The value of routine microbial investigation in community-acquired pneumonia

A Haemophilus sp. dominates the microbiota of sputum from UK adults with non-severe community acquired pneumonia and chronic lung disease

The demographics and comorbidities of patients with community acquired pneumonia (CAP) vary enormously but stratified treatment is difficult because aetiological studies have failed to comprehensively identify the pathogens. Our aim was to describe the bacterial microbiota of CAP and relate these to clinical characteristics in order to inform future trials of treatment stratified by co-morbidity. CAP patients were prospectively recruited at two UK hospitals. We used 16S rRNA gene sequencing to identify the dominant bacteria in sputum and compositional data analysis to determine associations with patient characteristics. We analysed sputum samples from 77 patients and found a Streptococcus sp. and a Haemophilus sp. were the most relatively abundant pathogens. The Haemophilus sp. was more likely to be dominant in patients with pre-existing lung disease, and its relative abundance was associated with qPCR levels of Haemophilus influenzae. The most abundant Streptococcus sp. was associated with qPCR levels of Streptococcus pneumoniae but dominance could not be predicted from clinical characteristics. These data suggest chronic lung disease influences the microbiota of sputum in patients with CAP. This finding could inform a trial of stratifying empirical CAP antibiotics to target Haemophilus spp. in addition to Streptococcus spp. in those with chronic lung disease.

BreathDx - molecular analysis of exhaled breath as a diagnostic test for ventilator-associated pneumonia: protocol for a European multicentre observational study

BACKGROUND

The diagnosis of ventilator-associated pneumonia (VAP) remains time-consuming and costly, the clinical tools lack specificity and a bedside test to exclude infection in suspected patients is unavailable. Breath contains hundreds to thousands of volatile organic compounds (VOCs) that result from host and microbial metabolism as well as the environment. The present study aims to use breath VOC analysis to develop a model that can discriminate between patients who have positive cultures and who have negative cultures with a high sensitivity.

METHODS/DESIGN

The Molecular Analysis of Exhaled Breath as Diagnostic Test for Ventilator-Associated Pneumonia (BreathDx) study is a multicentre observational study. Breath and bronchial lavage samples will be collected from 100 and 53 intubated and ventilated patients suspected of VAP. Breath will be analysed using Thermal Desorption - Gas Chromatography - Mass Spectrometry (TD-GC-MS). The primary endpoint is the accuracy of cross-validated prediction for positive respiratory cultures in patients that are suspected of VAP, with a sensitivity of at least 99% (high negative predictive value).

DISCUSSION

To our knowledge, BreathDx is the first study powered to investigate whether molecular analysis of breath can be used to classify suspected VAP patients with and without positive microbiological cultures with 99% sensitivity.

TRIAL REGISTRATION

UKCRN ID number 19086, registered May 2015; as well as registration at www.trialregister.nl under the acronym 'BreathDx' with trial ID number NTR 6114 (retrospectively registered on 28 October 2016).

Azithromycin for acute lower respiratory tract infections

BACKGROUND

Acute lower respiratory tract infections (LRTI) range from acute bronchitis and acute exacerbations of chronic bronchitis to pneumonia. Approximately five million people die from acute respiratory tract infections annually. Among these, pneumonia represents the most frequent cause of mortality, hospitalisation and medical consultation. Azithromycin is a macrolide antibiotic, structurally modified from erythromycin and noted for its activity against some gram-negative organisms associated with respiratory tract infections, particularly Haemophilus influenzae (H. influenzae).

OBJECTIVES

To compare the effectiveness of azithromycin to amoxycillin or amoxycillin/clavulanic acid (amoxyclav) in the treatment of LRTI, in terms of clinical failure, incidence of adverse events and microbial eradication.

SEARCH METHODS

We searched CENTRAL (2014, Issue 10), MEDLINE (January 1966 to October week 4, 2014) and EMBASE (January 1974 to November 2014).

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs, comparing azithromycin to amoxycillin or amoxycillin/clavulanic acid in participants with clinical evidence of an acute LRTI, such as acute bronchitis, pneumonia and acute exacerbation of chronic bronchitis.

DATA COLLECTION AND ANALYSIS

The review authors independently assessed all potential studies identified from the searches for methodological quality. We extracted and analysed relevant data separately. We resolved discrepancies through discussion. We initially pooled all types of acute LRTI in the meta-analyses. We investigated the heterogeneity of results using the forest plot and Chi(2) test. We also used the index of the I(2) statistic to measure inconsistent results among trials. We conducted subgroup and sensitivity analyses.

MAIN RESULTS

We included 16 trials involving 2648 participants. We were able to analyse 15 of the trials with 2496 participants. The pooled analysis of all the trials showed that there was no significant difference in the incidence of clinical failure on about days 10 to 14 between the two groups (risk ratio (RR), random-effects 1.09; 95% confidence interval (CI) 0.64 to 1.85). A subgroup analysis in trials with acute bronchitis participants showed significantly lower clinical failure in the azithromycin group compared to amoxycillin or amoxyclav (RR random-effects 0.63; 95% CI 0.45 to 0.88). A sensitivity analysis showed a non-significant reduction in clinical failure in azithromycin-treated participants (RR 0.55; 95% CI 0.25 to 1.21) in three adequately concealed studies, compared to RR 1.32; 95% CI 0.70 to 2.49 in 12 studies with inadequate concealment. Twelve trials reported the incidence of microbial eradication and there was no significant difference between the two groups (RR 0.95; 95% CI 0.87 to 1.03). The reduction of adverse events in the azithromycin group was RR 0.76 (95% CI 0.57 to 1.00).

AUTHORS' CONCLUSIONS

There is unclear evidence that azithromycin is superior to amoxycillin or amoxyclav in treating acute LRTI. In patients with acute bronchitis of a suspected bacterial cause, azithromycin tends to be more effective in terms of lower incidence of treatment failure and adverse events than amoxycillin or amoxyclav. However, most studies were of unclear methodological quality and had small sample sizes; future trials of high methodological quality and adequate sizes are needed.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Risk factors for aspiration in community-acquired pneumonia: analysis of a hospitalized UK cohort

BACKGROUND

There is a move toward finding clinically useful "phenotypes" in community-acquired pneumonia: groups of patients displaying distinct clinical characteristics, microbiology, and prognosis. Aspiration pneumonia is an intuitive clinical phenotype; however, to date there are no recognized diagnostic criteria, and data regarding outcomes in suspected aspiration are limited.

METHODS

An observational study of 1348 patients hospitalized with community-acquired pneumonia in the United Kingdom examined both short- and long-term outcomes for patients at risk of aspiration pneumonia. Patients were defined as "at risk" in the presence of chronic neurologic disorders, esophageal disorders and dysphagia, impaired conscious level, vomiting, or witnessed aspiration. The primary outcome was 30-day mortality. Secondary outcomes included 1-year mortality, readmissions, and recurrent pneumonia within 1 year.

