1,720,972 research outputs found
Use of a LightCycler gyrA mutation assay for identification of ciprofloxacin-resistant Campylobacter coli
No full textA fluorescence resonance energy transfer-based assay has been employed to detect mutations at the 86 codon in the DNA gyrase A (gyrA) gene in Campylobacter coli strains. These mutations were associated with ciprofloxacin resistance in strains isolated in Italy in 2000. The mutations in the gyrA gene were detected by real-time PCR amplification followed by hybridization with two fluorescent probes designed with sequences complementary to the wild-type C. coli gyrA gene. Mutation detection was performed by melting peak analysis of the probe-PCR product hybrid performed on a LightCycler (Roche Diagnostic). This gyrA mutation assay allows a rapid and reproducible screening method of ciprofloxacin-resistant C. coli strains. © 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved
Identification of ciprofloxacin-resistant Campylobacter jejuni and analysis of the gyrA gene by the LightCycler mutation assay
No full textA real-time PCR assay was developed to identify ciprofloxacin-resistant Campylobacter jejuni. Ciprofloxacin resistance in C. jejuni has been associated with a C→T nucleotide point mutation occurring at the 86 codon of the gyrA gene. Other nucleotide substitutions have been identified in proximity to or at the same codon in the gyrA gene, but their role in ciprofloxacin resistance is still unknown. The LightCycler assay is based on the fluorescence resonance energy transfer technology using melting peak analysis of two fluorescent probes hybridized on PCR amplicons. This assay was used to detect the 86-codon mutation conferring ciprofloxacin resistance, as well as other nucleotides substitutions occurring within the same site in the gyrA gene. This gyrA mutation assay allows a rapid and reproducible screening method of ciprofloxacin resistant strains and was applied to C. jejuni strains isolated in Italy in 2000. © 2004 Elsevier Ltd. All rights reserved
Molecular epidemiology and origin of cholera reemergence in Italy and Albania in the 1990s
No full textIn 1994 a cholera epidemic occurred in Italy and Albania after more than a decade of case absence. To investigate genotypic characteristics and
the origin of the epidemic strains, 110 Vibrio cholerae O1 El Tor isolates from Italy and Albania were studied by randomly amplified polymorphic
DNA analysis (RAPD), BglI ribotyping, and pulsed-field gel electrophoresis (PFGE) of genomic DNA. The Italian and Albanian strains were all
ribotype 6 and their RAPD and PFGE patterns were identical as well. These findings indicated that the 1994 isolates belonged to the same clone
and that the clone was part of the larger global spread of epidemic ribotype 6 strains, which started in southern Asia in 1990
Molecular genotyping of Salmonella enterica Abortusovis by pulsed field gel electrophoresis
No full textGenotyping of Salmonella strains is an important tool to discriminate among isolates and to improve epidemiological studies when an outbreak occurs. No phagetyping scheme is available for Salmonella enterica subsp. enterica serovar Abortusovis (SAO) and molecular methods previously used were not standardized and were time consuming. Among the DNA-based methods of genotyping, pulsed field gel electrophoresis (PFGE) is currently in use to subtype Salmonella isolates. In this study we evaluated the feasibility of genotyping of SAO by XbaI and BlnI restrictions. Separation of restricted fragments was performed by PFGE. To test the possibility to apply this methodology to epidemiological investigation, a collection of 38 SAO strains isolated in different regions of Italy were analyzed. Eighteen and 29 different PFGE profiles were defined for XbaI and BlnI digestions, respectively. The method demonstrated an adequate typing ability and an excellent discriminatory power. Results from this study show that PFGE may represent a powerful tool to discriminate within the SAO serovar, and provide useful information in support of traditional epidemiological investigations. In particular, this method could be used to identify the origin of infection during outbreaks within a single flock or in different herds. © 2006 Elsevier B.V. All rights reserved
Antibiotic resistance conferred by a conjugative plasmid and a class I integron in Vibrio cholerae O1 El Tor strains isolated in Albania and Italy
