Community-onset Bloodstream Infections Research Articles

An emergency department intervention to improve earlier detection of community-onset bloodstream infection among hospitalized patients

Blood cultures (BCs) are essential microbiologic tests, but blood culturing diagnostic stewardship is frequently poor. We aimed to study the process-related failures and to evaluate the effect of an emergency department (ED) intervention on BCs collection practices and yield. We implemented an ED-quality improvement intervention including educational sessions, phlebotomists addition, promoting single-site strategy for BC-collection and preanalytical data feedback. BC-bottles collected, positive BCs, blood volumes and documentation of collection times were measured, before (December 2021-August 2022) and after (September 2022-July 2023) intervention. Results were corrected to hospitalizations admissions or days. We used interrupted-time series analyses for comparisons. A total of 64,295 BC bottles were evaluated, 26,261 before and 38,034 postintervention. The median ED-BCs collected per week increased from 88 to 105 BCs (P<.0001), resulting from increased early sampling (P=.0001). Solitary BCs decreased (95%-28%), documented times increased (2.8%-25%), and average blood volume increased (3mL to 4.5mL) postintervention. Community-onset Bloodstream infections (BSIs) increased (39.6-52 bottles/1,000 admissions, P=.0001), while Health care-associated BSIs decreased (39-27 bottles/10,000 days, P=.0042). Contamination rates did not change. An ED-focused intervention based on the education sessions and single-site strategy improved culturing stewardship and facilitated the early identification of BSI without an increase in contamination.

Acute kidney injury should not be neglected - optimization of quick Pitt bacteremia score for predicting mortality in critically ill patients with bloodstream infection: a retrospective cohort study.

Considering the therapeutic difficulties and mortality associated with bloodstream infection (BSI), it is essential to investigate other potential factors affecting mortality in critically ill patients with BSI and examine the utility of the quick Pitt bacteremia (qPitt) score to improve the survival rate. To improve the predictive accuracy of the qPitt scoring system by evaluating the five current components of qPitt and including other potential factors influencing mortality in critically ill patients with BSI. This was a retrospective cohort study. Medical information from the Medical Information Mart for Intensive Care IV database was used in this retrospective cohort study. The risk factors associated with mortality were examined using a multivariate logistic regression model. The area under the receiver operating characteristic curve (AUC) was used to assess the discriminatory capability of the prediction models. In total, 1240 eligible critically ill patients with BSI were included. After adjustment for age, community-onset BSI, indwelling invasive lines, and Glasgow Coma Scale (GCS) ⩽ 8, acute kidney injury (AKI) was identified as a notable risk factor for 14-day mortality. Except for altered mental status, the four other main components of the original qPitt were significantly associated with 14-day mortality. Hence, we established a modified qPitt (m-qPitt) by adding AKI and replacing altered mental status with GCS ⩽ 8. The AUCs for m-qPitt and qPitt were 0.723 [95% confidence interval (CI): 0.683-0.759] and 0.708 (95% CI: 0.669-0.745) in predicting 14-day mortality, respectively. Moreover, m-qPitt also had acceptable performance and discrimination power [0.700 (95% CI: 0.666-0.732)] in predicting 28-day mortality. AKI significantly influenced the survival of critically ill patients with BSIs. Compared with the original qPitt, our new m-qPitt was proven to have a better predictive performance for mortality in critically ill patients with BSI. Further studies should be conducted to validate the practicality of m-qPitt.

From Epidemiology of Community-Onset Bloodstream Infections to the Development of Empirical Antimicrobial Treatment-Decision Algorithm in a Region with High Burden of Antimicrobial Resistance.

Antimicrobial-resistant (AMR) infections have increased in community settings. Our objectives were to study the epidemiology of community-onset bloodstream infections (BSIs), identify risk factors for AMR-BSI and mortality-related factors, and develop the empirical antimicrobial treatment-decision algorithm. All adult, positive blood cultures at the emergency room and outpatient clinics were evaluated from 08/2021 to 04/2022. AMR was defined as the resistance of organisms to an antimicrobial to which they were previously sensitive. A total of 1151 positive blood cultures were identified. There were 450 initial episodes of bacterial BSI, and 114 BSIs (25%) were AMR-BSI. Non-susceptibility to ceftriaxone was detected in 40.9% of 195 E. coli isolates and 16.4% among 67 K. pneumoniae isolates. A treatment-decision algorithm was developed using the independent risk factors for AMR-BSI: presence of multidrug-resistant organisms (MDROs) within 90 days (aOR 3.63), prior antimicrobial exposure within 90 days (aOR 1.94), and urinary source (aOR 1.79). The positive and negative predictive values were 53.3% and 83.2%, respectively. The C-statistic was 0.73. Factors significantly associated with 30-day all-cause mortality were Pitt bacteremia score (aHR 1.39), solid malignancy (aHR 2.61), and urinary source (aHR 0.30). In conclusion, one-fourth of community-onset BSI were antimicrobial-resistant, and one-third of Enterobacteriaceae were non-susceptible to ceftriaxone. Treatment-decision algorithms may reduce overly broad antimicrobial treatment.

