Blood cultures do not change management in hospitalized patients with community-acquired pneumonia

Adherence to use of blood cultures according to current national guidelines and their impact in patients with community acquired pneumonia: A retrospective cohort

BACKGROUND

Community acquired pneumonia (CAP) is the most frequent cause of mortality secondary to infectious etiologies. Recommendations about the use of blood cultures in the diagnosis and treatment of CAP has been a contentious topic of debate and ever-changing recommendations.

METHODS

A cohort study was conducted in a community teaching hospital. All the patients that were admitted with a diagnosis of CAP, between January and December of 2019 were included. Sociodemographic and clinical characteristics were obtained. Blood cultures results were obtained, and it was evaluated if they were done in compliance with current recommendations by the Infectious Disease Society of America (IDSA).

RESULTS

721 patients were included in the study. Median age was 68 years and 50% of the patients were male (n = 293). Patients presented from home (84%) and the most common comorbidities were hypertension and diabetes (68% and 31%). 96 patients had positive blood culture and 34% (n = 247) of all the blood cultures were adequately ordered. 80 patients died or went to hospice and the median length of hospital stay in our cohort was 7 days. The multivariate model showed that mortality was associated with positive blood cultures (OR = 3.1 95%CI 1.63-5.87) and appropriateness of blood cultures (OR = 2.96 95% CI 1.2-5.7).

CONCLUSION

Adequate use of blood cultures in patients with CAP might have some association with the outcomes of this disease. However, a prospective study evaluating the utility of this test following current IDSA recommendations is needed to understand their impact in mortality and morbidity.

Effectiveness of Shorter Versus Longer Durations of Therapy for Common Inpatient Infections Associated With Bacteremia: A Multicenter, Propensity-Weighted Cohort Study

BACKGROUND

National guidelines for pneumonia (PNA), urinary tract infection (UTI), and acute bacterial skin and skin structure infection (ABSSSI) do not address treatment duration for infections associated with bacteremia. We evaluated clinical outcomes of patients receiving shorter (5-9 days) versus longer (10-15 days) duration of antibiotics.

METHODS

This was a multicenter retrospective cohort study of inpatients with uncomplicated PNA, UTI, or ABSSSI and associated bacteremia. The primary outcome was clinical failure, a composite of rehospitalization, reinitiation of antibiotics, or all-cause mortality within 30 days of antibiotic completion. Secondary outcomes included individual components of the primary outcome, Clostridioides difficile infection, and antibiotic-related adverse effects necessitating change in therapy. A propensity score-weighted logistic regression model was used to mitigate potential bias associated with nonrandom assignment of treatment duration.

RESULTS

Of 408 patients included, 123 received a shorter treatment duration (median 8 days) and 285 received a longer duration (median 13 days). In the propensity-weighted analysis, the probability of the primary outcome was 13.5% in the shorter group and 11.1% in the longer group (average treatment effect, 2.4%; odds ratio [OR], 1.25; 95% confidence interval [CI], .65-2.40; P = .505). However, shorter courses were associated with higher probability of restarting antibiotics (OR, 1.62; 95% CI, 1.01-2.61; P = .046) and C. difficile infection (OR, 4.01; 95% CI, 2.21-7.59; P < .0001).

CONCLUSIONS

Shorter courses of antibiotic treatment for PNA, UTI, and ABSSSI with bacteremia were not associated with increased overall risk of clinical failure; however, prospective studies are needed to further evaluate the effectiveness of shorter treatment durations.

