Etiology of community-acquired pneumonia: impact of age, comorbidity, and severity

Childhood Hib vaccination and pneumonia and influenza burden in US seniors

This analysis examines the potential for the elderly to receive indirect protection from pneumonia and influenza (P&I) from vaccination of children. Using data from the Centers for Medicare and Medicaid Services, the National Immunization Survey, and the Behavioral Risk Factor Surveillance System, mixed-effects models were used to assess associations between vaccination coverage and P&I on the state level overall and by urbanicity and income. As vaccination coverage in children increased, the state-level P&I rates in seniors decreased (beta=-0.040, -0.074 to 0.006), where beta represents the expected change in the logged age-associated rate of disease increase for a one-percentage point increase in vaccination coverage. Increasing vaccination coverage in the elderly was associated with an increase in P&I rates (beta=0.045, 0.011-0.077) in seniors. The degree of association was more prominent in urban and high income areas. The consistent associations between influenza in the elderly and vaccination coverage in children suggest that routine vaccination of children may impart some indirect protection to the elderly.

Nanomedicine for respiratory diseases

Treatment of respiratory diseases and infections has proved to be a challenging task, with the incidence of these ailments increasing worldwide. Nanotechnology-based drug and gene delivery systems offer a possible solution to some of the shortfalls of the current treatment regimen. Nanobased drug delivery systems have revolutionised the field of pharmacotherapy by presenting the ability to alter the pharmacokinetics of the conventional drugs to extend the drug retention time, reduce the toxicity and increase the half-life of the drugs. Delivery of exogenous genes to the airway epithelium in vivo has been limited by several physiological barriers, resulting in the low success rate of these systems. With the advent of nanotechnology, DNA compacted with cationic polymers to produce nanoparticles has exhibited a significant increase in the transfection efficiencies. With nanoparticulate drug/gene delivery systems, specific cells can be targeted by functionalising the polymeric nanoparticles with ligands that allow the particles to dock at a specific site of the cell. In addition, polymeric systems allow for the cargo to be released in a controlled and stimuli-responsive manner. The advantages that nanoparticulate delivery systems present in the treatment of respiratory diseases and infections are summarised in this review.

Etiology of community-acquired pneumonia: increased microbiological yield with new diagnostic methods

BACKGROUND

The microbial etiology of community-acquired pneumonia (CAP) is still not well characterized. During the past few years, polymerase chain reaction (PCR)-based methods have been developed for many pathogens causing respiratory tract infections. The aim of this study was to determine the etiology of CAP among adults-especially the occurrence of mixed infections among patients with CAP-by implementing a new diagnostic PCR platform combined with conventional methods.

METHODS

Adults admitted to Karolinska University Hospital were studied prospectively during a 12-month period. Microbiological testing methods included culture from blood, sputum, and nasopharyngeal secretion samples; sputum samples analyzed by real-time quantitative PCR for Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis; nasopharyngeal specimens analyzed by use of PCR; serological testing for Mycoplasma pneumoniae, Chlamydophila pneumoniae, and viruses common in the respiratory tract; and urine antigen assays for detection of pneumococcal and Legionella pneumophila antigens.

RESULTS

A microbial etiology could be identified for 67% of the patients (n = 124). For patients with complete sampling, a microbiological agent was identified for 89% of the cases. The most frequently detected pathogens were S. pneumoniae (70 patients [38%]) and respiratory virus (53 patients [29%]). Two or more pathogens were present in 43 (35%) of 124 cases with a determined etiology.

CONCLUSIONS

By supplementing traditional diagnostic methods with new PCR-based methods, a high microbial yield was achieved. This was especially evident for patients with complete sampling. Mixed infections were frequent (most commonly S. pneumoniae together with a respiratory virus).

Staphylococcus aureus community-onset pneumonia in patients admitted to children's hospitals during autumn and winter of 2006-2007

Staphylococcus aureus is a relatively uncommon cause of community-onset pneumonia (COP) that may complicate influenza infection. We reviewed admissions to children's hospitals to describe more systematically this entity. Records of patients hospitalized at three children's hospitals between 1 October 2006 and 30 April 2007 who had a positive S. aureus culture from a sterile site or respiratory specimen were reviewed and data were abstracted for episodes of primary S. aureus COP. Overall, 30 episodes met criteria for primary S. aureus COP; 12 (41%) involved methicillin-resistant S. aureus. Patients in 11 (37%) episodes were seen by a healthcare provider for their symptoms prior to hospital admission; three received an antimicrobial, none of which had activity against the S. aureus isolated. Mechanical ventilation was required in 21 (70%) episodes; five (17%) patients died. When evaluating patients with severe COP, providers should be aware of the potential for S. aureus, including methicillin-resistant strains.

