Previous Bloodstream Infection Research Articles

Derivation and External Validation of the Ottawa Bloodstream Infection Model for Acutely Ill Adults.

Knowing the probability that patients have a bloodstream infection (BSI) could influence the ordering of blood cultures and interpretation of their preliminary results. Many previous BSI probability models have limited applicability and accuracy. This study used currently recommended modeling techniques and a large sample to derive and validate the Ottawa BSI Model. At a tertiary care teaching hospital, we retrieved a random sample of 4180 adults having blood cultures in our emergency department or during the initial 48h of the encounter. Variable selection was based on clinical experience and a systematic review of previous model performance. Model performance was measured in a temporal external validation group of 4680 patients. A total of 327 derivation patients had a BSI (8.0%). BSI risk increased with increased number of culture sets (2 sets: adjusted odds ratio [aOR] 1.52 [1.10-2.11]; 3 sets: 1.99 [0.86-4.58]); with indwelling catheter (aOR 2.07 [1.34-3.20); with increasing temperature, heart rate, and neutrophil-lymphocyte ratio; and with decreasing systolic blood pressure, platelet count, urea-creatinine ratio, and estimated glomerular filtration rate. In the temporal external validation group, model discrimination was good (c-statistic 0.71 [0.69-0.74]) and calibration was very good (integrated calibration index .016 [.010-.024]). Exclusion of validation patients with acute SARS-CoV-2 infection improved discrimination slightly (c-statistic 0.73 [0.69-0.76]). The Ottawa BSI Model uses commonly available data to return an expected BSI probability for acutely ill patients. However, it cannot exclude BSI and its complexity requires computational assistance to use.

Population-Based Incidence and Characteristics of Adult Escherichia coli Bloodstream Infection in Queensland, Australia, From 2000 to 2019.

There is increasing morbidity and mortality attributed to escalating incidence of Escherichia coli bloodstream infection (BSI). The epidemiology of E. coli BSI is dynamic and differs across populations. This study aimed to describe this epidemiology in Queensland, Australia. Incident E. coli BSIs (new or recurring ≥30 days from previous BSI) in adult (≥15 years) Queenslanders were identified from 2000 to 2019 using Queensland Health databases. Incidence rates, crude and standardized by age and gender, were calculated. Negative binomial regressions were performed to determine predictors of E. coli BSI incidence. From 2000 to 2019, 30 350 E. coli BSIs in 27 793 patients were detected; the standardized incidence rate almost doubled from 34.1 to 65.9 cases per 100 000 residents. Predictors of higher incidence rate were older age (≥65 years), comorbidity, and community-onset infection. Despite holding these factors constant, the incidence rate was estimated to increase 4% (adjusted incidence rate ratio [IRR], 1.04; 95% CI, 1.03-1.04) annually over the study period. Approximately 4.2% of E. coli isolates produced extended-spectrum beta-lactamase (ESBL-Ec), with most (95%) detected after 2010. The incidence rate of ESBL-Ec increased 25% (IRR, 1.25%; 95% CI, 1.2-1.3) annually, significantly faster than that of non-producers. Amikacin and carbapenems remain effective in vitro against ESBL-Ec BSI in Queensland. The rise in E. coli BSIs is driven both by a higher infection rate and shifting epidemiology toward community-onset infections. These are likely attributed to an aging Australian population with increasing chronic comorbidity. The rapid expansion of ESBL-Ec in recent years is concerning and should be acknowledged for its implication in the community.

