The contribution of blood cultures to the clinical management of adult patients admitted to the hospital with community-acquired pneumonia: a prospective observational study

European society of clinical microbiology and infectious diseases guidelines for antimicrobial stewardship in emergency departments (endorsed by European association of hospital pharmacists)

SCOPE

This European Society of Clinical Microbiology and Infectious Diseases guideline provides evidence-based recommendations to support a selection of appropriate antibiotic use practices for patients seen in the emergency department (ED) and guidance for their implementation. The topics addressed in this guideline are (a) Do biomarkers or rapid pathogen tests improve antibiotic prescribing and/or clinical outcomes? (b) Does taking blood cultures in common infectious syndromes improve antibiotic prescribing and/or clinical outcomes? (c) Does watchful waiting without antibacterial therapy or with delayed antibiotic prescribing reduce antibiotic prescribing without worsening clinical outcomes in patients with specific infectious syndromes? (d) Do structured culture follow-up programs in patients discharged from the ED with cultures pending improve antibiotic prescribing?

METHODS

An expert panel was convened by European Society of Clinical Microbiology and Infectious Diseases and the guideline chair. The panel selected in consensus the four most relevant antimicrobial stewardship topics according to pre-defined relevance criteria. For each main question for the four topics, a systematic review was performed, including randomized controlled trials and observational studies. Both clinical outcomes and stewardship process outcomes related to antibiotic use were deemed relevant. The literature searches were conducted between May 2021 and March 2022. In April 2022, the panel members were formally asked to suggest additional studies that were not identified in the initial searches. Data were summarized in a meta-analysis if possible or otherwise summarized narratively. The certainty of the evidence was classified according to the Grading of Recommendations Assessment, Development and Evaluation criteria. The guideline panel reviewed the evidence per topic critically appraising the evidence and formulated recommendations through a consensus-based process. The strength of the recommendations was classified as strong or weak. To substantiate the implementation process, implementation trials or observational studies describing facilitators/barriers for implementation were identified from the same searches and were summarized narratively.

RECOMMENDATIONS

The recommendations on the use of biomarkers and rapid pathogen diagnostic tests focus on the initiation of antibiotics in patients admitted through the ED. Their effect on the discontinuation or de-escalation of antibiotics during hospital stay was not reported, neither was their effect on hospital infection prevention and control practices. The recommendations on watchful waiting (i.e. withholding antibiotics with some form of follow-up) focus on specific infectious syndromes for which the primary care literature was also included. The recommendations on blood cultures focus on the indication in three common infectious syndromes in the ED explicitly excluding patients with sepsis or septic shock. Most recommendations are based on very low and low certainty of evidence, leading to weak recommendations or, when no evidence was available, to best practice statements. Implementation of these recommendations needs to be adapted to the specific settings and circumstances of the ED. The scarcity of high-quality studies in the area of antimicrobial stewardship in the ED highlights the need for future research in this field.

Diagnostic value of ultrasound for community-acquired pneumonia in children and its correlation with serum PCT level and PCIS

OBJECTIVE

This study aimed to evaluate the diagnostic value of ultrasound for community-acquired pneumonia (CAP) in children.

METHODS

Clinical information of children diagnosed with CAP and a control group of healthy children was collected, and lung ultrasound detection was performed. The lung ultrasound score (LUS) was assessed, and venous blood samples were collected. Serum indexes, including white blood cell count, were analyzed using an automatic immunoassay analyzer, while serum procalcitonin (PCT) level was measured using an enzyme-linked immunosorbent assay. The pediatric critical illness score (PCIS) was also performed for all subjects.

RESULTS

White blood cell count, absolute neutrophil count, and respiratory index were significantly higher in the CAP group than those in the control group, while the oxygenation index was markedly lower. Ultrasound detection results showed that the CAP group exhibited significantly higher detection rates of pleural effusion, interstitial lung changes, lung consolidation, B-lines, air bronchogram signs, and reduced or absent lung sliding signs compared with the control group. In addition, the LUS and PCT levels were markedly higher in the CAP group, while the PCIS was notably lower. Further analysis exhibited that the LUS in the CAP group was significantly positively correlated with PCT levels and negatively correlated with PCIS. The receiver operating characteristic curve indicated that the area under the curve of LUS for diagnosing children with lung infection was 0.841.

CONCLUSION

LUS is closely related to serum PCT level and PCIS. Lung ultrasound detection demonstrates high sensitivity and specificity, indicating its valuable clinical diagnostic utility for CAP in children.

Investigation of etiology of community-acquired pneumonia in hospitalized patients in a tertiary hospital of São Paulo City, Brazil

BACKGROUND

Community-Acquired Pneumonia (CAP) is the primary cause of hospitalization in the United States and the third leading cause of death in Brazil. The gold standard for diagnosing the etiology of CAP includes blood culture, Gram-stained sputum, and sputum culture. However, these methods have low sensitivity. No studies investigating the etiology of CAP have been conducted in Brazil in the last 20-years, and the empirical choice of antimicrobials is mainly based on the IDSA guidelines. This is the first national study with this aim, and as a result, there's potential for the Brazilian consensus to be impacted and possibly modify its guidelines rather than adhering strictly to the IDSA's recommendations.

METHODS

The aim of this study is to identify the main microorganisms implicated in CAP by employing a multiplex Polymerase Chain Reaction (mPCR) at the foremost public hospital in Brazil. All patients who were admitted to the emergency department and diagnosed with severe CAP underwent an mPCR panel using nasopharyngeal and oropharyngeal swabs, with the aim of detecting 13 bacterial and 21 viral pathogens.

RESULTS

A total of 169 patients were enrolled in the study. The mPCR panel identified an etiological agent in 61.5% of patients, with viruses being the most common (42.01%), led by Rhinovirus, followed by Influenza and Coronavirus (non-SARS-CoV-2). Bacterial agents were identified in 34.91% of patients, with S. pneumoniae being the most common, followed by H. influenzae, M. catarrhalis, and S. aureus. Additionally, we found that the prescription for 92.3% of patients could be modified, with most changes involving de-escalation of antibiotics and antiviral therapy.

CONCLUSION

Our study revealed different etiological causes of CAP than those suggested by the Brazilian guidelines. Using molecular diagnostic tests, we were able to optimize treatment by using fewer antibiotics.

Evaluation of the usefulness of culture of induced sputum and the optimal timing for the collection of a good-quality sputum sample to identify causative pathogen of community-acquired pneumonia in young children: A prospective observational study

BACKGROUND

The usefulness of an induced sputum in the identification of causative bacteria of community-acquired pneumonia (CAP) in young children is controversial. This study aimed to investigate the significance of the implementation of an induced sputum culture among children with CAP and the impact of prior use of antimicrobial agents on the quality of the sample and result of the culture.

METHODS

This prospective study included 96 children hospitalized for acute bacterial CAP whose sputum samples were collected by suctioning from the hypopharynx through the nose. The samples were evaluated for their quality using Geckler classification, and the result of this conventional culture method was compared to that of a clone library analysis of the bacterial 16S rRNA gene sequence for each sample.

RESULTS

The concordance between bacteria isolated by sputum culture and the most predominant bacteria identified by a clonal library analysis was significantly higher in the samples judged as a good quality (Geckler 5, 90%) than in others (70%). The rate of good-quality sputum sample was significantly higher in samples collected from patients without prior antimicrobial therapy (70%) than in those from patients with it (41%). The concordance between the two methods was significantly higher in the former (88%) than in the latter population (71%).

CONCLUSION

Bacteria isolated by the culture using good-quality sputum samples collected from children with CAP were more likely to be causative pathogens. Sputum samples collected before starting antimicrobial therapy showed better quality and higher probability of the identification of causative pathogens.