Clinical and molecular epidemiology of human rhinovirus C in children and adults in Hong Kong reveals a possible distinct human rhinovirus C subgroup

BackgroundA novel human rhinovirus (HRV) species, HRV-C, was recently discovered, but its clinical features and epidemiology, compared with HRV-A and HRV-B, remains poorly understood, especially in adults

MethodsOne thousand two hundred nasopharyngeal aspirate samples obtained from hospitalized children and adults during a 1-year period were subject to reverse-transcriptase polymerase chain reaction to detect HRV. The clinical and molecular epidemiology of the 3 HRV species was analyzed

ResultsHRVs were detected in 178 (29.7%) of 600 nasopharyngeal aspirate samples from children and 42 (7%) of 600 nasopharyngeal aspirate samples from adults. HRV-A was most prevalent (n=111), followed by HRV-C (n=91) and HRV-B (n=18). Although upper respiratory tract infection was the most common presentation in children, 8 (62%) of the 13 adults with HRV-C infection had pneumonia, compared with 6 (27%) of the 22 adults with HRV-A infection (P<.05). Wheezing episodes were also more common among individuals with HRV-C (37%) and HRV-A (20%) infection than among those with HRV-B (0%) infection (P<.05). Clinical and molecular data analysis revealed HRV-C as a frequent cause of community and institutionalized outbreaks. A diverse set of HRV-C genotypes was circulating throughout the year, among which a potential distinct subgroup of strains was observed

ConclusionHRV-C is associated with pneumonia in adults and outbreaks of respiratory infections requiring hospitalization. A potential novel HRV-C subgroup was identified

[Swallowing disorders, pneumonia and respiratory tract infectious disease in the elderly]

Swallowing disorders (or dysphagia) are common in the elderly and their prevalence is often underestimated. They may result in serious complications including dehydration, malnutrition, airway obstruction, aspiration pneumonia (infectious process) or pneumonitis (chemical injury caused by the inhalation of sterile gastric contents). Moreover the repercussions of dysphagia are not only physical but also emotional and social, leading to depression, altered quality of life, and social isolation. While some changes in swallowing may be a natural result of aging, dysphagia in the elderly is mainly due to central nervous system diseases such as stroke, parkinsonism, dementia, medications, local oral and oesophageal factors. To be effective, management requires a multidisciplinary team approach and a careful assessment of the patient's oropharyngeal anatomy and physiology, medical and nutritional status, cognition, language and behaviour. Clinical evaluation can be completed by a videofluoroscopic study which enables observation of bolus movement and movements of the oral cavity, pharynx and larynx throughout the swallow. The treatment depends on the underlying cause, extent of dysphagia and prognosis. Various categories of treatment are available, including compensatory strategies (postural changes and dietary modification), direct or indirect therapy techniques (swallow manoeuvres, medication and surgical procedures).

Prevalence of human metapneumovirus in hospitalized children with respiratory tract infections in Tianjin, China

Human metapneumovirus (hMPV) has recently been recognized as an important respiratory pathogen, especially in children. At present, our understanding of the characteristics of hMPV from China is very limited. Nasopharyngeal aspirates were taken from 310 hospitalized pediatric patients. Twenty (6.5%) of them were infected with hMPV, and they all developed pneumonia. Sixty five percent (13/20) of the cases were under 12 months. Phylogenetic analysis of F gene fragments indicated that three sub-genotypes of hMPV(A2a/A2b, B1,B2) circulated in Tianjin and A2b was the predominant subtype. The Vero-E6 cell line was better than LLC-MK2 for hMPV isolation. Three hMPV strains were successfully isolated using the Vero-E6 cell line.

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.

Nontypeable Haemophilus influenzae clearance by alveolar macrophages is impaired by exposure to cigarette smoke

Nontypeable Haemophilus influenzae (NTHI) is an opportunistic gram-negative pathogen that causes respiratory infections and is associated with progression of respiratory diseases. Cigarette smoke is a main risk factor for development of respiratory infections and chronic respiratory diseases. Glucocorticoids, which are anti-inflammatory drugs, are still the most common therapy for these diseases. Alveolar macrophages are professional phagocytes that reside in the lung and are responsible for clearing infections by the action of their phagolysosomal machinery and promotion of local inflammation. In this study, we dissected the interaction between NTHI and alveolar macrophages and the effect of cigarette smoke on this interaction. We showed that alveolar macrophages clear NTHI infections by adhesion, phagocytosis, and phagolysosomal processing of the pathogen. Bacterial uptake requires host actin polymerization, the integrity of plasma membrane lipid rafts, and activation of the phosphatidylinositol 3-kinase (PI3K) signaling cascade. Parallel to bacterial clearance, macrophages secrete tumor necrosis factor alpha (TNF-alpha) upon NTHI infection. In contrast, exposure to cigarette smoke extract (CSE) impaired alveolar macrophage phagocytosis, although NTHI-induced TNF-alpha secretion was not abrogated. Mechanistically, our data showed that CSE reduced PI3K signaling activation triggered by NTHI. Treatment of CSE-exposed cells with the glucocorticoid dexamethasone reduced the amount of TNF-alpha secreted upon NTHI infection but did not compensate for CSE-dependent phagocytic impairment. The deleterious effect of cigarette smoke was observed in macrophage cell lines and in human alveolar macrophages obtained from smokers and from patients with chronic obstructive pulmonary disease.

