This is a fairly easy epidemiology question, in adults without other data, Pneumococcus is the 1st.

This is a fairly easy epidemiology question, in adults without other data, Pneumococcus is the [HIDDEN].

A 40-year-old male patient, smoker since he was 18 years old, with no history of interest. He consults for symptoms of 24 hours of evolution of chills, thermometric fever of 39ºC and cough with expectoration. Chest X-ray shows an increased density with alveolar pattern in the LSD and the patient is diagnosed with CAP. What is the most frequent etiological agent and therefore of obligatory coverage when choosing empirical atb treatment?

The incidence and etiology of community-acquired pneumonia in fever outpatients.

The purpose of this study was to analyze the incidence, etiology and clinical characteristics of community-acquired pneumonia (CAP) among outpatients with sore throat and/or cough, and thus to provide theoretical basis for timely and accurate diagnosis and treatment for CAP. We used chest X-rays for fever (a temperature greater than 37.5°C) patients, who were recruited since 2007, presenting with sore throat and/or cough. The patients' age, gender, days of fever, respiratory symptoms (e.g. cough and sputum), peripheral blood count and etiology (pathogens) of CAP were recorded. Of all the 6539 fever outpatients, those aged 10-39 and above 60 years old accounted for 61.0% and 15.6%, respectively. In total, 402 were diagnosed with CAP with an incidence rate of 6.1%. Among them, 38.1% were above 60 years old. The prevalence increased with age. Of the 402 CAP patients, 36.8% (148/402) presented no respiratory symptoms and 30.1% (121/402) had positive etiology. The top three pathogens were Mycoplasma pneumoniae (23.1%), Streptococcus pneumoniae (17.3%) and Haemophilus influenzae (9.1%). Among the 121 etiology-positive patients, 14 cases were mixed infections (at least one atypical pathogen). Nine cases were M. pneumoniae mixed with bacterial/virus infection, and five cases were Chlamydia pneumoniae mixed with other bacteria/mycoplasma infection. We found that fever outpatients have a higher prevalence of CAP, which increases with age, i.e. older people are more susceptible to CAP. S. pneumoniae and H. influenzae are common pathogens in CAP; however, atypical pathogens, especially M. pneumoniae, remain the most common pathogens in CAP.

[Treatment of community-acquired pneumonia by pristinamycin (Pyostacine 500). Results of a non comparative open study].

Activity of natural streptogramin (NSG) appears well adapted to pathogens responsible for CAP. The goal of this multicenter pilot study was to bring first data about efficacy of NSG in treatment of CAP. PATIENTS METHOD: Ten days of a NSG (1 gr b.i.d. or t.i.d.) regimen was administered to 46 hospitalized adult patients for CAP defined with fever > 38 degrees C, respiratory symptoms and X-ray opacity. Severely ill patients were excluded. A broncho-pulmonar sample (expectoration or trantracheal aspiration or protected distal sample) was performed in all patients. two patients were excluded because of pulmonary embolism (n = 1) or tuberculosis (n = 1) and 44 patients were analyzed. 50% of them had associated disease, 20% had failure of prior antibiotherapy. At inclusion, mean fever was 39.2 +/- 0.7 degrees C, respiratory rate was 22 +/- 5/mn, PaO2 was 74 +/- 10 mmHg, chest X-ray showed bilateral opacity in 16%, unilateral in 84% and pleural fluid level in 6 cases. Etiological diagnosis was determined in 70% of cases. Streptococcus pneumoniae (n = 14), Haemophilus influenzae (n = 5), Legionella pneumophila (n = 2), Mycoplasma pneumoniae (n = 2) and Chlamydia psittaci (n = 1) were the most frequent isolated pathogens. 40 patients (91%) were cured with NSG and delay to obtain apyrexia was 4.4 +/- 3.9 days. NSG was stopped in 4 patients: 1 clinical and bacteriological failure (Klebsiella pneumoniae), 2 clinical failures (1 pneumococcus with purulent pleurisy, 1 pneumococcus with worsening of respiratory status), 1 patient with resistant H. influenzae strain in spite of favourable clinical evolution. NSG was well tolerated in 86% of patients. these data invite to carry on evaluation of first line therapy of CAP with NSG.

[Community acquired pneumonia. Reliability of the criteria for deciding ambulatory treatment].