Predictors of stroke-associated pneumonia and the predictive value of neutrophil percentage-to-albumin ratio

BACKGROUND

Early recognition of stroke-associated pneumonia (SAP) is critical to reducing morbidity and mortality associated with SAP. This study investigated the predictors of SAP, and the predictive value of the neutrophil percentage-to-albumin ratio (NPAR) for SAP.

METHODS

This retrospective cohort study was conducted among stroke patients admitted to Jordan University Hospital from January 2015 to May 2021. Multivariable logistic regression was used to identify independent predictors for SAP. The predictive performance was assessed using C-statistics, described as the area under the receiver-operating characteristic curve (AUC, ROC) with a 95% confidence interval.

RESULTS

Four hundred and six patients were included in the analysis, and the prevalence of SAP was 19.7%. Multivariable logistic analysis showed that males (Adjusted Odds Ratio (AOR): 5.74; 95% Confidence Interval (95%CI): 2.04-1 6.1)], dysphagia (AOR: 5.29; 95% CI: 1.80-15.5), hemiparesis (AOR: 3.27; 95% CI: 1.13-9.47), lower GCS score (AOR: 0.73; 95% CI: 0.58-0.91), higher levels of neutrophil-lymphocyte ratio (NLR) (AOR: 1.15; 95% CI: 1.07-1.24), monocyte-lymphocyte ratio (MLR) (AOR: 1.49; 95% CI: 1.13-1.96), and neutrophil percentage to albumin ratio (NPAR) (AOR: 1.53; 95% CI: 1.33-1.76) were independent predictors of SAP. The NPAR demonstrated a significantly higher AUC than both the NLR (0.939 versus 0.865, Z = 3.169, p = 0.002) and MLR (0.939 versus 0.842, Z = 3.940, p < 0.001). The AUCs of the NLR and MLR were comparable (0.865 versus 0.842, Z = 1.274, p = 0.203).

CONCLUSION

Male gender, dysphagia and hemiparesis were the strongest predictors of SAP, and NPAR has an excellent performance in predicting SAP which was better than high NLR and MLR.

Discordance of the Urinary and Pleural Fluid Antigen Test and False Positive for Streptococcus pneumoniae in Empyema Secondary to Necrotizing Bacterial Pneumonia

Empyema is a severe complication of pneumonia with high morbidity and mortality rates. Rapid diagnosis and tailoring of antibiotic therapy are crucial to treatment success for these severe bacterial lung infections. A Streptococcus pneumoniae (S. pneumonia) antigen test drawn from the pleural fluid rather than a urine sample has been found to have equivalent diagnostic utility to the urinary antigen test. Discordance between these tests is rare. We report a case of a 69-year-old female with CT imaging findings consistent with empyema and a bronchopulmonary fistula. A rapid S. pneumonia antigen test was negative from the urinary sample but positive when drawn from a patient's pleural fluid sample. Final pleural fluid cultures resulted in Streptococcus constellatus (S. constellatus). This case demonstrates discordance between the results of urinary and pleural fluid S. pneumoniae antigen tests, representing a potential pitfall in using rapid antigen testing on pleural fluid samples. False positives for the S. pneumoniae antigen in patients with viridans streptococci infections have been documented due to the cross-reactivity of cell wall proteins in different streptococcal species. Physicians encountering bacterial pneumonia of unknown etiology complicated by empyema should understand the potential for discordance and false positives using this diagnostic method.

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.

Diagnostic des pneumonies aiguës communautaires aux urgences et distinction entre étiologie virale ou bactérienne

La pandémie actuelle liée à l’émergence du SARSCoV-2 en 2019 a considérablement modifié la perception des médecins de l’impact des virus respiratoires et de leur rôle dans les pneumonies aiguës communautaires (PAC). Alors que plus de 25 % des tableaux de PAC chez l’adulte étaient d’origine virale, les virus respiratoires étaient souvent perçus comme des agents pathogènes peu graves. Devant le défi que représente encore à nos jours la documentation microbiologique d’une PAC, l’instauration d’un traitement empirique par antibiotiques est souvent réalisée aux urgences. La pandémie de COVID-19 a surtout mis en exergue le rôle déterminant de la biologie moléculaire et du scanner thoracique dans l’algorithme diagnostique de la PAC. En effet, un diagnostic rapide et fiable est la clé pour améliorer les mesures de précaution et réduire la prescription inutile d’antibiotiques. Du fait de prises en charges très différentes, il est nécessaire de distinguer l’étiologie virale de la bactérienne d’une PAC.

Application of Metagenomic Next-Generation Sequencing (mNGS) Using Bronchoalveolar Lavage Fluid (BALF) in Diagnosing Pneumonia of Children

Pneumonia is the leading cause of death in children; the pathogens are often difficult to diagnose. In this study, the performance of metagenomic next-generation sequencing (mNGS) using bronchoalveolar lavage fluid (BALF) samples from 112 children with confirmed pneumonia has been evaluated. mNGS performed a significantly higher positive detection rate (91.07%, 95% confidence interval [CI] 83.80% to 95.40%) and coincidence rate against the final diagnosis (72.32%, 95% CI 62.93% to 80.15%) than that of conventional methods (70.54%, 95% CI 61.06% to 78.58% and 56.25%, 95% CI 46.57% to 65.50%, respectively) (P < 0.01 and P < 0.05, respectively). Bacteria, viruses, and their mixed infections were common in children with pneumonia. Streptococcus pneumoniae was the most common bacterial pathogen in children with pneumonia, while Haemophilus parainfluenzae and Haemophilus influenzae seemed more likely to cause nonsevere pneumonia in children. In contrast, human cytomegalovirus (CMV) infection and the simultaneous bacterial infections could cause severe pneumonia, especially in children with underlying diseases. After adjustments of antibiotics based on mNGS and conventional methods, the conditions improved in 109 (97.32%) children. mNGS of BALF samples has shown great advantages in diagnosing the pathogenic etiology of pneumonia in children, especially when considering the limited volumes of BALF and the previous use of empirical antibiotics, contributing to the timely adjustment of antibiotic treatments, which can potentially improve the prognosis and decrease the mortality. IMPORTANCE Our study indicates high efficiency of mNGS using BALF for the detection of causative pathogens that cause pneumonia in children. mNGS can be a potential diagnostic tool to supplement conventional methods for children's pneumonia.

ESTIMATING THE RISK OF BACTERAEMIA IN HOSPITALISED PATIENTS WITH PNEUMOCOCCAL PNEUMONIA

Objective To construct a prediction model for bacteraemia in patients with pneumococcal community-acquired pneumonia (P-CAP) based on variables easily obtained at hospital admission. MethodsThis prospective observational multicentre derivation-validation study was conducted in patients hospitalised with P-CAP between 2000-2020. All cases were diagnosed based on positive urinary antigen tests in the emergency department and had blood cultures taken on admission. A risk score to predict bacteraemia was developed. Results We included 1783 patients with P-CAP (1195 in the derivation and 588 in the validation cohort). A third (33.3%) of the patients had bacteraemia. In the multivariate analysis, the following were identified as independent factors associated with bacteraemia: no influenza vaccination the last year, no pneumococcal vaccination in the last 5 years, blood urea nitrogen (BUN) ≥30 mg/dL, sodium <130 mmol/L, lymphocyte count <800/µl, C-reactive protein ≥200 mg/L, respiratory failure, pleural effusion and no antibiotic treatment before admission. The score yielded good discrimination (AUC 0.732; 95% CI: 0.695-0.769) and calibration (Hosmer-Lemeshow p-value 0.801), with similar performance in the validation cohort (AUC 0.764; 95% CI:0.719-0.809). Conclusions We found nine predictive factors easily obtained on hospital admission that could help achieve early identification of bacteraemia. The prediction model provides a useful tool to guide diagnostic decisions.