Molecular characterization of viruses from clinical respiratory samples producing unidentified cytopathic effects in cell culture

The sequence-independent single primer amplification (SISPA) method was performed to identify a virus in 17 clinical respiratory samples producing uncharacterized cytopathic effects in LLC-MK2 cells. Sequence analysis of 600-1600 bp amplicons allowed the identification of six viruses (one influenza C, two parechovirus-3 and three cardioviruses). Genomic sequences of the cardioviruses showed similarities with those of the recently-described Saffold virus strain although significant variation was present in the viral surface EF and CD loops. These results demonstrate the usefulness of SISPA for identifying emerging viruses and also known viruses not easily identified by standard virological methods.

Increasing incidence of legionellosis in the United States, 1990-2005: changing epidemiologic trends

BACKGROUND

An abrupt increase in the incidence of legionellosis in the United States has been noted since 2003. Whether the recent increase is associated with shifting epidemiologic trends has not been well characterized.

METHODS

We analyzed all cases of legionellosis reported to the Centers for Disease Control and Prevention through the National Notifiable Disease Surveillance System from 1990 through 2005.

RESULTS

A total of 23,076 cases of legionellosis were reported to the Centers for Disease Control and Prevention from 1990 through 2005. The number of reported cases increased by 70% from 1310 cases in 2002 to 2223 cases in 2003, with a sustained increase to >2000 cases per year from 2003 through 2005. The eastern United States showed most of the increases in age-adjusted incidence rates after 2002, with the mean rate in the Middle Atlantic states during 2003-2005 exceeding that during 1990-2002 by 96%. During 2000-2005, legionellosis cases were most commonly reported in persons aged 45-64 years. Persons aged <65 years comprised 63% of total cases in 2000-2005. Age-adjusted incidence rates in males exceeded those in females for all age groups and years. Legionellosis incidence showed marked seasonality in eastern states, with most cases reported in the summer or fall.

CONCLUSIONS

Reported legionellosis cases have increased substantially in recent years, particularly in the eastern United States and among middle-aged adults. Legionella infection should be considered in the differential diagnosis of any patient with pneumonia. Public health professionals should focus increased attention on detection and prevention of this important and increasing public health problem.

Mycoplasma pneumoniae pneumonia revisited within the German Competence Network for Community-acquired pneumonia (CAPNETZ)

BACKGROUND

Currently, broad empiric antimicrobial treatment including atypical coverage is recommended for patients with mild to moderate community-acquired pneumonia (CAP). Therefore, the relative impact of each atypical pathogen, particularly Mycoplasma pneumoniae deserves renewed attention.

METHODS

Based on prospective data from 4532 patients with CAP included in the German CAP-Competence Network (CAPNETZ), we studied the incidence, clinical characteristics, and outcome of patients with Mycoplasma pneumoniae pneumonia (MPP). The diagnosis of MPP was based on a positive PCR from respiratory samples and/or a positive IgM-titer from an acute phase serum sample.

RESULTS

307 patients (6.8%) had definite MPP (148 with positive PCR, 204 with positive IgM, 46 with positive PCR and IgM). Compared to patients with other definite and unknown etiologies, patients with MPP were significantly younger (41 +/- 16 versus 62 +/- 17 and 61 +/- 18 years), had fewer co-morbidities, presented with a less severe disease, showed a lower inflammatory response in terms of leukocyte counts (median 8850 versus 13200 and 11000 microL) and CRP values (60 versus 173 and 73 mg/L), and had better outcomes, including a shorter length of hospitalization (9 +/- 5 versus 14 +/- 11 and 12 +/- 9 days), fewer patients requiring mechanical ventilation (0.3 versus 4.5 and 2.1%), and a minimal mortality (0.7 versus 8.7 and 6.5%).

CONCLUSION

In this large series of patients with definite MPP according to very strict criteria, MPP appears as a condition with a high incidence, quite specific clinical presentation, and a largely benign course. In view of a widely favorable clinical outcome, recent recommendations including regular coverage of atypical pathogens in patients with mild to moderate CAP might be reconsidered for patients in Germany as well as in other countries with comparable epidemiological settings.

Risk factors and outcome of community-acquired pneumonia due to Gram-negative bacilli

BACKGROUND AND OBJECTIVE

Several sets of guidelines have advocated initial antibiotic treatment for community-acquired pneumonia due to Gram-negative bacilli in patients with specific risk factors. However, evidence to support this recommendation is scarce. We sought to identify risk factors for community-acquired pneumonia due to Gram-negative bacilli, including Pseudomonas aeruginosa, and to assess outcomes.

METHODS

An observational analysis was carried out on prospectively collected data for immunocompetent adults hospitalized for community-acquired pneumonia in two acute-care hospitals. Cases of pneumonia due to Gram-negative bacilli were compared with those of non-Gram-negative bacilli causes.

RESULTS

Sixty-one (2%) of 3272 episodes of community-acquired pneumonia were due to Gram-negative bacilli. COPD (odds ratio (OR) 2.4, 95% confidence interval (CI): 1.2-5.1), current use of corticosteroids (OR 2.8, 95% CI: 1.2-6.3), prior antibiotic therapy (OR 2.6, 95% CI: 1.4-4.8), tachypnoea >or=30 cycles/min (OR 2.1, 95% CI: 1.1-4.2) and septic shock at presentation (OR 6.1, 95% CI: 2.5-14.6) were independently associated with Gram-negative bacilli pneumonia. Initial antibiotic therapy in patients with pneumonia due to Gram-negative bacilli was often inappropriate. These patients were also more likely to require admission to the intensive care unit, had longer hospital stays, and higher early (<48 h) (21% vs 2%; P < 0.001) and overall mortality (36% vs 7%; P < 0.001).

