Methicillin-resistant S. Aureus Bloodstream Infection Research Articles

S. aureus Surveillance and Decolonization Associated with Decreased MRSA, but not MSSA, Infections in the Neonatal ICU

Background: Invasive Staphylococcus aureus infections cause significant morbidity and mortality in neonatal intensive care unit (NICU) infants.1 Colonization (asymptomatic carriage in the nose, skin, or gut) is a risk factor for subsequent invasive infection (e.g., pneumonia, bone infections, bloodstream infections, etc.). Active surveillance and decolonization measures for S. aureus-colonized infants have been associated with decreased invasive infection rates. 2-4 Methods: A methicillin-resistant S. aureus (MRSA) surveillance and decolonization program, consisting of admission and weekly MRSA nasal cultures followed by intranasal mupirocin plus chlorhexidine baths for colonized infants, was implemented in our level IV NICU with 150 beds in 2006.5 Due to poor compliance with decolonization protocols5, existing practices were reviewed and multiple interventions to increase compliance were implemented in 2018. These renewed efforts included revision of the existing MRSA decolonization protocol, updating the associated electronic medical record order set, re-education of unit staff, and weekly review by the Infection Prevention (IP) and NICU leadership teams to ensure the decolonization protocol was followed for newly colonized infants. Mean MRSA bloodstream infection (BSI) rates were calculated quarterly pre- (January 2014-December 2017) and post- (January 2018-December 2023) implementation of renewed efforts and compared via unpaired t-test. In July 2020 a similar methicillin-susceptible S. aureus (MSSA) surveillance and decolonization program was implemented with an associated revision of existing documents, education campaign, and weekly review of infants with new MSSA colonization. Mean MSSA BSI rates pre- (July 2018-June 2020) and post- (July 2020-December 2023) implementation were compared via unpaired t-test. Results: Renewed implementation of MRSA surveillance and decolonization was associated with a sustained decrease in the mean MRSA BSI rate (Figure 1): 0.10 per 1000 patient-days pre-implementation, 0.03 post-implementation (p=0.02). Following implementation of MSSA surveillance and decolonization, there was no statistically significant change in the mean MSSA BSI rate (Figure 2): 0.20 per 1000 patient-days pre-implementation, 0.15 post-implementation (p=0.32). Conclusions: Implementation of a robust MRSA surveillance and decolonization program in the NICU was associated with a sustained decrease in invasive MRSA infections. No change in invasive MSSA infection rates was observed following implementation of a similar protocol for MSSA. Additional research is needed to better understand the role of MSSA surveillance and decolonization in the NICU.

Staphylococcus aureus bloodstream infection in a Chinese tertiary-care hospital: A single-center retrospective study.

Staphylococcus aureus bloodstream infection in a Chinese tertiary-care hospital: A single-center retrospective study.

Increase in methicillin-susceptible Staphylococcus aureus bloodstream infections in Switzerland: a nationwide surveillance study (2008–2021)

PurposeAn increasing burden of Staphylococcus aureus bloodstream infections (BSI), despite a decrease in the percentage of methicillin-resistant S. aureus (MRSA), was described recently in other European countries. The main aim of this study was to analyse recent temporal trends of S. aureus, methicillin-susceptible S. aureus (MSSA) and MRSA BSI for Switzerland as well as the different linguistic regions within Switzerland. An additional aim was to estimate potential differences among patient-based and epidemiological risk factors.MethodsA retrospective observational study was conducted in Switzerland over a period of 14 years (2008–2021). Trends in S. aureus, MSSA and MRSA BSI were analysed by applying linear regression models.ResultsStaphylococcus aureus BSI increased by + 30% from 19.7 to 25.6 cases per 100,000 inhabitants between 2008 and 2021 (P < 0.01) in Switzerland. Thereof, MSSA increased by + 37% from 17.8 to 24.4 cases per 100,000 inhabitants (P < 0.01). MRSA decreased from 1.9 to 1.2 cases per 100,000 inhabitants (P < 0.01), which was driven by decreasing incidence in the French-speaking region. MSSA BSI increased significantly (P < 0.01) in both linguistic regions. A further stratification revealed that incidence increased the most in male patients of the age group ≥ 80 years of the German-speaking region.ConclusionThe increasing health burden of MSSA BSI in Switzerland indicates that not only proportions of resistant microorganisms but also total BSI incidences should be monitored. In addition, data stratification revealed that the increase was mainly driven by an increasing incidence in elderly males of the German-speaking region.