179. From Epidemiology of Community-onset Bloodstream Infections to the Development of Empirical Antimicrobial Treatment-decision Algorithm in a Region with High Burden of Antimicrobial Resistance

Abstract Background More antimicrobial-resistant (AMR) infections have emerged in community settings. Our objectives were to study the epidemiology of community-onset bloodstream infections (BSIs), identify risk factors for AMR-BSI and factors associated with mortality, and develop the empirical antimicrobial treatment-decision algorithm. Methods A retrospective cohort study was conducted at a tertiary-care hospital. All positive blood cultures from adult patients at the emergency room and outpatient clinics were identified from 1 Aug 2021-15 Apr 2022. AMR was defined as the resistance of organisms to an antimicrobial to which they were at first sensitive. Risk factors associated with AMR-BSI and factors associated with 30-day mortality were determined. The independent risk factors for AMR-BSI were placed into steps to create an empirical treatment-decision algorithm. C-statistics were calculated. The internal validation cohort was evaluated. Results A total of 1,151 positive blood cultures were identified. There were 450 initial episodes of bacterial BSI, and 114 BSIs (25%) were AMR-BSI. Nonsusceptibility to ceftriaxone was detected in 40.9% of 195 E. coli isolates and 16.4% among 67 K. pneumoniae isolates. A treatment-decision algorithm was developed based on the independent risk factors for AMR-BSI: the presence of multidrug-resistant organisms (MDROs) within 90 days (aOR 3.63; 95% CI 1.95-6.75; P&amp;lt; 0.001), prior antimicrobial exposure within 90 days (aOR 1.94; 95% CI 1.08-3.50; P=0.03), and urinary source (aOR 1.79; 95% CI 1.06-3.01; P=0.03). The positive and negative predictive values were 53.3% (95% CI 45.4-61.1%) and 83.2% (95% CI 80.4-85.6%), respectively. The C-statistic was 0.73. Factors significantly associated with 30-day all-cause mortality were Pitt bacteremia score (aHR 1.39; 95% CI 1.20–1.62; P&amp;lt; 0.001), solid malignancy (aHR 2.61; 95% CI 1.30–5.24; P=0.01), and urinary source (aHR 0.30; 95% CI 0.11–0.79; P=0.02). Univariable analysis and multivariable analysis of risk factors for antimicrobial resistance Proposed empirical antimicrobial treatment algorithm for patients with suspected community-onset bloodstream infections Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and C-statistics of the algorithm in predicting antimicrobial resistant infection Conclusion One-fourth of community-onset BSI were antimicrobial-resistant, and almost one-third of Enterobacteriaceae were nonsusceptible to ceftriaxone. Treatment-decision algorithm based on the presence of MDROs within 90 days, prior antimicrobial use within 90 days, and the urinary source may reduce overly broad antimicrobial treatment. Disclosures All Authors: No reported disclosures

Risk and Outcome of Infective Endocarditis in Streptococcal Bloodstream Infections according to Streptococcal Species.

This study aimed to identify which streptococcal species are closely associated with infective endocarditis (IE) and to evaluate risk factors for mortality in patients with streptococcal IE. We performed a retrospective cohort study of all patients with streptococcal bloodstream infection (BSI) from January 2010 to June 2020 in a tertiary hospital in South Korea. We compared clinical and microbiological characteristics of streptococcal BSIs according to the diagnosis of IE. We performed multivariate analysis to evaluate the risk of IE according to streptococcal species and risk factors for mortality in streptococcal IE. A total of 2,737 patients were identified during the study period, and 174 (6.4%) were diagnosed with IE. The highest IE prevalence was in patients with Streptococcus mutans BSI (33% [9/27]) followed by S. sanguinis (31% [20/64]), S. gordonii (23% [5/22]), S. gallolyticus (16% [12/77]), and S. oralis (12% [14/115]). In multivariate analysis, previous IE, high-grade BSI, native valve disease, prosthetic valve, congenital heart disease, and community-onset BSI were independent risk factors for IE. After adjusting for these factors, S. sanguinis (adjusted OR [aOR], 7.75), S. mutans (aOR, 5.50), and S. gallolyticus (aOR, 2.57) were significantly associated with higher risk of IE, whereas S. pneumoniae (aOR, 0.23) and S. constellatus (aOR, 0.37) were associated with lower risk of IE. Age, hospital-acquired BSI, ischemic heart disease, and chronic kidney disease were independent risk factors for mortality in streptococcal IE. Our study points to significant differences in the prevalence of IE in streptococcal BSI according to species. IMPORTANCE Our study of risk of infective endocarditis in patients with streptococcal bloodstream infection demonstrated that Streptococcus sanguinis, S. mutans, and S. gallolyticus were significantly associated with higher risk of infective endocarditis. However, when we evaluated the performance of echocardiography in patients with streptococcal bloodstream infection, patients with S. mutans and S. gordonii bloodstream infection had a tendency of low performance in echocardiography. There are significant differences in the prevalence of infective endocarditis in streptococcal bloodstream infection according to species. Therefore, performing echocardiography in streptococcal bloodstream infection with a high prevalence of, and significant association with, infective endocarditis is desirable.

