Prolonged exposure to lung-derived cytokines is associated with activation of microglia in patients with COVID-19.

BACKGROUNDSurvivors of pneumonia, including SARS-CoV-2 pneumonia, are at increased risk for cognitive dysfunction and dementia. In rodent models, cognitive dysfunction following pneumonia has been linked to the systemic release of lung-derived pro-inflammatory cytokines. Microglia are poised to respond to inflammatory signals from the circulation, and their dysfunction has been linked to cognitive impairment in murine models of dementia and in humans.METHODSWe measured levels of 55 cytokines and chemokines in bronchoalveolar lavage fluid and plasma from 341 patients with respiratory failure and 13 healthy controls, including 93 unvaccinated patients with COVID-19 and 203 patients with other causes of pneumonia. We used flow cytometry to sort neuroimmune cells from postmortem brain tissue from 5 patients who died from COVID-19 and 3 patients who died from other causes for single-cell RNA-sequencing.RESULTSMicroglia from patients with COVID-19 exhibited a transcriptomic signature suggestive of their activation by circulating pro-inflammatory cytokines. Peak levels of pro-inflammatory cytokines were similar in patients with pneumonia irrespective of etiology, but cumulative cytokine exposure was higher in patients with COVID-19. Treatment with corticosteroids reduced expression of COVID-19-specific cytokines.CONCLUSIONProlonged lung inflammation results in sustained elevations in circulating cytokines in patients with SARS-CoV-2 pneumonia compared with those with pneumonia secondary to other pathogens. Microglia from patients with COVID-19 exhibit transcriptional responses to inflammatory cytokines. These findings support data from rodent models causally linking systemic inflammation with cognitive dysfunction in pneumonia and support further investigation into the role of microglia in pneumonia-related cognitive dysfunction.FUNDINGSCRIPT U19AI135964, UL1TR001422, P01AG049665, P01HL154998, R01HL149883, R01LM013337, R01HL153122, R01HL147290, R01HL147575, R01HL158139, R01ES034350, R01ES027574, I01CX001777, U01TR003528, R21AG075423, T32AG020506, F31AG071225, T32HL076139.

Individual meropenem epithelial lining fluid and plasma PK/PD target attainment.

It is unclear whether plasma is a reliable surrogate for target attainment in the epithelial lining fluid (ELF). The objective of this study was to characterize meropenem target attainment in plasma and ELF using prospective samples. The first 24-hour T>MIC was evaluated vs 1xMIC and 4xMIC targets at the patient (i.e., fixed MIC of 2 mg/L) and population [i.e., cumulative fraction of response (CFR) according to EUCAST MIC distributions] levels for both plasma and ELF. Among 65 patients receiving ≥24 hours of treatment, 40% of patients failed to achieve >50% T>4xMIC in plasma and ELF, and 30% of patients who achieved >50% T>4xMIC in plasma had <50% T>4xMIC in ELF. At 1xMIC and 4xMIC targets, 3% and 25% of patients with >95% T>MIC in plasma had <50% T>MIC in ELF, respectively. Those with a CRCL >115 mL/min were less likely to achieve >50%T>4xMIC in ELF (P < 0.025). In the population, CFR for Escherichia coli at 1xMIC and 4xMIC was >97%. For Pseudomonas aeruginosa, CFR was ≥90% in plasma and ranged 80%-85% in ELF at 1xMIC when a loading dose was applied. CFR was reduced in plasma (range: 75%-81%) and ELF (range: 44%-60%) in the absence of a loading dose at 1xMIC. At 4xMIC, CFR for P. aeruginosa was 60%-86% with a loading dose and 18%-62% without a loading dose. We found that plasma overestimated ELF target attainment inup to 30% of meropenem-treated patients, CRCL >115 mL/min decreased target attainment in ELF, and loading doses increased CFR in the population.

Prolonged exposure to lung-derived cytokines is associated with inflammatory activation of microglia in patients with COVID-19.

