Diagnostic fiberoptic bronchoscopy and protected brush culture in patients with community-acquired pneumonia

Treatment Failure and Clinical Stability in Severe Community-Acquired Pneumonia

Treatment failure and clinical stability are important outcomes in community-acquired pneumonia (CAP). It is essential to know the causes and risk factors for treatment failure and delay in reaching clinical stability in CAP. The study of both as well as the associated underlying mechanisms and host response are key to improving outcomes in pneumonia.

E-cigarette, or vaping, product use associated lung injury (EVALI): case series and diagnostic approach

BACKGROUND

Since June, 2019, more than 1000 new cases of e-cigarette, or vaping, product use associated lung injury (EVALI) have been reported in the USA. Patients presented with dyspnoea, cough, and were found to be hypoxaemic with bilateral airspace opacities on chest imaging. Most patients required management in the intensive care unit and steroid therapy. All patients recovered with cessation of vaping, supportive care, and steroid therapy and remained symptom free at follow up. E-cigarette use continues to rapidly escalate in the USA, particularly among youth.

METHODS

Cases were defined as patients admitted to the University of Rochester Medical Center (Rochester, NY, USA) who had used e-cigarettes or another vaping device in the 30 days before presentation, and who had bilateral airspace opacification on chest imaging (CT or x-ray). Case details were obtained via medical record review and patient interviews over the past 3 months including symptomatology, physical exam data, imaging studies, laboratory data, vaping history, and subsequent outpatient follow-up data. In collaboration with the New York State Department of Health, our hospital developed a novel clinical practice algorithm based on statewide physician feedback along with input from experts in environmental health, medical toxicology, infectious disease, epidemiology, and chronic disease prevention.

FINDINGS

We report 12 cases treated for suspected EVALI at our medical centre between June 6, 2019, and Sept 15, 2019. Ten (83%) patients had dyspnoea, fever, and emesis and nine (75%) had cough. 11 (92%) patients reported the use of e-cigarette cartridges containing tetrahydrocannabinol oil. Although eight (67%) patients required admission to the intensive care unit for hypoxaemic respiratory failure, no deaths occurred. The median hospitalisation duration was 7 days (IQR 7-8). All patients completing follow up (6 [50%]) had resolution of previous chest CT findings and normal spirometry. The clinical algorithm focuses on the key signs and symptoms of EVALI and the importance of ruling out infection and other cardiopulmonary conditions before making a presumptive diagnosis of EVALI.

INTERPRETATION

Patients with suspected EVALI in our cohort had life-threatening hypoxaemia, with 67% requiring management in the intensive care unit. Despite the severity of presentation, similar to previous reports of patients with EVALI, most patients improved within 1-2 weeks of initial presentation after vaping cessation and administration of systemic corticosteroids when needed. Almost all (92%) patients with suspected EVALI reported vaping a THC product, making THC containing e-liquids or oils a key focus on the ongoing nationwide investigations into the cause of EVALI. Additional research is required to understand the potential toxins, underlying pathophysiological mechanisms, and identification of susceptible individuals at higher risk for hospitalisation due to EVALI. To our knowledge we present the first clinical practice algorithm for the evaluation and management of EVALI, which will be useful for both acute management and improved accurate reporting of this life-threatening respiratory illness.

FUNDING

None.

Community-acquired Pneumonia and Hospital-acquired Pneumonia

Pneumonia is among the leading causes of morbidity and mortality worldwide. Although Streptococcus pneumoniae is the most likely cause in most cases, the variety of potential pathogens can make choosing a management strategy a complex endeavor. The setting in which pneumonia is acquired heavily influences diagnostic and therapeutic choices. Because the causative organism is typically unknown early on, timely administration of empiric antibiotics is a cornerstone of pneumonia management. Disease severity and rates of antibiotic resistance should be carefully considered when choosing an empiric regimen. When complications arise, further work-up and consultation with a pulmonary specialist may be necessary.

Use of an innovative and non-invasive device for virologic sampling of cough aerosols in patients with community and hospital acquired pneumonia: a pilot study

BACKGROUND

The aetiology of lower respiratory tract infections is challenging to investigate. Despite the wide array of diagnostic tools, invasive techniques, such as bronchoalveolar lavage (BAL), are often required to obtain adequate specimens. PneumoniaCheckTM is a new device that collects aerosol particles from cough, allowing microbiological analyses. Up to now it has been tested only for bacteria detection, but no study has investigated its usefulness for virus identification.

METHODS

In this pilot study we included 12 consecutive patients with pneumonia. After testing cough adequacy via a peak flow meter, a sampling with PneumoniaCheckTM was collected and a BAL was performed in each patient. Microbiological analyses for virus identification were performed on each sample and concordance between the two techniques was tested (sensitivity, specificity and positive/negative predictive values), taking BAL results as reference.

RESULTS

BAL was considered adequate in 10 patients. Among them, a viral pathogen was identified by PneumoniaCheckTM 6 times, each on different samples, whereas BAL allowed to detect the presence of a virus on 7 patients (14 positivities). Overall, the specificity for PneumoniaCheckTM to detect a virus was 100%, whereas the sensitivity was 66%. When considering only herpes viruses, PneumoniaCheckTM showed a lower sensitivity, detecting a virus in 1/4 of infected patients (25%).

CONCLUSIONS

In this pilot study PneumoniaCheckTM showed a good correlation with BAL for non-herpes virologic identification in pneumonia patients, providing excellent specificity. Further studies on larger population are needed to confirm these results and define its place in the panorama of rapid diagnostic tests for lower respiratory tract infections.

The significance of oral streptococci in patients with pneumonia with risk factors for aspiration: the bacterial floral analysis of 16S ribosomal RNA gene using bronchoalveolar lavage fluid

Background

Aspiration pneumonia has been a growing interest in an aging population. Anaerobes are important pathogens, however, the etiology of aspiration pneumonia is not fully understood. In addition, the relationship between the patient clinical characteristics and the causative pathogens in pneumonia patients with aspiration risk factors are unclear. To evaluate the relationship between the patient clinical characteristics with risk factors for aspiration and bacterial flora in bronchoalveolar lavage fluid (BALF) in pneumonia patients, the bacterial floral analysis of 16S ribosomal RNA gene was applied in addition to cultivation methods in BALF samples.

Methods

From April 2010 to February 2014, BALF samples were obtained from the affected lesions of pneumonia via bronchoscopy, and were evaluated by the bacterial floral analysis of 16S rRNA gene in addition to cultivation methods in patients with community-acquired pneumonia (CAP) and healthcare-associated pneumonia (HCAP). Factors associated with aspiration risks in these patients were analyzed.

Results

A total of 177 (CAP 83, HCAP 94) patients were enrolled. According to the results of the bacterial floral analysis, detection rate of oral streptococci as the most detected bacterial phylotypes in BALF was significantly higher in patients with aspiration risks (31.0 %) than in patients without aspiration risks (14.7 %) (P = 0.009). In addition, the percentages of oral streptococci in each BALF sample were significantly higher in patients with aspiration risks (26.6 ± 32.0 %) than in patients without aspiration risks (13.8 ± 25.3 %) (P = 0.002). A multiple linear regression analysis showed that an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of ≥3, the presence of comorbidities, and a history of pneumonia within a previous year were significantly associated with a detection of oral streptococci in BALF.