Bloodstream Infection and Colorectal Cancer Risk in Queensland Australia, 2000-2019

BackgroundBloodstream infections may occur as a complication of colorectal cancer or be a marker for its occult presence. The objectives of this study were to quantify the overall and etiology-specific risks for incident colorectal cancer-associated bloodstream infection. MethodsPopulation-based surveillance for community-onset bloodstream infection was conducted among adults aged 20 years and older in Queensland, Australia between 2000 and 2019. Statewide databases were used to identify patients with incident colorectal cancer and collect clinical and outcome information. ResultsAfter exclusion of 1794 patients with prior colorectal cancer, a cohort of 84,754 patients was assembled, of which 1030 had colorectal cancer-associated bloodstream infection and 83,724 had no colorectal cancer. Bloodstream infection was associated with a 16-fold annualized increased risk for diagnosis of colorectal cancer (incidence rate ratio 16.1; 95% confidence interval [CI], 15.1-17.1) in the adult population. Patients who had colorectal cancer-associated bloodstream infection were more likely to be older and male, have hospital-onset and polymicrobial infections, and have fewer non-cancer-related comorbidities. The organisms associated with highest risk for colorectal cancer included Clostridium species (relative risk [RR] 6.1; 95% CI, 4.7-7.9); especially C. septicum (RR 25.0; 95% CI, 16.9-35.7), Bacteroides species (RR 4.7; 95% CI, 3.8-5.8); especially B. ovatus (RR 11.8; 95% CI, 2.4-34.5), Gemella species (RR 6.5; 95% CI, 3.0-12.5), Streptococcus bovis group (RR 4.4; 95% CI, 2.7-6.8); especially S. infantarius subsp. coli (RR 10.6; 95% CI, 2.9-27.3), Streptococcus anginosus group (RR 1.9; 95% CI, 1.3-2.7), and Enterococcus species (RR 1.4; 95% CI, 1.1-1.8). ConclusionAlthough much attention has been afforded to S. bovis group over the past decades, there are many other isolates associated with higher risk for colorectal cancer-associated bloodstream infections.

Community-onset anaerobic bloodstream infection, predisposing factors, and impact on survival: A prospective cohort study

BackgroundFew studies have examined the outcomes and predisposing risk factors for anaerobic bloodstream infections (BSIs). ObjectiveTo determine the survival impact of aerobic versus anaerobic BSI, a prospective cohort study was conducted. MethodsWe prospectively enrolled emergency department patients at a tertiary medical center with BSIs determined by laboratory testing between 2015 and 2016. Anaerobic and aerobic BSIs were compared for demographics, comorbidities, and sources of infection. Several independent risk factors were identified in a multivariable logistic regression model. Using propensity score (PS) matched data, an analysis of survival effects associated with anaerobic BSI has been conducted. ResultsOver a 2-year period, there were 1,166 episodes of BSI, of which 61 (5.2%) occurred as anaerobic episodes. Anaerobic BSIs were strongly associated with intra-abdominal infection (odds ratio [OR] 6.03, 95%CI 2.78–13.09), liver abscess (OR 3.92, 95%CI 1.47–10.45), skin and soft-tissue infection (OR 2.65, 95%CI 1.26–5.62), and metastatic cancer (OR 2.40, 95%CI 1.13–5.08) as the main positive predictors. Negative predictors included diabetes mellitus (OR 0.38, 95%CI 0.18–0.78), thrombocytopenia (OR 0.33, 95%CI 0.18–0.60), and urinary tract infection (OR 0.15, 95%CI 0.04–0.62). Anaerobic BSIs were not associated with worse prognosis after PS-matched analysis (hazard ratio [HR] 1.40, 95%CI 0.44–4.41) in our cohort. ConclusionsA significant percentage of community-onset BSI was due to anaerobic BSI. Anaerobic BSI can have a detrimental outcome if there are underlying comorbidities, high-risk infection sites, and inappropriate antibiotic choices. The findings of our study may contribute to the prescription of empiric anti-anaerobe antibiotics.