RESULTS

Some 13.8% of the cohort were classified as "at risk of aspiration." These patients were older (median age, 74 years [interquartile range, 60-84] vs 66 years [interquartile range, 49-77]; P < .0001) and more likely to have comorbidities (chronic liver disease 11.3% vs 3.7%, P < .0001; congestive heart failure 28% vs 17.1%, P = .0004; and stroke 26.9% vs 9.5%, P < .0001). Patients at risk of aspiration pneumonia had a poorer short-term outcome (30-day mortality 17.2% vs 7.7%, P < .0001), but after adjusting for their greater severity of illness and comorbidities this difference was not significant (odds ratio 1.05; 95% confidence interval [CI], 0.63-1.76; P = .8). However, patients with aspiration risk factors were at greater risk of poor long-term outcomes with increased 1-year mortality (hazard ratio [HR], 1.73; 95% CI, 1.15-2.58), increased risk of rehospitalization (HR, 1.52; 95% CI, 1.21-1.91), and a strong association with recurrent admissions with pneumonia (HR, 3.13; 95% CI, 2.05-4.78) after multivariable adjustment.

CONCLUSIONS

Using risk factors to identify patients at risk of aspiration pneumonia identifies a distinct clinically useful phenotype of patients with greater severity of disease and poorer long-term outcomes.

Macrolide-based regimens in absence of bacterial co-infection in critically ill H1N1 patients with primary viral pneumonia

PURPOSE

To determine whether macrolide-based treatment is associated with mortality in critically ill H1N1 patients with primary viral pneumonia.

METHODS

Secondary analysis of a prospective, observational, multicenter study conducted across 148 Intensive Care Units (ICU) in Spain.

RESULTS

Primary viral pneumonia was present in 733 ICU patients with pandemic influenza A (H1N1) virus infection with severe respiratory failure. Macrolide-based treatment was administered to 190 (25.9 %) patients. Patients who received macrolides had chronic obstructive pulmonary disease more often, lower severity on admission (APACHE II score on ICU admission (13.1 ± 6.8 vs. 14.4 ± 7.4 points, p < 0.05), and multiple organ dysfunction syndrome less often (23.4 vs. 30.1 %, p < 0.05). Length of ICU stay in survivors was not significantly different in patients who received macrolides compared to patients who did not (10 (IQR 4-20) vs. 10 (IQR 5-20), p = 0.9). ICU mortality was 24.1 % (n = 177). Patients with macrolide-based treatment had lower ICU mortality in the univariate analysis (19.2 vs. 28.1 %, p = 0.02); however, a propensity score analysis showed no effect of macrolide-based treatment on ICU mortality (OR = 0.87; 95 % CI 0.55-1.37, p = 0.5). Moreover, the sensitivity analysis revealed very similar results (OR = 0.91; 95 % CI 0.58-1.44, p = 0.7). A separate analysis of patients under mechanical ventilation yielded similar results (OR = 0.77; 95 % CI 0.44-1.35, p = 0.4).

CONCLUSION

Our results suggest that macrolide-based treatment was not associated with improved survival in critically ill H1N1 patients with primary viral pneumonia.

Low utilisation of diagnostic microbiology for community acquired pneumonia in regional Victoria

Aims

Diagnostic microbiology for community acquired pneumonia (CAP) provides useful information for patient management, infection control and epidemiological surveillance. Newer techniques enhance that information and the time interval for obtaining results. An audit of diagnostic microbiology utilisation, microbiological aetiology, and influence of results on prescribing practices in CAP in a regional Australian hospital setting was performed.

Methods

Clinical, microbiological and outcome data were collected by medical record review of patients discharged from Ballarat Hospital with a diagnosis of CAP over a 12 month period.

Results

Of 184 identified CAP episodes, 47 (25.5%) had no diagnostic microbiology performed. Respiratory virus polymerase chain reaction (PCR) was rarely performed (2.7% of all episodes). Acute serology was frequently requested, however paired acute and convalescent serology was infrequently performed (5/75 testing episodes; 6.7%). CAP severity was not correlated with microbiological investigation intensity. The most common pathogens identified were Streptococcus pneumoniae and Mycoplasma pneumoniae (5.4% and 2.2%, respectively). Diagnostic testing appeared to rarely influence antimicrobial prescribing.

Conclusions

In this setting, diagnostic microbiological tests such as respiratory virus PCR and urinary antigen tests are under-utilised. In contrast, sputum and serological investigations are commonly requested, however rarely influence practice. Interventions to facilitate efficient usage of diagnostic microbiology are required.

Observations from a multicentre study on the use of the sputum specimen in patients hospitalized with community-acquired pneumonia

OBJECTIVE

To describe the use of sputum Gram stain and culture in patients with community-acquired pneumonia (CAP) and to determine the factors that are associated with obtaining sputum for culture.

TYPE OF STUDY

Prospective observational cohort study of patients hospitalized for treatment of CAP at four medical institutions in three geographic locations.

MAIN MEASUREMENTS

Results of Gram stain and culture of sputum; comparison of patients who had sputum processed for culture within 24 h of admission with those who did not have such a specimen processed during the first week of hospitalization; and the results of investigator assignment of etiology of pneumonia according to predefined criteria.

RESULTS

Four hundred and seventy-eight of 1339 (36%) patients had a sputum specimen processed for culture within 24 h of admission. Patients who had a sputum specimen processed within 24 h of admission were more likely to be hospitalized at the Boston site (odds ratio [OR] 20.6) or Pittsburgh sites (3.4) and to have current sputum production, chronic obstructive lung disease and moderate or large amount of sputum. Female sex (0.4), neutropenia (0.05), and do not resuscitate status (0.36) were important predictors of failure to have a sputum processed for culture. The rate of Streptococcus pneumoniae isolation was highest in Boston, 53 of 269 (19.3 %) patients (P<0.001) compared with the other sites; Moraxella catarrhalis was isolated only at the Boston site. Sputum culture results served as the basis for the assignment of an etiological diagnosis of the pneumonia by investigators in 67% of 397 patients.

CONCLUSIONS

Sputum is not processed for culture in the majority of patients with CAP. The factors that determine whether sputum is processed for culture within 24 h of admission are site of care and a variety of patient factors. Common respiratory pathogens when present in sputum culture tend to be used to assign an etiological diagnosis. A positive sputum culture result appears not to result in a more favourable outcome.

Blood cultures in ambulatory patients who are discharged from emergency with community-acquired pneumonia

OBJECTIVES

To determine the factors that predict whether or not ambulatory patients with community-acquired pneumonia (CAP) treated in an emergency room (ER) setting will have blood cultures drawn and the factors that predict a positive blood culture.

