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

A score to predict Pseudomonas aeruginosa infection in older patients with community-acquired pneumonia

BACKGROUND

In Thailand, the incidence of community-acquired pseudomonal pneumonia among 60- to 65-year-olds ranges from 10.90% to 15.51%, with a mortality rate of up to 19.00%. Antipseudomonal agents should be selected as an empirical treatment for elderly patients at high risk for developing this infection. The purpose of this study was to identify risk factors and develop a risk predictor for Pseudomonas aeruginosa infection in older adults with community-acquired pneumonia (CAP).

METHODS

A retrospective data collection from an electronic database involved the elderly hospitalized patients with P. aeruginosa- and non-P. aeruginosa-causing CAP, admitted between January 1, 2016, and June 30, 2021. Risk factors for P. aeruginosa infection were analysed using logistic regression, and the instrument was developed by scoring each risk factor based on the beta coefficient and evaluating discrimination and calibration using the area under the receiver operating characteristic curve (AuROC) and observed versus predicted probability (E/O) ratio.

RESULTS

The inclusion criteria were met by 81 and 104 elderly patients diagnosed with CAP caused by P. aeruginosa and non-P. aeruginosa, respectively. Nasogastric (NG) tube feeding (odd ratios; OR = 40.68), bronchiectasis (B) (OR = 4.13), immunocompromised condition (I) (OR = 3.76), and other chronic respiratory illnesses (r) such as atelectasis, pulmonary fibrosis, and lung bleb (OR = 2.61) were the specific risk factors for infection with P. aeruginosa. The "60-B-r-I-NG" risk score was named after the 4 abbreviated risk variables and found to have good predicative capability (AuROC = 0.77) and accuracy comparable to or near true P. aeruginosa infection (E/O = 1). People who scored at least two should receive empirically antipseudomonal medication.

CONCLUSIONS

NG tube feeding before admission, bronchiectasis, immunocompromisation, atelectasis, pulmonary fibrosis and lung bleb were risk factors for pseudomonal CAP in the elderly. The 60-B-r-I-NG was developed for predicting P. aeruginosa infection with a high degree of accuracy, equal to or comparable to the existing P. aeruginosa infection. Antipseudomonal agents may be started in patients who are at least 60 years old and have a score of at least 2 in order to lower mortality and promote the appropriate use of these medications.

Characteristics and local risk factors of community-acquired and health-care-associated Staphylococcus aureus pneumonia

This study aims at identifying characteristics, risk factors and mortality of community-acquired (CAP) and health-care-associated pneumonia (HCAP) by Staphylococcus aureus (S. aureus). We retrieved adults with S. aureus CAP or HCAP diagnosed by blood or pleural effusion culture in 2.6 years, and compared with those of Streptococcus pneumoniae (S. pneumoniae) CAP or HCAP diagnosed by blood or respiratory culture, or urine antigen. We found 18 patients with CAP and 9 HCAP due to S. aureus (female 33%, 66.6 ± 12.4 years-old), and 48 patients with CAP and 15 HCAP due to S pneumoniae (female 41%, 69.5 ± 17.5 years). Diabetes mellitus (52% vs. 24%, p = 0.019), hemodialysis (11% vs. 0%, p = 0.046), skin lesions (44% vs. 0%, p < 0.001), cavitary nodules (37% vs. 1.6%, p < 0.001) and pleural effusions (48% vs. 18%, p = 0.007) were more common in staphylococcal than pneumococcal group. Three patients with staphylococcal pneumonia had acute myocardial infarction. Pneumonia severity index (139 ± 52 vs. 109 ± 43, p = 0.005) and 30-day mortality (41% vs. 9.5%, p = 0.001) were higher in staphylococcal group. Multivariate analysis showed underlying disease (especially cancer and cirrhosis), risk class 4/5, altered mentality, shock and bilateral pneumonia were risk factors for 30-day mortality.

Severe community-acquired pneumonia in general medical wards: outcomes and impact of initial antibiotic selection

Background

Most international guidelines recommend empirical therapy for community-acquired pneumonia (CAP) to be based on site of care. Some patients with severe CAP are managed in general wards because of limited intensive care unit (ICU) bed or because of unrecognition of the pneumonia severity. Appropriate initial antibiotic treatment for severe CAP outside ICU has not yet been established. This study aimed to determine the prevalence and the impact of initial antibiotic selection on the outcomes of patients with severe CAP who were admitted and managing in general wards.

