Methicillin-resistant Staphylococcus Aureus Bloodstream Infections Research Articles

Methicillin-resistant Staphylococcus aureus bloodstream infections in a Japanese University Hospital between 1987 and 2004

Methicillin-resistant Staphylococcus aureus (MRSA) infections have been the most common cause of nosocomial infections in Japan, but their genetic characteristics related to bloodstream infections have not been well studied. The aim of this study was to investigate a comprehensive molecular characterization of MRSA blood isolates during the historical 18-year study period between 1987 and 2004 in a tertiary care university hospital. A total of 137 MRSA isolates recovered from the blood of inpatients at Fukuoka University Hospital were analyzed. Clinical information and antimicrobial susceptibility profiles were reviewed, and staphylococcal chromosomal cassette mec (SCCmec), accessory gene regulator (agr), and a battery of bacterial genes were tested by PCR-based assays. The relatedness of these isolates was determined by the repetitive sequence-based PCR (rep-PCR) and pulsed-field gel electrophoresis (PFGE). Although low numbers of agr type III/SCCmec type IV isolates circulated between 1987 and 1992, agr type II/SCCmec type II isolates started circulating in 1993 and were responsible for the increased MRSA isolates until 2004. The rep-PCR and PFGE identified 104 epidemic and 33 sporadic isolates. Among the 104 epidemic isolates, six major rep-PCR/PFGE types were identified, which occupied 67.3% of epidemic isolates. The SCCmec type II and agr type II isolates were observed in significantly higher proportion in epidemic isolates than in sporadic isolates (P = 0.0318, P = 0.0123, respectively). In contrast, SCCmec type IV strains were observed in significantly higher proportion in sporadic isolates than in epidemic isolates (P = 0.0494). Although isolates with sec were detected in higher rates in epidemic isolates (P = 0.0397), seh was detected in higher rates in sporadic isolates (P = 0.0350). Multivariate logistic regression analysis with forward stepping revealed that SCCmec type II was independently associated with epidemic isolates (P = 0.0067; odds ratio, 1.75; 95% confidence interval, 1.17-2.64). These data indicated that SCCmec type II MRSA isolates were responsible for the increased MRSA bloodstream infections for inpatients during the 18-year study period in the hospital.

Mortality and Hospital Stay Associated with Resistant Staphylococcus aureus and Escherichia coli Bacteremia: Estimating the Burden of Antibiotic Resistance in Europe

The relative importance of human diseases is conventionally assessed by cause-specific mortality, morbidity, and economic impact. Current estimates for infections caused by antibiotic-resistant bacteria are not sufficiently supported by quantitative empirical data. This study determined the excess number of deaths, bed-days, and hospital costs associated with blood stream infections (BSIs) caused by methicillin-resistant Staphylococcus aureus (MRSA) and third-generation cephalosporin-resistant Escherichia coli (G3CREC) in 31 countries that participated in the European Antimicrobial Resistance Surveillance System (EARSS). The number of BSIs caused by MRSA and G3CREC was extrapolated from EARSS prevalence data and national health care statistics. Prospective cohort studies, carried out in hospitals participating in EARSS in 2007, provided the parameters for estimating the excess 30-d mortality and hospital stay associated with BSIs caused by either MRSA or G3CREC. Hospital expenditure was derived from a publicly available cost model. Trends established by EARSS were used to determine the trajectories for MRSA and G3CREC prevalence until 2015. In 2007, 27,711 episodes of MRSA BSIs were associated with 5,503 excess deaths and 255,683 excess hospital days in the participating countries, whereas 15,183 episodes of G3CREC BSIs were associated with 2,712 excess deaths and 120,065 extra hospital days. The total costs attributable to excess hospital stays for MRSA and G3CREC BSIs were 44.0 and 18.1 million Euros (63.1 and 29.7 million international dollars), respectively. Based on prevailing trends, the number of BSIs caused by G3CREC is likely to rapidly increase, outnumbering the number of MRSA BSIs in the near future. Excess mortality associated with BSIs caused by MRSA and G3CREC is significant, and the prolongation of hospital stay imposes a considerable burden on health care systems. A foreseeable shift in the burden of antibiotic resistance from Gram-positive to Gram-negative infections will exacerbate this situation and is reason for concern.

