The etiology of community-acquired pneumonia in Australia: why penicillin plus doxycycline or a macrolide is the most appropriate therapy

Australasian respiratory and emergency physicians do not use the pneumonia severity index in community-acquired pneumonia

BACKGROUND AND OBJECTIVE

The value of community-acquired pneumonia (CAP) severity scoring tools is almost exclusively reliant upon regular and accurate application in clinical practice. Until recently, the Australasian Therapeutic Guidelines has recommended the use of the Pneumonia Severity Index (PSI) in spite of poor user-friendliness.

METHODS

Electronic and postal survey of respiratory and emergency medicine physician and specialist registrar members of the Royal Australasian College was undertaken to assess the use of the PSI and the accuracy of its application to hypothetical clinical CAP scenarios. The confusion, urea, respiratory rate, blood pressure, age 65 or older (CURB-65) score was also assessed as a simpler alternative.

RESULTS

Five hundred thirty-six (228 respiratory, 308 emergency) responses were received. Only 12% of respiratory and 35% of emergency physicians reported using the PSI always or frequently. The majority were unable to accurately approximate PSI scores, with significantly fewer respiratory than emergency physicians recording accurate severity classes (11.8% vs 21%, OR 0.50, 95% CI: 0.37-0.68, P < 0.0001). In contrast, significantly more respiratory physicians were able to accurately calculate the CURB-65 score (20.4% vs 15%, OR 1.45, 95% CI: 1.10-1.91, P = 0.006).

CONCLUSIONS

Australasian specialist physicians primarily responsible for the acute management of CAP report infrequent use of the PSI and are unable to accurately apply its use to hypothetical scenarios. Furthermore, respiratory and emergency physicians contrasted distinctly in their use and application of the two commonest severity scoring systems--the recent recommendation of two further alternative scoring tools by Australian guidelines may add to this confusion. A simple, coordinated approach to pneumonia severity assessment across specialties in Australasia is needed.

Etiological analysis and predictive diagnostic model building of community-acquired pneumonia in adult outpatients in Beijing, China

BACKGROUND

Etiological epidemiology and diagnosis are important issues in adult community-acquired pneumonia (CAP), and identifying pathogens based on patient clinical features is especially a challenge. CAP-associated main pathogens in adults include viruses as well as bacteria. However, large-scale epidemiological investigations of adult viral CAP in China are still lacking. In this study, we analyzed the etiology of adult CAP in Beijing, China and constructed diagnostic models based on combinations of patient clinical factors.

METHODS

A multicenter cohort was established with 500 adult CAP outpatients enrolled in Beijing between November 2010 to October 2011. Multiplex and quantitative real-time fluorescence PCR were used to detect 15 respiratory viruses and mycoplasma pneumoniae, respectively. Bacteria were detected with culture and enzyme immunoassay of the Streptococcus pneumoniae urinary antigen. Univariate analysis, multivariate analysis, discriminatory analysis and Receiver Operating Characteristic (ROC) curves were used to build predictive models for etiological diagnosis of adult CAP.

RESULTS

Pathogens were detected in 54.2% (271/500) of study patients. Viruses accounted for 36.4% (182/500), mycoplasma pneumoniae for 18.0% (90/500) and bacteria for 14.4% (72/500) of the cases. In 182 of the patients with viruses, 219 virus strains were detected, including 166 single and 53 mixed viral infections. Influenza A virus represented the greatest proportion with 42.0% (92/219) and 9.1% (20/219) in single and mixed viral infections, respectively. Factors selected for the predictive etiological diagnostic model of viral CAP included cough, dyspnea, absence of chest pain and white blood cell count (4.0-10.0) × 10(9)/L, and those of mycoplasma pneumoniae CAP were being younger than 45 years old and the absence of a coexisting disease. However, these models showed low accuracy levels for etiological diagnosis (areas under ROC curve for virus and mycoplasma pneumoniae were both 0.61, P < 0.05).

CONCLUSIONS

Greater consideration should be given to viral and mycoplasma pneumoniae infections in adult CAP outpatients. While predictive etiological diagnostic models of viral and mycoplasma pneumoniae based on combinations of demographic and clinical factors may provide indications of etiology, diagnostic confirmation of CAP remains dependent on laboratory pathogen test results.

Viral and bacterial aetiology of community-acquired pneumonia in adults

BACKGROUND

Modern molecular techniques reveal new information on the role of respiratory viruses in community-acquired pneumonia. In this study, we tried to determine the prevalence of respiratory viruses and bacteria in patients with community-acquired pneumonia who were admitted to the hospital.

METHODS

Between April 2008 and April 2009, 408 adult patients (aged between 20 and 94 years) with community-acquired pneumonia were tested for the presence of respiratory pathogens using bacterial cultures, real-time PCR for viruses and bacteria, urinary antigen testing for Legionella and Pneumococci and serology for the presence of viral and bacterial pathogens.

RESULTS

Pathogens were identified in 263 (64·5%) of the 408 patients. The most common single organisms in these 263 patients were Streptococcus pneumoniae (22·8%), Coxiella burnetii (6·8%) and influenza A virus (3·8%). Of the 263 patients detected with pathogens, 117 (44·5%) patients were positive for one or more viral pathogens. Of these 117 patients, 52 (44·4%) had no bacterial pathogen. Multiple virus infections (≥2) were found in 16 patients.

CONCLUSION

In conclusion, respiratory viruses are frequently found in patients with CAP and may therefore play an important role in the aetiology of this disease.

Legionella pneumophila lung abscess associated with immune suppression

Legionella species are a common cause of community-acquired pneumonia, infrequently complicated by cavitary disease. We describe Legionella pneumophila pneumonia and abscess formation in an immunosuppressed patient receiving corticosteroid therapy for metastatic breast carcinoma. The predisposing role of corticosteroids is discussed and the management of this complication is reviewed.