To determine whether criteria for not admitting community-acquired pneumonia (CAP) patients diagnosed in the emergency room are appropriate, and to characterize the symptoms, etiology and course of CAP. This one-year prospective, protocol study of immunocompetent CAP patients diagnosed in the emergency room of our hospital enrolled patients not considered to require hospital admission according to the recommendations of the Spanish Society of Respiratory Disease (SEPAR). Medical histories, chest X-rays and blood analysis were obtained for all patients. Blood cultures were analyzed for antibodies against Legionella pneumophila, Mycoplasma pneumoniae, Coxiella burnetii, Chlamydia pneumoniae, Chlamydia psittaci and influenza virus types A and B. The patients received erythromycin for 14 days and were regularly checked by the pulmonologist in the outpatient clinic until signs and symptoms had disappeared. One hundred six patients were enrolled. Mean age was 36 +/- 13 years. Only 3 patients had to be admitted to hospital, after which outcome was good. The main symptoms were fever (106, 100%) and cough (83, 78%). In 46 (43.4%) chest sounds were normal. Microbiologic diagnoses were achieved for 28 (26.4%) and Coxiella burnetii was the agent most often found (19, 17.9%). Outcome was good in all cases, with faster disappearance of symptoms than of radiological signs. The SEPAR criteria for admitting patients with CAP are appropriate. The clinical symptoms of such patients are non specific, a noteworthy finding being that many patients had normal chest sounds. Coxiella burnetii was the most common causative agent. Both clinical and radiological outcomes were excellent.

Community-acquired pneumonia. A prospective outpatient study.

We initiated a prospective study with a group of practitioners to assess the etiology, clinical presentation, and outcome of community-acquired pneumonia in patients diagnosed in the outpatient setting. All patients with signs and symptoms suggestive of pneumonia and an infiltrate on chest X-ray underwent an extensive standard workup and were followed over 4 weeks. Over a 4-year period, 184 patients were eligible, of whom 170 (age range, 15-96 yr; median, 43 yr) were included and analyzed. In 78 (46%), no etiologic agent could be demonstrated. In the remaining 92 patients, 107 etiologic agents were implicated: 43 were due to "pyogenic" bacteria (39 Streptococcus pneumoniae, 3 Haemophilus spp., 1 Streptococcus spp.), 39 were due to "atypical" bacteria (24 Mycoplasma pneumoniae, 9 Chlamydia pneumoniae, 4 Coxiella burnetii, 2 Legionella spp.), and 25 were due to viruses (20 influenza viruses and 5 other respiratory viruses). There were only a few statistically significant clinical differences between the different etiologic categories (higher age and comorbidities in viral or in episodes of undetermined etiology, higher neutrophil counts in "pyogenic" episodes, more frequent bilateral and interstitial infiltrates in viral episodes). There were 2 deaths, both in patients with advanced age (83 and 86 years old), and several comorbidities. Only 14 patients (8.2%) required hospitalization. In 6 patients (3.4%), the pneumonia episode uncovered a local neoplasia. This study shows that most cases of community-acquired pneumonia have a favorable outcome and can be successfully managed in an outpatient setting. Moreover, in the absence of rapid and reliable clinical or laboratory tests to establish a definite etiologic diagnosis at presentation, the spectrum of the etiologic agents suggest that initial antibiotic therapy should cover both S. pneumoniae and atypical bacteria, as well as possible influenza viruses during the epidemic season.

Microbiological etiology in clinically diagnosed community-acquired pneumonia in primary care in Orebro, Sweden.

To study the etiology of clinically diagnosed community-acquired pneumonia (CAP) in antibiotically naive patients attending a primary care center and treated at their homes. A three-year prospective study was carried out, and 177 patients presenting with clinical signs of CAP were included. All patients had chest X-rays after inclusion, and 82 (46%) showed infiltrates. Nasopharyngeal swab culture was performed on all patients, and 51% produced a representative sputum sample. Paired sera were obtained from 176 patients. Among the 82 patients with radiographically proven CAP, Streptococcus pneumoniae was detected in 26 patients (32%), Haemophilus influenzae in 23 (28%), Mycoplasma pneumoniae in 15 (18%), and Chlamydia pneumoniae in four (5%). Serologic evidence of a viral infection was found in 13 patients (16%). Among the 95 patients without infiltrates, S. pneumoniae was found in 21 (22%), H. influenzae in 14 (15%), M. pneumoniae in two (2%), and C. pneumoniae in five (5%). Viral infection was detected in 19 (20%) of these 95 patients. In primary care in Sweden, the initial antibiotic treatment in any patient with pneumonia should be effective against S. pneumonia and H. influenzae. In addition, M. pneumoniae should be targeted during recurrent epidemics. C. pneumoniae, and especially Legionella, seem to be uncommon in primary care.