Neurological impairment is the most common finding in patients with post-acute sequelae of COVID-19. Furthermore, survivors of pneumonia from any cause have an elevated risk of dementia1-4. Dysfunction in microglia, the primary immune cell in the brain, has been linked to cognitive impairment in murine models of dementia and in humans5. Here, we report a transcriptional response in human microglia collected from patients who died following COVID-19 suggestive of their activation by TNF-α and other circulating pro-inflammatory cytokines. Consistent with these findings, the levels of 55 alveolar and plasma cytokines were elevated in a cohort of 341 patients with respiratory failure, including 93 unvaccinated patients with COVID-19 and 203 patients with other causes of pneumonia. While peak levels of pro-inflammatory cytokines were similar in patients with pneumonia irrespective of etiology, cumulative cytokine exposure was higher in patients with COVID-19. Corticosteroid treatment, which has been shown to be beneficial in patients with COVID-196, was associated with lower levels of CXCL10, CCL8, and CCL2-molecules that sustain inflammatory circuits between alveolar macrophages harboring SARS-CoV-2 and activated T cells7. These findings suggest that corticosteroids may break this cycle and decrease systemic exposure to lung-derived cytokines and inflammatory activation of microglia in patients with COVID-19.

An Adjudication Protocol for Severe Pneumonia.

Background: Clinical end points that constitute successful treatment in severe pneumonia are difficult to ascertain and vulnerable to bias. The utility of a protocolized adjudication procedure to determine meaningful end points in severe pneumonia has not been well described. Methods: This was a single-center prospective cohort study of patients with severe pneumonia admitted to the medical intensive care unit. The objective was to develop an adjudication protocol for severe bacterial and/or viral pneumonia. Each episode of pneumonia was independently reviewed by 2 pulmonary and critical care physicians. If a discrepancy occurred between the 2 adjudicators, a third adjudicator reviewed the case. If a discrepancy remained after all 3 adjudications, consensus was achieved through committee review. Results: Evaluation of 784 pneumonia episodes during 593 hospitalizations achieved only 48.1% interobserver agreement between the first 2 adjudicators and 78.8% when agreement was defined as concordance between 2 of 3 adjudicators. Multiple episodes of pneumonia and presence of bacterial/viral coinfection in the initial pneumonia episode were associated with lower interobserver agreement. For an initial episode of bacterial pneumonia, patients with an adjudicated day 7-8 clinical impression of cure (compared with alternative impressions) were more likely to be discharged alive (odds ratio, 6.3; 95% CI, 3.5-11.6). Conclusions: A comprehensive adjudication protocol to identify clinical end points in severe pneumonia resulted in only moderate interobserver agreement. An adjudicated end point of clinical cure by day 7-8 was associated with more favorable hospital discharge dispositions, suggesting that clinical cure by day 7-8 may be a valid end point to use in adjudication protocols.

Machine learning links unresolving secondary pneumonia to mortality in patients with severe pneumonia, including COVID-19.