Effect of positive microbiological testing on antibiotic de-escalation and outcomes in community-acquired pneumonia: A propensity score analysis

OBJECTIVES

The usefulness of routine microbiological testing for rationalizing antibiotic use in hospitalized patients with community-acquired pneumonia (CAP) continues to be a subject of debate. We aim to determine the effect of positive microbiological testing on antimicrobial de-escalation and clinical outcomes in CAP.

METHODS

A retrospective analysis of a prospectively collected cohort of non-immunosuppressed adults hospitalized with CAP was performed. The primary study outcome was antimicrobial de-escalation. Secondary outcomes included 30-day case-fatality rate, adverse events, and CAP recurrence. Adjustment for confounders, was performed by inverse probability weighting propensity score (IPW-PS), logistic regression and cause-specific Cox model.

RESULTS

Of 3677 patients with CAP, 1924 (52.3%) had any positive microbiological test. Antimicrobial de-escalation was performed in 648/1924 (33.7%) of patients with positive microbiological testing and in 179/1753 (10.2%) of those with non positive results. When propensity score was entered into the multivariate analysis, positive microbiological testing (Adjusted Odds Ratio [AOR] 2.59 (1.96 - 3.41) and clinical stability at day 3 (AOR 1.87; 1.45 - 2.10) were two of the main factors independently associated with antimicrobial de-escalation. After applying an adjusted cause-specific Cox model, antimicrobial de-escalation was not associated with a higher 30-day case-fatality rate (Adjusted Hazard Ratio [AHR] 0.44; 0.14 - 1.43), higher frequency of adverse events (AHR 0.77; 0.53 - 1.12) or CAP recurrence (AHR 0.77; 0.45 - 1.28).

CONCLUSIONS

Antimicrobial de-escalation was more often performed in hospitalized patients with CAP who had positive microbiological tests than in those with non positive results, and it did not adversely affect relevant clinical outcomes.

Use of combined treatment of 3rd-generation cephalosporin, azithromycin and antiviral agents on moderate SARs-CoV-2 patients in South Korea: A retrospective cohort study

OBJECTIVES

To assess efficacy and safety of the combined treatment of antibiotics (3rd-generation cephalosporin and azithromycin) and antiviral agents (lopinavir/ritonavir or hydroxychloroquine) on moderate COVID-19 patients in South Korea.

METHODS

A retrospective cohort study of the 358 laboratory-confirmed SARS-CoV-2 (COVID-19) patients was conducted. 299 patients met inclusion criteria for analysis. Propensity score matching (PSM) and Cox regression method were used to control and adjust for confounding factors. Mild to moderate COVID-19 patients were managed with either CA/LoP (cephalosporin, azithromycin, and lopinavir/ritonavir) (n = 57), CA/HQ (cephalosporin, azithromycin, and hydroxychloroquine) (n = 25) or standard supportive care (n = 217). We analyzed the association between treatment group and standard supportive group in terms of three endpoints: time to symptom resolution, time to viral clearance, and hospital stay duration. Using propensity-score matching analysis, three rounds of propensity-matching analysis were performed to balance baseline characteristics among three cohorts.

RESULTS

Kaplan-Meier curves fitted using propensity score-matched data revealed no significant differences on time to symptom resolution, time to viral clearance, hospital stay duration among the three treatment arms (CA/LoP vs Standard, log-rank p-value = 0.2, 0.58, and 0.74 respectively for the three endpoints) (CA/HQ vs Standard, log-rank p-value = 0.46, 0.99, and 0.75 respectively). Similarly, Cox regression analysis on matched cohorts of CA/LoP and standard supportive group showed that hazard ratios of time to symptom resolution (HR: 1.447 [95%-CI: 0.813-2.577]), time to viral clearance(HR: 0.861, [95%-CI: 0.485-1.527]), and hospital stay duration (HR: 0.902, [95%-CI: 0.510-1.595]) were not significant. For CA/HQ and standard supportive group, hazard ratios of the three endpoints all showed no statistical significance (HR: 1.331 [95%-CI:0.631-2.809], 1.005 [95%-CI:0.480-2.105], and 0.887, [95%-CI:0.422-1.862] respectively). No severe adverse event or death was observed in all groups.

CONCLUSIONS

Combined treatment of 3rd cephalosporin, azithromycin and either low-dose lopinavir/ritonavir or hydroxychloroquine was not associated with better clinical outcomes in terms of time to symptom resolution, time to viral clearance, and hospital stay duration compared to standard supportive treatment alone. Microbiological evidence should be closely monitored when treating SARS-CoV-2 patients with antibiotics to prevent indiscreet administration of empirical antimicrobial treatments.

Urinary Antigen Testing for Respiratory Infections: Current Perspectives on Utility and Limitations

Pneumonia is a leading cause of hospitalization and death due to infection worldwide. Streptococcus pneumoniae and Legionella pneumophila remain among the most commonly identified bacterial pathogens. Unfortunately, more than half of all pneumonia cases today lack an etiologic diagnosis due to limitations in traditional microbiological methods like blood and sputum cultures, which are affected by poor sample collection, prior antibiotic administration, and delayed processing. Urinary antigen tests (UATs) for S. pneumoniae and L. pneumophila have emerged as powerful tools for improving the diagnosis of bacterial respiratory infections, enabling physicians to administer early directed therapy and improve antimicrobial stewardship. UATs are simple, rapid, and non-invasive diagnostic tests with high specificity (>90%) and moderate sensitivity (<80%). The potential impact of urinary antigen testing is especially significant for respiratory infections caused by Legionella. While all recommended community-acquired pneumonia (CAP) therapies are adequate for treating pneumococcal pneumonia, only certain antibiotics are effective against Legionella. Delayed therapy for Legionella is associated with worse clinical outcomes, which underscores the importance of rapid diagnostic methods like UATs. Despite their potential impact, current American Thoracic Society and Infectious Diseases Society of America (ATS/IDSA) guidelines argue against the routine use of urinary antigen testing for S. pneumoniae and L. pneumophila, except in patients with severe CAP and those with epidemiological risk factors for Legionella. Further research is necessary to evaluate the impact of early targeted treatment due to positive UAT results, as well as optimal strategies for UAT utilization. The purpose of this review is to summarize the UATs available for bacterial respiratory infections, describe current guidelines on their usage, and assess their impact on clinical outcomes and targeted therapy.

New testing guidelines for community-acquired pneumonia

PURPOSE OF REVIEW

The purpose of this article is to review diagnostic testing recommendations outlined in the current American Thoracic Society (ATS)/Infectious Diseases Society of America (IDSA) community-acquired pneumonia (CAP) guideline and the 2021 ATS guideline for noninfluenza respiratory viruses.

RECENT FINDINGS

Diagnostic testing in CAP with gram stain, lower respiratory and blood cultures, Streptococcal and Legionella urinary antigens are not routinely recommended unless identified as severe CAP or with risk factors for Methicillin-resistant Staphylococcus aureus (MRSA) or Pseudomonas aeruginosa infection. Influenza virus testing remains a strong recommendation during periods of community viral spread.An additional 2021 ATS clinical practice guideline reviewed the use of molecular testing for noninfluenza viral pathogens in adults with suspected CAP and recommended testing in those hospitalized with severe CAP and/or various immunocompromising conditions.