Recurrent bloodstream infections after allogeneic hematopoietic cell transplantation

ABSTRACT Background Although colonization is an established risk factor for bloodstream infection (BSI) due to identical strain, prior infection with resistant bacteria should also be considered during the management of febrile neutropenia. This study aimed to analyze the rate and etiology of recurrent BSI in allogeneic hematopoietic cell transplant (allo-HCT) recipients to determine its potential impact on decision-making. Materials and methods The retrospective study included 284 allo-HCT recipients. Recurrent BSI was defined as a new BSI episode occurring in a period of more than 72 hours after antibiotic withdrawal. Results Overall, 104 patients (36.6%) developed at least one BSI, and 23 of them (22.1%) experienced recurrent BSI episodes (n = 30). Median time to recurrent BSI was 41 days (range 5–526 days). Recurrent BSI was associated with second allo-HCT (p < 0.0001), primary (p = 0.021), and secondary graft failure (p = 0.024). Carbapenem-resistant gram-negative bacteria were more common during recurrent BSI episodes (23.7% vs. 6.0%; p = 0.003). In only 17.5% patients experiencing recurrent BSI episode and in only 3.9% of patients with at least one BSI episode phenotypically identical recurring pathogen was isolated. Conclusions In view of low rate of recurrent BSI due to identical pathogen, empirical antimicrobial therapy should not be based on data on previous BSI episodes.

Incidence, microbiological aspects and associated risk factors of catheter-related bloodstream infections in adults on chronic haemodialysis at a tertiary hospital in Uganda

The high burden of infectious complications among patients receiving haemodialysis (HD) via central venous catheters increases morbidity and mortality. This study determined the incidence of catheter-related bloodstream infections (CRBSIs), microbiological profile of causative organisms, and associated predictors in patients on chronic HD. A prospective single-centre cohort study of 121 adult patients with end-stage kidney disease was conducted from October 2019 to March 2020. Antibiotic susceptibility was determined by the Kirby-Bauer disk diffusion method. Cox proportional hazards model was used to determine predictors of CRBSI. The mean age was 50 (standard deviation 14.9) years and the median duration of follow-up was 69 (interquartile range 23-124) days. At least one CRBSI was recorded for 41% of patients, at a rate of 5.2 infections per 1000 patient-days. Causative organisms were predominantly Gram-negative bacteria (60.3%), and 36.5% of all isolates were multi-drug resistant. Anaemia [hazard ratio (HR) 5.44, P=0.019, 95% confidence interval (CI) 1.32-22.48] and previous bloodstream infection [HR 2.47, P=0.028, 95% CI 1.10-5.54] were predictors of CRBSI. The high incidence of CRBSI in patients on chronic HD with predominance of Gram-negative bacteria means that catheter care bundles should include Gram-negative coverage.

Peripherally inserted central catheter-related bloodstream infections in patients with hematological malignancies: A retrospective 7-years single-center study

ObjectivesWe sought to investigate the nature and incidence of bloodstream infection complications and to identify the risk factors of central catheter-related bloodstream infections (CRBSI). MethodsDuring the study period, 291 consecutive patients with hematological malignancies who underwent PICC placement were retrospectively enrolled. We analyzed the covariates that were specified a priori for their association with CRBSI through multivariate Cox proportional hazards regression models. The association between each predictor and the related outcome was expressed using hazard ratios (HRs) with corresponding 95% confidence intervals (CIs). ResultsOf 391 peripherally inserted central catheter (PICCs) were inserted in 291 patients for a total of 63,714 catheter days during 7 years, with an infection rate of 0.71/1,000 catheter days. Among the patients with hematological malignancies, those with acute leukemia were prone to CRBSI. Having previous bloodstream infection (BSI) (HR 18.139; 95% CI, 8.19-40.174; P < .0001), the number of PICCs insertions (HR 4.695; 95% CI, 1.842-11.967; P = .001) (twice), (HR 6.794; 95% CI, 1.909-24.181; P = .003) (≥3 times) were significantly associated with CRBSI. Not accompanied by chronic comorbidities (HR 0.34; 95% CI, 0.131-0.887; P = .028) and longer duration of PICC use (days) (HR 0.997; 95% CI, 0.994-0.999; P = .008) might be protective factors preventing CRBSI. ConclusionsOur finding suggests that previous BSI and a higher number of PICC insertions are associated with an increased risk of CRBSI. A lack of chronic comorbidities may help prevent CRBSI.