BACKGROUNDDespite guidelines promoting the prevention and aggressive treatment of ventilator-associated pneumonia (VAP), the importance of VAP as a driver of outcomes in mechanically ventilated patients, including patients with severe COVID-19, remains unclear. We aimed to determine the contribution of unsuccessful treatment of VAP to mortality for patients with severe pneumonia.METHODSWe performed a single-center, prospective cohort study of 585 mechanically ventilated patients with severe pneumonia and respiratory failure, 190 of whom had COVID-19, who underwent at least 1 bronchoalveolar lavage. A panel of intensive care unit (ICU) physicians adjudicated the pneumonia episodes and endpoints on the basis of clinical and microbiological data. Given the relatively long ICU length of stay (LOS) among patients with COVID-19, we developed a machine-learning approach called CarpeDiem, which grouped similar ICU patient-days into clinical states based on electronic health record data.RESULTSCarpeDiem revealed that the long ICU LOS among patients with COVID-19 was attributable to long stays in clinical states characterized primarily by respiratory failure. While VAP was not associated with mortality overall, the mortality rate was higher for patients with 1 episode of unsuccessfully treated VAP compared with those with successfully treated VAP (76.4% versus 17.6%, P < 0.001). For all patients, including those with COVID-19, CarpeDiem demonstrated that unresolving VAP was associated with a transitions to clinical states associated with higher mortality.CONCLUSIONSUnsuccessful treatment of VAP is associated with higher mortality. The relatively long LOS for patients with COVID-19 was primarily due to prolonged respiratory failure, placing them at higher risk of VAP.FUNDINGNational Institute of Allergy and Infectious Diseases (NIAID), NIH grant U19AI135964; National Heart, Lung, and Blood Institute (NHLBI), NIH grants R01HL147575, R01HL149883, R01HL153122, R01HL153312, R01HL154686, R01HL158139, P01HL071643, and P01HL154998; National Heart, Lung, and Blood Institute (NHLBI), NIH training grants T32HL076139 and F32HL162377; National Institute on Aging (NIA), NIH grants K99AG068544, R21AG075423, and P01AG049665; National Library of Medicine (NLM), NIH grant R01LM013337; National Center for Advancing Translational Sciences (NCATS), NIH grant U01TR003528; Veterans Affairs grant I01CX001777; Chicago Biomedical Consortium grant; Northwestern University Dixon Translational Science Award; Simpson Querrey Lung Institute for Translational Science (SQLIFTS); Canning Thoracic Institute of Northwestern Medicine.

Individual target pharmacokinetic/pharmacodynamic attainment rates among meropenem-treated patients admitted to the ICU with hospital-acquired pneumonia.

OBJECTIVES: Critical illness reduces ß-lactam pharmacokinetic/pharmacodynamic (PK/PD) attainment. We sought to quantify PK/PD attainment in patients with hospital-acquired pneumonia. METHODS: Meropenem plasma PK data (n = 70 patients) were modelled, PK/PD attainment rates were calculated for empirical and definitive targets, and between-patient variability was quantified [as a coefficient of variation (CV%)]. RESULTS: Attainment of 100% T>4×MIC was variable for both empirical (CV% = 92) and directed (CV% = 33%) treatment. CONCLUSIONS: Individualization is required to achieve suggested PK/PD targets in critically ill patients.

Association between a rapid diagnostic test to detect methicillin-resistant Staphylococcus Aureus pneumonia and decreased vancomycin use in a medical intensive care unit over a 30-month period.

Vancomycin overuse is common, yet few data are available regarding how to improve stewardship of this antibiotic. We identify an association between use of a PCR assay to rule out MRSA pneumonia and a significant, sustained decrease in average vancomycin days of therapy over a 30-month period.

Circuits between infected macrophages and T cells in SARS-CoV-2 pneumonia.

Some patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) develop severe pneumonia and acute respiratory distress syndrome1 (ARDS). Distinct clinical features in these patients have led to speculation that the immune response to virus in the SARS-CoV-2-infected alveolus differs from that in other types of pneumonia2. Here we investigate SARS-CoV-2 pathobiology by characterizing the immune response in the alveoli of patients infected with the virus. We collected bronchoalveolar lavage fluid samples from 88 patients with SARS-CoV-2-induced respiratory failure and 211 patients with known or suspected pneumonia from other pathogens, and analysed them using flow cytometry and bulk transcriptomic profiling. We performed single-cell RNA sequencing on 10 bronchoalveolar lavage fluid samples collected from patients with severe coronavirus disease 2019 (COVID-19) within 48 h of intubation. In the majority of patients with SARS-CoV-2 infection, the alveolar space was persistently enriched in T cells and monocytes. Bulk and single-cell transcriptomic profiling suggested that SARS-CoV-2 infects alveolar macrophages, which in turn respond by producing T cell chemoattractants. These T cells produce interferon-γ to induce inflammatory cytokine release from alveolar macrophages and further promote T cell activation. Collectively, our results suggest that SARS-CoV-2 causes a slowly unfolding, spatially limited alveolitis in which alveolar macrophages containing SARS-CoV-2 and T cells form a positive feedback loop that drives persistent alveolar inflammation.