SUMMARY

Diagnostic testing remains an important component of confirming and treating CAP. The CAP guideline includes recommendations surrounding diagnostic testing with lower respiratory gram stain and culture, blood cultures, Legionella and Pneumococcal urinary antigen, influenza viral testing and serum procalcitonin.There is a strong recommendation to obtain influenza virus testing during periods of community spread. However, the use of other diagnostics such as gram stain, lower respiratory and blood culture, and urinary antigen testing are dependent on severity of illness and whether a patient has been identified as having strong risk factors for MRSA or P. aeruginosa infection. The 2021 ATS clinical practice document did not routinely recommend testing noninfluenza respiratory viruses unless identified as having severe CAP and/or various immunocompromising conditions.

Diagnostic yield of bacteriological tests and predictors of severe outcome in adult patients with COVID-19 presenting to the emergency department

BACKGROUND

Guidelines recommend maximal efforts to obtain blood and sputum cultures in patients with COVID-19, as bacterial coinfection is associated with worse outcomes. The aim of this study was to evaluate the yield of bacteriological tests, including blood and sputum cultures, and the association of multiple biomarkers and the Pneumonia Severity Index (PSI) with clinical and microbiological outcomes in patients with COVID-19 presenting to the emergency department (ED).

METHODS

This is a substudy of a large observational cohort study (PredictED study). The PredictED included adult patients from whom a blood culture was drawn at the ED of Haga Teaching Hospital, The Netherlands. For this substudy, all patients who tested positive for SARS-CoV-2 by PCR in March and April 2020 were included. The primary outcome was the incidence of bacterial coinfection. We used logistic regression analysis for associations of procalcitonin, C reactive protein (CRP), ferritin, lymphocyte count and PSI score with a severe disease course, defined as intensive care unit admission and/or 30-day mortality. The area under the receiver operating characteristics curve (AUC) quantified the discriminatory performance.

RESULTS

We included 142 SARS-CoV-2 positive patients. On presentation, the median duration of symptoms was 8 days. 41 (29%) patients had a severe disease course and 24 (17%) died within 30 days. The incidence of bacterial coinfection was 2/142 (1.4%). None of the blood cultures showed pathogen growth while 6.3% was contaminated. The AUCs for predicting severe disease were 0.76 (95% CI 0.68 to 0.84), 0.70 (0.61 to 0.79), 0.62 (0.51 to 0.74), 0.62 (0.51 to 0.72) and 0.72 (0.63 to 0.81) for procalcitonin, CRP, ferritin, lymphocyte count and PSI score, respectively.

CONCLUSION

Blood cultures appear to have limited value while procalcitonin and the PSI appear to be promising tools in helping physicians identify patients at risk for severe disease course in COVID-19 at presentation to the ED.

Clinical and microbial spectrum of community-acquired pneumonia in children of north India

We compared the clinical, radiological and microbial profile in children suffering from community-acquired pneumonia in rural populations of north India. A total of 125 such children were divided into two age groups of 2-12 months (Group A) and 13-60 months (Group B). After taking a history and clinical examination, routine investigations including full blood count, blood, urine, and nasopharyngeal swab culture and radiology were performed. Multiplex polymerase chain reaction for Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydia pneumoniae and Haemophilus influenzae was carried out. Failure to eat or drink was more common (40.9%) in Group A, than Group B (18.7%). Lung consolidation was more common in Group B. Blood and urine culture were found to be more positive in Group A while combined nasopharyngeal culture and multiplex polymerase chain reaction favoured more bacterial growth in Group B.

ATS Core Curriculum 2020. Adult Pulmonary Medicine

The American Thoracic Society Core Curriculum updates clinicians annually in adult and pediatric pulmonary disease, medical critical care, and sleep medicine in a 3- to 4-year recurring cycle of topics. The topics of the 2020 Pulmonary Core Curriculum include pulmonary vascular disease (submassive pulmonary embolism, chronic thromboembolic pulmonary hypertension, and pulmonary hypertension) and pulmonary infections (community-acquired pneumonia, pulmonary nontuberculous mycobacteria, opportunistic infections in immunocompromised hosts, and coronavirus disease [COVID-19]).

Performance of pneumococcal urinary antigen test in patients with community-onset pneumonia: a propensity score-matching study

BACKGROUND/AIMS

Although pneumococcal urinary antigen tests (PUATs) have universally been used for the diagnosis of pneumococcal pneumonia, data on the efficacy of these exams are limited. The objective of our study was to investigate the clinical impact of the PUAT in patients with community-onset pneumonia (CO-pneumonia).

METHODS

We conducted a retrospective cohort study of patients diagnosed with CO-pneumonia. Patients were classified according to their PUAT results and were matched using the propensity score-matching method. The primary outcome was 30-day mortality.

RESULTS

A total of 1,257 patients were identified and 163 (13.0%) demonstrated positive PUAT results. The sensitivity and specificity values of PUAT for overall pneumococcal pneumonia were 56.5% and 91.4%, respectively. In the full cohort, there were no significant differences in 30-day mortality between the two groups (6.1% in the positive PUAT group vs. 8.2% in the negative PUAT group, p = 0.357). However, in the propensity-matched cohort, the 30-day mortality rates were lower in the positive PUAT group (5.6% vs. 17.4%, p = 0.001). With respect to secondary outcomes, the proportion of patients with potentially drug-resistant pathogens, changes in antibiotics, and failure rates of initial antibiotic therapy were significantly lower in the positive PUAT group than in the negative PUAT group of the propensity-matched cohort.

CONCLUSION

We found that the sensitivity of the index test was low and specificity was high in this clinical setting. And our findings suggest that positive PUAT results may be associated with favorable clinical outcomes in patients with CO-pneumonia.

Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America

Background: This document provides evidence-based clinical practice guidelines on the management of adult patients with community-acquired pneumonia.

Methods: A multidisciplinary panel conducted pragmatic systematic reviews of the relevant research and applied Grading of Recommendations, Assessment, Development, and Evaluation methodology for clinical recommendations.

Results: The panel addressed 16 specific areas for recommendations spanning questions of diagnostic testing, determination of site of care, selection of initial empiric antibiotic therapy, and subsequent management decisions. Although some recommendations remain unchanged from the 2007 guideline, the availability of results from new therapeutic trials and epidemiological investigations led to revised recommendations for empiric treatment strategies and additional management decisions.

Conclusions: The panel formulated and provided the rationale for recommendations on selected diagnostic and treatment strategies for adult patients with community-acquired pneumonia.

Cost-Effectiveness Of Culture-Based Versus Empirical Antibiotic Treatment For Hospitalized Adults With Community-Acquired Pneumonia In Indonesia: A Real-World Patient-Database Study

OBJECTIVE

This study analyzes the cost-effectiveness of culture-based treatment (CBT) versus empirical treatment (ET) as a guide to antibiotic selection and use in hospitalized patients with community-acquired pneumonia (CAP).

PATIENTS AND METHODS

A model was developed from the individual patient data of adults with CAP hospitalized at an academic hospital in Indonesia between 2014 and 2017 (ICD-10 J.18x). The directed antibiotic was assessed based on microbiological culture results in terms of the impact on hospital costs and life expectancy (LE). We conducted subgroup analyses for implementing CBT and ET in adults under 60 years, elderly patients (≥ 60 years), moderate-severe CAP (PSI class III-V) cases, and ICU patients. The model was designed with a lifetime horizon and adjusted patients' ages to the average LE of the Indonesian population with a 3% discount each for cost and LE. We applied a sensitivity analyses on 1,000 simulation cohorts to examine the economic acceptability of CBT in practice. Willingness to pay (WTP) was defined as 1 or 3 times the Indonesian GDP per capita (US$ 3,570).