The clinical significance of simultaneous detection of pathogens from bronchoalveolar lavage fluid and blood samples by metagenomic next-generation sequencing in patients with severe pneumonia

Introduction. Bloodstream infection is a common complication in patients with severe pneumonia and is regarded as an independent risk factor for prediction of poor outcome. Metagenomic next-generation sequencing (mNGS) has been widely applied for pathogen determination of various clinical specimens from patients with infectious diseases. However, the clinical significance of and necessity for simultaneous pathogen detection of both blood samples and bronchoalveolar lavage fluid (BALF) by mNGS in patients with severe pneumonia remains unclear.Hypothesis/Gap Statement. Simultaneous detection of pathogens from both BALF and blood samples in patients with severe pneumonia helps to determine the complication of the bloodstream infection.Aims. This study aimed to elucidate the clinical significance and necessity of pathogen detection simultaneously in both blood samples and BALF samples with the application of mNGS in patients with severe pneumonia.Methods. In this study, 20 patients with severe pneumonia were enrolled and the potential pathogens in both BALF and blood samples were detected simultaneously by conventional microbial examination and mNGS tests. Moreover, multiple consecutive microbial detections were undertaken to investigate the dynamic variation of pathogens during the course of disease progression in two of the 20 patients.Results. In 85 % (17/20) of the patients with severe pneumonia, various pathogens were determined positively in the BALF by mNGS, including 10 cases with bacterial infection, five cases with viral infection and two cases with fungal infection. By contrast, pathogens in 50 % (10/20) of cases could be detected positively in the BALF by conventional microbial tests. Among 17 severe pneumonia patients with mNGS-positive BALF, pathogens were also identified in 10 cases with mNGS-positive blood samples. By contrast, only one patient complicated with a bloodstream infection could be found by conventional bacterial culture. Moreover, the pathogens from BALF were highly consistent with that from blood samples detected by mNGS in the early stage of the disease. With disease progression and after recurrent antibiotic treatment, significant dynamic changes of the microbial species from the BALF and blood samples could be clearly found by mNGS.Conclusions. This study emphasizes the utility of mNGS in the rapid simultaneous detection of pathogens from both BALF and blood samples in patients with severe pneumonia, and could allow determination of bloodstream infection and guide clinicians regarding antimicrobial treatments.

Value of Blood Cultures in the Management of Children Hospitalized with Community-Acquired Pneumonia

Background and objectives

Current guidelines for the management of community-acquired pneumonia (CAP) in children recommend obtaining a blood culture for children with moderate to severe pneumonia; yet, there is no guidance to assess the severity of the disease. Thus, a blood culture is obtained for the majority of children admitted with CAP, regardless of the severity of their symptoms. The study was designed to investigate and identify the prevalence of bacteremia in pediatric patients hospitalized with CAP and to evaluate the clinical and laboratory variables associated with bacteremia.

Methods

We conducted a medical record review of children aged from two months to 18 years diagnosed with CAP between January 1, 2013, and December 31, 2017, at our two urban tertiary centers. We used binary logistic regression analysis and chi-square tests to look at factors associated with blood culture positivity.

Results

A total of 464 patients were admitted with CAP. Blood cultures were obtained in 357 (76.9%) patients; 23 patients had repeated cultures. Fifteen patients had positive cultures: 5/380 (1.3%) were considered true positive results and 10/380 (2.6%) were considered contaminants. Intensive care unit (ICU) admission (OR 5.6 with 95% CI (1- 31), p<0.03), toxic appearance (OR 12.8 with 95% CI (1.3-125), p<0.01), and significantly elevated C-reactive protein (CRP) (>300 mg/L (p<0.01) were associated with bacteremia.

Conclusion

The prevalence of bacteremia among children admitted for CAP is low. The use of routine blood cultures should be reserved for children with moderate to severe pneumonia. Further studies are required to better risk-stratify children with CAP.

Impacts and Challenges of Advanced Diagnostic Assays for Transplant Infectious Diseases

The advanced technologies described in this chapter should allow for full inventories to be made of bacterial genes, their time- and place-dependent expression, and the resulting proteins as well as their outcome metabolites. The evolution of these molecular technologies will continue, not only in the microbial pathogens but also in the context of host-pathogen interactions targeting human genomics and transcriptomics. Their performance characteristics and limitations must be clearly understood by both laboratory personnel and clinicians to ensure proper utilization and interpretation.

