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Typing

About: Typing is a research topic. Over the lifetime, 5010 publications have been published within this topic receiving 146539 citations.


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Journal ArticleDOI
TL;DR: PCR-based replicon typing, linked to the detection of other important plasmid-encoded traits, seems to be a feasible tool for tracing disseminating resistance plasmids stably maintained in various environments.
Abstract: A PCR-based typing scheme was applied to identify plasmids in an epidemiologically and geographically diverse strain collection of Enterococcus faecium (n=93). Replicon types of pRE25 (n=56), pRUM (n=41), pIP501 (n=17) and pHTbeta (n=14) were observed in 83% of the strains, while pS86, pCF10, pAM373, pMBB1 or pEF418 were not detected. Furthermore, 61% of the strains contained the axe-txe (n=42) or/and the omega-epsilon-zeta (n=18) plasmid stabilization loci. Sequence analyses divided the omega-epsilon-zeta operon into two distinct phylogenetic groups. The present typing scheme accounted for about 60% of the total number of plasmids detected by S1 nuclease analyses, which revealed zero to seven plasmids (10 kb to >200 kb) per isolate. Interestingly, strains belonging to the clinically important clonal complex 17 (CC17) yielded a significantly higher number of plasmids (3.1) and pRUM replicons (74%) than non-CC17 strains (2.2% and 35%, respectively). A prevalent genetic linkage between the pRUM-replicon type and axe-txe was demonstrated by cohybridization analyses. The vanA resistance determinant was associated with all four replicon types, but we also confirmed the genetic linkage of vanA to unknown transferable replicons. PCR-based replicon typing, linked to the detection of other important plasmid-encoded traits, seems to be a feasible tool for tracing disseminating resistance plasmids stably maintained in various environments.

112 citations

Journal ArticleDOI
TL;DR: The results suggest that the genetic heterogeneity of B. henselae strains is high, providing tools for epidemiological and clinical follow-up studies, and entryobacterial repetitive intergenic consensus (ERIC)-PCR, repetitive extragenic palindromic (REP) PCR, and arbitrarily primed (AP-PCR) methods were found useful for typing.
Abstract: Seventeen isolates of Bartonella henselae from the region of Freiburg, Germany, obtained from blood cultures of domestic cats, were examined for their genetic heterogeneity. On the basis of different DNA fingerprinting methods, including pulsed-field gel electrophoresis (PFGE), enterobacterial repetitive intergenic consensus (ERIC)-PCR, repetitive extragenic palindromic (REP) PCR, and arbitrarily primed (AP)-PCR, three different variants were identified among the isolates (variants I to III). Variant I included 6 strains, variant II included 10 strains, and variant III included only one strain. By all methods used, the isolates could be clearly distinguished from the type strain, Houston-1, which was designated variant IV. A previously published type-specific amplification of 16S rDNA differentiated two types of the B. henselae isolates (16S rRNA types 1 and 2). The majority of the isolates (16 of 17), including all variants I and II, were 16S rRNA type 2. Only one isolate (variant III) and the Houston-1 strain (variant IV) comprised the 16S rRNA type 1. Comparison of the 16S rDNA sequences from one representative strain from each of the three variants (I to III) confirmed the results obtained by 16S rRNA type-specific PCR. The sequences from variant I and variant II were identical, whereas the sequence of variant III differed in three positions. All methods applied in this study allowed subtyping of the isolates. PFGE and ERIC-PCR provided the highest discriminatory potential for subtyping B. henselae strains, whereas AP-PCR with the M13 primer showed a very clear differentiation between the four variants. Our results suggest that the genetic heterogeneity of B. henselae strains is high. The methods applied were found useful for typing B. henselae isolates, providing tools for epidemiological and clinical follow-up studies.

111 citations

Journal ArticleDOI
TL;DR: In this paper, the authors attribute Panton-Valentine leucocidin (PVL)-positive methicillin-resistant Staphylococcus aureus (MRSA) to clonal lineages by molecular typing with special reference to isolates exhibiting spa type t008/multilocus sequence type (MLST) ST8 [widely disseminated in the USA as ‘community-associated MRSA (caMRSA), USA300’].
Abstract: Objectives: The aim of this paper is to attribute Panton-Valentine leucocidin (PVL)-positive methicillinresistant Staphylococcus aureus (MRSA) to clonal lineages by molecular typing with special reference to isolates exhibiting spa type t008/multilocus sequence type (MLST) ST8 [widely disseminated in the USA as ‘community-associated MRSA (caMRSA) USA300’]. Methods :P VL-positive MRSA (n 5 117) were detected among 4815 MRSA sent to the German National Reference Laboratory for typing. These isolates were analysed by PFGE, spa typing, multilocus sequence typing, grouping of SCCmec elements and PCR detection of arcA, msr(A), mph(B) and the � 6 AT repeat unit in the SACOL0058 sequence. Results: Among the 117 isolates, 80 exhibited spa type t044 (corresponding to MLST ST80) and 23 exhibited spa type t008/MLST ST8. Other spa types were sporadically represented. Further characterization of isolates exhibiting t008/ST8 by PCR [arcA, msr(A), mph(B), � 6 AT repeat signature] indicates the arrival of caMRSA ‘USA300’ in Central Europe. Conclusions: caMRSA ST80 still predominate; however, caMRSA ST8 exhibiting the characteristics of the ‘USA300’ clone became the second most frequent. Routine detection of this clone in clinical bacteriology can be easily performed by PCR.

111 citations

Journal ArticleDOI
TL;DR: In this article, an extended multilocus sequencing approach was used to examine the molecular diversity of 118 S. aureus isolates recovered from a range of host species and to compare these data with the known diversity of human-derived isolates.
Abstract: Staphylococcus aureus is an important pathogen of man, but is also able to colonize and cause disease in a wide variety of mammals and birds. An extended multilocus sequencing approach, involving multilocus sequence typing (MLST), sas typing, spa typing and agr typing, was used to examine the molecular diversity of 118 S. aureus isolates recovered from a range of host species and to compare these data with the known diversity of human-derived isolates. MLST revealed that the commonest animal-associated MLST types were ST133, ST5, ST71, ST97, ST126 and ST151. ST133 appears to be an ungulate-animal-specific genotype, as no evidence of ST133 associating with humans has yet been found in the literature. Novel and unique sas alleles were identified in the animal-associated strains that may represent animal-associated sas alleles. However, sas typing exhibited a lower typeability than MLST for the animal strains (91.3 %). Phylogenetic analyses using neighbour-joining and maximum-parsimony trees localized ruminant-associated MLST lineages to both previously identified S. aureus subspecies aureus subgroups, thus explaining the finding of all four agr types within the ruminant-associated strains. S. aureus isolates recovered from chickens and rabbits were genotypically more similar to known human genotypes than the ruminant-associated lineages.

110 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023329
2022690
2021145
2020126
2019136
2018147