Everybody nose: molecular and clinical characteristics of nasal colonization during active methicillin-resistant Staphylococcus aureus bloodstream infection

BackgroundHealthcare-associated infections pose a potentially fatal threat to patients worldwide and Staphylococcus aureus is one of the most common causes of healthcare-associated infections. S. aureus is a common commensal pathogen and a frequent cause of bacteremia, with studies demonstrating that nasal and blood isolates from single patients match more than 80% of the time. Here we report on a contemporary collection of colonizing isolates from those with methicillin-resistant S. aureus (MRSA) bloodstream infections to evaluate the diversity within hosts, and detail the clinical features associated with concomitant nasal colonization.MethodsSwabs of the bilateral anterior nares were obtained from patients diagnosed with MRSA bacteremia. A single colony culture from the blood and an average of 6 colonies from the nares were evaluated for MRSA growth. For the nares cultures, we typed multiple isolates for staphylococcal protein A (spa) and derived the clonal complexes. Demographic and clinical data were obtained retrospectively from the electronic medical record system and analysed using univariate and multivariable regression models.ResultsOver an 11-month period, 68 patients were diagnosed with MRSA bloodstream infection, 53 were swabbed, and 37 (70%) were colonized with MRSA in the anterior nares. We performed molecular typing on 213 nasal colonies. Spa types and clonal complexes found in the blood were also detected in the nares in 95% of the cases. We also found that 11% of patients carried more than one clone of MRSA in the nares. Male sex and history of prior hospitalization within the past 90 days increased odds for MRSA colonization.ConclusionThe molecular epidemiological landscape of colonization in the setting of invasive disease is diverse and defining the interplay between colonization and invasive disease is critical to combating invasive MRSA disease.

Emerging Treatment Options for Acute Bacterial Skin and Skin Structure Infections and Bloodstream Infections Caused by Staphylococcus aureus: A Comprehensive Review of the Evidence.

Staphylococcus aureus remains an important human pathogen of concern, with mortality rates surpassing 30% in the case of severe systemic infections. Distinguishing methicillin-susceptible S. aureus from methicillin-resistant S. aureus (MRSA) is fundamental for therapeutic choices. A crucial emerging concept in the treatment of acute bacterial skin and skin structure infections is the availability of various approved agents with anti-MRSA activity, which allow a personalized approach based on the characteristics of any given patient while at the same time remaining in line with high certainty efficacy evidence from large randomized controlled trials. Regarding the treatment of S. aureus bloodstream infections (BSI), interesting aspects that may become relevant in the near future are the presence of both old and novel agents in phase-2 or phase-3 of clinical development for this indication, and the pressing need for high certainty evidence to guide the possible use of combination therapy in specific categories or phenotypes of patients with complicated MRSA BSI.

Bloodstream infections in older population: epidemiology, outcome, and impact of multidrug resistance