Trends in antimicrobial resistance in intensive care units in the United States

Antimicrobial resistance and a paucity of new antimicrobial agents are ongoing challenges. This review focuses on the major epidemiologic trends and novel treatments, when available, for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococcus, Clostridium difficile, and multidrug-resistant Gram-negative bacilli in the United States during 2010-2011. MRSA bloodstream infection rates have declined, primarily due to interventions aimed at decreasing vascular catheter infections. The proportion of MRSA due to the community-associated strain USA300 continues to increase. Recent studies of active surveillance and contact isolation for MRSA prevention provide conflicting views of efficacy. Two novel treatments for recurrent C. difficile infection, monoclonal antibodies and fidaxomicin, show promising results. Antimicrobial resistance among Gram-negative bacilli has become widespread; extended-spectrum beta-lactamases are now commonly found among Escherichia coli causing community-acquired infections in the United States. Klebsiella pneumoniae carbapenemases have spread beyond the northeast, and the New Delhi metallo-beta-lactamase has been reported in multiple countries within a few years of its discovery. Antimicrobial resistance, particularly among Gram-negative bacilli, continues to increase at a rapid rate. Given the frequent transfer of patients between outpatient and acute care settings, as well as between different geographic regions, coordinated infection control interventions are warranted.

Predictors of agr Dysfunction in Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates among Patients with MRSA Bloodstream Infections

Despite emerging evidence that dysfunction in the accessory gene regulator (agr) locus is associated with deleterious outcomes among patients treated with vancomycin for methicillin-resistant Staphylococcus aureus (MRSA) infections, factors predictive of agr dysfunction have not been evaluated. This study describes the epidemiology of agr dysfunction, identifies predictors of agr dysfunction in MRSA isolates among those with MRSA bloodstream infections, and describes the relationship between agr dysfunction and other microbiologic phenotypes. A cross-sectional study of patients with MRSA bloodstream infections at two institutions in upstate New York was performed. Clinical data on demographics, comorbidities, disease severity, hospitalization history, and antibiotic history were collected. Microbiologic phenotypes, including agr dysfunction, MIC values by broth microdilution (BMD) and Etest, and vancomycin heteroresistance (hVISA) were tested. Multivariable analyses were performed to identify factors predictive of agr dysfunction. Among 200 patients with an MRSA bloodstream infection, the proportion of strains with agr dysfunction was 31.5%. The distribution of MICs determined by both BMD and Etest were equivalent across agr groups, and there was no association between agr dysfunction and the presence of hVISA. Severity of illness, comorbidities, and hospitalization history were comparable between agr groups. In the multivariate analysis, prior antibiotic exposure was the only factor of variables studied found to be predictive of agr dysfunction. This relationship was predominantly driven by prior beta-lactam and fluoroquinolone administration in the bivariate analysis. Identifying these institution-specific risk factors can be used to develop a process to assess the risk of agr dysfunction and guide empirical antibiotic therapy decisions.

Successful Control of Methicillin-Resistant Staphylococcus aureus in Endemic Neonatal Intensive Care Units—A 7-Year Campaign

