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

Infection in the elderly

Many functional, demographic, and immunologic changes associated with aging are responsible for increasing the incidence and severity of infectious diseases in the elderly. Management is complicated by age-related organ system changes. Because many of the elderly are on multiple medications for underlying illnesses, antimicrobial therapy needs to be chosen keeping drug interactions and adverse events in mind. Common infections seen in the elderly are infections of skin and soft tissue, urinary tract, respiratory tract, and gastrointestinal tract. Organized and well-funded programs to address infectious disease issues in the elderly are the only way to improve care.

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.

Community-Acquired Pneumonia—Back to Basics

Lower respiratory tract infections are among the most common infectious diseases worldwide and are caused by the inflammation and consolidation of lung tissue due to an infectious agent.¹ The clinical criteria for the diagnosis include chest pain, cough, auscultatory findings such as rales or evidence of pulmonary consolidation, fever, or leukocytosis.

Epidemiology and clinical outcomes of community-acquired pneumonia in adult patients in Asian countries: a prospective study by the Asian network for surveillance of resistant pathogens

Appropriate antimicrobial treatment of community-acquired pneumonia (CAP) should be based on the distribution of aetiological pathogens, antimicrobial resistance of major pathogens, clinical characteristics and outcomes. We performed a prospective observational study of 955 cases of adult CAP in 14 hospitals in eight Asian countries. Microbiological evaluation to determine etiological pathogens as well as clinical evaluation was performed. Bronchopulmonary disease (29.9%) was the most frequent underlying disease, followed by cardiovascular diseases (19.9%), malignancy (11.7%) and neurological disorder (8.2%). Streptococcus pneumoniae (29.2%) was the most common isolate, followed by Klebsiella pneumoniae (15.4%) and Haemophilus influenzae (15.1%). Serological tests were positive for Mycoplasma pneumoniae (11.0%) and Chlamydia pneumoniae (13.4%). Only 1.1% was positive for Legionella pneumophila by urinary antigen test. Of the pneumococcal isolates, 56.1% were resistant to erythromycin and 52.6% were not susceptible to penicillin. Seventeen percent of CAP had mixed infection, especially S. pneumoniae with C. pneumoniae. The overall mortality rate was 7.3%, and nursing home residence, mechanical ventilation, malignancy, cardiovascular diseases, respiratory rate > 30/min and hyponatraemia were significant independent risk factors for mortality by multivariate analysis (P < 0.05). The current data provide relevant information about pathogen distribution and antimicrobial resistance of major pathogens of CAP as well as clinical outcomes of illness in Asian countries.

Effects of ethanol on cytokine production after surgery in a murine model of gram-negative pneumonia

BACKGROUND

Both alcohol abuse and surgery have been shown to impair immune function. The frequency of postoperative infectious complications is 2- to 5-fold increased in long-term alcoholic patients, leading to prolonged hospital stay. Following surgery, an increase in interleukin (IL)-6 has been shown to be associated with increased tissue injury and interleukin 1-(IL-10) is known to represent an anti-inflammatory signal. The purpose of this study was to test the hypothesis that several days of excess alcohol consumption results in more pronounced immunosuppression. We assume that alcoholic animals show increased levels of IL-10 in response to infection and increased IL-6 due to a more pronounced lung pathology.

METHODS

Thirty-two female Balb/c mice were pretreated with ethanol (EtOH) at a dose of (3.8 mg/g body weight) or saline (NaCl) for 8 days. At day 8 of the experiment all mice underwent a median laparotomy. Two days postsurgery mice were either applicated 10(4) CFU Klebsiella pneumoniae or received sham-infection with saline. A total number of 4 groups (EtOH/K. pneumoniae; NaCl/K. pneumoniae; EtOH/Sham-infection, NaCl/Sham-infection) was investigated and a clinical score evaluated. Twenty-four hours later mice were killed; lung, spleen, and liver were excised for protein isolation and histological assessment. IL-6 and IL-10 levels were detected by ELISA.

RESULTS

Alcohol-exposed mice exhibited a worsened clinical appearance. The histological assessment demonstrated a distinct deterioration of the pulmonary structure in alcohol-treated animals. In the lung, IL-6 and IL-10 was significantly increased in alcohol-exposed infected mice compared to saline-treated infected mice. The clinical score correlated significantly with IL-6 (r = 0.71; p < 0.01) and IL-10 levels (r = 0.64; p < 0.01) in the lung.

CONCLUSIONS

Ethanol treatment in this surgical model led to a more severe pulmonary infection with K. pneumoniae which was associated with more tissue destruction and increased levels of IL-6 and IL-10 and a worsened clinical score.

Bacterial community-acquired pneumonia in older patients

Pneumonia in the elderly remains a major source of morbidity and mortality in an age group that is growing in numbers. It remains unclear whether the propensity of older adults to develop community-acquired pneumonia represents an aging of host defenses, secondary effects of comorbid disease, or both. The signs and symptoms of pneumonia in the elderly are more subtle than in younger populations, which may lead to a delay in diagnosis. Although therapy for community-acquired pneumonia in the elderly is the same as for younger populations, mortality is higher, leading to an important role for prevention.

Community-acquired pneumonia: aetiologic changes in a limited geographic area. An 11-year prospective study

The aim of this study is to describe the changes in the aetiology of hospitalised patients with community-acquired pneumonia (CAP) during an 11-year observational period in a limited geographic area. Eight hundred and one (801) adult patients with CAP hospitalised were included. The patients were divided into three groups according to the time of presentation. Comprehensive microbiological laboratory tests were performed and differences in aetiology were analysed. In 228 patients (31%), a pathogen was detected, with Coxiella burnetii being the most common (20.1%). Significant variations in the prevalence of Chlamydophila pneumoniae were found between groups but not in other pathogens. In conclusion, long-term epidemiological studies may contribute to the knowledge of actual CAP aetiology.