Clinical, epidemiological, and etiological profile of inpatients with community-acquired pneumonia at a general hospital in the Sumaré microregion of Brazil.

To analyze the clinical, etiological, and epidemiological aspects of community-acquired pneumonia (CAP) in hospitalized individuals. We prospectively studied 66 patients (> 14 years of age) with CAP admitted to the Hospital Estadual Sumaré, located in the Sumaré microregion of Brazil, between October of 2005 and September of 2007. We collected data related to clinical history, physical examination, pneumonia severity index (PSI) scores, and laboratory tests (blood culture; sputum smear microscopy and culture; serology for Chlamydophila pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila; and detection of Legionella sp. and Streptococcus pneumoniae antigens in urine). The mean age of patients was 53 years. Most had a low level of education, and 55.7% presented with at least one comorbidity at the time of hospitalization. The proportion of elderly people vaccinated against influenza was significantly lower among the inpatients than in the general population of the Sumaré microregion (52.6% vs. > 70%). Fever was less common among the elderly patients (p < 0.05). The clinical evolution was associated with the PSI scores but not with age. The etiology was confirmed in 31 cases (50.8%) and was attributed to S. pneumoniae, principally detected by the urinary antigen test, in 21 (34.4%), followed by C. pneumoniae, in 5 (8.2%). The mortality rate was 4.9%, and 80.3% of the patients were classified as cured at discharge. The knowledge of the etiologic profile of CAP at the regional level favors the appropriate choice of empirical treatment, which is particularly relevant in elderly patients and in those with comorbidities. The lack of influenza vaccination in elderly patients is a risk factor for hospitalization due to CAP.

Clinico-pathological study of atypical pathogens in community-acquired pneumonia: a prospective study.

Atypical respiratory pathogens such as Mycoplasma pneumoniae, Legionella species, and Chlamydia pneumoniae are isolated with increasing frequency from community-acquired pneumonia (CAP). This study highlights the importance of organisms responsible for CAP. One hundred consecutive patients with clinically and radiographically diagnosed CAP were evaluated from October 2005 to October 2006. Sputum, bronchoalveolar lavage, and blood samples were collected for microbiological culture. Determination was performed for specific immunoglobulin M (IgM) for Chlamydia pneumoniae, Mycoplasma pneumoniae, Legionella pneumophila, Coxiella burnettii, adenovirus, and influenza virus. The most common isolated bacteria was Streptococcus pneumoniae (22%) followed by Haemophilus influenzae (18%). Mycoplasma pneumoniae was isolated from 5% and Legionella pneumophila was isolated from 5% of patients. The most common positive serological reaction was for Chlamydia pneumoniae (30%) and Adenovirus (30%). In the study of accuracy of determination of specific IgM for Mycoplasma pneumoniae and Legionella pneumophila compared to culture, the sensitivity was 60% and 80% respectively, specificity was 93.7 %, and 98.9 % respectively, and accuracy was 92 % and 97 % respectively. This study highlights the prominence of mixed bacterial/viral infections in lower respiratory tract infection diagnosis. Our data showed that at least 30% of our patients had concurrent infections. This observation raises two important questions: 1) whether sequential or concurrent viral and bacterial infections have a synergistic impact on the evolution of disease in children; and 2) should diagnostic batteries for any patient with CAP include methods for detecting both the typical and atypical bacterial or viral pathogens.

[Pneumonia caused by Haemophilus influenzae. Study in a series of 58 patients].

