scholarly journals Emergence of mcr-1-Harboring Salmonella enterica Serovar Sinstorf Type ST155 Isolated From Patients With Diarrhea in Jiangsu, China

2021 ◽  
Vol 12 ◽  
Author(s):  
Guoye Liu ◽  
Huimin Qian ◽  
Jingwen Lv ◽  
Benshun Tian ◽  
Changjun Bao ◽  
...  
Keyword(s):  
Southern Blot ◽  
Gel Electrophoresis ◽  
Blot Hybridization ◽  
Southern Blot Hybridization ◽  
Pulsed Field Gel Electrophoresis ◽  
Sequencing Analysis ◽  
Colistin Resistance ◽  
Pulsed Field ◽  
Extended Spectrum Beta Lactamase ◽  
Pcr Method

Background: This study analyzed the antimicrobial resistance phenotypes and mechanisms of quinolone, cephalosporins, and colistin resistance in nontyphoidal Salmonella from patients with diarrhea in Jiangsu, China.Methods: A total of 741 nontyphoidal Salmonella isolates were collected from hospitals in major cities of Jiangsu Province, China between 2016 and 2017. Their susceptibility to commonly used antibiotics was evaluated by broth micro-dilution and sequencing analysis of resistance genes screened by a PCR method. For mcr-1 positive isolates, genetic relationship study was carried out by pulsed-field gel electrophoresis and multiloci sequence typing analysis. The transferability of these plasmids was measured with conjugation experiments and the genetic locations of mcr-1 were analyzed by pulsed-field gel electrophoresis profiles of S1-digested genomic DNA and subsequent Southern blot hybridization.Results: Among 741 nontyphoidal Salmonella isolates, the most common serotypes identified were S. Typhimurium (n=257, 34.7%) and S. Enteritidis (n=127, 17.1%), and the isolates showed 21.7, 20.6, and 5.0% resistance to cephalosporins, ciprofloxacin, and colistin, respectively. Among the 335 nalidixic acid-resistant Salmonella, 213 (63.6%) and 45 (13.4%) had at least one mutation in gyrA and parC. Among the plasmid-borne resistance, qnrS1 (85; 41.9%) and aac(6')-Ib-cr4 (75; 36.9%) were the most common quinolone resistance (PMQR) genes, while blaCTX-M-14 (n=35) and blaCTX-M-55 (n=46) were found to be dominant extended-spectrum beta-lactamase (ESBL) genes in nontyphoidal Salmonella. In addition, eight mcr-1-harboring strains were detected since 2016 and they were predominate in children under the age of 7years. Conjugation assays showed the donor Salmonella strain has functional and transferable colistin resistance and Southern blot hybridization revealed that mcr-1 was located in a high molecular weight plasmid.Conclusion: In nontyphoidal Salmonella, there is a rapidly increasing trend of colistin resistance and this is the first report of patients harboring mcr-1-positive Salmonella with a new ST type ST155 and new serotype S. Sinstorf. These findings demonstrate the necessity for cautious use and the continuous monitoring of colistin in clinical applications.

scholarly journals Pulsed-Field Gel Electrophoresis Profile Changes Resulting from Spontaneous Chromosomal Deletions in Enterohemorrhagic Escherichia coli O157:H7 during Passage in Cattle

2009 ◽  
Vol 75 (17) ◽  
pp. 5719-5726 ◽  
Author(s):  
Noriyo Yoshii ◽  
Yoshitoshi Ogura ◽  
Tetsuya Hayashi ◽  
Takashi Ajiro ◽  
Toshiya Sameshima ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Enterohemorrhagic Escherichia Coli ◽  
Sequencing Analysis ◽  
Pulsed Field ◽  
Chromosomal Deletions ◽  
Profile Changes ◽  
Dna Sequencing Analysis ◽  
Pfge Profiles

ABSTRACT A total of 905 enterohemorrhagic Escherichia coli (EHEC) O157:H7 isolates that were recovered from experimentally infected cattle, in addition to the inoculated strain, were analyzed by pulsed-field gel electrophoresis (PFGE). Twelve PFGE profiles other than that of the inoculated strain were observed. We successfully identified five distinct chromosomal deletions that affected the PFGE profiles using whole-genome PCR scanning and DNA sequencing analysis. The changes in PFGE profiles of EHEC O157:H7 isolates after passage through the intestinal tract of cattle were partially generated by deletion of chromosomal regions.