Clinical features and complete genome characterization of a distinct human rhinovirus (HRV) genetic cluster, probably representing a previously undetected HRV species, HRV-C, associated with acute respiratory illness in children

Although human rhinoviruses (HRVs) are common causes of respiratory illness, their molecular epidemiology has been poorly investigated. Despite the recent findings of new HRV genotypes, their clinical disease spectrum and phylogenetic positions were not fully understood. In this study, 203 prospectively collected nasopharyngeal aspirates (NPAs), negative for common respiratory viruses (83 were human bocavirus [HBoV] positive and 120 HBoV negative), from hospitalized children during a 1-year period were subjected to reverse transcription-PCR for HRV. HRV was detected in 14 NPAs positive and 12 NPAs negative for HBoV. Upon VP4 gene analysis, 5 of these 26 HRV strains were found to belong to HRV-A while 21 belonged to a genetic clade probably representing a previously undetected HRV species, HRV-C, that is phylogenetically distinct from the two known HRV species, HRV-A and HRV-B. The VP4 sequences of these HRV-C strains were closely related to the newly identified HRV strains from the United States and Australia. Febrile wheeze or asthma was the most common presentation (76%) of HRV-C infection, which peaked in fall and winter. Complete genome sequencing of three HRV-C strains revealed that HRV-C represents an additional HRV species, with features distinct from HRV-A and HRV-B. Analysis of VP1 of HRV-C revealed major deletions in regions important for neutralization in other HRVs, which may be signs of a distinct species, while within-clade amino acid variation in potentially antigenic regions may indicate the existence of different serotypes among HRV-C strains. A newly identified HRV species, HRV-C, is circulating worldwide and is an important cause of febrile wheeze and asthmatic exacerbations in children requiring hospitalization.

Infections in Diabetes Mellitus and Hyperglycemia

Infections in diabetes mellitus are relatively more common and serious. Diabetic patients run the risk of acute metabolic decompensation during infections, and conversely patients with metabolic decompensation are at higher risk of certain invasive infections. Tight glycemic control is of paramount importance during acute infected or high stress state. Infections in diabetic patients result in extended hospital stays and additional financial burden. Given the risks of not alleviating the metabolic dysregulation and the benefits of decent glycemic control, it is necessary that besides antimicrobial therapy, equal emphasis be placed on intensified glycemic control.

Clinical and molecular epidemiology of human bocavirus in respiratory and fecal samples from children in Hong Kong

Background. Human bocavirus (HBoV) is a recently discovered parvovirus associated with respiratory tract infections in children. We conducted the first systematic prospective clinical and molecular study using nasopharyngeal aspirates (NPAs) and fecal samples.

Methods. NPAs negative for influenza virus, parainfluenza virus, respiratory syncytial virus, adenovirus, and coronavirus and fecal samples from patients with acute gastroenteritis were included. On the basis of results from a pilot study using 400 NPAs from all age groups, a prospective 12-month study was conducted to detect HBoV in 1200 NPAs and 1435 fecal samples from patients <18 years old by polymerase chain reaction. The complete genome sequences of HBoVs from 12 NPAs and 12 fecal samples were determined.

Results. Of the 400 NPAs collected in the pilot study, 20 (5.0%) were found to contain HBoV, all from children <5 years old. In the subsequent prospective study of pediatric patients, HBoV was detected in 83 (6.9%) of 1200 NPAs. Upper and lower respiratory tract infections were equally common. HBoV was detected in 30 (2.1%) of 1435 fecal samples. Fever and watery diarrhea were the most common symptoms. The seasonality of HBoV in NPAs and fecal samples was similar. Codetection with other pathogens occurred in 33% and 56% of NPAs and fecal samples, respectively, from patients with HBoV infection. Genomes of HBoVs from NPAs and fecal samples displayed minimal sequence variations.

Conclusions. HBoV was detected in fecal specimens in children with acute gastroenteritis. A single lineage of HBoV was associated with both respiratory tract and enteric infections.

Newly discovered respiratory viruses: significance and implications

With the recent advances in molecular biology and the ability to amplify viral genomes in a non-sequence-dependent manner, several previously unidentified human respiratory viruses have been discovered. There are accumulating data that some of these new pathogens are responsible for a substantial proportion of respiratory tract diseases, particularly in children. This review will focus on several of these newly identified pathogens for which there are clinical data implicating a role of these viruses in respiratory tract disease specifically, human metapneumovirus, human coronaviruses NL63 and HKU1, and the human bocavirus. Antivirals and effective vaccines for these new agents may decrease the burden of respiratory tract diseases.

Coxiella burnetiiinfection in C57BL/6 mice aged 1 or 14 months

The objective of this study was to investigate the effects of age on infection with Coxiella burnetii, the agent of Q fever. Bacterial burden and granuloma number were increased in the spleens of 14-month-old as compared with 1-month-old mice. This increase was not the result of an anti-inflammatory macrophage response, because inflammatory and anti-inflammatory cytokines were induced in macrophages from young mice but were repressed in mature mice. In addition, macrophage microbicidal competence was similar in mature and young mice. These results suggest the importance of individual host factors in the pathophysiology of an infectious disease such as Q fever.

Characteristics of community-acquired pneumonia in patients with chronic obstructive pulmonary disease

STUDY OBJECTIVES

Community-acquired pneumonia is a frequent event in the course of chronic obstructive pulmonary disease (COPD). The aim of the present study was to provide information on clinical and microbiological characteristics and outcome of community-acquired pneumonia in these patients, in a comparative study with the non-COPD population.

DESIGN

Prospective study of cases.

SETTING

A university hospital in Lleida, Spain.

PATIENTS

During a 6 year-period, we prospectively studied the clinical and radiological manifestations, microbiological data and outcome of all patients with community-acquired pneumonia. A comparative analysis of characteristics of pneumonia between 132 patients with a definitive diagnosis of COPD and 575 patients who did not have this underlying disease was performed.

MEASUREMENTS AND RESULTS

COPD was associated with an older and predominantly male population. These patients frequently had concomitant comorbidities such as diabetes mellitus or chronic heart failure. Clinical presentation was more severe, manifested by septic shock, tachypnea, lower values of pH, pO(2) and oxygen saturation, and greater values of pCO(2). Purulent expectoration was also more frequent in this subset of patients. Admission was usually required for patients with COPD, and length of hospitalization was significantly increased; however, difference in the mortality rate was not observed. Although the spectrum of responsible microorganisms was very similar, the incidence of Pseudomonas aeruginosa and other Gram-negative bacilli was increased in COPD, particularly among patients with advanced situation and/or oral corticosteroid treatment.