Haemophilus influenzae tends to form part of the usual respiratory flora in adults, especially if they have a chronic underlying disease or are smokers. Pneumonia due to H. influenzae is frequently involved in respiratory infections and its level of resistance to ampicillin has remained stable over the last five years. Most of the literature on the subject was published more than 10 years ago. In this study, we describe the clinical features and evolution of 58 adult patients admitted to hospital for pneumonia due to H. influenzae over a 2-year period, with this group accounting for 6.5% of all the patients admitted with pneumonia during this time period. The etiological diagnosis was made using a good quality sputum sample. Forty patients (69%) were male. The mean age (+/- SD) of the group was 67 (+/-16.8) years and all the patients had at least one underlying disease. The mean duration of the symptoms was 6.7 days. All patients presented an increase in the quantity or purulence of the sputum. On admittance, respiratory failure was present in 52 patients (90%). Gram-negative coccus-bacilli were observed in the direct sputum test and H. influenzae grew in the culture. In two cases, H. influenzae was recovered from the blood culture and in one from bronchial aspiration obtained through bronchoscopy. Another pathogen was identified in 28 patients (48%). In 21 it was another pyogenic bacteria (15 S. pneumoniae, 4 M. catharralis, 1 K. pneumoniae, 1 E. coli), an atypical microorganism in 5 (3 C. pneumoniae, 2 C. burnetii) and a respiratory virus in 2 (syncytial and influenza A). Atypical bacteria and respiratory virus were detected using serological techniques. The radiographic infiltrate was unilobar in 54 of the 58 patients and all showed an alveolar pattern. The empirical treatment included the administration of a third generation cephalosporin (or a fluoroquinolone in patients allergic to penicillin). The evolution was favorable in all the cases in which H. influenzae was the only pathogen or was accompanied by an atypical microorganism or a respiratory virus. Four patients with mixed bacterial pneumonia died (2 S. pneumoniae, 1 E. coli and 1 M. catharralis). The study indicates that pneumoniae due to H. influenzae affects a population with an underlying disease, preferably pulmonary, that it has a longer clinical period than that for pneumococcal pneumonia, that it is slightly bacteremic and, that, usually, it evolves benignly with a low mortality.

Prospective epidemiologic survey of patients with community-acquired pneumonia requiring hospitalization in Switzerland.

Community-acquired pneumonia (CAP) is a common problem and the principal infection requiring hospitalization, but its treatment is complicated by the difficulty in microbiological diagnosis and the increasing incidence of antibiotic resistance among respiratory pathogens. The purpose of this paper is to present the main epidemiologic features of patients with CAP requiring hospitalization in our country. We enrolled three hundred and eighteen adult patients with CAP requiring hospitalization in seven large medical centers in Switzerland during two winter periods. The patients' mean age was 70.4 years. This study describes the epidemiology of these patients. Clinical, radiologic and microbiological evaluations were performed at study entry during treatment, and at 4 weeks post-therapy. For microbiological diagnostic purposes, sputum culture, throat swab culture, PCR, blood cultures, Legionella urinary antigen and serologic evaluations were also performed. Despite the higher mean age, the overall mortality rate was 8%, lower than in other comparable studies. The most common underlying diseases present at study entry were cardiac failure (23%), chronic obstructive pulmonary disease (20%), renal failure (15%), and diabetes (12%); 40% of the patients were smokers. Although dyspnea, cough and positive pulmonary auscultation findings were present in about 90% of patients, fever >38 degrees C was present in only 64%. The most frequently isolated respiratory pathogens were Streptococcus pneumoniae (12.6%), Haemophilus influenzae (6%), Staphylococcus aureus (1.6%), and Moraxella catarrhalis (1.6%). Atypical pathogens were frequently found, with the following distribution: Mycoplasma pneumoniae, 7.5%; Chlamydia pneumoniae, 5.3%; and Legionella pneumophila, 4.4%. The mean duration between onset of symptoms and hospital admission was 4.8 days, and the mean treatment duration was 12.1 days. Two weeks after the start of therapy, although clinical symptoms were absent, radiologic infiltrates were still present in 24% of patients. The microbiological diagnosis in CAP can be established in only about 50% of cases with the combination of several diagnostic tools. Epidemiologic surveys of CAP should be performed on a regular basis, regionally, as a way to improve the management of these infections.

Atypical pathogens causing community-acquired pneumonia in adults.

