam ◽  
Moydul Islam ◽  
Rashedul Hasan ◽  
M. Iqbal Hossain ◽  
Ashikun Nabi ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Resistance Genes ◽  
Tap Water ◽  
Antibiotic Resistance Genes ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
New Delhi ◽  
Multidrug Resistant Bacteria ◽  
Content Type ◽  
Wastewater Samples

ABSTRACT Resistance to carbapenem antibiotics through the production of New Delhi metallo-β-lactamase-1 (NDM-1) constitutes an emerging challenge in the treatment of bacterial infections. To monitor the possible source of the spread of these organisms in Dhaka, Bangladesh, we conducted a comparative analysis of wastewater samples from hospital-adjacent areas (HAR) and from community areas (COM), as well as public tap water samples, for the occurrence and characteristics of NDM-1-producing bacteria. Of 72 HAR samples tested, 51 (71%) samples were positive for NDM-1-producing bacteria, as evidenced by phenotypic tests and the presence of the bla NDM-1 gene, compared to 5 of 41 (12.1%) samples from COM samples (P < 0.001). All tap water samples were negative for NDM-1-producing bacteria. Klebsiella pneumoniae (44%) was the predominant bacterial species among bla NDM-1-positive isolates, followed by Escherichia coli (29%), Acinetobacter spp. (15%), and Enterobacter spp. (9%). These bacteria were also positive for one or more other antibiotic resistance genes, including bla CTX-M-1 (80%), bla CTX-M-15 (63%), bla TEM (76%), bla SHV (33%), bla CMY-2 (16%), bla OXA-48-like (2%), bla OXA-1 (53%), and bla OXA-47-like (60%) genes. Around 40% of the isolates contained a qnr gene, while 50% had 16S rRNA methylase genes. The majority of isolates hosted multiple plasmids, and plasmids of 30 to 50 MDa carrying bla NDM-1 were self-transmissible. Our results highlight a number of issues related to the characteristics and source of spread of multidrug-resistant bacteria as a potential public health threat. In view of the existing practice of discharging untreated liquid waste into the environment, hospitals in Dhaka city contribute to the potential dissemination of NDM-1-producing bacteria into the community. IMPORTANCE Infections caused by carbapenemase-producing Enterobacteriaceae are extremely difficult to manage due to their marked resistance to a wide range of antibiotics. NDM-1 is the most recently described carbapenemase, and the bla NDM-1 gene, which encodes NDM-1, is located on self-transmissible plasmids that also carry a considerable number of other antibiotic resistance genes. The present study shows a high prevalence of NDM-1-producing organisms in the wastewater samples from hospital-adjacent areas as a potential source for the spread of these organisms to community areas in Dhaka, Bangladesh. The study also examines the characteristics of the isolates and their potential to horizontally transmit the resistance determinants. The significance of our research is in identifying the mode of spread of multiple-antibiotic-resistant organisms, which will allow the development of containment measures, leading to broader impacts in reducing their spread to the community.

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