CONCLUSIONS

Community-acquired pneumonia in patients with COPD was associated with epidemiological and clinical particularities mainly related to the underlying disease but showed only minor differences in outcome parameters. Gram-negative bacilli and P. aeruginosa are potential pathogens that need to be considered.

Risk factors and outcomes of influenza A (H3N2) pneumonia in an area where avian influenza (H5N1) is endemic

We conducted a cohort study to identify the risks and outcomes of influenza A (H3N2) pneumonia. Of the 145 patients studied, 10 (7%) had influenza A pneumonia. Logistic regression identified multiple comorbidities (P<.001) and diarrhea at the initial presentation (P=.001) as associated risks. Infection with influenza A (P=.01) and receipt of inadequate antimicrobial therapy (P=.005) were predictors of mortality.

Differential effects of ethanol on IFN-gamma- and TNF-alpha-producing splenic T lymphocytes in a murine model of gram-negative pneumonia

The incidence of bacterial pneumonia is increased in alcoholic patients. Alcohol consumption has been shown to impair cytokine production. Tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) are critical for host defense against Klebsiella pneumoniae (K. pneumoniae). In order to examine the influence of alcohol on the immune response to infection, we investigated the frequency of TNF-alpha and IFN-gamma produced by splenic T-lymphocytes in a murine model of gram-negative pneumonia initiated after 8 days of alcohol treatment. Thirty-two Balb/c mice were pretreated with ethanol (3 mg/g body weight) or saline intraperitoneally over 8 days. On day 7 half of each group was administered K. pneumoniae. Mice were sacrificed 24 hours later to excise lungs and liver for histological assessment and spleens for cell isolation. IFN-gamma- and TNF-alpha-producing CD4(+) and CD8(+) lymphocytes were determined by FACS analysis. In mice with Klebsiella infection, the percentages of IFN-gamma-producing CD4(+) (P < 0.01) and CD8(+) (P < 0.01) were significantly decreased, the percentages of TNF-alpha-producing CD4(+) (P = 0.01) and CD8(+) (P < 0.01) T cells were significantly elevated after alcohol treatment compared with mice with saline treatment. The histological assessment showed an aggravation of K. pneumoniae-induced pneumonia in alcohol-treated mice. Alcohol differentially affects IFN-gamma and TNF-alpha production in Klebsiella-infected mice. Both effects obviously led to a weakened immune response as seen by increased histological damage. This suggests a role of T cells in the increased susceptibility of the alcoholic host to nosocomial infection due to inadequate cytokine response.

Etiology of Community-Acquired Pneumonia in Hospitalized Patients in Chile

BACKGROUND AND STUDY OBJECTIVES

The range and relative impact of microbial pathogens, particularly viral pathogens, as a cause of community-acquired pneumonia (CAP) in hospitalized adults has not received much attention. The aim of this study was to determine the microbial etiology of CAP in adults and to identify the risk factors for various specific pathogens.

METHODS

We prospectively studied 176 patients (mean [+/- SD] age, 65.8 +/- 18.5 years) who had hospitalized for CAP to identify the microbial etiology. For each patient, sputum and blood cultures were obtained as well as serology testing for Mycoplasma pneumoniae and Chlamydophila pneumoniae, urinary antigen testing for Legionella pneumophila and Streptococcus pneumoniae, and a nasopharyngeal swab for seven respiratory viruses.

RESULTS

Microbial etiology was determined in 98 patients (55%). S pneumoniae (49 of 98 patients; 50%) and respiratory viruses (32%) were the most frequently isolated pathogen groups. Pneumococcal pneumonia was associated with tobacco smoking of > 10 pack-years (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.2 to 5.4; p = 0.01). Respiratory viruses were isolated more often in fall or winter (28%; p = 0.011), and as an exclusive etiology tended to be isolated in patients >/= 65 years of age (20%; p = 0.07). Viral CAP was associated with antimicrobial therapy prior to hospital admission (OR, 4.5; 95% CI, 1.4 to 14.6).

CONCLUSIONS

S pneumoniae remains the most frequent pathogen in adults with CAP and should be covered with empirical antimicrobial treatment. Viruses were the second most common etiologic agent and should be tested for, especially in fall or winter, both in young and elderly patients who are hospitalized with CAP.

A worldwide perspective of atypical pathogens in community-acquired pneumonia

RATIONALE

Controversy still exists in the international literature regarding the need to use antimicrobials covering atypical pathogens when initially treating hospitalized patients with community-acquired pneumonia (CAP). In different regions of the world, monotherapy with a beta-lactam antimicrobial is common.

OBJECTIVES

We sought to correlate the incidence of CAP due to atypical pathogens in different regions of the world with the proportion of patients treated with an atypical regimen in those same regions. In addition, we sought to compare clinical outcomes of patients with CAP treated with and without atypical coverage.

METHODS

A secondary analysis was performed using two comprehensive international databases. World regions were defined as North America (I), Europe (II), Latin America (III), and Asia and Africa (IV). Time to reach clinical stability, length of hospital stay, and mortality were compared between patients treated with and without atypical coverage.

MEASUREMENTS AND MAIN RESULTS

The incidence of CAP due to atypical pathogens from 4,337 patients was 22, 28, 21, and 20% in regions I-IV, respectively. The proportion of patients treated with atypical coverage from 2,208 patients was 91, 74, 53, and 10% in regions I-IV, respectively. Patients treated with atypical coverage had decreased time to clinical stability (3.7 vs. 3.2 d, p < 0.001), decreased length of stay (7.1 vs. 6.1 d, p < 0.01), decreased total mortality (11.1 vs. 7%, p < 0.01), and decreased CAP-related mortality (6.4 vs. 3.8%, p = 0.05).

CONCLUSIONS

The significant global presence of atypical pathogens and the better outcomes associated with antimicrobial regimens with atypical coverage support empiric therapy for all hospitalized patients with CAP with a regimen that covers atypical pathogens.