Systematic review and meta-analysis of a urine-based pneumococcal antigen test for diagnosis of community-acquired pneumonia caused by Streptococcus pneumoniae

Standard culture methods for diagnosis of Streptococcus pneumoniae pneumonia take at least 24 h. The BinaxNOW urine-based test for S. pneumoniae (BinaxNOW-SP) takes only 15 min to conduct, potentially enabling earlier diagnosis and targeted treatment. This study was conducted to assess whether the use of BinaxNOW-SP at the time of hospital admission would provide adequate sensitivity and specificity for diagnosis of community-acquired pneumonia (CAP) in adult patients. We searched PubMed, EMBASE/OVID, Cochrane Collaboration, Centre for Reviews and Dissemination, INAHTA, and CADTH for diagnostic or etiologic studies of hospitalized predominately adult patients with clinically defined CAP that reported the diagnostic performance of BinaxNOW-SP versus cultures. Two authors independently extracted study details and diagnostic two-by-two tables. We found that 27 studies met our inclusion criteria, and three different reference standards were used between them. A bivariate meta-analysis of 12 studies using a composite of culture tests as the reference standard estimated the sensitivity of BinaxNOW-SP as 68.5% (95% credibility interval [CrI], 62.6% to 74.2%) and specificity as 84.2% (95% CrI, 77.5% to 89.3%). A meta-analysis of all 27 studies, adjusting for the imperfect and variable nature of the reference standard, gave a higher sensitivity of 74.0% (CrI, 66.6% to 82·3%) and specificity of 97.2% (CrI, 92.7% to 99.8%). The analysis showed substantial heterogeneity across studies, which did not decrease with adjustment for covariates. We concluded that the higher pooled sensitivity (compared to culture) and high specificity of BinaxNOW-SP suggest it would be a useful addition to the diagnostic workup for community-acquired pneumonia. More research is needed regarding the impact of BinaxNOW-SP on clinical practice.

Estimating the burden of pneumococcal pneumonia among adults: a systematic review and meta-analysis of diagnostic techniques

Background

Pneumococcal pneumonia causes significant morbidity and mortality among adults. Given limitations of diagnostic tests for non-bacteremic pneumococcal pneumonia, most studies report the incidence of bacteremic or invasive pneumococcal disease (IPD), and thus, grossly underestimate the pneumococcal pneumonia burden. We aimed to develop a conceptual and quantitative strategy to estimate the non-bacteremic disease burden among adults with community-acquired pneumonia (CAP) using systematic study methods and the availability of a urine antigen assay.

Methods and Findings

We performed a systematic literature review of studies providing information on the relative yield of various diagnostic assays (BinaxNOW® S. pneumoniae urine antigen test (UAT) with blood and/or sputum culture) in diagnosing pneumococcal pneumonia. We estimated the proportion of pneumococcal pneumonia that is bacteremic, the proportion of CAP attributable to pneumococcus, and the additional contribution of the Binax UAT beyond conventional diagnostic techniques, using random effects meta-analytic methods and bootstrapping. We included 35 studies in the analysis, predominantly from developed countries. The estimated proportion of pneumococcal pneumonia that is bacteremic was 24.8% (95% CI: 21.3%, 28.9%). The estimated proportion of CAP attributable to pneumococcus was 27.3% (95% CI: 23.9%, 31.1%). The Binax UAT diagnosed an additional 11.4% (95% CI: 9.6, 13.6%) of CAP beyond conventional techniques. We were limited by the fact that not all patients underwent all diagnostic tests and by the sensitivity and specificity of the diagnostic tests themselves. We address these resulting biases and provide a range of plausible values in order to estimate the burden of pneumococcal pneumonia among adults.

Conclusions

Estimating the adult burden of pneumococcal disease from bacteremic pneumococcal pneumonia data alone significantly underestimates the true burden of disease in adults. For every case of bacteremic pneumococcal pneumonia, we estimate that there are at least 3 additional cases of non-bacteremic pneumococcal pneumonia.

Acute lower respiratory infections in ≥ 5 year -old hospitalized patients in Cambodia, a low-income tropical country: clinical characteristics and pathogenic etiology

Background

Few data exist on viral and bacterial etiology of acute lower respiratory infections (ALRI) in ≥5 year –old persons in the tropics.

Methods

We conducted active surveillance of community-acquired ALRI in two hospitals in Cambodia, a low-income tropical country. Patients were tested for acid-fast bacilli (AFB) by direct sputum examination, other bacteria by blood and/or sputum cultures, and respiratory viruses using molecular techniques on nasopharyngeal/throat swabs. Pulmonologists reviewed clinical/laboratory data and interpreted chest X-rays (CXR) to confirm ALRI.

Results

Between April 2007 - December 2009, 1,904 patients aged ≥5 years were admitted with acute pneumonia (50.4%), lung sequelae-associated ALRI (24.3%), isolated pleural effusions (8.9%) or normal CXR-related ALRI (17.1%); 61 (3.2%) died during hospitalization. The two former diagnoses were predominantly due to bacterial etiologies while viral detection was more frequent in the two latter diagnoses. AFB-positive accounted for 25.6% of acute pneumonia. Of the positive cultures (16.8%), abscess-prone Gram-negative bacteria (39.6%) and Haemophilus influenzae (38.0%) were most frequent, followed by Streptococcus pneumoniae (17.7%). Of the identified viruses, the three most common viruses included rhinoviruses (49.5%), respiratory syncytial virus (17.7%) and influenza viruses (12.1%) regardless of the diagnostic groups. Wheezing was associated with viral identification (31.9% vs. 13.8%, p < 0.001) independent of age and time-to-admission.