Methods

This prospective observational study included consecutive patients hospitalized for presumed CAP in general wards over a 1-year period. Severe CAP was identified using the 2007 Infectious Diseases Society of America (IDSA)/American Thoracic Society (ATS) criteria. Initial antibiotic treatment in the first 24 h were collected. The primary outcome was the rate of unfavorable outcome (composite outcome of treatment failure and in-hospital death). The secondary outcome was the number of hospital-free days assessed 30 days after enrollment into the study.

Results

There were 94 patients hospitalized with CAP of which 50 (53.2%) patients were compatible with severe CAP. An etiologic diagnosis was found in 43 (45.8%) patients. The most common pathogens identified in patients with severe CAP were Staphylococcus aureus (28.6%) and Klebsiella pneumoniae (28.6%), followed by Pseudomonas aeruginosa (17.9%). Patients with severe CAP had significantly more positive blood culture than patients with non-severe CAP (24% VS 4.5%; p = .008). Initial antibiotic treatment were discordant with the IDSA/ATS guidelines in 42% of all patients hospitalized with CAP, and 52% of patients with severe CAP. Multivariate analysis revealed that age (OR 1.1, 95% CI 1.01–1.1) and initial antibiotic treatment discordant to guidelines for severe CAP in ICU (OR 4.6, 95% CI 1.3–17.1) were independent risk factors of the unfavorable outcome of patients with severe CAP. Patients with unfavorable outcome had lower number of hospital-free days than patients with favorable outcome (5.2 ± 8 days VS 18 ± 7.1 days; p < .001).

Conclusions

Patients with severe CAP outside ICU should be recognized for appropriate initial antibiotic selection to improve outcomes.

Cough

Pharmacists play an important role in the assessment and management of patients with cough. By obtaining a focused clinical history from the patient, they can identify patients who need to be referred to their physician or to the emergency room, as well as which patients can be managed at home. Red flags that prompt referral include severe systemic illness, respiratory distress, hemoptysis, and altered level of consciousness. Patients with underlying chronic illnesses such as chronic obstructive pulmonary disease, asthma, and heart failure who present with cough should be assessed for possible exacerbation of their illness and should be referred if this is suspected. Determining the duration of cough is an important step, as this helps identify possible etiologies. Cough <3-week duration is categorized as acute, 3- to 8-week duration is subacute, and > 8-week duration is a chronic cough. Patients with cough lasting >3 weeks should generally be referred for further evaluation and management. Acute cough is often infectious but can also be due to exacerbation of underlying illness or could be medication-related. Upper airway cough syndrome (UACS) is one of the most common causes of subacute and chronic cough. Several different etiologies lead to UACS, which is thought to be caused by postnasal drip ± sensitization of cough receptors in the respiratory tract. First-generation antihistamines or decongestants are therapeutic options when UACS is suspected. It is important to note that antitussive medications such as dextromethorphan can actually prolong illness in patients with a productive cough and are thus not recommended. Monitoring parameters and frequency of follow-up depend on underlying cause, severity of illnesses, past medical history, as well as medication changes.

Moving Past the Routine Use of Macrolides-Reviewing the Role of Combination Therapy in Community-Acquired Pneumonia

PURPOSE OF REVIEW

Despite advances in diagnostic microbiology and sepsis management, community-acquired pneumonia (CAP) remains a significant cause of morbidity and mortality. Current recommendations regarding the use of beta-lactams in combination with macrolides published in clinical practice guidelines are variable and based on low-quality evidence that is frequently retrospective, observational, and heterogeneous in nature. While population-based studies have historically suggested improved clinical outcomes with the routine use of macrolide combination therapy in hospitalized patients with CAP, emerging evidence from recent randomized controlled trials has challenged this practice. In this article, we discuss the historical rationale and current evidence for combination macrolide therapy in the management of CAP.

RECENT FINDINGS

Recent randomized controlled trials have assessed the non-inferiority of beta-lactam monotherapy compared to beta-lactam/macrolide combination therapy in adult patients hospitalized with CAP. Beta-lactam monotherapy was associated with equivalent clinical outcomes in patients with mild to moderate CAP. Patients with severe CAP managed with beta-lactam monotherapy have demonstrated worse clinical outcomes when compared to patients treated with combination therapy. In addition, previous beta-lactam exposure prior to hospitalization has not been shown to negatively impact outcomes in patients managed with beta-lactam monotherapy in the hospital. Current evidence supports the use of beta-lactam monotherapy in adult patients hospitalized with mild to moderate CAP. While existing evidence supports the use of combination therapy in patients with severe pneumonia, further large-scale randomized controlled trials are urgently needed to clarify the role of combination therapy in this population.