The bacteriology of pneumonia diagnosed in Western Australian emergency departments

We used Western Australian emergency department data linked to hospital morbidity, death and microbiology data to describe the bacteriology of pneumonia according to age. The 'atypical' organisms and viruses were not assessed. A total of 6908 patients over a 3-year period were given an emergency department diagnosis of pneumonia, 76.9% were admitted and 6.3% died in hospital. Blood was cultured from 52.9% of patients with 6.4% growing potential pathogens. Streptococcus pneumoniae was the most common organism isolated and accounted for 92% of pathogens in those aged <15 years. Isolation of Enterobacteriaceae species tended to increase with age and accounted for around 25% of isolates from the elderly. Sputum was cultured from 25.3% of patients and bacteria were isolated from 30.3% of samples, commonly Haemophilus influenzae and S. pneumoniae. Isolates from sputum showed no distinct trend across age groups. These patterns question the value of routine blood and sputum cultures and have implications for empiric therapy for the elderly.

Use of a multiplex real-time PCR to study the incidence of human metapneumovirus and human respiratory syncytial virus infections during two winter seasons in a Belgian paediatric hospital

Viruses are an important cause of acute respiratory tract infection (ARTI) in children. This study aimed to develop and evaluate a rapid molecular diagnostic test (duplex real-time PCR) for human respiratory syncytial virus (hRSV) and human metapneumovirus (hMPV), and to determine the frequency of these two viruses as causative agents of ARTI in Belgium. Nasopharyngeal aspirates were collected over two winter and spring seasons (November 2003 to May 2004 and November 2004 to May 2005) from children aged <5 years with ARTI (n = 778). The duplex real-time PCR showed a linear range of 10⁴–10¹⁰ copies/mL for both hMPV and hRSV. Analysis of the stability of the hRSV and hMPV genomes revealed that nasopharyngeal aspirates could be stored at room temperature for up to 1 month without significant loss of detection. hRSV was detected by antigen testing and by real-time PCR; hMPV was detected by real-time PCR only. The hRSV antigen test was less sensitive than PCR, and failed to detect one-third of the hRSV infections. Overall, 54 (6.9%) and 306 (39.3%) of the 778 samples were positive for hMPV and hRSV, respectively. Both viruses infected young infants, but the mean age of infants infected by hRSV was lower than that of infants infected by hMPV (12 months vs. 17 months, respectively).

Community-Acquired Respiratory Complications in the Intensive Care Unit: Pneumonia and Acute Exacerbations of COPD

This chapter will review the two most common lower respiratory tract infections in the intensive care unit (ICU), community-acquired pneumonia (CAP) and acute exacerbations of chronic obstructive pulmonary disease (AECOPD). In addition we will provide an overview of the topics including recommendations for the diagnosis and treatment.

Community-acquired Staphylococcus aureus pneumonia accompanied by rapidly progressive glomerulonephritis and hemophagocytic syndrome

A 59-year-old woman without underlying disease was admitted to a local hospital because of lung abscess, cytopenias and renal failure. 3 days before admission, she was diagnosed as influenza infection and was under antiviral therapy. Blood cultures were positive for methicillin-sensitive Staphylococcus aureus (MSSA). She was transferred to our hospital on the 15th day at the local hospital because the clinical manifestations could not improve even though she was treated with multiple intravenous antibiotics directed against MSSA. Sputum cultures yielded methicillin-resistant S. aureus (MRSA) producing toxic shock syndrome toxin-1 (TSST-1) and serologic test indicated hypercytokinemia. She was diagnosed as rapidly progressive glomerulonephritis and hemophagocytic syndrome associated with staphylococcal infection. The pulmonary lesions, cytopenias and renal dysfunction improved as a result of long-term antimicrobial treatment including vancomycin, hemodialysis, short-term administration of corticosteroid and other supportive cares. She was finally weaned from hemodialysis on the 73rd hospital day. In recent years, the number of cases of S. aureus producing TSST-1 and enterotoxin has been increasing and in cases of staphylococcal infections, close attention should be given to toxin-mediated as well as non-toxin-mediated clinical manifestations.

The role of new therapies for severe community-acquired pneumonia

PURPOSE OF REVIEW

Community-acquired pneumonia (CAP) is associated with significant morbidity and mortality and is the most common cause of death from infectious diseases. CAP patients requiring intensive care unit (ICU) admission carry the highest mortality rates. This paper aims to review the current literature regarding epidemiology, risk factors, severity criteria and reasons for admitting the hospitalized patient to the ICU, and the empiric and specific antibiotic therapeutic regimens employed.

RECENT FINDINGS

Multiple sets of clinical practice guidelines have been published in the past few years addressing the treatment of CAP. The guidelines all agree that CAP patients admitted to the hospital represent a major concern, and appropriate empiric therapy should be instituted to improve clinical outcomes.

SUMMARY

The cost, morbidity and mortality of CAP patients requiring ICU admission remain unacceptably high. These are heterogeneous groups of patients, so it is important to use risk-stratification based on clinical parameters and prediction tools. Appropriate antibiotic therapy is an important component in the management of both groups of patients. In particular, it is essential to administer an appropriate antimicrobial agent from the initiation of therapy, so that the risks of treatment failure and the morbidity of CAP may be minimized.

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

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

[Managing lower respiratory tract infections in immunocompetent patients. Definitions, epidemiology, and diagnostic features]

Les infections respiratoires basses sont une des principales cause de mortalité dans le monde et les pneumopathies représentent en France la première cause de décès d'origine infectieuse. Trois entités nosologiques distinctes sont habituellement isolées en fonction de la localisation infectieuse : la bronchite aiguë, la pneumopathie et la bronchopneumopathie (atteignant les bronches et le parenchyme pulmonaire). En cas d'infections de l'arbre bronchique dans le cadre d'une bronchopathie chronique on parle de décompensation infectieuse de la maladie bronchique. Les deux principales difficultés diagnostiques de ces infections sont de déterminer la présence d'une participation alvéolaire au processus infectieux et de définir l'agent (ou les agents) pathogènes. Ces deux éléments vont conditionner la prise en charge thérapeutique. En dehors de l'examen physique, indispensable dans ce contexte, seule la radiographie thoracique pourra, en cas de persistance d'un doute, permettre de confirmer la présence d'une participation alvéolaire. Le diagnostic microbiologique pose la question de sa nécessité systématique et celui de sa valeur. Il n'est pas indispensable de réaliser un diagnostic microbiologique de certitude dans tous les cas. La décision de documentation doit répondre à deux impératifs : faisabilité et valeur diagnostique. La valeur d'un prélèvement dépend de son aptitude à mettre en évidence l'agent pathogène et dans certains cas de la possibilité d'en déterminer le profil de sensibilité (qui reste une indication majeure à la réalisation de ces prélèvements).