To determine the frequency of community-acquired respiratory pathogens with special focus on atypical organisms in patients presenting to a tertiary care facility with community-acquired pneumonia (CAP). The descriptive study on adult patients was conducted from February 2007 to March 2008 at the Aga Khan University Hospital, Karachi. It comprised 124 consenting patients of age 16 and above who presentd with a diagnosis of community-acquired pneumonia. The diagnostic modalities used were based on significant changes in antibody titer or persisting high antibody titers in the case of Mycoplasma pneumoniae and Chalmydia pneumoniae infections, or bacterial antigen in urine, in the case of Legionella pneumophila serogroup 1 infection. Pyogenic bacteria were identified on the results of respiratory secretions or blood cultures. Continuous data and categorical variables were worked out using SPSS version 15. Among the 124 patients enrolled, an etiologic agent was identified in 44 (35.4%) patients. The most common organism was Mycoplasma pneumoniae (n = 21, 17%), followed by Chlamydia pneumoniae (n = 15, 12%), Streptococcus pneumoniae (n = 9, 7%), Haemophilus influenzae (n = 2, 1.6%), Klebsiella pneumoniae (n = 2, 1.6%) and Staphylococcus aureus (n = 1, 0.8%). Streptococcus pneumoniae was the most common organism isolated from blood cultures. No cases of Legionella pneumophila serogroup 1 were identified. Mycoplasma pneumoniae and Chalmydia pneumoniae are significant etiologic agents for community-acquired pneumonia occurring in Karachi. Local treatment guidelines for community-acquired pneumonia should include therapy directed specifically at these agents.

[Community-acquired pneumonia: prospective study of 101 adult, immunocompetent patients for 1 year].

A one year prospective study was carried out to assess the etiology of community-acquired pneumonia (CAP), and also to know the incidence, characteristics and evolution of infection by Chlamydia pneumoniae; and the effectiveness of DNA probes in CAP due to Mycoplasma pneumoniae and Legionella. One hundred and ten patients with a diagnosis of CAP in the emergency department were studied. Serologic studies were performed, and also tests commonly used for the diagnosis of respiratory tract pathogens in respiratory samples, including serology and culture of Chlamydia pneumoniae and DNA probes for Mycoplasma pneumoniae and Legionella. In 72 cases (71.3%) some pathogen was found and in 5 cases more than one microorganism was involved. The etiology was bacterial in 31% of the cases, with S. pneumoniae being the most frequent (19 cases). Forty percent of the cases were "atypical" pneumonias with 33 cases of M. pneumoniae and 5 by Chlamydia pneumoniae. Diagnostic data of viral pneumonia were found in 2 cases. DNA probes were not useful for the diagnosis of pneumonia by Legionella pneumophila and had low effectiveness (31.8%) in Mycoplasma pneumoniae CAP. a) M. pneumoniae was the most frequent pathogen (33%). b) DNA probes for M. pneumoniae had low sensitivity in sputum (31.8%) and none in pharyngeal exudate. c) Acute infection by C. pneumoniae was diagnosed in 5 cases. Previous data of infection were recorded in 60.4% of the patients. d) Bacterial pneumonia (31%) was underestimated due to a low rate of bacteremic cases (7.9%) and the low number of positive cultures with definitive diagnostic value. e) The evolution was good except in two cases (death due to staphylococcal pneumonia with alcohol withdrawal syndrome and multiorganic failure by disseminated chicken-pox).

Community-acquired pneumonia: epidemiologic and clinical considerations.

