Episodes Of Staphylococcus Aureus Bacteremia Research Articles

Clinical Outcomes of Oral Antibiotic Switch in Children with Staphylococcus aureus Bacteremia.

Staphylococcus aureus is one of the leading causes of bacteremia in children. In this study, we aimed to evaluate our center's experience on the etiology, management, and outcomes of pediatric Staphylococcus aureus bacteremia (SAB) with particular focus on transitioning to oral antibiotic therapy. This retrospective cohort study included children aged ≤ 19 years diagnosed with SAB over a 5-year period. The main outcome was poor clinical outcome related to SAB defined as (1) recurrence of SAB within 30 days after discontinuation of SAB treatment and (2) any-cause mortality within 30 days after detection of SAB. Over a 5-year period, 88 SAB episodes of 76 unique patients were included. The most common source of SAB attributed to central line (n = 34), followed by osteoarticular (n = 24), infections. All patients received at least one day of intravenous (IV) antibiotics and treatment was switched to an oral agent in 45.5% of SAB episodes. Sources of SAB in the oral switch group were osteoarticular (n = 21), skin and soft tissue (n = 7), central line (n = 3), thrombophlebitis (n = 2), head and neck infection (n = 1), and unknown (n = 6). 30-day mortality and SAB recurrence within 30 days after initial treatment completion occurred in 3 and 5 SAB episodes, respectively. None of the patients in oral switch group had poor clinical outcomes. Our study results indicate that 30-day any-cause mortality and SAB-related mortality is low in children. Similar to growing adult literature, oral switch in SAB treatment was not associated with poor SAB outcomes in selected patients.

Impact of a Bundle of Interventions on Quality-of-Care Indicators for Staphylococcus aureus Bacteraemia: A Single-Centre, Quasi-Experimental, Before-After Study.

Staphylococcus aureus bacteraemia (SAB) is a life-threatening bloodstream infection. Improved adherence to quality-of-care indicators (QCIs) can significantly enhance patient outcomes. This quasi-experimental study evaluated the impact of a bundle of interventions on QCI adherence in adult patients with SAB. Additionally, a molecular rapid diagnostic test (mRDT) for S. aureus and methicillin resistance was introduced during weekdays. We compared pre-intervention (January-December 2022) and post-intervention (May 2023-April 2024) data on QCI adherence and time to appropriate treatment. A total of 56 and 40 SAB episodes were included in the pre- and post-intervention periods, respectively. Full QCI adherence significantly increased from 28.6% to 67.5% in the post-intervention period (p < 0.001). The mRDT diagnosed SAB in eight cases (26.6%), but the time to achieve appropriate target therapy did not improve in the post-intervention period (54 h (IQR 30-74) vs. 72 h (IQR 51-83), p = 0.131). The thirty-day mortality rate was comparable between the two periods (17.9% vs. 12.5%, p = 0.476). This study demonstrates that a bundle of interventions can substantially improve adherence to SAB management QCIs.

Australian Group on Antimicrobial Resistance (AGAR) Australian Staphylococcus aureus Surveillance Outcome Program (ASSOP) Bloodstream Infection Annual Report 2022.

From 1 January to 31 December 2022, fifty-five institutions across Australia participated in the Australian Staphylococcus aureus Surveillance Outcome Program (ASSOP). The aim of ASSOP 2022 was to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that were antimicrobial resistant, with particular emphasis on susceptibility to methicillin and on characterisation of the molecular epidemiology of the methicillin-resistant isolates. A total of 3,214 SAB episodes were reported, of which 77.5% were community-onset. Overall, 15.0% of S. aureus were methicillin resistant. The 30-day all-cause mortality associated with methicillin-resistant SAB was 21.4%, which was significantly different to the 16.8% all-cause mortality associated with methicillin-susceptible SAB (p = 0.02). With the exception of the β-lactams and erythromycin, antimicrobial resistance in methicillin-susceptible S. aureus was rare. However, in addition to the β-lactams, approximately 31% of methicillin-resistant S. aureus (MRSA) were resistant to ciprofloxacin; 30% to erythromycin; 13% to tetracycline; 11% to gentamicin; and 2% to co-trimoxazole. One MRSA isolate, with a daptomycin MIC of 1.5 mg/L, harboured the A302V mprF and A23V cls2 mutations. When applying the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, teicoplanin resistance was detected in one MRSA isolate. Resistance to vancomycin or linezolid was not detected. Resistance to non-β-lactam antimicrobials was largely attributable to the healthcare-associated MRSA (HA-MRSA) clone ST22-IV [2B] (EMRSA-15), and to the community-associated MRSA (CA-MRSA) clone ST45-V [5C2&5] which has acquired resistance to multiple antimicrobials including ciprofloxacin, clindamycin, erythromycin, gentamicin, and tetracycline. The ST22-IV [2B] (EMRSA-15) clone is the predominant HA-MRSA clone in Australia. Nonetheless, 86% of methicillin-resistant SAB episodes were due to CA-MRSA clones. Although polyclonal, approximately 72% of CA-MRSA clones were characterised as ST93-IV [2B] (Queensland clone); ST5-IV [2B]; ST45-V [5C2&5]; ST1-IV [2B]; ST30-IV [2B]; ST97-IV [2B]; ST953-IV [2B]; and ST8-IV [2B]. As CA-MRSA is well established in the Australian community, it is important to monitor antimicrobial resistance patterns in community- and healthcare-associated SAB as this information will guide therapeutic practices in treating S. aureus bacteraemia.