Conclusions

The bacterial floral analysis of 16S rRNA gene revealed that oral streptococci were mostly detected as the most detected bacterial phylotypes in BALF samples in CAP and HCAP patients with aspiration risks, especially in those with a poor ECOG-PS or a history of pneumonia.

Community-acquired pneumonia: identification and evaluation of nonresponders

Community acquired pneumonia (CAP) is a relevant public health problem, constituting an important cause of morbidity and mortality. It accounts for a significant number of adult hospital admissions and a large number of those patients ultimately die, especially the population who needed mechanical ventilation or vasopressor support. Thus, early identification of CAP patients and its rapid and appropriate treatment are important features with impact on hospital resource consumption and overall mortality. Although CAP diagnosis may sometimes be straightforward, the diagnostic criteria commonly used are highly sensitive but largely unspecific. Biomarkers and microbiological documentation may be useful but have important limitations. Evaluation of clinical response is also critical especially to identify patients who fail to respond to initial treatment since these patients have a high risk of in-hospital death. However, the criteria of definition of non-response in CAP are largely empirical and frequently markedly diverse between different studies. In this review, we aim to identify criteria defining nonresponse in CAP and the pitfalls associated with this diagnosis. We also aim to overview the main causes of treatment failure especially in severe CAP and the possible strategies to identify and reassess non-responders trying to change the dismal prognosis associated with this condition.

Assessing bacterial populations in the lung by replicate analysis of samples from the upper and lower respiratory tracts

Microbes of the human respiratory tract are important in health and disease, but accurate sampling of the lung presents challenges. Lung microbes are commonly sampled by bronchoscopy, but to acquire samples the bronchoscope must pass through the upper respiratory tract, which is rich in microbes. Here we present methods to identify authentic lung microbiota in bronchoalveolar lavage (BAL) fluid that contains substantial oropharyngeal admixture. We studied clinical BAL samples from six selected subjects with potential heavy lung colonization. A single sample of BAL fluid was obtained from each subject along with contemporaneous oral wash (OW) to sample the oropharynx, and then DNA was extracted from three separate aliquots of each. Bacterial 16S rDNA sequences were amplified and products analyzed by 454 pyrosequencing. By comparing replicates, we were able to specify the depth of sequencing needed to reach a 95% chance of identifying a bacterial lineage of a given proportion—for example, at a depth of 5,000 tags, OTUs of proportion 0.3% or greater would be called with 95% confidence. We next constructed a single-sided outlier test that allowed lung-enriched organisms to be quantified against a background of oropharyngeal admixture, and assessed improvements available with replicate sequence analysis. This allowed identification of lineages enriched in lung in some BAL specimens. Finally, using samples from healthy volunteers collected at multiple sites in the upper respiratory tract, we show that OW provides a reasonable but not perfect surrogate for bacteria carried into to the lung by a bronchoscope. These methods allow identification of microbes that can replicate in the lung despite the background due to oropharyngeal microbes derived from aspiration and bronchoscopic carry-over.

Topographical continuity of bacterial populations in the healthy human respiratory tract

RATIONALE

Defining the biogeography of bacterial populations in human body habitats is a high priority for understanding microbial-host relationships in health and disease. The healthy lung was traditionally considered sterile, but this notion has been challenged by emerging molecular approaches that enable comprehensive examination of microbial communities. However, studies of the lung are challenging due to difficulties in working with low biomass samples.

OBJECTIVES

Our goal was to use molecular methods to define the bacterial microbiota present in the lungs of healthy individuals and assess its relationship to upper airway populations.

METHODS

We sampled respiratory flora intensively at multiple sites in six healthy individuals. The upper tract was sampled by oral wash and oro-/nasopharyngeal swabs. Two bronchoscopes were used to collect samples up to the glottis, followed by serial bronchoalveolar lavage and lower airway protected brush. Bacterial abundance and composition were analyzed by 16S rDNA Q-PCR and deep sequencing.

MEASUREMENTS AND MAIN RESULTS

Bacterial communities from the lung displayed composition indistinguishable from the upper airways, but were 2 to 4 logs lower in biomass. Lung-specific sequences were rare and not shared among individuals. There was no unique lung microbiome.

CONCLUSIONS

In contrast to other organ systems, the respiratory tract harbors a homogenous microbiota that decreases in biomass from upper to lower tract. The healthy lung does not contain a consistent distinct microbiome, but instead contains low levels of bacterial sequences largely indistinguishable from upper respiratory flora. These findings establish baseline data for healthy subjects and sampling approaches for sequence-based analysis of diseases.

Comparative antibiotic failure rates in the treatment of community-acquired pneumonia: Results from a claims analysis

INTRODUCTION

Antibiotic treatment failure contributes to the economic and humanistic burdens of community-acquired pneumonia (CAP) by increasing morbidity, mortality, and healthcare costs. This study compared treatment failure rates of levofloxacin with those of other antibiotics in a large US sample.

METHODS

Medical and pharmacy claims in the nationally representative SDI database were used to identify adults with a new outpatient diagnosis of CAP receiving a study antibiotic (levofloxacin, amoxicillin/clavulanate, azithromycin, moxifloxacin) between September 1, 2005 and March 31, 2008. Treatment failure was defined as ≥1 of the following events ≤30 days after index date: a refill for the index antibiotic after completed days of therapy, a different antibiotic dispensed >1 day after the index prescription, or hospitalization with a pneumonia diagnosis or emergency department visit >3 days postindex. Cohorts were propensity score matched for demographic and clinical characteristics. Treatment failure rates were compared between pairs of cohorts for the full sample and for high-risk patients (age ≥65 and/or on Medicaid).

RESULTS

Among the 3994 study patients, the numbers of dispensed index prescriptions were 268 for amoxicillin/clavulanate, 1609 for azithromycin, 1460 for levofloxacin, and 657 for moxifloxacin. Unadjusted treatment failure rates for the sample were 20.8% for levofloxacin, 23.9% for amoxicillin/clavulanate, 23.9% for azithromycin, and 19.9% for moxifloxacin. For high-risk patients, unadjusted treatment failure rates were 19.1% for levofloxacin, 26.1% for amoxicillin/clavulanate, 26.3% for azithromycin, and 24.3% for moxifloxacin. Propensity score-matched treatment failure rates were significantly lower with levofloxacin than azithromycin (19.8% vs. 24.5%, odds ratio [OR] comparator vs. levofloxacin 1.38; 95% CI: 1.14, 1.67), a difference amplified in high-risk patients (19.0% vs. 26.4%, OR 1.61; 95% CI: 1.22, 2.13). No significant differences were observed for other paired comparisons.

CONCLUSION

In a large US sample, treatment failure in CAP appeared to be less likely with quinolones (such as levofloxacin) than azithromycin, an effect particularly marked in high-risk patients (age ≥65 and/or on Medicaid).

Community acquired bacterial pneumonia

IMPORTANCE OF THE FIELD

Community-acquired pneumonia (CAP) is a common and potentially life-threatening illness that continues to be a major medical problem. Among infectious diseases, CAP is the leading cause of death in the world and is associated with a substantial economic burden to health are systems around the globe.