Bloodstream infections (BSIs) among older patients are frequent with high rate of mortality. Infections with multidrug-resistant organisms (MDRO) are associated with higher mortality than with susceptible microorganisms. We aimed to evaluate the prevalence of MDRO infection during BSI in older population and the factors associated with unfavorable outcome. This study is a retrospective cohort of all BSI episodes occurring among older patients (> 65yo), from April 1, 2010, to December 31, 2016, in a French university hospital for geriatric medicine. A total of 255 BSI episodes were analyzed. Mean age was 86.3±6.5 years, and sex ratio (M/F) was 0.96. Main comorbidities were orthopedic device (26.7%), active neoplasia (24.3%), and diabetes mellitus (18.4%). Main primary sites of infection were urinary tract infections (56.9%), respiratory tract infections (10.6%), intra-abdominal infections (7.1%), and skin and soft tissue infections (4.7%). Main bacteria identified were Escherichia coli (45.1%), Staphylococcus aureus (14.1%), enterococci (10.7%), coagulase-negative staphylococci (CoNS) (5.5%), and streptococci (5.1%). MDROs were involved in 17.2% of BSI (gram-negative bacilli: 9.0%; CoNS: 4.3%; and methicillin-resistant S. aureus (MRSA): 3.9%). The main factor associated with MDRO BSI was colonization with MDRO (OR=6.29; 95%CI=2.9-14.32). Total mortality was 18.4% and significantly higher in case of initial severity (OR=3.83; 95%CI=1.75-8.38), healthcare-associated infection (OR=5.29; 95%CI=1.11-25.30), and MRSA BSI (OR=9.16; 95%CI=1.67-50.16). BSI due to MDRO is frequent in older population and is strongly associated with carriage of MDRO. Healthcare-associated BSI, severe episodes, and BSI due to MRSA are associated with unfavorable outcome. In these cases, a broad-spectrum antibiotic should be promptly initiated.

282. Epidemiological Evaluation of Methicillin-Resistant Staphylococcus aureus (MRSA) and Methicillin-Susceptible Staphylococcus aureus (MSSA) Bacteremia: A Comprehensive Cancer Center’s 10-Year Experience

BackgroundCoagulase-positive Staphylococcus aureus bacteremia among cancer patients carries significant morbidity and mortality. This study aims to compare the risk factors and clinical outcomes among cancer patients diagnosed with bloodstream infection (BSI) with methicillin-sensitive S. aureus (MSSA) or methicillin-resistant S. aureus (MRSA).MethodsWe performed a retrospective cohort study on all patients diagnosed with an active solid tumor or hematologic cancer with positive blood culture for S. aureus from January 2009 to May 2019. We collected data on demographics, comorbidities, malignancy type, venous access, neutropenia status, echocardiogram results, treatment (tx) duration, antibiotics usage pre/post culture, hospital LOS, infection severity, and 7-day and 30-day mortality. We used the Chi-square test to analyze categorical variables, t-test to analyze continuous variables, and the Kaplan-Meier survival curve and multivariate regression to analyze mortality.ResultsTwo hundred eighty-three cases with malignancies and S. aureus BSIs were reviewed, and 168 were identified with BSIs for MRSA or MSSA during the ten years. The mean age for MRSA cases was 73.1 (±13.7) and 70.1 (± 14.6) for MSSA; male patients were most of the sex (P < 0.01). MRSA and MSSA bacteremia presented equally in hematologic malignancies, while MSSA was observed more in skin cancer than MRSA. Cancers that obstruct GU tracts may be associated with MRSA and MSSA from urine source as both were overrepresented in patients with bladder and rectal cancer. In most patients, the CVC was promptly removed and appropriate antibiotics were given promptly within 1 hour of the positive blood culture. For patients who underwent echocardiogram, most had a negative result in both groups. There was no significant difference for seven and 30-day mortality between the two groups. The mean hospital LOS was longer for MRSA cases (10.5 ± 13.5) versus MSSA cases (4.88 ± 9.1), (P < 0.01). Figures 1 & 2. Kaplan-Meier Survival Curve Comparing 7 and 30-day Mortality of Cancer Patients with MRSA vs MSSA BSI Figure 3 & 4. Distribution of Cancer Types for MRSA (n=84) and MSSA (n=84) BSI ConclusionEndocarditis with either MRSA or MSSA BSI is not a prominent finding among cancer patients at our institution. Given the extensive usage of CVCs and devices in patients with malignancies, prompt removal and antibiotic administration are essential to reduce morbidity; even then, the LOS for MRSA BSI remains longer than MSSA BSI.Disclosures All Authors: No reported disclosures

Moving Beyond Contact Precautions: Implementation of a Staphylococcus aureus Screening and Decolonization Program