Comment évaluer, orienter et suivre un patient ayant une pneumonie aiguë communautaire ? Une exacerbation de bronchopneumopathie chronique obstructive ?

L'objectif de cette revue est de présenter une analyse bibliographique de la littérature de ces cinq dernières années concernant les pneumonies aiguës communautaires (PAC) et les exacerbations aiguës de bronchopneumopathies chroniques obstructives (EABPCO). La PAC et l'EABPCO sont des pathologies fréquentes grevées d'une mortalité et/ou morbidité encore élevée de nos jours. La connaissance des facteurs de risque d'évolution compliquée et l'identification des signes de gravité souvent liés au risque de mortalité permettent d'orienter le patient pour un traitement ambulatoire, en hospitalisation conventionnelle ou en secteur de réanimation ; des règles prédictives ont été établies dans ce sens. La littérature concernant les critères de sortie d'hospitalisation et le suivi des patients est plus pauvre.

Assessment of analysis of urinary pneumococcal antigen by immunochromatography for etiologic diagnosis of community-acquired pneumonia in adults

The limitations of conventional microbiologic methods (CMM) for etiologic diagnosis of community pneumococcal pneumonia have made faster diagnostic techniques necessary. Our aim was to evaluate the usefulness of the immunochromatography (ICT) technique for detecting urinary Streptococcus pneumoniae antigen in the etiologic diagnosis of community-acquired pneumonias (CAP). This was a prospective study on in-patients with CAP in a tertiary hospital conducted from October 2000 to March 2004. Apart from using CMM to reach an etiologic diagnosis, we determined pneumococcal antigen in concentrated urine by ICT. We also determined the urinary pneumococcal antigen (UPA) content in patients from two control groups to calculate the specificity of the technique. One group was comprised of in-patients diagnosed with chronic obstructive pulmonary disease (COPD) or asthma, with respiratory infection, and without pneumonia; the other group included fractures. We studied 959 pneumonia patients and determined UPA content in 911 (95%) of them. We diagnosed the etiology of 253 cases (28%) using CMM; S. pneumoniae was the most common etiologic agent (57 cases). ICT analysis was positive for 279 patients (31%). Using this technique, the percentage of diagnoses of pneumococcal pneumonias increased by 26%, while the overall etiologic diagnosis increased from 28 to 49%. The technique sensitivity was 81%; the specificity oscillated between 80% in CAP with nonpneumococcal etiology and 99% for patients with fractures without infections. Determination of UPA is a rapid, simple analysis with good sensitivity and specificity, which increased the percentage of etiologic diagnoses. Positive UPA may persist in COPD patients with probable pneumococcal colonization or recent pneumococcal infections.

Addictive drugs and their relationship with infectious diseases

The use of drugs of abuse, both recreationally and medicinally, may be related to serious public health concerns. There is a relationship between addictive drugs of abuse such as alcohol and nicotine in cigarette smoke, as well as illegal drugs such as opiates, cocaine and marijuana, and increased susceptibility to infections. The nature and mechanisms of immunomodulation induced by such drugs of abuse are described in this review. The effects of opiates and marijuana, using animal models as well as in vitro studies with immune cells from experimental animals and humans, have shown that immunomodulation induced by these drugs is mainly receptor-mediated, either directly by interaction with specific receptors on immune cells or indirectly by reaction with similar receptors on cells of the nervous system. Similar studies also show that cocaine and nicotine have marked immunomodulatory effects, which are mainly receptor-mediated. Both cocaine, an illegal drug, and nicotine, a widely used legal addictive component of cigarettes, are markedly immunomodulatory and increase susceptibility to infection. The nature and mechanism of immunomodulation induced by alcohol, the most widely used addictive substance of abuse, are similar but immunomodulatory effects, although not receptor-mediated. The many research studies on the effects of these drugs on immunity and increased susceptibility to infectious diseases, including AIDS, are providing a better understanding of the complex interactions between immunity, infections and substance abuse.

Adherence to infectious diseases society of America guidelines for empiric therapy for patients with community-acquired pneumonia in a commercially insured cohort

BACKGROUND

There is little published research addressing how the 2003 Infectious Diseases Society of America (IDSA) guidelines for empiric therapy of community-acquired pneumonia (CAP) are implemented in clinical practice.

OBJECTIVE

This study was designed to describe antibiotic treatment patterns among patients with CAP treated in ambulatory settings in light of the IDSA guidelines.

METHODS

Health insurance claims data from a large managed care organization with -30 million enrollees located in geographically diverse regions of the United States were analyzed. Patients > or =18 years of age with CAP who received a prescription for any antibiotic in an ambulatory setting during 2004 were identified via International Classification of Diseases, Ninth Revision, Clinical Modification codes for diagnosis (481-486). Recent antibiotic use was defined as receipt of any antibiotics <90 days before the date of diagnosis. Antibiotics were identified through National Drug Codes and from outpatient medical claims data with the use of J codes. Individuals were classified, per IDSA guidelines, as previously healthy without recent antibiotic use (group 1); previously healthy with recent antibiotic use (group 2); with comorbidities and without recent antibiotic use (group 3); and with comorbidities and recent antibiotic use (group 4). The guideline adherence was calculated using the number of patients receiving recommended treatment divided by the total number of patients in each group.