METHODS

Prospective observational study of all patients with a diagnosis of CAP, as made by an ER physician, who presented to any of seven Edmonton-area ERs over a two-year period.

RESULTS

Seven hundred ninety-three (19.2%) of 4124 patients with CAP had blood cultures drawn. The site-specific blood culture rates ranged from 7.8% to 25% (P<0.001); 41 of 793 (5.1%) were positive. Streptococcus pneumoniae accounted for 58.5% of the isolates while Staphylococcus aureus and Escherichia coli each accounted for 14.6%, or six patients each. Only two of the 24 patients with S pneumoniae bacteremia were subsequently admitted to hospital while all six of the patients with S aureus were admitted. Only one of the six patients with E coli bacteremia was treated at home. No factors were predictive of positive blood cultures on multivariate analysis.

CONCLUSIONS

Physicians are selective in ordering blood cultures on patients with ambulatory pneumonia who present to an ER, and the positivity rate of 5.1% is quite high. No factors are predictive of positive blood cultures on multivariate analysis, thus clinical judgment has to prevail in the decision to perform blood cultures. Breakthrough bacteremia can occur with microorganisms susceptible to the antibiotics that the patient is receiving.

Community-acquired respiratory coinfection in critically ill patients with pandemic 2009 influenza A(H1N1) virus

BACKGROUND

Little is known about the impact of community-acquired respiratory coinfection in patients with pandemic 2009 influenza A(H1N1) virus infection.

METHODS

This was a prospective, observational, multicenter study conducted in 148 Spanish ICUs.

RESULTS

Severe respiratory syndrome was present in 645 ICU patients. Coinfection occurred in 113 (17.5%) of patients. Streptococcus pneumoniae (in 62 patients [54.8%]) was identified as the most prevalent bacteria. Patients with coinfection at ICU admission were older (47.5±15.7 vs 43.8±14.2 years, P<.05) and presented a higher APACHE (Acute Physiology and Chronic Health Evaluation) II score (16.1±7.3 vs 13.3±7.1, P<.05) and Sequential Organ Failure Assessment (SOFA) score (7.0±3.8 vs 5.2±3.5, P<.05). No differences in comorbidities were observed. Patients who had coinfection required vasopressors (63.7% vs 39.3%, P<.05) and invasive mechanical ventilation (69% vs 58.5%, P<.05) more frequently. ICU length of stay was 3 days longer in patients who had coinfection than in patients who did not (11 [interquartile range, 5-23] vs 8 [interquartile range 4-17], P=.01). Coinfection was associated with increased ICU mortality (26.2% vs 15.5%; OR, 1.94; 95% CI, 1.21-3.09), but Cox regression analysis adjusted by potential confounders did not confirm a significant association between coinfection and ICU mortality.

CONCLUSIONS

During the 2009 pandemics, the role played by bacterial coinfection in bringing patients to the ICU was not clear, S pneumoniae being the most common pathogen. This work provides clear evidence that bacterial coinfection is a contributor to increased consumption of health resources by critical patients infected with the virus and is the virus that causes critical illness in the vast majority of cases.

Clinical policy: critical issues in the management of adult patients presenting to the emergency department with community-acquired pneumonia

This clinical policy from the American College of Emergency Physicians focuses on critical issues concerning the management of adult patients presenting to the emergency department (ED)with community-acquired pneumonia. It is an update of the 2001 clinical policy for the management and risk stratification of adult patients presenting to the ED with community-acquired pneumonia. A subcommittee reviewed the current literature to derive evidence-based recommendations to help answer the following questions: (1) Are routine blood cultures indicated in patients admitted with community-acquired pneumonia? (2) In adult patients with community-acquired pneumonia without severe sepsis, is there a benefit in mortality or morbidity from the administration of antibiotics within aspecific time course? The evidence was graded and recommendations were given based on the strength of evidence.

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

BACKGROUND

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

PURPOSE

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

DATA SOURCES

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

STUDY SELECTION

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

DATA EXTRACTION

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

DATA SYNTHESIS

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

CONCLUSIONS

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

Sputum examination in the clinical management of community-acquired pneumonia

OBJECTIVE

To evaluate the frequency of the use of sputum examination in the clinical management of community-acquired pneumonia (CAP) in a general hospital and to determine whether its use has an impact on mortality.

METHODS

The medical records of CAP patients treated as inpatients between May and November of 2004 at the Nossa Senhora da Conceição Hospital, located in Porto Alegre, Brazil, were reviewed regarding the following aspects: age; gender; severity of pneumonia (Fine score); presence of sputum; sputum bacteriology; treatment history; change in treatment; and mortality.

RESULTS

A total of 274 CAP patients (134 males and 140 females) were evaluated. Using the Fine score to quantify severity, we classified 79 (28.8%) of those 274 patients as class II, 45 (16.4%) as class III, 97 (35.4%) as class IV, and 53 (19.3%) as class V. Sputum examination was carried out in 92 patients (33.6%). A valid sample was obtained in 37 cases (13.5%), and an etiological diagnosis was obtained in 26 (9.5%), resulting in a change of treatment in only 9 cases (3.3%). Overall mortality was 18.6%. Advanced age (above 65), CAP severity, and dry cough were associated with an increase in the mortality rate. Sputum examination did not alter any clinical outcome or have any influence on mortality.

CONCLUSION

Sputum examination was used in a minority of patients and was not associated with any noticeable benefit in the clinical management of patients with CAP treated in a hospital setting.

Azithromycin for acute lower respiratory tract infections

BACKGROUND

Acute lower respiratory tract infections (LRTI) range from acute bronchitis and acute exacerbations of chronic bronchitis to pneumonia. Approximately five million people die of acute respiratory tract infections annually. Among these, pneumonia represents the most frequent cause of mortality, hospitalization and medical consultation. Azithromycin is a new macrolide antibiotic, structurally modified from erythromycin and noted for its activity against some gram-negative organisms associated with respiratory tract infections, particularly Haemophilus influenzae (H. influenzae).

OBJECTIVES

To compare the effectiveness of azithromycin to amoxycillin or amoxycillin/clavulanic acid (amoxyclav) in the treatment of LRTI, in terms of clinical failure, incidence of adverse events and microbial eradication.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007 Issue 2), MEDLINE (January 1966 to July 2007), and EMBASE (January 1974 to July 2007).

SELECTION CRITERIA

Randomized and quasi-randomized controlled trials, comparing azithromycin to amoxycillin or amoxycillin/clavulanic acid in participants with clinical evidence of acute LRTI: acute bronchitis, pneumonia, and acute exacerbation of chronic bronchitis were studied.