Background:Staphylococcus aureus–colonized hospitalized patients are at risk for invasive infection and can transmit S. aureus to other patients in the absence of symptoms. Infection isolation precautions do not reduce the risk of infection in colonized patients and are untenable in health systems with high rates of S. aureus colonization. Objective: We implemented an inpatient S. aureus screening and targeted decolonization program across hospital campuses to reduce transmission and invasive infection. We screen and decolonize for methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) because MSSA makes up more than half of all S. aureus isolated from clinical cultures in our health system. Methods: All medicine, pediatrics, and transplant patients receive S. aureus nares culture at admission and upon change in level of care for medicine, and at admission and weekly for pediatrics and transplant patients. All S. aureus–colonized patients receive decolonization with nasal mupirocin ointment and chlorhexidine baths. Two implementation frameworks guide our processes for S. aureus screening and decolonization: the Consolidated Framework for Implementation Research, to evaluate factors affecting implementation at different levels of the health system, and the Dynamic Sustainability Framework, to account for iterative changes as the hospital setting and patient population change over time. Implementation interventions focus on education of patients and bedside nurses who perform S. aureus screening and decolonization; utilization of the electronic health record to identify patients for screening and/or decolonization and avoid human error; and introduction of a clinical nurse specialist to oversee the program and to provide iterative feedback. Results: At baseline, 21% of patients had S. aureus colonization, 20% of which was MRSA, and the MRSA bloodstream infection rate was 0.06 per 1,000 patient days. After program implementation, there was no change in S. aureus colonization and the MRSA bloodstream infection rate fell to 0.04 per 1,000 patient days. Screening compliance improved from 39% (N = 1,805) of eligible patients in the 6-month period before the introduction of the clinical nurse specialist to 52% (N = 2,024) after the introduction of the clinical nurse specialist. In the same periods, decolonization increased from 18.6% to 41% of eligible patients. Conclusions: We used 2 implementation frameworks to design our S. aureus screening and decolonization program and to make iterative changes to the program as it evolved to include new patient populations and different hospital settings. This resulted in a large-scale, sustainable, health system program for S. aureus control that avoids reliance on infection isolation precautions.Funding: NoneDisclosures: None

552. Within-Host Evaluation of Colonization During Active Methicillin-Resistant S. aureus Bacteremia

Background Staphylococcus aureus is a common commensal pathogen and a frequent cause of bacteremia, with nasal and blood isolates from single patients matching >80% of the time. Based on our prior work on paired single-patient isolates,1 our aim was to collect a contemporary set of colonizing isolates from those with methicillin-resistant S. aureus (MRSA) bloodstream infections (BSIs), evaluate the within-host diversity by whole-genome sequencing (WGS), and detail the clinical features linked to colonization.MethodsAdult patients with MRSA BSIs were screened for MRSA in the anterior nares from July 2018 to March 2019. Blood isolates underwent WGS, and spa and agr function screens were performed on three unique nasal isolates per patient. Clinical data from the electronic medical records underwent uni- and multivariate analyses on clinical features and outcomes.ResultsOf 55 unique patients with MRSA BSIs, screening of 45 subjects revealed that 67% were colonized with MRSA. The majority (64%) were males, 32% had prior colonization, and the most common infection sources were vascular access (27%), skin (24%), and unknown (24%). For those with nasal colonization, blood isolates were composed of 57% clonal complex (CC)5/t002, 33% CC8/t008, and 10% other. 81% of nasal isolates matched the blood, with 20% of nasal isolates harboring diverse spa types and 23% carried agr mutants. During this time frame, WGS found one transmission event involving a colonized subject. Colonization was associated with male gender (OR=4.52 95% CI [1.05–19.49]; P = 0.04) and prior hospital admission within the last 3 months (OR=6.12 95% CI [1.44–26.09]; P = 0.01) in multivariate analysis, with no differences in outcomes.ConclusionColonization is an important component of invasive MRSA disease, and we found high rates of colonization with a predominance of the CC5. We also noted significant diversity and high proportion of agr mutants. At-risk groups included males and those with prior hospitalization. Combined molecular and clinical analyses can define the intrahost and interhost transmission dynamics of MRSA, and enables the development of targeted approaches in order to curtail disease.1. Altman, D. R. et al. Genome Plasticity of agr-defective Staphylococcus aureus during clinical infection. Infect. Immun.(2018).Disclosures All authors: No reported disclosures.

