Bloodstream Infections in a Community Hospital: A 25-Year Follow-Up

Antibiotic resistance of blood cultures in regional and tertiary hospital settings of Tyrol, Austria (2006-2015): Impacts & trends

Blood stream infections rank among the top seven causes of death of the general population. The aim of our study was to better understand the epidemiology of BSI in order to improve diagnostics and patient outcome. We used retrospective aggregated laboratory data of blood samples received from all public hospitals in Tyrol, Austria between 2006 and 2015. Microorganisms were categorized into obligatory, facultative, unusual pathogens and contaminants. The distribution, the cumulative incidence and antimicrobial susceptibility patterns were compared between the tertiary (TH) and regional peripheral hospitals (PH). Among 256,364 blood samples, 76.1% were from the TH The incidence of obligatory pathogens was 1.7 fold, and up to 3 times higher for facultative, unusual pathogens and contaminants in the TH and increased mainly due to an increase of E.coli, which was the most common isolated pathogen (n = 2,869), followed by Staphylococcus aureus (n = 1,439), Enterococcus sp. (n = 953) and Klebsiella sp. (n = 816). The distribution of obligatory pathogens differed between the hospital settings: In the TH Enterococcus sp. accounted for 40.8% and E.coli for 70.4%, respectively, whereas in the PH for 25.4% (p<0.0001) and 57.8%, respectively (p<0.0001) Antibiotic resistance of Gram negative bacteria and Staphylococcus aureus did not change during the observation period. Carbapenem resistance of Klebsiella sp. and vancomycin and linezolid resistance of Enterococcus faecium showed a non-significant increase since 2010 in the TH setting. We concluded that the incidence of BSI in TH was higher compared to PH. We observed higher contamination rates in the TH. We could not interpret the data of coagulase negative staphylococci due to lack of clinical data. We strongly recommend enhancement of training on blood culture sampling to decrease the rate of contamination. Due to differences in pathogen distribution and antimicrobial resistance between different hospital settings we recommend separate treatment guidelines for BSI by hospital setting.

A ten-year review of healthcare-associated bloodstream infections from forty hospitals in Québec, Canada

OBJECTIVE

Healthcare-associated bloodstream infections (HABSI) are a significant cause of morbidity and mortality worldwide. In Québec, Canada, HABSI arising from acute-care hospitals have been monitored since April 2007 through the Surveillance des bactériémies nosocomiales panhospitalières (BACTOT) program, but this is the first detailed description of HABSI epidemiology.

METHODS

This retrospective, descriptive study was conducted using BACTOT surveillance data from hospitals that participated continuously between April 1, 2007, and March 31, 2017. HABSI cases and rates were stratified by hospital type and/or infection source. Temporal trends of rates were analyzed by fitting generalized estimating equation Poisson models, and they were stratified by infection source.

RESULTS

For 40 hospitals, 13,024 HABSI cases and 23,313,959 patient days were recorded, for an overall rate of 5.59 per 10,000 patient days (95% CI, 5.54-5.63). The most common infection sources were catheter-associated BSIs (23.0%), BSIs secondary to a urinary focus (21.5%), and non-catheter-associated primary BSIs (18.1%). Teaching hospitals and nonteaching hospitals with ICUs often had rates higher than nonteaching hospitals without ICUs. Annual HABSI rates did not exhibit statistically significant changes from year to year. Non-catheter-associated primary BSIs were the only HABSI type that exhibited a sustained change across the 10 years, increasing from 0.69 per 10,000 patient days (95% CI, 0.59-0.80) in 2007-2008 to 1.42 per 10,000 patient days (95% CI, 1.27-1.58) in 2016-2017.

CONCLUSIONS

Despite ongoing surveillance, overall HABSI rates have not decreased. The effect of BACTOT participation should be more closely investigated, and targeted interventions along alternative surveillance modalities should be considered, prioritizing high-burden and potentially preventable BSI types.

Bloodstream infections in community hospitals in the 21st century: a multicenter cohort study

Background

While the majority of healthcare in the US is provided in community hospitals, the epidemiology and treatment of bloodstream infections in this setting is unknown.

