Clinical management of Staphylococcus aureus bacteremia: a review

Diagnosis and treatment of catheter-related bloodstream infection: Clinical guidelines of the Spanish Society of Infectious Diseases and Clinical Microbiology and (SEIMC) and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units (SEMICYUC)

Catheter-related bloodstream infections (CRBSI) constitute an important cause of hospital-acquired infection associated with morbidity, mortality, and cost. The aim of these guidelines is to provide updated recommendations for the diagnosis and management of CRBSI in adults. Prevention of CRBSI is excluded. Experts in the field were designated by the two participating Societies (the Spanish Society of Infectious Diseases and Clinical Microbiology and [SEIMC] and the Spanish Society of Spanish Society of Intensive and Critical Care Medicine and Coronary Units [SEMICYUC]). Short-term peripheral venous catheters, non-tunneled and long-term central venous catheters, tunneled catheters and hemodialysis catheters are covered by these guidelines. The panel identified 39 key topics that were formulated in accordance with the PICO format. The strength of the recommendations and quality of the evidence were graded in accordance with ESCMID guidelines. Recommendations are made for the diagnosis of CRBSI with and without catheter removal and of tunnel infection. The document establishes the clinical situations in which a conservative diagnosis of CRBSI (diagnosis without catheter removal) is feasible. Recommendations are also made regarding empirical therapy, pathogen-specific treatment (coagulase-negative staphylococci, Staphylococcus aureus, Enterococcus spp., Gram-negative bacilli, and Candida spp.), antibiotic lock therapy, diagnosis and management of suppurative thrombophlebitis and local complications.

18F-FDG PET/CT-Guided Treatment Duration in Patients with High-Risk Staphylococcus Aureus Bacteremia: A Proof of Principle

Current guidelines recommend intravenous antibiotic therapy for at least 4 wk in patients with high-risk Staphylococcus aureus bacteremia (SAB), because of the risk for metastatic infection. We evaluated the safety of a shorter duration of treatment in patients with high-risk SAB without signs of metastatic infection at presentation, using standard ¹⁸F-FDG PET/CT and echocardiography. Methods: Retrospective analyses were performed of patients with SAB admitted between 2013 and 2017 in 2 medical centers. Patients with risk factors for complicated bacteremia (community acquisition, persistently positive blood cultures, >72 h of fever, or foreign body materials present), a normal echocardiography result, and ¹⁸F-FDG PET/CT without signs of metastatic infection were included (cases) and compared with patients with uncomplicated bacteremia (absence of any of the risk factors and no known metastatic disease, controls). Primary outcomes were 3-mo SAB-specific mortality rate and recurrent infection. The secondary outcome was overall mortality. Results: We included 36 cases and 40 controls. Both groups had a similar treatment duration (15.9 vs. 15.4 d). No deaths occurred as a consequence of SAB in the cases, compared with 1 in the control group. One relapse occurred in the case group and 2 in the control group. Overall mortality did not differ between the groups (19.4% vs. 15.0%, P = 0.64). Conclusion: This study suggests that intravenous treatment for 2 wk in high-risk patients with SAB without endocarditis and absence of metastatic infection on ¹⁸F-FDG PET/CT is safe. A diagnostic-driven approach using ¹⁸F-FDG PET/CT to determine treatment duration in high-risk SAB seems feasible and allows tailoring treatment to individual patients.

Enhanced topical delivery of non-complexed molecular iodine for Methicillin-resistant Staphylococcus aureus decolonization

Staphylococcus aureus, a leading cause of serious human infections in both healthcare and community settings, is increasingly difficult to control due to expanding resistance to multiple antibiotic classes. Methicillin-resistant S. aureus (MRSA) strains have disseminated on a global scale and are associated with adverse patient outcomes, increased hospital stays, and significant economic costs to the healthcare system. A proximal step in S. aureus infection is colonization of the nasal mucosa, and effective strategies to decolonize high risk patients to reduce the risk of invasive infection and nosocomial spread represent an important clinical priority. With rising resistance to mupirocin, the most common antibiotic utilized for nasal MRSA decontamination, we are examining the use of pure molecular iodine (I₂)-based formulations for this indication. Recently, an iodophor formulation of povidone-iodine (PVP-I) has shown significant promise for nasal MRSA decontamination by swabbing the anterior nares of patients in hospital settings, but the I₂ concentration in this treatment is less than 0.01% of total iodine species present and like all providone-iodine formulations causes skin staining. Here we determine that a novel non-staining formulation of I₂ combined with the safe organic emollient glycerin delivers high local concentrations of the active antimicrobial entity (I₂) with minimal evaporative loss, exhibits activity at ∼1 part per million against MRSA and other important Gram-positive and -negative human pathogens. This formulation for I₂ topical delivery produced similar reductions in mean bacterial burden and was associated with fewer treatment failures (<2-logfold reduction) than PVP-I in a murine model of MRSA nasal decontamination. Formulations of I₂ in glycerin emollient merit further exploration as topical disinfectants for human medical indications.

Impact of antimicrobial treatment duration on outcome of Staphylococcus aureus bacteraemia: a cohort study

OBJECTIVES

To assess the outcome of Staphylococcus aureus bacteraemia (SAB) according to factors associated with necessity for longer treatment in conjunction with the duration of treatment.

METHODS

We prospectively collected the data of patients with SAB consecutively during 12 to 39 months from 11 hospitals. If multiple episodes of SAB occurred in one patient, only the first episode was enrolled. Factors associated with necessity for longer treatment were defined as follows: persistent bacteraemia, metastatic infection, prosthesis and endocarditis. If any of the factors were present, then the case was defined as longer antibiotic treatment warranted (LW) group; those without any factors were defined as shorter antibiotic treatment sufficient (SS) group. Poor outcome was defined as a composite of 90-day mortality or 30-day recurrence. Duration of antibiotic administration was classified as <14 or ≥14 days in the SS group and <28 or ≥28 days in the LW group.

RESULTS

Among 2098 cases, the outcome was analysed in 1866 cases, of which 591 showed poor outcome. The SS group accounted for 964 cases and the LW group for 852. On multivariate analysis, age over 65 years, pneumonia, higher Sequential Organ Failure Assessment (SOFA) score and chronic liver diseases were risk factors for poor outcome. Administration of antibiotics less than the recommendation was associated with poor outcome, but this significance was observed only in the LW group (adjusted odds ratio = 1.68; 95% confidence interval, 1.00-2.83; p 0.05).

CONCLUSIONS

Inappropriately short antibiotic treatment was associated with poor outcome in the LW group. Vigilant evaluation for risk factors to determine the duration of treatment may improve the outcome among patients with SAB.

Effect of Algorithm-Based Therapy vs Usual Care on Clinical Success and Serious Adverse Events in Patients with Staphylococcal Bacteremia: A Randomized Clinical Trial

IMPORTANCE

The appropriate duration of antibiotics for staphylococcal bacteremia is unknown.

OBJECTIVE

To test whether an algorithm that defines treatment duration for staphylococcal bacteremia vs standard of care provides noninferior efficacy without increasing severe adverse events.

DESIGN, SETTING, AND PARTICIPANTS

A randomized trial involving adults with staphylococcal bacteremia was conducted at 16 academic medical centers in the United States (n = 15) and Spain (n = 1) from April 2011 to March 2017. Patients were followed up for 42 days beyond end of therapy for those with Staphylococcus aureus and 28 days for those with coagulase-negative staphylococcal bacteremia. Eligible patients were 18 years or older and had 1 or more blood cultures positive for S aureus or coagulase-negative staphylococci. Patients were excluded if they had known or suspected complicated infection at the time of randomization.

INTERVENTIONS

Patients were randomized to algorithm-based therapy (n = 255) or usual practice (n = 254). Diagnostic evaluation, antibiotic selection, and duration of therapy were predefined for the algorithm group, whereas clinicians caring for patients in the usual practice group had unrestricted choice of antibiotics, duration, and other aspects of clinical care.

MAIN OUTCOMES AND MEASURES

Coprimary outcomes were (1) clinical success, as determined by a blinded adjudication committee and tested for noninferiority within a 15% margin; and (2) serious adverse event rates in the intention-to-treat population, tested for superiority. The prespecified secondary outcome measure, tested for superiority, was antibiotic days among per-protocol patients with simple or uncomplicated bacteremia.

