RESUMO
Whole-genome sequencing (WGS) makes it possible to determine the relatedness of bacterial isolates at a high resolution, thereby helping to characterize outbreaks. However, for Staphylococcus aureus, the accumulation of within-host diversity during carriage might limit the interpretation of sequencing data. In this study, we hypothesized the converse, namely, that within-host diversity can in fact be exploited to reveal the involvement of long-term carriers (LTCs) in outbreaks. We analyzed WGS data from 20 historical outbreaks and applied phylogenetic methods to assess genetic relatedness and to estimate the time to most recent common ancestor (TMRCA). The findings were compared with the routine investigation results and epidemiological evidence. Outbreaks with epidemiological evidence for an LTC source had a mean estimated TMRCA (adjusted for outbreak duration) of 243 days (95% highest posterior density interval [HPD], 143 to 343 days) compared with 55 days (95% HPD, 28 to 81 days) for outbreaks lacking epidemiological evidence for an LTC (P = 0.004). A threshold of 156 days predicted LTC involvement with a sensitivity of 0.875 and a specificity of 1. We also found 6/20 outbreaks included isolates with differing antimicrobial susceptibility profiles; however, these had only modestly increased pairwise diversity (mean 17.5 single nucleotide variants [SNVs] [95% confidence interval {CI}, 17.3 to 17.8]) compared with isolates with identical antibiograms (12.7 SNVs [95% CI, 12.5 to 12.8]) (P < 0.0001). Additionally, for 2 outbreaks, WGS identified 1 or more isolates that were genetically distinct despite having the outbreak pulsed-field gel electrophoresis (PFGE) pulsotype. The duration-adjusted TMRCA allowed the involvement of LTCs in outbreaks to be identified and could be used to decide whether screening for long-term carriage (e.g., in health care workers) is warranted. Requiring identical antibiograms to trigger investigation could miss important contributors to outbreaks.
Assuntos
Portador Sadio/epidemiologia , Surtos de Doenças , Tipagem Molecular , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/classificação , Staphylococcus aureus/genética , Sequenciamento Completo do Genoma , Adulto , Portador Sadio/microbiologia , Eletroforese em Gel de Campo Pulsado , Genótipo , Humanos , Testes de Sensibilidade Microbiana , Filogenia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificaçãoRESUMO
AIM: To determine the national practice of transvaginal ultrasound (TVUS) probe decontamination in English hospitals and to develop recommendations for guidance. MATERIALS AND METHODS: A literature review was undertaken to clarify best practice and evaluate methods of decontamination of TVUS probes. A questionnaire was developed to ascertain TVUS probe decontamination programmes in current use within English hospitals. This was sent to ultrasound leads of 100 English hospitals; 68 hospitals responded. RESULTS: There is a wide variation in TVUS probe decontamination across English hospitals. Although the majority of respondents (87%, 59/68) reported having clear and practical written guidelines for TVUS decontamination, the frequency, methods, and types of decontamination solutions utilized were widely variable and none meet the standards required to achieve high-level disinfection. CONCLUSION: While the decontamination of other endoluminal medical devices (e.g., flexible endoscopes) is well defined and regulated, the decontamination of TVUS probes has no such guidance. There appears to be incomplete understanding of the level of risk posed by TVUS probes, and in some cases, this has resulted in highly questionable practices regarding TVUS hygiene. There is an urgent need to develop evidence-based national guidance for TVUS probe decontamination.
Assuntos
Esterilização/estatística & dados numéricos , Ultrassonografia/normas , Vagina/diagnóstico por imagem , Inglaterra/epidemiologia , Feminino , Humanos , Guias de Prática Clínica como Assunto , Esterilização/métodos , Esterilização/normas , Inquéritos e Questionários , Ultrassonografia/métodos , Ultrassonografia/estatística & dados numéricosRESUMO
BACKGROUND: Intracavity medical devices (ICMDs) are used in a wide variety of healthcare settings. The approach to their decontamination and the resources available also differ widely. Their potential for infection transmission is considerable. AIM: To produce a comprehensive risk assessment-based approach to the decontamination of ICMDs, accompanied by an adaptable audit tool.