An incidence of between 2 and 44 per 1000 population has been reported for community-acquired pneumonia. Epidemiologic studies describe a wide range of causative organisms, including Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Legionella spp., Moraxella catarrhalis, Chlamydia pneumoniae and viruses such as influenza A and B. However, the frequency with which they are reported varies widely. On analysis of these studies, the variation can be explained by a number of factors. The results depend on the definition of pneumonia and the criteria for assigning a causative role to any particular organism. Older studies have not included diagnostic methods for newly described organisms such as C. pneumoniae and Legionella spp. The improved diagnostic methods for these organisms and for Mycoplasma pneumoniae are reflected in more recent studies. Further variation depends on the population studied. As many patients with mild pneumonia are successfully treated in the community, those studies that are hospital-based include patients with more severe pneumonia often in the elderly or in patients with underlying diseases such as chronic obstructive pulmonary disease. The prior use of antibiotics not only contributes to the high percentage of cases for which no etiologic agent is found, but also ensures that treatment failures are selected for hospitalization. This further changes the result, depending on the antibiotic agents used most commonly in the community. The inclusion of nursing home patients or groups where alcoholism is more common will also favor particular organisms. Finally, the timing of the study may be such that an epidemic is included. This has relevance mostly for Mycoplasma pneumoniae, C. pneumoniae, Legionella spp. and influenza. In the assessment of the patient with community-acquired pneumonia, any one of the above organisms can be considered to be responsible. As initial treatment is empirical, other information can be used to ensure that an antibiotic with an adequate spectrum is chosen. Factors of importance are age, underlying illness, severity of disease and any locally recognized epidemics or endemic organisms. Differences in clinical presentation are not sufficiently distinct to allow for accurate prediction of the causative agent. Similarly, chest radiograph changes are not sufficiently specific to discriminate reliably between diverse organisms such as S. pneumoniae, Mycoplasma pneumoniae and Legionella spp. Current recommendations for choice of an empirical antibiotic agent are therefore based, not on the assumption of a single etiologic agent indicated by clinical presentation or radiographic appearances, but on age of the patient, severity of illness, the presence of underlying conditions and the range of possible organisms in that patient group.

Guidelines for community-acquired pneumonia: are they reflected in practice?

Community-acquired pneumonia (CAP) is common, costly, and clinically serious. Several national and international practice guidelines have been developed to promote more appropriate, cost-effective care for patients with CAP. This article compares and contrasts eight international practice guidelines for the management of CAP, describes the extent to which recommendations are reflected in practice, and proposes explanations for non-adherence to guidelines. We found consistency in recommendations across all the guidelines for the management of patients with CAP requiring intensive care. In this setting, all guidelines recommend chest radiography, sputum Gram stain and culture, blood cultures, testing for Legionella pneumophila, and timely administration of antibiotics active against both typical (i.e. Streptococcus pneumoniae, Hemophilus influenzae) and atypical organisms (i.e. Legionella spp., Mycoplasma pneumoniae, and Chlamydia pneumoniae). Recommendations for the management of the average inpatient with pneumonia were more variable, with the greatest differences between the North American and European guidelines. The North American guidelines (in contrast to European ones), recommended empiric treatment of typical and atypical organisms in all inpatients. There were also differences in policies regarding the necessity of chest radiography, sputum studies, and serologic testing. Some guidelines explicitly embrace the use of prediction rules to inform the decision to hospitalize, while others do not. Some of these admission decision algorithms focus on identifying low risk patients, while others are most concerned with high risk patients. There was also considerable variation in the specificity and operationalization of clinical criteria for switching from parenteral to oral antibiotics or judging appropriateness for discharge. Many recommendations for key management decisions tended to lack explicit, objective, and actionable criteria that could be easily implemented in real world practice. Review of the pneumonia literature revealed that physician performance of guideline-recommended best practices is often suboptimal. Administration of timely antibiotics (< or =8 hours of presentation) and use of first-line antibiotics occurred in 75-85% and 18-79% of cases, respectively. Collection of blood cultures within 24 hours of presentation and prior to administration of antibiotics was achieved in 69-83% and 63-82% of cases, respectively. Screening the eligibility of CAP patients for hospital-based pneumococcal and influenza vaccination occurred on average in 11 and 14% of hospitalizations, respectively, in the US. Lack of awareness of guidelines, conflicting advice among them, and lack of specific, objective, actionable recommendations most likely contribute to nonadherence to CAP guidelines. Increased attention to these factors will be needed if professional society practice guidelines are to fulfill their promise as tools for improving the quality and outcomes of care for patients with pneumonia.

Study of community acquired pneumonia aetiology (SCAPA) in adults admitted to hospital: implications for management guidelines.