CONCLUSIONS

These results suggest that community-acquired pneumonia due to Gram-negative bacilli is uncommon, but is associated with a poor outcome. The risk factors identified in this study should be considered when selecting initial antibiotic therapy for patients with community-acquired pneumonia.

The systemic and pulmonary LPS binding protein response to intratracheal lipopolysaccharide

LPS binding protein (LBP) is an acute-phase glycoprotein that facilitates LPS activation of immune cells through interactions with CD14 and Toll-like receptor 4. Initially, LBP production was thought to occur exclusively in the liver in response to stimulation with TNF-alpha, IL-1, and IL-6. More recently, it has been shown that type II pneumocytes are also capable of LBP production. Little is known, however, regarding the regulation and or distribution of this protein in response to localized intrapulmonary infection. We performed time-course experiments challenging C3H mice intratracheally with LPS (10 mug). In separate experiments, mice deficient in IL-6 were given the same dose of intratracheal LPS and euthanized 8 h later. Despite the intratracheal route of LPS administration, an increase in plasma LBP concentrations occurred earlier and was of greater magnitude than the increase observed in bronchoalveolar lavage fluid. Liver LBP mRNA increased to a greater extent than did lung LBP mRNA. Whereas the TNF-alpha response remained localized within the alveolar space, IL-6 was increased both locally and in plasma. Of several tissues analyzed, the lung was the greatest producer of IL-6 mRNA. Plasma LBP was significantly decreased in the IL-6-deficient mice compared with wild-type controls challenged with intratracheal LPS. We conclude that lung-derived IL-6 is an important mediator of hepatic LBP up-regulation. We speculate that the disruption of these lung-liver signaling pathways may be important to host response efforts to confine infection to the lung. If impaired, this may be one mechanism underlying the increased mortality observed in patients with liver disease who develop pneumonia.

Causative agent distribution and antibiotic therapy assessment among adult patients with community acquired pneumonia in Chinese urban population

BACKGROUND

Knowledge of predominant microbial patterns in community-acquired pneumonia (CAP) constitutes the basis for initial decisions about empirical antimicrobial treatment, so a prospective study was performed during 2003-2004 among CAP of adult Chinese urban populations.

METHODS

Qualified patients were enrolled and screened for bacterial, atypical, and viral pathogens by sputum and/or blood culturing, and by antibody seroconversion test. Antibiotic treatment and patient outcome were also assessed.

RESULTS

Non-viral pathogens were found in 324/610 (53.1%) patients among whom M. pneumoniae was the most prevalent (126/610, 20.7%). Atypical pathogens were identified in 62/195 (31.8%) patients carrying bacterial pathogens. Respiratory viruses were identified in 35 (19%) of 184 randomly selected patients with adenovirus being the most common (16/184, 8.7%). The nonsusceptibility of S. pneumoniae to penicillin and azithromycin was 22.2% (Resistance (R): 3.2%, Intermediate (I): 19.0%) and 79.4% (R: 79.4%, I: 0%), respectively. Of patients (312) from whom causative pathogens were identified and antibiotic treatments were recorded, clinical cure rate with beta-lactam antibiotics alone and with combination of a beta-lactam plus a macrolide or with fluoroquinolones was 63.7% (79/124) and 67%(126/188), respectively. For patients having mixed M. pneumoniae and/or C. pneumoniae infections, a better cure rate was observed with regimens that are active against atypical pathogens (e.g. a beta-lactam plus a macrolide, or a fluoroquinolone) than with beta-lactam alone (75.8% vs. 42.9%, p = 0.045).

CONCLUSION

In Chinese adult CAP patients, M. pneumoniae was the most prevalent with mixed infections containing atypical pathogens being frequently observed. With S. pneumoniae, the prevalence of macrolide resistance was high and penicillin resistance low compared with data reported in other regions.

Alcohol use disorder and perioperative immune dysfunction

The anesthesiological sequelae of long-term alcohol abuse include a three to fivefold increased risk of postoperative infection, prolonged intensive care unit stays and longer hospital stays. The cause of the higher infection rates is an altered immune response in long-term alcoholic patients. Preoperatively, the T helper cells 1 to T helper cells 2 ratio is depressed in long-term alcoholic patients and remains suppressed after surgery. The lower preoperative T helper cells 1 to T helper cells 2 ratio is predictive of later onset of infections. Postoperatively, the cytotoxic lymphocyte (Tc1/Tc2) ratio is decreased in long-term alcoholic patients and remains depressed for 5 days. The interleukin (IL)-6/IL-10 ratio and the lipopolysaccharide-stimulated interferon gamma/IL-10 ratio in whole blood cells are decreased after surgery in long-term alcoholic patients. Depressed Tc1/Tc2, IL-6/IL-10 and lipopolysaccharide-stimulated interferon gamma/IL-10 ratios in the postoperative period are predictive of subsequent postoperative infections. Perioperative interventions should aim to minimize dysregulation of the immune system.