Predictors of infectious foci on FDG PET/CT in Staphylococcus aureus bacteremia

We looked for predicting factors for the detection of infectious foci on 18F-fluorodeoxyglucose-positron emission tomography in combination with computed tomography (FDG PET/CT) among patients with Staphylococcus aureus bacteremia (SAB) who participated in an interventional study that was conducted at Rambam Health Care Campus, between July 1, 2015 and February 1, 2019. The primary outcome was an infectious focus detected by FDG PET/CT. Independent predictors for detection of focal infection were identified using univariate followed by a logistic regression multivariate analysis. We included 149 patients with 151 separate episodes of SAB who underwent FDG-PET/CT. Focal infections were detected in 107 patients (70.8%). Independent predictors for focal infection detection were community acquisition of bacteremia with odds ratio (OR) 3.03 [95% confidence interval (CI) 1.04–8.77], p-0.042 and C reactive protein (CRP) with OR 1.09 [95% CI 1.04–1.14], p < 0.001. Primary bacteremia was inversely associated with focal infection detection with OR 0.27 [0.10–0.69], p = 0.007, as were the pre-scan blood glucose levels OR 0.9 [0.98–0.99], p-0.004. The latter stayed significant in the subgroup of patients with diabetes mellitus. To conclude, patients with community-acquired bacteremia or high CRP levels should be carefully investigated for focal infection. Patients who present with primary bacteremia seem to be at low risk for focal infection.

Australian Group on Antimicrobial Resistance (AGAR) Australian Staphylococcus aureus Surveillance Outcome Program (ASSOP).

From 1 January to 31 December 2021, forty-eight institutions around Australia participated in the Australian Staphylococcus aureus Surveillance Outcome Programme (ASSOP). The aim of ASSOP 2021 was to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that were antimicrobial resistant, with particular emphasis on susceptibility to methicillin and on characterisation of the molecular epidemiology of the methicillin-resistant isolates. A total of 2,928 SAB episodes were reported, of which 78.4% were community-onset. Overall, 16.9% of S. aureus isolates were methicillin resistant. The 30-day all-cause mortality associated with methicillin-resistant SAB was 15.0%, which was not significantly different from the 14.4% all-cause mortality associated with methicillin-susceptible SAB (p = 0.7). With the exception of the β-lactams and erythromycin, antimicrobial resistance in methicillin-susceptible S. aureus was rare. However, in addition to the β-lactams, approximately 36% of methicillin-resistant S. aureus (MRSA) were resistant to ciprofloxacin; 30% to erythromycin; 15% to tetracycline; 16% to gentamicin; and 3% to co-trimoxazole. When applying the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, teicoplanin resistance was detected in three S. aureus isolates. Resistance to vancomycin or linezolid was not detected. Resistance to non-β-lactam antimicrobials was largely attributable to the healthcare-associated MRSA (HA-MRSA) clone ST22-IV [2B] (EMRSA-15), and the community-associated MRSA (CA-MRSA) clone ST45-V [5C2&5] which has acquired multiple antimicrobial resistance determinants including ciprofloxacin, erythromycin, clindamycin, gentamicin and tetracycline. The ST22-IV [2B] (EMRSA-15) clone is the predominant HA-MRSA clone in Australia. Nonetheless, 85% of methicillin-resistant SAB episodes were due to CA-MRSA clones. Although polyclonal, approximately 68% of CA-MRSA clones were characterised as ST93-IV [2B] (Queensland clone); ST45-V [5C2&5]; ST5-IV [2B]; ST1-IV [2B]; ST30-IV [2B]; and ST97-IV [2B]. As CA-MRSA is well established in the Australian community, it is important to monitor antimicrobial resistance patterns in community- and healthcare-associated SAB as this information will guide therapeutic practices in treating S. aureus bacteraemia.