Since the last British study of the microbial aetiology of community acquired pneumonia (CAP) about 20 years ago, new organisms have been identified (for example, Chlamydia pneumoniae), new antibiotics introduced, and fresh advances made in microbiological techniques. Pathogens implicated in CAP in adults admitted to hospital in the UK using modern and traditional microbiological investigations are described. Adults aged 16 years and over admitted to a teaching hospital with CAP over a 12 month period from 4 October 1998 were prospectively studied. Samples of blood, sputum, and urine were collected for microbiological testing by standard culture techniques and new serological and urine antigen detection methods. Of 309 patients admitted with CAP, 267 fulfilled the study criteria; 135 (50.6%) were men and the mean (SD) age was 65.4 (19.6) years. Aetiological agents were identified from 199 (75%) patients (one pathogen in 124 (46%), two in 53 (20%), and three or more in 22 (8%)): Streptococcus pneumoniae 129 (48%), influenza A virus 50 (19%), Chlamydia pneumoniae 35 (13%), Haemophilus influenzae 20 (7%), Mycoplasma pneumoniae 9 (3%), Legionella pneumophilia 9 (3%), other Chlamydia spp 7 (2%), Moraxella catarrhalis 5 (2%), Coxiella burnetii 2 (0.7%), others 8 (3%). Atypical pathogens were less common in patients aged 75 years and over than in younger patients (16% v 27%; OR 0.5, 95% CI 0.3 to 0.9). The 30 day mortality was 14.9%. Mortality risk could be stratified by the presence of four "core" adverse features. Three of 60 patients (5%) infected with an atypical pathogen died. S pneumoniae remains the most important pathogen to cover by initial antibiotic therapy in adults of all ages admitted to hospital with CAP. Atypical pathogens are more common in younger patients. They should also be covered in all patients with severe pneumonia and younger patients with non-severe infection.

Pneumonia

Bacteria Bacteria are the most common cause of community-acquired pneumonia (CAP), with Streptococcus pneumoniae isolated in nearly 50% of cases. Other commonly isolated bacteria include Haemophilus influenzae in 20%, Chlamydophila pneumoniae in 13%, and Mycoplasma pneumoniae in 3% of cases; Staphylococcus aureus; Moraxella catarrhalis; and Legionella pneumophila. A number of drug-resistant versions of the above infections are becoming more common, including drug-resistant Streptococcus pneumoniae (DRSP) and methicillin-resistant Staphylococcus aureus (MRSA).

Atypical pneumonia

Epidemiology Mycoplasma is found more often in younger than in older people. Older people are more often infected by Legionella. Terminology "Primary atypical pneumonia" is called primary because it develops independently of other diseases. It is commonly known as "walking pneumonia" because its symptoms are often mild enough that one can still be up and about. "Atypical pneumonia" is atypical in that it is caused by atypical organisms (other than Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis). These atypical organisms include special bacteria, viruses, fungi, and protozoa. In addition, this form of pneumonia is atypical in presentation with only moderate amounts of sputum, no consolidation, only small increases in white cell counts, and no alveolar exudate.

[Pneumonia due to Haemophilus influenzae.Study in a series of 58 patients]

Haemophilus influenzae tends to form part of the usual respiratory flora in adults, especially if they have a chronic underlying disease or are smokers. Pneumonia due to H. influenzae is frequently involved in respiratory infections and its level of resistance to ampicillin has remained stable over the last five years. Most of the literature on the subject was published more than 10 years ago. In this study, we describe the clinical features and evolution of 58 adult patients admitted to hospital for pneumonia due to H. influenzae over a 2-year period, with this group accounting for 6.5&#37; of all the patients admitted with pneumonia during this time period. The etiological diagnosis was made using a good quality sputum sample. Forty patients (69&#37;) were male. The mean age (+/- SD) of the group was 67 (+/-16.8) years and all the patients had at least one underlying disease. The mean duration of the symptoms was 6.7 days. All patients presented an increase in the quantity or purulence of the sputum. On admittance, respiratory failure was present in 52 patients (90&#37;). Gram-negative coccus-bacilli were observed in the direct sputum test and H. influenzae grew in the culture. In two cases, H. influenzae was recovered from the blood culture and in one from bronchial aspiration obtained through bronchoscopy. Another pathogen was identified in 28 patients (48&#37;). In 21 it was another pyogenic bacteria (15 S. pneumoniae, 4 M. catharralis, 1 K. pneumoniae, 1 E. coli), an atypical microorganism in 5 (3 C. pneumoniae, 2 C. burnetii) and a respiratory virus in 2 (syncytial and influenza A). Atypical bacteria and respiratory virus were detected using serological techniques. The radiographic infiltrate was unilobar in 54 of the 58 patients and all showed an alveolar pattern. The empirical treatment included the administration of a third generation cephalosporin (or a fluoroquinolone in patients allergic to penicillin). The evolution was favorable in all the cases in which H. influenzae was the only pathogen or was accompanied by an atypical microorganism or a respiratory virus. Four patients with mixed bacterial pneumonia died (2 S. pneumoniae, 1 E. coli and 1 M. catharralis). The study indicates that pneumoniae due to H. influenzae affects a population with an underlying disease, preferably pulmonary, that it has a longer clinical period than that for pneumococcal pneumonia, that it is slightly bacteremic and, that, usually, it evolves benignly with a low mortality.

