RESUMO
Some infectious diseases, including COVID-19, can undergo airborne transmission. This may happen at close proximity, but as time indoors increases, infections can occur in shared room air despite distancing. We propose two indicators of infection risk for this situation, that is, relative risk parameter (Hr) and risk parameter (H). They combine the key factors that control airborne disease transmission indoors: virus-containing aerosol generation rate, breathing flow rate, masking and its quality, ventilation and aerosol-removal rates, number of occupants, and duration of exposure. COVID-19 outbreaks show a clear trend that is consistent with airborne infection and enable recommendations to minimize transmission risk. Transmission in typical prepandemic indoor spaces is highly sensitive to mitigation efforts. Previous outbreaks of measles, influenza, and tuberculosis were also assessed. Measles outbreaks occur at much lower risk parameter values than COVID-19, while tuberculosis outbreaks are observed at higher risk parameter values. Because both diseases are accepted as airborne, the fact that COVID-19 is less contagious than measles does not rule out airborne transmission. It is important that future outbreak reports include information on masking, ventilation and aerosol-removal rates, number of occupants, and duration of exposure, to investigate airborne transmission.
Assuntos
Poluição do Ar em Ambientes Fechados , COVID-19 , Aerossóis , Surtos de Doenças , Humanos , SARS-CoV-2 , VentilaçãoRESUMO
BACKGROUND: There are still uncertainties in our knowledge of the amount of SARS-CoV-2 virus present in the environment - where it can be found, and potential exposure determinants - limiting our ability to effectively model and compare interventions for risk management. AIM: This study measured SARS-CoV-2 in three hospitals in Scotland on surfaces and in air, alongside ventilation and patient care activities. METHODS: Air sampling at 200 L/min for 20 min and surface sampling were performed in two wards designated to treat COVID-19-positive patients and two non-COVID-19 wards across three hospitals in November and December 2020. FINDINGS: Detectable samples of SARS-CoV-2 were found in COVID-19 treatment wards but not in non-COVID-19 wards. Most samples were below assay detection limits, but maximum concentrations reached 1.7×103 genomic copies/m3 in air and 1.9×104 copies per surface swab (3.2×102 copies/cm2 for surface loading). The estimated geometric mean air concentration (geometric standard deviation) across all hospitals was 0.41 (71) genomic copies/m3 and the corresponding values for surface contamination were 2.9 (29) copies/swab. SARS-CoV-2 RNA was found in non-patient areas (patient/visitor waiting rooms and personal protective equipment changing areas) associated with COVID-19 treatment wards. CONCLUSION: Non-patient areas of the hospital may pose risks for infection transmission and further attention should be paid to these areas. Standardization of sampling methods will improve understanding of levels of environmental contamination. The pandemic has demonstrated a need to review and act upon the challenges of older hospital buildings meeting current ventilation guidance.
Assuntos
COVID-19 , SARS-CoV-2 , Humanos , RNA Viral , Tratamento Farmacológico da COVID-19 , HospitaisRESUMO
BACKGROUND: Healthcare-acquired COVID-19 has been an additional burden on hospitals managing increasing numbers of patients with SARS-CoV-2. One acute hospital (W) among three in a Scottish healthboard experienced an unexpected surge of COVID-19 clusters. AIM: To investigate possible causes of COVID-19 clusters at Hospital W. METHODS: Daily surveillance provided total numbers of patients and staff involved in clusters in three acute hospitals (H, M and W) and care homes across the healthboard. All clusters were investigated and documented, along with patient boarding, community infection rates and outdoor temperatures from October 2020 to March 2021. Selected SARS-CoV-2 strains were genotyped. FINDINGS: There were 19 COVID-19 clusters on 14 wards at Hospital W during the six-month study period, lasting from two to 42 days (average, five days; median, 14 days) and involving an average of nine patients (range 1-24) and seven staff (range 0-17). COVID-19 clusters in Hospitals H and M reflected community infection rates. An outbreak management team implemented a control package including daily surveillance; ward closures; universal masking; screening; restricting staff and patient movement; enhanced cleaning; and improved ventilation. Forty clusters occurred across all three hospitals before a January window-opening policy, after which there were three during the remainder of the study. CONCLUSION: The winter surge of COVID-19 clusters was multi-factorial, but clearly exacerbated by moving trauma patients around the hospital. An extended infection prevention and control package including enhanced natural ventilation helped reduce COVID-19 clusters in acute hospitals.