Seriously Foolish and Foolishly Serious: The Art and Practice of Clowning in Children's Rehabilitation.

This paper interrogates and reclaims clown practices in children's rehabilitation as 'foolish.' Attempts to legitimize and 'take seriously' clown practices in the health sciences frame the work of clowns as secondary to the 'real' work of medical professionals and diminish the ways clowns support emotional vulnerability and bravery with a willingness to fail and be ridiculous as fundamental to their work. Narrow conceptualizations of clown practices in hospitals as only happy and funny overlook the ways clowns also routinely engage with sadness, despair, discomfort and many other ways of being and doing. Our exploration of clown practices as foolish exposes the ways children's rehabilitation upholds particular neoliberal models of success and invites a re-centring of rehabilitation and health care research and practice towards relationship building, supporting meaningful projects and a continued nurturing of aesthetic and pleasurable ways of being-in-the-world in the present moment as valuable unto themselves.

A multiplex polymerase chain reaction assay for antibiotic stewardship in suspected pneumonia.

BACKGROUND: Multiplexed molecular rapid diagnostic tests (RDTs) may allow for rapid and accurate diagnosis of the microbial etiology of pneumonia. However, little data are available on multiplexed RDTs in pneumonia and their impact on clinical practice. METHODS: This retrospective study analyzed 659 hospitalized patients for microbiological diagnosis of suspected pneumonia. RESULTS: The overall sensitivity of the Unyvero LRT Panel was 85.7% (95% CI 82.3-88.7) and the overall specificity was 98.4% (95% CI 98.2-98.7) with a negative predictive value of 97.9% (95% CI 97.6-98.1). The LRT Panel result predicted no change in antibiotics in 12.4% of cases but antibiotic de-escalation in 65.9% (405/615) of patients, of whom 278/405 (69%) had unnecessary MRSA coverage and 259/405 (64%) had unnecessary P. aeruginosa coverage. INTERPRETATION: In hospitalized adults with suspected pneumonia, use of an RDT on respiratory samples can allow for early adjustment of initial antibiotics, most commonly de-escalation.

PROPHETIC: Prospective Identification of Pneumonia in Hospitalized Patients in the ICU.

BACKGROUND: Pneumonia is the leading infection-related cause of death. The use of simple clinical criteria and contemporary epidemiology to identify patients at high risk of nosocomial pneumonia should enhance prevention efforts and facilitate development of new treatments in clinical trials. RESEARCH QUESTION: What are the clinical criteria and contemporary epidemiology trends that are helpful in the identification of patients at high risk of nosocomial pneumonia? STUDY DESIGN AND METHODS: Within the ICUs of 28 US hospitals, we conducted a prospective cohort study among adults who had been hospitalized >48 hours and were considered high risk for pneumonia (defined as treatment with invasive or noninvasive ventilatory support or high levels of supplemental oxygen). We estimated the proportion of high-risk patients who experienced the development of nosocomial pneumonia. Using multivariable logistic regression, we identified patient characteristics and treatment exposures that are associated with increased risk of pneumonia development during the ICU admission. RESULTS: Between February 6, 2016, and October 7, 2016, 4,613 high-risk patients were enrolled. Among 1,464 high-risk patients (32%) who were treated for possible nosocomial pneumonia, 537 (37%) met the study pneumonia definition. Among high-risk patients, a multivariable logistic model was developed to identify key patient characteristics and treatment exposures that are associated with increased risk of nosocomial pneumonia development (c-statistic, 0.709; 95% CI, 0.686-0.731). Key factors associated with increased odds of nosocomial pneumonia included an admission diagnosis of trauma or cerebrovascular accident, receipt of enteral nutrition, documented aspiration risk, and receipt of systemic antibacterials within the preceding 90 days. INTERPRETATION: Treatment for nosocomial pneumonia is common among patients in the ICU who are receiving high levels of respiratory support, yet more than one-half of patients who are treated do not fulfill standard diagnostic criteria for pneumonia. Application of simple clinical criteria may improve the feasibility of clinical trials of pneumonia prevention and treatment by facilitating prospective identification of patients at highest risk.