A DESCRIPTIVE REVIEW OF RELATIONSHIP OF URINARY TRACT INFECTIONS WITH HEALTHCARE-ASSOCIATED AND COMMUNITY-ONSET BLOODSTREAM INFECTIONS

Background: Bloodstream Infections (BSIs) that arise secondary to urinary tract infections (UTIs) are frequently encountered in both community and hospital settings and are associated with significant morbidity, mortality, high healthcare costs and prolonged hospital stays Objective: This descriptive review aims to evaluate available information on the relationship of urinary tract infections with healthcare-associated and community-onset bloodstream infections to get a deeper understanding of improved public health interventions and suggest possibilities for future research. Methods: A literature search was conducted using PubMed and Embase. Articles published during the last 10 years (2010 and 2020) were imported into providence for the initial title and abstract screening. All study abstracts were reviewed by two independent reviewers and were eligible for full-text review if they mentioned urinary tract infection as a source of bloodstream infection. The data obtained were analyzed in Microsoft Excel. Results: Out of 65 articles reviewed for full text, 10 studies were selected. In total 6763 BSI cases were reported. We observed 2075 (30.6%) community-acquired (CA) BSIs compared to 1102 (16.2%) healthcare-associated (HCA) BSIs, and 1484 (21.9%) hospital-acquired (HA) BSIs. UTI was a major source of BSIs in community settings followed by HCA BSIs in most studies. Escherichia. coli was the most common pathogen isolated in patients with CA-BSIs. Hospital Acquired and HCA bacterial infections have the most antimicrobial resistance, compared to CA-infections. Conclusion: Urinary tract Infections are a major source of developing secondary BSIs. Escherichia. coli is a major pathogen in CA-BSIs. Multidrug-resistant organisms accounted for most of the BSIs, especially in hospital settings and among patients receiving health care. Keywords: Bloodstream infection, UTI, Hospital Acquired, Community Acquired

Risk factors and outcome due to extended-spectrum β-lactamase-producing uropathogenic Escherichia coli in community-onset bloodstream infections: A ten-year cohort study in Sweden.

To study clinical outcome and risk factors associated with extended-spectrum β-lactamase (ESBL)-producing uropathogenic Escherichia coli (UPEC) in community-onset bloodstream infections (CO-BSI). This was a population-based cohort study including patients with pheno- and genotype-matched ESBL-producing E. coli and non-ESBL- E. coli in urine and blood samples collected in 2009-2018 in southeast Sweden. Seventy-seven episodes of ESBL-UPEC satisfying the inclusion criteria were matched 1:1 with 77 non-ESBL-UPEC for age, gender, and year of culture. The most common ST-type and ESBL gene was ST131 (55%), and blaCTX-M-15 (47%), respectively. Risk factors for ESBL-UPEC were: previous genitourinary invasive procedure (RR 4.66; p = 0.005) or history of ESBL-producing E. coli (RR 12.14; p = 0.024). There was significant difference between ESBL-UPEC and non-ESBL-UPEC regarding time to microbiologically appropriate antibiotic therapy (27:15 h vs. 02:14 h; p = <0.001) and hospital days (9 vs. 5; p = <0.001), but no difference in 30-day mortality (3% vs. 3%; p = >0.999) or sepsis within 36 hours (51% vs. 62%; p = 0.623) was observed. The predominant risk factors for ESBL-UPEC were history of ESBL-Ec infection and history of genitourinary invasive procedure. The overall mortality was low and the delay in appropriate antibiotic therapy did not increase the risk for 30-day mortality or risk for sepsis within 36 hours among patients infected with ESBL UPEC. However, these results must be regarded with some degree of caution due to the small sample size.

Community-onset urosepsis: incidence and risk factors for 30-day mortality – a retrospective cohort study

Background Urosepsis is a life-threatening condition that needs to be addressed without delay. Two critical issues in its management are: (1) Appropriate empirical antibiotic therapy, considering the patients general condition, comorbidity, and the pathogen expected; and (2) Timing of imaging to identify obstruction requiring decompression. Objectives To identify risk factors associated with 30-day mortality in patients with urosepsis. Methods From a cohort of 1,605 community-onset bloodstream infections (CO-BSI), 282 patients with urosepsis were identified in a Swedish county 2019–2020. Risk factors for mortality with crude and adjusted odds ratios were analysed using logistic regression. Results Urosepsis was found in 18% (n = 282) of all CO-BSIs. The 30-day all-cause mortality was 14% (n = 38). After multivariable analysis, radiologically detected urinary tract disorder was the predominant risk factor for mortality (OR = 4.63, 95% CI = 1.47–14.56), followed by microbiologically inappropriate empirical antibiotic therapy (OR = 4.19, 95% CI = 1.41–12.48). Time to radiological diagnosis and decompression of obstruction for source control were also important prognostic factors for survival. Interestingly, 15% of blood cultures showed gram-positive species associated with a high 30-day mortality rate of 33%. Conclusion The 30-day all-cause mortality from urosepsis was 14%. The two main risk factors for mortality were hydronephrosis caused by obstructive stone in the ureter and inappropriate empirical antibiotic therapy. Therefore, early detection of any urinary tract disorder by imaging followed by source control as required, and antibiotic coverage of both gram-negative pathogens and gram-positive species such as E. faecalis to optimise management, is likely to improve survival in patients with urosepsis.