Methods and Findings

We undertook this multicenter, retrospective cohort study to 1) describe the epidemiology of bloodstream infections (BSI) in a network of community hospitals and 2) determine risk factors for inappropriate therapy for bloodstream infections in community hospitals. 1,470 patients were identified as having a BSI in 9 community hospitals in the southeastern US from 2003 through 2006. The majority of BSIs were community-onset, healthcare associated (n = 823, 56%); 432 (29%) patients had community-acquired BSI, and 215 (15%) had hospital-onset, healthcare-associated BSI. BSIs due to multidrug-resistant pathogens occurred in 340 patients (23%). Overall, the three most common pathogens were S. aureus (n = 428, 28%), E. coli (n = 359, 24%), coagulase-negative Staphylococci (n = 148, 10%), though type of infecting organism varied by location of acquisition (e.g., community-acquired). Inappropriate empiric antimicrobial therapy was given to 542 (38%) patients. Proportions of inappropriate therapy varied by hospital (median = 33%, range 21–71%). Multivariate logistic regression identified the following factors independently associated with failure to receive appropriate empiric antimicrobial therapy: hospital where the patient received care (p<0.001), assistance with ≥3 ADLs (p = 0.005), Charlson score (p = 0.05), community-onset, healthcare-associated infection (p = 0.01), and hospital-onset, healthcare-associated infection (p = 0.02). Important interaction was observed between Charlson score and location of acquisition.

Conclusions

Our large, multicenter study provides the most complete picture of BSIs in community hospitals in the US to date. The epidemiology of BSIs in community hospitals has changed: community-onset, healthcare-associated BSI is most common, S. aureus is the most common cause, and 1 of 3 patients with a BSI receives inappropriate empiric antimicrobial therapy. Our data suggest that appropriateness of empiric antimicrobial therapy is an important and needed performance metric for physicians and hospital stewardship programs in community hospitals.

Species-driven interpretation guidelines in case of a single-sampling strategy for blood culture

The purpose of this paper is to define guidelines to interpret positive blood cultures (BCs) to distinguish bloodstream infection (BSI) from contamination in BCs drawn with a single venipuncture. During a 2-year period, each positive BC set (comprising six bottles from a single venipuncture) was prospectively categorised by clinicians, bacteriologists and hospital epidemiologists as BSI or contamination. For each case, the number of positive bottles per set, results from Gram staining and microorganism identification were analysed in order to define interpretation guidelines. We analysed 940 positive BC sets. The BSI rate in monomicrobial BC sets was positively correlated with the number of positive bottles. The positive predictive value was 88% with one and 100% with ≥2 positive bottles for Escherichia coli; 100% for Staphylococcus aureus, Pseudomonas and Candida spp., regardless of the number of positive bottles; 3.5%, 61.1%, 78.9% and 100% for coagulase-negative staphylococci (CoNS) with one, two, three and ≥4 positive bottles, respectively. Using a single-sampling strategy, interpretation guidelines for monomicrobial positive BCs are based on the number of positive bottles per set, results from Gram staining and microorganism identification: ≥4 positive bottles (≥2 with Gram-negative bacilli) always led to a diagnosis of BSI. The CoNS BSI rate positively correlates with the number of positive bottles.

Clinical features and outcome of community-acquired bacterial meningitis in adult patients with liver cirrhosis

INTRODUCTION

This study aimed to analyze the clinical features, causative pathogens and therapeutic outcomes of bacterial meningitis in patients with liver cirrhosis.

METHODS

Adult cirrhotic patients with community-acquired bacterial meningitis were evaluated. Clinical data were collected over a 22-year period. For comparison, the clinical features and therapeutic outcomes between patients with and without liver cirrhosis were analyzed.