DATA COLLECTION AND ANALYSIS

The criteria for assessing study quality were generation of allocation sequence, concealment of treatment allocation, blinding, and completeness of the trial. All types of acute LRTI were initially pooled in the meta-analyses. The heterogeneity of results was investigated by the forest plot and Chi-square test. Index of I-square (I(2)) was also used to measure inconsistent results among trials. Subgroup and sensitivity analyses were conducted.

MAIN RESULTS

Fifteen trials were analysed. The pooled analysis of all trials showed that there was no significant difference in the incidence of clinical failure on about day 10 to 14 between the two groups (relative risk (RR), random-effects 1.09; 95% confidence interval (CI) 0.64 to 1.85). Sensitivity analysis showed a reduction of clinical failure in azithromycin-treated participants (RR 0.55; 95% CI 0.25 to 1.21) in three adequately concealed studies, compared to RR 1.32; 95% CI 0.70 to 2.49 in 12 studies with inadequate concealment. Twelve trials reported the incidence of microbial eradication and there was no significant difference between the two groups (RR 0.95; 95% CI 0.87 to 1.03). The reduction of adverse events in the azithromycin group was RR 0.76 (95% CI 0.57 to 1.00).

AUTHORS' CONCLUSIONS

There is unclear evidence that azithromycin is superior to amoxicillin or amoxyclav in treating acute LRTI. In patients with acute bronchitis of a suspected bacterial cause, azithromycin tends to be more effective in terms of lower incidence of treatment failure and adverse events than amoxicillin or amoxyclav. Future trials of high methodological quality are needed.

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.

How Nova Scotia general practitioners choose antibiotics for the empirical treatment of community-acquired pneumonia

OBJECTIVE

To gain an understanding of how physicians in general practice choose antibiotics for the empirical treatment of community-acquired pneumonia (CAP).

DESIGN

Questionnaire with three sample cases of CAP and a knowledge assessment (mailed to half of the physicians).

POPULATION STUDIED

Nova Scotia family physicians.

RESULTS

One hundred and eighty-four of the 841 (21.9%) physicians who were mailed a questionnaire responded. A knowledge assessment showed satisfactory knowledge except in two areas - an overestimation of the prevalence of penicillin-resistant Streptococcus pneumoniae in Nova Scotia and the view that ciprofloxacin was an effective antibiotic for the treatment of CAP (42% of physicians). As the complexity of the case increased, there was decreasing consensus regarding the choice of antibiotic therapy and a decline in prescribing according to guidelines for the treatment of CAP. Also, as the complexity of the cases increased, it became increasingly difficult to discern a decision-making strategy. For the simplest case - a 17-year-old male with presumed Mycoplasma pneumoniae pneumonia - physician factors (age, family practice training), desire to target specific pathogens, and concern with resistance and side effects affected the choice of antibiotic. However, for the most complex case - a 45-year-old female with severe pneumonia - familiarity with such a case was the only significant factor and led to treatment with a combination of antibiotics designed to treat both typical and atypical pathogens.

CONCLUSIONS

For uncomplicated cases of CAP, physician factors, desire to treat specific pathogens and concern with resistance affect the choice of antibiotic therapy. For complex cases, familiarity with such cases was the only factor that influenced choice of antibiotic therapy.

Pneumonia: update on diagnosis and management

Prompt diagnosis and management of community acquired pneumonia saves lives. This article summarises the latest key recommendations in the management of pneumonia and is intended for junior doctors managing this common condition

Epidemiological survey on incidence and treatment of community acquired pneumonia in Italy

STUDY OBJECTIVES

To estimate annual incidence of community acquired pneumonia (CAP) in an Italian general population sample.

DESIGN AND PARTICIPANTS

Two hundred and eighty-seven family practitioners (64.6% of those selected) recorded suspected or ascertained CAP cases for 1 year. Information on smoking habit, respiratory symptoms and signs, co-morbidity, antibiotic and corticosteroid therapy, hospitalization, mortality and recovery were obtained.

RESULTS

Six hundred and ninety-nine case forms were collected (53.1% females, mean age 59.6+/-19.5, 20.6% smokers). CAP incidence rates per 1000 population were: 1.69 in men vs. 1.71 in women; 2.33 in the North vs. 1.29 in the Centre-South of Italy; between 0.73 in 14-, and 3.34 in 64+year-old subjects. Main symptoms and signs were cough (73.3%), crackles (72.8%), dullness (57.3%), asthenia (53.4%). 59.5% of subjects had concurrent diseases, mostly cardiac and respiratory. 77.2% of cases had chest X-ray (with parenchymal density in 90.6%). Phlegm microbiological examination was performed in 12.8% of cases. First choice antibiotics were cephalosporins (45.8%), macrolides (20.2%), other beta-lactams (18.6%), and fluoroquinolones (12.2%). Rates of hospitalization and of mortality were 31.8% and 6.0%, respectively.

CONCLUSION

This study confirmed that the annual CAP incidence rate in the general population of South Europe is about 2 per 1000 population and showed a wide choice of antibiotic treatment.

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.

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.

Do emergency department blood cultures change practice in patients with pneumonia?

STUDY OBJECTIVE

Although it is considered standard of care to obtain blood cultures on patients hospitalized for pneumonia, several studies have questioned the utility and cost-effectiveness of this practice. The objective of this study is to determine the impact of emergency department (ED) blood cultures on antimicrobial therapy for patients with pneumonia.

METHODS

We performed a prospective, observational, cohort study of consecutive adult (age > or =18 years) patients treated at an urban university ED between February 1, 2000 and February 1, 2001. Inclusion criteria were radiographic evidence of pneumonia, clinical evidence of pneumonia, and blood culture obtained. Blood cultures were classified as positive, negative, or contaminant based on previously established criteria. Additionally, data were collected on antimicrobial sensitivities, empiric antibiotic therapy, antibiotic changes, and reasons for changes.

RESULTS

There were 3,926 ED visits with blood cultures obtained for any reason, of which 3,762 (96%) were available for review. Of these, 414 of 3,762 (11%) patients met pneumonia study inclusion criteria, and blood cultures identified 29 of 414 (7.0%) patients with true bacteremia. In the 414 patients, blood culture results altered therapy for 15 patients (3.6%) with suspected pneumonia, of which 11 (2.7%) patients had their coverage narrowed; only 4 (1.0%) patients had their coverage broadened because of resistance to empiric therapy. For the 11 patients with bacteremia whose therapy was not altered, culture results actually supported narrowing therapy in 8 (1.9%) cases, but this was not done.

CONCLUSION

Blood cultures rarely altered therapy for patients presenting to the ED with pneumonia. More discriminatory blood culture use may potentially reduce resource utilization.

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.

Etiology and outcomes of veterans with spinal cord injury and disorders hospitalized with community-acquired pneumonia

OBJECTIVE

To determine whether documentation of a causative organism for community-acquired pneumonia (CAP) is associated with outcomes, including mortality and length of stay (LOS), in hospitalized veterans with spinal cord injuries and disorders (SCI&D).