Assuntos
Descontaminação/métodos , Transmissão de Doença Infecciosa/prevenção & controle , Equipamentos e Provisões , Humanos , Sociedades CientíficasRESUMO
We report a significant reduction in the number of surgical site infections (SSIs) due to meticillin-resistant Staphylococcus aureus (MRSA) in patients undergoing cardiac surgery after the introduction of preoperative screening using a same-day polymerase chain reaction (PCR) test. This was an observational cohort study set in a cardiac surgery unit based in southwest England. We studied 1462 patients admitted for cardiac surgery between October 2004 and September 2006. The IDI MRSA PCR test was used preoperatively to screen 765 patients between October 2005 and September 2006. Patients identified as carriers were treated with nasal mupirocin ointment and topical triclosan for five days, with single-dose teicoplanin instead of flucloxacillin as perioperative antibiotic prophylaxis. The rate of SSI following cardiac surgery in this group was compared to 697 patients who underwent surgery without screening between October 2004 and September 2005. After introduction of PCR screening, the overall rate of SSI fell from 3.30% to 2.22% with a significant reduction in the rate of MRSA infections (relative risk reduction: 0.77; 95% confidence interval: 0.056-0.95). PCR screening combined with suppression of MRSA at the time of cardiac surgery is feasible in routine clinical practice and is associated with a significant reduction in subsequent MRSA SSIs.
Assuntos
Portador Sadio/diagnóstico , Infecção Hospitalar/prevenção & controle , Resistência a Meticilina , Reação em Cadeia da Polimerase , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/isolamento & purificação , Infecção da Ferida Cirúrgica/prevenção & controle , Cirurgia Torácica , Antibacterianos/uso terapêutico , Anti-Infecciosos Locais/uso terapêutico , Antibioticoprofilaxia , Estudos de Coortes , Infecção Hospitalar/epidemiologia , Inglaterra , Humanos , Programas de Rastreamento/métodos , Mupirocina/uso terapêutico , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética , Infecção da Ferida Cirúrgica/epidemiologia , Teicoplanina/uso terapêutico , Triclosan/uso terapêuticoRESUMO
Ventriculitis is an important complication following neurosurgery and is often associated with the use of an external ventricular drain (EVD). The incidence varies from <5% to 20%, partly due to variations in the definitions used for diagnosis. Staphylococci are the most important causes but the isolation of coagulase-negative staphylococci from a cerebrospinal fluid (CSF) sample needs to be interpreted with caution as it may represent contamination. Risk factors for ventriculitis include advanced age, the duration of EVD placement, the number of manipulations and the presence of intraventricular haemorrhage. Prevention strategies increasingly focus on the implementation of a care bundle that includes aseptic technique at the time of insertion and during any manipulations, skin preparation, prophylactic antibiotics, and appropriate dressings at the site of the EVD. The use of EVDs impregnated with antimicrobial agents is increasing but, whereas some studies show that these are effective, it is not clear whether they provide added benefit when there is compliance with other measures. Antimicrobial treatment is challenging as many widely used agents do not penetrate into the CSF and causative bacteria are increasingly multidrug resistant. Often a combination of high-dose intravenous and intraventricular agents is required, especially for Gram-negative infections. Large trials in this area are challenging to conduct; therefore, to better inform preventive strategies and to optimize management of this important condition, ongoing national surveillance and pooling of data on treatment approaches and outcomes are needed.
Assuntos
Ventriculite Cerebral/epidemiologia , Ventriculite Cerebral/prevenção & controle , Procedimentos Neurocirúrgicos/efeitos adversos , Infecção da Ferida Cirúrgica/epidemiologia , Infecção da Ferida Cirúrgica/prevenção & controle , Antibacterianos/uso terapêutico , Ventriculite Cerebral/diagnóstico , Ventriculite Cerebral/tratamento farmacológico , Drenagem/métodos , Humanos , Incidência , Fatores de Risco , Infecção da Ferida Cirúrgica/diagnóstico , Infecção da Ferida Cirúrgica/tratamento farmacológicoRESUMO
Analysis of the published genome sequences of Helicobacter pylori revealed that approximately 40% of the predicted open reading frames (ORFs) were of unknown function. We have developed the random mutagenesis and loop amplification (RMLA) strategy, and used this approach both to characterize individual virulence factors and to collectively screen comparatively large numbers of H. pylori mutants to identify genes that are not essential for viability in vitro. The mini-Tn3-Km transposon was used to generate a random mutant library in H. pylori strain G27. By screening the library of mutants we were able to demonstrate that the transposon integrated randomly into the chromosome of H. pylori and that RMLA was able to identify mutants in known virulence genes (urease and catalase). To test whether this strategy could be used as a high-throughput approach for the simultaneous identification of a series of nonessential genes of H. pylori, the transposon-chromosomal junctions of a pool of mutants were amplified by inverse PCR using circular fragments of genomic DNA obtained after chromosomal DNA extracted from the pool of mutants had been digested with HindIII and self-ligated. The amplification products were radioactively labelled and hybridized to a high density macroarray membrane containing a duplicated target sequence for every gene of H. pylori strain 26695. For the positive ORFs the precise site of transposon insertion was confirmed by PCR mapping. In total 78 H. pylori genes were unambiguously identified as nonessential for viability in vitro, including 20 with orthologues of unknown function in other species and 21 which were H. pylori-specific.