Factors affecting bacterial culture positivity in specimens from bronchoscopy in patients with suspected lung cancer

BACKGROUND

Bronchoscopy is important to diagnose lung cancer. However, some patients who undergo bronchoscopic procedures develop respiratory tract infections. Little is known about the proportion of pathogen-positive results in bacterial cultures from diagnostic bronchoscopy samples in patients with suspected lung cancer. This study aimed to determine the rate of positive bacterial cultures after diagnostic bronchoscopy in patients with suspected lung cancer and the relationship among culture results, clinical characteristics, and respiratory tract infections.

METHODS

We retrospectively reviewed the medical records of all immunocompetent patients who underwent bronchoscopy and had culture and histological samples for the diagnosis of peripheral pulmonary lesions from September 2012 to August 2014 at the National Cancer Center in Tokyo. We analyzed data and classified radiological lesions into the following categories: calcifications, cavitations, low-density areas, margin irregularities, and satellite nodules.

RESULTS

The study population consisted of 328 patients (median age, 69 years). We found that 65.9% of patients had malignant lesions and 4.2% of patients had positive cultures for pathogenic bacteria. The number of calcifications (p = 0.002, 95% CI: 2.17-41.10) was significantly higher in patients with positive bacterial isolates, according to the multivariate analysis, and bacterial culture positivity was not associated with the development of respiratory complications after bronchoscopy. Of the three patients with respiratory complications, all presented with cavitations.

CONCLUSION

Because of the low prevalence of positive bacterial cultures in patients with suspected lung cancer, bacterial culture may be limited to specific patients, such as those with calcifications. Lesions with cavitation warrant close monitoring.

Cost effectiveness of pneumococcal urinary antigen in Emergency Department: a pragmatic real-life study

Community-acquired pneumonia (CAP) is frequent and can be life-threatening. Streptococcus pneumoniae is the main bacteria involved, and is susceptible to penicillin A. Rapid microbiological diagnosis could then help reduce the antimicrobial spectrum. The pneumococcal urinary antigen (PUA) test is fast and easy to perform, but its impact on antimicrobial prescription and cost-effectiveness in emergency departments (ED) is not well known. We performed a pragmatic real life retrospective study in an adult ED to assess its usefulness: proportion of positive results, impact on antimicrobial prescriptions and cost-effectiveness. Over 3 years (from January 1st 2012 to December 31st 2014), 979 PUA tests were reutilized in our ED among 1224 patients who consulted for CAP; 51 (5.2%) were positive. Among them, 10 led to a modification of the antimicrobial treatment, but only 7 (14.3%) were in accordance with the results. The total cost of a PUA test is 27€. As only 7 PUA tests led to appropriate antimicrobial modification, we deemed that 972 had no impact, and the potential cost savings, if the test had not been used, would have been 26,244 € (972 × 27) during 3 years, that is 8748 € per year. Thus, it seems that the PUA test should not be generally used in the ED considering its low rate of positivity and the difficulties for physicians to adapt antibiotic treatment accordingly. This attitude change in utilization would lead to substantial cost savings.

Predictors of Bacteraemia in Emergency Department Patients with Pneumonia

Objective

To determine the proportion of patients investigated in an Australian emergency department (ED) for non-hospital-acquired pneumonia with bacteraemia and to identify risk factors for bacteraemia.

Method

Retrospective cohort study of patients with an ED diagnosis of non-hospital-acquired pneumonia in whom blood cultures were taken. Data collected included demographics, history of chronic obstructive pulmonary disease (COPD), immunosuppression, intravenous (IV) drug use or diabetes, prior antibiotic use, clinical features, biochemistry, haematology and blood culture results, ED disposition and pneumonia severity index (PSI) class. Outcomes of interest were the proportion of blood cultures that identified bacteraemia and identification of independent predictors of bacteraemia. Data analysis was by descriptive statistics, odds ratios (OR) and multivariate analysis.

Results

Two hundred patients were studied. The bacteraemia rate was 7% (95% CI=4-11%). IV drug use (OR 16.7, 95% CI=2.65-105) and pulse rate (OR 1.29, 95% CI=1.01-1.65, per 10 beat rise) were independently associated with bacteraemia. Overall, 1/199 patients had a significant broadening of therapy based on a blood culture result (0.5%, 95% CI=0.09-2.8%). On post hoc analysis, using PSI class IV/V or known IV drug use as criteria for blood culture ordering had sensitivity 92.9% (95% CI=64.1-99.6%) and negative predictive value 98.9% (95% CI=93.5-99.9%) for bacteraemia.