The LAUsanne STAPHylococcus aureus ENdocarditis (LAUSTAPHEN) score: A prediction score to estimate initial risk for infective endocarditis in patients with S. aureus bacteremia.

Infective endocarditis (IE) is a common complication of Staphylococcus aureus bacteremia (SAB). The study aimed to develop and validate a prediction score to determine IE risk among SAB. This retrospective study included adults with SAB (2015-2021) and divided them into derivation and validation cohorts. Using the modified 2015 European Society of Cardiology modified Duke Criteria for definite IE, the LAUSTAPHEN score was compared to previous scores. Among 821 SAB episodes, 419 and 402 were divided into derivation and validation cohorts, respectively. Transthoracic and transoesophageal echocardiography (TOE) were performed in 77.5 and 42.1% of episodes, respectively. Definite IE was diagnosed in 118 episodes (14.4%). Derivation cohort established that cardiac predisposing factors, such as cardiac implantable electronic devices, prolonged bacteremia ≥48 h, and vascular phenomena were independently associated with IE. In addition to those parameters, native bone and joint infections were used to constitute the LAUSTAPHEN score. LAUSTAPHEN and VIRSTA scores misclassified <4% of IE cases as low risk. Misclassification using POSITIVE and PREDICT scores was >10%. The number of TOEs required to safely exclude IE were 66.9 and 51.6% with VIRSTA and LAUSTAPHEN, respectively. LAUSTAPHEN and VIRSTA scores exhibited the lowest misclassification rate of IE cases to the low-risk group. However, the number of patients requiring TOE was higher for VIRSTA than for LAUSTAPHEN.

Timing of Patient Management Decisions Relative to Echocardiography in Staphylococcus aureus Bacteremia: A Single-Center Retrospective Analysis.

BackgroundIn patients with Staphylococcus aureus bacteremia (SAB), endocarditis evaluation includes transthoracic echocardiography (TTE) and, in patients at increased risk of endocarditis, subsequent transesophageal echocardiography (TEE). Whether performing TTE before TEE influences clinicians’ decision making has not been well studied in patients deemed to warrant TEE.MethodsIn this retrospective case series, we studied clinician behavior at a large Veterans Affairs medical center regarding the care of adult patients diagnosed with SAB who completed both TTE and TEE (n = 206 episodes of SAB). The timing of key patient management decisions was compared to the timing of the patient’s TTE and TEE. It was inferred whether each management decision could have been informed by TTE alone versus TTE plus subsequent TEE. Management decisions included the following: documentation of antibiotic treatment duration, initiation of synergistic antibiotics, consultation of relevant specialists, ordering of relevant imaging studies, and performance of valve surgery or cardiac device explanation.ResultsThe primary outcome (any of the above 5 management decisions taking place) occurred after completion of TTE but before TEE in 13 SAB episodes (6.3%). The primary outcome occurred after completion of both TTE and TEE in 178 SAB episodes (86.4%). Documentation of antibiotic treatment duration accounted for the large majority of observed management decisions.ConclusionsAmong patients with SAB who are deemed to warrant TEE for endocarditis evaluation, TTE results alone rarely prompt clinical management decisions.

Australian Group on Antimicrobial Resistance (AGAR) Australian Staphylococcus aureus Sepsis Outcome Programme (ASSOP) Annual Report 2020.