AREAS COVERED IN THIS REVIEW

Recently identified clinical and biochemical tools promise to improve the assessment of CAP severity. Various prognostic scoring systems and predictive biomarkers have been proposed as tools to aid clinicians in key management decisions. This review provides a summary of current evidence about the use of prognostic scoring systems and biomarkers in the management of patients presenting with CAP. According to the existing guidelines, until more accurate and rapid diagnostic methods are available, the initial treatment for most patients with CAP will remain empirical. Some novel antibiotic and nonantibiotic therapies have recently been tested; some empirical antimicrobial regimens are still being debated. This review summarizes the recent advances in the field of therapy and novel approaches. We searched PubMed for English-language references published from 1997 to 2009 using combinations of the following terms: 'community acquired pneumonia', 'community acquired bacterial pneumonia', 'therapy', 'antibiotics', 'antimicrobials', 'prognostic scoring systems', 'biomarkers', 'diagnostic testing', 'guidelines' 'etiological diagnosis'.

WHAT THE READER WILL GAIN

A thorough description about recent advances in the field of therapy and novel approaches of CAP, as well as a summary of current evidence about the use of prognostic scoring systems and biomarkers in the management of patients presenting with CAP, is presented.

TAKE HOME MESSAGE

Recent developments have made significant contributions to the management of CAP patients. However, various hot topics remain open and urgently require prospective studies in order to optimize the outcomes of CAP.

Brazilian guidelines for community-acquired pneumonia in immunocompetent adults - 2009

Community-acquired pneumonia continues to be the acute infectious disease that has the greatest medical and social impact regarding morbidity and treatment costs. Children and the elderly are more susceptible to severe complications, thereby justifying the fact that the prevention measures adopted have focused on these age brackets. Despite the advances in the knowledge of etiology and physiopathology, as well as the improvement in preliminary clinical and therapeutic methods, various questions merit further investigation. This is due to the clinical, social, demographical and structural diversity, which cannot be fully predicted. Consequently, guidelines are published in order to compile the most recent knowledge in a systematic way and to promote the rational use of that knowledge in medical practice. Therefore, guidelines are not a rigid set of rules that must be followed, but first and foremost a tool to be used in a critical way, bearing in mind the variability of biological and human responses within their individual and social contexts. This document represents the conclusion of a detailed discussion among the members of the Scientific Board and Respiratory Infection Committee of the Brazilian Thoracic Association. The objective of the work group was to present relevant topics in order to update the previous guidelines. We attempted to avoid the repetition of consensual concepts. The principal objective of creating this document was to present a compilation of the recent advances published in the literature and, consequently, to contribute to improving the quality of the medical care provided to immunocompetent adult patients with community-acquired pneumonia.

The impact on community acquired pneumonia empirical therapy of diagnostic bronchoscopic techniques

The aim of the present study was to examine the modification of initial empirical treatment based on the microbiological results of bronchoscopic techniques after comparing the diagnostic yield of protected specimen brush (PSB) and bronchoalveolar lavage (BAL) in the immunocompetent patient with community acquired pneumonia (CAP) with results obtained from conventional sputum cultures. 88 patients with presumptive diagnosis of CAP necessitating hospitalization were prospectively studied. Fibreoptic bronchoscopy with quantitative PSB and BAL cultures for common pathogens, mycobacteria and fungi was performed. Conventional sputum cultures were also obtained. PSB and BAL quantitative cultures added 26.1% and 36.4%, respectively, more microbiological documentation for CAP compared to conventional sputum cultures (p < 0.0001). Gram staining was indicative of the pathogen mostly in cases where Streptococcus pneumoniae was isolated, which was also the most frequently isolated pathogen (19.3%), followed by Haemophilus influenzae (9%). M. tuberculosis was isolated in 6.8% of patients. Modification of treatment ensued in 27.3% of patients because of the application of the cultures of sputum and invasive technique. PSB and BAL added significant information to the aetiological diagnosis of hospitalized immunocompetent patients with CAP.

Bacterial Infections

In Osier’s time, bacterial pneumonia was a dreaded event, so important that he borrowed John Bunyan’s characterization of tuberculosis and anointed the pneumococcus, as the prime pathogen, “Captain of the men of death.”1 One hundred years later much has changed, but much remains the same. Pneumonia is now the sixth most common cause of death and the most common lethal infection in the United States. Hospital-acquired pneumonia is now the second most common nosocomial infection.2 It was documented as a complication in 0.6% of patients in a national surveillance study,3 and has been reported in as many as 20% of patients in critical care units.4 Furthermore, it is the leading cause of death among nosocomial infections.5 Leu and colleagues6 were able to associate one third of the mortality in patients with nosocomial pneumonia to the infection itself. The increase in hospital stay, which averaged 7 days, was statistically significant. It has been estimated that nosocomial pneumonia produces costs in excess of $500 million each year in the United States, largely related to the increased length of hospital stay.

Treatment failure in community-acquired pneumonia

Treatment failure (TF) is defined as a clinical condition with inadequate response to antimicrobial therapy. Clinical response should be evaluated within the first 72 h of treatment, whereas infiltrate images may take up to 6 weeks to resolve. Early failure is considered when ventilatory support and/or septic shock appear within the first 72 h. The incidence of treatment failure in community-acquired pneumonia is 10 to 15%, and the mortality is increased nearly fivefold. Resistant and unusual microorganisms and noninfectious causes are responsible for TF. Risk factors are related to the initial severity of the disease, the presence of comorbidity, the microorganism involved, and the antimicrobial treatment implemented. Characteristics of patients and factors related to inflammatory response have been associated with delayed resolution and poor prognosis. The diagnostic approach to TF depends on the degree of clinical impact, host factors, and the possible cause. Initial reevaluation should include a confirmation of the diagnosis of pneumonia, noninvasive microbiological samples, and new radiographic studies. A conservative approach of clinical monitoring and serial radiographs may be recommended in elderly patients with comorbid conditions that justify a delayed response. Invasive studies with bronchoscopy to obtain protected brush specimen and BAL are indicated in the presence of clinical deterioration or failure to stabilize. BAL processing should include the study of cell patterns to rule out other noninfectious diseases and complete microbiological studies. The diagnostic yield of imaging procedures with noninvasive and invasive samples is up to 70%. After obtaining microbiological samples, an empirical change in antibiotic therapy is required to cover a wider microbial spectrum.

[Follow-up criteria for community acquired pneumonias and acute exacerbations of chronic obstructive pulmonary disease]

The follow-up of Community Acquired Pneumonias (CAP) and Acute Exacerbations of Chronic Obstructive Pulmonary Diseases (AECOPD) differs with the setting of care, but overall calls upon the same investigations as the initial evaluations. In the event of initial ambulatory care, the evaluation is carried out primarily on clinical data, at the 2 or 3rd day for the CAP, at the 2nd to 5th day for the AECOPD. In the event of unfavourable evolution, or from the start in the most severe cases, the follow-up is carried out in hospital; clinical evaluation is readily daily, and all the more frequent that the clinical condition is worrying because of the severity or risk factors. The investigations will be limited to those initially abnormal in the event of favourable evolution; on the contrary, unfavourable evolution can justify new investigations which depend on clinical characteristics. Remotely, i.e. 4 to 8 weeks later, must be checked the return at the baseline clinical state, a chest X-ray (CAP), spirometry and arterial blood gas (AECOPD), even bronchoscopy and thoracic CT-scan.