RESULTS

Of 34,342 patients identified, 76.5% had no reported comorbidities. Among group-1 patients, 52.0% received the recommended empiric therapy (macrolide or doxycycline). In group-2 patients, 42.5% received the recommended therapy (respiratory quinolone alone or advanced-generation macrolide plus amoxicillin or amoxicillin-clavulanate). A high rate of compliance with recommended empiric therapy (advanced-generation macrolides or respiratory quinolones) was observed in group-3 patients (81.5%). In group-4 patients, 43.4% received the recommended therapy (respiratory quinolone or advanced-generation macrolide plus ss-lactam). Patients whose therapy was adherent with the guidelines had fewer respiratory-infection-related hospital admissions within 30 days after initiation of antibiotic treatment (overall, relative risk = 0.81 [95% CI, 0.71-0.94]).

CONCLUSION

Although these data reflect a period shortly after the 2003 IDSA guidelines were published, they suggest that there is room for improvement with regard to choice of empiric antibiotic therapy among these patients with CAP treated in ambulatory settings.

Determinants of short and long term functional recovery after hospitalization for community-acquired pneumonia in the elderly: role of inflammatory markers

Background

Hospitalization for older patients with community-acquired pneumonia (CAP) is associated with functional decline. Little is know about the relationship between inflammatory markers and determinants of functional status in this population. The aim of the study is to investigate the association between tumor necrosis factor (TNF)-α, C-reactive protein (CRP) and Activities of Daily Living, and to identify risk factors associated with one year mortality or hospital readmission.

Methods

301 consecutive patients hospitalized for CAP (mean age 73.9 ± 5.3 years) in a University affiliated hospital over 18 month period were included. All patients were evaluated on admission to identify baseline demographic, microbiological, cognitive and functional characteristics. Serum levels for TNF-α and CRP were collected at the same time. Reassessment of functional status at discharge, and monthly thereafter till 3 months post discharge was obtained and compared with preadmission level to document loss or recovery of functionality. Outcome was assessed by the composite endpoint of hospital readmission or death from any cause up to one year post hospital discharge.

Results

36% of patients developed functional decline at discharge and 11% had persistent functional impairment at 3 months. Serum TNF-α (odds ratio [OR] 1.12, 95% CI 1.08–1.15; p < 0.001) and the Charlson Index (OR = 1.39, 95% CI 1.14 to 1.71; p = 0.001) but not age, CRP, or cognitive status were independently associated with loss of functionality at the time of hospital discharge. Lack of recovery in functional status at 3 months was associated with impaired cognitive ability and preadmission comorbidities. In Cox regression analysis, persistent functional impairment at 3 months, impaired cognitive function, and the Charlson Index were highly predictive of one year hospital readmission or death.

Conclusion

Serum TNF-α levels can be useful in determining patients at risk for functional impairment following hospitalization from CAP. Old patients with impaired cognitive function and preexisting comorbidities who exhibit delay in functional recovery at 3 months post discharge may be at high risk for hospital readmission and death. With the scarcity of resources, a future risk stratification system based on these findings might be proven helpful to target older patients who are likely to benefit from interventional strategies.

Coronavirus HKU1 and other coronavirus infections in Hong Kong

We have recently described the discovery of a novel coronavirus, coronavirus HKU1 (CoV-HKU1), associated with community-acquired pneumonia. However, the clinical spectrum of disease and the epidemiology of CoV-HKU1 infections in relation to infections with other respiratory viruses are unknown. In this 12-month prospective study, 4,181 nasopharyngeal aspirates from patients with acute respiratory tract infections were subjected to reverse transcription-PCRs specific for CoV-HKU1 and human coronaviruses NL63 (HCoV-NL63), OC43 (HCoV-OC43), and 229E (HCoV-229E). Coronaviruses were detected in 87 (2.1%) patients, with 13 (0.3%) positive for CoV-HKU1, 17 (0.4%) positive for HCoV-NL63, 53 (1.3%) positive for HCoV-OC43, and 4 (0.1%) positive for HCoV-229E. Of the 13 patients with CoV-HKU1 infections, 11 were children and 8 had underlying diseases. Similar to the case for other coronaviruses, upper respiratory infection was the most common presentation of CoV-HKU1 infections, although pneumonia, acute bronchiolitis, and asthmatic exacerbation also occurred. Despite a shorter duration of fever (mean, 1.7 days) and no difference in maximum temperature in children with CoV-HKU1 infections compared to patients with most other respiratory virus infections, a high incidence of febrile seizures (50%) was noted, which was significantly higher than those for HCoV-OC43 (14%), adenovirus (9%), human parainfluenza virus 1 (0%), and respiratory syncytial virus (8%) infections. CoV-HKU1 and HCoV-OC43 infections peaked in winter, although cases of the former also occurred in spring to early summer. This is in contrast to HCoV-NL63 infections, which mainly occurred in early summer and autumn but were absent in winter. Two genotypes of CoV-HKU1 cocirculated during the study period. Continuous studies over a longer period are warranted to ascertain the seasonal variation and relative importance of the different coronaviruses. Similar studies in other countries are required to better determine the epidemiology and genetic diversity of CoV-HKU1.

Macrolide resistance in bacteremic pneumococcal disease: implications for patient management

BACKGROUND

Despite pneumococcal antibiotic resistance rates in excess of 25%, macrolides remain first-line agents for the treatment of community-acquired pneumonia.

METHODS

Prospective, population-based surveillance was conducted to identify cases of pneumococcal bacteremia in Toronto and Peel, Canada, between 2000 and 2004. "Macrolide failures" were defined as cases of bacteremia occurring during outpatient treatment with macrolide antibiotics or within 2 days after treatment. Macrolide susceptibility was determined according to Clinical Laboratory Standards Institute guidelines; common macrolide resistance mechanisms were determined by genotyping.