BackgroundMethicillin-resistant Staphylococcus aureus (MRSA) is among the most important nosocomial pathogens in the intensive care unit (ICU) worldwide, including Taiwan. Since 1997, our neonatal ICUs (NICUs) had become endemic for MRSA.Methodology/Principal FindingsTo control MRSA spread in our NICUs, we implemented a series of infection control measures stepwise, including reinforcement of hand hygiene since January 2000, augmentation of aseptic care over the insertion site of central venous catheter since July 2001, introduction of alcohol-based handrubs since April 2003, surveillance culture for MRSA and cohort care for the colonized patients between March 2003 and February 2004, and surveillance culture with subsequent decolonization of MRSA between August 2005 and July 2006. After implementation of these measures, MRSA healthcare-associated infection (HAI) density reduced by 92%, from 5.47 episodes per 1000 patient-days in 1999 to 0.45 episodes per 1000 patient-days in 2006; MRSA bloodstream infection reduced from 40 cases in 1999 to only one case in 2006. Compared to those obtained during the period of surveillance culture without decolonization, both rates of MRSA colonization (8.6% vs. 41%, p<0.001) and infection (1.1% vs. 12%, p<0.001) decreased significantly during the period of surveillance and decolonization. Molecular analysis of the clinical isolates during the study period showed that the endemic clone, which dominated between 1998 and 2005, almost disappeared in 2006, while the community clones increased significantly in 2006–2007.Conclusion/SignificanceThrough infection control measures, MRSA HAIs can be successfully controlled, even in areas with high levels of endemic MRSA infections such as our NICUs.

A targeted methicillin-resistant Staphylococcus aureus (MRSA) control program did not affect total nosocomial Staphylococcus aureus (SA) bloodstream infections (BSI) despite reducing MRSA BSI

Background: Intense efforts at reducing MRSA infections have been used in Singapore hospitals from 2007 with active surveillance, intense hand hygiene campaigns, public displays of surveillance results and audio and visual reminders. Aim: We evaluated the impact of this campaign on overall Staphylococcus aureus (SA) bloodstream infection rates.

Certification in Infection Control Matters: Impact of Infection Control Department Staffing Characteristics and Hospital Policies on Rates of MRSA Bloodstream Infections

Infections due to methicillin-resistant Staphylococcus aureus (MRSA) cause significant morbidity and mortality in the hospital setting. The purpose of this study was to assess the relationship between MRSA infection control (IC) policies, IC department staffing and rates of MRSA bloodstream infections (BSI).

Clinical Impact of Antimicrobial Resistance in European Hospitals: Excess Mortality and Length of Hospital Stay Related to Methicillin-Resistant Staphylococcus aureus Bloodstream Infections

Antimicrobial resistance is threatening the successful management of nosocomial infections worldwide. Despite the therapeutic limitations imposed by methicillin-resistant Staphylococcus aureus (MRSA), its clinical impact is still debated. The objective of this study was to estimate the excess mortality and length of hospital stay (LOS) associated with MRSA bloodstream infections (BSI) in European hospitals. Between July 2007 and June 2008, a multicenter, prospective, parallel matched-cohort study was carried out in 13 tertiary care hospitals in as many European countries. Cohort I consisted of patients with MRSA BSI and cohort II of patients with methicillin-susceptible S. aureus (MSSA) BSI. The patients in both cohorts were matched for LOS prior to the onset of BSI with patients free of the respective BSI. Cohort I consisted of 248 MRSA patients and 453 controls and cohort II of 618 MSSA patients and 1,170 controls. Compared to the controls, MRSA patients had higher 30-day mortality (adjusted odds ratio [aOR] = 4.4) and higher hospital mortality (adjusted hazard ratio [aHR] = 3.5). Their excess LOS was 9.2 days. MSSA patients also had higher 30-day (aOR = 2.4) and hospital (aHR = 3.1) mortality and an excess LOS of 8.6 days. When the outcomes from the two cohorts were compared, an effect attributable to methicillin resistance was found for 30-day mortality (OR = 1.8; P = 0.04), but not for hospital mortality (HR = 1.1; P = 0.63) or LOS (difference = 0.6 days; P = 0.96). Irrespective of methicillin susceptibility, S. aureus BSI has a significant impact on morbidity and mortality. In addition, MRSA BSI leads to a fatal outcome more frequently than MSSA BSI. Infection control efforts in hospitals should aim to contain infections caused by both resistant and susceptible S. aureus.