Survival Benefit of Empirical Therapy for Staphylococcus aureus Bloodstream Infections in Infants.

The impact of early adequate empirical antibiotic therapy on outcomes of infants in the neonatal intensive care unit (NICU) who develop Staphylococcus aureus bloodstream infections (BSI) is unknown. Infants with S. aureus BSI discharged in 1997-2012 from 348 NICUs managed by the Pediatrix Medical Group were identified. Early adequate empirical antibiotic therapy was defined as exposure to ≥1 antibiotic with anti-staphylococcal activity on the day the first positive blood culture was obtained. All other cases were defined as inadequate empirical antibiotic therapy. We evaluated the association between inadequate empirical antibiotic therapy on outcomes controlling for gestational age, small for gestational age status, gender, discharge year, mechanical ventilation, inotropic support and use of supplemental oxygen. The primary outcome was 30-day mortality. Secondary outcomes were 7-day mortality, death before hospital discharge and length of bacteremia. Of the 3339 infants with S. aureus BSI, 2492 (75%) had methicillin-susceptible S. aureus (MSSA) BSI and 847 (25%) had methicillin-resistant S. aureus (MRSA) BSI. Inadequate empirical antibiotic therapy was administered in 725 (22%) cases. Inadequate empirical antibiotic therapy was associated with increased 30-day mortality (odds ratio: 2.03; 95% confidence interval: 1.08-3.82) among infants with MRSA BSI. Inadequate empirical antibiotic therapy was not associated with increases in mortality among infants with MSSA BSI. After controlling for confounders, inadequate empirical antibiotic therapy was associated with a modestly increased mortality at 30 days for infants with MRSA BSI.

Clinical outcomes and molecular typing of heterogenous vancomycin-intermediate Staphylococcus aureus bacteremia in patients in intensive care units.

BackgroundStaphylococcus aureus is one of most common pathogens in humans. Methicillin-resistant S. aureus (MRSA) accounts for 64 % of S. aureus bacteremia isolated in intensive care units (ICUs), and heteroresistant vancomycin-intermediates S. aureus (hVISA) is a phenotype of MRSA. However, studies focusing on the hVISA impact on critically ill patients are scarce.MethodsThis was a retrospective study conducted in a tertiary medical center from January 2009 to December 2010. All adult patients in ICUs with MRSA bloodstream infection were eligible. A modified population analysis profile and area under the curve method was applied to all isolates to confirm hVISA phenotype. Multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) and the accessory gene regulator (agr) typing were performed individually. Clinical outcomes including in-hospital mortality, length of stay in intensive care unit and hospital after MRSA bacteremia of the patients were also analyzed.ResultsA total of 48 patients were enrolled and 14 patients were confirmed to have the hVISA phenotype. The prevalence of hVISA was 29.2 %. There was no difference in the age, sex, comorbidity, Charlson’s comorbidity score and previous vancomycin therapy between the hVISA and VSSA groups. The hVISA group had a significantly higher in-hospital mortality than the VSSA group (13/14 versus 22/34; p = 0.046). All of the 14 hVISA patients had an MIC = 2 mg/L by E-test and this represented a significant association between high MIC and the development of hVISA (p < 0.001). MLST analysis showed all the isolates in the hVISA group were ST239, while ST239 (14/34; 41.2 %) and ST5 (12/34; 35.3 %) were predominant in the VSSA group (p = 0.007). A comparison of the survivor and non-survivor group showed that the hVISA phenotype (OR 11.8; 95 % CI 1.1–126.99; p = 0.042) and sequential organ failure assessment (SOFA) score (OR 1.39; 95 % CI 1.07–1.81; p = 0.014) were independent factors significantly associated with in-hospital mortality.ConclusionsPatients in ICUs with MRSA bacteremia may have a higher in-hospital mortality if they have the hVISA phenotype. SOFA score is also predictor of mortality.