Assuntos
COVID-19 , Atenção à Saúde , Hospitais , Humanos , SARS-CoV-2 , Escócia/epidemiologiaRESUMO
More evidence is emerging on the importance of the clinical environment in encouraging hospital infection. This review considers the role of cleaning as an effective means to control infection. It describes the location of pathogen reservoirs and methods for evaluating hospitals' cleanliness. Novel biocides, antimicrobial coatings and equipment are available, many of which have not been assessed against patient outcome. Cleaning practices should be tailored to clinical risk, given the wide-ranging surfaces, equipment and building design. There is confusion between nursing and domestic personnel over the allocation of cleaning responsibilities and neither may receive sufficient training and/or time to complete their duties. Since less labourious practices for dirt removal are always attractive, there is a danger that traditional cleaning methods are forgotten or ignored. Few studies have examined detergent-based regimens or modelled these against infection risk for different patient categories. Fear of infection encourages the use of powerful disinfectants for the elimination of real or imagined pathogens in hospitals. Not only do these agents offer false assurance against contamination, their disinfection potential cannot be achieved without the prior removal of organic soil. Detergent-based cleaning is cheaper than using disinfectants and much less toxic. Hospital cleaning in the 21st century deserves further investigation for routine and outbreak practices.
Assuntos
Infecção Hospitalar/prevenção & controle , Descontaminação/métodos , Desinfecção/métodos , Zeladoria Hospitalar/métodos , Controle de Infecções/métodos , Hospitais , HumanosRESUMO
A previous local study revealed high levels of fusidic acid (FA) resistance within dermatology. It was therefore decided to limit use of topical FA within dermatology and then assess the effect on resistance rates. The local microbiology department produced FA resistance data within dermatology over a five-year period. This was then compared with data provided for four other control specialties. Since withdrawal of FA in dermatology, between 2002 and 2006, there was a statistically significant fall in FA resistance rates, while the other four control specialty areas showed increases in resistance rates. In conclusion, it would appear that, in dermatology, withdrawal of topical FA could have a beneficial effect on overall resistance rates for this antibiotic. Given these findings, we made recommendations that other local dermatology units consider their policy on the routine use of topical fusidic preparations.
Assuntos
Antibacterianos/farmacologia , Ácido Fusídico/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Anti-Infecciosos Locais/farmacologia , Dermatologia , Farmacorresistência Bacteriana , Humanos , Staphylococcus aureus/isolamento & purificaçãoRESUMO
INTRODUCTION: Healthcare environmental surfaces may be contaminated with micro-organisms that cause healthcare-associated infections (HCAIs). Special attention is paid to near-patient surfaces but sites outside the patient zone receive less attention. This paper presents data on keyboard contamination and the risk of pathogen transmission from keyboards. METHODS: Keyboards from nursing stations in three hospitals and a dental practice were analysed for bacterial contamination. Surfaces were pre-treated to remove planktonic bacteria so that any remaining bacteria were presumed to be associated with biofilm. Bacterial transfer from keyboard keys was studied following wiping with sterile water or sodium hypochlorite. The presence of multi-drug-resistant organisms (MDROs) was sought using selective culture. RESULTS: Moist swabbing did not detect bacteria from any keyboard samples. Use of enrichment broth, however, demonstrated MDROs from most samples. Gram-negative bacteria were recovered from almost half (45%) of the samples, with meticillin-resistant Staphylococcus aureus, vancomycin-resistant enterococcus and MDR Acinetobacter spp. recovered from 72%, 31% and 17% of samples, respectively. Isolates were transferred from 69% of samples after wiping with sterile water, and from 54% of samples after wiping with 1000 ppm sodium hypochlorite. DISCUSSION: While moist swabbing failed to detect bacteria from keyboards, pathogens were recovered using enrichment culture. Use of water- or NaOCl-soaked wipes transferred bacteria from most samples tested. This study implies that hospital keyboards situated outside the patient zone commonly harbour dry surface biofilms (DSBs) that offer a potential reservoir for transferable pathogens. While the role of keyboards in transmission is uncertain, there is a need to pursue effective solutions for eliminating DSBs from keyboards.