Risk factors for HTLV-1, acute kidney injury, and urinary tract infection amongaboriginal adults with end stage kidney disease in central Australia.

Central Australia is a human T-cell leukemia virus type 1c (HTLV-1c) endemic region andhas the highest incidence of chronic kidney disease (CKD) in Australia. The factors associated with HTLV-1 seropositivity among Aboriginal Australian adults with CKD receiving hemodialysis (HD) were determined. A retrospective observational study of Aboriginal adults (≥ 18 years) who were receiving regular HD at the two main dialysis units in Alice Springs, December 1, 2010 to December 31, 2015. Demographic and clinical data before commencing HD were extracted from hospital records from the first presentation to Alice Springs Hospital (ASH) to HD commencement and associations were determined using logistic regression. Among 373 patients receiving HD, 133 (35.9%) were HTLV-1 infected. Identifiable factors associated with HTLV-1 status included increasing age, male gender, and diabetesbefore HD. The odds of diabetes mellitus were significantly higher among patients with HTLV-1 (adjusted odds ratio [aOR]: 2.76, 95% confidence interval [CI]: 1.19, 6.39; p = 0.017). More than one-fifth of participants had an acute kidney injury, the risk of which was increased among those with a previous blood stream infection (aOR: 3.02, 95% CI: 1.71, 5.34, p < 0.001). Men with a high HTLV-1 proviral load (≥500 copies per 105 peripheral blood leukocytes) had an increased risk of urinary tract infection (UTI)before HD (aOR: 5.15, 95% CI: 1.62, 16.40; p = 0.006). A strong association between HTLV-1 and diabetes, and an increased risk of UTI among men with a high HTLV-1 PVL, suggest that interactions between HTLV-1 infection and conventional risk factors may increase the risk for CKD in this population.

Incidence, risk factors, and outcome of blood stream infections during the first 100 days post-pediatric allogeneic and autologous hematopoietic stem cell transplantations.

Bloodstream infections (BSI) are a frequently observed complication after hematopoietic stem cell transplant (HSCT). Retrospective analysis of clinical and microbiological data during the first 100days from 302 consecutive pediatric patients who underwent HSCT for a malignant disease at our institute between January 2013 and June 2017. A total of 164 patients underwent autologous and 138 allogeneic HSCT. The overall incidence of BSI was 37% with 92% of infectious episodes occurring during the pre-engraftment phase. Gram-positive bacteria (GPB) accounted for 54.6% of the isolated pathogens, gram-negative bacteria (GNB) for 43.9%, and fungi for 1.4%. Coagulase-negative staphylococci and Escherichia coli were the most commonly isolated GPB and GNB, respectively. Forty-five percent of GNB were extended-spectrum beta-lactamase producers and 21% were multidrug-resistant organisms. Fluoroquinolone resistance was 92% and 68%, among GPB and GNB, respectively. Risk factors for BSI in univariate analysis were allogeneic HSCT, delayed time to engraftment more than 12days, previous BSI before HSCT, and alternative donor. In multivariate analysis, only HSCT type (allogeneic vs autologous P=.03) and previous BSI within 6months before HSCT (P=.016) were significant. Overall survival at day 100 was 98% and did not differ significantly between patients with and without BSI (P=.76). BSI is common in children undergoing HSCT for malignant diseases. Allogeneic HSCT recipients and previous BSI within 6months before HSCT are associated with increased risk of post-transplant BSI. With current supportive measures, BSI does not seem to confer an increased risk for 100-day mortality.