Sustained Reduction in the Clinical Incidence of Methicillin-Resistant Staphylococcus aureus Colonization or Infection Associated with a Multifaceted Infection Control Intervention

To assess the impact and sustainability of a multifaceted intervention to prevent methicillin-resistant Staphylococcus aureus (MRSA) transmission implemented in 3 chronologically overlapping phases at 1 hospital. Interrupted time-series analyses. A Veterans Affairs hospital in the northeastern United States. Individuals admitted to acute care units from October 1, 1999, through September 30, 2008. To calculate the monthly clinical incidence of MRSA colonization or infection, the number of MRSA-positive cultures obtained from a clinical site more than 48 hours after admission among patients with no MRSA-positive clinical cultures during the previous year was divided by patient-days at risk. Secondary outcomes included clinical incidence of methicillin-sensitive S. aureus colonization or infection and incidence of MRSA bloodstream infections. The intervention--implemented in a surgical ward beginning October 2001, in a surgical intensive care unit beginning October 2003, and in all acute care units beginning July 2005--included systems and behavior change strategies to increase adherence to infection control precautions (eg, hand hygiene and active surveillance culturing for MRSA). Hospital-wide, the clinical incidence of MRSA colonization or infection decreased after initiation of the intervention in 2001, compared with the period before intervention (P = .002), and decreased by 61% (P < .001) in the 7-year postintervention period. In the postintervention period, the hospital-wide incidence of MRSA bloodstream infection decreased by 50% (P = .02), and the proportion of S. aureus isolates that were methicillin resistant decreased by 30% (P < .001). Sustained decreases in hospital-wide clinical incidence of MRSA colonization or infection, incidence of MRSA bloodstream infection, and proportion of S. aureus isolates resistant to methicillin followed implementation of a multifaceted prevention program at one Veterans Affairs hospital. Findings suggest that interventions designed to prevent transmission can impact endemic antimicrobial resistance problems.

Comparison of Incidence of Bloodstream Infection with Methicillin‐ResistantStaphylococcusaureusbetween England and United States, 2006–2007

We compared incidence of methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) in the United States and England by using population-based surveillance. The incidence of community-onset MRSA BSI was 6.3-fold higher in the United States than in England, whereas the incidence of hospital-onset MRSA BSI was similar between the 2 countries.

Methicillin-resistant Staphylococcus aureus nasal colonization is a poor predictor of intensive care unit-acquired methicillin-resistant Staphylococcus aureus infections requiring antibiotic treatment

To test whether intensive care unit (ICU) nasal screening for methicillin-resistant Staphylococcus aureus (MRSA) predicts the presence or absence of MRSA infections requiring antimicrobial treatment. A prospective cohort study. Medical ICU at Barnes-Jewish Hospital, a 1252-bed urban teaching hospital. Seven hundred forty-nine consecutive patients admitted to the medical ICU over a 7-mo period (November 2007 through June 2008). Nasal swabs were obtained at ICU admission and weekly thereafter for MRSA detection by using polymerase chain reaction. All subjects were followed for the development of MRSA infection during their ICU stay. One hundred sixty-four (21.9%) patients had positive nasal colonization with MRSA at the time of ICU admission. The predictive accuracy of MRSA nasal colonization for ICU-acquired MRSA infections, either lower respiratory tract infection or bloodstream infection, was poor (lower respiratory tract infection: sensitivity, 24.2%; specificity, 78.5%; positive predictive value, 17.7%; and negative predictive value, 84.4%; and bloodstream infection: sensitivity, 23.1%; specificity, 78.2%; positive predictive value, 11.0%; and negative predictive value, 89.7%). Addition of nasal-colonization results obtained during the ICU stay did not appreciably change the predictive accuracy of this test for identification of subsequent lower respiratory tract infections and bloodstream infections attributed to MRSA requiring antimicrobial treatment. In this analysis, nasal colonization with MRSA was found to be a poor predictor for the subsequent occurrence of MRSA lower respiratory tract infections and MRSA bloodstream infections requiring antimicrobial treatment. Clinicians should be cautious in using the results of nasal-colonization testing to determine the need for MRSA treatment among patients with ICU-acquired infections.