RESULTS

Among the 509 patients randomized (mean age, 56.6 [SD, 16.8] years; 226 [44.4%] women), 480 (94.3%) completed the trial. Clinical success was documented in 209 of 255 patients assigned to algorithm-based therapy and 207 of 254 randomized to usual practice (82.0% vs 81.5%; difference, 0.5% [1-sided 97.5% CI, -6.2% to ∞]). Serious adverse events were reported in 32.5% of algorithm-based therapy patients and 28.3% of usual practice patients (difference, 4.2% [95% CI, -3.8% to 12.2%]). Among per-protocol patients with simple or uncomplicated bacteremia, mean duration of therapy was 4.4 days for algorithm-based therapy vs 6.2 days for usual practice (difference, -1.8 days [95% CI, -3.1 to -0.6]).

CONCLUSIONS AND RELEVANCE

Among patients with staphylococcal bacteremia, the use of an algorithm to guide testing and treatment compared with usual care resulted in a noninferior rate of clinical success. Rates of serious adverse events were not significantly different, but interpretation is limited by wide confidence intervals. Further research is needed to assess the utility of the algorithm.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01191840.

The Use of Liquids Ionic Fluids as Pharmaceutically Active Substances Helpful in Combating Nosocomial Infections Induced by Klebsiella Pneumoniae New Delhi Strain, Acinetobacter Baumannii and Enterococcus Species

This review deals with various microbiological activities of ionic liquids, which constitute the first anti-infective defense against multi-drug-resistant bacteria-with a particular emphasis placed on medicine and pharmacology. The quoted data on the biological activity of ionic liquids including their antimicrobial properties (depending on the type of a cation or an anion) and are discussed in view of possible applications in nosocomial infections. Dedicated attention is given to finding infections with the Klebsiella pneumoniae New Delhi strain, Acinetobacter baumannii, and Enterococcus species, which are responsible for the induction of antibiotic resistance in intensive care units. Diagnosis and treatment using current antibiotics is a significant problem in hospital care, and the relevant burden on the health systems of the European Union member states induces the search for new, effective methods of treatment. Ionic liquids, due to their antibacterial effect, can be considered topical and general medications and may provide the basis for treatment to eliminate the antibiotic resistance phenomenon in the future. At present, the number of infections with resistant pathogens in hospitals and outpatient clinics in the European Union is growing. In 2015⁻2017, a significant incidence of respiratory and bloodstream infections with bacteria resistant to antibiotics from the 3rd generation group of cephalosporins, glycopeptides, and carbapenems were observed. The paper presents examples of synthesized bifunctional salts with at least one pharmaceutically active ion in obtaining a controlled release, controlled delivery, and biological impact on the pathogenic bacteria, viruses and fungi. The ionic liquids obtained in the presented way may find applications in the treatment of wounds and infections.

The DENOVA score efficiently identifies patients with monomicrobial Enterococcus faecalis bacteremia where echocardiography is not necessary

OBJECTIVES

Enterococcal bacteremia can be complicated by infective endocarditis (IE) and when suspected, transesophageal echocardiography (TEE) should be performed. The previously published NOVA score can identify patients with enterococcal bacteremia at risk for IE and we aimed to improve the score.

METHODS

Factors associated with IE were studied retrospectively in a population-based cohort of patients with monomicrobial Enterococcus faecalis bacteremia (MEFsB). Factors associated with IE in multivariable analysis were included in a new score system which was compared to the NOVA score and validated in a cohort of patients with MEFsB from another region.

RESULTS

Among 397 episodes of MEFsB, 44 episodes with IE were compared to those without IE. Long Duration of symptoms (≥ 7 days) and Embolization were associated with IE in the multivariate analysis and hence were added to the NOVA variables (Number of positive cultures, Origin of infection unknown, Valve disease, and Auscultation of murmur) to generate a novel score; DENOVA. The area under the curve in ROC analyses was higher for DENOVA (0.95) compared to NOVA (0.91) (p = 0.001). With a cutoff at ≥ 3 positive variables the DENOVA score has a sensitivity of 100% and specificity of 83% which is superior to the NOVA score (specificity 29%). The DENOVA score was applied to the validation cohort (26 IE episodes and 256 non-IE episodes) and the resulting sensitivity was 100% and the specificity was 85% compared to 35% for NOVA.

CONCLUSIONS

The DENOVA score is a useful tool to identify patients with MEFsB where TEE is not needed.

Influence of GeneXpert MRSA/SA test implementation on clinical outcomes of Staphylococcus aureus bacteremia - a before-after retrospective study

Use of GeneXpert MRSA/SA in diagnostic algorithms of Staphylococcus aureus bacteremia may influence both patients' clinical outcomes and antibiotic stewardship. We evaluated these outcomes in a retrospective cohort before (1/6/2015-31/5/2016) and after (1/6/2016-31/8/2017) the introduction of the test in adult patients with Gram-positive cocci in clusters in blood cultures. We included 254 patients (125 preintervention, 129 postintervention). No significant difference in 30-day mortality or clinical success was demonstrated between periods. Appropriate antibiotic therapy rates were significantly higher in the postintervention group, and vancomycin use was significantly reduced (80.6% vs 53.6%, P < 0.01; 2.3±0.38 vs 2.98±1.02 defined daily doses/100 patient days, P = 0.026, respectively). Appropriate beta-lactam use was also significantly higher (56.7% postintervention vs 23.1% preintervention, P < 0.01). Use of GeneXpert MRSA/SA test has a positive effect on antibiotic stewardship measures, though it has no significant effect on clinical outcomes including mortality in this fatal infection.

Natural Cyclic Peptides as an Attractive Modality for Therapeutics: A Mini Review

Peptides are important biomolecules which facilitate the understanding of complex biological processes, which in turn could be serendipitous biological targets for future drugs. They are classified as a unique therapeutic niche and will play an important role as fascinating agents in the pharmaceutical landscape. Until now, more than 40 cyclic peptide drugs are currently in the market, and approximately one new cyclopeptide drug enters the market annually on average. Interestingly, the majority of clinically approved cyclic peptides are derived from natural sources, such as peptide antibiotics and human peptide hormones. In this report, the importance of cyclic peptides is discussed, and their role in drug discovery as interesting therapeutic biomolecules will be highlighted. Recently isolated naturally occurring cyclic peptides from microorganisms, sponges, and other sources with a wide range of pharmacological properties are reviewed herein.

No effects without causes: the Iron Dysregulation and Dormant Microbes hypothesis for chronic, inflammatory diseases

Since the successful conquest of many acute, communicable (infectious) diseases through the use of vaccines and antibiotics, the currently most prevalent diseases are chronic and progressive in nature, and are all accompanied by inflammation. These diseases include neurodegenerative (e.g. Alzheimer's, Parkinson's), vascular (e.g. atherosclerosis, pre-eclampsia, type 2 diabetes) and autoimmune (e.g. rheumatoid arthritis and multiple sclerosis) diseases that may appear to have little in common. In fact they all share significant features, in particular chronic inflammation and its attendant inflammatory cytokines. Such effects do not happen without underlying and initially 'external' causes, and it is of interest to seek these causes. Taking a systems approach, we argue that these causes include (i) stress-induced iron dysregulation, and (ii) its ability to awaken dormant, non-replicating microbes with which the host has become infected. Other external causes may be dietary. Such microbes are capable of shedding small, but functionally significant amounts of highly inflammagenic molecules such as lipopolysaccharide and lipoteichoic acid. Sequelae include significant coagulopathies, not least the recently discovered amyloidogenic clotting of blood, leading to cell death and the release of further inflammagens. The extensive evidence discussed here implies, as was found with ulcers, that almost all chronic, infectious diseases do in fact harbour a microbial component. What differs is simply the microbes and the anatomical location from and at which they exert damage. This analysis offers novel avenues for diagnosis and treatment.

Epidemiology and Outcomes of Infectious Spondylodiscitis in Hemodialysis Patients

STUDY DESIGN

A retrospective study of patients who were hospitalized for infectious spondylodiscitis over a 13-year period.

OBJECTIVE

To elucidate the epidemiology and prognostic factors of infectious spondylodiscitis in hemodialysis (HD) patients and to identify the impact of HD on infectious spondylodiscitis.

SUMMARY OF BACKGROUND DATA

Only a few case studies of infectious spondylodiscitis in HD patients can be found in the literature. Reports of prognostic factors are limited and patients' outcomes have not been well described.

METHODS

The cases of 1402 patients who were hospitalized for infectious spondylodiscitis over a 13-year period were retrospectively reviewed. Of these, 102 patients on maintenance HD were enrolled in this study. Cox proportional hazard model was used to evaluate the risk factors of mortality and recurrence.