From 1 January to 31 December 2020, forty-nine institutions around Australia participated in the Australian Staphylococcus aureus Sepsis Outcome Programme (ASSOP). The aims of ASSOP 2020 were to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that were antimicrobial resistant, with particular emphasis on susceptibility to methicillin; and to characterise the molecular epidemiology of the methicillin-resistant isolates. A total of 2,734 SAB episodes were reported, of which 79.7% were community-onset. Of S. aureus isolates, 17.6% were methicillin resistant. The 30-day all-cause mortality associated with methicillin-resistant SAB was 14.2%, which was not significantly different from the 13.3% mortality associated with methicillin-susceptible SAB (p = 0.6). With the exception of the β-lactams and erythromycin, antimicrobial resistance in methicillin-susceptible S. aureus was rare. However, in addition to the β-lactams, approximately 35% of methicillin-resistant S. aureus (MRSA) were resistant to erythromycin, 33% to ciprofloxacin, 13% to tetracycline, 13% to gentamicin and 4% to co-trimoxazole. When applying the European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, teicoplanin resistance was detected in four S. aureus isolates. Resistance was not detected for vancomycin and linezolid. Resistance to non-beta-lactam antimicrobials was largely attributable to two healthcare-associated MRSA (HA-MRSA) clones: ST22-IV [2B] (EMRSA-15) and ST239-III [3A] (Aus-2/3 EMRSA). The ST22-IV [2B] (EMRSA-15) clone is the predominant HA-MRSA clone in Australia. However, 85% percent of methicillin-resistant SAB isolates were community-associated MRSA (CA-MRSA) clones. Although polyclonal, approximately 77% of CA-MRSA clones were characterised as: ST93-IV [2B] (Queensland CA-MRSA); ST5-IV [2B]; ST45-V [5C2&5]; ST1-IV [2B]; ST30-IV [2B]; ST8-IV [2B]; and ST97-IV [2B]. The CA-MRSA clones, in particular ST45-V [5C2&5], have acquired multiple antimicrobial resistance determinants including ciprofloxacin, erythromycin, clindamycin, gentamicin and tetracycline. The multi-resistant ST45-V [5C2&5] clone accounted for 11.0% of CA-MRSA. As CA-MRSA is well established in the Australian community, it is important to monitor antimicrobial resistance patterns in community- and healthcare-associated SAB as this information will guide therapeutic practices in treating S. aureus sepsis.

Incidence of Monomicrobial Staphylococcus aureus Bacteremia: A Population-Based Study in Olmsted County, Minnesota-2006 to 2020.

BackgroundPopulation-based studies of Staphylococcus aureus bacteremia (SAB) in the United States are limited. We provide a contemporary evaluation of SAB incidence in Olmsted County, Minnesota, from 2006 to 2020.MethodsThis was a retrospective population-based study of all adult patients with SAB residing in Olmsted County from 1 January 2006 through 31 December 2020. Initial episodes of SAB were identified using the microbiology laboratory databases at both Olmsted Medical Center and Mayo Clinic Rochester.ResultsOverall, 541 incident SAB cases were identified with a median age of 66.8 (interquartile range, 54.4–78.5) years, and 60.4% were male. Among these cases, 298 (56.2%) were due to methicillin-susceptible S aureus (MSSA) and 232 (43.8%) cases of methicillin-resistant S aureus (MRSA). The overall age- and sex-adjusted SAB incidence rate (IR) was 33.9 (95% confidence interval [CI], 31.0–36.8) cases/100 000 person-years (PY). Males had a higher age-adjusted IR of 46.0 (95% CI, 41.0–51.0) cases/100 000 PY compared to females (IR, 24.4 [95% CI, 21.1–27.7] cases/100 000 PY). Age- and sex-adjusted SAB IRs due to MSSA and MRSA were 18.7 and 14.6 cases/100 000 PY, respectively, and the percentage of incident SAB cases due to MRSA fluctuated across the study period. There was no apparent temporal trend in SAB incidence over the study period (P = .093).ConclusionsOur investigation represents the only contemporary population-based study in the United States. Despite the impression that SAB incidence may have increased based on Centers for Disease Control and Prevention surveillance data, our finding of no change in SAB incidence was somewhat unanticipated.

Complicated and uncomplicated S. aureus bacteraemia: an international Delphi survey among infectious diseases experts on definitions and treatment