Conclusion

7% of blood cultures from patients with non-hospital acquired pneumonia showed bacteraemia. Using the combination of PSI class IV/V or IV drug use as criteria for blood culture ordering shows promise.

Predictive factors of true bacteremia and the clinical utility of blood cultures as a prognostic tool in patients with community-onset pneumonia

Although blood cultures (BCs) are an important component of diagnostic practice for antibiotic management in patients with pneumonia, several studies have questioned whether they should be performed. The objective of this study was to evaluate the predictive factors of bacteremia and the role of BCs in patients with community-onset pneumonia (community-acquired pneumonia and healthcare-associated pneumonia).This study was retrospectively conducted in patients with community-onset pneumonia who were hospitalized at Jeju National University Hospital between January 2012 and December 2014. A true bacteremia (TB) group and a contaminants or negative bacteremia (CNB) group were classified according to the bacterial growth on the BC media and were investigated for the clinical relevance of the BCs.We enrolled 785 patients; the TB group and the CNB group contained 36 patients (4.5%) and 749 (95.4%) patients, respectively. Only 10 patients (1.2%) required a change in antibiotic therapy based on the BC results (3 patients with an escalation, 7 with a de-escalation). There was no significant difference between the community-acquired pneumonia and the healthcare-associated pneumonia groups with regard to the rate of antibiotic change due to the BC results (1.1% vs 1.4%; P = 0.751). Chronic liver disease (odds ratio [OR] 2.973, 95% confidence interval [CI] 1.099-8.037), a confusion, urea, respiratory rate, blood pressure, age ≥65 (CURB-65) score of 4 to 5 points (OR 3.484, 95% CI 1.304-9.307), and Pneumonia Severity Index (PSI) class V (OR 2.405, 95% CI 1.007-5.743) were independently associated with TB. In patients with PSI class V and a CURB-65 score of 4 to 5 points, the TB group tended to show a higher inhospital mortality rate than the CNB group (50.0% vs 29.4%; P = 0.060, 60.0% vs 42.5%; P = 0.480). The areas under the curve for PSI score and CURB-65 score for predicting TB revealed an increased tendency compared with that of C-reactive protein (0.72, 95% CI 0.630-0.809; and 0.72, 95% CI 0.622-0.819 vs 0.629, 95% CI 0.522-0.735, respectively).It seemed reasonable to selectively conduct BC in patients hospitalized with severe community-onset pneumonia based upon its low overall positive rate, its effects on antimicrobial modification, and the associations of TB with the severity indices of pneumonia.

Sending repeat cultures: is there a role in the management of bacteremic episodes? (SCRIBE study)

Background

In the management of bacteremia, positive repeat blood cultures (persistent bacteremia) are associated with increased mortality. However, blood cultures are costly and it is likely unnecessary to repeat them for many patients. We assessed predictors of persistent bacteremia that should prompt repeat blood cultures.

Methods

We conducted a retrospective cohort study of bacteremias at an academic hospital from April 2010 to June 2014. We examined variables associated with patients undergoing repeat blood cultures, and with repeat cultures being positive. A nested case control analysis was performed on a subset of patients with repeat cultures.

Results

Among 1801 index bacteremias, repeat cultures were drawn for 701 patients (38.9 %), and 118 persistent bacteremias (6.6 %) were detected. Endovascular source (adjusted odds ratio [aOR], 7.66; 95 % confidence interval [CI], 2.30-25.48), epidural source (aOR, 26.99; 95 % CI, 1.91-391.08), and Staphylococcus aureus bacteremia (aOR, 4.49; 95 % CI, 1.88-10.73) were independently associated with persistent bacteremia. Escherichia coli (5.1 %, P = 0.006), viridans group (1.7 %, P = 0.035) and β-hemolytic streptococci (0 %, P = 0.028) were associated with a lower likelihood of persistent bacteremia. Patients with persistent bacteremia were less likely to have achieved source control within 48 h of the index event (29.7 % vs 52.5 %, P < .001), but after variable reduction, source control was not retained in the final multivariable model.