RESULTS

The 102 enrolled patients had an average age 63.3 ± 11.2 years old and male-to-female ratio of 1:1.04. Back pain was present in 75.5% of patients and the most commonly infected site was the lumbosacral spine. Infection associated with vascular access was identified in 31.4% of patients. The prevalence of dialysis via central venous catheters was higher than prevalent HD patients. Methicillin-resistant Staphylococcus aureus was the most common pathogen, followed coagulase-negative staphylococci. The patients' in-hospital survival rate was 82.4%; their vascular access survival rate was 75.5%; their 1-year survival rate was 78.4%, and their 1-year recurrence rate was 20.2%. Congestive heart failure was associated with an increased 1-year mortality. Other variables exhibited no significant relationship with patients' in-hospital mortality, 1-year mortality or recurrence.

CONCLUSION

The characteristics and outcomes of infectious spondylodiscitis in HD patients were elucidated. Most of the demographic and clinical variables, evaluated upon admission, did not predict mortality or recurrence.

LEVEL OF EVIDENCE

3.

Onset of symptoms, diagnostic confirmation, and occurrence of multiple infective foci in patients with Staphylococcus aureus bloodstream infection: a look into the order of events and potential clinical implications

PURPOSE

Data on the systemic dissemination in Staphylococcus aureus bloodstream infection (SAB) remain sparse. We investigated the timing and the sequence of clinical symptoms, diagnostic confirmation, and occurrence of multiple infective foci in relation to three major infective foci.

METHODS

From 2006 to 2011, all adult patients with first-time SAB in Cologne and Freiburg, Germany were followed prospectively. The study was restricted to patients with short-term central venous catheter (CVC)-related SAB, vertebral osteomyelitis (VO), and infective endocarditis (IE). The collection date of the first positive blood culture was used as reference point for determining time to onset of clinical symptoms, microbiological findings, imaging results compatible with focal infection, and occurrence of additional infective foci.

RESULTS

We included 266 patients with first-time SAB. Among patients with CVC-related SAB, clinical onset, collection of the first positive blood culture, and microbiological confirmation almost coincided. In contrast, among patients with VO or IE, the onset of clinical symptoms most often preceded the collection of the first positive blood culture, and imaging and microbiological confirmation were most frequently obtained subsequent to the SAB diagnosis. CVC-related SAB was infrequently associated with further foci (n = 15/15.5%). Conversely, more than one infective focus was observed in 44 (56.4%) patient with VO and 68 (64.8%) patients with IE.

CONCLUSIONS

The sequence of clinical symptoms, diagnostic confirmation, and occurrence of multiple infective foci varied considerably with different infective foci in SAB. Based on these results, we propose a pragmatic and evidence-based terminology for the clinical course of SAB and suggest the terms "portal of entry", "infective focus", "multiple infective foci", and "dominant infective focus".

Association of Infectious Disease Consultation With Clinical Outcomes in Patients With Staphylococcus aureus Bacteremia at Low Risk for Endocarditis

Infectious disease (ID) consultation in patients with Staphylococcus aureus bacteremia who were at low risk for endocarditis and who had no secondary site of infection was associated with a longer course of antibiotics (median duration of intravenous antimicrobial therapy of 31 days and 15 days in those with and without ID consultation, respectively; P ≤ .01), and based on Kaplan-Meier survival analysis, reduced in-hospital mortality (P = .2), and reduced 30-day mortality after discharge (P = .4). ID consultation was also associated with a higher readmission rate within 90 days of discharge: 46% and 34% with and without ID consultation, respectively (P = .2).

The management and outcomes of Staphylococcus aureus bacteraemia at a South African referral hospital: A prospective observational study

OBJECTIVES

Data on the management and outcomes of Staphylococcus aureus bacteraemia (SAB) in resource-limited settings are limited. The aim of this study was to describe a cohort of South African patients with SAB, and explore the factors associated with complicated infection and death.

METHODS

This was a prospective observational study of patients over the age of 13 years admitted to a South African referral hospital with SAB.

RESULTS

One hundred SAB infection episodes occurring in 98 patients were included. SAB was healthcare-associated in 68.4%; 24.0% of all cases were caused by methicillin-resistant S. aureus (MRSA). Ninety-day mortality was 47.0%, with 83.3% of deaths attributable to SAB. There was a trend towards increased 90-day mortality with MRSA infection (odds ratio (OR) 1.28, 95% confidence interval (CI) 1.0-15.1) and the presence of comorbidities (OR 4.1, 95% CI 1.0-21.6). The risk of complicated infection was higher with non-optimal definitive antibiotic therapy (OR 8.5, 95% CI 1.8-52.4), female sex (OR 3.8, 95% CI 1.1-16.3), and community-acquired infection (OR 7.4, 95% CI 2.0-33.1). Definitive antibiotic therapy was non-optimal in 22.6% of all cases.

CONCLUSIONS

SAB-related mortality was high. A large proportion of cases may be preventable, and there is a need for improved antibiotic management.

Serious life-threatening multifocal infection in a child, caused by Panton-Valentine leucocidin-producing Staphylococcus aureus (PVL-MSSA)

Groin pain is a frequently occurring complaint in presentations to the Emergency Department. Muscular sprain is often a differential diagnosis, however serious conditions such as pyomyositis should not be ignored. This case report presents a child with atraumatic right groin pain, which was initially diagnosed as a muscular sprain. The patient later re-presented out of hours to the Emergency Department with what was found to be extensive pelvic abscesses. He was subsequently found to have bilateral pneumonia and later developed a pericardial effusion and osteomyelitis of the right iliac bone, sacroiliac joint and sacrum. With multiple surgical interventions and appropriate antibiotics, he made a full recovery and was discharged home after a total admission time of 41 days. The causative organism was found to be Panton-Valentine leucocidin-positive methicillin-susceptible Staphylococcus aureus.

Challenges in Estimating Characteristics of Staphylococcus aureus Nasal Carriage Among Humans Enrolled in Surveillance Studies

Evaluating carriage of Staphylococcus aureus, an opportunistic pathogen of humans and animals capable of causing antibiotic-resistant infections, is epidemiologically important. However, clinical and epidemiological surveillance studies of S. aureus typically rely on characterizing one isolate per individual, which may not represent the actual population diversity in a carrier. The objective of this study was to determine if one isolate is sufficient for determining carrier status of particular strains or characteristics of S. aureus in a healthy (non-hospitalized) human population. We compared spa types, genetic markers (mecA, scn), and antibiotic resistance profiles of 10 S. aureus isolates recovered from a single nasal swab for each of 19 participants (190 isolates total) selected from a cohort of industrial hog operation workers and their household members. Participants included both persistent (n = 10) and intermediate (n = 9) carriers of S. aureus. Among the participants, 17 (89%) carried a single S. aureus spa type intranasally and the other two carried dominant spa types. Less similarity was observed for genes encoded on mobile genetic elements (mecA, scn) and antibiotic resistance profiles. Statistical modeling, based on receiving operating characteristic curves, suggests that three to five isolates may be necessary to accurately assign nasal carriage status for these more variable characteristics. Variability was observed for both persistent and intermediate carriers of S. aureus. These results suggest that surveillance studies that rely on testing one S. aureus isolate are likely to identify predominant spa types but may not fully capture more variable characteristics of S. aureus, including antibiotic resistance. Surveillance studies that rely on testing one isolate may underestimate prevalence of nasal carriage of S. aureus with these more variable characteristics.

Implementing a hospital-wide protocol for Staphylococcus aureus bacteremia

Staphylococcus aureus bacteraemia (SAB) is associated with high-mortality and complication rates. A multidisciplinary approach is needed to predict, detect and treat complications. In this pre- and post-intervention study, we investigated the effects of a hospital-wide protocol for diagnosis, classification and treatment of SAB. It was hypothesized that complications and endocarditis would be better identified and treated. Medical records of SAB patients admitted in 2011 and 2012 (pre) were analysed. In 2013, a protocol, describing risk factors, diagnostic classification and recommended treatment, was implemented. In 2014 and 2015 (post), SAB patients were followed prospectively. Transthoracic (TTE) or transoesophageal cardiac ultrasound (TEE) was chosen following a decision tree. A resident internal medicine acted as contact person. Pre-intervention, 98 patients were eligible for analysis compared to 85 patients post-intervention. Age and number of risk factors were slightly higher post-intervention; other baseline characteristics were similar. Most SAB-patients were classified as complicated (89 and 82% pre- and post-intervention, respectively). Follow-up blood cultures drawn within 2 days after initiating treatment increased from 51 to 85%. Cardiac ultrasounds increased from 44 to 83% for TTE and 13 to 24% for TEE. Endocarditis was more frequently diagnosed (4 vs. 12%). Additionally, duration of antibiotic therapy increased. The 3-month mortality did not change significantly (33% pre-intervention vs. 35% post-intervention; p > 0.05). Introduction of a hospital-wide protocol for SAB management increased standard of care, created awareness among clinicians to properly classify SAB, search for endocarditis and adapt duration of antibiotic treatment. Mortality did not decrease.