Assuntos
Genes Bacterianos , Helicobacter pylori/genética , Elementos de DNA Transponíveis , Biblioteca Gênica , Mutagênese , Reação em Cadeia da PolimeraseRESUMO
Although flagellar motility is essential for the colonisation of the stomach by Helicobacter pylori, little is known about the regulation of flagellar biosynthesis in this organism. We have identified a gene in H. pylori, designated fliI, whose deduced amino acid sequence revealed extensive homology with the FliI/LcrB/InvC family of proteins which energise the export of flagellar and other virulence factors in several bacterial species. An isogenic mutant of fliI was non-motile and synthesised reduced amounts of flagellin and hook protein subunits. The majority (> 99%) of mutant cells were completely aflagellate. These results suggest that FliI is a novel ATPase involved in flagellar export in H. pylori.
Assuntos
Adenosina Trifosfatases/fisiologia , Proteínas de Bactérias/fisiologia , Flagelos/metabolismo , Helicobacter pylori/enzimologia , Proteínas/fisiologia , ATPases Translocadoras de Prótons , Adenosina Trifosfatases/genética , Sequência de Aminoácidos , Proteínas de Bactérias/análise , Proteínas de Bactérias/genética , Flagelina/análise , Genes Bacterianos/genética , Helicobacter pylori/genética , Helicobacter pylori/ultraestrutura , Dados de Sequência Molecular , Mutação , Proteínas/genética , Análise de Sequência de DNA , Homologia de Sequência de AminoácidosRESUMO
In 1995, Haemophilus influenzae became the first free-living organism to have its entire genome sequence published. Since then, many similar projects have been started and, by the millennium, the genomes of a significant number of important human pathogens will have been sequenced. During this period of increasing access to microbial sequence data, parallel advances have occurred in techniques that allow the large-scale study of the entire genetic complement of micro-organisms. In the near future, these approaches will enable researchers to unravel further the complexity of microbial pathogenesis and identify new virulence determinants. Many of these will be suitable targets for development as diagnostic reagents, antimicrobial agents and vaccine candidates. Although it is difficult to predict the full impact that this almost overwhelming volume of information will have on the practice of microbiology, it is clear that it will result ultimately in new ways of diagnosing and combating infectious diseases.
Assuntos
Genoma , Técnicas Microbiológicas , Análise de Sequência de DNA/métodos , Bactérias/genética , Bactérias/patogenicidade , DNA Bacteriano/genética , DNA de Protozoário/genética , Bases de Dados Factuais , Genoma Bacteriano , Genoma de Protozoário , Humanos , Mutagênese , Análise de Sequência com Séries de Oligonucleotídeos , Virulência/genéticaRESUMO
BACKGROUND: Although surgical site infections (SSIs) are known to be associated with increased length of stay (LOS) and additional cost, their impact on the profitability of surgical procedures is unknown. AIM: To determine the clinical and economic burden of SSI over a two-year period and to predict the financial consequences of their elimination. METHODS: SSI surveillance and Patient Level Information and Costing System (PLICS) datasets for patients who underwent major surgical procedures at Plymouth Hospitals NHS Trust between April 2010 and March 2012 were consolidated. The main outcome measures were the attributable postoperative length of stay (LOS), cost, and impact on the margin differential (profitability) of SSI. A secondary outcome was the predicted financial consequence of eliminating all SSIs. FINDINGS: The median additional LOS attributable to SSI was 10 days [95% confidence interval (CI): 7-13 days] and a total of 4694 bed-days were lost over the two-year period. The median additional cost attributable to SSI was £5,239 (95% CI: 4,622-6,719) and the aggregate extra cost over the study period was £2,491,424. After calculating the opportunity cost of eliminating all SSIs that had occurred in the two-year period, the combined overall predicted financial benefit of doing so would have been only £694,007. For seven surgical categories, the hospital would have been financially worse off if it had successfully eliminated all SSIs. CONCLUSION: SSI causes significant clinical and economic burden. Nevertheless the current system of reimbursement provided a financial disincentive to their reduction.