scholarly journals Comparison of Protein A Gene Sequencing with Pulsed-Field Gel Electrophoresis and Epidemiologic Data for Molecular Typing of Methicillin-Resistant Staphylococcus aureus

2000 ◽  
Vol 38 (4) ◽  
pp. 1347-1351 ◽  
Author(s):  
Yi-Wei Tang ◽  
Michael G. Waddington ◽  
Douglas H. Smith ◽  
Janice M. Manahan ◽  
Peggy C. Kohner ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Sequence Analysis ◽  
Molecular Typing ◽  
Gel Electrophoresis ◽  
Protein A ◽  
Pulsed Field Gel Electrophoresis ◽  
Sequencing Analysis ◽  
Methicillin Resistant ◽  
Pulsed Field ◽  
Epidemic Period

The epidemiologic relatedness of methicillin-resistantStaphylococcus aureus (MRSA) isolates is currently determined by analysis of chromosomal DNA restriction patterns by pulsed-field gel electrophoresis (PFGE). We have evaluated an alternative typing system (MicroSeq StaphTrack Kit; Perkin-Elmer Biosystems) based on the sequence analysis of the chromosomally encoded polymorphic repeat X region of the S. aureus protein A (spa) gene. A total of 69 clinical MRSA isolates were divided into 18 groups according to the number and nucleotide sequences of the spa repeats. Molecular typing results obtained both by spa sequencing and from the PFGE patterns were concordant except for one group, which contained 20 isolates recovered over a 2-year period from hospitalized patients at the Mayo Clinic. Although the spa typing patterns were indistinguishable for those isolates, PFGE analysis yielded seven related but distinguishable patterns. Further coagulase gene sequence analysis subtyped those 20 strains into four groups which followed distinct temporal and geographic distributions. During a 2-year epidemic period there were up to 7 fragment changes in PFGE patterns among epidemiologically related isolates, suggesting that PFGE may be unsuitable for long-term typing of strains involved in epidemics. Although more limited than PFGE in discriminatory power, spa sequencing analysis could be used as a screening method for typing of MRSA strains because of the shorter turnaround time, ease of use, and the inherent advantages of sequence analysis, storage, and sharing of information.

scholarly journals Transposon Insertion Reveals pRM, a Plasmid of Rickettsia monacensis

2007 ◽  
Vol 73 (15) ◽  
pp. 4984-4995 ◽  
Author(s):  
Gerald D. Baldridge ◽  
Nicole Y. Burkhardt ◽  
Roderick F. Felsheim ◽  
Timothy J. Kurtti ◽  
Ulrike G. Munderloh
Keyword(s):  
Southern Blot ◽  
Gel Electrophoresis ◽  
Fluorescent Protein ◽  
Pulsed Field Gel Electrophoresis ◽  
Marker Genes ◽  
Rickettsia Felis ◽  
Pulsed Field ◽  
Rickettsia Monacensis ◽  
Obligate Intracellular Bacteria ◽  
Green Fluorescent

ABSTRACT Until the recent discovery of pRF in Rickettsia felis, the obligate intracellular bacteria of the genus Rickettsia (Rickettsiales: Rickettsiaceae) were thought not to possess plasmids. We describe pRM, a plasmid from Rickettsia monacensis, which was detected by pulsed-field gel electrophoresis and Southern blot analyses of DNA from two independent R. monacensis populations transformed by transposon-mediated insertion of coupled green fluorescent protein and chloramphenicol acetyltransferase marker genes into pRM. Two-dimensional electrophoresis showed that pRM was present in rickettsial cells as circular and linear isomers. The 23,486-nucleotide (31.8% G/C) pRM plasmid was cloned from the transformant populations by chloramphenicol marker rescue of restriction enzyme-digested transformant DNA fragments and PCR using primers derived from sequences of overlapping restriction fragments. The plasmid was sequenced. Based on BLAST searches of the GenBank database, pRM contained 23 predicted genes or pseudogenes and was remarkably similar to the larger pRF plasmid. Two of the 23 genes were unique to pRM and pRF among sequenced rickettsial genomes, and 4 of the genes shared by pRM and pRF were otherwise found only on chromosomes of R. felis or the ancestral group rickettsiae R. bellii and R. canadensis. We obtained pulsed-field gel electrophoresis and Southern blot evidence for a plasmid in R. amblyommii isolate WB-8-2 that contained genes conserved between pRM and pRF. The pRM plasmid may provide a basis for the development of a rickettsial transformation vector.