Consensus on Language for Advance Informed Consent in Health Care-Associated Pneumonia Clinical Trials Using a Delphi Process.

Importance: Information to be included in advance informed consent forms for health care-associated pneumonia treatment trials remains to be determined. Objective: To identify and determine how to describe information to be included in an advance informed consent form for an early-enrollment noninferiority hospital-acquired and/or ventilator-associated bacterial pneumonia (HABP/VABP) clinical trial. Design, Setting, and Participants: A Delphi consensus process with stakeholders in HABP/VABP clinical trials was conducted using qualitative semistructured telephone interviews from June to August 2016, followed by 2 online surveys, the first from April to May 2017, and the second from September to October 2017. All stakeholders who participated in the interview were invited to participate in the first survey. Stakeholders who participated in the first survey were invited to participate in the second survey. Stakeholders were patients at risk of pneumonia, caregivers, representatives of institutional review boards, investigators, and study coordinators. Main Outcomes and Measures: Description and consensus of information to be included in advance informed consent forms for early enrollment in noninferiority HABP/VABP clinical trials. Results: Suggestions from 52 stakeholders about what key informed consent concepts to include and how to explain them were used to create 3 categories to be included in an advance consent form: (1) reassurances on patient health and treatment, (2) rationale for advance consent and early enrollment, and (3) an explanation of noninferiority. At the end of the Delphi process, at least 80% consensus was reached among the 40 stakeholders who participated in the second online survey on each of the statements to include in the proposed consent text. Throughout the process, however, describing and reaching consensus on statements about noninferiority was more problematic than the other categories. Conclusions and Relevance: The stakeholders endorsed consent language to be used in combination with a strategy for enrolling patients at highest risk for pneumonia before infection onset. Data-driven consent language may help potential participants make informed decisions about their involvement in clinical research and improve enrollment rates, which are necessary to evaluate new treatments and improve patient care. The proposed consent language may be adapted for other trials using an early enrollment strategy and for noninferiority trials.

Alveolitis in severe SARS-CoV-2 pneumonia is driven by self-sustaining circuits between infected alveolar macrophages and T cells.

Some patients infected with Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) develop severe pneumonia and the acute respiratory distress syndrome (ARDS) [1]. Distinct clinical features in these patients have led to speculation that the immune response to virus in the SARS-CoV-2-infected alveolus differs from other types of pneumonia [2]. We collected bronchoalveolar lavage fluid samples from 86 patients with SARS-CoV-2-induced respiratory failure and 252 patients with known or suspected pneumonia from other pathogens and subjected them to flow cytometry and bulk transcriptomic profiling. We performed single cell RNA-Seq in 5 bronchoalveolar lavage fluid samples collected from patients with severe COVID-19 within 48 hours of intubation. In the majority of patients with SARS-CoV-2 infection at the onset of mechanical ventilation, the alveolar space is persistently enriched in alveolar macrophages and T cells without neutrophilia. Bulk and single cell transcriptomic profiling suggest SARS-CoV-2 infects alveolar macrophages that respond by recruiting T cells. These T cells release interferon-gamma to induce inflammatory cytokine release from alveolar macrophages and further promote T cell recruitment. Our results suggest SARS-CoV-2 causes a slowly unfolding, spatially-limited alveolitis in which alveolar macrophages harboring SARS-CoV-2 transcripts and T cells form a positive feedback loop that drives progressive alveolar inflammation. This manuscript is accompanied by an online resource: https://www.nupulmonary.org/covid-19/. ONE SENTENCE SUMMARY: SARS-CoV-2-infected alveolar macrophages form positive feedback loops with T cells in patients with severe COVID-19.