Conclusions

Patients with S. aureus bacteremia or endovascular infection are at risk of persistent bacteremia. Achieving source control within 48 h of the index bacteremia may help clear the infection. Repeat cultures after 48 h are low yield for most Gram-negative and streptococcal bacteremias.

Blood Culture in Evaluation of Pediatric Community-Acquired Pneumonia: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVE

Current guidelines strongly recommend collection of blood cultures (BCs) in children requiring hospitalization for presumed moderate to severe bacterial community-acquired pneumonia (CAP). Our objective was to systematically review the international pediatric literature to evaluate how often BCs are positive in hospitalized children with CAP, identify the most commonly isolated pathogens, and determine the impact of positive BCs on clinical management.

METHODS

We identified articles in PubMed and Scopus published from January 1970 through December 2013 that addressed BCs in children with CAP. We extracted total number of BCs collected and prevalence of positive BCs and used meta-regression to evaluate whether subgroups had any impact on prevalence.

RESULTS

Meta-analysis showed that the overall prevalence of positive BCs was 5.14% (95% confidence interval 3.61-7.28). Studies focusing on severe CAP had a significant effect on prevalence (P=.008), at 9.89% (95% CI 6.79-14.19) compared with 4.17% (95% confidence interval 2.79-6.18) for studies not focusing on severe CAP. The most commonly isolated organisms were Streptococcus pneumoniae (76.7%) followed by Haemophilus influenzae (3.1%) and Staphylococcus aureus (2.1%). Contaminants accounted for 14.7%. Only 3 studies reported on BC-driven change in management, with contrasting findings.

CONCLUSIONS

BCs in pediatric CAP identified organisms in only a small percentage of patients, predominantly S. pneumoniae. False-positive BC rates can be substantial. The 3 studies that examined BC-driven changes in management had conflicting results. This systematic review was limited by heterogeneous case definitions, which may overestimate the true prevalence of positive BCs in hospitalized children.

Should all children admitted with community acquired pneumonia have blood cultures taken?

OBJECTIVE

To evaluate the yield of blood cultures and the impact of blood culture results on the adjustment of empiric antibiotic treatment in children hospitalised with community acquired pneumonia (CAP).

METHODS

This was a prospective study conducted at a tertiary hospital in Malaysia, from 1st August 2010 until 31st July 2011. Children aged between 1 mo and 12 y who were admitted for CAP and had blood cultures performed before starting intravenous antibiotics were recruited. Children with congenital pneumonia, immunodeficiency, chronic cardiac or respiratory disorders, nosocomial pneumonia or those on corticosteroids, were excluded. Decision for admission was made by the attending Accident and Emergency physician.

RESULTS

One hundred and seventy-one children were enrolled. The median age was 13 mo (range: 38 d-10 y 3 mo) and 59 % were males. Blood cultures were positive in 1.2 % (2/171) of patients while the contamination rate was 1.8 % (3/171). Doctors altered antibiotics based on blood culture results in only one patient.

CONCLUSIONS

Both the yield and the impact of blood culture results on the adjustment of empiric antibiotic treatment were very small. There was a high contamination rate. The recommended practice of performing blood cultures in all children admitted with CAP should be reviewed.

Can we predict which patients with community-acquired pneumonia are likely to have positive blood cultures?

BACKGROUND

Blood cultures (BC) are commonly ordered during the initial assessment of patients with community-acquired pneumonia (CAP), yet their yield remains low. Selective use of BC would allow the opportunity to save healthcare resources and avoid patient discomfort. The study was to determine what demographic and clinical factors predict a greater likelihood of a positive blood culture result in patients diagnosed with CAP.

METHODS

A structured retrospective systematic chart audit was performed to compare relevant demographic and clinical details of patients admitted with CAP, in whom blood culture results were positive, with those of age, sex, and date-matched control patients in whom blood culture results were negative.