Previous bloodstream infections due to other pathogens as predictors of carbapenem-resistant Klebsiella pneumoniae bacteraemia in colonized patients: results from a retrospective multicentre study.

the purpose of this retrospective multicenter study was to assess whether the risk of developing bloodstream infections (BSI) due to carbapenem-resistant Klebsiella pneumoniae (CRKP) in colonized patients is influenced by the occurrence of BSI due to other pathogens. from January 2012 to March 2014, all patients with at least one rectal swab positive for CRKP and at least 30days of previous hospital stay were included in the study. The primary outcome measure was CRKP BSI, defined as a time-to-event endpoint. The role of potential predictors was evaluated through univariable and multivariable Cox regression analyses, considering previous BSI as a time-dependent variable. during the study period, 353 patients met the inclusion criteria. Thirty-seven developed a CRKP BSI (11%). A higher incidence of CRKP BSI was observed in presence rather than in absence of previous BSI. In the final multivariable model of risk factors for CRKP BSI, multisite colonization (hazard ratio [HR] 13.73, 95% confidence intervals [CI] 3.29-57.32, p < 0.001), ICU stay (HR 3.14, 95% CI 1.19-8.31, p =0.021), and previous BSI (p =0.026, with the overall effect being mainly due to Enterococcus spp. BSI vs absence of BSI, HR 6.62, 95% CI 2.11-20.79) were associated with the development of CRKP BSI, while an inverse association was observed for age (HR 0.98, 95% CI 0.95-1.00, p =0.027). previous BSI due to other pathogens were associated with an increased risk of CRKP BSI that was independent of other factors in colonized patients with prolonged hospital exposure.

Non-communicable diseases, infection and survival in a retrospective cohort of Indigenous and non-Indigenous adults in central Australia

ObjectivesWe hypothesise that rising prevalence rates of non-communicable diseases (NCDs) increase infection risk and worsen outcomes among socially disadvantaged Indigenous Australians undergoing a rapid epidemiological transition.DesignAvailable pathology, imaging and discharge...

Healthcare workers and prevention of hepatitis C virus transmission: exploring knowledge, attitudes and evidence-based practices in hemodialysis units in Italy.

BackgroundEvidence exists regarding the full prevention of HCV transmission to hemodialysis patients by implementing universal precaution. However, little information is available regarding the frequency with which hospitals have adopted evidence-based practices for preventing HCV infection among hemodialysis patients. A cross-sectional survey has been conducted among nurses in Calabria region (Italy) in order to acquire information about the level of knowledge, the attitudes and the frequencies of evidence-based practices that prevent hospital transmission of HCV.MethodsAll 37 hemodialysis units (HDU) of Calabria were included in the study and all nurses were invited to participate in the study and to fill in a self-administered questionnaire.Results90% of the nurses working in HDU participated in the study. Correct answers about HCV pattern of transmission ranged from 73.7% to 99.3% and were significantly higher in respondents who knew that isolation of HCV-infected patients is not recommended and among those who knew that previous bloodstream infections should be included in medical record and among nurses with fewer years of practice. Most correctly thought that evidence-based infection control measures provide adequate protection against transmission of bloodborne pathogens among healthcare workers. Positive attitude was significantly higher among more knowledgeable nurses. Self-reporting of appropriate handwashing procedures were significantly more likely in nurses who were aware that transmission of bloodborne pathogens among healthcare workers may be prevented through adoption of evidence-based practices and with a correct knowledge about HCV transmission patterns.ConclusionsBehavior changes should be aimed at abandoning outdated practices and adopting and maintaining evidence-based practices. Initiatives focused at enabling and reinforcing adherence to effective prevention practices among nurses in HDU are strongly needed.

Multidrug-resistant Pseudomonas aeruginosa bloodstream infections: risk factors and mortality

We retrospectively studied patients diagnosed with P. aeruginosa bloodstream infections (BSIs) in two Italian university hospitals. Risk factors for the isolation of multidrug-resistant (MDR) or non-MDR P. aeruginosa in blood cultures were identified by a case-case-control study, and a cohort study evaluated the clinical outcomes of such infections. We identified 106 patients with P. aeruginosa BSI over the 2-year study period; 40 cases with MDR P. aeruginosa and 66 cases with non-MDR P. aeruginosa were compared to 212 controls. Independent risk factors for the isolation of MDR P. aeruginosa were: presence of central venous catheter (CVC), previous antibiotic therapy, and corticosteroid therapy. Independent risk factors for non-MDR P. aeruginosa were: previous BSI, neutrophil count <500/mm3, urinary catheterization, and presence of CVC. The 21-day mortality rate of all patients was 33·9%. The variables independently associated with 21-day mortality were presentation with septic shock, infection due to MDR P. aeruginosa, and inadequate initial antimicrobial therapy.

