The current MLVA typing scheme for is less discriminatory than MLST and PFGE for epidemic-virulent, hospital-adapted clonal types-1

<p><b>Copyright information:</b></p><p>Taken from "The current MLVA typing scheme for is less discriminatory than MLST and PFGE for epidemic-virulent, hospital-adapted clonal types"</p><p>http://www.biomedcentral.com/1471-2180/7/28</p><p>BMC Microbiology 2007;7():28-28.</p><p>Published online 10 Apr 2007</p><p>PMCID:PMC1865547.</p><p></p> ST for several MTs (b), respectively. Each line separates MLVA/MLST types differing by a single locus (single locus variants). ST-64 is not part of the given collection and was included for a better illustration of relatedness between MLST types. The MLVA type of ST-64 is not known

Pre-Use Susceptibility to Ceftaroline in Clinical <i>Staphylococcus aureus</i> Isolates from Germany: Is There a Non-Susceptible Pool to be Selected?

<div><p>Ceftaroline is a new cephalosporin active against Methicillin-resistant <i>Staphylococcus aureus</i> (MRSA). Based on a representative collection of clinical <i>S</i>. <i>aureus</i> isolates from Germany, supplemented with isolates of clonal lineages ST228 and ST239, we demonstrate the in-vitro susceptibility towards ceftaroline prior to its introduction into clinical use for a total of 219 isolates. Susceptibility testing was performed by broth microdilution, disc diffusion and Etest, respectively. Results were interpreted according to EUCAST guidelines and showed considerable variance in dependence on clonal affiliation of the isolates tested. Among isolates of widespread hospital-associated lineages we found a high proportion of clinical isolates with MICs close to the EUCAST breakpoint (MIC_50/90 1.0/1.5 mg/L); currently, interpretation of these “borderline” MICs is complicated by a lack of concordant susceptibility testing methods and reasonable breakpoint determination. Isolates of clonal lineages ST228 and ST239 demonstrated increased MIC_50/90 values of 2.5/3.33 mg/L. Sequencing of <i>mecA</i> revealed no association of resistance to a specific mecA polymorphism, but rather reveals two regions in the non-penicillin-binding domain of PbP2a which displayed different combinations of mutations putatively involved in resistance development. This study provides national baseline data to (i) adjust susceptibility testing methods and current breakpoints to clinical and epidemiological requirements, (ii) evaluate current breakpoints with respect to therapeutic outcome and (iii) monitor further resistance evolution.</p></div

Comparative results of ceftaroline susceptibility testing for 219 <i>S</i>. <i>aureus</i> isolates described in this study using different test methodologies.

<p>Grey bars: agar diffusion, CPT discs (5 μg); black squares: CPT MICs determined by Etest; red circles: CPT MICs determined by BMD; The sizes of squares and circles denotes the number of isolates with the respective inhibitory zone/MIC combination.</p

CPT susceptibility testing in different study populations using different methodologies and 2013 vs. 2014 EUCAST interpretation.

<p>CPT susceptibility testing in different study populations using different methodologies and 2013 vs. 2014 EUCAST interpretation.</p

Strains used in this study.

<p>Strains used in this study.</p

Determination of plasmid content and localization of the <i>cfr(B)</i> variant in the five <i>E</i>. <i>faecium</i> isolates.

<p>(A) Separation of whole and linearized plasmid content by S1-PFGE. (B) Hybridization using a <i>cfr</i>-specific probe was carried out after transfer of plasmids to a nitrocellulose membrane. The asterisks indicate a <i>cfr</i>-positive signal (in B) and the corresponding plasmid (in A). <i>S</i>. <i>aureus</i> 8325was used as a reference strain for estimation of plasmid sizes.</p

Maximum likelihood analysis of German <i>cfr(B)</i>-positive <i>E</i>. <i>faecium</i>.

<p>hylogenetic analysis inferred from mapping of whole genome sequencing reads to reference genome <i>E</i>. <i>faecium</i> 64/3 (CP012522) did not indicate a close relationship between the German <i>E</i>. <i>faecium</i> isolates. For comparative reasons, the length of the putative transposon Tn<i>6218</i> sequence is indicated by boxes. Strain characteristics such as year and federal state of isolation as well as sequence types are listed. Abbreviations: NRW, North Rhine-Westphalia; SA, Saxony-Anhalt; BW, Baden-Wuerttemberg; SLV, single locus variant.</p

Schematic representation of Tn<i>6218</i> in clinical <i>E</i>. <i>faecium</i> isolates.

<p>Different variants of Tn<i>6218</i>-like elements were detected in the five German <i>cfr(B)</i>-positive <i>E</i>. <i>faecium</i> clinical isolates (UW numbering). UW12712 exhibits a truncated element encoding solely for the <i>cfr(B)</i> variant and a hypothetical protein of the original composite transposon Tn<i>6218</i> of <i>C</i>. <i>difficile</i> (HG002389). <i>E</i>. <i>faecium</i> UW10882, UW11590 and UW11733 all harbor highly similar or even complete identical (UW11590 and UW11733) Tn<i>6218</i>-like structures and gene contents. A comparison of Tn<i>6218</i> of the clinical isolates and of <i>C</i>. <i>difficile</i> Ox3196 to the mobile element of the American <i>E</i>. <i>faecium</i> isolate 448-18961R (KR610408) revealed an almost entirely different gene composition. Numbers represent the length of the published sequence or obtained contig, respectively. Abbreviations: int, integrase; xis, excisionase; rep, putative topoisomerase; HTH Xre, putative transcriptional regulator; i, integrase core domain fragment; h and hypo, hypothetical protein; sigma 70, sigma 70 region 4; H, HTH motif coding sequence (CDS); C, CD31680 CDS; r, regulatory protein.</p

Whole genome comparison of <i>C</i>. <i>difficile</i> Ox3196 and Ox3206.

<p>BRIG alignment of the concatenated genomic contigs obtained by WGS revealed two regions which are absent in <i>C</i>. <i>difficile</i> Ox3206 and harbor Tn<i>916</i>-like related genes. Likewise, the entire transposon Tn<i>6218</i> (red), containing the <i>cfr</i> resistance locus, is present in <i>C</i>. <i>difficile</i> Ox3196 only.</p

Insertion sites of the Tn<i>6218</i>-like element in clinical <i>E</i>. <i>faecium</i> isolates.

<p>Insertion sites of the Tn<i>6218</i>-like element in clinical <i>E</i>. <i>faecium</i> isolates.</p