Epidemiology of bloodstream infections caused by methicillin-resistant Staphylococcus aureus at a tertiary care hospital in New York

In the United States, bloodstream infections (BSIs) are predominated by Staphylococcus aureus. The proportion of community-acquired methicillin-resistant S aureus (MRSA) BSI is on the rise. The goal of this study is to explore the epidemiology of BSI caused by S aureus within Staten Island, New York. This is a case-case-control study from April 2012-October 2014. Cases were comprised of patients with BSI secondary to MRSA and methicillin-sensitive S aureus (MSSA). The control group contained patients who were hospitalized during the same time period as cases but did not develop infections during their stay. Two multivariable models compared each group of cases with the uninfected controls. A total of 354 patients were analyzed. Infections were community acquired in 76% of cases. The major source of BSI was skin-related infections (n = 76). The first multivariable model showed that recent central venous catheter placement was an independent infection risk factor (odds ratio [OR] = 80.7; 95% confidence interval [CI], 2.2-3,014.1). In the second model, prior hospital stay >3 days (OR = 4.1; 95% CI, 1.5-5.7) and chronic kidney disease (OR = 3.0; 95% CI, 1.01-9.2) were uniquely associated with MSSA. Persistent bacteremia, recurrence, and other hospital-acquired infections were more likely with MRSA BSI than MSSA BSI. Most infections were community acquired. The presence of a central venous catheter constituted a robust independent risk factor for MRSA BSI. Patients with MRSA BSI suffered worse outcomes than those with MSSA BSI.

Quantifying the matrix of relationships between reduced vancomycin susceptibility phenotypes and outcomes among patients with MRSA bloodstream infections treated with vancomycin.

Several phenotypic characteristics of Staphylococcus aureus have been identified as aetiological factors responsible for adverse outcomes among patients receiving vancomycin. However, characterization of the outcomes associated with these reduced vancomycin susceptibility phenotypes (rVSPs) remains largely incomplete and it is unknown if these features contribute to deleterious treatment outcomes alone or in concert. This study described the interrelationship between rVSPs and assessed their individual and combined effects on outcomes among patients who received vancomycin for a methicillin-resistant S. aureus (MRSA) bloodstream infection. An observational study of adult, hospitalized patients with MRSA bloodstream infections who were treated with vancomycin between January 2005 and June 2009 was performed. The rVSPs evaluated included the following: (i) Etest MIC; (ii) broth microdilution MIC; (iii) MBC : MIC ratio; and (iv) heteroresistance to vancomycin by the Etest macromethod. Failure was defined as any of the following: (i) 30 day mortality; (ii) bacteraemia ≥ 7 days on therapy; or (iii) recurrence of MRSA bacteraemia within 60 days of therapy discontinuation. During the study period, 184 cases met the study criteria and 41.3% met the failure criteria. There was a clear linear exposure-response relationship between the number of these phenotypic markers and outcomes. As the number of phenotypes escalated, the incidence of overall failure increased incrementally by 10%-18%. The data suggest that rVSPs contribute to deleterious treatment outcomes in concert.

Staphylococcus aureus bacteremia in an Indian tertiary care hospital: observational study on clinical epidemiology, resistance characteristics, and carriage of the Panton–Valentine leukocidin gene