Severe worsening of parkinsonism in Lewy body dementia due to donepezil

<h3>Objectives</h3> We hypothesise that rising prevalence rates of non-communicable diseases (NCDs) increase infection risk and worsen outcomes among socially disadvantaged Indigenous Australians undergoing a rapid epidemiological transition. <h3>Design</h3> Available pathology, imaging and discharge morbidity codes were retrospectively reviewed for a period of 5 years prior to admission with a bloodstream infection (BSI), 1 January 2003 to 30 June 2007. <h3>Participants</h3> 558 Indigenous and 55 non-Indigenous community residents of central Australia. <h3>Outcome measures</h3> The effects of NCDs on risk of infection and death were determined after stratifying by ethnicity. <h3>Results</h3> The mean annual BSI incidence rates were far higher among Indigenous residents (Indigenous, 937/100 000; non-Indigenous, 64/100 000 person-years; IRR=14.6; 95% CI 14.61 to 14.65, p&lt;0.001). Indigenous patients were also more likely to have previous bacterial infections (68.7% vs 34.6%; respectively, p&lt;0.001), diabetes (44.3% vs 20%; p&lt;0.001), harmful alcohol consumption (37% vs 12.7%; p&lt;0.001) and other communicable diseases (human T-lymphotropic virus type 1, 45.2%; strongyloidiasis, 36.1%; hepatitis B virus, 12.9%). Among Indigenous patients, diabetes increased the odds of current <i>Staphylococcus aureus</i> BSI (OR=1.6, 95% CI 1.0 to 2.5) and prior skin infections (adjusted OR=2.1, 95% CI 1.4 to 3.3). Harmful alcohol consumption increased the odds of current <i>Streptococcus pneumoniae</i> BSI (OR=1.57, 95% CI 1.02 to 2.40) and of previous BSI (OR=1.7, 95% CI 1.1 to 2.5), skin infection (OR=1.7, 95% CI 1.1 to 2.6) or pneumonia (OR=4.3, 95% CI 2.8 to 6.7). Twenty-six per cent of Indigenous patients died at a mean (SD) age of 47±15 years. Complications of diabetes and harmful alcohol consumption predicted 28-day mortality (non-rheumatic heart disease, HR=2.9; 95% CI 1.4 to 6.2; chronic renal failure, HR=2.6, 95%CI 1.0 to 6.5; chronic liver disease, HR=3.3, 95% CI 1.6 to 6.7). <h3>Conclusions</h3> In a socially disadvantaged population undergoing a rapid epidemiological transition, NCDs are associated with an increased risk of infection and BSI-related mortality. Complex interactions between communicable diseases and NCDs demand an integrated approach to management, which must include the empowerment of affected populations to promote behavioural change.

Incidence of bloodstream infection in multicenter inception cohorts of hemodialysis patients