RESULTS

On univariate analysis, eight variables were associated with a positive BC result. After logistic regression analysis, however, the only variables statistically significantly associated with a positive BC were WBC less than 4.5 × 10(9)/L [likelihood ratio (LR): 7.75, 95% CI=2.89-30.39], creatinine >106 μmol/L (LR: 3.15, 95%CI=1.71-5.80), serum glucose<6.1 mmol/L (LR: 2.46, 95%CI=1.14-5.32), and temperature > 38 °C (LR: 2.25, 95% CI =1.21-4.20). A patient with all of these variables had a LR of having a positive BC of 135.53 (95% CI=25.28-726.8) compared to patients with none of these variables.

CONCLUSIONS

Certain clinical variables in patients with CAP admitted to hospitals do appear to be associated with a higher probability of a positive yield of BC, with combinations of these variables increasing this likelihood. We have identified a subgroup of CAP patients in whom blood cultures are more likely to be useful.

Impact of blood cultures on the changes of treatment in hospitalized patients with community-acquired pneumonia

BACKGROUND

Initial blood cultures (BCs) with severe community-acquired pneumonia (CAP) are warranted. However, other than severity, the specific contributing factors that affect the decision to change antimicrobial agents have not been evaluated previously.

METHODS

Consecutive adults with CAP hospitalized between January 2008 and December 2010 were assessed retrospectively. We enrolled those who were over 18 years old with typical symptoms of pneumonia and with an infiltrate consistent with pneumonia, from which 2 sets of BCs were obtained. Those who had been immunocompromised, hospitalized, or prescribed antibiotics in the past 30 days were excluded. We retrospectively assessed the factors contributing to the change in antimicrobial agents as well as the frequency of these changes in the enrolled patients based on the initial BC results.

RESULTS

In total, 793 patients with initial diagnosis of CAP were admitted; 399 met the inclusion criteria. Among them, 386 were made definitive diagnosis of CAP after admission (the remaining 13 were made alternative diagnosis [non-pneumonia illnesses]). BC results were positive in 17 (4.4%) out of 386 CAP patients, among whom antimicrobial therapy was changed based on the BC results in 8 (2.1%) (Pneumonia Severity Index [PSI] grade IV; 2, PSI grade V; 6). Alternative diagnosis after admission was contributing factors for changing antimicrobial agents based on the positive blood culture results.

CONCLUSIONS

The use of BCs should be limited to patients with very severe cases. It would be helpful to find alternative diagnosis and modify treatment.

Emergency Department Pneumonia Patients Who do not Meet the Six-Hour Criteria for Antibiotic Administration: Do They Have a Different Clinical Presentation?

Background

The Joint Commission (JC) has set a quality of care standard for emergency department (ED) patients diagnosed with community acquired pneumonia (CAP) that states that they are to receive antibiotics within six hours of presentation to the ED. Hospitals have been able to demonstrate that the majority of patients meet these criteria, yet there are still many who do not. Previously published studies have reported that there are several issues that contribute to prolonged times to antibiotic administration including ED crowding and atypical clinical presentations. This study was undertaken to identify factors existing early in the patient encounter that may be associated with failure to meet the Joint Commission’s six-hour standard for antibiotic administration.

Methods

This was an IRB-approved, retrospective observational study covering 36 months in an academic emergency department. All adults with an admission diagnosis of CAP were eligible but were excluded if their discharge diagnosis was not CAP, if hospitalized within the previous 14 days, or if HIV positive. Univariate analysis and multiple logistic regression with stepwise variable selection were performed comparing patients who met and did not meet JC standards. The analysis included demographics (age, sex), chief complaint at triage and to doctor (fever, dyspnea, cough, chest pain, weakness/fatigue, abdominal pain), presence of altered mental status, triage vital signs, co-morbidities, day of week and time of day of presentation.