Risk factors for mortality of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection: With investigation of the potential role of community-associated MRSA strains

The difference in the outcomes of nosocomial bloodstream infection (BSI) caused by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains and healthcare-associated MRSA (HA-MRSA) strains remains unclear. From January 1, 2006 to December 31, 2008, all adult patients hospitalized at National Taiwan University Hospital with nosocomial MRSA BSI were analyzed. Available MRSA isolates were submitted for subsequent microbiologic studies to determine whether they belonged to CA-MRSA strains. In total, 308 patients were enrolled and 253 MRSA isolates were available. Forty-seven isolates belonged to CA-MRSA strains. The all-cause mortality rates on Day 14 and Day 30 were 19.8% and 30.5%, respectively, and were not different between those caused by CA-MRSA and HA-MRSA strains. The independent risk factors for Day 14 mortality were septic shock, thrombocytopenia, and an inadequate serum trough level of vancomycin (p = <0.0001, 0.0003, and 0.0381, respectively). Those for Day 30 mortality were septic shock, anemia, thrombocytopenia, presence of underlying malignancies, and MRSA isolates with a vancomycin minimum inhibitory concentration of 2 mg/L (p = <0.0001, 0.0425, 0.0007, 0.0098, and 0.0012, respectively). The mortality rates of nosocomial MRSA BSI were not different between that caused by CA-MRSA and HA-MRSA strains.

Health Care–Associated Invasive MRSA Infections, 2005-2008

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen of public health importance; MRSA prevention programs that may affect MRSA transmission and infection are increasingly common in health care settings. Whether there have been changes in MRSA infection incidence as these programs become established is unknown; however, recent data have shown that rates of MRSA bloodstream infections (BSIs) in intensive care units are decreasing. To describe changes in rates of invasive health care-associated MRSA infections from 2005 through 2008 among residents of 9 US metropolitan areas. Active, population-based surveillance for invasive MRSA in 9 metropolitan areas covering a population of approximately 15 million persons. All reports of laboratory-identified episodes of invasive (from a normally sterile body site) MRSA infections from 2005 through 2008 were evaluated and classified based on the setting of the positive culture and the presence or absence of health care exposures. Health care-associated infections (ie, hospital-onset and health care-associated community-onset), which made up 82% of the total infections, were included in this analysis. Change in incidence of invasive health care-associated MRSA infections and health care-associated MRSA BSIs using population of the catchment area as the denominator. From 2005 through 2008, there were 21,503 episodes of invasive MRSA infection; 17,508 were health care associated. Of these, 15,458 were MRSA BSIs. The incidence rate of hospital-onset invasive MRSA infections was 1.02 per 10,000 population in 2005 and decreased 9.4% per year (95% confidence interval [CI], 14.7% to 3.8%; P = .005), and the incidence of health care-associated community-onset infections was 2.20 per 10,000 population in 2005 and decreased 5.7% per year (95% CI, 9.7% to 1.6%; P = .01). The decrease was most prominent for the subset of infections with BSIs (hospital-onset: -11.2%; 95% CI -15.9% to -6.3%; health care-associated community-onset: -6.6%; 95% CI -9.5% to -3.7%). Over the 4-year period from 2005 through 2008 in 9 diverse metropolitan areas, rates of invasive health care-associated MRSA infections decreased among patients with health care-associated infections that began in the community and also decreased among those with hospital-onset invasive disease.

USA600 (ST45) Methicillin-Resistant Staphylococcus aureus Bloodstream Infections in Urban Detroit

Methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a major source of invasive infections, implicated in 18,000 deaths annually ([9][1]). Mortality rates of 20 to 30% for patients with MRSA bloodstream infections (BSIs) have been reported, with a recent study, spanning 15 years,

Risk Factors for Acquiring Vancomycin-Resistant Enterococcus and Methicillin-Resistant Staphylococcus aureus on a Burn Surgery Step-Down Unit