[Short-course antibiotic regimens: Up-to-date]

Antibiotic treatment durations are not well documented. Yet, dramatic emergence of multi-drug resistant organisms should lead to tend to decrease antibiotic selection pressure. Furthermore, it could lower health costs and reduce associated adverse events. Unfortunately, only few studies with rigorous methodology have been performed. We present the available data on frequent infections such as urinary tract infections, community acquired pneumonia, bone and joint infections and intra-abdominal infections. We underline the difficulties to perform such trials and discuss original options to a better evaluation of treatment duration.

A liquid chromatography-mass spectrometric method for the quantification of azithromycin in human plasma

A liquid chromatographic mass spectrometric assay for the quantification of azithromycin in human plasma was developed. Azithromycin and imipramine (as internal standard, IS) were extracted from 0.5 mL human plasma using extraction with diethyl ether under alkaline conditions. Chromatographic separation of drug and IS was performed using a C18 column at room temperature. A mobile phase consisting of methanol, water, ammonium hydroxide and ammonium acetate was pumped at 0.2 mL/min. The mass spectrometer was operated in positive ion mode and selected ion recording acquisition mode. The ions utilized for quantification of azithromycin and IS were m/z 749.6 (M + H)(+) and m/z 591.4 (fragment) for azithromycin, and 281.1 m/z for internal standard; retention times were 6.9 and 3.4 min, respectively. The calibration curves were linear (r(2) > 0.999) in the concentration ranges of 10-1000 ng/mL. The mean absolute recoveries for 50 and 500 ng/mL azithromycin and 1 µg/ mL IS were >75%. The percentage coefficient of variation and mean error were <11%. Based on validation data, the lower limit of quantification was 10 ng/mL. The present method was successfully applied to determine azithromycin pharmacokinetic parameters in two obese volunteers. The assay had applicability for use in pharmacokinetic studies.

Switch therapy in hospitalized patients with community-acquired pneumonia: tigecycline vs. levofloxacin

Background

Switch therapy is a management approach combining early discontinuation of intravenous (IV) antibiotics, switch to oral antibiotics, and early hospital discharge. This analysis compares switch therapy using tigecycline versus levofloxacin in hospitalized patients with community-acquired pneumonia (CAP).

Methods

A prospective, randomized, double-blind, Phase 3 clinical trial; patients were randomized to IV tigecycline (100 mg, then 50 mg q12h) or IV levofloxacin (500 mg q24h). Objective criteria were used to define time to switch therapy; patients were switched to oral levofloxacin after ≥6 IV doses if criteria met. Switch therapy outcomes were assessed within the clinically evaluable (CE) population.

Results

In the CE population, 138 patients were treated with IV tigecycline and 156 were treated with IV levofloxacin. The proportion of the population that met switch therapy criteria was 67.4% (93/138) for tigecycline and 66.7% (104/156) for levofloxacin. The proportion that actually switched to oral therapy was 89.9% (124/138) for tigecycline and 87.8% (137/156) for levofloxacin. Median time to actual switch therapy was 5.0 days each for tigecycline and levofloxacin. Clinical cure rates for patients who switched were 96.8% for tigecycline and 95.6% for levofloxacin. Corresponding cure rates for those that met switch criteria were 95.7% for tigecycline and 92.3% for levofloxacin.

Conclusions

Switch therapy outcomes in hospitalized patients with CAP receiving initial IV therapy with tigecycline are comparable to those of patients receiving initial IV therapy with levofloxacin. These data support the use of IV tigecycline in hospitalized patients with CAP when the switch therapy approach is considered.

ClinicalTrials.gov Identifier

NCT00081575

Macrolides vs. quinolones for community-acquired pneumonia: meta-analysis of randomized controlled trials

The relative efficacy, safety and ecological implications of macrolides vs. quinolones in the treatment of community-acquired pneumonia (CAP) are debatable. We performed a systematic review and meta-analysis of randomized controlled trials comparing any macrolide vs. any quinolone for the treatment of CAP among adult inpatients or outpatients, as monotherapy or both in combination with a beta-lactam. We did not limit inclusion by pneumonia severity, publication status, language or date of publication. The primary outcomes assessed were 30-day all-cause mortality and treatment failure. Two authors independently extracted the data. Fixed effect meta-analysis of risk ratios (RRs) with 95% confidence intervals was performed. Sixteen trials (4989 patients) fulfilling inclusion criteria were identified, mostly assessing outpatients with mild to moderate CAP. All-cause mortality was not significantly different for macrolides vs. quinolones, RR 1.03 (0.63-1.68, seven trials), with a low event rate (2%). Treatment failure was significantly lower with quinolones, RR 0.78 (0.67-0.91, 16 trials). The definition of failure used in the primary studies was not clearly representative of patients' benefit. Microbiological failure was lower with quinolones, RR 0.63 (0.49-0.81, 13 trials). All adverse events, adverse events requiring discontinuation and any premature antibiotic discontinuation were significantly more frequent with macrolides, mainly on account of gastrointestinal adverse events. Resistance development was not assessed in the trials. Randomized controlled trials show an advantage of quinolones in the treatment of CAP with regard to clinical cure without need for antibiotic modification at end of treatment and gastrointestinal adverse events. The clinical significance of this advantage is unclear.