Rapid Detection of Methicillin-Resistant Staphylococcus aureus in BAL: A Pilot Randomized Controlled Trial.

BACKGROUND: Guidelines recommend empirical vancomycin or linezolid for patients with suspected pneumonia at risk for methicillin-resistant Staphylococcus aureus (MRSA). Unneeded vancomycin or linezolid use may unnecessarily alter host flora and expose patients to toxicity. We therefore sought to determine if rapid testing for MRSA in BAL can safely decrease use of vancomycin or linezolid for suspected MRSA pneumonia. METHODS: Operating characteristics of the assay were initially validated against culture on residual BAL. A prospective, unblinded, randomized clinical trial to assess the effect of antibiotic management made on the basis of rapid diagnostic testing (RDT) compared with usual care was subsequently conducted, with primary outcome of duration of vancomycin or linezolid administration. Secondary end points focused on safety. RESULTS: Sensitivity of RPCR was 95.7%, with a negative likelihood ratio of 0.04 for MRSA. The clinical trial randomized 45 patients: 22 to antibiotic management made on the basis of RDT and 23 to usual care. Duration of vancomycin or linezolid administration was significantly reduced in the intervention group (32 h [interquartile range, 22-48] vs 72 h [interquartile range, 50-113], P < .001). Proportions with complications and length of stay trended lower in the intervention group. Hospital mortality was 13.6% in the intervention group and 39.1% for usual care (95% CI of difference, -3.3 to 50.3, P = .06). Standardized mortality ratio was 0.48 for the intervention group and 1.18 for usual care. CONCLUSIONS: A highly sensitive BAL RDT for MRSA significantly reduced use of vancomycin and linezolid in ventilated patients with suspected pneumonia. Management made on the basis of RDT had no adverse effects, with a trend to lower hospital mortality. TRIAL REGISTRY: ClinicalTrials.gov; No. NCT02660554; URL: www.clinicaltrials.gov.

Multidimensional Assessment of the Host Response in Mechanically Ventilated Patients with Suspected Pneumonia.

Rationale: The identification of informative elements of the host response to infection may improve the diagnosis and management of bacterial pneumonia. Objectives: To determine whether the absence of alveolar neutrophilia can exclude bacterial pneumonia in critically ill patients with suspected infection and to test whether signatures of bacterial pneumonia can be identified in the alveolar macrophage transcriptome. Methods: We determined the test characteristics of alveolar neutrophilia for the diagnosis of bacterial pneumonia in three cohorts of mechanically ventilated patients. In one cohort, we also isolated macrophages from alveolar lavage fluid and used the transcriptome to identify signatures of bacterial pneumonia. Finally, we developed a humanized mouse model of Pseudomonas aeruginosa pneumonia to determine if pathogen-specific signatures can be identified in human alveolar macrophages. Measurements and Main Results: An alveolar neutrophil percentage less than 50% had a negative predictive value of greater than 90% for bacterial pneumonia in both the retrospective (n = 851) and validation cohorts (n = 76 and n = 79). A transcriptional signature of bacterial pneumonia was present in both resident and recruited macrophages. Gene signatures from both cell types identified patients with bacterial pneumonia with test characteristics similar to alveolar neutrophilia. Conclusions: The absence of alveolar neutrophilia has a high negative predictive value for bacterial pneumonia in critically ill patients with suspected infection. Macrophages can be isolated from alveolar lavage fluid obtained during routine care and used for RNA-Seq analysis. This novel approach may facilitate a longitudinal and multidimensional assessment of the host response to bacterial pneumonia.