Pneumonia in the elderly: a review of the epidemiology, pathogenesis, microbiology, and clinical features

Pneumonia is a common and important disease in the elderly. The incidence is expected to rise as the population ages, and, therefore, it will become an increasingly significant problem in hospitals and the community. A comprehensive literature review was performed in order to look at the characteristics of pneumonia in the elderly population. In particular, the epidemiology, etiology and pathogenesis--including risk factors, microbiology, and clinical features--were evaluated. While aging causes physiological changes which make elderly patients more susceptible to pneumonia, it was found that comorbidities, rather than age, are also an important risk factor. The most common micro-organism responsible for pneumonia is Streptococcus pneumoniae, but other organisms need to be considered, depending on the environment of presentation. Elderly patients are more likely than younger adults to present with an absence of fever and an altered mental state. Nursing home residents tend to present with more atypical and less characteristic symptoms.

Clinical features predicting failure of pathogen identification in patients with community acquired pneumonia

Community acquired pneumonia (CAP) is caused by a variety of microorganisms. By identifying patients at risk for failure of pathogen identification, it is possible to make an early decision on the extent of diagnostic procedures to be performed. This is especially important in patients with severe CAP. The aim of this study was to identify these patients by using clinical and laboratory features. In 201 patients hospitalized for CAP, clinical and laboratory variables were collected. Pathogen identification was performed by culture of sputum and blood, urine antigen tests, polymerase chain reaction of sputum, serological testing and viral culture of the pharynx. In 128 patients a respiratory microorganism was identified. In both univariate and multivariate analysis, failure of pathogen identification was predicted by pre-hospital antibiotic therapy, a medical history of hypertension and a low C-reactive protein. We conclude that patients with pre-hospital antibiotic therapy, a medical history of hypertension and a relatively low C-reactive protein are at risk for failure of pathogen identification. These predictors should be confirmed in a larger population. Invasive testing in high-risk patients with CAP in the presence of these predictors should be considered at an early phase of hospitalization.

Community-acquired pneumonia in elderly patients

Community-acquired pneumonia continues to have a significant impact on elderly individuals, who are affected more frequently and with more severe consequences than younger populations. As the population ages it is expected that the medical and economic impact of this disease will increase. Despite these concerns, little progress has been made in research specifically focusing on community-acquired pneumonia in the elderly. Data continue to show that a high index of suspicion, early antimicrobial therapy and appropriate medications to cover typical pathogens are extremely important in treating community-acquired pneumonia in older individuals. This review is designed to serve as an update to our previous work published in Aging Health in 2006, with specific emphasis on the most recent evidence published since that time.

Review: Novel targets in the management of pneumonia

Community-acquired pneumonia (CAP) is the leading cause of death from infectious diseases in the US. It accounts each year for 500,000 hospitalizations and 45,000 deaths and represents one of the most common causes of intensive care unit (ICU) admission. The mortality rate due to severe CAP has shown little improvement in the past three decades, remaining between 21% and 58% in patients admitted to the intensive care unit. Antimicrobial agents are the cornerstone of therapy against CAP, but there are some novel antibiotic and nonantibiotic therapies that have been recently tested that may potentially impact outcomes of patients with severe CAP. We will review the most recent data regarding novel therapies in patients with the highest risk of death such as those with severe CAP.

Improving outcomes of elderly patients with community-acquired pneumonia

Community-acquired pneumonia (CAP) is a major cause of morbidity and mortality in elderly patients. Therefore, efforts to optimize the healthcare process for patients with CAP are warranted. An organized approach to management is likely to improve clinical results. Assessing the severity of CAP is crucial to predicting outcome, deciding the site of care, and selecting appropriate empirical therapy. Unfortunately, current prognostic scoring systems for CAP such as CURB-65 (confusion, uraemia, respiratory rate, low blood pressure and 65 years of age) or the Pneumonia Severity Index have not been validated specifically in older adults, in whom assessment of mortality risk alone might not be adequate for predicting outcomes. Obtaining a microbial diagnosis remains problematic and may be particularly challenging in frail elderly persons, who may have greater difficulties producing sputum. Effective empirical treatment involves selection of a regimen with a spectrum of activity that includes the causative pathogen. Although most cases of CAP are probably caused by a single pathogen, dual and multiple infections are increasingly being reported. Streptococcus pneumoniae remains the overriding aetiological agent, particularly in very elderly people. However, respiratory viruses and 'atypical' organisms such as Chlamydia pneumoniae are being described with increasing frequency in old patients, and aspiration pneumonia should also be taken into consideration, particularly in very elderly subjects and those with dementia. Age >65 years is a well established risk factor for infection with drug-resistant S. pneumoniae. Clinicians should be aware of additional risk factors for acquiring less common pathogens or antibacterial-resistant organisms that may suggest that additions or modifications to the basic empirical regimen are warranted. In addition to administration of antibacterials, appropriate supportive therapy, covering management of severe sepsis and septic shock, respiratory failure, as well as management of any decompensated underlying disease, may be critical to improving outcomes in elderly patients with CAP. Immunization with pneumococcal and influenza vaccines has also been demonstrated to be beneficial in numerous large studies. There is good evidence that implementation of guidelines leads to improvement in clinical outcomes in elderly patients with CAP, including a reduction in mortality. Protocols should address a comprehensive set of elements in the process of care and should periodically be evaluated to measure their effects on clinically relevant outcomes. Assessment of functional clinical outcome variables, in addition to survival, is strongly recommended for this population.