[Contribution of microbiological investigations to the diagnosis of lower respiratory tract infections]

The diagnosis of community-acquired pneumonia is usually based on clinical and radiological criteria. The identification of a causative organism is not required for the diagnosis. Although numerous microbiological techniques are available, their sensitivity and specificity are not high enough to guide first-line antimicrobial therapy. Consequently, this treatment remains most often empiric. If the causative organism is identified, the antimicrobial treatment is adapted. Sputum analysis may be proposed as a diagnostic tool for patients with an acute exacerbation of chronic obstructive pulmonary disease, in specific cases (prior antibiotherapy, hospitalization, failure of the empiric antimicrobial treatment).

Prognostic factors for early clinical failure in patients with severe community-acquired pneumonia

For patients with community-acquired pneumonia (CAP), clinical response during the first days of treatment is predictive of clinical outcome. As risk assessments can improve the efficiency of pneumonia management, a prospective cohort study to assess clinical, biochemical and microbiological predictors of early clinical failure was conducted in patients with severe CAP (pneumonia severity index score of >90 or according to the American Thoracic Society definition). Failure was assessed at day 3 and was defined as death, a need for mechanical ventilation, respiratory rate >25/min, PaO2 <55 mm Hg, oxygen saturation <90%, haemodynamic instability, temperature >38 degrees C or confusion. Of 260 patients, 80 (31%) had early clinical failure, associated mainly with a respiratory rate >25/minute (n = 34), oxygen saturation <90% (n = 28) and confusion (n = 20). In multivariate logistic regression analysis, failure was associated independently with altered mental state (OR 3.19, 95% CI 1.75-5.80), arterial PaH <7.35 mm Hg (OR 4.29, 95% CI 1.53-12.05) and PaO2 <60 mm Hg (OR 1.75, 95% CI 0.97-3.15). A history of heart failure was associated inversely with clinical failure (OR 0.30, 95% CI 0.10-0.96). Patients who failed to respond had a higher 28-day mortality rate and a longer hospital stay. It was concluded that routine clinical and biochemical information can be used to predict early clinical failure in patients with severe CAP.

Neumonías comunitarias graves del adulto

Las neumonías agudas comunitarias son causa frecuente de hospitalización y mortalidad. El reconocimiento inmediato de las formas graves según criterios simples, clínicos, radiológicos y de laboratorio, es una etapa esencial para un tratamiento rápido en el servicio de reanimación con el fin de controlar los fallos orgánicos. La obtención de muestras apropiadas para realizar estudios microbiológicos precede al tratamiento antibiótico, que se debe instaurar con rapidez después de diagnosticar la neumonía. Pese a las técnicas de identificación, sólo la mitad de las neumonías se documentan adecuadamente. El tratamiento antibiótico, en principio empírico, integra los gérmenes patógenos, tanto extracelulares como intracelulares, que producen neumonías con mayor frecuencia; siempre debe ser activo contra el neumococo, la bacteria implicada más a menudo. La asociación de un betalactámico y un macrólido o una fluoroquinolona es la que mejor responde a este objetivo. En las recomendaciones más comunes, las fluoroquinolonas activas contra los neumococos sustituyen a los fármacos precedentes. En el caso excepcional de los pacientes con factores de riesgo especiales, el tratamiento empírico debe tener en cuenta Pseudomonas aeruginosa. La gravedad de parte de las neumonías comunitarias justifica el que se recurra a tratamientos complementarios. Se debe evaluar de nuevo el tratamiento antibiótico en las 72 horas siguientes a su instauración, a fin de valorar su eficacia, adaptar el tratamiento en caso necesario y simplificarlo. El mantenimiento de antibióticos de amplio espectro expone al paciente a efectos secundarios y contribuye a producir resistencias bacterianas. En cuanto a las neumonías neumocócicas, las fluoroquinolonas activas contra el neumococo podrían representar una alternativa en caso de que el neumococo desarrolle resistencia a los betalactámicos. La mortalidad persistente de las neumonías sigue siendo notable. Esto debe fomentar la mejora del tratamiento inicial y la búsqueda de nuevas opciones terapéuticas.

Antibiotic treatment and the diagnosis of Streptococcus pneumoniae in lower respiratory tract infections in adults

OBJECTIVE

To analyze the possible influence of antibiotic treatment on the results of different diagnostic tests for the diagnosis of lower respiratory tract infections with Streptococcus pneumoniae.

MATERIAL AND METHODS

A prospective cohort of 159 unselected adult immunocompetent patients admitted to Silkeborg County Hospital in Denmark with community-acquired lower respiratory tract infections underwent microbiological investigations with fiber-optic bronchoscopy with bronchoalveolar lavage, blood and sputum culture and urine antigen test for type-specific polysaccharide capsular antigens of S. pneumoniae.

RESULTS

When stratified for antibiotic treatment prior to microbiological sampling, three different groups of patients with documented or probable infection with S. pneumoniae could be identified. The first group comprised 14 patients who were culture positive in one or more culture tests, where most (11/14) did not receive any antibiotic treatment within 24 hours of sampling. The second group consisted of nine patients with a positive urine antigen test where 8/9 and 9/9 received antibiotic treatment 24 and 48 hours, respectively, prior to urine sampling. Only a single patient was positive in both systems, making a total of 22 patients with documented pneumococcal infection. As a positive culture test was dependent on the absence of antibiotic treatment, whereas a positive urine antigen test depended on antibiotic treatment within 48 hours, the two tests were complementary in the diagnosis of infection with S. pneumoniae. The third group of patients with probable pneumococcal infection were identified as 26% and 20% of the remaining 137 patients with unknown or known non-pneumococcal etiology, respectively, who received recent antibiotic treatment within 2-4 weeks of diagnostic sampling. By comparison, 0% (p < 0.01) with documented pneumococcal infection received antibiotic treatment in weeks 2-4 prior to microbiological sampling. As such a further eight patients should be expected to have infection with S. pneumoniae but would test negative in both culture tests and the urine antigen test because of antibiotic treatment within weeks 2-4 prior to sampling.

CONCLUSION

The diagnosis of infection with S. pneumoniae is very dependent on whether or not recent (within 2-4 weeks) or immediate (within 48 hours) antibiotic treatment has been given prior to microbiological sampling of patients. The results suggest an optimized diagnostic strategy with, if possible, sampling for culture prior to antibiotic treatment, while sampling for pneumococcal antigens should wait 24-48 hours for antibiotic treatment.

Progressive and nonresolving pneumonia

PURPOSE OF REVIEW

Patients with progressive and/or nonresolving community-acquired pneumonia are at risk for increased morbidity and mortality. It is critical to be able to identify patients at risk to institute early appropriate therapy. The purpose of this review is to summarise the most updated developments in this area.

RECENT FINDINGS

This review will glean from the recent literature clinical, laboratory, and radiologic findings that help identify patients at risk for such complications of their pneumonia. New studies will be reviewed that have identified some of the causes for treatment failures including the type of pathogen and discordant antimicrobial therapy. It will also discuss newly recognised and emerging infectious diseases that may result in progressive or nonresponding pneumonia including severe acute respiratory syndrome, avian influenzae, severe group A streptococcal disease, and community-acquired methicillin-resistant Staphylococcus aureus. Promising treatments have been identified for patients with progressive pneumonia due to an overwhelming host immune response including activated protein C and intravenous immunoglobulin.