Assessment of the Perceived Acceptability of an Early Enrollment Strategy Using Advance Consent in Health Care-Associated Pneumonia.

Importance: Better treatment options are needed in life-threatening infections, including health care-associated pneumonia. Enrolling patients in antibacterial clinical trials before diagnosis may circumvent existing time-to-enrollment constraints. However, the acceptability of an early enrollment strategy using advance consent is unknown. Objective: To assess the perceived acceptability of an early enrollment strategy for enrolling patients in an antibacterial clinical trial before a pneumonia diagnosis. Design, Setting, and Participants: This qualitative, descriptive study used semistructured telephone interviews. Framed within a planned noninferiority pneumonia antibiotic trial, an early enrollment strategy was described and perceptions were assessed. Using this strategy, patients give consent to enroll before developing pneumonia, to be monitored by study staff, and to be randomly assigned a study antibiotic if pneumonia develops. All interviews were audiorecorded, transcribed verbatim, and analyzed using applied thematic analysis. Fifty-two key stakeholders from across the United States, including 18 patients at risk of pneumonia, 12 caregivers, 10 representatives of institutional review boards, 7 investigators, and 5 study coordinators, were interviewed from June 20 to August 19, 2016. Main Outcomes and Measures: Perceived acceptability of the early enrollment strategy. Results: Among the 52 stakeholders interviewed (ages 29-75 years; 14 women), patients and caregivers expressed no concerns about patients being approached about participation before developing pneumonia; however, some patients may experience anxiety on learning about their risk for pneumonia. No concerns with study staff accessing patients' medical records were expressed. The clarity of consent information was important for understanding the study rather than having the condition under investigation. Among patients, caregivers, and institutional review board representatives, preferences varied regarding opt-out and precedent autonomy procedures. Nearly all patients would be willing to join a trial using the early enrollment strategy and caregivers would be willing to provide proxy consent. Institutional review board representatives were supportive of the strategy and made recommendations for the study protocol, primarily around informed consent. Investigators and study coordinators believed the strategy would not be burdensome and offered suggestions to ensure its feasibility. Conclusion and Relevance: Results of the study suggest that the early enrollment strategy is acceptable. Future research should evaluate whether the strategy improves enrollment rates in registrational pneumonia trials and in trials of other acute infection syndromes with narrow enrollment windows and/or patients with transient decisional incapacity.

Dilution Factor of Quantitative Bacterial Cultures Obtained by Bronchoalveolar Lavage in Patients with Ventilator-Associated Bacterial Pneumonia.

Ventilator-associated bacterial pneumonia (VABP) is a difficult therapeutic problem. Considerable controversy exists regarding the optimal chemotherapy for this entity. The recent guidelines of the Infectious Diseases Society of America and the American Thoracic Society recommend a 7-day therapeutic course for VABP based on the balance of no negative impact on all-cause mortality, less resistance emergence, and fewer antibiotic treatment days, counterbalanced with a higher relapse rate for patients whose pathogen is a nonfermenter. The bacterial burden causing an infection has a substantial impact on treatment outcome and resistance selection. We describe the baseline bronchoalveolar lavage (BAL) fluid burden of organisms in suspected VABP patients screened for inclusion in a clinical trial. We measured the urea concentrations in plasma and BAL fluid to provide an index of the dilution of the bacterial and drug concentrations in the lung epithelial lining fluid introduced by the BAL procedure. We were then able to calculate the true bacterial burden as the diluted colony count times the dilution factor. The median dilution factor was 28.7, with the interquartile range (IQR) being 11.9 to 53.2. Median dilution factor-corrected colony counts were 6.18 log10(CFU/ml) [IQR, 5.43 to 6.46 log10(CFU/ml)]. In a subset of patients, repeat BAL on day 5 showed a good stability of the dilution factor. We previously showed that large bacterial burdens reduce or stop bacterial killing by granulocytes. (This study has been registered at ClinicalTrials.gov under registration no. NCT01570192.).