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

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

Pneumonia estafilocócica adquirida na comunidade

OBJETIVO: A pneumonia estafilocócica geralmente apresenta uma elevada taxa de morbidade e mortalidade. Normalmente ocorre em infecções por influenza (via aerógena) ou durante episódios de bacteremia (via hematogênica). MÉTODOS: Um estudo retrospectivo e descritivo foi realizado com os pacientes que foram admitidos em nosso hospital entre janeiro de 1992 e dezembro de 2003 com diagnóstico de pneumonia adquirida na comunidade causada por Staphylococcus aureus. Todos eles eram maiores de 14 anos e não usuários de drogas endovenosas. RESULTADOS: De um total de 332 casos de pneumonia adquirida na comunidade, foram encontrados 24 pacientes (7,3%) com pneumonia estafilocócica. A idade mínima e máxima eram de, respectivamente, 14 anos e 89 anos. Quinze pacientes eram homens e nove eram mulheres. Doze pacientes preenchiam critérios para pneumonia grave. O radiograma de tórax evidenciou consolidação unilateral em 14 casos, bilateral em 10, derrame pleural em 15, rápida progressão radiológica das lesões pulmonares em 14, presença de cavitação em 6 e pneumotórax em 1 paciente. A maioria dos pacientes apresentou co-morbidades e diabetes mellitus foi a mais freqüente. Doze pacientes apresentaram complicações como empiema e choque séptico. Houve quatro óbitos, o que representou 16,6% da amostra. CONCLUSÕES: A apresentação clínica da pneumonia causada por S. aureus é similar à apresentação das pneumonias originadas por outros agentes etiológicos. Os achados radiológicos, os dados epidemiológicos e os fatores de risco fornecem importantes indícios para o diagnóstico. Estes fatores são importantes para uma suspeição clínica, já que o S. aureus normalmente não é incluído nos tratamentos empíricos.

Community-acquired Legionella pneumonia: new insights from the German competence network for community acquired pneumonia

BACKGROUND

The Competence Network for Community Acquired Pneumonia (CAPNETZ) offers a unique opportunity to study the epidemiology of legionellosis throughout Germany, applying sophisticated diagnostic tools.

METHODS

The incidence, clinical characteristics, and outcome of Legionella pneumonia in 2503 adult patients with community-acquired pneumonia, participating in the German Multicenter Study of the CAPNETZ, were studied.

RESULTS

Legionella pneumonia was diagnosed in 94 patients (3.8%), thus identifying Legionella species as one of the most common pathogens to cause community-acquired pneumonia. It was equally common among ambulatory and hospitalized patients (3.7% and 3.8%, respectively). The predominant species causing community-acquired pneumonia was Legionella pneumophila; however, 10% of cases were caused by other species not detectable by the urinary antigen test. Patients whose disease was diagnosed by urinary antigen testing experienced a more severe clinical course. Compared with hospitalized patients, ambulatory patients with Legionella pneumonia showed an equal sex distribution, were younger, had fewer comorbidities, fewer cases of discordant initial antimicrobial treatment, and a milder clinical course without fatalities. Thirty percent of patients with Legionella pneumonia received discordant initial antimicrobial treatment without increased mortality.

CONCLUSIONS

Legionella is a leading cause of community-acquired pneumonia in Germany. It needs to be considered equally in hospitalized and ambulatory patients. A positive result of a urine antigen test is associated with a more severe clinical course and leads to a potentially relevant underrecognition of species other than L. pneumophila. Legionella pneumonia in outpatients differs significantly from that in hospitalized patients in terms of clinical presentation and outcome. There was an unacceptably high rate of discordant initial antimicrobial treatment.

Increasing hospital admissions for pneumonia, England

This rise in recorded incidence from 2001 to 2005 was particularly marked among the elderly.

Pneumonia is an important cause of illness and death in England. To describe trends in pneumonia hospitalizations, we extracted information on all episodes of pneumonia that occurred from April 1997 through March 2005 recorded in the Hospital Episode Statistics (HES) database by searching for International Classification of Diseases 10th revision codes J12–J18 in any diagnostic field. The age-standardized incidence of hospitalization with a primary diagnosis of pneumonia increased by 34% from 1.48 to 1.98 per 1,000 population between 1997–98 and 2004–05. The increase was more marked in older adults, in whom the mortality rate was also highest. The proportion of patients with recorded coexisting conditions (defined by using the Charlson Comorbidity Index score) increased over the study period. The rise in pneumonia hospital admissions was not fully explained by demographic change or increasing coexisting conditions. It may be attributable to other population factors, changes in HES coding, changes to health service organization, other biologic phenomenon, or a combination of these effects.

A 30-month experience of thoracic empyema in a tertiary hospital: emphasis on differing bacteriology and outcome between the medical intensive care unit (MICU) and medical ward

OBJECTIVES

To analyze the causative pathogens and outcomes of patients with thoracic empyema admitted to the medical intensive care unit (MICU) and medical ward.