Expression of HLA-DRA and CD74 mRNA in whole blood during the course of complicated and uncomplicated Staphylococcus aureus bacteremia

To improve management of Staphylococcus aureus bacteremia (SAB), better understanding of host-pathogen interactions is needed. In vitro studies have shown that S. aureus bacteria induce dose-dependent immunosuppression that is evidenced by reduced expression of major histocompatibility complex (MHC) class II on antigen presenting cells. Thus, the aim of this study was to determine whether expression of the MHC class II-related genes HLA-DRA and CD74 is more greatly reduced in complicated SAB, with its probable higher loads of S. aureus, than in uncomplicated SAB. Adult patients with SAB were prospectively included and blood samples taken on the day of confirmation of SAB (Day 1) and on Days 2, 3, 5 and 7. HLA-DRA and CD74 mRNA expression was determined by quantitative reverse transcription PCR. Sepsis was defined according to the Sepsis-3 classification and SAB was categorized as complicated in patients with deep-seated infection and/or hematogenous seeding. Twenty patients with SAB were enrolled and samples obtained on all assessment days. HLA-DRA and CD74 expression did not differ significantly between patients with SAB and sepsis (n = 13) and those without sepsis (n = 7) on any assessment day. However, patients with complicated SAB (n = 14) had significantly weaker HLA-DRA expression on all five assessment days than patients with uncomplicated SAB (n = 6). Additionally, they tended to have weaker CD74 expressions. Neutrophil, monocyte and leukocyte counts did not differ significantly between complicated and uncomplicated SAB. In conclusion, patients with complicated SAB show weaker HLA-DRA expression than those with uncomplicated SAB during the first week of bacteremia.

Methicillin-resistant Staphylococcus aureus bacteremia among liver transplant recipients: epidemiology and associated risk factors for morbidity and mortality

Bacteremia due to Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), complicates the clinical course of liver transplantation and is associated with high morbidity and mortality. Intravascular catheters had been reported to be the most frequent source of MRSA bacteremia. Among bacteremic liver recipients, 26.3%-100% of S. aureus were MRSA. Previous studies identified pre-transplant and post-transplant acquired S. aureus carriage, greater severity of liver disease, hepatocellular carcinoma and infection with immuno-modulatory viruses as predictors of S. aureus bacteremia in liver recipients. MRSA bacteremia accompanied by pneumonia and abdominal infections was related to mortality. Vancomycin, as well as daptomycin, is a first-line antibiotic for MRSA bacteremia. The purpose of this review is to better understand the characteristics of MRSA bacteremia by summarizing the epidemiology and antimicrobial resistance of S. aureus, the primary source, and related risk factors for morbidity and mortality of MRSA bacteremia. We have also explored the diagnostic, therapeutic and preventive measures for MRSA bacteremia to improve the outcomes of liver recipients.

Targeting fundamental pathways to disrupt Staphylococcus aureus survival: clinical implications of recent discoveries

The emergence of community-associated methicillin-resistant Staphylococcus aureus during the past decade along with an impending shortage of effective antistaphylococcal antibiotics have fueled impressive advances in our understanding of how S. aureus overcomes the host environment to establish infection. Backed by recent technologic advances, studies have uncovered elaborate metabolic, nutritional, and virulence strategies deployed by S. aureus to survive the restrictive and hostile environment imposed by the host, leading to a plethora of promising antimicrobial approaches that have potential to remedy the antibiotic resistance crisis. In this Review, we highlight some of the critical and recently elucidated bacterial strategies that are potentially amenable to intervention, discuss their relevance to human diseases, and address the translational challenges posed by current animal models.

The clinical significance of concomitant bacteriuria in patients with Staphylococcus aureus bacteremia. A review and meta-analysis

BACKGROUND

Staphylococcus aureus bacteriuria (SABU) concomitant to S. aureus bacteremia (SAB) has been associated with deep-seated infections and worse prognosis. However, the relevant studies were small and inconsistent. Here, we aim to provide a review of the relevant literature, and a meta-analysis of these studies.

METHODS

We searched PubMed and Scopus for studies comparing patients with SAB and concomitant SABU to patients with SAB without SABU.

RESULTS

Nine relevant studies were identified, involving 1429 patients with SAB, of whom 18.5% (n = 265) had concomitant SABU. Pooling the results of those studies, SABU was significantly associated with endocarditis, bone/joint infection and septic embolism. SABU was also associated with persistent SAB, and higher mortality.

CONCLUSIONS

Although SABU may be a useful marker of complicated SAB, the current literature has several limitations. Larger prospective studies are required to clarify the value of SABU in clinical decision making.

Adjunctive rifampicin for Staphylococcus aureus bacteraemia (ARREST): a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUND

Staphylococcus aureus bacteraemia is a common cause of severe community-acquired and hospital-acquired infection worldwide. We tested the hypothesis that adjunctive rifampicin would reduce bacteriologically confirmed treatment failure or disease recurrence, or death, by enhancing early S aureus killing, sterilising infected foci and blood faster, and reducing risks of dissemination and metastatic infection.

METHODS

In this multicentre, randomised, double-blind, placebo-controlled trial, adults (≥18 years) with S aureus bacteraemia who had received ≤96 h of active antibiotic therapy were recruited from 29 UK hospitals. Patients were randomly assigned (1:1) via a computer-generated sequential randomisation list to receive 2 weeks of adjunctive rifampicin (600 mg or 900 mg per day according to weight, oral or intravenous) versus identical placebo, together with standard antibiotic therapy. Randomisation was stratified by centre. Patients, investigators, and those caring for the patients were masked to group allocation. The primary outcome was time to bacteriologically confirmed treatment failure or disease recurrence, or death (all-cause), from randomisation to 12 weeks, adjudicated by an independent review committee masked to the treatment. Analysis was intention to treat. This trial was registered, number ISRCTN37666216, and is closed to new participants.

FINDINGS

Between Dec 10, 2012, and Oct 25, 2016, 758 eligible participants were randomly assigned: 370 to rifampicin and 388 to placebo. 485 (64%) participants had community-acquired S aureus infections, and 132 (17%) had nosocomial S aureus infections. 47 (6%) had meticillin-resistant infections. 301 (40%) participants had an initial deep infection focus. Standard antibiotics were given for 29 (IQR 18-45) days; 619 (82%) participants received flucloxacillin. By week 12, 62 (17%) of participants who received rifampicin versus 71 (18%) who received placebo experienced treatment failure or disease recurrence, or died (absolute risk difference -1·4%, 95% CI -7·0 to 4·3; hazard ratio 0·96, 0·68-1·35, p=0·81). From randomisation to 12 weeks, no evidence of differences in serious (p=0·17) or grade 3-4 (p=0·36) adverse events were observed; however, 63 (17%) participants in the rifampicin group versus 39 (10%) in the placebo group had antibiotic or trial drug-modifying adverse events (p=0·004), and 24 (6%) versus six (2%) had drug interactions (p=0·0005).

INTERPRETATION

Adjunctive rifampicin provided no overall benefit over standard antibiotic therapy in adults with S aureus bacteraemia.

FUNDING

UK National Institute for Health Research Health Technology Assessment.

Management of bloodstream infections by infection specialists in France and Germany: a cross-sectional survey

INTRODUCTION

Bloodstream infections (BSI) are frequent infections worldwide. Our objective was to explore variation in the management of patients with BSI by infection specialists in France and Germany.

METHODS

This work is part of an international ESCMID cross-sectional internet-based questionnaire survey that was opened from December 2016 to February 2017. All hospital-based infection specialists, senior or trainees, giving at least weekly advice on positive blood cultures could participate. Their practices were evaluated using six clinical vignettes presenting an uncomplicated BSI due to different pathogens.