RESULTS

During the 5 years of surveillance, there were 1696 episodes of pneumococcal bacteremia (8.5 cases/100,000 population/year), of which 60 (3.5%) were failures of outpatient macrolide therapy. Resistant isolates were more common among cases of bacteremia after failure of macrolide therapy (37 [64%] of 58 cases) than among cases of bacteremia after failure of nonmacrolide antibiotics (16 [22%] of 74 cases; P<.001) or cases of bacteremia that occurred without prior antibiotic therapy (193 [12%] of 1569 cases; P<.001). Macrolide failures were significantly more common among cases of pneumococcal bacteremia with isolates exhibiting an erythromycin MIC of 1 microg/mL than among isolates exhibiting MICs < or = 0.25 microg/mL (3 [38%] of 8 cases vs. 21 [1.5%] of 1394 cases of bacteremia; P<.001). Increases in the MIC to 1 microg/mL were not associated with further increases in the likelihood of macrolide failure. Low-level resistance conferred by mefA and high-level resistance conferred by ermB were equally overrepresented among macrolide failures.

CONCLUSIONS

Macrolide resistance contributes to an increased risk of macrolide failure, irrespective of the underlying resistance mechanism or of the degree of elevation in erythromycin MIC.

Epidemiology of human metapneumovirus

Since the discovery of human metapneumovirus (hMPV) in 2001, the virus has been identified worldwide. hMPV is a common respiratory pathogen, particularly in infants and young children. The virus is associated with both upper and lower respiratory tract infections and may be a trigger for asthma. At least two major genotypes of hMPV circulate during community outbreaks. Whether these genotypes represent distinct serotypes remains controversial. The major challenges faced by the medical and scientific communities are the understanding of the pathogenesis of hMPV disease and the development of a safe and effective vaccine to protect against infection and disease caused by this newly recognized respiratory virus.

Statin treatment and reduced risk of pneumonia in patients with diabetes

BACKGROUND

Recent prognostic studies have shown that previous treatment with statins is associated with a better outcome in patients admitted to hospital with pneumonia. Because of an increased risk of pneumonia in patients with diabetes, we assessed the effects of statin use on the occurrence of pneumonia in adult diabetic patients.

METHODS

All patients with a diagnosis of diabetes (types 1 and 2) enlisted in the UK General Practice Research Database between 1 June 1987 and 21 January 2001 were included. A case-control study was performed with cases defined as patients with a first recorded diagnosis of pneumonia. For each case up to four controls were matched by age, sex, practice, and index date. Patients were classified as current users when the index date was between the start and end date of statin treatment. Conditional multiple logistic regression analysis was used to estimate the strength of the association between statin treatment and the occurrence of pneumonia.

RESULTS

Statins were used in 1.1% of 4719 cases and in 2.1% of 15 322 matched controls (crude odds ratio (OR) 0.51, 95% CI 0.37 to 0.68). After adjusting for potential confounders, treatment with statins was associated with a significant reduction in the risk of pneumonia (adjusted OR 0.49, 95% CI 0.35 to 0.69). The association was consistent among relevant subgroups (cardiovascular diseases, pulmonary diseases) and independent of the use of other prescription drugs.

CONCLUSIONS

The use of statins is associated with a considerable reduction in the risk of pneumonia in diabetic patients. In addition to lowering the risk of cardiovascular disease, statins may be useful in preventing respiratory infections.

Detection of Chlamydophila pneumoniae IgG in paired serum samples: comparison of serological techniques in pneumonia cases

Serological diagnosis of Chamydophila pneumoniae is usually undertaken by complement fixation test (CFT) or by microimmunofluorescence (MIF). A number of commercial methods for detecting C. pneumoniae-specific IgG have been developed. The aim of this study was to compare the performance characteristics of six methods for the diagnosis of pneumonia due to C. pneumoniae, including CFT (in house), MIF (Vircell, Spain), and four ELISAs (Medac, Germany; Savyon, Israel; Serion, Germany; and DRG, Germany). ELISA-Medac, ELISA-Savyon, ELISA-DRG and MIF use C. pneumoniae antigens while ELISA-Serion and CFT use Chlamydophila genus-specific antigen. Acute and convalescent samples from 85 pneumonia patients were studied. Using CFT, cases were initially classified as due to Chlamydophila (43 cases); to other agents (23 cases) (influenza A and B, Mycoplasma pneumoniae, respiratory syncytial virus, adenovirus and Legionella pneumophila); or as negative (19 cases). Cases were considered positive if they showed seroconversion, a significant rise in titer or high titer; and were finally classified as positive if they gave a positive result in at least three assays. Sensitivity values ranged from 87% to 97.8%; and specificity from 84.6% to 97.4%. In conclusion, the assays compared appear to be useful tools for the diagnosis of pneumonia due to Chlamydophila.

Human metapneumovirus in adults: a short case series

This study was carried out to further the available information on adult cases of human metapneumovirus (hMPV), a recently described cause of respiratory infection. Among a cohort of 741 symptomatic patients tested since 2003, the virus was diagnosed in six adults using reverse transcriptase polymerase chain reaction. Of the six, two were from the community, two were hospital inpatients with chronic obstructive pulmonary disease and two were immunocompromised patients, both of whom required ventilation and later died. This report discusses the clinical features, epidemiology and diagnosis of hMPV, highlighting that this infection may be associated with death in high-risk adults. For adults presenting with respiratory symptoms and a background of pre-existing respiratory disease or who are immunocompromised, nucleic acid-based techniques are a cost-effective means of making the viral diagnosis in a clinically relevant time frame.

[Pneumonia - pathogen-based or constellation-based therapy?]

Community-acquired pneumonia is one of the most frequent infectious diseases with high morbidity and mortality. Early and sufficient antibiotic treatment is crucial for the prognosis of the patient. The underlying pathogens are mostly unknown at the onset of symptoms. The choice of antibiotic treatment depends on the suspected pathogens, derived from the typical germs and the typical resistances in a certain area. In addition, individual risk factors, such as age, severity of the diseases, comorbidities, and previous antibiotic treatment have a major impact on the probability of dying for an individual patient. These factors must be considered at the beginning of any treatment. Pathogen-based treatment has to be switched to constellation-based treatment.