Assuntos
Infecção Hospitalar , Staphylococcus aureus Resistente à Meticilina , Computadores , Infecção Hospitalar/prevenção & controle , Atenção à Saúde , Enterococcus , HumanosRESUMO
BACKGROUND: Increased length of stay (LOS) for patients is an important measure of the burden of healthcare-associated infection (HAI). AIM: To estimate the excess LOS attributable to HAI. METHODS: This was a one-year prospective incidence study of HAI observed in one teaching hospital and one general hospital in NHS Scotland as part of the Evaluation of Cost of Nosocomial Infection (ECONI) study. All adult inpatients with an overnight stay were included. HAI was diagnosed using European Centres for Disease Prevention and Control definitions. A multi-state model was used to account for the time-varying nature of HAI and the competing risks of death and discharge. FINDINGS: The excess LOS attributable to HAI was 7.8 days (95% confidence interval (CI): 5.7-9.9). Median LOS for HAI patients was 30 days and for non-HAI patients was 3 days. Using a simple comparison of duration of hospital stay for HAI cases and non-cases would overestimate the excess LOS by 3.5 times (27 days compared with 7.8 days). The greatest impact on LOS was due to pneumonia (16.3 days; 95% CI: 7.5-25.2), bloodstream infections (11.4 days; 5.8-17.0) and surgical site infection (SSI) (9.8 days; 4.5-15.0). It is estimated that 58,000 bed-days are occupied due to HAI annually. CONCLUSION: A reduction of 10% in HAI incidence could make 5800 bed-days available. These could be used to treat 1706 elective patients in Scotland annually and help reduce the number of patients awaiting planned treatment. This study has important implications for investment decisions in infection prevention and control interventions locally, nationally, and internationally.
Assuntos
Infecção Hospitalar , Adulto , Estudos de Coortes , Infecção Hospitalar/epidemiologia , Atenção à Saúde , Humanos , Tempo de Internação , Estudos ProspectivosRESUMO
BACKGROUND: Healthcare-associated infection (HAI) is associated with increased morbidity and mortality resulting in excess costs. AIM: To investigate the impact of all types of HAI on the inpatient cost of HAI using different approaches. METHODS: The incidence, types of HAI, and excess length of stay were estimated using data collected as part of the Evaluation of Cost of Nosocomial Infection (ECONI) study. Scottish NHS reference costs were used to estimate unit costs for bed-days. Variable (cash) costs associated with infection prevention and control (IPC) measures and treatment were calculated for each HAI type and overall. The inpatient cost of HAI is presented in terms of bed-days lost, bed-day costs, and cash costs. FINDINGS: In Scotland 58,010 (95% confidence interval: 41,730-74,840) bed-days were estimated to be lost to HAI during 2018/19, costing £46.4 million (19m-129m). The total annual cost in the UK is estimated to be £774 million (328m-2,192m). Bloodstream infection and pneumonia were the most costly HAI types per case. Cash costs are a small proportion of the total cost of HAI, contributing 2.4% of total costs. CONCLUSION: Reliable estimates of the cost burden of HAI management are important for assessing the cost-effectiveness of IPC programmes. This unique study presents robust economic data, demonstrating that HAI remains a burden to the UK NHS and bed-days capture the majority of inpatient costs. These findings can be used to inform the economic evaluation and decision analytic modelling of competing IPC programmes at local and national level.
Assuntos
Infecção Hospitalar , Pacientes Internados , Infecção Hospitalar/epidemiologia , Atenção à Saúde , Humanos , Tempo de Internação , Reino Unido/epidemiologiaRESUMO
BACKGROUND: Whereas the cost burden of healthcare-associated infection (HAI) extends beyond the inpatient stay into the post-discharge period, few studies have focused on post-discharge costs. AIM: To investigate the impact of all types of HAI on the magnitude and distribution of post-discharge costs observed in acute and community services for patients who developed HAI during their inpatient stay. METHODS: Using data from the Evaluation of Cost of Nosocomial Infection (ECONI) study and regression methods, this study identifies the marginal effect of HAI on the 90-daypost-discharge resource use and costs. To calculate monetary values, unit costs were applied to estimates of excess resource use per case of HAI. FINDINGS: Post-discharge costs increase inpatient HAI costs by 36%, with an annual national cost of £10,832,437. The total extra cost per patient with HAI was £1,457 (95% confidence interval: 1,004-4,244) in the 90 days post discharge. Patients with HAI had longer LOS if they were readmitted and were prescribed more antibiotics in the community. The results suggest that HAI did not have an impact on the number of readmissions or repeat surgeries within 90 days of discharge. The majority (95%) of the excess costs was on acute care services after readmission. Bloodstream infection, gastrointestinal infection, and pneumonia had the biggest impact on post-discharge cost. CONCLUSION: HAI increases costs and antibiotic consumption in the post-discharge period. Economic evaluations of IPC studies should incorporate post-discharge costs. These findings can be used nationally and internationally to support decision-making on the impact of IPC interventions.