RESULTS

CBT would effectively increase the patients' LE and be cost-saving (dominant) as well. The ET group's hospitalization cost had the greatest influence on economic outcomes. Subgroup analyses showed that CBT's dominance remained for Indonesian patients aged under 60 years or older, patients with moderate-severe CAP, and patients in the ICU. Acceptability rates of CBT over ET were 74.9% for 1xWTP and 82.8% for 3xWTP in the base case.

CONCLUSION

Both sputum and blood cultures provide advantages for cost-saving and LE gains for hospitalized patients with CAP. CBT is cost-effective in patients all ages, PSI class III or above patients, and ICU patients.

Rate and Predictors of Bacteremia in Afebrile Community-Acquired Pneumonia

BACKGROUND

Although blood cultures (BCs) are the "gold standard" for detecting bacteremia, the utility of BCs in patients with community-acquired pneumonia (CAP) is controversial. This study describes the proportion of patients with CAP and afebrile bacteremia and identifies the clinical characteristics predicting the necessity for BCs in patients who are afebrile.

METHODS

Bacteremia rates were determined in 4,349 patients with CAP enrolled in the multinational cohort study The Competence Network of Community-Acquired Pneumonia (CAPNETZ) and stratified by presence of fever at first patient contact. Independent predictors of bacteremia in patients who were afebrile were determined using logistic regression analysis.

RESULTS

Bacteremic pneumonia was present in 190 of 2,116 patients who were febrile (8.9%), 101 of 2,149 patients who were afebrile (4.7%), and one of 23 patients with hypothermia (4.3%). Bacteremia rates increased with the CURB-65 score from 3.5% in patients with CURB-65 score of 0 to 17.1% in patients with CURB-65 score of 4. Patients with afebrile bacteremia exhibited the highest 28-day mortality rate (9.9%). Positive pneumococcal urinary antigen test (adjusted OR [AOR], 4.6; 95% CI, 2.6-8.2), C-reactive protein level > 200 mg/L (AOR, 3.1; 95% CI, 1.9-5.2), and BUN level ≥ 30 mg/dL (AOR, 3.1; 95% CI, 1.9-5.3) were independent positive predictors, and antibiotic pretreatment (AOR, 0.3; 95% CI, 0.1-0.6) was an independent negative predictor of bacteremia in patients who were afebrile.

CONCLUSIONS

A relevant proportion of patients with bacteremic CAP was afebrile. These patients had an increased mortality rate compared with patients with febrile bacteremia or nonbacteremic pneumonia. Therefore, the relevance of fever as an indicator for BC necessity merits reconsideration.

Pneumococcal and Legionella Urinary Antigen Tests in Community-acquired Pneumonia: Prospective Evaluation of Indications for Testing

BACKGROUND

Adult, community-acquired pneumonia (CAP) guidelines from the Infectious Diseases Society of America (IDSA) and American Thoracic Society (ATS) include indications for urinary antigen tests (UATs) for Streptococcus pneumoniae (SP) and Legionella pneumophila (LP). These recommendations were based on expert opinions and have not been rigorously evaluated.

METHODS

We used data from a multicenter, prospective, surveillance study of adults hospitalized with CAP to evaluate the sensitivity and specificity of the IDSA/ATS UAT indications for identifying patients who test positive. SP and LP UATs were completed on all included patients. Separate analyses were completed for SP and LP, using 2-by-2 contingency tables, comparing the IDSA/ATS indications (UAT recommended vs not recommended) and UAT results (positive vs negative). Additionally, logistic regression was used to evaluate the association of each individual criterion in the IDSA/ATS indications with positive UAT results.

RESULTS

Among 1941 patients, UATs were positive for SP in 81 (4.2%) and for LP in 32 (1.6%). IDSA/ATS indications had 61% sensitivity (95% confidence interval [CI] 49-71%) and 39% specificity (95% CI 37-41%) for SP, and 63% sensitivity (95% CI 44-79%) and 35% specificity (95% CI 33-37%) for LP. No clinical characteristics were strongly associated with positive SP UATs, while features associated with positive LP UATs were hyponatremia, fever, diarrhea, and recent travel.

CONCLUSIONS

Recommended indications for SP and LP urinary antigen testing in the IDSA/ATS CAP guidelines have poor sensitivity and specificity for identifying patients with positive tests; future CAP guidelines should consider other strategies for determining which patients should undergo urinary antigen testing.

Blood culture utilization at an academic hospital: Addressing a gap in benchmarking

OBJECTIVE

To describe the pattern of blood culture utilization in an academic university hospital setting.

DESIGN

Retrospective cohort study.

SETTING

A 789-bed tertiary-care university hospital that processes 40,000+blood cultures annually.

METHODS

We analyzed blood cultures collected from adult inpatients at the Hospital of the University of Pennsylvania between July 1, 2014, and June 30, 2015. Descriptive statistics and regression models were used to analyze patterns of blood culture utilization: frequency of blood cultures, use of repeat cultures following a true-positive culture, and number of sets drawn per day.

RESULTS

In total, 38,939 blood culture sets were drawn during 126,537 patient days (incidence rate, 307.7 sets per 1,000 patient days). The median number of blood culture sets drawn per hospital encounter was 2 (range, 1-76 sets). The median interval between blood cultures was 2 days (range, 1-71 days). Oncology services and cultures with gram-positive cocci were significantly associated with greater odds of having repeat blood cultures drawn the following day. Emergency services had the highest rate of drawing single blood-culture sets (16.9%), while oncology services had the highest frequency of drawing ≥5 blood culture sets within 24 hours (0.91%). Approximately 10% of encounters had at least 1 true-positive culture, and 89.2% of those encounters had repeat blood cultures drawn. The relative risk of a patient having repeat blood cultures was lower for those in emergency, surgery, and oncology services than for those in general medicine.

CONCLUSIONS

Ordering practices differed by service and culture results. Analyzing blood culture utilization can contribute to the development of guidelines and benchmarks for appropriate usage.

Guideline for Antibiotic Use in Adults with Community-acquired Pneumonia

Community-acquired pneumonia is common and important infectious disease in adults. This work represents an update to 2009 treatment guideline for community-acquired pneumonia in Korea. The present clinical practice guideline provides revised recommendations on the appropriate diagnosis, treatment, and prevention of community-acquired pneumonia in adults aged 19 years or older, taking into account the current situation regarding community-acquired pneumonia in Korea. This guideline may help reduce the difference in the level of treatment between medical institutions and medical staff, and enable efficient treatment. It may also reduce antibiotic resistance by preventing antibiotic misuse against acute lower respiratory tract infection in Korea.

Top Questions in Uncomplicated, Non-Staphylococcus aureus Bacteremia

The Infectious Diseases Society of America infection-specific guidelines provide limited guidance on the management of focal infections complicated by secondary bacteremias. We address the following 3 commonly encountered questions and management considerations regarding uncomplicated bacteremia not due to Staphylococcus aureus: the role and choice of oral antibiotics focusing on oral beta-lactams, the shortest effective duration of therapy, and the role of repeat blood cultures.

Community-acquired pneumonia requiring hospitalization: rational decision making and interpretation of guidelines

PURPOSE OF REVIEW

This review focuses on the evidence base for guideline recommendations on the diagnosis, the optimal choice, timing and duration of empirical antibiotic therapy, and the use of microbiological tests for patients hospitalized with community-acquired pneumonia (CAP): issues for which guidelines are frequently used as a quick reference. Furthermore, we will discuss possibilities for future research in these topics.