Prescription of antibiotics for adults hospitalized with community-acquired pneumonia in Korea in 2004: a population-based descriptive study

BACKGROUND AND OBJECTIVE

Community-acquired pneumonia (CAP) is generally considered to be a major cause of morbidity and mortality. There is much controversy regarding the optimal choice of antibiotics for patients with CAP. The aim of this study was to identify the antibiotics prescribed for adults hospitalized with CAP in Korea during a calendar year.

METHODS

This population-based, descriptive epidemiological study was performed using data from nationwide health insurance claims from 1 January 2004 to 31 December 2004. The study population was adults (≥18 years old), who had been hospitalized with CAP as determined by discharge diagnosis, and who had been treated with antibiotics for ≥3 days. The exclusion criteria were tuberculosis, underlying malignancies and potential nosocomial pneumonia, based on the department providing care, or surgery reports during the admission.

RESULTS

Of the 5592 adults hospitalized with CAP, data for 3662 (65.5%) patients was eligible for inclusion in the analysis. This included data for 1899 (51.9%) males, and 2045 (55.8%) patients ≥65 years of age. The most frequently prescribed antimicrobial regimen was β-lactam/β-lactamase inhibitors and fluoroquinolones in combination (31.0%), followed by β-lactam/β-lactamase inhibitors plus macrolides (30.2%), monotherapy (17.0%), β-lactam/β-lactamase inhibitors plus aminoglycosides (12.9%), β-lactam/β-lactamase inhibitors plus clindamycin (4.9%), and cephalosporins plus fluoroquinolones (2.5%). Monotherapy included, in decreasing order of use, cephalosporins (6.0%), fluoroquinolones (3.5%), β-lactam/β-lactamase inhibitors (2.3%) and macrolides (2.2%).

CONCLUSIONS

In this study, patterns of antimicrobial prescription for patients hospitalized with CAP were assessed for the first time in Korea. There was divergence from the 2009 Korean guidelines for the treatment of CAP, reinforcing the need for assessment of physicians' adherence to the guidelines.

Evaluation of the World Health Organization criteria for chest radiographs for pneumonia diagnosis in children

Our objective was to compare the inter-observer level of agreement in diagnosing pneumonia using the World Health Organization (WHO) guidelines for the interpretation of radiographs. We conducted a prospective study in a pediatric emergency room. Fifteen observers (13 pediatricians, 2 radiologists) interpreted 200 pediatric (<5 years old) chest radiographs using the WHO guidelines. Observers were blinded to the clinical presentation. RESULTS were analyzed for kappa values. Individual readings were compared to two "gold standard" teams: (1) radiologist and pediatrician and (2) two radiologists.

RESULTS

Alveolar pneumonia, non-alveolar pneumonia, and no pneumonia were found (by radiologists) in 12.8%, 2.7%, and 78.6% of readings, respectively. The mean kappa values for alveolar pneumonia, non-alveolar pneumonia, and no pneumonia of observers versus the team consisting of a radiologist and a pediatrician were 0.73, 0.23, and 0.61, respectively. For non-alveolar pneumonia, the mean kappa value was higher for the gold standard consisting of a radiologist and a pediatrician when compared to the two-radiologist team. Pediatricians overdiagnosed "non-alveolar pneumonia" compared with radiologists. In contrast, for the alveolar pneumonia and no-pneumonia diagnoses, no significant differences were found.

CONCLUSIONS

The WHO guidelines for interpretation of chest radiographs result in high level of agreement between readers for the definition of "alveolar pneumonia" and "no pneumonia" but poor agreement for non-alveolar pneumonia. The disagreement with regard to the latter was associated with overdiagnosis by pediatricians, which may lead to overtreatment. We believe that radiographic non-alveolar pneumonia should not be an endpoint for clinical trials and research, nor should it be implemented in clinical setting.

Defining severe pneumonia

Pneumonia is an important clinical and public health problem. Identification and prediction of severe pneumonia are significant concerns. Attempts to define severe pneumonia should recognize that different purposes are served by different definitions; no single definition meets all needs. At present, several prediction models have been proposed or validated. Biomarkers are not yet ready for routine use. The authors recommend careful consideration of the implications of any given definition of pneumonia severity. Outcome studies are needed to integrate human and health care system factors with the application of pneumonia severity definitions.