RESULTS

A hundred and ninety-six professionals (125 from Germany and 71 from France) participated. Systematic expert advice for positive blood cultures was more often available in Germany as compared with France (73 vs. 56%, p = 0.004). In Germany, the professional providing the expert advice was more often a microbiologist or a pharmacist as compared with France (p = 0.001 and p = 0.037, respectively) where it was more often an infectious diseases specialist. Fewer German respondents reported to advise systematic IV-oral switch of antibiotic therapy. German respondents also recommended less often combination therapy: for example for Enterococcus faecalis (64 vs. 43%, p = 0.015), ESBL E. coli (94 vs. 67%, p < 0.001) and Pseudomonas aeruginosa (76 vs. 37%, p < 0.001). Overall, management of candidaemia was more often compliant with the IDSA guidelines in France as compared with Germany, but no difference was noted for MRSA bacteraemia.

CONCLUSION

Our survey shows that wide variations exist between two neighboring countries in the recommendations by infection specialists for the management of BSI. International guidelines are needed.

The current role of glycopeptides in the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in not neutropenic adults: the viewpoint of a group of Italian experts

Staphylococcus aureus is still an important problem in clinical and therapeutic area, worldwide. In Italy, in recent years, methicillin resistance remained stable, yet considerably high, the percentage of strains of MRSA being around 40%. It was deemed interesting and timely to carry out a consensus conference using the RAND/UCLA method to collect the opinion of a group of experts in infectious diseases on the role of glycopeptides in the management of MRSA infections within several clinical scenarios and namely in pneumonia, bacteremia and endocarditis, joint replacement infections, skin and soft tissue infections, diabetic foot, abdominal infections and central nervous system infections. The scenarios proposed by the Scientific Committee have been validated by a group of experts in infectious diseases and then voted in three meetings of infectious disease specialists. The results obtained on each individual condition were analyzed and therapeutic recommendations on each of these were released.

Gram-Positive Bacterial Infections: Research Priorities, Accomplishments, and Future Directions of the Antibacterial Resistance Leadership Group

Antimicrobial resistance in gram-positive bacteria remains a challenge in infectious diseases. The mission of the Gram-Positive Committee of the Antibacterial Resistance Leadership Group (ARLG) is to advance knowledge in the prevention, management, and treatment of these challenging infections to improve patient outcomes. Our committee has prioritized projects involving methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE) due to the scope of the medical threat posed by these pathogens. Approved ARLG projects involving gram-positive pathogens include (1) a pharmacokinetics/pharmacodynamics study to evaluate the impact of vancomycin dosing on patient outcome in MRSA bloodstream infection (BSI); (2) defining, testing, and validating innovative assessments of patient outcomes for clinical trials of MRSA-BSI; (3) testing new strategies for "step-down" antibiotic therapy for MRSA-BSI; (4) management of staphylococcal BSIs in neonatal intensive care units; and (5) defining the impact of VRE bacteremia and daptomycin susceptibility on patient outcomes. This article outlines accomplishments, priorities, and challenges for research of infections caused by gram-positive organisms.

Evaluation and management of Staphylococcus aureus bacteriuria: an updated review

BACKGROUND AND AIMS

There is little guidance regarding the evaluation and management of patients with Staphylococcus aureus bacteriuria (SABU). Here, we aimed to provide an up-to-date review of the literature.

METHODS

We searched PubMed, Scopus, and clinical trial registries for articles evaluating the epidemiology of SABU, risk factors of SABU, the association of SABU with urinary tract infection, bacteremia and invasive S. aureus infections, and the management of patients with SABU.

RESULTS

S. aureus is an uncommon isolate in urine cultures. It is more common among certain patients, e.g., patients with indwelling urinary tract devices or prior urinary tract instrumentation. SABU may represent asymptomatic bacteriuria, primary urinary tract infection, or hematogenous seeding of the urinary tract associated with other foci of infection. SABU may also serve as the focus for subsequent bacteremia and invasive infections. We did not find any clinical trials regarding the management of patients with SABU.

CONCLUSIONS

Based on our review, we suggest an algorithmic approach for the evaluation and management of patients with SABU. However, evidence from clinical trials is lacking and there are several gaps in the current literature. These are discussed in this review.

Staphylococcus aureus bacteraemia and endocarditis - epidemiology and outcome: a review

PURPOSE

To review the epidemiology of Staphylococcus aureus bacteraemia (SAB) and endocarditis (SAE), and discuss the short- and long-term outcome.  Materials and methods: A literature review of the epidemiology of SAB and SAE.

RESULTS

The reported incidence of SAB in Western countries is 16-41/100,000 person-years. Increasing incidence has been observed in many regions, in Iceland by 27% during 1995-2008. The increase is believed to depend on changes in population risk factors and possibly better and more frequent utilization of diagnostic procedures. S. aureus is now the leading causes of infective endocarditis (IE) in many regions of the world. It accounts for 15-40% of all IE cases, and the majority of cases in people who inject drugs (PWID). Recently, the incidence of SAE in PWID in Stockholm, Sweden, was found to be 2.5/1000 person-years, with an in-hospital mortality of 2.5% in PWID as compared to 15% in non-drug users. The 30-day mortality associated with SAB amounts to 15-25% among adults in Western countries, but is lower in children (0-9%). Mortality associated with SAE is high (generally 20-30% in-hospital mortality), and symptomatic cerebral embolizations are common (12-35%). The 1-year mortality reported after SAB and SAE is 19-62% and reflects deaths from underlying diseases and complications caused by the infection. In a subset of SAE cases, valvular heart surgery is needed (15-45%), but active intravenous drug use seems to be a reason to refrain from surgery. Despite its importance, there are insufficient data on the optimal management of SAB and SAE, especially on the required duration of antibiotic therapy.  Conclusions: The epidemiology of SAB and SAE has been changing in the past decades. They still carry a substantial morbidity and mortality. Intensified studies on treatment are warranted for improving patient outcome.

Risk assessment for infected endocarditis in Staphylococcus aureus bacteremia patients: When is transesophageal echocardiography needed?

Aims:

Echocardiography is the main technique for the diagnosis of endocarditis in patients with Staphylococcus aureus bacteremia (SAB), but a consensus about performing transthoracic echocardiography or transesophageal echocardiography (TEE) as first-line tests is currently lacking. Recently, a new scoring system has been proposed by Palraj et al. to guide the use of TEE in this population. Our aim was to validate this scoring system or modify it, if necessary.

Methods and results:

Data from SAB patients admitted from 2012 to 2014 were collected. We tested the Palraj scores to stratify patients’ risk for endocarditis. Moreover, we analyzed our population to identify any other possible clinical predictors of endocarditis not included in the score. Endocarditis was diagnosed in 38 of 205 patients (18.5%). Palraj’s score was effective in the detection of patients at high risk of endocarditis. In addition, we identified the presence of cardiac devices, prolonged bacteremia and intravenous drug abuse (IVDA) as elements strongly correlated with endocarditis. Two scoring systems (Day-1 and Day-5) were derived including IVDA as a variable. Using a Day-1 cut-off value ≥5 and a Day-5 cut-off value ≥2, the ‘modified Palraj’s score’ showed sensitivities of 42.1% and 97.0% and specificities of 88.6% and 32.0% for Day-1 and Day-5 scores, respectively.

Conclusion:

We modify and expand upon an effective scoring system to identify SAB patients at high risk for endocarditis in order to guide use of TEE. The inclusion of IVDA in the criteria for the calculation of the scores improves its effectiveness.

Impact of a pharmacist-driven care package on Staphylococcus aureus bacteremia management in a large community healthcare network: A propensity score-matched, quasi-experimental study

OBJECTIVES

Staphylococcus aureus bacteremia (SAB) is an important cause of morbidity and mortality. Suboptimal treatment has been associated with poor patient outcomes. Our antimicrobial stewardship program (ASP) evaluated SAB management based on predefined performance measures both prior to and after instituting a "care package" intervention led by clinical pharmacists and infectious diseases physicians. The primary outcome included a 4-point "optimal care score" (OCS) consisting of targeted antibiotic therapy within 24hours, repeating blood cultures, antibiotic duration assessment, and appropriate duration of therapy. The presence of an ID consult, SAB readmission and mortality were also assessed.