Objective To assess incidence of and identify risk factors for bloodstream infection in patients starting hemodialysis or starting a new means of vascular access for hemodialysis. Method Two cohorts of patients, 1 initiating hemodialysis (new patients) and a 1:1 matching group of patients continuing hemodialysis but starting a new vascular access (continuing patients), were enrolled from 9 Canadian hemodialysis units and followed for 6 months. Bloodstream infection was defined using established criteria. A nested case-control study was carried out, using as cases those cohort patients diagnosed with infection. Each case was matched with a control having the same means of access and new or continuing status. Results A total of 527 patients (258 new, 269 continuing), were recruited and underwent 31,268 hemodialysis procedures during this 6-month follow-up. There were 96 bloodstream infections in 93 patients (11.97/10,000 days, 28.81/10,000 hemodialysis procedures), yielding a relative risk of infection of 3.33 (95% CI, 2.12-5.24) for patients with a previous bloodstream infection and 1.56 (95% CI, 1.02-2.38) for patients continuing hemodialysis by a new means of access. Survival analysis revealed that compared to arteriovenous fistula vascular access, the relative risk of bloodstream infection in patients was 1.47 (95% CI, 0.36-5.96) for arteriovenous grafts, 8.49 (95% CI, 3.03-23.78) for cuffed central venous catheters, and 9.87 (95% CI, 3.46-28.20) for uncuffed central venous catheters. The regression model of the case-control study identified earlier bloodstream infection (OR, 6.58), poor patient hygiene (OR, 3.48), and superficial access-site infection (OR, 4.36) as additional risk factors. Conclusion During the first 6 months there is a high rate of bloodstream infection in patients starting hemodialysis either for the first time or by a new means of vascular access. Previous hemodialysis bloodstream infection and continuing hemodialysis by a new means of vascular access are markers for an increased risk of infection, as is poor patient hygiene. Central venous catheter vascular access, whether cuffed or uncuffed, has a much higher infection risk. In this study, there was no difference in infection rate between cuffed and uncuffed central catheters.

Incidence of bloodstream infection in multicenter inception cohorts of hemodialysis patients

Objective To assess incidence of and identify risk factors for bloodstream infection in patients starting hemodialysis or starting a new means of vascular access for hemodialysis. Method Two cohorts of patients, 1 initiating hemodialysis (new patients) and a 1:1 matching group of patients continuing hemodialysis but starting a new vascular access (continuing patients), were enrolled from 9 Canadian hemodialysis units and followed for 6 months. Bloodstream infection was defined using established criteria. A nested case-control study was carried out, using as cases those cohort patients diagnosed with infection. Each case was matched with a control having the same means of access and new or continuing status. Results A total of 527 patients (258 new, 269 continuing), were recruited and underwent 31,268 hemodialysis procedures during this 6-month follow-up. There were 96 bloodstream infections in 93 patients (11.97/10,000 days, 28.81/10,000 hemodialysis procedures), yielding a relative risk of infection of 3.33 (95% CI, 2.12-5.24) for patients with a previous bloodstream infection and 1.56 (95% CI, 1.02-2.38) for patients continuing hemodialysis by a new means of access. Survival analysis revealed that compared to arteriovenous fistula vascular access, the relative risk of bloodstream infection in patients was 1.47 (95% CI, 0.36-5.96) for arteriovenous grafts, 8.49 (95% CI, 3.03-23.78) for cuffed central venous catheters, and 9.87 (95% CI, 3.46-28.20) for uncuffed central venous catheters. The regression model of the case-control study identified earlier bloodstream infection (OR, 6.58), poor patient hygiene (OR, 3.48), and superficial access-site infection (OR, 4.36) as additional risk factors. Conclusion During the first 6 months there is a high rate of bloodstream infection in patients starting hemodialysis either for the first time or by a new means of vascular access. Previous hemodialysis bloodstream infection and continuing hemodialysis by a new means of vascular access are markers for an increased risk of infection, as is poor patient hygiene. Central venous catheter vascular access, whether cuffed or uncuffed, has a much higher infection risk. In this study, there was no difference in infection rate between cuffed and uncuffed central catheters.