RECENT FINDINGS

Many national and international guideline recommendations, even on critical elements of CAP management, are based on low-to-moderate quality evidence.

SUMMARY

The diagnosis and management of CAP has hardly changed for decades. The recommendation to cover atypical pathogens in all hospitalized CAP patients is based on observational studies only and is challenged by two recent trials. The following years, improved diagnostic testing, radiologically by low-dose Computed Tomography or ultrasound and/or microbiologically by point-of-care multiplex PCR, has the potential to largely influence the choice and start of antibiotic therapy in hospitalized CAP patients. Rapid microbiological testing will hopefully improve antibiotic de-escalation or early pathogen-directed therapy, both potent ways of reducing broad-spectrum antibiotic use. Current guideline recommendations on the timing and duration of antibiotic therapy are based on limited evidence, but will be hard to improve.

Limited Utility of Polymerase Chain Reaction in Induced Sputum Specimens for Determining the Causes of Childhood Pneumonia in Resource-Poor Settings: Findings From the Pneumonia Etiology Research for Child Health (PERCH) Study

Background.

Sputum examination can be useful in diagnosing the cause of pneumonia in adults but is less well established in children. We sought to assess the diagnostic utility of polymerase chain reaction (PCR) for detection of respiratory viruses and bacteria in induced sputum (IS) specimens from children hospitalized with severe or very severe pneumonia.

Methods.

Among children aged 1–59 months, we compared organism detection by multiplex PCR in IS and nasopharyngeal/oropharyngeal (NP/OP) specimens. To assess whether organism presence or density in IS specimens was associated with chest radiographic evidence of pneumonia (radiographic pneumonia), we compared prevalence and density in IS specimens from children with radiographic pneumonia and children with suspected pneumonia but without chest radiographic changes or clinical or laboratory findings suggestive of pneumonia (nonpneumonia group).

Results.

Among 4232 cases with World Health Organization–defined severe or very severe pneumonia, we identified 1935 (45.7%) with radiographic pneumonia and 573 (13.5%) with nonpneumonia. The organism detection yield was marginally improved with IS specimens (96.2% vs 92.4% for NP/OP specimens for all viruses combined [P = .41]; 96.9% vs 93.3% for all bacteria combined [P = .01]). After accounting for presence in NP/OP specimens, no organism was detected more frequently in the IS specimens from the radiographic pneumonia compared with the nonpneumonia cases. Among high-quality IS specimens, there were no statistically significant differences in organism density, except with cytomegalovirus, for which there was a higher quantity in the IS specimens from cases with radiographic pneumonia compared with the nonpneumonia cases (median cycle threshold value, 27.9 vs 28.5, respectively; P = .01).

Conclusions.

Using advanced molecular methods with IS specimens provided little additional diagnostic information beyond that obtained with NP/OP swab specimens.

Pediatric Community-Acquired Pneumonia in the United States: Changing Epidemiology, Diagnostic and Therapeutic Challenges, and Areas for Future Research

Community-acquired pneumonia (CAP) is one of the most common serious infections in childhood. This review focuses on pediatric CAP in the United States and other industrialized nations, specifically highlighting the changing epidemiology of CAP, diagnostic and therapeutic challenges, and areas for further research.

Diagnosis and treatment of community-acquired pneumonia in adults: 2016 clinical practice guidelines by the Chinese Thoracic Society, Chinese Medical Association

Community‐acquired pneumonia (CAP) in adults is an infectious disease with high morbidity in China and the rest of the world. With the changing pattern in the etiological profile of CAP and advances in medical techniques in diagnosis and treatment over time, Chinese Thoracic Society of Chinese Medical Association updated its CAP guideline in 2016 to address the standard management of CAP in Chinese adults. Extensive and comprehensive literature search was made to collect the data and evidence for experts to review and evaluate the level of evidence. Corresponding recommendations are provided appropriately based on the level of evidence. This updated guideline covers comprehensive topics on CAP, including aetiology, antimicrobial resistance profile, diagnosis, empirical and targeted treatments, adjunctive and supportive therapies, as well as prophylaxis. The recommendations may help clinicians manage CAP patients more effectively and efficiently. CAP in pediatric patients and immunocompromised adults is beyond the scope of this guideline. This guideline is only applicable for the immunocompetent CAP patients aged 18 years and older. The recommendations on selection of antimicrobial agents and the dosing regimens are not mandatory. The clinicians are recommended to prescribe and adjust antimicrobial therapies primarily based on their local etiological profile and results of susceptibility testing, with reference to this guideline.

Utility of Blood Culture Among Children Hospitalized With Community-Acquired Pneumonia

BACKGROUND AND OBJECTIVES

National guidelines recommend blood cultures for children hospitalized with presumed bacterial community-acquired pneumonia (CAP) that is moderate or severe. We sought to determine the prevalence of bacteremia and characterize the microbiology and penicillin-susceptibility patterns of positive blood culture results among children hospitalized with CAP.

METHODS

We conducted a cross-sectional study of children hospitalized with CAP in 6 children's hospitals from 2007 to 2011. We included children 3 months to 18 years of age with discharge diagnosis codes for CAP using a previously validated algorithm. We excluded children with complex chronic conditions. We reviewed microbiologic data and classified positive blood culture detections as pathogens or contaminants. Antibiotic-susceptibility patterns were assessed for all pathogens.

RESULTS

A total of 7509 children hospitalized with CAP were included over the 5-year study period. Overall, 34% of the children hospitalized with CAP had a blood culture performed; 65 (2.5% of patients with blood cultures; 95% confidence interval [CI]: 2.0%-3.2%) grew a pathogen. Streptococcus pneumoniae accounted for 78% of all detected pathogens. Among detected pathogens, 50 (82%) were susceptible to penicillin. Eleven children demonstrated growth of an organism nonsusceptible to penicillin, representing 0.43% (95% CI: 0.23%-0.77%) of children with blood cultures obtained and 0.15% (95% CI: 0.08%-0.26%) of all children hospitalized with CAP.

CONCLUSIONS

Among children without comorbidities hospitalized with CAP in a non-ICU setting, the rate of bacteremia was low, and isolated pathogens were usually susceptible to penicillin. Blood cultures may not be needed for most children hospitalized with CAP.

Transcriptomic Biomarkers to Discriminate Bacterial from Nonbacterial Infection in Adults Hospitalized with Respiratory Illness

Lower respiratory tract infection (LRTI) commonly causes hospitalization in adults. Because bacterial diagnostic tests are not accurate, antibiotics are frequently prescribed. Peripheral blood gene expression to identify subjects with bacterial infection is a promising strategy. We evaluated whole blood profiling using RNASeq to discriminate infectious agents in adults with microbiologically defined LRTI. Hospitalized adults with LRTI symptoms were recruited. Clinical data and blood was collected, and comprehensive microbiologic testing performed. Gene expression was measured using RNASeq and qPCR. Genes discriminatory for bacterial infection were identified using the Bonferroni-corrected Wilcoxon test. Constrained logistic models to predict bacterial infection were fit using screened LASSO. We enrolled 94 subjects who were microbiologically classified; 53 as “non-bacterial” and 41 as “bacterial”. RNAseq and qPCR confirmed significant differences in mean expression for 10 genes previously identified as discriminatory for bacterial LRTI. A novel dimension reduction strategy selected three pathways (lymphocyte, α-linoleic acid metabolism, IGF regulation) including eleven genes as optimal markers for discriminating bacterial infection (naïve AUC = 0.94; nested CV-AUC = 0.86). Using these genes, we constructed a classifier for bacterial LRTI with 90% (79% CV) sensitivity and 83% (76% CV) specificity. This novel, pathway-based gene set displays promise as a method to distinguish bacterial from nonbacterial LRTI.