Achromobacter Species: An Emerging Cause of Community-Onset Bloodstream Infections.

Background: Case reports and small series indicate that Achromobacter species bloodstream infection (BSI) is most commonly a complication of hospitalization among patients with chronic lung disease. The aim of the present study was to determine the incidence, risk factors, and outcomes of Achromobacter sp. BSI in an Australian population. Methods: Retrospective, laboratory-based surveillance was conducted in Queensland, Australia (population ≈ 5 million) during 2000–2019. Clinical and outcome data were obtained by linkage to state hospital admissions and vital statistics databases. BSI diagnosed within the community or within the first two calendar days of stay in hospital were classified as community-onset. Community-onset BSIs were grouped into community-associated and healthcare-associated. Results: During more than 86 million person-years of surveillance, 210 incidents of Achromobacter sp. BSI occurred among 195 individuals for an overall age-and sex-standardized annual incidence of 2.6 per million residents. Older individuals and males were at highest risk (2.9 vs. 2.0 per million, IRR for males 1.5; 95% CI, 1.1–1.9; p = 0.008). Most (153; 73%) cases were of community-onset of which 100 (48%) and 53 (25%) were healthcare- and community-associated, respectively. An increasing proportion of community-onset cases were observed during twenty years of surveillance. Underlying medical illnesses were common with median (interquartile range) Charlson Comorbidity Index (CCI) scores of 3 (1–5). CCI scores of 0, 1, 2, and 3+ were observed in 37 (18%), 27 (13%), 40 (19%), and 105 (50%) of cases, respectively. All but one of the cases were admitted to hospital for a median (interquartile range) length of stay of 12 (5–34) days. All-cause case–fatality rates in hospital by day 30 and by day 90 were 30 (14%), 28 (13%), and 42 (20%), respectively. The 90-day case–fatality rate increased with increasing comorbidity and was 3% (1/37), 11% (3/27), 25% (10/40), and 27% (28/105) among those with Charlson Comorbidity Indices of 0, 1, 2, and 3+, respectively (p = 0.004). Conclusions: Although comorbidity is an important determinant of risk, most Achromobacter sp. BSI are of community-onset and one-fifth of cases occur in patients without significant underlying chronic co-morbidities. This study highlights the value of population-based methodologies to define the epidemiology of an infectious disease.

Escherichia coli ST1193: Following in the Footsteps of E. coli ST131.

Escherichia coli ST1193 is an emerging global multidrug (MDR) high-risk clone and an important cause of community-onset urinary and bloodstream infections. ST1193 is imitating E. coli ST131, the most successful MDR clone of all time. Both clones emerged in the early 1990s by acquiring quinolone resistance-determining region (QRDR) mutations, IncF plasmids, virulence factors, and type 1 pilus (fimH) recombination. They are the only MDR clones that are dominant among unselected E. coli populations. ST131 is the most frequent clone and ST1193 the second most frequent clone among fluoroquinolone/cephalosporin-resistant E. coli isolates. Both clones have played pivotal roles in the global spread of MDR E. coli. ST1193 originated from ST clonal complex 14 (STc14), is lactose nonfermenting, belongs to phylogenetic group B2, and contains the O type O75. Global ST1193 prevalence has been increasing since 2012, even replacing ST131 in certain regions. blaCTX-M genes are rapidly expanding among ST1193 isolates, a scenario that occurred with ST131 during the 2000s. A validated PCR will enable global surveys to determine the extent of ST1193 among One Health E. coli isolates. The rapid emergence of ST1193 is concerning and is adding to the public health burden of MDR E. coli clones. Basic mechanistic, evolutionary, surveillance, and clinical studies are urgently required to investigate the success of ST1193. Such information will aid with management and prevention strategies. The medical community can ill afford to ignore the spread of another global successful MDR high-risk E. coli clone, especially one that is following in the footsteps of E. coli ST131.

Pseudomonas aeruginosa Community-Onset Bloodstream Infections: Characterization, Diagnostic Predictors, and Predictive Score Development-Results from the PRO-BAC Cohort.