No full textMultidrug-resistant Vibrio cholerae O1 El Tor strains isolated during the 1994 outbreak of cholera in Albania and Italy were characterized for the molecular basis of antibiotic resistance. All strains were found to be resistant to tetracycline, streptomycin, spectinomycin, trimethoprim, sulfathiazole, and the vibriostatic compound O/129 (2,4-diamino-6,7- diisopropylteridine). Resistance genes were self-transferable by a conjugative plasmid of about 60 MDa, with the exception of spectinomycin resistance, which was conferred by the aadA1 gene cassette located in the bacterial chromosome within a class 1 integron. The resistance to trimethoprim and O/129 was conferred by the dfrA1 gene, which was present on the plasmid. Although the dfrA1 gene is known to be borne on an integron cassette, class 1, 2, or 3 intI genes were not detected as part of the plasmid DNA from the strains studied
Class 1 integron-borne multiple-antibiotic resistance carried by IncFI and IncL/M plasmids in Salmonella enterica serotype typhimurium
No full textThe presence and genetic content of integrons were investigated for 37 epidemiologically unrelated multiple-drug-resistant strains of Salmonella enterica serotype Typhimurium from humans. All isolates were resistant to ampicillin, chloramphenicol, kanamycin, streptomycin, sulfonamides, and trimethoprim, as well as to tetracycline and/or nalidixic acid; 20% of them were also resistant to gentamicin and amikacin. Three different class 1 integrons (In-t1, In-t2, and In-t3) were identified by Southern blot hybridization, PCR, and DNA sequencing, and these integrons were found to carry the aadB, catB3, oxa1, aadA1a, aacA4, and aacC1 gene cassettes. Integrons In-t1 (aadB and catB3) and In-t2 (oxa1 and aadA1a) were both located on a conjugative IncFI plasmid of 140 kb. In-t3 (aacA4, aacC1, and aadA1a) was located on an IncL/M plasmid of 100 kb which was present, in association with the IncFI plasmid, in gentamicin- and amikacin-resistant isolates. Despite the extensive similarity at the level of the antibiotic resistance phenotype, integrons were not found on the prototypic IncFI plasmids carried by epidemic Salmonella strains isolated during the late 1970s. The recent appearance and the coexistence of multiple integrons on two conjugative plasmids in the same Salmonella isolate are examples of how mobile gene cassettes may contribute to the acquisition and dissemination of antibiotic resistance
Molecular characterization and antibiotic resistance of salmonella serovars isolated in the Apulia region of Italy
No full textDuring the period January 2013 December 2015, 175 cases of human salmonellosis were reported in the Apulia Region of Italy.
The aim of this study was to characterize Salmonelle strains from the standpoint of serovars prevalence,antimicrobial resistance and clonal origin. All the strains were tested by pulsed-field gel electrophoresis ( PFGE) according to the PulseNet Protocol and cluster analysis was performed using BioNumerics Software. Molecular typing by PFGE yelded 60 different macrorestriction profiles among 33 serotypes
Phenotypic and genetic traits of Salmonella enterica subsp. serovar Typhimurium strains causing salmonellosis foci in rabbit farms from Southern Italy in 1999-2003.
No full textIn this study, we characterised the Salmonella Typhimurium strains responsible for four outbreaks which
occurred in distinct rabbit farms (Southern Italy) from 1999 to 2003. Strains were typed by Pulsed Field
Gel Electrophoresis (PFGE) and the genetic basis of antimicrobial resistance was established. A major
group of clonally related isolates, pulsotype STYMXB.0061, accounted for three of the salmonellosis foci.
Strains were resistant to streptomycin, chloramphenicol, tetracycline, ampicillin and sulphonamides
encoded respectively by the aadA2, floR, tetG, blaPSE-1, sul1 gene cluster harboured by a Salmonella Genomic
Island 1. The clonally related group of isolates included strains phage type DT104, DT12 or undefined
type (NT). The fourth salmonellosis focus was caused by a strain pulsotype STYMXB.0147, resistant to sulphonamides
(encoded by sul2) and phage type U302. Results provided first molecular characterisation of
S. Typhimurium strains isolated from rabbit farms in Italy and highlighted the presence of the pulsotype
STYMXB.0061 even before its wide detection among human clinical isolates collected in Italy in the mid
2000s from clinical case
- …