Results

A total of 736 cases were eligible; 199 cases met exclusion criteria; 43 charts were unavailable; 494 were included in the study group (363 with complete antibiotic time records; 131 were incomplete). From the univariate analysis, respiratory rate (RR) and oxygen saturation were the only factors that met Bonferroni criteria for statistical significance when comparing those who met and did not meet the JC six-hour criteria (RR 25 ± 9 vs 22 ± 6 breaths/minute, respectively, P = 0.002; oxygen saturation 87 ± 10% vs 92 ± 5%, respectively, P < 0.001). Multiple logistic regression identified triage pulse rate, oxygen saturation, presence of altered mental status, hour of day, and day of week as variables associated with time to antibiotic administration. Chances for meeting the standard were increased by 10% for each 5-beat increase in pulse rate or 1% decrease in oxygen saturation. If the person exhibited altered mental status, they were > 3.5 times more likely to meet the 6-hour criteria. If they presented to ED between 3 PM and 10 PM chances of meeting criteria were reduced by about 65%. If they presented on a Thursday, chances improved 2.8 times.

Conclusions

Compared to patients who did meet Joint Commission criteria, those who did not receive antibiotics within 6 hours were likely to have triage pulse rates and O₂ saturation levels closer to normal, thus contributing to diagnostic uncertainty. They were also likely to present to the ED at the most crowded time of day. Likelihood to meet JC criteria was improved if O₂ saturation was below normal, pulse rate was elevated, if they exhibited mental confusion, or if they presented to the ED very early or very late in the day, or on a lower census day.

Rapid diagnostic testing for community-acquired pneumonia: can innovative technology for clinical microbiology be exploited?

Two nonsynchronous events have affected the management of community-acquired pneumonia (CAP): spiraling empiricism for CAP and the "golden era" of clinical microbiology. The development of broad-spectrum antibiotics has led to widespread empiric use without ascertaining the etiology of the infecting microbe. Unfortunately, this approach clashes with the second event, which is the advent of molecular-based microbiology that can identify the causative pathogen rapidly at the point of care. The urinary antigen is a most effective rapid test that has allowed targeted therapy for Legionnaire disease at the point of care. The high specificity (> 90%) allows the clinician to administer appropriate anti-Legionella therapy based on a single rapid test; however, its low sensitivity (76%) means that a notable number of cases of Legionnaire disease will go undiagnosed if other tests, especially culture, are not performed. Further, culture for Legionella is not readily available. If a culture is not performed, epidemiologic identification of the source of the bacterium cannot be ascertained by molecular fingerprinting of the patient and the putative source strain. We recommend resurrection of the basic principles of infectious disease, which are to identify the microbial etiology of the infection and to use narrow, targeted antimicrobial therapy. To reduce antimicrobial overuse with subsequent antimicrobial resistance, these basic principles must be applied in concert with traditional and newer tests in the clinical microbiology laboratory.

Usefulness of initial blood cultures in patients admitted with pneumonia from an emergency department in Japan

Guidelines recommend obtaining blood cultures for all patients admitted with pneumonia. However, recent American studies have reported the low impact of these cultures on antibiotic therapy. Our aim was to investigate the incidence of bacteremia and change of therapy in admitted pneumonia patients from whom blood cultures were obtained in the emergency department (ED). A retrospective, observational, cohort study was conducted on consecutive patients (age >/=12 years) with pneumonia hospitalized through the ED between January 1 and December 31, 2006, in an urban teaching hospital in Japan. Data were collected on antibiotic sensitivities, empirical antibiotics, and changes of antibiotic management. Blood cultures were classified as positive, negative, or contaminant, based on previously established criteria. Out of 164 consecutive cases, blood cultures were positive in 6 patients (3.7%; 95% confidence interval [CI], 0.8%-6.6%), contaminated in 6 (3.7%), and negative in 152 (92.7%). Of the 6 bacteremic patients, 2 cases were likely to have been caused by concomitant diseases. Blood culture results altered therapy for 4 patients (2.4% of 164; 95% CI, 0.7%-6.1%), of whom 2 patients (1.2%; 95% CI, 0.1%-4.3%) had their coverage narrowed, 1 patient (0.6%; 95% CI, 0.0%-3.4%) had coverage broadened, and 1 patient had altered therapy before the drug sensitivities were reported. Considering cost and workload, the overall total annual cost was <euro>758 631 (<euro>107 = 1 $US in June 2008). Blood cultures could identify organisms in only a few patients with pneumonia and rarely altered antibiotic management even in patients with positive cultures. It may not be necessary to obtain blood cultures for patients admitted with pneumonia.