METHODS

This was a quasi-experimental, propensity score matched study of SAB management. Adult patients were retrospectively evaluated from October 2011 - October 2012, and intervention took place from November 2013 - December 2015. Intervention consisted of a clinical pharmacist contacting the primary team after identification of SAB to recommend (1) appropriate antibiotics within 24hours, (2) repeat blood cultures to document clearance, (3) assessment for metastatic infection, (4) and appropriate duration of therapy. These constituted the 4-point OCS. ID consult was also recommended. Patients were propensity score matched 1:2 based on age, diabetes, presence of hardware, methicillin-resistant S. aureus (MRSA) isolate, and stratified infectious source. Patients ≥18 with SAB were included.

RESULTS

Intervention was associated with improved adherence to each metric within the OCS, and more patients in the intervention cohort achieved a perfect OCS of 4. Intervention was associated with a lower rate of readmission and mortality.

CONCLUSION

A pharmacist-driven, ASP intervention on SAB therapy was associated with increased adherence to core SAB care metrics and reduced relapse and mortality.

Association of Evidence-Based Care Processes With Mortality in Staphylococcus aureus Bacteremia at Veterans Health Administration Hospitals, 2003-2014

IMPORTANCE

Staphylococcus aureus bacteremia is common and frequently associated with poor outcomes. Evidence indicates that specific care processes are associated with improved outcomes for patients with S aureus bacteremia, including appropriate antibiotic prescribing, use of echocardiography to identify endocarditis, and consultation with infectious diseases (ID) specialists. Whether use of these care processes has increased in routine care for S aureus bacteremia or whether use of these processes has led to large-scale improvements in survival is unknown.

OBJECTIVE

To examine the association of evidence-based care processes in routine care for S aureus bacteremia with mortality.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective observational cohort study examined all patients admitted to Veterans Health Administration (VHA) acute care hospitals who had a first episode of S aureus bacteremia from January 1, 2003, through December 31, 2014.

EXPOSURES

Use of appropriate antibiotic therapy, echocardiography, and ID consultation.

MAIN OUTCOMES AND MEASURES

Thirty-day all-cause mortality.

RESULTS

Analyses included 36 868 patients in 124 hospitals (mean [SD] age, 66.4 [12.5] years; 36 036 [97.7%] male), including 19 325 (52.4%) with infection due to methicillin-resistant S aureus and 17 543 (47.6%) with infection due to methicillin-susceptible S aureus. Risk-adjusted mortality decreased from 23.5% (95% CI, 23.3%-23.8%) in 2003 to 18.2% (95% CI, 17.9%-18.5%) in 2014. Rates of appropriate antibiotic prescribing increased from 2467 (66.4%) to 1991 (78.9%), echocardiography from 1256 (33.8%) to 1837 (72.8%), and ID consultation from 1390 (37.4%) to 1717 (68.0%). After adjustment for patient characteristics, cohort year, and other care processes, receipt of care processes was associated with lower mortality, with adjusted odds ratios of 0.74 (95% CI, 0.68-0.79) for appropriate antibiotics, 0.73 (95% CI, 0.68-0.78) for echocardiography, and 0.61 (95% CI, 0.56-0.65) for ID consultation. Mortality decreased progressively as the number of care processes that a patient received increased (adjusted odds ratio for all 3 processes compared with none, 0.33; 95% CI, 0.30-0.36). An estimated 57.3% (95% CI, 48.4%-69.9%) of the decrease in mortality between 2003 and 2014 could be attributed to increased use of these evidence-based care processes.

CONCLUSIONS AND RELEVANCE

Mortality associated with S aureus bacteremia decreased significantly in VHA hospitals, and a substantial portion of the decreasing mortality may have been attributable to increased use of evidence-based care processes. The experience in VHA hospitals demonstrates that increasing application of these care processes may improve survival among patients with S aureus bacteremia in routine health care settings.

Once-Daily Treatments for Methicillin-Susceptible Staphylococcus aureus Bacteremia: Are They Good Enough?

PURPOSE OF THE REVIEW

Methicillin-sensitive Staphylococcus aureus (MSSA) bacteremia is a common cause of morbidity and mortality. First-line treatment requires frequent daily doses of an anti-staphylococcal beta-lactam. However, some physicians prescribe simpler once-daily regimens to improve compliance and improve healthcare utilization. We reviewed the literature regarding advantages, pitfalls, and efficacy of once-daily treatment options for MSSA bacteremia.

RECENT FINDINGS

Several once-daily antibiotics are effective in vitro against MSSA (ceftriaxone, daptomycin, telavancin, dalbavancin, oritavancin, tedizolid, ertapenem, fluoroquinolones, and others), but there is insufficient evidence to support these agents for MSSA bacteremia. Ceftriaxone may be considered for therapy completion with MSSA bacteremia from osteomyelitis, and daptomycin may be considered in patients who cannot tolerate first-line therapy. However, they have not been compared to traditional second-line agents, and their role remains uncertain. Current evidence does not support the use of once-daily treatment options for MSSA bacteremia.

["Choosing wisely" in infectious diseases : Overuse of antibiotics - too few vaccinations]

The "choosing wisely" recommendations of the German Society of Internal Medicine (DGIM) and its specialist societies address diagnostic and therapeutic procedures, which are of particular medical importance but applied too often or too rarely in clinical practice. The aim is to further improve treatment of patients. Important topics of overuse and insufficient treatment related to the diagnostics, therapy, prevention and exclusion of infectious diseases could be identified. These topics not only play an important role in the discipline of infectious diseases but are also relevant for other internal medical disciplines. These topics related to infectious diseases have also been integrated into the recommendations of the German Society of Gastroenterology, Digestive and Metabolic Diseases as well as the German Societies for Internal Intensive Care and Emergency Medicine, for Pneumology, for Nephrology and for Rheumatology. The pivotal issues of the recommendations are the inappropriate use of antibiotics and insufficient vaccination rates.

Integration of DPC and clinical microbiological data in Japan reveals importance of confirming a negative follow-up blood culture in patients with MRSA bacteremia

Methicillin-resistant Staphylococcus aureus (MRSA) bacteremia is one of the commonest and most life-threatening of all infectious diseases. The morbidity and mortality rates associated with MRSA bacteremia are higher than those associated with bacteremia caused by other pathogens. A common guideline in MRSA bacteremia treatment is to confirm bacteremia clearance through additional blood cultures 2-4 days after initial positive cultures and as needed thereafter. However, no study has presented statistical evidence of how and to what extent confirming a negative follow-up blood culture impacts clinical outcome. We present this evidence for the first time, by combining clinical microbiological data of blood cultures and the DPC administrative claims database; both had been systematically accumulated through routine medical care in hospitals. We used electronic medical records to investigate the clinical background and infection source in detail. By analyzing data from a university hospital, we revealed how survival curves change when a negative follow-up blood culture is confirmed. We also demonstrated confirmation of a negative culture is significantly associated with clinical outcomes: there was a more than three-fold increase in mortality risk (after adjusting for clinical background) if a negative blood culture was not confirmed within 14 days of the initial positive blood culture. Although we used data from only one university hospital, our novel approach and results will be a basis for future studies in several hospitals in Japan to provide statistical evidence of the clinical importance of confirming a negative follow-up blood culture in bacteremia patients, including those with MRSA infections.

Incidence, prevalence, and management of MRSA bacteremia across patient populations-a review of recent developments in MRSA management and treatment

Methicillin-resistant Staphylococcus aureus (MRSA) infection is still a major global healthcare problem. Of concern is S. aureus bacteremia, which exhibits high rates of morbidity and mortality and can cause metastatic or complicated infections such as infective endocarditis or sepsis. MRSA is responsible for most global S. aureus bacteremia cases, and compared with methicillin-sensitive S. aureus, MRSA infection is associated with poorer clinical outcomes. S. aureus virulence is affected by the unique combination of toxin and immune-modulatory gene products, which may differ by geographic location and healthcare- or community-associated acquisition. Management of S. aureus bacteremia involves timely identification of the infecting strain and source of infection, proper choice of antibiotic treatment, and robust prevention strategies. Resistance and nonsusceptibility to first-line antimicrobials combined with a lack of equally effective alternatives complicates MRSA bacteremia treatment. This review describes trends in epidemiology and factors that influence the incidence of MRSA bacteremia. Current and developing diagnostic tools, treatments, and prevention strategies are also discussed.