To analyze the epidemiology and laboratory characteristics of Staphylococcus aureus bacteremia (SAB) in an Indian tertiary care hospital. We collected clinical, epidemiological, and laboratory data of all cases of SAB during August 2010 through July 2011. All isolates were tested for the Panton-Valentine leukocidin (PVL) gene. Eighteen percent of all blood stream infections (BSIs) were attributable to S. aureus. Among a total of 70 cases of SAB, 54% were due to methicillin-resistant S. aureus (MRSA) and 46% to methicillin-susceptible S. aureus (MSSA). Seventy-four percent of the cases had community-acquired (CA) SAB, among whom 69% had been hospitalized previously. Skin and soft tissue infections (SSTI) (30%) and respiratory infections (24%) were the common sources of bacteremia. The overall case fatality rate was 27%, and a similar percentage (23%) of patients discontinued therapy due to a poor medical outcome. The PVL gene was detected in 16% of S. aureus isolates, predominantly in CA-S. aureus (82%). SSTIs and pneumonia were the common sources of bacteremia in 45% of patients infected with a PVL-positive strain. S. aureus is a significant cause of BSI with a case fatality rate comparable to those of other developing nations. The upsurge in MRSA rates is alarming in our setup. Antibiotic stewardship and strict control of antibiotic use must be implemented by health care professionals to curb the increasing trend in MRSA BSIs.

The changing epidemiology of Staphylococcus aureus bloodstream infection: a multinational population-based surveillance study

Although the epidemiology of Staphylococcus aureus bloodstream infection (BSI) has been changing, international comparisons are lacking. We sought to determine the incidence of S. aureus BSI and assess trends over time and by region. Population-based surveillance was conducted nationally in Finland and regionally in Canberra, Australia, western Sweden, and three areas in each of Canada and Denmark during 2000–2008. Incidence rates were age-standardized and gender-standardized to the EU 27-country 2007 population. During 83 million person-years of surveillance, 18 430 episodes of S. aureus BSI were identified. The overall annual incidence rate for S. aureus BSI was 26.1 per 100 000 population, and those for methicillin-sensitive S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) were 24.2 and 1.9 per 100 000, respectively. Although the overall incidence of community-onset MSSA BSI (15.0 per 100 000) was relatively similar across regions, the incidence rates of hospital-onset MSSA (9.2 per 100 000), community-onset MRSA (1.0 per 100 000) and hospital-onset MRSA (0.8 per 100 000) BSI varied substantially. Whereas the overall incidence of S. aureus BSI did not increase over the study period, there was an increase in the incidence of MRSA BSI. Major changes in the occurrence of community-onset and hospital-onset MSSA and MRSA BSI occurred, but these varied significantly among regions, even within the same country. Although major changes in the epidemiology of community-onset and hospital-onset MSSA and MRSA BSIs are occurring, this multinational population-based study did not find that the overall incidence of S. aureus BSI is increasing.

Exzess-Letalität und -Verweildauer durch Blutstrominfektionen mit multiresistenten Erregern in Deutschland

Multiresistant pathogens cause substantial excess mortality and prolongation of hospital stay. However, until now there are no reliable estimates for Germany. Based on data of three recent publications from Europe and current German data on bloodstream infections because of methicillin-resistant S. aureus (MRSA) and extended spectrum beta-lactamase (ESBL) producing E. coli we calculated the number of patients dying from bloodstream infections because of MRSA- instead of methicillin-susceptible S. aureus (MSSA) or ESBL-producing E. coli instead of non-ESBL E. coli. About 421 patients died in 2010 because they suffered from MRSA bloodstream infection instead of MSSA bloodstream infection. Excess mortality for bloodstream infections because ESBL-producing E. coli instead of non-ESBL E. coli was about 256 cases. Considering that bloodstream infections with other multiresistant pathogens also lead to higher mortality, between 800 to 1000 deaths can be expected because of the resistant variant of the pathogens. In addition, bloodstream infections with multiresistant pathogens lead to more than 12000 additional days in hospital in Germany. Although this article does not include the burden of other healthcare-associated infections due to multiresistant pathogens the data for bloodstream infections alone demonstrate substantial excess burden and costs.