Assuntos
Assistência ao Convalescente , Infecção Hospitalar , Infecção Hospitalar/epidemiologia , Atenção à Saúde , Humanos , Tempo de Internação , Alta do Paciente , Medicina EstatalRESUMO
BACKGROUND: Healthcare worker (HCW) behaviours, such as the sequence of their contacts with surfaces and hand hygiene moments, are important for understanding disease transmission. AIM: To propose a method for recording sequences of HCW behaviours during mock vs actual procedures, and to evaluate differences for use in infection risk modelling and staff training. METHODS: Procedures for three types of care were observed under mock and actual settings: intravenous (IV) drip care, observational care and doctors' rounds on a respiratory ward in a university teaching hospital. Contacts and hand hygiene behaviours were recorded in real-time using either a handheld tablet or video cameras. FINDINGS: Actual patient care demonstrated 70% more surface contacts than mock care. It was also 2.4 min longer than mock care, but equal in terms of patient contacts. On average, doctors' rounds took 7.5 min (2.5 min for mock care), whilst auxiliary nurses took 4.9 min for observational care (2.4 min for mock care). Registered nurses took 3.2 min for mock IV care and 3.8 min for actual IV care; this translated into a 44% increase in contacts. In 51% of actual care episodes and 37% of mock care episodes, hand hygiene was performed before patient contact; in comparison, 15% of staff delivering actual care performed hand hygiene after patient contact on leaving the room vs 22% for mock care. The number of overall touches in the patient room was a modest predictor of hand hygiene. Using a model to predict hand contamination from surface contacts for Staphylococcus aureus, Escherichia coli and norovirus, mock care underestimated micro-organisms on hands by approximately 30%.
Assuntos
Infecção Hospitalar , Higiene das Mãos , Controle de Infecções , Fidelidade a Diretrizes , Mãos , Desinfecção das Mãos , Pessoal de Saúde , Humanos , Assistência ao Paciente , Simulação de Paciente , Quartos de PacientesRESUMO
The coronavirus disease 2019 (COVID-19) pandemic has caused untold disruption throughout the world. Understanding the mechanisms for transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is key to preventing further spread, but there is confusion over the meaning of 'airborne' whenever transmission is discussed. Scientific ambivalence originates from evidence published many years ago which has generated mythological beliefs that obscure current thinking. This article collates and explores some of the most commonly held dogmas on airborne transmission in order to stimulate revision of the science in the light of current evidence. Six 'myths' are presented, explained and ultimately refuted on the basis of recently published papers and expert opinion from previous work related to similar viruses. There is little doubt that SARS-CoV-2 is transmitted via a range of airborne particle sizes subject to all the usual ventilation parameters and human behaviour. Experts from specialties encompassing aerosol studies, ventilation, engineering, physics, virology and clinical medicine have joined together to produce this review to consolidate the evidence for airborne transmission mechanisms, and offer justification for modern strategies for prevention and control of COVID-19 in health care and the community.