Assuntos
Infecção Hospitalar/economia , Infecção Hospitalar/epidemiologia , Controle de Infecções/economia , Controle de Infecções/métodos , Infecção da Ferida Cirúrgica/economia , Infecção da Ferida Cirúrgica/epidemiologia , Custos e Análise de Custo , Infecção Hospitalar/prevenção & controle , Inglaterra/epidemiologia , Hospitais , Humanos , Tempo de Internação , Prevalência , Infecção da Ferida Cirúrgica/prevenção & controleRESUMO
BACKGROUND: In low- as well as in high-prevalence settings, healthcare workers (HCWs) may be a substantial, under-recognized, reservoir of meticillin-resistant Staphylococcus aureus (MRSA) and an important potential source of transmission to patients. AIM: To report an outbreak of MRSA in a cardiac surgery unit in England over a 10-month period. METHODS: Cases were defined as patients and staff on the cardiac surgery unit from whom the outbreak strain was newly isolated between 20 May 2011 and 16 March 2012. Representative isolates from all cases were characterized by spa-typing, pulsed-field gel electrophoresis and multi-locus variable-number tandem-repeat analysis (MLVA). FINDINGS: Four patients appeared to acquire MRSA during their inpatient stay on the cardiac surgery unit. All four patients and one HCW were found to be carrying an identical epidemic (E)MRSA-15 strain (spa t032, pulsotype A, MLVA profile 16-6-3-1-1-17-1-4). No other members of staff were found to be colonized with MRSA. The colonized HCW was thought to be the source of the outbreak and was decolonized using a combination of nasal mupirocin, chlorhexidine body wash and oral rifampicin and doxycycline. CONCLUSIONS: This report highlights recent changes in the epidemiology of MRSA in England and suggests an important role for colonized HCWs in the transmission of MRSA to patients. Screening HCWs may provide an increasingly valuable strategy in managing linked hospital acquisitions and well-defined outbreaks where initial investigation does not reveal a source.
Assuntos
Infecção Hospitalar/epidemiologia , Surtos de Doenças , Pessoal de Saúde , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Infecções Estafilocócicas/epidemiologia , Adulto , Idoso de 80 Anos ou mais , Serviço Hospitalar de Cardiologia , Infecção Hospitalar/microbiologia , Infecção Hospitalar/transmissão , Inglaterra/epidemiologia , Feminino , Genótipo , Humanos , Masculino , Staphylococcus aureus Resistente à Meticilina/classificação , Staphylococcus aureus Resistente à Meticilina/genética , Pessoa de Meia-Idade , Epidemiologia Molecular , Tipagem Molecular , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/transmissãoRESUMO
BACKGROUND: Outbreaks of norovirus can have a significant operational and financial impact on healthcare establishments. AIM: To assess whether containment of symptomatic patients in single rooms and bays at the beginning and end of norovirus outbreaks reduced the length of bed closure. METHODS: In 2007, we introduced a new strategy to limit the operational impact of hospital outbreaks of norovirus. Early in an outbreak, symptomatic patients were cohorted in single rooms or bays in an attempt to contain the outbreak without closing the entire ward. Once a ward had been closed, and as beds became available through discharges, patients were decanted into single rooms or empty bays with doors to facilitate earlier cleaning and opening of affected areas on the same ward. The impact of these changes was assessed by comparing outbreak data for two periods before and after implementation of the new strategy. FINDINGS: Prior to June 2007, 90% of outbreaks were managed by closure of an entire ward, compared with only 54% from June 2007 onwards. The duration of closure was significantly shorter for bays compared with entire wards, both before (3.5 vs 6, P = 0.0327) and after (3 vs 5, P < 0.0001) June 2007. When considering all outbreaks, there was a significant reduction in duration of closure after the change in strategy (6 vs 5, P = 0.007). CONCLUSION: Using ward compartmentalization to cohort affected patients at the beginning and end of norovirus outbreaks improved the efficiency of outbreak management and reduced operational disruption.
Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/prevenção & controle , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/prevenção & controle , Surtos de Doenças , Norovirus/isolamento & purificação , Isolamento de Pacientes/métodos , Pesquisa sobre Serviços de Saúde , Administração Hospitalar/métodos , HumanosAssuntos
Antibacterianos/efeitos adversos , Portador Sadio/diagnóstico , Portador Sadio/epidemiologia , Infecção Hospitalar/prevenção & controle , Desinfecção das Mãos , Instalações de Saúde/normas , Pessoal de Saúde , Controle de Infecções/métodos , Programas de Rastreamento/métodos , Resistência a Meticilina , Staphylococcus aureus Resistente à Meticilina/isolamento & purificação , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/patogenicidade , HumanosRESUMO
A detailed survey of 26 scientific journals showed that journal editors and a majority of authors of the re- c viewed papers seem unconcerned by the importance of correctly reporting their use of certified reference materials (CRMs). Only around 55% of the abstracts surveyed mention the use of CRMs described in these papers. This, however, is of key importance as the abstract of a paper is most widely available in electronic media. Many authors mentioned the use of CRMs in passing, often in incomplete form and without giving any details of the results obtained. Some are confused about the source of the reference material used, as they fail to report the type or the producer of CRMs applied. Others use materials that do not match the samples analyzed or do not see the need to use any CRM, despite the availability of suitable materials. Even in cases where correct data were given for type and producer of the CRMs, frequently the proper use and statistical evaluation are questionable. To improve this situation it is necessary that publishers should give recommendations where and how the use of CRMs should be described.