scholarly journals Prevalence and Characterization of Extended-Spectrum Beta-Lactamase-Producing Enterobacteriaceae Isolated in Canadian Hospitals: Results from CANWARD 2007

2009 ◽  
Vol 20 (suppl a) ◽  
pp. 43A-48A ◽  
Author(s):  
Patricia J Baudry ◽  
Melissa McCracken ◽  
Philippe Lagacé-Wiens ◽  
Michael R Mulvey ◽  
George G Zhanel ◽  
...  
Keyword(s):  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Diffusion Method ◽  
Beta Lactamase ◽  
Single Strain ◽  
Pulsed Field ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Extended Spectrum ◽  
Esbl Producers

OBJECTIVE: The purpose of the present study was to determine the prevalence and molecular epidemiology of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae identified from Canadian hospitals in 2007. METHODS: Clinically significant isolates were collected as part of the Canadian Ward Surveillance Study (CANWARD 2007) from January to December 2007, inclusive, from 12 sentinel hospital centres across Canada. Minimum inhibitory concentrations were determined by broth microdilution, and putative ESBL isolates were confirmed by the Clinical and Laboratory Standards Institute disk diffusion method. Polymerase chain reaction and DNA sequencing were used to detectblaSHV,blaTEM,blaCTX-MandblaOXA-likegenes. Strains were typed using pulsed-field gel electrophoresis. RESULTS: A total of 3.4% and 1.6% ofEscherichia coliandKlebsiella pneumoniae, respectively, were identified as ESBL producers. Resistance to fluoroquinolones, doxycycline, trimethoprim/sulfamethoxazole and gentamicin occurred in 92.5% and 71.4%, 75.5% and 71.4%, 67.9% and 57.1%, and 58.5% and 57.1% of ESBL-producingE coliandK pneumoniae, respectively. A total of 90.6% and 71.4% of ESBL-producingE coliandK pneumoniaewere identified as multidrug resistant. The CTX-M type was the predominant ESBL, with CTX-M-15 as the predominant genotype. A total of 81.7% ESBL-producers carried several beta-lactamase genes. Pulsed-field gel electrophoresis revealed that the majority of ESBL producers were not genetically related (less than 80% homology). Similar patient demographics were observed among both ESBL-producingE coliand K pneumoniae. CONCLUSION: CTX-M has become the most common enzyme among both ESBL-producingE coliandK pneumoniae. The spread of ESBLproducing bacteria across Canada is polyclonal and is not due to the clonal spread of a single strain.

scholarly journals Application of an Optimized and Highly Discriminatory Method Based on Arbitrarily Primed PCR for Epidemiologic Analysis of Methicillin-Resistant Staphylococcus aureusNosocomial Infections

1998 ◽  
Vol 36 (4) ◽  
pp. 1128-1134 ◽  
Author(s):  
Antonio Olmos ◽  
Juan J. Camarena ◽  
José M. Nogueira ◽  
Juan C. Navarro ◽  
Julia Risen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Gel Electrophoresis ◽  
Pulsed Field Gel Electrophoresis ◽  
Methicillin Resistant ◽  
Pulsed Field ◽  
Main Cluster ◽  
Pcr Method ◽  
Arbitrarily Primed Pcr ◽  
Epidemiologic Analysis

The optimization of an arbitrarily primed PCR method for typing 96 methicillin-resistant Staphylococcus aureus (MRSA) isolates was compared with pulsed-field gel electrophoresis. Identical results in the differentiation of MRSA clones and identification of the main cluster that included 82 strains (88% of patients) were obtained by both techniques.

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