Assuntos
Aerossóis , Microbiologia do Ar , COVID-19/prevenção & controle , COVID-19/transmissão , Controle de Infecções/métodos , Pandemias/prevenção & controle , Ventilação/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , COVID-19/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , SARS-CoV-2Assuntos
Infecção Hospitalar/prevenção & controle , Parto Obstétrico/normas , Infecção Puerperal/prevenção & controle , Infecção Hospitalar/epidemiologia , Infecção Hospitalar/transmissão , Parto Obstétrico/efeitos adversos , Feminino , Humanos , Recém-Nascido , Transmissão de Doença Infecciosa do Profissional para o Paciente , Gravidez , Infecção Puerperal/epidemiologiaRESUMO
BACKGROUND: The environment has an important role in the transmission of healthcare associated infections. This has encouraged interest in novel methods to improve hygiene in hospitals. One such technology is the use of hydrogen peroxide to decontaminate rooms and equipment; there are, however, few studies that have investigated the effect of continuous dilute hydrogen peroxide (DHP) in the clinical environment. The aim of this study was to examine the use of dilute hydrogen peroxide (DHP) in a critical care unit and measure the microbiological impact on surface contamination. METHODS: We conducted a prospective observational cross-over study in a ten-bed critical care unit in one rural Australian hospital. Selected high-touch sites were screened using dipslides across three study phases: baseline; continuous DHP; and no DHP (control). Quantitative aerobic colony counts (ACC) were assessed against a benchmark standard of ACC >2.5 cfu/cm2 to indicate hygiene failure. RESULTS: There were low levels of microbial contamination in the unit for baseline; DHP; and no DHP phases: 2.2% (95% CI 0.7-5.4%) vs 7.7% (95% CI 4.3-13.0%) vs 6% (95% CI 3.2-10.4%) hygiene failures, respectively. Significant reduction in ACCs did not occur when the DHP was operating compared with baseline and control phases. CONCLUSION: Further work is needed to determine whether continuous DHP technology has a role in decontamination for healthcare settings.
Assuntos
Desinfecção , Peróxido de Hidrogênio , Controle de Infecções , Estudos Cross-Over , Humanos , Unidades de Terapia Intensiva , New South Wales , Estudos ProspectivosRESUMO
In the context of increasingly airtight homes, there is currently little known about the type and diversity of microorganisms in the home, or factors that could affect their abundance, diversity and nature. In this study, we examined the type and prevalence of cultivable microorganisms at eight different sites in 100 homes of older adults located in Glasgow, Scotland. The microbiological sampling was undertaken alongside a household survey that collated information on household demographics, occupant behaviour, building characteristics, antibiotic use and general health information. Each of the sampled sites revealed its own distinct microbiological character, in both species and number of cultivable microbes. While some potential human pathogens were identified, none were found to be multidrug resistant. We examined whether the variability in bacterial communities could be attributed to differences in building characteristics, occupant behaviour or household factors. Sampled sites furnished specific microbiological characteristics which reflected room function and touch frequency. We found that homes that reported opening windows more often were strongly associated with lower numbers of Gram-negative organisms at indoor sites (p < 0.0001). This work offers one of the first detailed analysis of cultivable microbes in homes of older adults and their relationship with building and occupancy related factors, in a UK context.
Assuntos
Poluição do Ar em Ambientes Fechados/análise , Bacillaceae/isolamento & purificação , Bactérias/crescimento & desenvolvimento , Habitação , Micrococcaceae/isolamento & purificação , Staphylococcaceae/isolamento & purificação , Atividades Cotidianas , Idoso , Bacillaceae/classificação , Características da Família , Fômites/microbiologia , Humanos , Micrococcaceae/classificação , Escócia , Staphylococcaceae/classificação , Tato/fisiologia , VentilaçãoRESUMO
BACKGROUND: Prompted by an outbreak of vancomycin-resistant enterococci (VRE) in a medical facility, this study examined a pneumatic tube transport system (PTS) as a potential transmission channel. METHOD: Samples from the receiving station and entry racks were gathered via smear technique. Sponges used for PTS decontamination were soaked with 0.89% NaCl and transported through the channel. Micro-organisms were recovered from the tubes and cleaning sponges using a wash-away technique. Air sampling was performed at the receiving station in order to detect any airborne contamination. Tubes were artificially inoculated with Escherichia coli K12 NCTC 10538 and Staphylococcus epidermidis DSM 20044 and sent through the PTS to investigate channel contamination. RESULTS: No pathogens were detected in effluent air from the PTS or in tubes during routine operation. Entry racks for the test tubes were contaminated with coagulase-negative staphylococci (CNS), aerobic bacilli, moulds and vancomycin-susceptible Enterococcus faecium. E. coli proved to be unsuitable for detecting bacterial transmission by the PTS due to low persistence, but S. epidermidis was more resilient. After sending contaminated test tubes through the PTS, levels of S. epidermidis only decreased marginally. Subsequently, sponges soaked with disinfectant solution were put through the system and these eliminated S. epidermidis completely from the first attempt. DISCUSSION: Routine hygienic maintenance of the PTS makes pathogen transmission highly unlikely, although entry racks should be disinfected regularly. Any involvement of the PTS in the VRE outbreak at the study institution was unlikely.