SUMMARY

Both progressive and nonresolving pneumonia represent treatment failure as a result of inappropriate initial therapy, a noninfectious cause, or an overwhelming immune response. It is critical to be able to identify patients with nonresponding pneumonia and to identify patients at risk for progressive pneumonia to institute appropriate therapy.

Value of intensive diagnostic microbiological investigation in low- and high-risk patients with community-acquired pneumonia

In a prospective study to evaluate the diagnostic yield of different microbiological tests in hospitalised patients with community-acquired pneumonia, material for microbiological investigation was obtained from 262 patients. Clinical samples consisted of the following: sputum for Gram staining, culture, and detection of pneumococcal antigen; blood for culture and serological tests; urine for detection of Legionella pneumophila serogroup 1 antigen and pneumococcal antigen; and specimens obtained by fiberoptic bronchoscopy. A pathogen was identified in 158 (60%) patients, with Streptococcus pneumoniae (n=97) being the most common causative agent of community-acquired pneumonia. In 82% of the 44 patients with an adequate sputum specimen, a positive Gram stain was confirmed by positive sputum culture. S. pneumoniae infections were detected principally when adequate sputum specimens were examined by Gram stain and culture and when adequate and inadequate sputum specimens were tested for the presence of pneumococcal antigen (n=58; 60%). The urinary pneumococcal antigen test was the most valuable single test for detection of S. pneumoniae infections (n=52; 54%) when sputum pneumococcal antigen determination was not performed. Fiberoptic bronchoscopy was of additive diagnostic value in 49% of the patients who did not expectorate sputum and in 52% of those in whom treatment failed. Investigation of sputum by a combination of Gram stain, culture, and detection of pneumococcal antigen was the most useful means of establishing an aetiological diagnosis of community-acquired pneumonia, followed by testing of urine for pneumococcal antigen. Fiberoptic bronchoscopy may be of additional value when treatment failure occurs.

Pneumonies communautaires graves de l'adulte

Les pneumonies aiguës communautaires sont des causes fréquentes d'hospitalisation et de mortalité. La reconnaissance immédiate des formes sévères sur des critères simples, cliniques, radiologiques et biologiques, est une étape importante pour une prise en charge rapide en réanimation afin de contrôler les défaillances d'organes. Les prélèvements appropriés microbiologiques précèdent l'antibiothérapie qui doit être instituée très rapidement après le diagnostic de pneumonie. Malgré les techniques d'identification, la moitié seulement des pneumonies sont documentées. Cette antibiothérapie, initialement probabiliste, intègre les germes pathogènes les plus souvent responsables, extra- et intracellulaires ; elle doit toujours être active sur le pneumocoque, bactérie la plus fréquente. L'association d'une β-lactamine et d'un macrolide ou d'une fluoroquinolone répond le mieux à cet objectif. Les fluoroquinolones actives sur le pneumocoque se sont substituées aux précédentes dans les plus récentes recommandations. Dans le cas exceptionnel des patients ayant des facteurs de risque particuliers, le traitement probabiliste doit prendre en compte Pseudomonas aeruginosa. La gravité d'une partie des pneumonies communautaires justifie le recours à des traitements adjuvants. L'antibiothérapie doit être réévaluée dans les 72 heures dans le but d'apprécier son efficacité, de l'adapter éventuellement et de la simplifier. La poursuite des antibiotiques à large spectre expose le patient à des effets indésirables et contribue aux résistances bactériennes. Pour les pneumonies dues au pneumocoque, les fluoroquinolones actives sur le pneumocoque pourront constituer une alternative en cas d'évolution importante des résistances du pneumocoque aux β-lactamines. La mortalité persistante des pneumonies reste sévère. Ceci doit stimuler l'amélioration de la prise en charge initiale et faire rechercher de nouvelles thérapeutiques.

Bacteremic pneumococcal pneumonia: a prospective study in Edmonton and neighboring municipalities

Bacteremic pneumococcal pneumonia (BPP) is an important disease that should be frequently re-evaluated due to changes in demographics and recommended treatment. We conducted a prospective study from 2000 to 2002 in adults aged 17 years and over who presented to any of 6 hospitals and 1 freestanding emergency room in Edmonton, Alberta, with signs and symptoms compatible with pneumonia, a chest radiograph interpreted as pneumonia by the attending physician, and a positive blood culture for Streptococcus pneumoniae. We identified 129 patients with BPP, for an overall incidence of 9.7/100,000 person years. The rate was markedly higher among pregnant women, homeless persons, and those in prison. Sixteen percent were managed as outpatients, 61.2% as ward patients, and 22.5% required admission to the intensive care unit (ICU). Tobacco smoking was predictive of BPP, and antibiotic therapy before presentation was protective. According to pneumonia severity index, 47.3% were in low-risk classes I-III, 31.0% were in class IV, and 21.7% were in class V. Twelve (9.3%) patients died. Four died within 24 hours of arrival at hospital, and 2 had end-stage lung disease that resulted in a decision to discontinue therapy. Of the S. pneumoniae isolates, 12.5% were not susceptible to penicillin. The overall rate of BPP appears to be decreasing, although the rate is markedly increased in certain populations, which now should be targeted for vaccination. We identified 3 subsets of patients with BPP according to the site of care (ambulatory, ward, and ICU), with different outcomes.

Nonresolving Pneumonia

Uncertainty over the expected clinical course of a community-acquired or nosocomial pneumonia is a common reason for pulmonary consultation. Determining which patients with prolonged pneumonia and at what point during therapy they should undergo further evaluation can be challenging. This article reviews "normal" resolution times for the most common pneumonias, risk factors for delayed resolution, and infectious and noninfectious conditions that can cause nonresolving pneumonia. An approach to the evaluation of the patient with this common problem is described.

[Guidelines for the management of community pneumonia in adult who needs hospitalization]

Community acquired pneumonia is still an important health problem. In Spain the year incidence is 162 cases per 100,000 inhabitants with 53,000 hospital admission costing 115 millions of euros per year. In the last years there have been significant advances in the knowledge of: aetiology, diagnostic tools, treatment alternatives and antibiotic resistance. The Spanish Societies of Intensive and Critical Care (SEMICYUC), Infectious Diseases and Clinical Microbiology (SEIMC) and Pulmonology and Thoracic Surgery (SEPAR) have produced these evidence-based Guidelines for the management of community acquired pneumonia in Adults. The main objective is to help physicians to make decisions about this disease. The different points that have been developed are: aetiology, diagnosis, treatment and prevention.

Nonresponses and treatment failures with conventional empiric regimens in patients with community-acquired pneumonia

Although most patients with suspected CAP respond to empiric therapy,a small number of patients do not respond in the expected fashion. Age and underlying comorbid conditions have a strong influence on the course of illness. Less common causes of treatment failures include overwhelming infection, antimicrobial resistance, and misdiagnosis. It is a common practice for empiric antimicrobial treatment of CAP to be initiated without microbiologic studies. Clinicians carefully should observe these patients for unusual or slow responses and should be ready to pursue a more extensive search for the cause of treatment failure.