DESIGN

Retrospective cohort study.

SETTING

Patients with SCI&D admitted with CAP to any Veterans Affairs medical center between September 1998 and October 2000.

PARTICIPANTS

Hospital administrative data on 260 patients with SCI&D and a CAP diagnosis.

INTERVENTIONS

Not applicable.

MAIN OUTCOMES MEASURES

All-cause, 30-day mortality and hospital LOS.

RESULTS

An organism was documented by International Classification of Diseases, 9th Revision , discharge codes in 24% of cases. Streptococcus pneumoniae and Pseudomonas aeruginosa accounted for 32% and 21%, respectively, of the identified bacterial pathogens. The overall mortality rate was 8.5%. No significant association was found between etiologic diagnosis of CAP and 30-day mortality. Lower mortality was associated with treatment at a designated SCI center (relative risk=.35; confidence interval, .12-.99). Pathogen-based CAP diagnosis was significantly associated with longer LOS (adjusted r 2 =.023, P =.024).

CONCLUSIONS

There was no association between etiologic diagnosis of CAP and 30-day mortality among people with SCI&D. Documentation of CAP etiology was associated with the variance in LOS. Pneumococcal vaccination and antibiotic therapy with antipseudomonal activity may be particularly prudent in these patients given the high frequency of these pathogens among SCI&D patients with CAP.

De-escalation therapy in ventilator-associated pneumonia

OBJECTIVE

To evaluate de-escalation of antibiotic therapy in patients with ventilator-associated pneumonia.

DESIGN

Prospective observational study during a 43-month period.

SETTING

Medical-surgical intensive care unit.

PATIENTS

One hundred and fifteen patients admitted to the intensive care unit with clinical diagnosis of ventilator-associated pneumonia. All the episodes of ventilator-associated pneumonia received initial broad-spectrum coverage followed by reevaluation according to clinical response and microbiology. Quantitative cultures obtained by bronchoscopic examination or tracheal aspirates were used to modify therapy.

INTERVENTIONS

: None.

MEASUREMENTS AND MAIN RESULTS

One hundred and twenty-one episodes of ventilator-associated pneumonia were diagnosed. Change of therapy was documented in 56.2%, including de-escalation (the most frequent cause) in 31.4% (increasing to 38% if isolates were sensitive). Overall intensive care unit mortality rate was 32.2%. Inappropriate antibiotic therapy was identified in 9% of cases and was associated with 14.4% excess intensive care unit mortality. Quantitative tracheal aspirates and bronchoscopic samples (58 protected specimen brush and three bronchoalveolar lavage) were associated with 32.7% and 29.5% intensive care unit mortality and 29.3% and 34.4% de-escalation rate. De-escalation was lower (p < .05) in the presence of nonfermenting Gram-negative bacillus (2.7% vs. 49.3%) and in the presence of late-onset pneumonia (12.5% vs. 40.7%). When the pathogen remained unknown, half of the patients died and de-escalation was not performed.

CONCLUSION

De-escalation was the most important cause of antibiotic modification, being more feasible in early-onset pneumonia and less frequent in the presence of nonfermenting Gram-negative bacillus. The impact of quantitative tracheal aspirates or bronchoscopic techniques was comparable in terms of mortality.

Utility of blood cultures in the management of adults with community acquired pneumonia discharged from the emergency department

STUDY OBJECTIVE

To assess the clinical value of blood cultures (BCs) in the management of adult patients discharged from the emergency department (ED) with a diagnosis of community acquired pneumonia (CAP).

METHODS

The courses of antibiotic regimens and outcomes of patients with positive BC results were examined to assess their influence on BCs.

RESULTS

BCs were obtained from 289 outpatients. Six clinically significant organisms were identified (a yield of 2.1%). Outpatients with CAP who had blood cultures performed had a 0.69% (2 of 289) chance of having a change of treatment directed by the results of the culture.

CONCLUSION

BCs have little utility in the ambulatory management of CAP.

Azithromycin for acute lower respiratory tract infections

BACKGROUND

The spectrum of acute lower respiratory tract infection ranges from acute bronchitis and acute exacerbations of chronic bronchitis to pneumonia. Annually approximately five million people die of acute respiratory tract infections. Among these, pneumonia represents the most frequent cause of mortality, hospitalization and medical consultation. Azithromycin is a new macrolide antibiotic, structurally modified from erythromycin and is noted for its activity against some gram-negative organisms associated with respiratory tract infections, particularly Haemophilus influenzae (H. influenzae).

OBJECTIVES

To compare the effectiveness of azithromycin to amoxycillin or amoxycillin/clavulanic acid (amoxyclav) in the treatment of LRTI, in terms of clinical failure, incidence of adverse events and microbial eradication.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2003), MEDLINE (January 1966 to January Week 3, 2004), and EMBASE (January 1988 to 2003).

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials, which compared azithromycin to amoxycillin or amoxycillin/clavulanic acid in patients with clinical evidence of acute LRTI: acute bronchitis, pneumonia, and acute exacerbation of chronic bronchitis were studied.

DATA COLLECTION AND ANALYSIS

The criteria for assessing study quality were generation of allocation sequence, concealment of treatment allocation, blinding, and completeness of the trial. All types of acute lower respiratory tract infections were initially pooled in the meta-analyses. Funnel plot was used to examine publication bias. The heterogeneity of results was investigated by the forest plot and Chi-square test. Index of I(2) was also used to measure inconsistency results among trials. Subgroup analysis was conducted for age, types of respiratory tract infection and types of antibiotic in control groups. Sensitivity analysis was conducted under the condition of trial size and concealment of treatment allocation.

MAIN RESULTS

Fourteen trials with 2,521 enrolled patients used 2,416 patients in the analysis. A total of 1,350 patients received azithromycin and 1,066 received amoxicillin or amoxicillin-clavulanic acid. The pooled analysis of all trials showed that there was no significant difference in the incidence of clinical failure on about day 10 to 14 after therapy started between the two groups (relative risk (RR) (random effects) 0.96; 95% CI 0.58 to 1.57). Sensitivity analysis showed that a reduction of clinical failure in azithromycin-treated patients (RR 0.52; 95% CI 0.24 to 1.12) in three adequately concealed studies, compared to RR 1.14 (95% CI 0.62 to 2.08) in eleven studies with inadequate concealment. Eleven trials reported the incidence of microbial eradication and there was no significant difference between the two groups (RR 0.98; 95% CI 0.91 to 1.07). The reduction of adverse events in azithromycin group was RR 0.75 (95% CI 0.56 to 1.00).