ObjectivesClassification of Staphylococcus aureus bacteraemia (SAB) as ‘complicated’ or ‘uncomplicated’ and management of both is based on low-quality evidence. The aim of the study was to determine the degree of agreement among infectious diseases physician experts in the management of patients with SAB. MethodsA stepwise RAND-modified Delphi procedure with two questionnaire rounds was performed. Four aspects of management in 22 clinical scenarios were addressed: (a) classification of SAB episodes; (b) value of combination therapy; and (c) timing of and (d) preferred antibiotics for oral stepdown therapy. ResultsOut of 90 approached experts, 33 (36.7%) from 14 different countries and 5 continents consented to participate. The experts considered any of the discussed implanted foreign material (with no evidence of infection), except for coronary artery stents, as relevant to the classification of a complicated SAB episode. Concerning antibiotic combination therapy, the experts strongly agreed that combination therapy with rifampicin is only relevant in patients with prosthetic valve endocarditis and prosthetic joint infection. The experts considered an oral stepdown therapy in patients with an uncomplicated SAB within 14 days and only thereafter in patients with a complicated SAB episode, but never in patients with prosthetic valve endocarditis. No single antibiotic of choice for oral stepdown therapy could be identified, neither for infections with methicillin-resistant S. aureus nor methicillin-susceptible S. aureus. DiscussionThe Delphi survey can help physicians in their day-to-day decision-making process, and it reveals open questions that must be investigated by further studies.

Epidemiology and Clinical Characteristics of Staphylococcal Bacteremia in Bahrain

Background and Objectives: Staphylococcus aureus bacteremia (SAB) is a significant health problem with high morbidity &amp; mortality. The aim of this study was to evaluate the epidemiology of SAB in Bahrain along with withs clinical characteristics and outcomes. Methods: This study was conducted at Salmaniya medical complex (SMC) microbiology laboratory including all patients with SAB for one year period (2019). Demographic, lab data &amp; outcomes were obtained from the electronic record system of patients. Results: A total of 164 episodes of SAB were identified during the study period. About 137 were encountered among inpatients, while 27 cases among outpatients attending hemodialysis unit. Bahraini nationality &amp; male gender were predominant (141, 85.98% &amp; 108, 65.85% respectively). Nosocomial SAB accounts for only 29.37%, while the majority of SAB cases were of community-onset (116, 70.37%), but among such community-onset cases; 83 (50.61% of total) were of health care-associated category (56 had prior hospitalization and 27 were on regular dialysis). Among all patients with SAB, diabetes was the commonest risk factor encountered, followed by dialysis dependence and sickle cell diseases (SCD). Mortality rate was 25.6% (42 patients). Among the 122 survivors of the initial SAB episode, recurrence of bacteremia was documented among 26 cases (21.3%). Conclusion: SAB was a significant health problem among the Bahraini. Diabetes Mellitus, SCD and dialysis dependence were found to be important risk factors. Recurrence of bacteremia was a common complication among the patient’s dependant on hemodialysis Keywords: Staphylococcus aureus, Bacteremia, Nosocomial, Community onset, Hemodialysis

Forgoing transesophageal echocardiogram in selected patients with complicated Staphylococcus aureus bacteremia.

Infective endocarditis (IE) has been increasingly recognized as an important complication of Staphylococcus aureus bacteremia (SAB), leading to a low threshold for echocardiography and extended treatment with anti-staphylococcal agents. However, outside of IE, many indications for prolonged anti-staphylococcal therapy courses are present. We sought to determine the frequency in which findings from a transesophageal echocardiogram (TEE) changed clinical SAB management in a large Canadian health region. Residents (> 18years) with SAB from 2012 to 2014 who underwent transthoracic echocardiogram (TTE) and TEE were assessed. Patients potentially benefiting from an extended course of anti-staphylococcal agents were defined a priori. Patient demographics, treatment (including surgical), and clinical outcomes were extracted and evaluated. Of the 705 episodes of SAB that underwent a screening echocardiogram, 203 episodes underwent both a TTE and TEE, of which 92.1% (187/203) contained an a priori indication for extended anti-staphylococcal therapy. Regardless of TEE results, actual duration of therapy did not differ in SAB episodes that had ≥ 1 extended anti-staphylococcal therapy criteria (36.7days, IQR 23.4-48.6 vs. 43.8days, IQR 33.3-49.5, p = 0.17). Additionally, there were no cases in which TEE was utilized as the sole reason to shorten duration of therapy or proceed to surgery for those with SAB. Routine performance of TEE may be unnecessary in all SAB as many patients have pre-existing indications for extended anti-staphylococcal therapy independent of TEE findings. An algorithm to selectively identify cases of SAB that would benefit from TEE can reduce resource and equipment expenditure and patient risks associated with TEE.

Impact of a Best Practice Advisory for Pediatric Patients With Staphylococcus aureus Bacteremia.