Risk factors of treatment failure in community acquired pneumonia: implications for disease outcome

BACKGROUND

An inadequate response to initial empirical treatment of community acquired pneumonia (CAP) represents a challenge for clinicians and requires early identification and intervention. A study was undertaken to quantify the incidence of failure of empirical treatment in CAP, to identify risk factors for treatment failure, and to determine the implications of treatment failure on the outcome.

METHODS

A prospective multicentre cohort study was performed in 1424 hospitalised patients from 15 hospitals. Early treatment failure (<72 hours), late treatment failure, and in-hospital mortality were recorded.

RESULTS

Treatment failure occurred in 215 patients (15.1%): 134 early failure (62.3%) and 81 late failure (37.7%). The causes were infectious in 86 patients (40%), non-infectious in 34 (15.8%), and undetermined in 95. The independent risk factors associated with treatment failure in a stepwise logistic regression analysis were liver disease, pneumonia risk class, leucopenia, multilobar CAP, pleural effusion, and radiological signs of cavitation. Independent factors associated with a lower risk of treatment failure were influenza vaccination, initial treatment with fluoroquinolones, and chronic obstructive pulmonary disease (COPD). Mortality was significantly higher in patients with treatment failure (25% v 2%). Failure of empirical treatment increased the mortality of CAP 11-fold after adjustment for risk class.

CONCLUSIONS

Although these findings need to be confirmed by randomised studies, they suggest possible interventions to decrease mortality due to CAP.

Diagnosis of infection in sepsis: An evidence-based review

OBJECTIVE

In 2003, critical care and infectious disease experts representing 11 international organizations developed management guidelines for the diagnosis of infection in sepsis that would be of practical use for the bedside clinician, under the auspices of the Surviving Sepsis Campaign, an international effort to increase awareness and improve outcome in severe sepsis.

DESIGN

The process included a modified Delphi method, a consensus conference, several subsequent smaller meetings of subgroups and key individuals, teleconferences, and electronic-based discussion among subgroups and among the entire committee.

METHODS

The modified Delphi methodology used for grading recommendations built on a 2001 publication sponsored by the International Sepsis Forum. We undertook a systematic review of the literature graded along five levels to create recommendation grades from A to E, with A being the highest grade. Pediatric considerations to contrast adult and pediatric management are in the article by Parker et al. on p. S591.

CONCLUSIONS

Obtaining a precise bacteriological diagnosis before starting antibiotic therapy is, when possible, of paramount importance for the success of therapeutic strategy during sepsis. Two to three blood cultures should be performed, preferably from a peripheral vein, without interval between samples to avoid delaying therapy. A quantitative approach is preferred in most cases when possible, in particular for catheter-related infections and ventilator-associated pneumonia. Diagnosing community-acquired pneumonia is complex, and a diagnostic algorithm is proposed. Appropriate samples are indicated during soft tissue and intraabdominal infections, but cultures obtained through the drains are discouraged.

Cost-effectiveness of the pneumococcal vaccine in healthy younger adults

OBJECTIVES

Routine vaccination for Streptococcus pneumoniae has been recommended as a cost-effective measure for elderly and immunocompromised patients, yet no analysis has been performed for healthy younger adults in America. The authors evaluated the cost-effectiveness of the pneumococcal vaccine and determined the net health benefits conferred for the healthy young adult population.

METHODS

The authors developed a decision model to compare the health and economic outcomes of vaccinate versus do not vaccinate for S. pneumoniae.

RESULTS

Vaccinating patients for S. pneumoniae generates benefits that are dependent on incidence rates and the efficacy of the vaccine. In the 22-year-old patient with a pneumonia incidence of 0.3/1000, the vaccine would need to be > 71 percent effective for the vaccination strategy to cost less than $50,000/QALY gained. At an incidence of 0.4/1000, the threshold efficacy is 53 percent, whereas at 0.5/1000 it is 43 percent. In the 35-year-old patient where the incidence of pneumococcal pneumonia is higher (0.85/1000), the vaccine would be cost-effective with an efficacy as low as 30 percent.

CONCLUSIONS

Use of the S. pneumoniae vaccine in young adults would provide modest reductions in pneumonia-associated morbidity and mortality. Vaccination of young adults is moderately expensive unless vaccine efficacy is above 50% to 60%. In 35-year-old adults, use of the vaccine is cost-effective even with moderate efficacy.

Intensified microbiological investigations in adult patients admitted to hospital with lower respiratory tract infections

The objective of this study was to investigate the diagnostic yield of a programme with intensified microbiological investigations in immunocompetent adult patients with lower respiratory tract infections (LRTI). Patients in the study group were included prospectively and consecutively from September 1st 1997 to May 31st 1998 and were compared with a control group from the preceding year. A total of 67 adult patients were included in the study group and they were compared with 122 adult patients in the control group. The study group underwent fibre-optic bronchoscopy (FOB) with bronchoalveolar lavage (BAL). Only 7% in the historic control group were discharged with an aetiological diagnosis of their infections; while the diagnostic yield in the study group increased to 51% of patients. In the study group the presence of new infiltrates on chest X-ray increased the detection of a microbiological aetiology from 37% with no infiltrates to 62% with infiltrates and recent antibiotic therapy reduced the detection of a microbiological cause of infection from 61% in 36 patients who had not received antibiotic therapy to 39% in 31 patients who had received recent antibiotic therapy prior to microbiological sampling. Patients in the study group with known aetiology had higher values of inflammatory markers than patients with unknown aetiology. For Streptococcus pneumoniae infection culture and urine antigen detection were complimentary depending on recent antibiotic therapy since seven of eight culture-positive patients had not received antibiotic therapy within 72 h prior to investigation, while all four patients positive for urine antigens from S. pneumoniae had received antibiotic therapy within 72 h of urine sampling. In conclusion intensified microbiologic investigations increase the diagnostic yield from 7% to 51% of patients in the study group with an aetiologic diagnosis. Routine FOB with BAL had no apparent effect on clinical outcome and seems only justified in selected patients with severe LRTI with infiltrates on chest X-ray and signs of severe inflammation where a high diagnostic yield is achieved.

The pulmonary physician in critical care . 3: critical care management of community acquired pneumonia

Severe community acquired pneumonia carries a high mortality. Early recognition of the severity of the illness, rapid and appropriate resuscitation, targeted antibiotic treatment, and the critical care support of multiple failing organ systems are all important in this group of patients. Only by improving all these aspects of care is it likely that survival will increase.

Nonresolving pneumonia and mimics of pneumonia

Physicians caring for patients with community-acquired pneumonia are often faced with the dilemma of how to approach a patient with slowly resolving or even nonresolving pneumonia. When the radiograph has failed to resolve by 50% in 2 weeks or completely in 4 weeks, the pneumonia should be considered to be nonresolving or slowly resolving. The causes of a nonresolving pneumonia and an approach to the work-up are presented.

An emergency department-based randomized trial of nonbronchoscopic bronchoalveolar lavage for early pathogen identification in severe community-acquired pneumonia

STUDY OBJECTIVES

Many patients with community-acquired pneumonia are treated empirically without an aggressive search for causative pathogens, an approach adopted largely because of the costs and difficulties encountered during efforts to identify the causative organisms. Blood and sputum cultures are not sensitive, and the more invasive techniques of bronchoscopy and lung biopsy are generally time consuming and not cost-effective. The technique of nonbronchoscopic bronchoalveolar lavage (BAL) has been shown to accurately diagnose the causes of nosocomial pneumonia. The purpose of this study was to determine whether an emergency department-based BAL protocol would lead to more frequent isolation of pneumonia pathogens and result in more changes to tailored antibiotic therapy in comparison with standard care.