Community-onset bloodstream infections (CO-BSI) caused by gram-negative bacilli are common and associated with significant mortality; those caused by Pseudomonas aeruginosa are associated with worse prognosis and higher rates of inadequateempirical antibiotic treatment. The aims of this study were to describe the characteristics of patients with CO-BSI caused by P. aeruginosa, to identify predictors, and to develop a predictive score for P. aeruginosa CO-BSI. Materials/methods: PROBAC is a prospective cohort including patients >14 years with BSI from 26 Spanish hospitals between October 2016 and May 2017. Patients with monomicrobial P. aeruginosa CO-BSI and monomicrobial Enterobacterales CO-BSI were included. Variables of interest were collected. Independent predictors of Pseudomonas aeruginosa CO-BSI were identified by logistic regression and a prediction score was developed. Results: A total of 78patients with P. aeruginosa CO-BSI and 2572 with Enterobacterales CO-BSI were included. Patients with P. aeruginosa had a median age of 70 years (IQR 60–79), 68.8% were male, median Charlson score was 5 (IQR 3–7), and 30-daymortality was 18.5%. Multivariate analysis identified the following predictors of CO-BSI-PA [adjusted OR (95% CI)]: male gender [1.89 (1.14–3.12)], haematological malignancy [2.45 (1.20–4.99)], obstructive uropathy [2.86 (1.13–3.02)], source of infection other than urinary tract, biliary tract or intra-abdominal [6.69 (4.10–10.92)] and healthcare-associated BSI [1.85 (1.13–3.02)]. Anindex predictive of CO-BSI-PA was developed; scores ≥ 3.5 showed a negative predictive value of 89% and an area under the receiver operator curve (ROC) of 0.66. Conclusions: We did not find a good predictive score of P. aeruginosa CO-BSI due to its relatively low incidence in the overall population. Our model includes variables that are easy to collect in real clinical practice and could be useful to detect patients with very low risk of P. aeruginosa CO-BSI.

Increases in methicillin-sensitive Staphylococcus aureus bloodstream infection incidence, 2016–2019

Background: Incidence of methicillin-sensitive Staphylococcus aureus (MSSA) bloodstream infections (BSIs) in the United States during 2012–2017 has been reported to have been stable for hospital-onset BSIs and to have increased 3.9% per year for community-onset BSIs. We sought to determine whether these trends continued in more recent years and whether there were further differences within subgroups of community-onset BSIs. Methods: We analyzed CDC Emerging Infections Program active, population- and laboratory-based surveillance data during 2016–2019 for MSSA BSIs from 8 counties in 5 states. BSI cases were defined as isolation of MSSA from blood in a surveillance area resident. Cases were considered hospital onset (HO) if culture was obtained &gt;3 days after hospital admission and healthcare-associated community-onset (HACO) if culture was obtained on or after day 3 of hospitalization and was associated with dialysis, hospitalization, surgery, or long-term care facility residence within 1 year prior or if a central venous catheter was present ≤2 days prior. Cases were otherwise considered community-associated (CA). Annual rates per 100,000 census population were calculated for each epidemiologic classification; rates of HACO cases among chronic dialysis patients per 100,000 dialysis patients were calculated using US Renal Data System data. Annual increases were modeled using negative binomial or Poisson regression and accounting for changes in the overall population age group, and sex. Descriptive analyses were performed. Results: Overall, 8,344 MSSA BSI cases were reported. From 2016–2019 total MSSA BSI rates increased from 23.9 per 100,000 to 28.5 per 100,000 (6.6% per year; P &lt; .01). MSSA BSI rates also increased significantly among all epidemiologic classes. HO cases increased from 2.5 per 100,000 to 3.2 per 100,000 (7.9% per year; P = .01). HACO cases increased from 12.7 per 100,000 to 14.7 per 100,000 (7.0% per year; P = .01). CA cases increased from 8.4 per 100,000 to 10.4 per 100,000 (6.7% per year; P &lt; .01) (Fig. 1). Significant increases in MSSA BSI rates were also observed for nondialysis HACO cases (9.3 per 100,000 to 11.1 per 100,000; 7.8% per year; P &lt; .01) but not dialysis HACO cases (1,823.2 per 100,000 to 1,857.4 per 100,000; 1.4% per year; P = .59). Healthcare risk factors for HACO cases were hospitalization in the previous year (82%), surgery (31%), dialysis (27%), and long-term care facility residence (19%). Conclusions: MSSA BSI rates increased from 2016–2019 overall, among all epidemiologic classes, and among nondialysis HACO cases. Efforts to prevent MSSA BSIs among individuals with healthcare risk factors, particularly those related to hospitalization, might have an impact on MSSA BSI rates.Funding: NoneDisclosures: None

Genomic epidemiology, antimicrobial resistance and virulence factors of Enterobacter cloacae complex causing potential community-onset bloodstream infections in a tertiary care hospital of Nepal.