Infectious diseases (ID) consultation and optimal antibiotic therapy improve outcomes in Staphylococcus aureus bacteremia (SAB). Data on strategies to improve adherence to these practices in children are limited. This was a quasi-experimental study evaluating the impact of an electronic medical record (EMR)-based best practice advisory (BPA) for SAB, recommending ID consult and optimal antibiotic therapy based on rapid mecA gene detection. Inpatients < 21 years old with SAB before (January 2015-July 2017) and after (August 2017-December 2018) BPA implementation were included. Primary outcome was receipt of ID consult. Secondary outcomes included receipt of optimal therapy, time to ID consult and optimal therapy, recurrent SAB, and 30-day all-cause mortality. ID consultation rates pre- and postimplementation were compared using interrupted time series (ITS) analysis. Hazard ratios (HRs) and 95% confidence intervals (CIs) for time to optimal therapy were calculated using Cox regression. We included 99 SAB episodes (70 preintervention, 29 postintervention). Preintervention, 48 (68.6%) patients received an ID consult compared to 27 (93.1%) postintervention, but this was not statistically significant on ITS analysis due to a preexisting trend of increasing consultation. Median hours to optimal therapy decreased from 26.1 to 5.5 (P = .03), most notably in patients with methicillin-sensitive S. aureus (MSSA) (42.2 to 10.8; P < .01). On Cox regression, BPA implementation was associated with faster time to optimal therapy (HR, 3.22 [95% CI, 1.04-10.01]). Implementation of an EMR-based BPA for SAB resulted in faster time to optimal antibiotic therapy, particularly for patients with MSSA. ID consultation increased throughout the study period and was not significantly impacted by the BPA.

Australian Group on Antimicrobial Resistance (AGAR) Australian Staphylococcus aureus Sepsis Outcome Programme (ASSOP) Annual Report 2018.

From 1 January to 31 December 2018, thirty-six institutions around Australia participated in the Australian Staphylococcus aureus Sepsis Outcome Programme (ASSOP). The aim of ASSOP 2018 was to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that are antimicrobial resistant, with particular emphasis on susceptibility to methicillin, and to characterise the molecular epidemiology of the methicillin-resistant isolates. A total of 2,673 S. aureus bacteraemia episodes were reported, of which 78.9% were community-onset. A total of 17.4% of S. aureus isolates were methicillin resistant. The 30-day all-cause mortality associated with methicillin-resistant SAB was 17.1% which was not significantly higher than the 13.6% mortality associated with methicillin-susceptible SAB (p = 0.1). With the exception of the β-lactams and erythromycin, antimicrobial resistance in methicillin-susceptible S. aureus was rare. However in addition to the β-lactams approximately 42% of methicillin-resistant S. aureus (MRSA) were resistant to erythromycin, 36% to ciprofloxacin and approximately 13% resistant to co-trimoxazole, tetracycline and gentamicin. When applying the EUCAST breakpoints teicoplanin resistance was detected in two S. aureus isolates. Resistance was not detected for vancomycin and linezolid. Resistance to non-beta-lactam antimicrobials was largely attributable to two healthcare-associated MRSA clones: ST22-IV [2B] (EMRSA-15) and ST239-III [3A] (Aus-2/3 EMRSA). The ST22-IV [2B] (EMRSA-15) clone is the predominant healthcare-associated clone in Australia. Seventy-eight percent of methicillin-resistant SAB episodes in 2018 were due to community-associated clones. Although polyclonal, approximately 76.3% of community-associated clones were characterised as ST93-IV [2B] (Queensland CA-MRSA), ST5-IV [2B], ST45-VT [5C2&5], ST1-IV [2B], ST30-IV [2B], ST78-IV [2B] and ST97-IV [2B]. Community-associated MRSA, in particular the ST45-VT [5C2&5] clone, has acquired multiple antimicrobial resistance determinants including ciprofloxacin, erythromycin, clindamycin, gentamicin and tetracycline. The ST45-VT [5C2&5] clone accounted for 11.7% of CA-MRSA. As CA-MRSA is well established in the Australian community, it is important that antimicrobial resistance patterns in community- and healthcare-associated SAB are monitored, as this information will guide therapeutic practices in treating S. aureus sepsis.