Assuntos
Infecção Hospitalar/prevenção & controle , Surtos de Doenças/prevenção & controle , Contaminação de Equipamentos , Higiene , Hospitais Universitários , Humanos , Medição de RiscoRESUMO
BACKGROUND: A previous study among neonatal intensive care unit (NICU) nurses showed that the antibacterial efficacy of alcohol-based handrubs (ABHR) can be achieved in 15 s instead of 30 s with a significant increase in the frequency of hand antisepsis. This study aimed to examine 15-s vs 30-s antisepsis performance by measuring microbial load on fingertips and compliance among nurses in a low-risk gynaecological ward. METHODS: An independent trained observer monitored the frequency and compliance with hand antisepsis during shifts in a crossover design. Fingertips including thumbs were rinsed in soy broth before hand rubbing at the beginning of a shift and then hourly to determine the bacterial load. Performance activity was assigned to the contamination class of the Fulkerson scale. Immediately before the lunch break, volunteers cleaned their hands for a randomly determined application time of 15 or 30 s. RESULTS: Examination of bacterial load on fingertips revealed no difference between 15 vs 30 s application time. Controlled hand antisepsis before the lunch break also showed no difference in efficacy for either test series. Participants rubbing for 15 s were more likely to perform hand antisepsis compared with those rubbing for 30 s (P=0.2). The compliance increased from 54.7% to 69.5% in the 15-s trial. DISCUSSION: Shortening the duration for hand antisepsis did not decrease efficacy. Shortening the application time to 15 s should be considered within the critical components of a successful multimodal intervention strategy to improve hand-hygiene compliance in clinical practice.
Assuntos
Anti-Infecciosos Locais/administração & dosagem , Antissepsia/métodos , Etanol/administração & dosagem , Desinfecção das Mãos/métodos , Mãos/microbiologia , Carga Bacteriana , Estudos Cross-Over , Alemanha , Humanos , Enfermeiras e EnfermeirosRESUMO
BACKGROUND: Now that cleaning and decontamination are recognized as integral to infection control, it is timely to examine the process in more detail. This is because cleaning practices vary widely within healthcare districts, and it is likely that both time and energy are needlessly wasted with ill-defined duties. Furthermore, inadequate cleaning will not reduce the risk of infection but may even enhance it. The process would benefit from a systematic appraisal, with each component placed within an evidence-based and ordered protocol. METHODS: A literary search was performed on 'hospital cleaning', focusing on manual aspects of cleaning, pathogen reservoirs and transmission, hand hygiene, staff responsibilities and patient comfort. RESULTS: No articles providing an evidence-based practical approach to systematic cleaning in hospitals were identified. This review therefore proposes a simple four-step guide for daily cleaning of the occupied bed space. Step 1 (LOOK) describes a visual assessment of the area to be cleaned; Step 2 (PLAN) argues why the bed space needs preparation before cleaning; Step 3 (CLEAN) covers surface cleaning/decontamination; and Step 4 (DRY) is the final stage whereby surfaces are allowed to dry. CONCLUSION: Given the lack of articles providing practical cleaning guidance, this review proposes a four-step protocol based on evidence if available, or justified where not. Each step is presented, discussed and risk-assessed. It is likely that a systematic cleaning process would reduce the risk of healthcare-associated infection for everyone, including outbreaks, in addition to heightened confidence in overall quality of care.