RESULTS

Liver cirrhosis accounted for 11% (25/217) of the predisposing factors. Significant statistical analysis between the 2 groups (patients with and without liver cirrhosis) included median Glasgow Coma Scale score at presentation, presence of seizure, bacteremia and septic shock. The mean duration between arrival at the emergency room and confirmed diagnosis of bacterial meningitis was 39 hours (range, 2-240 hours). Ten (10/25, 40%) were initially diagnosed with bacterial meningitis, and 6 (6/25, 24%) were initially suggested as having infection of unknown origin. In this study, Klebsiella pneumoniae was the most frequent causative pathogen in patients with liver cirrhosis. The overall case fatality rates for patients with and without liver cirrhosis were 38.5% (74/192) and 64% (16/25), respectively.

CONCLUSIONS

Patients with liver cirrhosis have a more fulminant course with a higher prevalence of disturbed consciousness, bacteremia, seizure and shock. Diagnosis and effective treatment ARE often delayed, resulting in high overall mortality. When patients with liver cirrhosis develop disturbed consciousness, seizures and septicemia, immediate neuroimaging and cerebrospinal fluid studies should be undertaken to determine bacterial meningitis. Early diagnosis and treatment are essential for survival.

Bloodstream infections and setting of onset in persons with spinal cord injury and disorder

STUDY DESIGN

A retrospective cohort study.

OBJECTIVE

Health-care-associated (HCA) bloodstream infection (BSI) has been shown to be a distinct epidemiologic category in the general adult population, but few studies have examined specific patient populations. The objective of this study was to assess characteristics associated with BSI that occurred in the hospital (hospital-acquired, HA BSI), from health-care contact outside the hospital (HCA BSI) or in the community (community-acquired, CA BSI) in veterans with spinal cord injury and disorder (SCI&D).

SETTING

Two United States Department of Veterans Affairs hospitals.

METHODS

All patients with SCI&D with a positive blood culture admitted to study hospitals over a 7-year period (1 October 1997 to 30 September 2004). Demographics, medical characteristics and causative organisms were collected.

RESULTS

Four hundred and thirteen episodes of BSI occurred in 226 patients, with a rate of 7.2 BSI episodes per 100 admissions: 267 (64.7%) were HA BSI, 110 (26.6%) were HCA BSI and 36 (8.7%) were CA BSI. Antibiotic resistance was more common in those with HA BSI (65.5%) compared with that in those with HCA (49.1%, P=0.001) and CA BSI (22.2%, P<0.0001). Methicillin resistance in Staphylococcus aureus was highly prevalent; HA BSI (84.5%), HCA BSI (60.6%) and CA BSI (33.3%).

CONCLUSION

HCA BSI comprises one-quarter of all BSIs in hospitalized patients with SCI&D. Although those with HCA and CA BSI share similarities, several differences in medical characteristics and causal microorganism are noted. Treatment and management strategies for HCA and CA infections need to vary.

An overview of sepsis

The purpose of this paper was to briefly define sepsis, severe sepsis, and septic shock and discuss evidence-based guidelines for implementing a sepsis protocol in the critical care setting. In addition, this article will further educate critical care nurses about sepsis and strategies to improve outcomes in this group of patients.

Examining the association between chest tube-related factors and the risk of developing healthcare-associated infections in the ICU of a community hospital: a retrospective case-control study

OBJECTIVES

The study examined the association between chest tube-related factors and the risk for developing healthcare-associated infections (HAI).

RESEARCH METHODOLOGY

A case-control retrospective chart review was performed on 120 intensive care patients. Eligible patients were 18 years of age or older, had been in the intensive care unit (ICU) for 48 h or more, and had one or more chest tubes.

SETTING

A 20-bed medical-surgical intensive care unit (ICU) of a community hospital in south-western Ontario, Canada.

MAIN OUTCOME MEASURES

Documented diagnosis of hospital-acquired pneumonia or bloodstream infection.

RESULTS

The variable chest tube days was the only chest tube-related factor that was independently associated with HAI (OR = 5.78; p = 0.013). Mechanical ventilation (OR = 4.88; p = 0.002) and outcome length of stay (OR = 0.72; p < or = 0.001) were also independently associated with HAI.

CONCLUSIONS

The risk of infection among patients with chest tubes increases as the number of chest tube days increases. Infection is likely to happen early during admission, which necessitates stringent adherence to infection control strategies, especially during that time frame.