Haemophilus Influenzae contributes to morbidity but not mortality in severely burned patients

Due to a successful Haemophilus Influenzae (HIF) vaccination program, this pathogen is no longer a major contributor to childhood morbidity and mortality. The effect on adult acquisition of HIF is unknown. The purpose of this study was to determine HIF infection frequency in severely burned patients. In a 62-month period, there were 1486 admissions. Twenty-four of 1,486 (1.6%) burn patients had HIF pneumonia: 16 (1%) within 72 h after injury; 8 (0.5%) patients developed it after the seventh day of hospitalization; 74 of 1,486 (5.0%) burn patients had pneumonia due to other organisms. There was no statistically significant difference between patients with HIF pneumonia and those with other pathogens with respect to age, race, sex, percent total body surface area (TBSA), inhalation injury, ventilator days, intensive care days, sepsis, or mortality. Nineteen percent of patients with HIF were<14 years of age compared to 12% in the other pneumonia group, p<0.01. HIF contributed to both an early and late pneumonia in burn patients. The organism responded to treatment and did not affect mortality.

Impact of alcohol abuse in the etiology and severity of community-acquired pneumonia

BACKGROUND AND STUDY OBJECTIVES

Alcohol consumption is known to affect both systemic and pulmonary immunity, predisposing the patient to pulmonary infections. The aim of this study was to compare the etiology of disease, the antibiotic resistance of Streptococcus pneumoniae, the severity of disease, and the outcome of patients with alcohol abuse to those of nonalcoholic (NA) patients who have been hospitalized for community-acquired pneumonia (CAP).

METHODS

From 1997 to 2001, clinical, microbiological, radiographic, and laboratory data, and follow-up variables of all consecutive patients who had been hospitalized with CAP were recorded. Patients were classified as alcoholic (A) [n = 128] or ex-alcoholic (EA) patients (n = 54) and were compared to NA patients (n = 1,165).

RESULTS

S pneumoniae was found significantly more frequently in all patients with alcohol misuse. As regards the rates of antibiotic resistance, invasive pneumococcal disease, and other microorganisms, no differences were found. The severity criteria for CAP according to the American Thoracic Society were more frequent in A patients, but mortality did not differ significantly. Multivariate analysis showed an independent association between pneumococcal CAP and alcoholism (A patients: odds ratio [OR], 1.6; p = 0.033; EA patients: OR, 2.1; p = 0.016).

CONCLUSIONS

We found an independent association between pneumococcal infection and alcoholism. Current alcohol abuse was associated with severe CAP. No significant differences were found in mortality, antibiotic resistance of S pneumoniae, and other etiologies.

Epidemiology of community- and nursing home-acquired pneumonia in older adults

Pneumococcus remains the most important cause of community-acquired pneumonia in older adults. Alcoholism, bronchial asthma, immunosuppression, lung disease, heart disease, institutionalization and increasing age are important risk factors. There is a reduced prevalence of nonrespiratory symptoms in this age group. Advanced age and comorbidity are important prognostic factors. Influenza and pneumococcal vaccination remain the key factors for prevention.

Method for discovering novel DNA viruses in blood using viral particle selection and shotgun sequencing

Rapid identification of viruses is needed to monitor the blood supply for emerging threats. Here we present a method that meets these criteria and allows for the shotgun sequencing of novel, uncultured DNA viruses directly from human blood. This method employs selection based on the physical properties of viruses combined with sequence-independent amplification and cloning. We show that both single- and double-stranded DNA viruses can be recovered from blood samples using this approach. In addition, we report the discovery of novel anellovirus sequences in the blood of healthy donors. PCR primers designed to amplify these novel anellovirus sequences were then used to verify the presence of these viruses in the general donor population.

Estudio de un brote de infección por Legionella pneumophila

BACKGROUND AND OBJECTIVE

To describe an outbreak of Legionella pneumophila serogroup 1 in Mataró, Catalunya, Spain, in August 2002. The source of the microorganism was a cooling tower.

PATIENTS AND METHOD

Prospective and observational study with analysis of epidemiological, clinical, and microbiological data.

RESULTS

151 patients were affected (62% male), with a mean age of 58.4 years old. Seven patients were classified as Pontiac Fever and 144 suffered from pneumonia. The diagnosis of pneumonia was confirmed in 79% of cases, was considered suspicious in 14% and probable in 7%. Forty per cent of patients were smokers and 53.5% had comorbidities, mainly diabetes mellitus (22%). Chief symptoms were fever (97%), chills and muscular pain (63% respectively), headache (54%) and cough (53%). Pulmonary condensation was the more frequent radiological feature (71%). Normal pulmonary exploration was observed in 38%. Forty-three per cent of cases were severely ill, and 16% of patients belonged to Fine's IV and V class. Antigenuria was the most important test for diagnosis, which confirmed 76% of cases. Legionella spp. was obtained in respiratory secretions of 10 patients. Molecular analysis confirmed clonality between respiratory microorganisms and that obtained in the cooling tower.

CONCLUSION

The outbreak involved an important number of subjects in a short period of time. Antigenuria was the most useful test. However, the isolation of L. pneumophila from patients permitted the prompt identification of microorganism's source in a cooling tower. The low mortality observed probably relates to a rapid diagnosis and its target treatment.

Prior outpatient antibacterial therapy as prognostic factor for mortality in hospitalized pneumonia patients

STUDY OBJECTIVES

To assess whether prior outpatient treatment is associated with outcome in patients hospitalized for community-acquired pneumonia (CAP).

PATIENTS AND METHODS

All patients with a first hospital admission for CAP between 1995 and 2000 were selected. Patients were divided into two groups, one of patients with use of antibacterial agents prior to hospitalization and one of patients treated as inpatient directly. The main outcome measures were duration of hospital stay and in-hospital mortality.

RESULTS

The two patient groups comprised 296 and 794 patients, respectively. The median duration of hospital stay was 10 days and was similar for both groups. In patients with respiratory diseases or heart failure, the median duration of hospital stay was 12 and 14 days, respectively. The overall in-hospital mortality was 7.2% and did not largely differ between both groups. In patients with congestive heart failure, the mortality was 9.8% for controls and 23.3% for patients hospitalized after initial outpatient treatment (adjusted OR 2.78, 95% CI 1.01-7.81).

CONCLUSIONS

Prior outpatient antibacterial therapy is not associated with outcome in hospitalized pneumonia patients. In patients with underlying chronic heart failure, prior outpatient antibiotic is associated with a significant increased mortality.