Defining and predicting severe community-acquired pneumonia

PURPOSE OF REVIEW

Community-acquired pneumonia is a significant clinical and public health problem. Defining and predicting severe pneumonia is difficult but important.

RECENT FINDINGS

Several new predictive models and more sophisticated approaches to describing pneumonia severity have been recently proposed, with subsequent validation in varied patient populations. Early data suggest that biomarkers may be useful in the future.

SUMMARY

Definitions of pneumonia severity depend on the relevant clinical or public health question. A health services reference definition seems most useful in most settings. The Infectious Disease Society of America/American Thoracic Society 2007 guidelines and SMART-COP are two recent promising methods for predicting severe pneumonia at the time of presentation. The traditional pneumonia severity index and Confusion Uremia Respiratory rate Blood pressure (CURB)-65 models are less useful. Accurate assessment of severity has important implications for triage, outcome, and defining populations for research applications. Novel biomarkers, while somewhat promising, do not yet have a validated role in pneumonia severity assessment.

Door-to-antibiotic time for pneumonia in a rural emergency department

Objective:

The Joint Commission on Accreditation of Healthcare Organizations recommends that patients admitted to hospital with pneumonia receive their first dose of antibiotics within 6 hours of presenting to the emergency department (ED). Previous research in the United States indicates that rural hospitals may be better at achieving this benchmark than urban centres. This particular quality indicator has not yet been evaluated in Canada. The purpose of this study was to determine whether the target door-to-antibiotic (DTA) time of 6 hours or less could be met in a rural ED.

Methods:

We conducted a retrospective chart review of patients admitted to hospital with a diagnosis of pneumonia. Descriptive data for each case was collected, including demographic and timeline information. We analyzed DTA time, antibiotic type, route of administration, hospital length of stay and disposition at discharge.

Results:

We reviewed a total of 320 charts from Apr. 1, 2003, to Mar. 31, 2008. The final sample consisted of 143 patients (50.3% women) whose median age was 79 years. The median DTA time was 151 minutes and 81.8% of patients received their first dose of antibiotics within 6 hours. Patients received antibiotics either orally (47.6%), intravenously (47.6%) or both (4.8%). Single-agent respiratory fluoroquinolones were used 71.4% of the time. Median length of hospital stay was 4 days; most patients were discharged home (79.7%), 11 died, 11 were transferred and 7 were discharged to a nursing home.

Conclusion:

A DTA time of 6 hours or less is achievable in a rural ED.

Evaluation of the performance of CURB-65 with increasing age

There has been concern about the performance of CURB-65 in older patients with community-acquired pneumonia (CAP) and that younger patients who subsequently die are initially misclassified as having non-severe CAP. The purpose of this study was to evaluate the effect of age on the performance of CURB-65. We analysed data prospectively, collected in two UK hospitals. Patients were stratified into four age cohorts. Mortality in each cohort was then stratified by CURB-65 score. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and area under the receiver operating curve (AUROC) were calculated. Four hundred and twenty-eight patients were included. Misclassification of patients who subsequently died as non-severe CAP patients (CURB-65 score of < or =2) increased with increasing age (from 3% in the <65-year cohort to 27% in those aged >85 years). There were no deaths (0/105) in those aged <65 years who had a CURB-65 score of 0 or 1. At the British Thoracic Society cut-off for severe CAP (CURB-65 score of > or =3), CURB-65 performed best in 16-64-year-olds (PPV 0.4, NPV 0.97). The AUROC was significantly higher for the <65-year cohort in comparison with older patients (0.93 vs. 0.7, p <0.05). Clinicians should interpret the CURB-65 score with care in older patients referred to hospital with CAP. In those aged <65 years, however, CURB-65 appears to be able to identify a cohort of patients (CURB-65 score of 0 or 1) with very low mortality.

Severity scores for community-acquired pneumonia

An assessment of the severity of illness of a patient is one of the most important components of their early management. It guides decisions regarding the most appropriate site of care and the selection of empiric antibiotic therapy. In recent years, prediction tools, known as severity scores, have been promoted to assist early assessments of the severity of illness for patients with community-acquired pneumonia. Several different severity scores now exist and these have been modified over time. Each tool has particular strengths and weaknesses. This article reviews the evolution of severity scores for patients with community-acquired pneumonia and compares their performance in different patient cohorts for different outcomes of interest, as described in the published literature to date. It also discusses how these tools could be evaluated more comprehensively so that their place in patient management can be better appreciated.