REVIEWERS' CONCLUSIONS

There is unclear evidence that azithromycin is superior to amoxicillin or amoxicillin-clavulanic acid in treating acute LRTI. Future trials with high methodological quality are needed.

Physician-perceived barriers to adopting a critical pathway for unity-acquired pneumonia

BACKGROUND

A proven efficacious and evidence-based critical pathway for community-acquired pneumonia (CAP) was implemented in six hospitals across a health service region (Edmonton, Canada). After one year (November 2000-November 2001), the pathway had reduced average length of stay by 1 day (from 10.8 to 9.8 days, p < .001). However, great variation was observed in physician adherence to the pathway.

METHODS

Physician-perceived barriers to adoption of the CAP pathway were identified through in-depth interviews. Data saturation was reached after 10 physicians, representing a convenience sample of those willing to participate, were interviewed.

RESULTS

Self-reported adherence to the CAP pathway was 75% (range 50%-100%). Qualitative analysis of the interview data indicated that comments could be grouped into five themes: (1) limited applicability, (2) lack of flexibility to accommodate atypical clinical presentations, (3) perception of insufficient evidence to support recommendations, (4) local organizational barriers, and (5) need for local adaptation. For example, one physician remarked that his community hospital had insufficient staff to support collection of lab samples for all patients.

DISCUSSION

Interventions to increase pathway adoption and further improve quality of CAP care should address the identified barriers. For example, local audit and feedback of outcomes data to persuade physicians of the benefits of CAP pathways will need to be instituted.

Cefepime versus ceftazidime for treatment of pneumonia

Consecutive patients with pneumonia, treated with cefepime (n = 66) or ceftazidime (n = 132), were evaluated in a retrospective, observational study. There was no significant difference between the two treatment groups with respect to age, underlying diseases, acute physical and chronic health evaluation score, intensive care unit admission, presence of sepsis, community or hospital acquisition, causative organism, duration of therapy, death, cure or improvement in infection, adverse events, superinfections, presence of vancomycin-resistant enterococcus (VRE) and resistance to therapy. Post-therapy hospitalization (days) and vancomycin co-administration were significantly lower, and time to vancomycin initiation significantly higher, in the cefepime compared with the ceftazidime group. The results suggest a trend towards less resistance on therapy, less VRE, reduced vancomycin use and shorter post-therapy hospitalization in patients treated with cefepime compared with ceftazidime. The clinical outcomes for hospitalized patients treated for serious pneumonia were similar between the two groups.

Predicting Bacteremia in Patients with Community-Acquired Pneumonia

It is recommended that blood cultures be performed on all patients admitted to the hospital with pneumonia. Questions regarding the cost-effectiveness of this practice have emerged. We used data on 13,043 Medicare patients hospitalized with pneumonia to determine predictors of bacteremia. Predictors included recent antibiotic treatment, liver disease, and three vital-sign and three laboratory abnormalities. Patients were stratified into three groups on the basis of the likelihood of bacteremia. We then created a decision support tool that recommends performing no blood cultures on patients with low likelihood of bacteremia, one blood culture on patients with moderate likelihood of bacteremia, and two blood cultures on patients with higher likelihood of bacteremia. This tool was then applied to a validation cohort of 12,771 patients with pneumonia. Use of the decision support tool would result in 38% fewer blood cultures being performed when compared with the standard practice of performing two blood cultures for each patient and identified 88 to 89% of patients with bacteremia. A simplified tool performed similarly overall but was less sensitive than was the first tool among pneumonia severity index Class V patients. These tools may allow clinicians to target patients with pneumonia in whom blood cultures are most likely to yield a pathogen.

Blood cultures in ambulatory patients who are discharged from emergency with community-acquired pneumonia

OBJECTIVES

To determine the factors that predict whether or not ambulatory patients with community-acquired pneumonia (CAP) treated in an emergency room (ER) setting will have blood cultures drawn and the factors that predict a positive blood culture.

METHODS

Prospective observational study of all patients with a diagnosis of CAP, as made by an ER physician, who presented to any of seven Edmonton-area ERs over a two-year period.

RESULTS

Seven hundred ninety-three (19.2%) of 4124 patients with CAP had blood cultures drawn. The site-specific blood culture rates ranged from 7.8% to 25% (P<0.001); 41 of 793 (5.1%) were positive. Streptococcus pneumoniae accounted for 58.5% of the isolates while Staphylococcus aureus and Escherichia coli each accounted for 14.6%, or six patients each. Only two of the 24 patients with S pneumoniae bacteremia were subsequently admitted to hospital while all six of the patients with S aureus were admitted. Only one of the six patients with E coli bacteremia was treated at home. No factors were predictive of positive blood cultures on multivariate analysis.

CONCLUSIONS

Physicians are selective in ordering blood cultures on patients with ambulatory pneumonia who present to an ER, and the positivity rate of 5.1% is quite high. No factors are predictive of positive blood cultures on multivariate analysis, thus clinical judgment has to prevail in the decision to perform blood cultures. Breakthrough bacteremia can occur with microorganisms susceptible to the antibiotics that the patient is receiving.

Connective tissue responses in acute community-acquired pneumonia

Circulating connective tissue components including the aminoterminal propeptides of type III collagen (PIIINP), type I collagen (PINP) and hyaluronan were determined in patients hospitalised for pneumonia of suspected bacterial origin. Ninety patients were included, 64 of these were followed prospectively for up to 21 days after initiation of therapy. Serum PIIINP was determined by RIA, s-PINP by ELISA, and s-hyaluronan by a radiometric assay. S-PIIINP rose significantly above the zero value within 24 h in both pneumococcal pneumonia (T0: 5.3 microg/l, 95% CI: 2.7-8.1 microg/l vs. T1: 6.7 microg/l, 95% CI: 3.8-9.1, P<0.01) and in pneumonia of unknown aetiology (T0: 4.0 microg/l, 95% CI: 3.6-4.8 vs. T1: 4.5 microg/l, 95% CI: 3.8-5.1, P<0.05) followed by a gradual decline. At T1, S-PIIINP was higher in pneumococcal pneumonia compared with pneumonia of unknown aetiology (P<0.05). By contrast, s-PINP tended to decline within 24 h in both pneumococcal pneumonia (T1: 30 microg/l, 95% CI: 23-40, ns) and in pneumonia of unknown aetiology (T1: 32 microg/l, 95% CI: 22-42, ns) followed by a steady increase. The PINP antigen size distribution remained constant throughout the follow-up period. S-hyaluronan in pneumococcal pneumonia paralleled s-PIIINP reaching a peak value on day 1 (121 microg/l, 95% CI: 65-191, P=0.38). There was a positive correlation between s-PIIINP and C-reactive protein (CRP). The study demonstrates, that community-acquired pneumonia elicits a differentiated mesenchymal response, which is turned down in response to successful antibiotic therapy.