Telavancin in the Treatment of Concurrent Staphylococcus aureus Bacteremia: A Retrospective Analysis of ATLAS and ATTAIN Studies

Introduction

Concurrent Staphylococcus aureus bacteremia (SAB) worsens outcomes and increases mortality in patients with complicated skin and skin structure infections (cSSSI), hospital-acquired bacterial pneumonia, and ventilator-associated bacterial pneumonia (HABP/VABP). These challenges highlight the need for alternative treatments. Telavancin (TLV), a bactericidal lipoglycopeptide with high in vitro potency, effectively treats patients with cSSSI and HABP/VABP caused by Gram-positive pathogens, particularly S. aureus.

Methods

This retrospective analysis evaluated patients from the Assessment of Telavancin in Complicated Skin and Skin Structure Infections and Assessment of Telavancin for Treatment of Hospital-Acquired Pneumonia studies with baseline, concurrent SAB. Differences in the clinical cure rates at test-of-cure and safety outcomes were compared for TLV vs vancomycin (VAN) treatment groups.

Results

A total of 105 patients, 32 cSSSI and 73 HABP/VABP, had baseline, concurrent SAB. The clinical cure rates for all-treated SAB patients in the cSSSI (TLV 57.1% and VAN 54.5%) and HABP/VABP (TLV 54.3% and VAN 47.2%) groups were comparable. For both types of infections, the safety profile of TLV and VAN showed similar incidences of adverse events (AEs), serious AEs, or AEs leading to discontinuation. One VAN-treated patient died in the cSSSI group, and there were 13 deaths in each treatment arm of the HABP/VABP group.

Conclusion

This retrospective analysis demonstrated that TLV is clinically comparable in both efficacy and safety to VAN, and, therefore, may be an appropriate therapeutic option for the treatment of patients with HABP/VABP or cSSSI and concurrent SAB. Given the limited sample size in this subgroup, the interpretation of these results is limited.

Funding

Theravance Biopharma Antibiotics, Inc.

Empiric antibiotic protocols for cancer patients with neutropenia: a single-center study of treatment efficacy and mortality in patients with bacteremia

BACKGROUND

There are several empiric antibiotic treatment options for febrile neutropenia, yet there is no universally-accepted initial protocol. We aimed to assess the performance of a protocol (piperacillin, gentamicin and cefazolin) introduced over 40 years ago and compare its coverage against bacteria isolated from blood of neutropenic patients with that of various commonly used antibiotic treatment protocols.

METHODS

Adults with neutropenia admitted between 2003 and 2012 to the hemato-oncologic departments and in whom blood cultures were taken on admission were included. Appropriateness of several common antibiotic protocols was assessed based on the susceptibility of the blood isolates. Crude mortality rates were computed by the susceptibility of bacteria isolated from patients' blood to the actual treatment given.

RESULTS

In total, 180 admissions of neutropenic patients (95 in patients who had fever above 38 °C) with positive blood cultures were analyzed. The actual antibiotic regimen prescribed was deemed appropriate in 82% of bacteremia episodes. The recommended institutional protocol was used in 62% of bacteremia episodes in neutropenic patients. This protocol would have been appropriate in 85% of all neutropenic bacteremia episodes and 89% of episodes in febrile neutropenia patients compared with piperacillin/tazobactam (79%, P = 0.13 and 76%, P = 0.002, respectively) and imipenem (93%, P = 0.004 and 92%, P = 0.74, respectively). Isolation of bacteria resistant to the actual antibiotic treatment given was associated with higher mortality at one week and at 30 days.

CONCLUSION

Common current antibiotic regimens provide similar coverage among febrile neutropenic patients, whereas broad spectrum antibiotic combinations maximize coverage among neutropenic patients.

The Risk of Cardiac Device-Related Infection in Bacteremic Patients Is Species Specific: Results of a 12-Year Prospective Cohort

BACKGROUND

The species-specific risk of cardiac device-related infection (CDRI) among bacteremic patients is incompletely understood.

METHODS

We conducted a prospective cohort study of hospitalized patients from October 2002 to December 2014 with a cardiac device (CD) and either Staphylococcus aureus bacteremia (SAB) or Gram-negative bacteremia (GNB). Cardiac devices were defined as either prosthetic heart valves (PHVs), including valvular support rings, permanent pacemakers (PPMs)/automatic implantable cardioverter defibrillators (AICDs), or left ventricular assist devices (LVADs).

RESULTS

During the study period, a total of 284 patients with ≥1 CD developed either SAB (n = 152 patients) or GNB (n = 132 patients). Among the 284 patients, 150 (52.8%) had PPMs/AICDs, 72 (25.4%) had PHVs, 4 (1.4%) had LVADs, and 58 (20.4%) had >1 device present. Overall, 54.6% of patients with SAB and 16.7% of patients with GNB met criteria for definite CDRI (P < .0001). Multivariable logistic regression analysis revealed that 3 bacterial species were associated with an increased risk for CDRI: Staphylococcus aureus (odds ratio [OR] = 5.57; 95% confidence interval [CI], 2.16-14.36), Pseudomonas aeruginosa (OR = 50.28; 95% CI, 4.16-606.93), and Serratia marcescens (OR = 7.75; 95% CI, 1.48-40.48).

CONCLUSIONS

Risk of CDRI among patients with bacteremia varies by species. Cardiac device-related infection risk is highest in patients with bacteremia due to S aureus, P aeruginosa, or S marcescens. By contrast, it is lower in patients with bacteremia due to other species of Gram-negative bacilli. Patients with a CD who develop bacteremia due to either P aeruginosa or S marcescens should be considered for diagnostic imaging to evaluate for the presence of CDRI.

Correcting a Fundamental Flaw in the Paradigm for Antimicrobial Susceptibility Testing

The emergence and prevalence of antibiotic-resistant bacteria are an increasing cause of death worldwide, resulting in a global ‘call to action’ to avoid receding into an era lacking effective antibiotics. Despite the urgency, the healthcare industry still relies on a single in vitro bioassay to determine antibiotic efficacy. This assay fails to incorporate environmental factors normally present during host-pathogen interactions in vivo that significantly impact antibiotic efficacy. Here we report that standard antimicrobial susceptibility testing (AST) failed to detect antibiotics that are in fact effective in vivo; and frequently identified antibiotics that were instead ineffective as further confirmed in mouse models of infection and sepsis. Notably, AST performed in media mimicking host environments succeeded in identifying specific antibiotics that were effective in bacterial clearance and host survival, even though these same antibiotics failed in results using standard test media. Similarly, our revised media further identified antibiotics that were ineffective in vivo despite passing the AST standard for clinical use. Supplementation of AST medium with sodium bicarbonate, an abundant in vivo molecule that stimulates global changes in bacterial structure and gene expression, was found to be an important factor improving the predictive value of AST in the assignment of appropriate therapy. These findings have the potential to improve the means by which antibiotics are developed, tested, and prescribed.

•

Standard antimicrobial susceptibility testing (AST) is fundamentally flawed because it is based largely on in vitro efficacy.

•

AST performed under conditions that mimic natural infections improves the assignment of appropriate antibiotic therapy.

•

In vivo altered susceptibility (IVAS) provides a new paradigm for drug discovery and therapeutic intervention.

Drug testing often excludes potent antibiotics for the treatment of bacterial infections, while frequently identifying antibiotics that are ineffective. However, drug testing under conditions that mimic natural infections succeeded in identifying effective antibiotics, even though these same antibiotics failed standard tests. This work suggests that standard drug-testing may be hindering patient treatment and slowing the process of discovery of new, effective, and safe antibiotics because it disqualifies effective compounds. These findings call for an overhaul of standardized drug testing which hasn't changed in > 50 years.

Impact of prompt intervention in response to positive blood culture results during weekends by collaboration between infectious disease specialists and microbiology laboratory staff

The purpose of this investigation was to elucidate the impact of prompt intervention for patients whose blood culture results became positive during weekends, as this is not standard care in some countries. A retrospective cohort study was conducted in a tertiary referral hospital. From June 2015, results of positive blood cultures became available during weekends. If infectious disease specialists identified cases of bacteremia on suboptimal antimicrobial coverage, they contacted the primary team for modification of antibiotic treatment. We reviewed patients whose blood culture results became positive during weekends, comparing the pre-intervention (September 2014 to May 2015) and post-intervention (June 2015 to February 2016) periods. In total, 1081 (post-intervention 568 [52.5%]) bacteremia episodes were included (median patient age [interquartile range, IQR]: 72 [60-82] years; men: 625 [57.8%]). During the post-intervention period, 187 (32.9%) bacteremia episodes were detected during weekends. Infectious disease specialists evaluated the positive blood culture results 1, 2, and ≥3 days prior in 77 (13.6%), 88 (15.5%), and 22 (3.9%) cases, respectively. Although the 7- and 30-day mortality did not significantly improve after the intervention, the length of hospital stay (LOS) in the hospital-acquired bacteremia group was significantly reduced during the post-intervention period after controlling for confounders (post- vs. pre-intervention: median days [IQR]: 37 [19-63] vs. 46.5 [24.8-86.3], p = 0.030). Blood culture results became positive during weekends in one-third of bacteremia cases. The LOS was shortened after the intervention in the hospital-acquired bacteremia group. This could be an important antimicrobial stewardship target.