Controversies in diagnosis and management of community-acquired pneumonia

Community-acquired pneumonia (CAP) is a common condition; however, it appears to be overdiagnosed. Diagnosing CAP too frequently may be adding to the problems of overuse of antibiotics, such as bacterial resistance in the community and greater costs and complications in individuals. Data support that most patients with non-severe CAP can be treated for 3-5 days; however, most patients with CAP are receiving much longer courses of therapy. Macrolides such as azithromycin have the potential to prolong the QT interval, although large population studies show that this does not appear to result in excess cardiac mortality. CAP is associated with an increase in a variety of cardiac complications, most notably infarctions and worsening cardiac failure, so clinicians should be vigilant for signs and symptoms of these complications, particularly in patients with a history of ischaemic cardiac disease or the presence of cardiac risk factors. Cardiac risk factors should be assessed and managed in patients with CAP over 40 years of age, although there are yet to be data to show that this approach reduces deaths. Corticosteroids may have a slight effect on reducing deaths in patients with severe CAP, but this must be balanced against the significant potential for side effects.

Influence of Antibiotics on the Detection of Bacteria by Culture-Based and Culture-Independent Diagnostic Tests in Patients Hospitalized With Community-Acquired Pneumonia

BACKGROUND

Specimens collected after antibiotic exposure may reduce culture-based bacterial detections. The impact on culture-independent diagnostic tests is unclear. We assessed the effect of antibiotic exposure on both of these test results among patients hospitalized with community-acquired pneumonia (CAP).

METHODS

Culture-based bacterial testing included blood cultures and high-quality sputum or endotracheal tube (ET) aspirates; culture-independent testing included urinary antigen testing (adults) for Streptococcus pneumoniae and Legionella pneumophila and polymerase chain reaction (PCR) on nasopharyngeal and oropharyngeal (NP/OP) swabs for Mycoplasma pneumoniae and Chlamydia pneumoniae. The proportion of bacterial detections was compared between specimens collected before and after either any antibiotic exposure (prehospital and/or inpatient) or only prehospital antibiotics and increasing time after initiation of inpatient antibiotics.

RESULTS

Of 4678 CAP patients, 4383 (94%) received antibiotics: 3712 (85%) only inpatient, 642 (15%) both inpatient and prehospital, and 29 (<1%) only prehospital. There were more bacterial detections in specimens collected before antibiotics for blood cultures (5.2% vs 2.6%; P < .01) and sputum/ET cultures (50.0% vs 26.8%; P < .01) but not urine antigen (7.0% vs 5.7%; P = .53) or NP/OP PCR (6.7% vs 5.4%; P = .31). For all diagnostic testing, bacterial detections declined with increasing time between inpatient antibiotic administration and specimen collection.

CONCLUSIONS

Bacteria were less frequently detected in culture-based tests collected after antibiotics and in culture-independent tests that had longer intervals between antibiotic exposure and specimen collection. Bacterial yield could improve if specimens were collected promptly, preferably before antibiotics, providing data for improved antibiotic selection.

Evaluation of a Commercial Multiplex PCR Assay for Detection of Pathogen DNA in Blood from Patients with Suspected Sepsis

The Magicplex Sepsis Real-time Test (MST) is a commercial multiplex PCR that can detect more than 90 different pathogens in blood, with an analysis time of six hours. The aim of the present study was to evaluate this method for the detection of bloodstream infection (BSI). An EDTA whole blood sample for MST was collected together with blood cultures (BC) from patients with suspected sepsis at the Emergency Department of a university hospital. Among 696 study patients, 322 (46%) patients were positive with at least one method; 128 (18%) were BC positive and 268 (38%) were MST positive. Considering BC to be the gold standard, MST had an overall sensitivity of 47%, specificity of 66%, positive predictive value (PPV) of 23%, and a negative predictive value of 87%. Among the MST positive samples with a negative BC, coagulase-negative staphylococci (CoNS) and species that rarely cause community-acquired BSI were frequently noted. However, the quantification cycle (Cq) values of the MST+/BC- results were often high. We thus hypothesized that the performance of the MST test could be improved if the Cq cut-off level was adjusted downwards. With a lower Cq cut-off value, i.e. 6.0 for Staphylococcus species and 9.0 for all other species, the number of MST positive cases decreased to 83 (12%) and the overall sensitivity decreased to 38%. However, the PPV increased to 59% and the specificity increased to 96%, as many MST positive results for CoNS and bacteria that rarely cause community-acquired BSI turned MST negative. In conclusion, our study shows that with a lower Cq cut-off value, the MST will detect less contaminants and findings with unclear relevance, but to the cost of a lower sensitivity. Consequently, we consider that a positive MST results with a Cq value above the adjusted cut-off should be interpreted with caution, as the result might be clinically irrelevant. In a correspondent way, quantitative results could probably be useful in the interpretation of positive results from other molecular assays for the detection of BSI.

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.

Bacteraemia predictive factors among general medical inpatients: a retrospective cross-sectional survey in a Japanese university hospital

OBJECTIVES

The precise criteria for obtaining blood cultures have not been established; they depend on the physician's judgement. We examined clinical parameters to determine predictive factors of bacteraemia and the need for blood cultures among general medical inpatients.

DESIGN

A retrospective cross-sectional survey.

SETTING

A Japanese university hospital.

PARTICIPANTS

All general inpatients who had blood cultures taken from 1 January 2011 to 31 December 2012.

MAIN MEASURES

Clinical information at or just before blood culture sampling was extracted from medical charts. Factors potentially predictive of bacteraemia were analysed using Fisher's exact test, followed by multivariable logistic regression model analysis.

MAIN RESULTS

A total of 200 patients (male: female=119:81, 64.3±19.1 years old) comprised this study; 57 (28.5%) had positive blood culture results. Multivariable logistic regression analysis revealed that age >60 years (OR=2.75, 95% CI 1.23 to 6.48, p=0.015), female sex (OR=2.21, 95% CI 1.07 to 4.67, p=0.038), pulse rate >90 bpm (OR=5.18, 95% CI 2.25 to 12.48, p<0.001) and neutrophil percentage >80% (OR=3.61, 95% CI 1.71 to 8.00, p=0.001) were independent risk factors for positive blood culture results. The area under the receiver operating characteristic curve analysis of this model was 0.796.

CONCLUSIONS

Our results emphasise the importance of taking blood cultures if the pulse rate is >90 bpm, in elderly patients and in women, and for ordering a differential white cell count.

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.

Limited utility of blood cultures in the management of febrile outpatient kidney transplant recipients

BACKGROUND/PURPOSE

Blood cultures for patients suspected of having bacteremia are standard practice, although several studies demonstrate that blood cultures have limited utility because of a low true-positive rate and infrequent resultant changes in antibiotic treatment. However, most reports exclude immunocompromised patients such as transplant recipients. We assessed the utility of blood cultures in transplant recipients hospitalized for community-acquired infections and evaluated clinical characteristics to predict bacteremia.

METHODS

This retrospective study included 136 febrile cases in 97 kidney transplant recipients admitted to our hospital for whom blood cultures were performed between February 2001 and March 2013.

RESULTS

Among the 136 cases, blood cultures were positive, contaminated, and negative in seven (5.1%) cases, 12 (8.8%) cases, and 117 cases (86.1%), respectively. All bacteria detected in the seven cases were sensitive to the initial empirical antibiotics. Antibiotic treatment was changed based on the blood culture results only in one case for which the coverage was narrowed. The white blood cell count and C-reactive protein level were significantly higher in the patients with bacteremia. The predictive model based on these two factors successfully identified the high-risk group with a sensitivity and specificity of 86% and 91%, respectively.