Nationwide study of invasive Pseudomonas aeruginosa infection in Norway: importance of underlying disease

OBJECTIVE

Pseudomonas aeruginosa is an opportunistic pathogen that may cause invasive disease. We describe the epidemiology of invasive P. aeruginosa infection in Norway and identify associated clinical factors.

METHODS

All patients with invasive P. aeruginosa and Pseudomonas not identified at the species level (Pseudomonas spp.) in Norway 1992-2002 were included. Detailed information was collected for all cases during 1999-2002. Population and health institution statistics were obtained from national databases.

RESULTS

In 1999-2002 the incidence rate was 3.16 per 100 000 person-years at risk or 0.20 per 1000 hospital stays. For hospital-acquired infection the rate was 671 per 100 000 person-years as compared with 1.13 for community-acquired infection, and 37 in nursing homes. The highest risk for invasive Pseudomonas disease was found in patients with malignant neoplasms of lymphoid and haematopoietic tissue (risk per 1000 hospital stays 1.9; 95% CI 1.5-2.3) and other diseases of blood and blood-forming organs (2.2; 95% CI 1.2-3.7). The case fatality rate was 35%.

CONCLUSIONS

The incidence of invasive P. aeruginosa infection in this population-based study was much lower than in most single-hospital studies. The nationwide study design and prudent antibiotic use may explain some of the difference. Infection risk is strongly associated with certain underlying diseases.

Bloodstream infections in a geriatric cohort: a population-based study

PURPOSE

Health care-associated infections are those that do not meet the definition of nosocomial but are acquired by patients with extensive exposure to the health care system placing them at higher risk for resistant organisms. This category is particularly common among elderly patients. The objective of this study was to describe and compare the epidemiologic characteristics of community-acquired, health care-associated and nosocomial bloodstream infections in a geriatric population.

METHODS

A population-based, retrospective study of all patients aged 65 years or greater with positive blood cultures (n=636) identified between January 1, 2003 and December 31, 2005 in Olmsted County, Minnesota. Exposures and clinical information were ascertained through complete chart review, utilizing the resources of the Rochester Epidemiology Project. A total of 347 incident patients with bloodstream infection were identified. Bloodstream infections were described as community-acquired, health care-associated or nosocomial using standardized definitions. Variables analyzed included source, isolate, risk factors, and mortality.

RESULTS

The distribution of bloodstream infection cases that were community-acquired, health care-associated, and nosocomial was 159 (46%), 151 (44%), and 37 (10%), respectively. The prevalence of methicillin-resistant Staphylococcus aureus among S. aureus isolates was 54% and 44% for health care-associated and nosocomial cases, respectively. Fourteen-day mortality among bloodstream infection cases was the same in health care-associated and nosocomial infections (15% vs 14%), and was less in community-acquired (6%) cases (P=.04).

CONCLUSIONS

The category of health care-associated infection identified a unique group of geriatric patients at increased risk of methicillin-resistant Staphylococcus aureus infection and with increased mortality.

Comparison of automated strategies for surveillance of nosocomial bacteremia

OBJECTIVE

Surveillance of nosocomial bloodstream infection (BSI) is recommended, but time-consuming. We explored strategies for automated surveillance.

METHODS

Cohort study. We prospectively processed microbiological and administrative patient data with computerized algorithms to identify contaminated blood cultures, community-acquired BSI, and hospital-acquired BSI and used algorithms to classify the latter on the basis of whether it was a catheter-associated infection. We compared the automatic classification with an assessment (71% prospective) of clinical data.

SETTING

An 850-bed university hospital.

PARTICIPANTS

All adult patients admitted to general surgery, internal medicine, a medical intensive care unit, or a surgical intensive care unit over 3 years.