The incidence of hospital-associated infections secondary to methicillin-resistant Staphylococcus aureus (MRSA) and those caused by vancomycin-resistant enterococci (VRE) continue to increase, despite the publication of evidence-based guidelines on infection control. We sought to determine modifiable risks factors for acquisition of MRSA or VRE or both on a burn trauma unit (BTU). We performed a retrospective single-center-matched control study. Our study group comprised 94 patients who acquired MRSA or VRE or both while on the BTU from January 1, 2001 to December 31, 2005. The case-patients were matched 1:1 to control-patients based on the time the cases were exposed to the BTU before they became colonized or infected. Logistic regression was used to analyze the relationship of demographic, procedure, and antimicrobial exposure variables to acquisition of MRSA or VRE. Acquisition of MRSA or VRE was related to patient factors, antimicrobial exposure, and device use. Younger age and prior vancomycin treatment while on the BTU were independently associated with MRSA acquisition. The presence of a Foley catheter was related to VRE acquisition. Sixteen study patients (17.0%) who became colonized on the BTU subsequently acquired 17 infections: six patients had MRSA bloodstream infections, nine had MRSA burn wound infections, and two had VRE urinary tract infections. Younger age, exposure to vancomycin, or Foley catheters were associated with increased risk of acquiring MRSA or VRE. Protocols or algorithms that help physicians remember to assess the necessity of antimicrobial agents and devices may help limit the duration of exposure to these risk factors, which may enhance infection prevention efforts. Future studies need to explore the effect of these variables on cross-transmission and their impact predominately in a burn unit.

Trend of vancomycin MIC values among MRSA clinical isolates and association with patient outcome

Background: Methicillin-resistant Staphylococcus aureus (MRSA) has become a common cause of nosocomial and community-acquired infection. Vancomycin has become the drug of choice given the emergence of MRSA; however, studies have reported an increase in the vancomycin minimum inhibitory concentration (MIC) and vancomycin treatment failure despite MICs within the susceptible range ()2 μg/mL). Limited studies have examined whether this increase in vancomycin MIC is associated with patient outcome. Methods: We reviewed the medical records of patients diagnosed with MRSA bloodstream or lower extremity wound infection from January 1, 1998 through December 31, 2008. Bivariate and multivariate analyses were conducted to examine the association between vancomycin MIC and other covariates. Results: 97 patients were diagnosed with a MRSA infection; 65% (63/97) of patients had a bloodstream infection and 35% (34/97) of patients had a wound infection. From 1998 to 2003, MRSA with a low vancomycin MIC (≤1 μg/mL) were in the majority; however, from 2004 to 2008, MRSA with a high MIC (=2 μgg/mL) were in the majority. Therefore, over time, there was a significant upward trend in vancomycin MIC values (p = 0.01). Logistic regression analysis revealed that a high vancomycin MIC was significantly associated with a past medical history of malignancy (p = 0.04) and death within 30 days of infection (p = 0.04) compared to a low vancomycin MIC. Conclusion: Our study has shown (1) vancomycin MIC values have displayed an upward ‘creep’ over time, and (2) high MIC values of vancomycin is significantly related to a past medical history of malignancy as well as higher mortality within 30 days of MRSA infection. Further prospective studies are needed to examine the clinical significance of an upward ‘creep’ in vancomycin MIC values. Abstracts for SupplementInternational Journal of Infectious DiseasesVol. 14Preview Full-Text PDF Open Archive

The management of methicillin-resistant Staphylococcus aureus infection in Europe