Conclusions

High frequency of H. influenzae and S. pneumoniae infections support the need for introduction of the respective vaccines in the national immunization program. Tuberculosis was frequent in patients with acute pneumonia, requiring further investigation. The relationship between respiratory viruses and wheezing merits further studies.

Role of the neutrophil-lymphocyte count ratio in the differential diagnosis between pulmonary tuberculosis and bacterial community-acquired pneumonia

Background

Differential diagnosis between pulmonary tuberculosis (TB) and bacterial community-acquired pneumonia (CAP) is often challenging. The neutrophil-lymphocyte count ratio (NLR), a convenient marker of inflammation, has been demonstrated to be a useful biomarker for predicting bacteremia. We investigated the usefulness of the NLR for discriminating pulmonary TB from bacterial CAP in an intermediate TB-burden country.

Methods

We retrospectively analyzed the clinical and laboratory characteristics of 206 patients suspected of having pulmonary TB or bacterial CAP from January 2009 to February 2011. The diagnostic ability of the NLR for differential diagnosis was evaluated and compared with that of C-reactive protein.

Results

Serum NLR levels were significantly lower in patients with pulmonary TB than in patients with bacterial CAP (3.67±2.12 vs. 14.64±9.72, P<0.001). A NLR <7 was an optimal cut-off value to discriminate patients with pulmonary TB from patients with bacterial CAP (sensitivity 91.1%, specificity 81.9%, positive predictive value 85.7%, negative predictive value 88.5%). The area under the curve for the NLR (0.95, 95% confidence interval [CI], 0.91-0.98) was significantly greater than that of C-reactive protein (0.83, 95% CI, 0.76-0.88; P=0.0015).

Conclusions

The NLR obtained at the initial diagnostic stage is a useful laboratory marker to discriminate patients with pulmonary TB from patients with bacterial CAP in an intermediate TB-burden country.

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.

Evaluation of a rapid test for the diagnosis of pneumococcal pneumonia

We evaluated the usefulness of a rapid immunochromatographic pneumococcal urinary antigen test (UAT) for the diagnosis of pneumonia over a period of five years. The UAT was positive in 32 (2.3%) urine samples obtained from 1414 patients. In 46 of these 1414 patients results of UAT and/or sputum/pleural fluid culture and/or blood culture and/or procalcitonin levels were available and therefore the study was concentrated on these patients. A concordance between UAT positivity and the presence of Streptococcus pneumoniae in the sputum was observed in only 4 of 46 (8.7%) patients for which both urine and sputum samples were analyzed. A discordant result (UAT positive and absence of S. pneumoniae in sputum samples) was recorded in 8 of 46 (17.4 %) patients. UAT negative results with sputum culture positive for S. pneumoniae were recorded in 28.3% of patients. In 20 patients, UAT tested positive but sputum culture was not performed. A concordance between UAT positivity and the isolation of S. pneumoniae from blood was seen in 2 of 46 patients whereas a discordant result (UAT positive and blood culture negative) was seen in 12 (26.1%) patients. A concordance between the UAT and high levels (≥2ng/ml) of procalcitonin was observed in 4 out of 46 patients, whereas a positive UAT result and a procalcitonin negative result were observed in 2 patients. In our experience the UAT allows the detection of the etiological agent of pneumonia, and also when sputum and/or blood cultures are negative for S. pneumoniae, when the clinical picture is suggestive of alveolar pneumonia.

Severity of influenza A 2009 (H1N1) pneumonia is underestimated by routine prediction rules. Results from a prospective, population-based study

BACKGROUND

Characteristics of patients with community-acquired pneumonia (CAP) due to pandemic influenza A 2009 (H1N1) have been inadequately compared to CAP caused by other respiratory pathogens. The performance of prediction rules for CAP during an epidemic with a new infectious agent are unknown.

METHODS

Prospective, population-based study from November 2008-November 2009, in centers representing 70% of hospital beds in Iceland. Patients admitted with CAP underwent evaluation and etiologic testing, including polymerase chain reaction (PCR) for influenza. Data on influenza-like illness in the community and overall hospital admissions were collected. Clinical and laboratory data, including pneumonia severity index (PSI) and CURB-65 of patients with CAP due to H1N1 were compared to those caused by other agents.

RESULTS

Of 338 consecutive and eligible patients 313 (93%) were enrolled. During the pandemic peak, influenza A 2009 (H1N1) patients constituted 38% of admissions due to CAP. These patients were younger, more dyspnoeic and more frequently reported hemoptysis. They had significantly lower severity scores than other patients with CAP (1.23 vs. 1.61, P= .02 for CURB-65, 2.05 vs. 2.87 for PSI, P<.001) and were more likely to require intensive care admission (41% vs. 5%, P<.001) and receive mechanical ventilation (14% vs. 2%, P= .01). Bacterial co-infection was detected in 23% of influenza A 2009 (H1N1) patients with CAP.

CONCLUSIONS

Clinical characteristics of CAP caused by influenza A 2009 (H1N1) differ markedly from CAP caused by other etiologic agents. Commonly used CAP prediction rules often failed to predict admissions to intensive care or need for assisted ventilation in CAP caused by the influenza A 2009 (H1N1) virus, underscoring the importance of clinical acumen under these circumstances.

Viral infection in patients with severe pneumonia requiring intensive care unit admission

RATIONALE

The role of viruses in pneumonia in adults and the impact of viral infection on mortality have not been elucidated. Previous studies have significant limitations in that they relied predominantly on upper respiratory specimens.

OBJECTIVES

To investigate the role of viral infection in adult patients with pneumonia requiring intensive care unit (ICU) admission.