ObjectivesCommunity-onset bloodstream infections (BSIs) caused by carbapenemase-producing Enterobacter cloacae complex (ECC) species are increasing internationally. This observation suggests that ECC are emerging pathogens, requiring for detailed understanding on their genomic epidemiology including transmission dynamics and antimicrobial resistance profiles.Patients and methodsWe performed WGS on 79 Enterobacter spp. isolated from the patients with clinically significant BSIs and admitted to emergency department of a major tertiary hospital in Nepal between April 2016 and October 2017.ResultsWe identified 5 species and 13 STs of ECC. Enterobacter xiangfangensis ST171, one of the globally emerging carbapenem resistant ECC clones with epidemic potential, was the most prevalent (42%). Phylogenetic analysis showed a large (>19 400 SNPs) core genome SNP distance across major STs, which was minimal (<30 SNPs) among the isolates of each prevalent ST, suggesting the relatively recent importation of major STs followed by local clonal expansions. Genomic evidence for resistance to all major antimicrobial classes except for colistin and macrolides was detected. A limited number of isolates also carried blaNDM-1 (n = 2) and blaOXA-48 (n = 1) carbapenemase genes. Virulence factors encoding siderophores (24%), T6SSD (25%) and fimbriae (54%) were detected.ConclusionsOur study highlighted that MDR ECC clones are important pathogens of BSIs in community. Though of low prevalence, carbapenem resistance observed in our ECC isolates raised concern about further community dissemination, underscoring the need for community surveillance to identify MDR ECC clones with epidemic potential.

From Pathophysiological Hypotheses to Case-Control Study Design: Resistance from Antibiotic Exposure in Community-Onset Infections.

Antimicrobial resistance is a global public health concern, at least partly due to the misuse of antibiotics. The increasing prevalence of antibiotic-resistant infections in the community has shifted at-risk populations into the general population. Numerous case–control studies attempt to better understand the link between antibiotic use and antibiotic-resistant community-onset infections. We review the designs of such studies, focusing on community-onset bloodstream and urinary tract infections. We highlight their methodological heterogeneity in the key points related to the antibiotic exposure, the population and design. We show the impact of this heterogeneity on study results, through the example of extended-spectrum β-lactamases producing Enterobacteriaceae. Finally, we emphasize the need for the greater standardization of such studies and discuss how the definition of a pathophysiological hypothesis specific to the bacteria–resistance pair studied is an important prerequisite to clarify the design of future studies.

A nationwide population-based study of Escherichia coli bloodstream infections: incidence, antimicrobial resistance and mortality

ObjectivesEscherichia coli is the leading cause of bloodstream infection (BSI). The incidence of E. coli BSI caused by antibiotic-resistant strains is increasing. We aimed to describe the nationwide incidence and resistance profile of E. coli BSI in Israel and its impact on mortality, to compare E. coli BSI mortality with all-cause mortality, and community-onset with hospital-onset E. coli BSIs. MethodsWe used mandatory BSI surveillance reports submitted by all Israeli hospitals to the Ministry of Health and the national death registry. All E. coli BSIs from 1 January 2018 to 31 December 31 2019 in patients aged 18 and over were included. ResultsA total of 11 113 E. coli BSIs occurred in 10 218 patients; 85% (9012/10 583) were community onset. Median age was 76 (IQR 65–85), and 57% (6304/11 113) of cases occurred in women. The annual incidence was 92.5 per 100 000 population. Antibiotic resistance was frequent and significantly more common in hospital-onset than in community-onset BSI; 65% (1021/1571) vs. 45% (4049/9012) were multidrug-resistant (MDR) (p < 0.001). The case fatality rate (CFR) was higher following hospital-onset BSI than community-onset: 23% (276/1214) vs. 12% (926/7620) at 14 days, 31% (378/1214) vs. 16% (1244/7620) at 30 days, and 55% (418/766) vs. 34% (1645/4903) at 1 year (p < 0.001 for all comparisons). The 1-year CFR was 47% (1258/2707) for MDR vs. 28% (928/3281) for non-MDR (p < 0.001). The annual mortality rate was 31.0 per 100 000 population, comprising 4.2% (31.0/734.8) of all causes of deaths. DiscussionE. coli BSI carries a high burden, with a large proportion of MDR isolates, which are associated with increased incidence and CFR.

Analysis of Prognostic Risk Factors of Bloodstream Infections in Beijing Communities: A Retrospective Study from 2015 to 2019.