Optimal duration of antimicrobial therapy for uncomplicated Gram-negative bloodstream infections

PURPOSE

Optimal antimicrobial treatment duration for Gram-negative bloodstream infection (BSI) remains unclear. This retrospective cohort study examined effectiveness of short (7-10 days) and long (>10 days) courses of antimicrobial therapy for uncomplicated Gram-negative BSI.

METHODS

Hospitalized adults with uncomplicated Gram-negative BSI at Palmetto Health hospitals in Columbia SC, USA from January 1, 2010 to December 31, 2013 were identified. Multivariate Cox proportional hazards regression with propensity score adjustment was used to examine risk of treatment failure in the two groups.

RESULTS

During the study period, 117 and 294 patients received short and long courses of antimicrobial therapy for uncomplicated Gram-negative BSI, respectively. Overall, the median age was 67 years, 258 (63%) were women, 282 (69%) had urinary source of infection, and 271 (66%) had BSI due to Escherichia coli. The median duration of antimicrobial therapy was 8.5 and 13.3 days in the short and long treatment groups, respectively. After adjustment for the propensity to use a short course of therapy, risk of treatment failure was higher in patients receiving short compared to long courses of antimicrobial agents (HR 2.60, 95% CI: 1.20-5.53, p = 0.02). Other risk factors for treatment failure included liver cirrhosis (HR 5.83, 95% CI: 1.89-15.02, p = 0.004) and immune compromised status (HR 4.30, 95% CI: 1.57-10.80, p = 0.006). Definitive antimicrobial therapy with intravenous or highly bioavailable oral agents was associated with reduced risk of treatment failure (HR 0.33, 95% CI: 0.14-0.73, p = 0.006).

CONCLUSIONS

The current results support common clinical practice of 2 weeks of antimicrobial therapy for uncomplicated Gram-negative BSI.

Clinical predictors and clinical prediction rules to estimate initial patient risk for infective endocarditis in Staphylococcus aureus bacteraemia: a systematic review and meta-analysis

OBJECTIVES

We conducted a meta-analysis to summarize diagnostic properties of risk factors and clinical prediction rules for diagnosing infective endocarditis (IE) in Staphylococcus aureus bacteraemia (SAB).

METHODS

We searched MEDLINE, Embase, and the Cochrane Database from inception to 6 January 2016 to identify studies evaluating risk factors and clinical prediction rules for IE in SAB patients. Pooled estimates of diagnostic properties for main risk factors were calculated using a bivariate random effects model.

RESULTS

Of 962 articles identified, 30 studies were included. These involved 16 538 SAB patients including 1572 IE cases. Risk factors with positive likelihood ratio (PLR) greater than 5 included embolic events (PLR 12.7, 95% CI 9.2-17.7), pacemakers (PLR 9.7, 95% CI 3.7-21.2), history of previous IE (PLR 8.2, 95% CI 3.1-22.0), prosthetic valves (PLR 5.7, 95% CI 3.2-9.5), and intravenous drug use (PLR 5.2, 95% CI 3.8-6.9). The only clinical factor with negative likelihood ratio (NLR) less than 0.5 was documented clearance of bacteraemia within 72 hours (NLR range 0.32-0.35). Of the nine published clinical prediction rules for ruling out IE, five had an NLR below 0.1.

CONCLUSIONS

SAB patients with high-risk features (embolic events, pacemakers, prosthetic valves, previous IE, or intravenous drug use) should undergo a trans-esophageal echocardiography (TEE) for IE. Clinical prediction rules show promise in safely ruling out endocarditis, but require validation in future studies.

[Antibiotic stewardship and Staphylococcus aureus Bacteremia]

Rates of antibiotic resistance are increasing worldwide and impact on the treatment of patients with bacterial infections. A broad and uncritical application in inpatient and outpatient settings as well as in agriculture has been recognized as the main driving force. Antibiotic stewardship (ABS) programs aim at countering this worrisome development using various direct interventions such as infectious disease counseling. Blood stream infections caused by Staphylococcus (S.) aureus are severe infections associated with high mortality rates. ABS interventions such as de-eskalation of the antibiotic regimen or application of narrow-spectrum beta-lactam antibiotics can significantly reduce mortality rates. In this review, we discuss the importance of ABS programs and infectious disease counseling for the treatment of S. aureus blood stream infection.

Clinical presentation, management and outcomes of Staph aureus bacteremia (SAB) in older adults

AIM

The incidence of Staphylococcus aureus bacteremia (SAB) increases with advancing age with higher mortality reported in older adults. We aimed to describe the clinical presentation, management and outcomes of older patients with SAB.

METHODS

We analyzed data from a retrospectively collected database including 1692 patients with SAB, and compared 1158 older patients (≥65 years) with 534 younger patients (<65 years) in terms of clinical features, management of infection, and outcomes.

RESULTS

Older patients were significantly less likely to be febrile on presentation, with 37.5 % (415/1106) of older patients presenting with normal body temperature [versus 29.2 % (152/520) of younger patients]. Older patients were however, more likely to have leukocytosis, septic shock, lower heart rate and lower diastolic blood pressure compared with younger patients. Management of older patients included significantly less imaging studies, performance of transesophageal echocardiogram (TEE) and infectious diseases consultation. TEE was performed less in older patients [124/726 (17.1 %) versus 72/285 (25.3 %)]. Mortality was significantly higher in older patients [550/1158 (47.5 %) versus 124/534 (23.2 %)], with predictors for mortality for the entire cohort in multivariate analysis including older age, higher Charlson comorbidity index, female sex, impaired functional capacity, pneumonia or primary bacteremia, and non-performance of TEE.

CONCLUSIONS

Mortality rates in older patients with SAB are higher compared with younger patients. Several diagnostic and therapeutic procedures in the management of SAB were less likely to be performed in older patients in our cohort. These may have implications on outcome and should not be dismissed on the basis of age alone.

Ceftaroline fosamil monotherapy for methicillin-resistant Staphylococcus aureus bacteremia: a comparative clinical outcomes study

OBJECTIVES

Vancomycin is the treatment of choice for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia; however, its use has been subject to scrutiny due to failure in severe infections. Ceftaroline fosamil (CPT-F) is approved for MRSA acute bacterial skin and skin structure infections, but not for bloodstream infections. The clinical outcomes of treatment with CPT-F in patients with MRSA bacteremia were evaluated.

METHODS

Patients diagnosed with MRSA bacteremia at Henry Ford Hospital in Detroit, Michigan, USA, involving isolates with a vancomycin minimum inhibitory concentration ≥1.0mg/l and susceptible in vitro to CPT-F, were systematically reviewed retrospectively. Ceftaroline fosamil-treated patients were matched with at least two vancomycin- and/or one daptomycin-treated control patient based on age-patients age 65 years or greater or less than 65 years of age. Outcomes evaluated included the duration of hospitalization, duration of therapy, adverse events, relapse, hospital readmission, and death.

RESULTS

Thirty consecutive cases of MRSA bacteremia treated with CPT-F during the period May 2011 to June 2013 were identified; these patients were matched to 56 MRSA bacteremia patients treated with vancomycin and 46 MRSA bacteremia patients treated with daptomycin. The primary source of MRSA bacteremia in the cohort treated with CPT-F was endocarditis (n=7, 23%), skin/wound (n=9, 30%), and bone/joint (n=8, 27%). The MRSA bacteremia in those treated with CPT-F was community-acquired in 43% of cases, healthcare-associated in 43%, and hospital-acquired in 13%. The mean length of hospital stay for these patients was 22 days. The overall 30-day mortality rate was 13% (n=4) in CPT-F patients versus 24% (n=11) in daptomycin patients and 11% (n=6) in vancomycin patients (p=0.188).

CONCLUSIONS

CPT-F demonstrated comparable clinical outcomes in MRSA bacteremia patients compared with the other agents, especially as salvage therapy.