METHODS

A retrospective analysis of a prospective cohort was conducted in a 28-bed medical ICU. Patients with severe community-acquired pneumonia (CAP) or healthcare-associated pneumonia (HCAP) were included in the study.

MEASUREMENTS AND MAIN RESULTS

A total of 198 patients (64 with CAP, 134 with HCAP) were included for analysis. Of these, 115 patients (58.1%) underwent bronchoscopic bronchoalveolar lavage (BAL), 104 of whom were tested for respiratory viruses by BAL fluid reverse-transcription polymerase chain reaction (RT-PCR). Nasopharyngeal specimen RT-PCR was performed in 159 patients (84.1%). Seventy-one patients (35.9%) had a bacterial infection, and 72 patients (36.4%) had a viral infection. Rhinovirus was the most common identified virus (23.6%), followed by parainfluenza virus (20.8%), human metapneumovirus (18.1%), influenza virus (16.7%), and respiratory syncytial virus (13.9%). Respiratory syncytial virus was significantly more common in the CAP group (CAP, 10.9%; HCAP, 2.2%; P = 0.01). The mortalities of patients with bacterial infections, viral infections, and bacterial-viral coinfections were not significantly different (25.5, 26.5, and 33.3%, respectively; P = 0.82).

CONCLUSIONS

Viruses are frequently found in the airway of patients with pneumonia requiring ICU admission and may cause severe forms of pneumonia. Patients with viral infection and bacterial infection had comparable mortality rates.

Aetiology of community-acquired pneumonia among adults in an H1N1 pandemic year: the role of respiratory viruses

This study aimed to determine the aetiology of community-acquired pneumonia (CAP) by adding polymerase chain reaction (PCR) to conventional methods and to describe the clinical and laboratory features between patients with bacterial pneumonia (BP) and viral pneumonia (VP). Adults with CAP admitted from November 2009 to October 2010 were included. Demographics, comorbidities, severity and clinical features were recorded. Conventional microbiological methods included blood and sputum cultures, acute and convalescent serologic samples, and antigen urinary detection. New methods included multiplex PCR for Mycoplasma pneumoniae, Legionella pneumophila, Chlamydophila pneumoniae, Bordetella pertussis and 15 respiratory viruses. A total of 169 patients were included. Using conventional methods, we identified a pathogen in 51 % of cases. With PCR, up to 70 % of cases had an aetiological diagnosis. Forty-five patients had BP (34 %), 22 had VP (17 %) and 25 (19 %) had co-infection (BP and VP). Pneumococci and respiratory syncytial virus (RSV) were the most frequently identified pathogens. Procalcitonin (PCT) and C-reactive protein (CRP) median values were significantly higher in BP than in VP patients. Shaking chills, higher CURB score and shock were significantly more frequent in BP. A viral infection was identified in more than one-third of patients with CAP. Clinical and laboratory features could help to differentiate between VP and BP and to guide empirical therapy.

The impact of bacterial and viral co-infection in severe influenza

BACKGROUND

Many questions remain concerning the burden, risk factors and impact of bacterial and viral co-infection in patients with pandemic influenza admitted to the intensive care unit (ICU).

OBJECTIVES

To examine the burden, risk factors and impact of bacterial and viral co-infection in Australian patients with severe influenza.

PATIENTS/METHODS

A cohort study conducted in 14 ICUs was performed. Patients with proven influenza A during the 2009 influenza season were eligible for inclusion. Demographics, risk factors, clinical data, microbiological data, complications and outcomes were collected. Polymerase chain reaction for additional bacterial and viral respiratory pathogens was performed on stored respiratory samples.

RESULTS

Co-infection was identified in 23·3-26·9% of patients with severe influenza A infection: viral co-infection, 3·2-3·4% and bacterial co-infection, 20·5-24·7%. Staphylococcus aureus was the most frequent bacterial co-infection followed by Streptococcus pneumoniae and Haemophilus influenzae. Patients with co-infection were younger [mean difference in age = 8·46 years (95% CI: 0·18-16·74 years)], less likely to have significant co-morbidities (32·0% versus 66·2%, P = 0·004) and less frequently obese [mean difference in body mass index = 6·86 (95% CI: 1·77-11·96)] compared to those without co-infection.

CONCLUSIONS

 Bacterial or viral co-infection complicated one in four patients admitted to ICU with severe influenza A infection. Despite the co-infected patients being younger and with fewer co-morbidities, no significant difference in outcomes was observed. It is likely that co-infection contributed to a need for ICU admission in those without other risk factors for severe influenza disease. Empiric antibiotics with staphylococcal activity should be strongly considered in all patients with severe influenza A infection.

Doxycycline vs. macrolides in combination therapy for treatment of community-acquired pneumonia

We assessed the comparative efficacy of empirical therapy with beta-lactam plus macrolide vs. beta-lactam plus doxycycline for the treatment of community-acquired pneumonia (CAP) among patients in the Australian Community-Acquired Pneumonia Study. Both regimens demonstrated similar outcomes against CAP due to either 'atypical' (Chlamydophila, Legionella or Mycoplasma spp.) or typical bacterial pathogens.

Comparison of immunoglobulin G subclass concentrations in severe community-acquired pneumonia and severe pandemic 2009 influenza A (H1N1) infection

We compared immunoglobulin G (IgG) subclasses in patients with severe noninfluenza community-acquired pneumonia (CAP) to those in patients with severe pandemic 2009 influenza (H1N1) virus infection. Low IgG1 and IgG2 levels occurred often in the CAP group; however, H1N1 patients had lower IgG1 and IgG2 levels (5.4 versus 3.3 g/liter [P = 0.008] and 2.5 versus 1.2 g/liter [P < 0.001], respectively). Low IgG2 levels may be specifically linked to severe H1N1; however, it is not clear whether this association is related to H1N1 or to other features of severity.