METHODS

We prospectively studied the empyemic patients in the MICU and retrospectively analyzed the medical records of empyemic patients in the medical ward treated in a tertiary university hospital from April 2001 to September 2003.

RESULTS

During this period, 116 patients in the medical ward and 78 patients in MICU had complicated parapneumonic effusions or empyemas. Effusion cultures were positive in 164 patients (85%); a total of 147 and 78 microorganisms were isolated from the 106 medical ward patients and 58 MICU patients, respectively. No matter whether medical ward or MICU patients, aerobic gram-negative organisms were the most common bacteria in positive-culture effusions (110, 67%). Klebsiella pneumoniae (14, 24%) was the predominant pathogen among the MICU patients, and Streptococcus spp. (28, 26%) was the main pathogen among the medical ward patients. Compared with these positive-culture empyemic patients in the medical ward, MICU patients had a significantly higher percentage of aerobic gram-negative organism infections (P = 0.034) and a higher infection-related mortality rate (P = 0.01).

CONCLUSION

The mortality and predominant pathogens in patients with complicated parapneumonic effusions or thoracic empyemas in the medical ward and MICU were different. The increasing gram-negative pathogens in empyemas have become an urgent problem.

Additive effect of pneumococcal vaccine and influenza vaccine on acute exacerbation in patients with chronic lung disease

To determine the clinical efficacy of combined vaccination with 23-valent pneumococcal vaccine (PV) and influenza vaccine (IV) against pneumonia and acute exacerbation of chronic lung diseases (CLD), we conducted an open-label, randomized, controlled study among 167 adults with CLD over a 2-year period. Subjects were randomly assigned to a PV+IV group (n=87) or an IV group (n=80). The number of patients with CLD experiencing infectious acute exacerbation (P=0.022), but not pneumonia (P=0.284), was significantly lower in the PV+IV group compared with the IV group. When these subjects were divided into subgroups, an additive effect of PV with IV in preventing infectious acute exacerbation was significant only in patients with chronic obstructive pulmonary diseases (P=0.037). In patients with CLD, the Kaplan-Meier survival curves demonstrated a significant difference for infectious acute exacerbation (P=0.016) between the two groups. An additive effect of PV with IV on infectious acute exacerbation was found during the first year after vaccination (P=0.019), but not during the second year (P=0.342), and was associated with serotype-specific immune response in sera of these patients who used PV during the same period.

Exposure-dependent effects of ethanol on the innate immune system

Extensive evidence indicates that ethanol (alcohol) has immunomodulatory properties. Many of its effects on innate immune response are dose dependent, with acute or moderate use associated with attenuated inflammatory responses, and heavy ethanol consumption linked with augmentation of inflammation. Ethanol may modify innate immunity via functional alterations of the cells of the innate immune system. Mounting evidence indicates that ethanol can diversely affect antigen recognition and intracellular signaling events, which include activation of mitogen activated protein kinases, and NFkappaB, mediated by Toll-like receptors, leading to altered inflammatory responses. The mechanism(s) underlying these changes may involve dose-dependent effects of ethanol on the fluidity of cell membrane, resulting in interference with the timely assembly or disassembly of lipid rafts. Ethanol could also modify cell activation by specific interactions with cell membrane molecules.

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.

Prior outpatient antibiotic use as predictor for microbial aetiology of community-acquired pneumonia: hospital-based study

OBJECTIVE

The causative micro-organism in community-acquired pneumonia (CAP) is often difficult to predict. Different studies have examined chronic morbidity and clinical symptoms as predictors for microbial aetiology of pneumonia. The aim of our study was to assess whether prior outpatient antimicrobial treatment is predictive for determining the microbial aetiology of CAP.

METHODS

This was a hospital-based prospective observational study including all patients admitted with CAP between 1 October 2004 and 1 August 2006. Microbial investigations included sputum, blood culture, sputum PCR, antigen testing and serology. Exposure to antimicrobial drugs prior to hospital admission was ascertained through community pharmacy dispensing records. Multivariate logistic regression analysis was conducted to assess whether prior outpatient antimicrobial treatment is a predictor of microbial aetiology. Patient demographics, co-morbidities and pneumonia severity were considered to be other potential predictors.

RESULTS

Overall, 201 patients were included in the study. The microbial aetiology was determined in 64% of the patients. The five most prevalent pathogens were Streptococcus pneumoniae, Heamophilus influenzae, Legionella spp., Mycoplasma pneumoniae and Influenza virus A+B. Forty-seven of the patients (23%) had received initial antimicrobial treatment as outpatients. Multivariate analyses revealed that initial outpatient beta-lactam treatment was associated with a threefold increased chance of finding atypical pathogens and a threefold decreased probability of pneumococcal infection; the corresponding odds ratios were 3.51 (95% CI 1.25-9.99) and 0.30 (95% CI 0.10-0.90), respectively. Patients who received macrolides prior to hospitalisation had an increased probability of viral pneumonia.

CONCLUSION

Prior outpatient antimicrobial therapy has a predictive value in the diagnostic workup aimed at identifying the causative pathogen and planning corresponding antimicrobial treatment in patients hospitalised for pneumonia.