Methicillin-resistant Staphylococcus aureus (MRSA) has been a common nosocomial pathogen since the 1960s and has become a major problem in hospitals worldwide. In 2007, the European Antimicrobial Resistance Surveillance System, a free network that connects more than 600 laboratories in 31 European countries, reported an incidence of MRSA bloodstream infection (BSI) per 100 000 patient-days ranging from 0.2 in Sweden to 24.4 in Portugal [1]. A meta-analysis showed that BSIs due to MRSA are associated with almost two-fold higher mortality than those due to methicillin-susceptible S. aureus [2]. Costs were significantly higher for MRSA BSI than for methicillin-susceptible S. aureus BSI [3]. Therefore, patients and the public increasingly view rates of hospital-acquired MRSA as indicators of quality of patient care. Detection and eradication of MRSA are becoming public health priorities worldwide [4,5]. There has been much debate about the evidence and cost-effectiveness of various infection control policies in controlling MRSA. A multidisciplinary approach should be employed in all settings, including hand hygiene programmes, active surveillance cultures, training of and feedback to healthcare workers, bundles for ventilator-associated pneumonia and central venous catheter-related infections, and environmental programmes [6,7]. A second, even more essential, aspect of the management of MRSA is the treatment of serious infections, which must be prompt and efficacious in order to allow rapid microbiological clearance and successful management of the infection. It is also important to maintain appropriate and constant antibiotic serum concentrations [8–10]. Therapy for MRSA infections has to be decided individually, with consideration of the susceptibility patterns, source of the infection, presence of metastatic sites of infection, comorbidities, and history of patient allergies. A number of questions remain unsolved for the treatment of severe MRSA infections (BSI, endocarditis, osteomyelitis, and pneumonia). Although the glycopeptides still constitute the drugs of choice, there are several concerns about the treatment of MRSA infections: reports of clinical failure with vancomycin treatment regardless of in vitro susceptibility; increasing reports of strains with reduced vancomycin susceptibility; difficulty in therapeutic dosage monitoring; and lack of evidence on the efficacy of combination therapy. Moreover, in recent years, pharmaceutical companies have curtailed antibiotic production. Linezolid, daptomycin and tigecycline are the only three really innovative drugs for the treatment of MRSA infections produced in the last 20 years. At present, although the availability of linezolid, daptomycin and tigecycline has definitely improved options for the treatment of MRSA infections, the use of these antibacterials should be carefully monitored, to avoid the future spread of resistance. In addition, the therapeutic roles of the glycopeptides and the relevance of MICs need redefining. The selection of multidrug-resistant MRSA would have significant consequences at the individual level (i.e. increased risk of infection in a colonized patient) and at the institutional level (i.e. increased risk of cross-transmission among hospitalized patients, environmental contamination, and spread of resistance in the community). For the updating of existing guidelines, new trials are needed to compare these new drugs for the treatment of severe infections due to MRSA. Nevertheless, major efforts should be focused on improving specific guidelines for hospital antibiotic use and infection control measures to reduce the nosocomial spread of multidrugresistant MRSA strains. Interestingly, although specific guidelines for the management of MRSA infections have been published in many European countries, there is no common agreement, and treatment is still heterogeneous [11–13]. For certain clinical practices in the management of MRSA, e.g. the use of older drugs, combination therapy, intravenous–oral switch, and duration of treatment, clear evidence does not exist. Therefore, a large survey was proposed to canvass current opinions and practice in the management and treatment of MRSA infection among practitioners across Europe, concentrating on some of these controversial areas. An expert faculty developed a series of questions and gave their own

A survey of attitudes towards methicillin-resistant Staphylococcus aureus bacteraemias amongst United Kingdom microbiologists

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSIs) in the UK are common and associated with significant morbidity and mortality. Vancomycin is the usual first-line therapy. However, vancomycin treatment of BSIs due to MRSA strains with vancomycin MICs of 1-2 mg/L is successful in <10% of cases. No consensus exists on when to use newer agents, particularly when vancomycin MICs are >1 mg/L. We therefore surveyed UK practices of the management of MRSA BSIs due to isolates with increased vancomycin MICs. Five hundred and seventy-one UK consultant microbiologists were contacted via e-mail and asked to take part in an online survey, hosted at www.surveymonkey.com. Responses were collated by the website, downloaded and analysed in a Microsoft Excel (Microsoft Corporation) spreadsheet. One hundred and eight respondents participated in the survey. Only 32.7% routinely measure MICs, mostly by Etest. Forty-two percent use vancomycin alone for removable-focus infections, whilst for infections of cardiac or orthopaedic origin, 49% would add rifampicin. Few respondents use daptomycin, linezolid or tigecycline empirically. Sixty-nine percent would use linezolid as a second-line agent, with only 19% opting for daptomycin. For an isolate with a vancomycin MIC of 4 mg/L, respondents would use daptomycin (81%) or linezolid (91%) in patients with a poor clinical response. Vancomycin is the mainstay therapy for MRSA BSIs, even when MICs are not measured or raised, despite evidence of high failure rates. The use of newer agents frequently does not follow European or US licensed indications, may be inappropriate and may result in avoidable deaths.