Use of a rapid test of pneumococcal colonization density to diagnose pneumococcal pneumonia

BACKGROUND

There is major need for a more sensitive assay for the diagnosis of pneumococcal community-acquired pneumonia (CAP). We hypothesized that pneumococcal nasopharyngeal (NP) proliferation may lead to microaspiration followed by pneumonia. We therefore tested a quantitative lytA real-time polymerase chain reaction (rtPCR) on NP swab samples from patients with pneumonia and controls.

METHODS

In the absence of a sensitive reference standard, a composite diagnostic standard for pneumococcal pneumonia was considered positive in South African human immunodeficiency virus (HIV)-infected adults hospitalized with radiographically confirmed CAP, if blood culture, induced good-quality sputum culture, Gram stain, or urinary Binax demonstrated pneumococci. Results of quantitative lytA rtPCR in NP swab samples were compared with quantitative colony counts in patients with CAP and 300 HIV-infected asymptomatic controls.

RESULTS

Pneumococci were the leading pathogen identified in 76 of 280 patients with CAP (27.1%) using the composite diagnostic standard. NP colonization density measured by lytA rtPCR correlated with quantitative cultures (r = 0.67; P < .001). The mean lytA rtPCR copy number in patients with pneumococcal pneumonia was 6.0 log(10) copies/mL, compared with patients with CAP outside the composite standard (2.7 log(10) copies/mL; P < .001) and asymptomatic controls (0.8 log(10) copies/mL; P < .001). A lytA rtPCR density ≥8000 copies/mL had a sensitivity of 82.2% and a specificity of 92.0% for distinguishing pneumococcal CAP from asymptomatic colonization. The proportion of CAP cases attributable to pneumococcus increased from 27.1% to 52.5% using that cutoff.

CONCLUSIONS

A rapid molecular assay of NP pneumococcal density performed on an easily available specimen may significantly increase pneumococcal pneumonia diagnoses in adults.

Macrolide resistance in Mycoplasma pneumoniae, Israel, 2010

Macrolide resistance in Mycoplasma pneumoniae is often found in Asia but is rare elsewhere. We report the emergence of macrolide-resistant M. pneumoniae in Israel and the in vivo evolution of such resistance during the treatment of a 6-year-old boy with pneumonia.

Macrolide resistance in Mycoplasma pneumoniae, Israel, 2010

Macrolide resistance in Mycoplasma pneumoniae is often found in Asia but is rare elsewhere. We report the emergence of macrolide-resistant M. pneumoniae in Israel and the in vivo evolution of such resistance during the treatment of a 6-year-old boy with pneumonia.

Guidelines for the management of adult lower respiratory tract infections--full version

This document is an update of Guidelines published in 2005 and now includes scientific publications through to May 2010. It provides evidence-based recommendations for the most common management questions occurring in routine clinical practice in the management of adult patients with LRTI. Topics include management outside hospital, management inside hospital (including community-acquired pneumonia (CAP), acute exacerbations of COPD (AECOPD), acute exacerbations of bronchiectasis) and prevention. Background sections and graded evidence tables are also included. The target audience for the Guideline is thus all those whose routine practice includes the management of adult LRTI.

Clinical and economic burden of community-acquired pneumonia amongst adults in the Asia-Pacific region

Community-acquired pneumonia (CAP) is an important cause of mortality and morbidity amongst adults in the Asia-Pacific region. Literature published between 1990 and May 2010 on the clinical and economic burden of CAP amongst adults in this region was reviewed. CAP is a significant health burden with significant economic impact in this region. Chronic obstructive pulmonary disease, cardiovascular disease, diabetes mellitus and advanced age were risk factors for CAP. Aetiological agents included Streptococcus pneumoniae, Klebsiella pneumoniae, Gram-negative bacteria, Mycobacterium tuberculosis, Burkholderia pseudomallei, Staphylococcus aureus and atypical pathogens (Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella spp.), with important differences in the prevalence of these pathogens within the region. Antibiotic resistance was significant but was not linked to excess mortality. Aetiological pathogens remained susceptible to newer antimicrobial agents. Rational antibiotic use is essential for preventing resistance, and increased surveillance is required to identify future trends in incidence and aetiology and to drive treatment and prevention strategies.

FluCAN 2009: initial results from sentinel surveillance for adult influenza and pneumonia in eight Australian hospitals

OBJECTIVE

To describe the epidemiology of adult patients hospitalised with influenza or pneumonia during a pandemic season in a sentinel network in Australia.

DESIGN, PARTICIPANTS AND SETTING

Prospective case series of adult hospital admissions to eight acute care general public hospitals (Influenza Complications Alert Network [Flu CAN] sentinel hospitals) in six Australian jurisdictions, 1 July to 4 December 2009.

MAIN OUTCOME MEASURES

Demographic, clinical and outcome measures in patients admitted with laboratory-confirmed pandemic (H1N1) 2009 influenza in the sentinel hospitals compared with data from national notifications and intensive care unit (ICU) surveillance; admissions for influenza and pneumonia over time in each jurisdiction.

RESULTS

During 190 hospital-weeks of observation, there were 538 influenza admissions. Of these, 465 patients (86.4%) had the pandemic strain, representing 9.3% of total admissions with pandemic (H1N1) 2009 influenza (n = 4992) recorded nationally in 2009. Of these patients, 250/465 (53.8%) were women, 67/453 (14.8%) were Indigenous, and the median age was 46 years (interquartile range, 29-58 years). Comorbidities were present in 354/464 patients (76.3%), and 40 were pregnant (30.3% of women aged 15-49 years). FluCAN reported that 102 patients (21.9%) were admitted to ICUs, and of patients admitted to hospital, 26 (5.6%) died. FluCAN results were very similar to national notification data and published ICU admissions data. Of those who were followed to 30 days after discharge, 30 (6.5%) were readmitted. Of 1468 patients hospitalised with pneumonia, 718 (48.9%) were tested for influenza and 163 (11.1%) were co-infected with the pandemic strain.

