Suchergebnisse

Antibiotic resistance forms a serious threat to the health of hospitalised patients, rendering otherwise treatable bacterial infections potentially life-threatening. A thorough understanding of the mechanisms by which resistance spreads between patients in different hospitals is required in order to design effective control strategies. We measured the differences between bacterial populations of 52 hospitals in the United Kingdom and Ireland, using whole genome sequences from 1085 MRSA clonal complex 22 isolates collected between 1998 and 2012. The genetic differences between bacterial populations were compared with the number of transferred patients between hospitals and their regional structure. The MRSA populations within single hospitals, regions, and countries were genetically distinct from the rest of the bacterial population at each of these levels. Hospitals from the same patient referral regions showed more similar MRSA populations, as did hospitals sharing many patients. Furthermore, the bacterial population from different time-periods within the same hospital were generally more similar to each other than contemporaneous bacterial populations from different hospitals. We conclude that, while a large part of the dispersal and expansion of MRSA takes place among patients seeking care in single hospitals, inter-hospital spread of resistant bacteria is by no means a rare occurrence. Hospitals are exposed to constant introductions of MRSA on a number of levels: 1) most MRSA is received from hospitals that directly transfer large numbers of patients, while 2) fewer introductions happen between regions or 3) across national borders, reflecting lower numbers of transferred patients. A joint coordinated control effort between hospitals, is therefore paramount for the national control of MRSA, antibiotic-resistant bacteria, and other hospital-associated pathogens. ; This work was supported by grants from the UKCRC Translational Infection Research Initiative, and the Medical Research Council (Grant Number G1000803) with contributions to the Grant from the Biotechnology and Biological Sciences Research Council, the National Institute for Health Research on behalf of the Department of Health, and the Chief Scientist Office of the Scottish Government Health Directorate (to SJP); and by Wellcome Trust grant number 098051 and 089472 awarded to the Wellcome Trust Sanger Institute and BGS respectively. MET is a Clinician Scientist Fellow, supported by the Academy of Medical Sciences and The Health Foundation, and by the NIHR Cambridge Biomedical Research Centre. We thank the British Society of Antimicrobial Chemotherapy (BSAC) bacteraemia resistance surveillance programme for supplying bacterial isolates.

This study was supported by grants from the UKCRC Translational Infection Research Initiative and the Medical Research Council [grant no. G1000803] with contributions to the grant from the Biotechnology and Biological Sciences Research Council, the National Institute for Health Research on behalf of the Department of Health, and the Chief Scientist Office of the Scottish Government Health Directorate (to Prof. Peacock); by the Wellcome Trust [grant no. 098051 awarded to the Wellcome Trust Sanger Institute]; by the Health Protection Agency (to Prof. Peacock); and by the NIHR Cambridge Biomedical Research Centre (to Dr Török and Prof. Peacock). EMT is a Clinician Scientist Fellow funded by the Academy of Medical Sciences and the Health Foundation. ; Fusidic acid is a topical and systemic antimicrobial used for the treatment of staphylococcal infections in hospitals and the community. Sales of fusidic acid and resistance rates among meticillin-resistant Staphylococcus aureus (MRSA) doubled between 1990 and 2001. For the following decade, fusidic acid resistance rates among isolates from Addenbrooke's Hospital (Cambridge, UK) were compared with national resistance rates from MRSA bacteraemia surveillance data and with antimicrobial sales data. Sales of fusidic acid remained relatively constant between 2002 and 2012, whilst fusidic acid resistance increased two- and four-fold in MRSA bacteraemias nationally and in MRSA isolates from Cambridge, respectively. A subgroup of MRSA resistant only to fusidic acid increased after 2006 by 5-fold amongst bacteraemias nationally and 17-fold (to 7.7% in 2012) amongst Cambridge MRSA isolates. All of the available local isolates from 2011 to 2012 (n = 23) were acquired in the community, were not related epidemiologically and belonged to multilocus sequence typing (MLST) groups ST1, 5, 8, 45 or 149 as revealed from analysis of whole-genome sequence data. All harboured the fusC gene on one of six distinct staphylococcal cassette chromosome (SCC) elements, four of which were dual-resistance chimeras that encoded β-lactam and fusidic acid resistance. In summary, fusidic acid-resistant MRSA increased in prevalence during the 2000s with notable rises after 2006. The development of chimeric cassettes that confer dual resistance to β-lactams and fusidic acid demonstrates that the genetics underpinning resistance in community-associated MRSA are evolving. ; Publisher PDF ; Peer reviewed

Different diagnostic parameters may affect the tropism prediction reliability. The impact of usage of FPR cut‐offs<20%, use of viral RNA versus proviral DNA samples, single versus triple amplification, and presence of MVC resistance mutations on tropism prediction at baseline were analysed on 101 patients receiving maraviroc (MVC) and correlated with their clinical outcome. This was a non‐interventional, retrospective study. 82 RNA and 54 DNA samples from the 101 patients receiving MVC were obtained. The V3 region was sequenced and the tropism predicted using the geno2pheno[coreceptor] and T‐CUP tools with FPR cut‐offs of 5%, 7.5%, 10%, 15% and 20%. Additionally, 27/82 RNA and 28/54 DNA samples were analysed in triplicate and 34/82 samples with the ESTA assay. The influence of 16 MVC resistance mutations on clinical outcome was studied. The genotypic susceptibility score (GSS) of the concomitant drugs was mapped to numerical values: susceptible to 1 (or 0.5 for NRTIs), intermediate to 0.5 (0.25 for NRTIs) and resistant to 0. Detection of baseline R5 viruses in RNA (by geno2pheno[coreceptor] and T‐CUP) or DNA (by T‐CUP) samples correlated with MVC‐treatment success. Both tools performed very similarly, with PPVs close to 90%, even with FPR cut‐offs as low as 5%. The use of triple amplification did not improve the prediction value but reduced the number of patients elegible for MVC treatment. No influence of the GSS or MVC resistance mutations on the clinical outcome was detected. Genotypic tropism testing from viral RNA and proviral DNA using the geno2pheno[coreceptor] and T‐CUP systems is valid to select candidates for MVC treatment. Our data suggest that the use of FPR cut‐offs of 5–7.5% and single amplification from RNA or DNA would assure a safe administration of MVC without excluding many patients who could benefit from this potent antiretroviral drug.