Streamlining Safety Data Collection in Hospital-Acquired Bacterial Pneumonia and Ventilator-Associated Bacterial Pneumonia Trials: Recommendations of the Clinical Trials Transformation Initiative Antibacterial Drug Development Project Team.

BACKGROUND: Resistant bacteria are one of the leading causes of hospital-acquired/ventilator-associated bacterial pneumonia (HABP/VABP). HABP/VABP trials are complex and difficult to conduct due to the large number of medical procedures, adverse events, and concomitant medications involved. Differences in the legislative frameworks between different regions of the world may also lead to excessive data collection. The Clinical Trials Transformation Initiative (CTTI) seeks to advance antibacterial drug development (ABDD) by streamlining clinical trials to improve efficiency and feasibility while maintaining ethical rigor, patient safety, information value, and scientific validity. METHODS: In 2013, CTTI engaged a multidisciplinary group of experts to discuss challenges impeding the conduct of HABP/VABP trials. Separate workstreams identified challenges associated with current data collection processes. Experts defined "data collection" as the act of capturing and reporting certain data on the case report form as opposed to recording of data as part of routine clinical care. The ABDD Project Team developed strategies for streamlining safety data collection in HABP/VABP trials using a Quality by Design approach. RESULTS: Current safety data collection processes in HABP/VABP trials often include extraneous information. More targeted strategies for safety data collection in HABP/VABP trials will rely on optimal protocol design and prespecification of which safety data are essential to satisfy regulatory reporting requirements. CONCLUSIONS: A consensus and a cultural change in clinical trial design and conduct, which involve recognition of the need for more efficient data collection, are urgently needed to advance ABDD and to improve HABP/VABP trials in particular.

Community-Acquired Pneumonia Requiring Hospitalization among U.S. Adults.

BACKGROUND: Community-acquired pneumonia is a leading infectious cause of hospitalization and death among U.S. adults. Incidence estimates of pneumonia confirmed radiographically and with the use of current laboratory diagnostic tests are needed. METHODS: We conducted active population-based surveillance for community-acquired pneumonia requiring hospitalization among adults 18 years of age or older in five hospitals in Chicago and Nashville. Patients with recent hospitalization or severe immunosuppression were excluded. Blood, urine, and respiratory specimens were systematically collected for culture, serologic testing, antigen detection, and molecular diagnostic testing. Study radiologists independently reviewed chest radiographs. We calculated population-based incidence rates of community-acquired pneumonia requiring hospitalization according to age and pathogen. RESULTS: From January 2010 through June 2012, we enrolled 2488 of 3634 eligible adults (68%). Among 2320 adults with radiographic evidence of pneumonia (93%), the median age of the patients was 57 years (interquartile range, 46 to 71); 498 patients (21%) required intensive care, and 52 (2%) died. Among 2259 patients who had radiographic evidence of pneumonia and specimens available for both bacterial and viral testing, a pathogen was detected in 853 (38%): one or more viruses in 530 (23%), bacteria in 247 (11%), bacterial and viral pathogens in 59 (3%), and a fungal or mycobacterial pathogen in 17 (1%). The most common pathogens were human rhinovirus (in 9% of patients), influenza virus (in 6%), and Streptococcus pneumoniae (in 5%). The annual incidence of pneumonia was 24.8 cases (95% confidence interval, 23.5 to 26.1) per 10,000 adults, with the highest rates among adults 65 to 79 years of age (63.0 cases per 10,000 adults) and those 80 years of age or older (164.3 cases per 10,000 adults). For each pathogen, the incidence increased with age. CONCLUSIONS: The incidence of community-acquired pneumonia requiring hospitalization was highest among the oldest adults. Despite current diagnostic tests, no pathogen was detected in the majority of patients. Respiratory viruses were detected more frequently than bacteria. (Funded by the Influenza Division of the National Center for Immunizations and Respiratory Diseases.).