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

STUDY OBJECTIVE

To assess the clinical usefulness of blood cultures (BCs) in the management of patients hospitalized with community-acquired pneumonia (CAP).

DESIGN

A prospective, observational study to investigate the contribution of BCs to the management and outcomes of adult patients presenting with CAP.

SETTING

Nineteen Canadian hospitals.

PATIENTS

Adults admitted to the hospital with CAP between January 1, 1998, and July 31, 1998.

INTERVENTIONS

The courses of therapy in patients for whom BC results yielded organisms considered to be clinically significant were analyzed to determine whether the BCs had contributed to management or outcome.

MEASUREMENTS AND RESULTS

Forty-three of 760 patients had significantly positive BC results. Patients with CAP who had BCs performed had a 1.97% chance (15 of 760 patients) of having a change of therapy directed by BC results. Patients in whom BCs yielded positive results had a 34.8% chance (15 of 43 patients) of having a change in therapy determined by BC results, and had a 58.1% chance (25 of 43 patients) of having a course of therapy contraindicated by BC results. Severity of illness, as measured by the pneumonia severity index, correlated poorly with the yield of BCs. BC results were positive in 8.0% of patients in risk classes I and II, 6.2% of patients in risk class III, 4.6% of patients in risk class IV, and 5.2% of patients in risk class V.

CONCLUSION

BCs have limited usefulness in the routine management of patients admitted to the hospital with uncomplicated CAP.

Microbiological testing and outcome of patients with severe community-acquired pneumonia

STUDY OBJECTIVES

The study documents the impact of microbiological investigations on therapeutic decisions and outcome in patients with severe community-acquired pneumonia (SCAP).

DESIGN

Retrospective analysis of prospectively collected data.

SETTING

ICUs in two teaching Spanish hospitals.

PATIENTS

Two hundred four consecutive patients admitted to intensive care with SCAP.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

One hundred six patients required intubation, while 98 other patients did not (81 of these patients were managed with noninvasive mechanical ventilation). The microbiologic diagnosis was established in 57.3% of patients. The most common pathogens were Streptococcus pneumoniae, Legionella pneumophila, and Haemophilus influenzae. Pseudomonas (6.6.% vs 1.0%, p < 0.05) and Legionella (15.1% vs 7.1%, p < 0.05) were more frequently documented in intubated patients. Overall mortality was 23.5% (44.3% in intubated patients), with S pneumoniae (n = 7), Pseudomonas aeruginosa (n = 7), and L pneumophila (n = 5) being the most common lethal pathogens. Bacteriological investigation led to changes in antibiotic prescription in 41.6% of patients, including 11 patients (5%) in whom initial treatment was ineffective against the microbial isolates. The most frequent reason for changes was simplification of therapy in 65 episodes (31.8%).

CONCLUSIONS

We conclude that microbiological testing is fully justified in patients with SCAP, because identifying the causative agent and adjusting treatment both impact on patient outcome. Our findings suggest that intubated patients should be empirically treated for Pseudomonas and Legionella while awaiting bacteriology results.

Applying sputum as a diagnostic tool in pneumonia: limited yield, minimal impact on treatment decisions

STUDY OBJECTIVES

We evaluated the role of sputum examination in the management of patients with community-acquired pneumonia (CAP) in a primary-care hospital without microbiologic laboratory facilities.

DESIGN AND INTERVENTIONS

A diagnostic strategy using regular collection of sputum samples, Gram staining in a local laboratory, and mailing of samples to a commercial laboratory for culture analysis.

SETTING

A 200-bed primary-care hospital without subspeciality physicians.

PATIENTS

One hundred sixteen consecutive patients with a diagnosis of CAP were prospectively evaluated during a 12-month period.

RESULTS

Of 116 patients, 42 patients (36%) were capable of producing a sputum sample. Age > or = 75 years (odds ratio [OR], 0.4; 95% confidence interval [CI], 0.18 to 0.93) and prior ambulatory antimicrobial treatment (OR, 3.2; 95% CI, 1.2 to 8.4) were independent predictors of sputum production. A delay in collection and processing of sputum samples of > 24 h was present in 31% and 39%, respectively. A delay in collection yielded an increased number of Gram-negative enteric bacilli and nonfermenters (44% vs. 7%, p = 0.056). A delay in processing was associated with an increased number of Candida spp isolates (33% vs. 9%, p = 0.16). The overall diagnostic yield was low (10 of 116 patients, 9%) due to a limited number of valid samples (n = 23 of 42 patients, 55%) and a limited number of definitely or probably positive samples on Gram's stain and culture (n = 10 of 42 patients, 24%). Prior ambulatory antimicrobial treatment was associated with a reduction in diagnostic yield (14% vs. 56%, p = 0.09). The impact of diagnostic results on antimicrobial treatment decisions was minimal, with antimicrobial treatment directed to diagnostic results in only one patient.

CONCLUSIONS

We conclude that in this setting representative of primary-care hospitals in Germany, sputum had a low diagnostic yield and did not contribute significantly to patient management.

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.

Estudo de casos hospitalizados por pneumonia comunitária no período de um ano

Introdução: Apesar dos avanços obtidos nos métodos propedêuticos, cerca de 50% dos casos de pneumonia adquirida na comunidade não têm sua etiologia esclarecida, inclusive os hospitalizados. Apesar disso, a terapêutica adequada proporciona baixas taxas de mortalidade na maioria dos casos. Objetivos: Descrever a epidemiologia, formas de apresentação, o rendimento dos testes diagnósticos, a permanência hospitalar, a morbidade e mortalidade de 42 pacientes consecutivos, internados para tratamento de PAC. Métodos: Foram incluídos pacientes com quadro clínico compatível com PAC, opacidade radiológica pulmonar recente e com dois itens entre febre, tosse produtiva e leucocitose. A solicitação de exames complementares obedeceu à necessidade de cada caso. Resultados: Dos 42 pacientes, com idade de 64,7 ± 16,8 anos, 27 (64,3%) masculinos, 27 (64%) apresentavam co-morbidades. Dezessete (40,5%) estavam em uso de antibióticos à admissão. Pneumonia grave ocorreu em oito casos (19%); não houve diferença quanto à gravidade (p = 0,57) e permanência hospitalar (p = 0,25) entre os grupos > de 60 ou <= de 60 anos. A permanência hospitalar média foi de 14,3 ± 7,6 dias. Diagnóstico etiológico definitivo foi obtido em três casos: Legionella sp em dois, S. aureus em um caso. Em 31 (74%), manteve-se o antibiótico inicial; em 11 (26%) houve troca, seis (54,5%) devido à má resposta clínica e cinco (45,5%) devido ao resultado microbiológico. Hemoculturas foram feitas em 16 casos (38%), positivas em apenas um (6,3%). Nove amostras de escarro (9/22, 41%) foram validadas. Ocorreu um óbito (2,4%), por pneumonia grave, em um paciente com neoplasia. Conclusões: O diagnóstico etiológico em PAC, mesmo em internados, é obtido em uma minoria de casos, contribuindo para isso o uso concorrente de antibióticos. A terapêutica empírica adequada proporciona baixas taxas de mortalidade. Os testes diagnósticos devem ser empregados de maneira individualizada.