Empirical Antimicrobial Therapy for Bloodstream Infection Due to Methicillin-Resistant Staphylococcus aureus: No Better than a Coin Toss

Despite the high prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection in the hospital, the proportion of patients with MRSA bacteremia who receive appropriate empirical therapy remains suboptimal. To investigate the proportion of patients with MRSA bloodstream infection (BSI) who received appropriate empirical antibiotic therapy and to identify risk factors associated with receipt of appropriate empirical therapy. We studied a cohort of patients from 10 hospitals. The primary outcome was the proportion of patients who received appropriate empirical antibiotic therapy for MRSA BSI. Appropriate therapy was defined as receipt of daptomycin, linezolid, quinupristin-dalfopristin, or vancomycin within 1 calendar day after the first blood culture result positive for S. aureus (ie, before antimicrobial susceptibilities were known). Multivariable logistic regression was used to determine variables associated with receipt of appropriate empirical therapy. The study included 562 patients with MRSA BSI. The mean (+/-standard deviation) age of the patients was 64 +/- 16 years, and 288 (51.2%) were male. Only 291 (51.8%) patients received appropriate empirical therapy. Patients were more likely to receive appropriate therapy if they required hemodialysis (odds ratio [OR], 1.36 [95% confidence interval {CI}, 1.00-1.85]), had undergone knee or hip arthroplasty (OR, 3.04 [95% CI, 1.21-7.6]), had a central venous catheter at admission (OR, 1.72 [95% CI, 1.01-2.93]), or had a McCabe score of 1 at admission (OR, 1.83 [95% CI, 1.16-2.83]). Bowel incontinence (OR, 0.41 [95% CI, 0.19-0.92]) and BSIs categorized as primary (OR, 0.41 [95% CI, 0.27-0.63]) were associated with a decreased likelihood of receiving appropriate empirical therapy. Only half of patients with MRSA BSI received appropriate empirical therapy. Factors associated with receiving appropriate empirical antibiotics included the presence of a central venous catheter at admission and a history of joint arthroplasty. Surprisingly, prior MRSA infection was not predictive of receipt of appropriate antimicrobial therapy.

The effect of daily bathing with chlorhexidine on the acquisition of methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and healthcare-associated bloodstream infections: Results of a quasi-experimental multicenter trial*

Spread of multidrug-resistant organisms within the intensive care unit (ICU) results in substantial morbidity and mortality. Novel strategies are needed to reduce transmission. This study sought to determine if the use of daily chlorhexidine bathing would decrease the incidence of colonization and bloodstream infections (BSI) because of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) among ICU patients. Six ICUs at four academic centers measured the incidence of MRSA and VRE colonization and BSI during a period of bathing with routine soap for 6 months and then compared results with a 6-month period where all admitted patients received daily bathing with a chlorhexidine solution. Changes in incidence were evaluated by Poisson and segmented regression modeling. Daily bathing with a chlorhexidine-containing solution. Acquisition of MRSA decreased 32% (5.04 vs. 3.44 cases/1000 patient days, p = 0.046) and acquisition of VREdecreased 50% (4.35 vs. 2.19 cases/1000 patient days, p = 0.008) following the introduction of daily chlorhexidine bathing. Segmented regression analysis demonstrated significant reductions in VRE bacteremia (p = 0.02) following the introduction of chlorhexidine bathing. VRE-colonized patients bathed with chlorhexidine had a lower risk of developing VRE bacteremia (relative risk 3.35; 95% confidence interval 1.13-9.87; p = 0.035), suggesting that reductions in the level of colonization led to the observed reductions in BSI. We conclude that daily chlorhexidine bathing among ICU patients may reduce the acquisition of MRSA and VRE. The approach is simple to implement and inexpensive and may be an important adjunctive intervention to barrier precautions to reduce acquisition of VRE and MRSA and the subsequent development of healthcare-associated BSI.