A review of the utility of PET imaging in Staphylococcus aureus bacteraemia (SAB) using electronic data

Introduction: If the infectious focus is not identified, there is an associated higher mortality in Staphylococcus aureus bacteraemia (SAB) [1]. A retrospective observational study found patients with high-risk SAB who had a PET scan had a 67% reduction in mortality compared to those who did not [2]. We used electronic data to determine the range of infectious foci in SAB and the use of PET in our trust. Methods: From 1/1/13 to 31/12/18 all patients with SAB at St Thomas’ Hospital, London, were reviewed by the infectious diseases team and data collected prospectively using an Access database. A retrospective analysis of this database, electronic records, radiology and nuclear imaging was conducted. Results: 355 episodes of SAB affected 296 patients. 28 (8%) episodes were MRSA in 24 (8%) of patients. Infectious sources found included bone and joint (23%), IV access (15%), vascular infection (15%), no infective focus (13%), SSTI (12%) and endocarditis (9%). Imaging used to determine the focus of infection included MRI (18%), CT (26%) and PET scan (10%). In-hospital mortality was significantly lower in those who had a PET scan than in those who did not (1/31, 3% v. 50/265 patients (last episode), 19%, P=0.03). Conclusions: Mortality was lower in those who had PET at our trust. This is consistent with data published from other centres and requires further investigation. A prospective trial of PET in SAB is urgently needed.

Intermittent Negative Blood Cultures in Staphylococcus aureus Bacteremia; a Retrospective Study of 1071 Episodes.

BackgroundRecommended management of Staphylococcus aureus bacteremia (SAB) includes follow-up blood culture sets (BCs) to determine the duration of bacteremia. Duration of bacteremia is an important prognostic factor in SAB, and follow-up BCs have a critical role in differentiation of uncomplicated and complicated SAB. However, intermittent negative BCs occur in SAB. Clinical guidelines for SAB management do not specify an approach to follow-up BCs’ collection or define the number of negative BCs required to demonstrate resolution of bacteremia. This study assessed the frequency of intermittent negative BCs in SAB and used these findings to formulate a recommendation for collection of follow-up BCs.MethodsThis retrospective study reviewed 1071 episodes of SAB. Clinical and microbiological data including the duration of bacteremia and the occurrence of intermittent negative BCs (those preceded and followed by positive cultures) were considered.ResultsIntermittent bacteremia occurred in 13% (140/1071) of episodes. A single negative BC on days 1–3 had a predictive value of 87%–93% for resolution of bacteremia, although this was improved if all BCs collected within the same day were considered.ConclusionsIntermittent negative BCs are common in SAB. Given this, we would not recommend accepting a single negative BC as demonstrating resolution of the bacteremia. This is particularly important if a patient is to be classified as having uncomplicated SAB.

209. What’s So Complicated About Complicated Staphylococcus aureus Bacteremia: Does Day 5 Matter?

BackgroundProlonged Staphylococcus aureus bacteremia (SAB) poses challenges in clinical practice, particularly when a source is not readily identified. While SAB greater than 3 days has been identified as a risk factor for complications, little is known about risk for specific complications with each successive day of bacteremia. We sought to determine the risk for specific complications with the duration of bacteremia.MethodsWe retrospectively reviewed all cases of SAB between 1 January 2017 and 31 December 2017 at a 500-bed academic hospital. Adult patients (≥18 years) with at least one blood culture positive for S. aureus were identified. Patients were excluded if withdrawal of care or death occurred within 48 hours of blood culture results or if the infection was associated with a ventricular assist device. Medical records were reviewed for the duration of bacteremia, complications, treatment decisions and clinical outcomes. This study was approved by the Institutional Review Board.ResultsOne hundred forty-two discrete episodes of SAB were identified with a median age of 54 years (IQR 40–63). Most cases were community-acquired (83.8%) and 33.8% were MRSA. Active injection drug use was present in 22.5% (33.3% MRSA, 17% MSSA). The median duration of bacteremia was 2.6 days (IQR 1.8–4.6) and 3.9 days (IQR 2.2–7.5) for MSSA and MRSA, respectively. The median time to first source control procedure was twice as long with bacteremia over 5 days than with a shorter duration of bacteremia (2.6 vs. 1.3 days). Complication rates increased with bacteremia duration and bacteremia longer than 5 days was associated with significantly higher rates of endocarditis (46.2%, P < 0.001), epidural abscesses (35.9%, P = 0.001), intracranial infections (12.8%, P = 0.02), and presence of at least one endovascular nidus (76.9%, P < 0.001) compared with bacteremia less than 5 days (28.4%), but 30 day mortality rates were similar (7.7% and 9.8%, respectively).ConclusionComplication rates increase significantly with SAB greater than 5 days duration. Early source control and investigation to identify metastatic and especially endovascular foci of infection are paramount in patients with prolonged bacteremia even if complications are not discovered on initial evaluation. Disclosures All authors: No reported disclosures.