An observational study on the epidemiology of respiratory tract bacterial pathogens and their susceptibility to four injectable beta-lactam antibiotics: piperacillin, piperacillin/tazobactam, ceftazidime and ceftriaxone

Bacterial infections of the respiratory tract account for a large proportion of total medical consultations in general practice. In recent years, antibiotic resistance has increased alarmingly in a number of bacterial species that are common causes of these infections. The aim of this observational study was to determine the antibiotic resistance of microbial agents isolated from patients with acute or acutely exacerbated respiratory infections. Subjects recruited as potential sources of bacteria were either outpatients seen in a number of specialized clinics and hospital practices, or hospitalized patients. Overall, 648 consecutive patients (67% male, mean age 48.1+/-27.0 years) with infection of the upper or lower respiratory tract were observed during a 13-month period. A total of 551 pathogenic microbial strains were isolated and tested for their in vitro susceptibility to piperacillin, piperacillin/tazobactam, ceftazidime, and ceftriaxone. Among all isolates, the four most frequent pathogens were Pseudomonas aeruginosa (132 isolates, 24%), Streptococcus pyogenes (99 isolates, 18%), Staphylococcus aureus (93 isolates, 17%), and Klebsiella pneumoniae (46 isolates, 8%). The susceptibility of gram-positive isolates ranged from 97.5% to 95.1%, and no remarkable difference was found in the antibacterial activity of tested b-lactam antibiotics. The susceptibility of gram-negative isolates to piperacillin and piperacillin/tazobactam was also similar: 96.5% and 97.1%, respectively. In contrast, differences were found between piperacillin (or piperacillin/tazobactam) and either ceftazidime (p=0.003) or ceftriaxone (p<0.0003) in gram-negative isolates. We conclude that, despite the extensive use of beta-lactam antibiotics (piperacillin, ceftazidime, and ceftriaxone) in medical practice during the past three decades, the susceptibility of the most common pathogens involved in the etiology of upper and lower respiratory tract infections to these antibiotics is still high. In particular, bacterial resistance developed by gram-positive organisms against piperacillin is negligible and not alarming.

Clinical policy for the management and risk stratification of community-acquired pneumonia in adults in the emergency department

This clinical policy represents an approach that emphasizes key clinical information to determine the severity of CAP. By using this approach, a determination of whether the patient can be treated as an outpatient or inpatient may be made. Recommendations about the utility of ancillary studies and the use of antibiotics are also given. As more of the questions are answered through controlled studies, an evidence-based approach to this problem will become increasingly important in improving the outcome of patients with CAP.

The influence of the severity of community-acquired pneumonia on the usefulness of blood cultures

The value of blood cultures in community-acquired pneumonia (CAP) has been questioned. At issue is the potential for blood cultures to change management. We prospectively studied the yield and impact of blood cultures in patients admitted with CAP. Two hundred and nine subjects had at least two blood cultures prior to receiving antibiotics. The severity of CAP was graded using the Pneumonia Severity Index (PSI). Twenty-nine patients (13.9%) had a pathogen identified by blood culture. The yield of blood cultures increased with PSI grade (I--5.3%, II--10.2%, III--10.3%, IV--16.1%, V--26.7%), as did the likelihood of blood cultures changing antibiotic therapy (I to III--0%, IV--9.7%, V--20.0%). One hundred and seventy-nine (85.6%) patients received a quinolone, limiting the impact of pathogens resistant to beta-lactams. Four of 16 patients (25.0%) with a culture (blood or sputum)-guided change in antibiotic therapy died, compared to five of 31 patients (16.1%) who had an empiric change. Blood cultures are of minimal value in mild to moderate CAP, and should be limited to patients with PSI grade IV or V CAP unless a specific risk factor for pathogens resistant to the empiric therapy is present.

Nonvalue of the initial microbiological studies in the management of nonsevere community-acquired pneumonia

STUDY OBJECTIVE

To assess the value of the initial microbiological studies (MBS), consisting of sputum Gram's stains, sputum cultures, and blood cultures, in the etiologic diagnosis of community-acquired pneumonia (CAP) without comorbidity.

DESIGN

A prospective study of 74 adult patients hospitalized with nonsevere CAP empirically treated according to the American Thoracic Society guidelines (ATS-GL) and evaluated with Gram's stains and cultures of valid sputum specimens and blood cultures.

SETTING

University-affiliated community hospital.

RESULTS

Gram's stain of a valid sputum specimen failed to identify the etiologic agent in all patients. Sputum cultures identified pathogens in only four patients (5%). The results of all blood cultures were negative. All patients responded to the initial empiric antibiotic coverage selected according to the ATS-GL, and the results of the initial MBS had no clinical impact.

CONCLUSION

The initial MBS, such as sputum Gram's stains, sputum cultures, and blood cultures, have no value in the management of nonsevere CAP without comorbid factors.

A national confidential enquiry into community acquired pneumonia deaths in young adults in England and Wales. British Thoracic Society Research Committee and Public Health Laboratory Service

BACKGROUND

The aim of this study was to describe the frequency, causal pathogens, management, and outcome of a population of young adults who died from community acquired pneumonia (CAP).

METHODS

Pneumonia deaths in England and Wales in adults aged 15-44 were identified between September 1995 and August 1996. Patients with underlying chronic illness including HIV infection were excluded. Clinical details for each case were collected from the hospital and general practitioner records.

RESULTS

Death from CAP was identified in 27 previously well young adults (1.2 per million population per year). Twenty were known to have consulted a GP for this illness. Nine received antibiotics before hospital admission. A causative pathogen was identified in 17 cases (Streptococcus pneumoniae in eight). Bacteraemia was present in seven. All patients who reached a hospital ward received antibiotics (69% within two hours of admission). The British Thoracic Society antibiotic guidelines for severe CAP were followed in only 10 cases. Cardiac arrest at home or on arrival at hospital occurred in six cases, one of whom was successfully resuscitated. Of the remaining 21 patients, 71% had two or more markers of severe CAP. All 22 who were admitted reached an intensive care unit, but 11 of these required transfer to another hospital for some aspect of intensive care. One third of patients died within 24 hours of presenting to the hospital.

CONCLUSIONS

Death from CAP in previously fit young adults still occurs. While some deaths might be preventable by better patient management, most are unlikely to be preventable by current management practices.

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.