METHODS

We studied all adult patients admitted with a diagnosis of pneumonia who were tracheally intubated and who had obtainable familial consent in the ED of an urban county hospital from March 1998 to October 1999. Exclusions included antibiotic use within the past 5 days, pneumothorax, hemoptysis, or persistent hypoxia using 100% oxygen. Patients were randomized to standard care versus standard care plus BAL. Blood culture specimens were drawn from all patients before the initiation of antibiotics. All other diagnostic tests were ordered at the discretion of treating physicians. BAL fluid, sputum, and blood culture specimens were tracked, and patient antibiotic course was followed to assess any change in regimen.

RESULTS

Twenty-six of 64 patients evaluated for study participation met all eligibility criteria; 14 patients received standard care, and 12 patients received standard care plus BAL. Pneumonia pathogens were identified in 10 (83.3%) of 12 patients in the BAL group and in 4 (28.6%) of 14 patients in the standard care group (P =.007). Comparing BAL versus non-BAL groups, there was no significant difference in the likelihood of overall antibiotic regimen changes (P =.149), but there was a difference with regard to antibiotic changes made in patients with positive culture test results (P =.026). No major complications occurred with BAL catheterizations.

CONCLUSION

ED-based BAL catheterization allows for early identification of pathogens in severe community-acquired pneumonia, which leads to changes in antibiotic therapy.

Community-acquired pneumonia in patients requiring hospitalization

OBJECTIVE

This study aimed to investigate the microbial aetiology of community-acquired pneumonia (CAP) in patients requiring hospitalization.

METHODOLOGY

A prospective study of consecutive non-immunocompromised patients aged 12 years and above admitted with CAP from August 1997 to May 1999 was undertaken.

RESULTS

Of 127 patients hospitalized for CAP, an aetiological diagnosis was achieved in 53 cases (41.7%). Klebsiella pneumoniae was the most frequently isolated pathogen and caused 10.2% of all the cases, followed by Streptococcus pneumoniae (5.5%), Haemophilus influenzae (5.5%), Mycoplasma pneumoniae (3.9%) and Pseudomonas aeruginosa (3.9%). Gram-negative bacilli were significantly more frequently identified in patients aged 60 years or older and in patients with comorbid illnesses. Twelve of 13 patients who died from CAP had other comorbid illnesses compared to 63 of 114 patients who survived (P = 0.014). Three of eight bacteraemic patients died compared with 10 of 119 non-bacteraemic patients (P = 0.035).

CONCLUSIONS

The microbiology of CAP in patients requiring hospitalization in Malaysia appears to be different from that in Western countries. Gram-negative bacilli were more frequently isolated in older patients and in those with comorbidity. Mortality from CAP is more likely in patients with comorbidity and in those who are bacteraemic.

Are quantitative cultures useful in the diagnosis of hospital-acquired pneumonia?

Noninvasive and invasive tests have been developed and studied for their utility in diagnosing and guiding the treatment of hospital-acquired pneumonia, a condition with an inherently high mortality. Early empiric antibiotic treatment has been shown to reduce mortality, so delaying this treatment until test results are available is not justifiable. Furthermore, tailoring therapy based on results of either noninvasive or invasive tests has not been clearly shown to affect morbidity and mortality. This may be related to quantitative limitations of these tests or possibly to a high false-negative rate in patients who receive early antibiotic treatment and may therefore have suppressed bacterial counts. Results of these tests, however, do influence treatment. It is therefore hoped that they may ultimately provide a rational basis for making therapeutic decisions. In the future, outcomes research should be a part of large-scale clinical trials, and noninvasive and invasive tests should be incorporated into the design in an attempt to provide a better understanding of the value of such tests.

Diagnosis of pneumonia and monitoring of infection eradication

Pneumonia can be classified as community-acquired (CAP) or hospital-acquired (nosocomial). Both are frequent infections that demand a great amount of medical resources. The diagnosis of CAP is based on clinical signs and the presence of a pulmonary infiltrate visible on chest radiograph. For practical purposes, CAP has been classified as typical, with an acute onset in which the most representative microorganism is Streptococccus pneumoniae, and atypical, with a subacute onset (Mycoplasma pneumoniae). Nevertheless, so far no studies have clearly demonstrated the utility of this classification in predicting the aetiology. Guidelines on CAP recommend associating the aetiology of CAP with comorbidity, age and severity. The microbiological diagnosis relies mainly on Gram stain and sputum culture, but this technique has disadvantages such as frequent contamination of the sample with oropharyngeal commensal flora, frequent sterile cultures associated with previous antibiotic treatment, and the fact that approximately 40% of patients are not able to expectorate. Other diagnostic techniques such as blood cultures, serological tests and fibreoptic bronchoscopy must be reserved for patients who are hospitalised, especially if they need admission to an intensive care unit. Compared with CAP, nosocomial pneumonia has major diagnostic problems due to the presence of other diseases able to mimic pneumonia and frequent bacterial colonisation of the lower respiratory tract. Most of the diagnostic techniques produce a high percentage of false-negative and false-positive results. This is especially true for ventilator-associated pneumonia. There is controversy over using a comprehensive aetiological work-up based on bronchoscopic techniques or only on quantitative culture of endotracheal aspiration. By contrast, there is consensus about the importance of the adequacy of empirical antibiotic treatment, since mortality rates are higher in patients who are inadequately treated. Once treatment of pneumonia has begun, it must be maintained for 48 to 72 hours because this is the minimum time to evaluate a clinical response. Antibacterial agents have to be adjusted according to microbiological findings. In nonresponding patients, pneumonia-related complications and the presence of multiresistant micro-organisms or non-covered pathogens must be ruled out.

Impact of BAL in the management of pneumonia with treatment failure: positivity of BAL culture under antibiotic therapy

BACKGROUND

Pneumonia is responsible for 50% of antibiotics prescribed in ICUs. Treatment failure, ie, absence of improvement or clinical deterioration under antibiotic therapy, presents a dilemma to physicians. BAL is an invasive method validated for etiologic diagnosis in pneumonia.

STUDY OBJECTIVE

To evaluate in ICU patients the impact of BAL in the etiologic diagnosis, treatment, and outcome of pneumonia with treatment failure.

DESIGN

Prospective clinical study.

SETTING

Nonsurgical, medical ICU of a university hospital in Brazil.

PATIENTS AND PARTICIPANTS

Sixty-two episodes of pneumonia treated for at least 72 h without clinical improvement in 53 patients hospitalized for diverse clinical emergencies. Mean duration of hospitalization was 14.2 days. Mean duration of previous antibiotic therapy was 11.4 days.

INTERVENTIONS

Bronchoscopy and BAL were performed in each episode. BAL fluid was cultivated for aerobic and anaerobic bacteria; the cutoff considered positive was 10(4) cfu/mL; 10(3) cfu/mL was also analyzed if under treatment. Pneumocystis carinii, fungi, Legionella spp, and Mycobacterium spp were also researched.