Assuntos
Infecção Hospitalar/prevenção & controle , Descontaminação/métodos , Transmissão de Doença Infecciosa/prevenção & controle , Desinfecção/métodos , Hospitais , Infecção Hospitalar/transmissão , Guias como Assunto , HumanosRESUMO
BACKGROUND: Staphylococcus aureus remains an important bacterial pathogen worldwide. This study utilized known staphylococcal epidemiology to track S. aureus between different ecological reservoirs in one 10-bed intensive care unit (ICU). METHODS: Selected hand-touch surfaces, staff hands and air were screened systematically 10 times during 10 months, with patients screened throughout the study. S. aureus isolates were subjected to spa typing and epidemiological analyses, followed by whole-genome sequencing to provide single nucleotide polymorphism (SNP) data. RESULTS: Multiple transmission pathways between patients and reservoirs were investigated. There were 34 transmission events, of which 29 were highly related (<25 SNPs) and five were possibly related (<50 SNPs). Twenty (59%) transmission events occurred between colonized patients and their own body sites (i.e. autogenous spread); four (12%) were associated with cross-transmission between patients; four (12%) occurred between patients and hand-touch sites (bedrails and intravenous pump); four (12%) linked airborne S. aureus with staff hands and bedrail; and two (6%) linked bed tables, bedrail and cardiac monitor. CONCLUSION: Colonized patients are responsible for repeated introduction of new S. aureus into the ICU, whereupon a proportion spread to hand-touch sites in (or near) the patient zone. This short-term reservoir for S. aureus imposes a colonization/infection risk for subsequent patients. More than half of ICU-acquired S. aureus infection originated from the patients' own flora, while staff hands and air were rarely implicated in onward transmission. Control of staphylococcal infection in the ICU is best served by patient screening, systematic cleaning of hand-touch surfaces and continued emphasis on hand hygiene.
Assuntos
Infecção Hospitalar/epidemiologia , Infecção Hospitalar/microbiologia , Unidades de Terapia Intensiva , Infecções Estafilocócicas/epidemiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/classificação , Sequenciamento Completo do Genoma , Infecção Hospitalar/transmissão , Transmissão de Doença Infecciosa , Microbiologia Ambiental , Mãos/microbiologia , Humanos , Epidemiologia Molecular , Tipagem Molecular , Polimorfismo de Nucleotídeo Único , Infecções Estafilocócicas/transmissão , Staphylococcus aureus/genética , Staphylococcus aureus/isolamento & purificaçãoRESUMO
Antimicrobial drugs encourage the overgrowth of organisms resistant to the agents used. Acquisition and subsequent overgrowth of methicillin-resistant Staphylococcus aureus (MRSA) are particularly associated with beta-lactam antibiotics and quinolones. These drugs allow rapid proliferation of an organism that might have been merely colonizing the skin, leading to clinical infection, treatment difficulties and potential transmission to others. In addition, there is increasing evidence that inappropriate antibiotics not only encourage overgrowth with MRSA but may also enhance pathogenicity. Such virulence is not necessarily due to simple expansion of MRSA across skin and mucosal surfaces; there appear to be molecular changes that facilitate mechanisms such as quorum sensing, adhesion, phage mobilization, exotoxin production, intracellular persistence and biofilm formation, all of which contribute towards more severe infection. This review examines the association between MRSA and certain classes of antibiotics and explores the molecular mechanisms underlying a perceived increase in virulence following inappropriate therapy. It is possible that empirical prescribing has a significant impact on the management of MRSA infections and ultimately patient outcome. It is time to challenge the prescribers' right to prescribe what they like, when they like, for patients at risk of MRSA.
Assuntos
Antibacterianos/farmacologia , Resistência a Meticilina/efeitos dos fármacos , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Animais , Antibacterianos/uso terapêutico , Humanos , Resistência a Meticilina/fisiologia , Infecções Estafilocócicas/microbiologia , Infecções Estafilocócicas/mortalidadeRESUMO
More and more hospitals are introducing universal screening for meticillin-resistant Staphylococcus aureus (MRSA). As with many other interventions imposed in the name of infection control, the evidence for benefit remains controversial. Despite this, screening has aroused political interest and has now become mandatory in some countries. This Leader examines the implications of introducing universal screening for MRSA. In addition to resource requirements, there are practical difficulties and consequences that may not have been fully considered. These include: staff recruitment and working time arrangements in the laboratory; specificity and sensitivity of selected screening sites and laboratory methods; lack of isolation facilities on the wards; timely and continuing management of MRSA-infected and/or -colonised patients; and ethical issues raised by screening patients without considering the role of colonised staff. Furthermore, the focus on MRSA promotes undue emphasis of its importance, which could facilitate legal interest. We should remember that it is the precipitant actions from finding a new MRSA patient that aids control, not the simple act of screening by itself. There is no doubt that universal screening should be explored as a mechanism for controlling MRSA, but more evidence is required before it becomes routine.