CONCLUSIONS

Sentinel surveillance systems can provide important and reliable information in a timely fashion and can monitor changes in severity of influenza during a pandemic season.

Viral pneumonia

About 200 million cases of viral community-acquired pneumonia occur every year-100 million in children and 100 million in adults. Molecular diagnostic tests have greatly increased our understanding of the role of viruses in pneumonia, and findings indicate that the incidence of viral pneumonia has been underestimated. In children, respiratory syncytial virus, rhinovirus, human metapneumovirus, human bocavirus, and parainfluenza viruses are the agents identified most frequently in both developed and developing countries. Dual viral infections are common, and a third of children have evidence of viral-bacterial co-infection. In adults, viruses are the putative causative agents in a third of cases of community-acquired pneumonia, in particular influenza viruses, rhinoviruses, and coronaviruses. Bacteria continue to have a predominant role in adults with pneumonia. Presence of viral epidemics in the community, patient's age, speed of onset of illness, symptoms, biomarkers, radiographic changes, and response to treatment can help differentiate viral from bacterial pneumonia. However, no clinical algorithm exists that will distinguish clearly the cause of pneumonia. No clear consensus has been reached about whether patients with obvious viral community-acquired pneumonia need to be treated with antibiotics. Apart from neuraminidase inhibitors for pneumonia caused by influenza viruses, there is no clear role for use of specific antivirals to treat viral community-acquired pneumonia. Influenza vaccines are the only available specific preventive measures. Further studies are needed to better understand the cause and pathogenesis of community-acquired pneumonia. Furthermore, regional differences in cause of pneumonia should be investigated, in particular to obtain more data from developing countries.

Community-acquired pneumonia in the central desert and north-western tropics of Australia

BACKGROUND

Community-acquired pneumonia (CAP) results in significant morbidity in central and north-western Australia. However, the nature, management and outcome of CAP are poorly documented. The aim of the study was to describe CAP in the Kimberley and Central Desert regions of Australia.

METHODS

Prospective and retrospective cohort studies of inpatient management of adults with CAP at Alice Springs Hospital and six Kimberley hospitals were carried out. We documented demographic data, comorbidities, investigations, causes, CAP severity, outcome and concordance between prescribed and protocol-recommended antibiotics.

RESULTS

Two hundred and ninety-three subjects were included. Aboriginal Australians were overrepresented (relative risk 8.1). Patients were notably younger (median age 44.5 years) and disease severity lower than in urban Australian settings. Two patients died within 30 days of admission compared with expected mortality based on Pneumonia Severity Index predictions of seven deaths (chi(2), P= 0.09). Disease severity and outcome did not differ between regions. Management differences were identified, including significantly more investigations, higher rates of critical care and broader antibiotic cover in Central Australia compared with the Kimberley. Sputum culture results showed Gram-negative organisms in both regions. However, Streptococcus pneumoniae was the most frequent organism isolated in the Kimberley and Haemophilus influenzae in Central Australia.

CONCLUSION

CAP in this setting is an Aboriginal health issue. The low mortality observed and results of microbiology investigations support the use of existing antibiotic protocols. Larger studies investigating CAP aetiology are warranted. Addressing social and environmental disadvantage remains the key factors in dealing with the burden of CAP in this setting.

Antimicrobial Utilisation in 37 Australian and New Zealand Intensive Care Units

This multi-centre point prevalence study reports on antimicrobial dosing patterns, including dose, mode of administration and type of infection, in 37 Australian and New Zealand intensive care units. Of 422 patients admitted to an intensive care unit on 8 May 2007, 195 patients (46%) received antimicrobial treatment, 123 patients (29%) received no antimicrobials and 104 patients (25%) received prophylactic antimicrobials only. Dosing data were available for 331 antimicrobials used to treat 225 infections in 193 patients. Respiratory (40%), abdominal (13%) and blood stream (12%) infections were most common. For adult patients, ticarcillin/clavulanate (23% or 40/177), meropenem (20% or 35/177) and vancomycin (18% or 32/177) were the most frequently used antibiotics; vancomycin was most commonly used in children (31% or 5/16). The majority of antimicrobials were administered as bolus doses or infusions of less than two hours (98% or 317/323); only six patients received extended or continuous infusions. The mode of administration was unknown in eight cases (4.1%). The total defined daily dose for adult patients receiving antimicrobial therapy was 2051 defined daily doses per 1000 patient days. Our results confirm that the use of continuous infusions remains rare, despite increased interest in continuous infusions for time-dependent antibiotics.

Point of care testing: diagnosis outside the virology laboratory

Numerous point-of-care tests (POCTs) are available to diagnose viral infections in both hospital and community settings. The ideal POCT is rapid, sensitive, specific, and simple to perform. This chapter will describe the benefits of POCTs, factors that can influence the accuracy of POCTs and highlight some limitations of POCT strategies. The sensitivity, specificity, and turn-around time of available POCTs are included for common conditions including respiratory viral infections (e.g. influenza, RSV) and blood-borne viral infections (e.g. HIV).