RESULTS

The results of the automated surveillance were 95% concordant with those of classical surveillance based on the assessment of clinical data in distinguishing contamination, community-acquired BSI, and hospital-acquired BSI in a random sample of 100 cases of bacteremia. The two methods were 74% concordant in classifying 351 consecutive episodes of nosocomial BSI with respect to whether the BSI was catheter-associated. Prolonged episodes of BSI, mostly fungemia, that were counted multiple times and incorrect classification of BSI clinically imputable to catheter infection accounted for 81% of the misclassifications in automated surveillance. By counting episodes of fungemia only once per hospital stay and by considering all cases of coagulase-negative staphylococcal BSI to be catheter-related, we improved concordance with clinical assessment to 82%. With these adjustments, automated surveillance for detection of catheter-related BSI had a sensitivity of 78% and a specificity of 93%; for detection of other types of nosocomial BSI, the sensitivity was 98% and the specificity was 69%.

CONCLUSION

Automated strategies are convenient alternatives to manual surveillance of nosocomial BSI.

Prospective hospital-wide studies of 505 patients with nosocomial bacteraemia in 1997 and 2002

We conducted surveys in 1997 and 2002 to determine the rate, underlying sources and outcome of nosocomial bacteraemia. Blood culture results were reviewed daily. All patients with positive cultures drawn >or=48 h after hospitalization were included in the study and their charts were reviewed. The underlying source of infection was determined by pre-defined clinical and/or microbiological criteria. Patients were followed until discharge or death. In 1997 and 2002, 851 and 857 patient-unique cases of bacteraemia were diagnosed, respectively, excluding contaminants; of these, 228 (27%) and 277 (32%) cases, respectively, were hospital acquired (P<0.05). The overall rate decreased from 7.5 to 7.0 per 1,000 admissions (P<0.001). The sources of bacteraemia in 1997 and 2002, respectively, were: intravascular catheters (36% and 27%, P<0.05), urinary tract (8% and 15%, P<0.05), respiratory tract (5% and 13%, P<0.01) and surgical sites (14% and 4%, P<0.001). In one-third of patients, the source of bacteraemia could not be determined. Only 52% and 54%, respectively, of these patients were discharged alive (difference was not significant). In 1997, Staphylococcus aureus was the most frequent isolate (26%), followed by coagulase-negative Staphylococcus (13%) and Klebsiella pneumoniae (11%). By 2002, the incidence of S. aureus had fallen to 11% (P<0.001), acinetobacter was the single most frequently isolated organism (increased from 6% to 17%) (P<0.001). In-hospital mortality associated with acinetobacter bacteraemia (57%) was significantly higher than that for other organisms (31-43%) (P<0.05). In conclusion, prospective surveys of nosocomial bacteraemias provide valuable information, facilitating the pursuit of successful interventions.

Risk factors for hospital-acquired bacteremia

OBJECTIVE

Bacteremia is one of the most serious health problems associated with high morbidity and mortality. The aim of this study was to identify risk factors for bacteremia in daily medical care to facilitate rapid and accurate clinical decisions about treatment.

PATIENTS AND METHODS

We studied 306 inpatients retrospectively. Age, peripheral neutrophil count, C-reactive protein (CRP), platelets, serum total cholesterol, total protein, albumin and cholinesterase were compared in patients with positive- and negative-blood cultures. The associations between blood culture positivity and glucose tolerance, bedridden state, presence of a central venous catheter (CVC) or urinary catheter were examined. On October 14, 2002, strategies for prevention of catheter-related infection were altered in our hospital. We studied the impact of these changes on the risk of bacteremia.

RESULTS

Sixty-seven patients had positive and 239 had negative blood cultures. Age, neutrophil, platelets, total protein, albumin, and cholinesterase were significantly different between the culture-positive patients and the culture-negative patients. Multivariate analysis showed albumin and platelets as independent predictors. The bedridden state and catheter-inserted states (central venous or urinary) conferred significantly higher positive blood culture rates. Multivariate analysis showed using urinary catheters and indwelling femoral CVCs as independent risk factors. There was no significant difference in the blood culture-positive rate before and after the change in prevention strategies; before the change, 6 of 9 catheter-inserted blood culture-positive cases yielded MRSA, while 4 of 12 cultures yielded Staphylococcus epidermidis after the change.

CONCLUSION

Our study highlights the risk factors of bacteremia in vulnerable patients.