ObjectiveThis study intends to investigate the prognostic risk factors of bloodstream infection in Beijing.MethodsThis study is a clinical retrospective study. Four hundred forty-six patients with community-onset bloodstream infections (COBSI), admitted to the emergency department and inpatient department of Beijing Jishuitan Hospital from January 1, 2015, to December 31, 2019, were selected as the main research objects. According to whether the patient survives for 100 days or not, 363 cases were in the survival group, and 83 cases were in the death group. By analyzing the clinical data of the two groups of patients, the epidemiology, clinical characteristics, bacterial resistance, and risk factors affecting the prognosis of the patients were analyzed.ResultsA total of 446 pathogenic bacteria were isolated in this study, including 324 Gram-negative (G-) bacteria (72.6%), 121 Gram-positive (G+) bacteria (27.1%). The results of the study showed that there were significant differences in MDR, initial antibiotic use, solid tumor, CKD, septic shock, acute liver injury, AKI, central venous catheter, urinary catheter, blood replacement therapy, invasive operation, and use of three or more antibiotics between the two groups (p<0.05). The multiple logistic regression analysis showed that solid tumors (OR=3.339, 95% CI: (1.441, 7.734), p=0.005), combined septic shock (OR=20.729, 95% CI: (10.235, 41.982), p<0.001), indwelling catheters (OR=3.556, 95% CI: (1.538, 8.222), p=0.003) and continuous venovenous hemofiltration (CVVH, OR=19.548, 95% CI: (8.724, 35.641), p=0.003) are independent risk factors affecting the prognosis of COBSI patients. Appropriate initial antibiotic therapy is a protective factor affecting the prognosis of COBSI patients.ConclusionSolid tumors, combined septic shock, indwelling catheters, CVVH are independent risk factors affecting the prognosis of COBSI patients.

Clinical Characteristics of Patients and Whole Genome Sequencing-Based Surveillance of Escherichia coli Community-Onset Bloodstream Infections at a Non-tertiary Hospital in CHINA.

Background: Escherichia coli is the most common pathogens in patients with community-onset blood stream infections (COBSI). Knowledge of the epidemiology of this disease is crucial to improve allocation of health resources, formulate isolation strategies that prevent transmission, and guide empirical antibiotic therapy.Methods: This retrospective observational study examined patients with E. coli COBSI (EC-COBSI) at a non-tertiary hospital in China. Whole-genome sequencing and analysis of the isolates was performed. The relationships of clinical variables with antimicrobial resistance and the genetic background of the isolates were examined.Results: There were 148 isolates in patients with EC-COBSI. All isolates were susceptible to ceftazidime/avibactam, carbapenems, and tigecycline; 35.1% were positive for extended spectrum β-lactamase (ESBL+); and blaCTX–M–14 was the most common ESBL gene. Patients with ESBL- isolates were more likely to receive appropriate empiric treatment than those with ESBL+ isolates (61.5% vs. 91.4%, p < 0.001), but these two groups had similar mortality rates. The overall 30-day mortality rate was 9.5%. Phylogenetic analysis showed that the isolates were diverse, and that the main sequence types (STs) were ST95, ST131, and ST69. Intra-abdominal infection was the primary source of disease, and isolates from these patients had lower frequencies of virulence genes.Conclusion: The mortality rate of patients with EC-COBSI was unrelated to ESBL status of the isolates. Most isolates had low resistance to most of the tested antimicrobial agents. The isolates were diverse, and multiple strains were related. Prevention and control of EC-COBSI should target prevention of patient colonization and the living environment.

Risk Factors for Extended-Spectrum-β-Lactamase-Producing Escherichia coli in Community-Onset Bloodstream Infection: Impact on Long-Term Care Hospitals in Korea.

BackgroundThe prevalence of extended-spectrum β-lactamase-producing Escherichia coli (ESBL-EC) in the community has increased worldwide due to multifactorial reasons. ESBL-EC bloodstream infection (BSI) complicates the decision for proper antimicrobial administration. In this multicenter study, we investigated the prevalence, risk factors, and molecular background of community-onset (CO) ESBL-EC BSI.MethodsWe included data for all episodes of ESBL-EC BSI of community origin from May 2016 to April 2017 obtained from the Korean national antimicrobial resistance surveillance system, which comprises six sentinel hospitals. Data, including previous history of admission and use of antimicrobials and medical devices before BSI, were collected, along with microbiological analysis results.ResultsAmong 1,189 patients with CO BSI caused by E. coli, 316 (27%) were identified as ESBL producers. History of admission, especially to a long-term care hospital (LTCH), and previous use of β-lactams/β-lactamase inhibitors, carbapenem, lincosamide, aminoglycoside, and extended-spectrum cephalosporin were independent risk factors for CO ESBL-EC BSI; admission to an LTCH showed the highest odds ratio (3.8, 95% confidence interval 2.3-6.1). The most common genotype was CTX-M-15 (N=131, 41%), followed by CTX-M-14 (N=86, 27%). ST131 was the most common sequence type among ESBL-EC groups (57%).ConclusionsIn Korea, 27% of CO E. coli BSI were caused by ESBL producers. From perspectives of empirical treatment and infection control, history of admission to an LTCH and antimicrobial use should be noted.