Current Literature: Prospective Evaluation of Risk Factors for Bloodstream Infection in Patients Receiving Home Infusion Therapy

Background: Intravenous therapy in the outpatient and home settings is commonplace for many diseases and nutritional disorders. Few data are available on the rate of and risk factors for bloodstream infection among patients receiving such therapy. Objective: To determine rates of and risk factors for bloodstream infection among patients receiving home infusion therapy. Design: Prospective, observational cohort study. Setting: Cleveland, Ohio, and Toronto, Ontario, Canada. Patients: Patients receiving home infusion therapy through a central or midline catheter. Measurements: Primary laboratory‐confirmed bloodstream infection. Results: Among 827 patients (988 catheters), the most common diagnoses were infections other than HIV (67%), cancer (24%), nutritional and digestive disease (17%), heart disease (14%), receipt of bone marrow or solid organ transplants (11%), and HIV infection (7%). Sixty‐nine bloodstream infections occurred during 69,532 catheter days (0.99 infections per 1000 days). In a Cox regression model with time‐dependent covariates, independent risk factors for bloodstream infection were recent receipt of a bone marrow transplant (hazard ratio, 5.8 [95% CI, 3.0 to 11.3]), receipt of total parenteral nutrition (hazard ratio, 4.1 [CI, 2.3 to 7.2]), receipt of therapy outside the home (for example, in an outpatient clinic or physician's office) (hazard ratio, 3.6 [CI, 2.2 to 5.9]), use of a multilumen catheter (hazard ratio, 2.8 [CI, 1.7 to 4.7]), and previous bloodstream infection (hazard ratio, 2.5 [CI, 1.5 to 4.2]). Rates of bloodstream infection per 1000 catheter‐days varied from 0.16 for patients with none of these 5 risk factors to 6.77 for patients with 3 or more risk factors. Centrally inserted venous catheters were associated with a higher risk than implanted ports were, but the difference was not statistically significant. Conclusion: Bloodstream infections seem to be infrequent among outpatients receiving infusions through central and midline catheters. However, the rate of infection increases with bone marrow transplantation, parenteral nutrition, infusion therapy in a hospital clinic or physician's office, and use of multilumen catheters. Compared with implanted ports or peripherally inserted catheters, centrally inserted venous catheters may confer greater risk for bloodstream infection. (Ann Intern Med 131:340–347, 1999)

Prospective evaluation of risk factors for bloodstream infection in patients receiving home infusion therapy.

Intravenous therapy in the outpatient and home settings is commonplace for many diseases and nutritional disorders. Few data are available on the rate of and risk factors for bloodstream infection among patients receiving such therapy. To determine rates of and risk factors for bloodstream infection among patients receiving home infusion therapy. Prospective, observational cohort study. Cleveland, Ohio, and Toronto, Ontario, Canada. Patients receiving home infusion therapy through a central or midline catheter. Primary laboratory-confirmed bloodstream infection. Among 827 patients (988 catheters), the most common diagnoses were infections other than HIV (67%), cancer (24%), nutritional and digestive disease (17%), heart disease (14%), receipt of bone marrow or solid organ transplants (11%), and HIV infection (7%). Sixty-nine bloodstream infections occurred during 69,532 catheter-days (0.99 infections per 1000 days). In a Cox regression model with time-dependent covariates, independent risk factors for bloodstream infection were recent receipt of a bone marrow transplant (hazard ratio, 5.8 [95% CI, 3.0 to 11.3]), receipt of total parenteral nutrition (hazard ratio, 4.1 [CI, 2.3 to 7.2]), receipt of therapy outside the home (for example, in an outpatient clinic or physician's office) (hazard ratio, 3.6 [CI, 2.2 to 5.9]), use of a multilumen catheter (hazard ratio, 2.8 [CI, 1.7 to 4.7]), and previous bloodstream infection (hazard ratio, 2.5 [CI, 1.5 to 4.2]). Rates of bloodstream infection per 1000 catheter-days varied from 0.16 for patients with none of these 5 risk factors to 6.77 for patients with 3 or more risk factors. Centrally inserted venous catheters were associated with a higher risk than implanted ports were, but the difference was not statistically significant. Bloodstream infections seem to be infrequent among outpatients receiving infusions through central and midline catheters. However, the rate of infection increases with bone marrow transplantation, parenteral nutrition, infusion therapy in a hospital clinic or physician's office, and use of multilumen catheters. Compared with implanted ports or peripherally inserted catheters, centrally inserted venous catheters may confer greater risk for bloodstream infection.