Vaccine preventable community-acquired pneumonia in hospitalized children in Northwest China

BACKGROUND

Community-acquired pneumonia (CAP) is a major cause of morbidity in industrialized countries and morbidity/mortality in developing countries. In China, comprehensive studies of the etiology of CAP in children aged between 2 months and 14 years who are serious enough to require hospitalization are lacking. Previous studies have been limited in child age range, focused on fatal cases, and/or limited in etiologies sought. An understanding of the etiologies is needed for development of best prevention and management practices.

OBJECTIVE

The aim of this study was to prospectively determine during a 12-month period the etiology of CAP in hospitalized children in a center in Northwest China.

DESIGN/METHODS

A prospective 12-month study (2004-2005) of CAP cases in children who were 2 months to 14 years of age admitted to the Second Hospital of Lanzhou University, China. Testing included admission and 1-month postdischarge serum for viral and bacterial serologic analyses (respiratory syncytial virus, influenza A and B, paraflu 1-3, adenovirus; Streptococcus pneumoniae, Haemophilus influenza B, Mycoplasma, and Moraxella. catarrhalis), blood culture, a nasopharyngeal aspirate for viral antigen testing, and a chest radiograph on admission and 1 month postdischarge. The study was funded by Lanzhou University. The study was performed in compliance with the guidelines of the institutional review board of the Second Hospital of Lanzhou University.

RESULTS

CAP was the admitting diagnosis for 29% of all admissions during the 12-month study. Of the 884 CAP cases, 821 (93%) were enrolled and completed the study. The age range was 2 months to 14 years; mean age was 2.3 years; 40% were <1 year. The average length of stay was 9.2 days (range, 6-20) but varied by age and etiology. Fourteen percent had received antibiotics before admission and 14% had underlying illnesses; 12% required intensive care unit treatment and 5 died. A microbial etiology for CAP was identified in 547 (67%); viral 535 (43%), bacterial 228 (27%), mixed viral bacterial 107 (13%), mixed viral in 1%, and mixed bacterial in 1%. The etiology varied by age; respiratory syncytial virus was most common in <1 year, S. pneumoniae and Hib 1-3 years, and Mycoplasma 5 years. Three potentially vaccine preventable etiologies accounted for 35% of the cases: influenza 9%, Hib 12%, and S. pneumonia 14%.

CONCLUSIONS

CAP is a major cause of childhood admission in China. Given the etiologic findings in this study, potentially 25% to 35% of cases could be prevented if seasonal influenza vaccine and conjugated H. influenza b and conjugated pneumococcal vaccines were introduced into routine practice.

Outcomes of hospitalized patients with bacteraemic and non-bacteraemic community-acquired pneumonia caused by Streptococcus pneumoniae

In contrast to bacteraemic pneumococcal community-acquired pneumonia (CAP), there is a paucity of data on the clinical characteristics and outcomes of non-bacteraemic pneumococcal CAP. This retrospective study compared the outcome of hospitalized patients with bacteraemic and non-bacteraemic pneumococcal CAP treated at a medical centre from 2004 to 2008. Data on clinical outcomes including all-cause mortality, length of hospital stay, need for intensive-care unit admission and extrapulmonary involvement were analysed. In all, 221 patients with pneumococcal pneumonia (87 bacteraemic, 134 non-bacteraemic) were included. Patients with bacteraemic pneumococcal pneumonia (BPP) were older than those with non-BPP (46·2 ± 30·7 years vs. 21·7 ± 30·8 years, P<0·001) and were more likely to have underlying medical diseases (66·7% vs. 33·6%, P<0·001). The overall mortality rates at 7, 14, and 30 days were significantly higher in BPP than non-BPP patients (12·6% vs. 2·2%, 14·9% vs. 3·7%, 19·5% vs. 5·1%, all P<0·01). Multivariate logistic regression analysis showed that pneumococcal bacteraemia was correlated with extrapulmonary involvement (odds ratio 5·46, 95% confidence interval 1·97-15·16, P=0·001). In conclusion, S. pneumoniae bacteraemia increased the risk of mortality and extrapulmonary involvement in patients with pneumococcal CAP.

Community-acquired pneumonia in the elderly

BACKGROUND

Community-acquired pneumonia (CAP) is a frequent cause of hospitalization and death among the elderly.

OBJECTIVE

This article reviews information on CAP among the elderly, including age-related changes, predisposing risk factors, causes, treatment strategies, and prevention.

METHODS

Searches of MEDLINE (January 1990-November 2009), International Pharmaceutical Abstracts (January 1990-November 2009), and Google Scholar were conducted using the terms community-acquired pneumonia, pneumonia, treatment guidelines, and elderly. Additional publications were found by searching the reference lists of the identified articles. Studies that reported diagnostic criteria as well as the treatment outcomes achieved in adult patients with CAP were selected for this review.

RESULTS

Three practice guidelines, 5 reviews, and 43 studies on CAP in the elderly were identified in the literature search. Based on those publications, risk factors that predispose the elderly to pneumonia include comorbid conditions, poor functional and nutritional status, consumption of alcohol, and smoking. The clinical presentation of pneumonia in the elderly (>/=65 years of age) may be subtle, lacking the typical acute symptoms (fever, cough, dyspnea, and purulent sputum) observed in younger adults. Pneumonia should be suspected in all elderly patients who have fever, altered mental status, or a sudden decline in functional status, with or without lower respiratory tract symptoms such as cough, purulent sputum, and dyspnea. Treatment of CAP in the elderly should be guided by the latest recommendations of the Infectious Diseases Society of America and the American Thoracic Society (IDSA/ATS), along with consideration of local rates and patterns of antimicrobial resistance, as well as individual patient risk factors for acquiring less common or more resistant pathogens. Recommended empiric antimicrobial regimens generally consist of either a beta-lactam plus a macrolide or a respiratory fluoroquinolone alone. Adherence to the IDSA/ATS guidelines has been found to improve in-hospital mortality (adherence vs nonadherence, 8%; 95% CI, 7%-10% vs 17%; 95% CI, 14%-20%; P< 0.01), length of hospital stay (8 days; interquartile range [IQR], 5-15 vs 10 days; IQR, 6-24 days, respectively; P < 0.01), and time to clinical stability in elderly patients with CAP (percentage of stable patients by day 7, 71%; 95% CI, 68%-74% vs 57%; 95% CI, 53%-61%, respectively; P < 0.01). All elderly patients should be vaccinated against pneumococcal disease and influenza based on recommendations from the Centers for Disease Control and Prevention. Lifestyle modifications and nutritional support are also important elements in the prevention of pneumonia in the elderly.