MRSA, screening and implications for the anaesthetist

MRSA, screening and implications for the anaesthetist

Antimicrobial therapy of Staphylococcus aureus bloodstream infection

Staphylococcus aureus bloodstream infection (BSI) contributes significantly to the morbidity and mortality of in-patients. The optimal therapy for methicillin-susceptible S. aureus BSI consists of penicillins. The efficacy of these drugs is well documented from several published data and supported from a long clinical experience. Methicillin-resistant S. aureus (MRSA) strains are responsible for the majority of nosocomial BSI and are recovered with increasing frequency at hospital admission. Although glycopeptides still represent the drugs of choice, there are several concerns on the treatment of MRSA BSI: reports of clinical failure with vancomycin treatment, regardless of the in vitro susceptibility; increasing reports of MRSA strains with reduced vancomycin susceptibility; difficulty in therapeutic dosage monitoring of teicoplanin; lack of evidence on the efficacy of combination therapy. Recently, new drugs have been introduced in the therapeutic arsenal for MRSA infections, but their clinical use is not yet clearly established for BSI. The review summarises evidence on present therapeutic options for the treatment of S. aureus BSI.

Clinical outcome and costs of nosocomial and community-acquired Staphylococcus aureus bloodstream infection in haemodialysis patients

The main aim of this study was to evaluate the clinical outcome and costs of nosocomial and community-acquired methicillin-susceptible Staphylococcus aureus (MSSA) or methicillin-resistant S. aureus (MRSA) bloodstream infection (BSI) in patients undergoing haemodialysis. A multicentre retrospective study was conducted that included 109 patients with end-stage renal disease and S. aureus BSI who were hospitalised in three German centres between 1999 and 2005. Nosocomial and community-acquired infections were analysed separately with regard to costs and outcome. Forty-nine (45%) patients had nosocomial infection. Compared to patients with community-acquired infection, these patients were more likely to have had BSI caused by MRSA (40.8% vs. 13.3%, p <0.05). BSI was the initial reason for admission for 33 (55%) patients who had community-acquired infection. The mean length of hospitalisation was 24 days for patients with community-acquired infection and 51 days for patients with nosocomial infection (p <0.05). Costs per treatment episode were 20,024 Euros for nosocomial infection vs. 9554 Euros for community-acquired infection (p <0.05). The average treatment costs for patients with MSSA BSI were <50% of those for patients with MRSA BSI (10,573 vs. 24,931 Euros, p <0.05). S. aureus BSI is an underlying cause of substantial health risk and high morbidity among the haemodialysis-dependent population, who are already at high-risk for other reasons. This study also highlighted differences according to the source of BSI, including costs arising from hospitalisation and treatment.

Hospital Mortality for Patients With Bacteremia Due to Staphylococcus aureus or Pseudomonas aeruginosa

To evaluate the relationship between hospital mortality and bloodstream infections due to Staphylococcus aureus or Pseudomonas aeruginosa. Prospective cohort study. A 1,400-bed, university-affiliated urban teaching hospital. Between December 2001 and September 2002, 314 patients with bacteremia due to S aureus or P aeruginosa were prospectively evaluated. Prospective patient surveillance and data collection. Thirteen patients (4.1%) received inadequate initial antibiotic treatment. Fifty-four patients (17.2%) died during hospitalization. Hospital mortality was statistically greater for patients with bloodstream infections due to P aeruginosa (n = 49) compared to methicillin-sensitive S aureus (MSSA) [n = 117; 30.6% vs 16.2%, p = 0.036] and methicillin-resistant S aureus (MRSA) [n = 148; 30.6% vs 13.5%, p = 0.007]. Multiple logistic regression analysis identified the lack of response to initial medical treatment (adjusted odds ratio [AOR], 2.69; 95% confidence interval [CI], 1.83 to 3.94; p = 0.010) and endocarditis (AOR, 4.62; 95% CI, 2.45 to 8.73; p = 0.016) as independent determinants of hospital mortality. Patients with bloodstream infections due to P aeruginosa were statistically more likely to be nonresponders to early medical treatment compared to patients with MSSA (73.5% vs 11.1%, p < 0.001) and MRSA (73.5% vs 16.9%, p < 0.001) bloodstream infections. These data suggest that bloodstream infections due to P aeruginosa have a greater risk of hospital mortality compared to bloodstream infections due to S aureus despite adequate antibiotic treatment.