Usefulness of C-reactive protein in monitoring the severe community-acquired pneumonia clinical course

BACKGROUND

The aim of the present study was to evaluate the C-reactive protein level, the body temperature and the white cell count in patients after prescription of antibiotics in order to describe the clinical resolution of severe community-acquired pneumonia.

METHODS

A cohort of 53 consecutive patients with severe community-acquired pneumonia was studied. The C-reactive protein levels, body temperature and white cell count were monitored daily.

RESULTS

By day 3 a C-reactive protein level 0.5 times the initial level was a marker of poor outcome (sensitivity, 0.91; specificity, 0.59). Patients were divided according to their C-reactive protein patterns of response to antibiotics, into fast response, slow response, nonresponse, and biphasic response. About 96% of patients with a C-reactive protein pattern of fast response and 74% of patients with a slow response pattern survived, whereas those patients with the patterns of nonresponse and of biphasic response had a mortality rate of 100% and 33%, respectively (P < 0.001). On day 3 of antibiotic therapy, a decrease in C-reactive protein levels by 0.31 or more from the previous day's level was a marker of good prognosis (sensitivity, 0.75; specificity, 0.85).

CONCLUSION

Daily C-reactive protein measurement after antibiotic prescription is useful in identification, as early as day 3, of severe community-acquired pneumonia patients with poor outcome. The identification of the C-reactive protein pattern of response to antibiotic therapy was useful in the recognition of the individual clinical course, either improving or worsening, as well as the rate of improvement, in patients with severe community-acquired pneumonia.

Medical microbiology: laboratory diagnosis of invasive pneumococcal disease

The laboratory diagnosis of invasive pneumococcal disease (IPD) continues to rely on culture-based methods that have been used for many decades. The most significant recent developments have occurred with antigen detection assays, whereas the role of nucleic acid amplification tests has yet to be fully clarified. Despite developments in laboratory diagnostics, a microbiological diagnosis is still not made in most cases of IPD, particularly for pneumococcal pneumonia. The limitations of existing diagnostic tests impact the ability to obtain accurate IPD burden data and to assess the effectiveness of control measures, such as vaccination, in addition to the ability to diagnose IPD in individual patients. There is an urgent need for improved diagnostic tests for pneumococcal disease--especially tests that are suitable for use in underresourced countries.

Influence of bacterial resistances on the efficiency of antibiotic treatments for community-acquired pneumonia

The objective of this paper is to perform a cost-effectiveness analysis of the oral antibiotics used in Spain for the ambulatory treatment of community-acquired pneumonia. Our analysis takes into account the influence of bacterial resistances on the cost-effectiveness ratio of antibiotic alternatives from the viewpoint of the public insurer. A deterministic decision analysis model is used to simulate the impact of treatment alternatives on both patients' health and resource consumption. Amoxicillin 1 g may be the most efficient therapy for treating typical pneumonia, as long as the physician is able to discriminate clinically the aetiology of the process with a high degree of reliability. However, for those pathological pictures in which the aetiology cannot be discriminated clinically, and for those in which the consequences of incorrect diagnosis are serious according to clinical criteria, moxifloxacin is the most effective and efficient option.

Human bocavirus: clinical significance and implications

PURPOSE OF REVIEW

Human bocavirus (HBoV), a parvovirus, was discovered in 2005 with the use of nonspecific genome amplification techniques. Since its discovery, HBoV has been identified worldwide. This review will focus on the epidemiology and clinical features associated with HBoV infection.

RECENT FINDINGS

Initial studies demonstrated the presence of HBoV DNA in respiratory specimens of individuals with respiratory tract disease. Data from some studies suggest that HBoV may be the etiological agent responsible for respiratory tract disease, particularly in young children. HBoV, however, is frequently detected in the presence of other common respiratory viruses. HBoV is not confined to the respiratory tract as evidence of the virus has been detected in serum and stool, the significance of which remains unclear. Presence of the virus in respiratory secretions, serum and stool suggests that this virus may cause systemic illness.

SUMMARY

HBoV is an emerging human parvovirus. The full spectrum of disease associated with HBoV remains to be defined.

Sporadic community-acquired Legionnaires' disease in France: a 2-year national matched case-control study

Legionnaires' disease (LD) is an aetiology of community-acquired bacterial pneumonia in adults, with a high case-fatality ratio (CFR). We conducted a matched case-control study to identify risk factors for sporadic, community-acquired LD. Cases of sporadic, community-acquired and biologically confirmed LD, in metropolitan France from 1 September 2002 to 31 September 2004, were matched with a control subject according to age, sex, underlying illness and location of residence within 5 km. We performed a conditional logistic regression on various host-related factors and exposures. Analysis was done on 546 matched pairs. The CFR was 3.5%. Age ranged from 18-93 years (mean 57 years), with a 3.6 male:female sex ratio. Cases were more likely to have smoked with the documentation of a dose-effect relation, to have travelled with a stay in a hotel (OR 6.1, 95% CI 2.6-14.2), or to have used a wash-hand basin for personal hygiene (OR 3.5, 95% CI 1.6-7.7) than controls. Tobacco and travel have been previously described as risk factors for LD, but this is the first time that such a dose-effect for tobacco has been documented among sporadic cases. These findings will provide helpful knowledge about LD and help practitioners in identifying patients at high risk.