Clinical utility of echocardiography for the diagnosis of native valve infective endocarditis in Staphylococcus aureus bacteremia.

The incidence of Staphylococcus aureus infective endocarditis (IE) is steadily rising due to advances in health care delivery. Routine echocardiography is essential in the management of Staphylococcus aureus bacteremia (SAB). The aim of this retrospective cohort study was to characterize the real-world use of echocardiography in adult patients with SAB and native valve Saureus IE. Using an academic hospital microbiological database, all cases of SAB in adults between 2010 and 2016 were identified. Demographic, echocardiographic, and clinical features were recorded. A total of 738 episodes of SAB were identified, of which 504 (68%) patients underwent transthoracic echocardiography (TTE) within 30days. Of 73 patients with definite IE, 46 (63%) patients had definite IE diagnosed on the initial TTE. An additional 14 (19%) patients had definite IE diagnosed on repeat TTE, 6 (8%) on transesophageal echocardiography (TEE), and 7 (10%) were diagnosed without fulfilling Duke echocardiographic criteria. The yield of repeat TTE was comparable to that of TEE for identifying new vegetations not identified on the initial TTE (17% vs 21%, P=.78). Most cases of IE in SAB were identified using TTE alone, with repeat TTE improving the diagnostic yield in the setting of clinical decompensation.

Epidemiology and Outcome Determinants of Staphylococcus aureus Bacteremia Revisited: A Population-Based Study.

Staphylococcus aureus bacteremia (SAB) is associated with significant morbidity and mortality. We sought to re-define the burden, epidemiology and mortality-associated risk factors of SAB in a large Canadian health region. Residents (> 18years) experiencing SAB from 2012 to 2014 were assessed. Incidence rates were calculated using civic census results. Factors associated with 30-day mortality were determined through multivariate logistic regression. Incidence and risk factors for SAB were compared to 2000-2006 data. 780 residents experienced 840 episodes of SAB (MRSA; 20%). Incidence rates increased from 23.5 to 32.0 cases/100,000 from 2012 to 2014; [IRR 1.15 (95% CI 1.07-1.23); p < 0.001]. Compared to a decade ago, incidence of SAB has increased [IRR 1.28 (95% CI 1.21-1.36); p < 0.001] despite minimal change in nosocomial SAB. MRSA proportion did not change through the study (p = 0.3), but did increase relative to a decade ago (20.0% vs 11.0%, p < 0.001). Thirty-day mortality rates were 30.6% and 21.3% for MRSA and MSSA, respectively (p = 0.01), similar to rates from 2000 to 2006. Several clinical, demographic, and biochemical factors were independently associated with SAB mortality. SAB is common within our population resulting in significant mortality. Incidence rates of SAB are increasing in our health region; however, 30-day mortality rates remain stable.

Infectious diseases consultation improves key performance metrics in the management of Staphylococcus aureus bacteremia: A multicentre cohort study.

Staphylococcus aureus bacteremia (SAB) is associated with significant morbidity and mortality. We sought to identify factors associated with infectious diseases consultation (IDC) and understand how IDC associates with SAB patient management and outcomes. A multicentre retrospective study was performed between 2012 and 2014 in a large Canadian Health Zone in order to determine factors associated with IDC and performance of key quality of care determinants in SAB management and clinical outcomes. Factors subject to quality of care determinants were established a priori and studied for associations with IDC and 30-day all-cause mortality using multivariable analysis. Of 961 SAB episodes experienced by 892 adult patients, 605 episodes received an IDC. Patients receiving IDC were more likely to have prosthetic valves and joints and to have community-acquired and known sources of SAB, but increasing age decreased IDC occurrence. IDC was the strongest independent predictor for quality of care performance metrics, including repeat blood cultures and echocardiography. Mortality at 30 days was 20% in the cohort, and protective factors included IDC, achievement of source control, targeted therapy within 48 hours, and follow-up blood cultures but not the performance of echocardiography. There were significant gaps between the treatments and investigations that patients actually received for SAB and what is considered the optimal management of their condition. IDC is associated with improved attainment of targeted SAB quality of care determinants and reduced mortality rates. Based on our findings, we propose a policy of mandatory IDC for all cases of SAB to improve patient management and outcomes.