CONCLUSION

Adherence to established guidelines, along with customization of antimicrobial therapy based on local rates and patterns of resistance and patient-specific risk factors, likely will improve the treatment outcome of elderly patients with CAP.

Reduction in hospitalizations for pneumonia associated with the introduction of a pneumococcal conjugate vaccination schedule without a booster dose in Australia

BACKGROUND

Postmarketing surveillance of heptavalent pneumococcal conjugate vaccine (7vPCV) has shown significant reductions in admissions coded as pneumonia in countries where a booster dose is given in the second year of life. In Australia, a 3-dose primary schedule at 2, 4, and 6 months of age without a booster has been funded nationally for non-Indigenous children since 2005.

METHODS

All hospital discharges in Australia with the primary diagnosis coded as pneumonia between July 1998 and June 2007 were identified from a national electronic database. Monthly rates of hospitalization for pneumonia over this period were determined for the age groups < 2, 2-4,5-17, 18-39, 40-64, and > or = 65 years. Negative binomial regression modeling,adjusting for background and seasonal trends, was used to quantify the effect of the 7vPCV program.

RESULTS

A total of 523,591 eligible hospital discharges were identified. In the 30 months following 7vPCV introduction, there were significant adjusted reductions in all-cause pneumonia in children aged < 2 and 2 to 4 years of 38%(95% CI 36%-40%), and 29% (26%-31%), respectively. Reductions of between 3% and 11% were observed in the older age groups.

INTERPRETATION

The significant differential effects observed are strongly suggestive of the PCV7 program being responsible for the observed reduction in pneumonia hospitalizations in Australia, and the magnitude was comparable to that documented in countries with a booster dose. This finding appears robust and may be related to high levels of vaccination coverage and catch-up early in the program, or to relatively lower levels of serotype replacement without a booster dose.

Pneumonia risk stratification in tropical Australia: does the SMART-COP score apply?

OBJECTIVE

To examine the performance in tropical northern Australia of SMART-COP, a simple scoring system developed in temperate Australia to predict the need for intensive respiratory or vasopressor support (IRVS) in pneumonia patients.

DESIGN, SETTING AND PATIENTS

A prospective observational study of patients admitted to Royal Darwin Hospital in the Northern Territory with sepsis between August 2007 and May 2008. Chest x-rays were reviewed to confirm pneumonia, and each patient's SMART-COP score was assessed against the need for IRVS.

RESULTS

Of 206 patients presenting with radiologically confirmed pneumonia, 184 were eligible for inclusion. The mean age of patients was 50.1 years, 65% were Indigenous and 56% were men. Overall, 38 patients (21%) required IRVS, and 18 patients (10%) died by Day 30. A SMART-COP score of >or= 3 had a sensitivity of only 71% for predicting the need for IRVS and 67% for 30-day mortality. As the variables most strongly associated with IRVS were serum albumin level < 35 g/L (odds ratio, 6.8) and Indigenous status (odds ratio, 2.3), we tested a modified scoring system (SMART-COP) that used a higher weighting for albumin and included Indigenous status. A SMART-COP score of >or= 3 had a sensitivity of 97% for IRVS and 100% for 30-day mortality.

CONCLUSIONS

The SMART-COP score underestimates the severity of pneumonia in tropical northern Australia, but can be improved by using locally relevant additions.

Community acquired bacterial pneumonia

IMPORTANCE OF THE FIELD

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

AREAS COVERED IN THIS REVIEW

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

WHAT THE READER WILL GAIN

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

TAKE HOME MESSAGE

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

Atypical pneumonia--time to breathe new life into a useful term?

The term atypical pneumonia was originally used to describe an unusual presentation of pneumonia. It is now more widely used in reference to either pneumonia caused by a relatively common group of pathogens, or to a distinct clinical syndrome the existence of which is difficult to demonstrate. As such, the use of atypical pneumonia is often inaccurate, potentially confusing, and of dubious scientific merit. We need to return to the original meaning of atypical pneumonia and restrict its use to describe pneumonia that is truly unusual in clinical presentation, epidemiology, or both.

Safety and Efficacy Review of Doxycycline

Doxycycline is a member of the tetracycline class of antibiotics and has been used clinically for more than 40 years. It is a well-tolerated drug that is bacteriostatic and acts via the inhibition of bacterial ribosomes. It is generally given at a dose of 100-mg daily or twice daily. It is well absorbed and has generally good tissue penetration. The serum half-life is 18-22 hours and dosage does not need to be adjusted in the presence of renal or hepatic impairment. Major side effects are gastro-intestinal and dermatological and it is generally contra-indicated in pregnancy or childhood because of concerns about discolouration of developing teeth and potential effects on growing bones. Drug interactions are not common although can occur with the concomitant use of methotrexate and the oral contraceptive pill, and its absorption can be reduced by the co-administration with some antacids and iron preparations. It has activity against many organisms, including Gram-positives, Gram-negatives and atypical bacteria. In addition, it appears to have some potentially clinically useful anti-inflammatory properties.