MEASUREMENTS AND RESULTS

Fifty-eight of 62 BAL were performed under antibiotics. The results showed positivity in 45 of 62 (72.6%); 42 of the 45 positive episodes (93.3%) had > 10(4) cfu/mL. The three cases with between 10(3) and 10(4) cfu/mL were considered positive and were treated according to BAL cultures. The main agents were Acinetobacter baumannii (37.1%), Pseudomonas aeruginosa (17.7%), and methicillin-resistant Staphylococcus aureus (MRSA; 16.1%); 46.7% of the episodes (21 of 45) were polymicrobial. BAL results directed a change of therapy in 34 episodes (54.8%). Overall mortality was 43.5%. There was no difference in mortality among positives, negatives, and patients who changed therapy guided by BAL culture.

CONCLUSIONS

(1) BAL fluid examination was positive in 45 of 62 episodes (72.6%), with 58 of 62 BAL performed under antibiotics. This suggests that BAL may be a sensitive diagnostic method for treatment failures of clinically diagnosed pneumonias, even if performed under antibiotics; (2) the main pathogens in our study were A baumannii, P aeruginosa, and MRSA, and approximately 45% of infections were polymicrobial; (3) BAL culture results directed a change of therapy in 75.6% of positive episodes (34 of 45) and in 54.8% of all episodes of treatment failure (34 of 62); and (4) there was no difference in mortality among positives, negatives, and patients who changed therapy guided by BAL culture.

Summary of Canadian guidelines for the initial management of community-acquired pneumonia: an evidence-based update by the Canadian Infectious Disease Society and the Canadian Thoracic Society

Community-acquired pneumonia (CAP) is a serious illness with a significant impact on individual patients and society as a whole. Over the past several years, there have been significant advances in the knowledge and understanding of the etiology of the disease, and an appreciation of problems such as mixed infections and increasing antimicrobial resistance. The development of additional fluoroquinolone agents with enhanced activity against Streptococcus pneumoniae has been important as well.It was decided that the time had come to update and modify the previous CAP guidelines, which were published in 1993. The current guidelines represent a joint effort by the Canadian Infectious Diseases Society and the Canadian Thoracic Society, and they address the etiology, diagnosis and initial management of CAP. The diagnostic section is based on the site of care, and the treatment section is organized according to whether one is dealing with outpatients, inpatients or nursing home patients.

Antimicrobial treatment failures in patients with community-acquired pneumonia: causes and prognostic implications

The aim of the study was to determine the causes and prognostic implications of antimicrobial treatment failures in patients with nonresponding and progressive life-threatening, community-acquired pneumonia. Forty-nine patients hospitalized with a presumptive diagnosis of community-acquired pneumonia during a 16-mo period, failure to respond to antimicrobial treatment, and documented repeated microbial investigation >/= 72 h after initiation of in-hospital antimicrobial treatment were recorded. A definite etiology of treatment failure could be established in 32 of 49 (65%) patients, and nine additional patients (18%) had a probable etiology. Treatment failures were mainly infectious in origin and included primary, persistent, and nosocomial infections (n = 10 [19%], 13 [24%], and 11 [20%] of causes, respectively). Definite but not probable persistent infections were mostly due to microbial resistance to the administered initial empiric antimicrobial treatment. Nosocomial infections were particularly frequent in patients with progressive pneumonia. Definite persistent infections and nosocomial infections had the highest associated mortality rates (75 and 88%, respectively). Nosocomial pneumonia was the only cause of treatment failure independently associated with death in multivariate analysis (RR, 16.7; 95% CI, 1.4 to 194.9; p = 0.03). We conclude that the detection of microbial resistance and the diagnosis of nosocomial pneumonia are the two major challenges in hospitalized patients with community-acquired pneumonia who do not respond to initial antimicrobial treatment. In order to establish these potentially life-threatening etiologies, a regular microbial reinvestigation seems mandatory for all patients presenting with antimicrobial treatment failures.

Accuracy and precision of quantitative calibrated loops in transfer of bronchoalveolar lavage fluid

Quantitative cultures of bronchoalveolar lavage (BAL) fluid are important in the diagnosis of ventilator-associated pneumonia, and calibrated loops are commonly used to set up these cultures. In this study, the performances of calibrated 0.010- and 0.001-ml loops in the transfer of BAL fluid were determined. Five loops of one lot from seven manufacturers were tested. Calibrations were performed by the gravimetric method (0.010-ml loops) and the colorimetric method (0.001-ml loops). Most of the 0.010-ml loops displayed a precision that was less than 10%, but six of them showed very poor accuracies as they transferred a deficiency (nichrome loops) or an excess (disposable loops) of BAL fluid that exceeded +/-10%. The mean maximum and minimum BAL fluid volumes delivered by the 0.010-ml loops differed by a factor 3. The 0.001-ml loops displayed acceptable precision. Five of them showed inaccuracies of </=+/-10%, and mean maximum and minimum BAL fluid volumes had a range of a factor of 2. For all loops, the volumes of BAL fluid sampled were larger than the volumes of reagent-grade water sampled. Results of the colony counting experiments confirmed these findings and revealed a high intra-assay variability for the 0.001-ml loops. We conclude that, when BAL fluid samples are cultured with calibrated loops, (i) proper verification of the calibration of these loops is mandatory, (ii) calibrations should be performed with BAL fluid as the test solution, and (iii) borderline quantitative culture results should be interpreted with knowledge of the inaccuracy values of these loops.

Management of patients with community-acquired pneumonia in a primary care hospital: a critical evaluation

The aim of the study was to evaluate routine management of patients with community-acquired pneumonia (CAP) with regard to severity patterns, diagnostic approaches and results, as well as initial empiric antimicrobial treatment and its impact on outcome. Two hundred and thirty-two consecutive patients with CAP admitted to a primary care hospital were studied prospectively. Patients were classified according to Fine's severity score. Severe pneumonia was defined as admission at the ICU. Diagnostic approaches and initial antimicrobial treatment were judged according to the guidelines of the European Respiratory Society (ERS). Fifty-five patients (24%) had mild, 156 (67%) moderate, and 21 (9%) severe CAP. At least one microbial examination was performed in 124 patients (54%). There was no association between microbial investigation and severity of CAP. Inadequate initial antimicrobial treatment was significantly more frequent in severe (18/21, 86%), than in mild (5/55, 9%) and moderate CAP (39/156, 25%, P < 0.0001). Conversely, antimicrobial overtreatment occurred significantly more often in mild (30/55, 55%) and moderate (77/156, 49%) than in severe CAP (0/21, 0%, P < 0.0001). Inadequate initial antimicrobial treatment was more frequent in non-responders [18/62 (29%) vs. 31/170, (18%), RR 1.6 95% CI 0.9-2.6, P = 0.07] and was associated with a longer duration of hospitalization (17 +/- 11 vs. 14 +/- 8 days, P = 0.03). Mortality was not affected by inadequate initial antimicrobial treatment [5/62 (8%) vs. 10/170 (6%), RR 1.4 95% CI 0.5-3.9, P=0.55]. Principal conceptual weaknesses which might be subject to intervention were (1) the hospitalization of patients with mild pneumonia at low risk of mortality; (2) the lack of association between microbial investigation and severity of CAP; (3) antimicrobial overtreatment of patients with non-severe CAP; and (4) inadequate antimicrobial treatment with increased number of primary treatment failures and duration of hospitalization.