Blood cultures for community-acquired pneumonia: are they worthy of two quality measures? A systematic review

BACKGROUND

Obtaining blood cultures (BCs) for patients hospitalized with community-acquired-pneumonia (CAP) has been recommended by experts and used as a measure of quality of care. However, BCs are infrequently positive in these patients and their effect on clinical management has been questioned.

PURPOSE

We performed a systematic review of the literature to determine the impact of BCs on clinical management in CAP requiring hospitalization and thus its appropriateness as a quality measure.

DATA SOURCES

We searched MEDLINE, MEDLINE In-Process, and the Cochrane databases for English-language studies that reported the effect of BCs on management of adults hospitalized with CAP. We also searched the reference lists of included studies and background articles and asked experts to review our list for completeness.

STUDY SELECTION

Studies were chosen if they included adults admitted to the hospital with CAP, BCs were obtained at admission, and BC-directed management changes were reported.

DATA EXTRACTION

We abstracted study design, BC positivity, and frequency of BC-directed management changes.

DATA SYNTHESIS

Fifteen studies, all with observational cohort design, were identified and reviewed. Two included only patients with BCs positive for pneumococcus, yielding 13 studies for the primary analysis. BCs were true-positive in 0% to 14% of cases. They led to antibiotic narrowing in 0% to 3% of patients and to antibiotic broadening ultimately associated with a resistant organism in 0% to 1% of patients.

CONCLUSIONS

BCs have very limited utility in immunocompetent patients hospitalized with CAP. Pneumonia quality measures that include BCs should be reassessed.

The Centers for Medicare and Medicaid Services (CMS) community-acquired pneumonia core measures lead to unnecessary antibiotic administration by emergency physicians

OBJECTIVES

The objectives were to assess emergency physician (EP) understanding of the Centers for Medicare and Medicaid Services (CMS) core measures for community-acquired pneumonia (CAP) guidelines and to determine their self-reported effect on antibiotic prescribing patterns.

METHODS

A convenience sample of EPs from five medical centers in North Carolina was anonymously surveyed via a Web-based instrument. Participants indicated their level of understanding of the CMS CAP guidelines and the effects on their prescribing patterns for antibiotics.

RESULTS

A total of 121 EPs completed the study instrument (81%). All respondents were aware of the CMS CAP guidelines. Of these, 95% (95% confidence interval [CI] = 92% to 98%) correctly understood the time-based guidelines for antibiotic administration, although 24% (95% CI = 17% to 31%) incorrectly identified the onset of this time period. Nearly all physicians (96%; 95% CI = 93% to 99%) reported institutional commitment to meet these core measures, and 84% (95% CI = 78% to 90%) stated that they had a department-based CAP protocol. More than half of the respondents (55%; 95% CI = 47% to 70%) reported prescribing antibiotics to patients they did not believe had pneumonia in an effort to comply with the CMS guidelines, and 42% (95% CI = 34% to 50%) of these stated that they did so more than three times per month. Only 40% (95% CI = 32% to 48%) of respondents indicated a belief that the guidelines improve patient care. Of those, this was believed to occur by increasing pneumonia awareness (60%; 95% CI = 52% to 68%) and improving hospital processes when pneumonia is suspected (86%; 95% CI = 80% to 92%).

CONCLUSIONS

Emergency physicians demonstrate awareness of the current CMS CAP guidelines. Most physicians surveyed reported the presence of institutional protocols to increase compliance. More than half of EPs reported that they feel the guidelines led to unnecessary antibiotic usage for patients who are not suspected to have pneumonia. Only 40% of EPs believe that CAP awareness and expedient care resulting from these guidelines has improved overall pneumonia-related patient care. Outcome-based data for non-intensive care unit CAP patients are lacking, and EPs report that they prescribe antibiotics when they may not be necessary to comply with existing guidelines.