CONCLUSION

Among the outpatient kidney transplant recipients, positive blood cultures were uncommon and scarcely affected antibiotic therapy, especially in patients with upper respiratory tract or urinary tract infections. Therefore, it may be reasonable to perform blood cultures only for patients with marked leukocytosis and high C-reactive protein level, even among transplant recipients.

Predictors of Bacteraemia in Patients with Suspected Community-Acquired Pneumonia

Introduction

The diagnostic yield of blood cultures is limited in patients with community-acquired pneumonia (CAP). Yet, positive blood culture results provide important information for antibiotic treatment and for monitoring epidemiologic trends. We investigated the potential of clinical predictors to improve the cost-benefit ratio of obtaining blood cultures.

Methods

Data from two prospective cohort studies of adults with suspected CAP, admitted to non-ICU wards, were combined. Two models were created, one using readily available parameters and one additionally including laboratory parameters.

Results

3,786 patients were included (2,626 (69%) with X-ray confirmed CAP). Blood cultures were obtained from 2,977 (79%) patients (and from 2,107 (80%) with X-ray confirmed CAP). 266 (8.9%) of the patients with a blood culture had bacteraemia. Clinical predictors of bacteraemia were absence of pre-admission antibiotic treatment, pleuritic pain, gastro-intestinal symptoms, tachycardia, tachypnea, hypotension and absence of hypoxia. After including laboratory results in the model, younger age, C-reactive protein, leukocytosis or leukopenia, low thrombocyte count, low sodium level, elevated urea and elevated arterial pH were added, while gastro-intestinal symptoms and hypotension were no longer significant. The area under the receiver operating characteristics curve was 0.66 (95% confidence interval 0.63–0.70) for the first model and 0.76 (95% confidence interval 0.73–0.79) for the second model.

Conclusion

In conclusion, in patients hospitalized with CAP, bacteraemia was moderately predictable using clinical parameters only. We recommend against the use of a risk prediction model for the decision to obtain blood cultures.

A Retrospective Evaluation of Critical Care Blood Culture Yield - Do Support Services Contribute to the "Weekend Effect"?

Background

The “weekend effect” describes an increase in adverse outcomes for patients admitted at the weekend. Critical care units have moved to higher intensity working patterns to address this with some improved outcomes. However, support services have persisted with traditional working patterns. Blood cultures are an essential diagnostic tool for patients with sepsis but yield is dependent on sampling technique and processing. We therefore used blood culture yield as a surrogate for the quality of support service provision.

We hypothesized that blood culture yields would be lower over the weekend as a consequence of reduced support services.

Methods

We performed a retrospective observational study examining 1575 blood culture samples in a university hospital critical care unit over a one-year period.

Results

Patients with positive cultures had, on average, higher APACHE II scores (p = 0.015), longer durations of stay (p = 0.03), required more renal replacement therapy (p<0.001) and had higher mortality (p = 0.024). Blood culture yield decreased with repeated sampling with an increased proportion of contaminants. Blood cultures were 26.7% less likely to be positive if taken at the weekend (p = 0.0402). This effect size is the equivalent to the impact of sampling before and after antibiotic administration.

Conclusions

Our study demonstrates that blood culture yield is lower at the weekend. This is likely caused by delays or errors in incubation and processing, reflecting the reduced provision of support services at the weekend. Reorganization of services to address the “weekend effect” should acknowledge the interdependent nature of healthcare service delivery.

Improving outcomes from community-acquired pneumonia

PURPOSE OF REVIEW

We are entering into a new era of healthcare wherein patient outcomes are increasingly being publicly reported, not just by institution, but by individual clinicians. This review focuses on the issue of quality of care of patients with community-acquired pneumonia (CAP), in particular the choice of outcome, quality of data needed and recommendations of the current bundle of care suggested by the available literature as delivering the best chance of favourable outcomes for patients.

RECENT FINDINGS

There is increasing evidence that pneumonia outcomes have improved over the past decade, particularly mortality. However, we have been oversimplistic in setting quality targets and that a bundle of care is required to deliver best outcomes, such as has been shown with the surviving sepsis campaign. Equally, the quality of data available to compare outcomes needs to be significantly improved on what is currently available.

SUMMARY

To achieve best outcomes for their patients, physicians must be actively comparing their outcomes against other institutions and not rely on historical data. A bundle of care that includes rapid administration of antibiotics, use of combination antibiotic therapy including a macrolide and early mobilization is a good starting point.

Validation of sputum Gram stain for treatment of community-acquired pneumonia and healthcare-associated pneumonia: a prospective observational study

BACKGROUND

The usefulness of sputum Gram stain in patients with community-acquired pneumonia (CAP) is controversial. There has been no study to evaluate the diagnostic value of this method in patients with healthcare-associated pneumonia (HCAP). The purpose of this study was to evaluate the usefulness of sputum Gram stain in etiological diagnosis and pathogen-targeted antibiotic treatment of CAP and HCAP.

METHODS

We conducted a prospective observational study on hospitalized patients with pneumonia admitted to our hospital from August 2010 to July 2012. Before administering antibiotics on admission, Gram stain was performed and examined by trained physicians immediately after sputum samples were obtained. We analyzed the quality of sputum samples and the diagnostic performance of Gram stain. We also compared pathogen-targeted antibiotic treatment guided by sputum Gram stain with empirical treatment.

RESULTS

Of 670 patients with pneumonia, 328 were CAP and 342 were HCAP. Sputum samples were obtained from 591 patients, of these 478 samples were good quality. The sensitivity and specificity of sputum Gram stain were 62.5% and 91.5% for Streptococcus pneumoniae, 60.9% and 95.1% for Haemophilus influenzae, 68.2% and 96.1% for Moraxella catarrhalis, 39.5% and 98.2% for Klebsiella pneumoniae, 22.2% and 99.8% for Pseudomonas aeruginosa, 9.1% and 100% for Staphylococcus aureus. The diagnostic yield decreased in patients who had received antibiotics or patients with suspected aspiration pneumonia. Pathogen-targeted treatment provided similar efficacy with a decrease in adverse events compared to empirical treatment.

CONCLUSIONS

Sputum Gram stain is highly specific for the etiologic diagnosis and useful in guiding pathogen-targeted antibiotic treatment of CAP and HCAP.

[Which samples to obtain in the emergency department for the microbiological diagnosis of community-acquired pneumonia in the immunocompetent patient?]

Current diagnostic methods allow microbial identification in 50% of patients admitted with severe community-acquired pneumonia (CAP). Guidelines derived from epidemiological data help physicians to start empirical antimicrobial therapy. Definitive microbial diagnosis is useful to guide further pathogen-directed therapy. Blood cultures, cultures of respiratory specimens and urine antigen tests are recommended to determine the causative bacterial pathogen. Positive blood cultures range from 15 to 25% of CAP patients according to severity. Whether sputum specimens represent or not lower respiratory secretions determines its accuracy in CAP microbial diagnosis. In intubated patients, endotracheal aspirates are often of interest. Detection of positive pneumococcal or legionella urinary antigen is often associated with CAP severity. The sensitivity of this test is not decreased in patients who have received antibiotics prior to sampling. Viral pneumonia account for 10 to 40% of severe CAP. Nasal swabs are recommended for influenza identification using polymerase chain reaction (PCR) in order to deliver oseltamivir treatment. In the emergency department, atypical pneumonia serology is less useful than respiratory specimens obtained using fiberoptic bronchoscopy. Serum PCR to diagnose bacterial CAP is not superior to the other usual methods.