[Legionella dumoffii and Legionella pneumophila serogroup 5 isolated from 2 cases of fulminant pneumonia].

We encountered two cases of legionella pneumonia which ran a dramatic course and isolated Legionella dumoffii from one patient and Legionella pneumophila serogroup 5 from the other patient. The patient from whom L. dumoffii was isolated was a 59-year-old male with no basic disease. He presented chill, fever, coughing and other symptoms, starting on July 3, 1986, his disease was diagnosed as pneumonia at the clinic of his company. The patient was then introduced and admitted to our hospital. On admission chest radiography disclosed zonal pneumonia with an unclear border in the right superior lobe of the lung; a beta-lactam preparation was administered, but no effect was obtained and the lung lesion showed a rapid advance. From this condition, we suspected legionella pneumonia and changed the therapy to treatment with erythromycin and rifampicillin. Despite this, no improvement occurred and the patient died on the 26th hospital day. Colonies like Legionella colonies were separated from a total of seven specimens of biopsy aspirated matter from the airway and autopsy collected lung abscess and tracheal secretions, and the bacterium was identified L. dumoffii based on the biochemical and serological properties. In addition, the patient's serum was found to have an increased antibody titer against L. dumoffii. Based on these findings, the patient's disease was diagnosed as pneumonia as caused by L. dumoffii, a relatively rare bacterium as a member of the genus Legionella. The patient from whom Legionella pneumophila serogroup 5 was isolated was an 81-year-old man with basic diseases such as heart failure, anemia and hypothyroidism. He presented fever, general fatigue, anorexia and other symptoms, starting around June 2, 1987; pneumonia was suspected and the patient was urgently admitted to our hospital. The patient died of pneumonia of unknown cause on the second hospital day. To clarify the cause, autopsy was conducted; a large number of colonies like Legionella colonies were noted in the lung tissue. Identification test was then conducted and the bacterium was identified as L. pneumophila; we concluded that the patient's pneumonia had been caused by the identified bacterium L. pneumophila. The isolate was further subjected to slide agglutination test and identified as L. pneumophila serogroup 5.

[Community acquired pneumonia in patients older than 60 years. Incidence of atypical agents and clinical-radiological progression].

Seventy five patients older than 60 years with a community acquired pneumonia followed up in an outpatient clinic, were prospectively studied in order to determine the incidence of atypical agents, clinical-radiological characteristics, progression and the differences with pneumonia in younger patients. Clinical-radiological evaluation protocols were activated in the first visit and in two subsequent controls. Etiological diagnosis was made by means of serology (in the first visit and three weeks later). Initially, 85 patients older than 60 years were included of which 75 non hospitalized were fully followed up. Also, in the comparative study, 216 outpatient clinic patients 60 years old or younger were followed up during the same period. In the first group the frequency of atypical agents was 33.3%. The most frequently isolated bacteria was Coxiella burnetii (13.3%)followed by virus and Legionella pneumophila. No case of Mycoplasma pneumoniae was diagnosed. The most frequent radiological onset was alveolar infiltrate (85%). The comparative study between the two populations (older or younger than 60 years), found few clinical differences (dyspnea more frequent in older,feverish chill in younger) and auscultation (crackles more frequent in older). We did not find differences remaining clinical-radiological or laboratory data. Most patients presented a favourable clinical and radiological progression. Only 2 patients needed hospital admission (2.7%). In outpatient clinic patients older than 60 years with community acquired pneumonia a high number of atypical agents have been found. The clinical-radiological evolution was satisfactory for most of them. Age was not a decisive element in determining hospital admissions.

Pneumococcal pneumonia

Pneumococcal pneumonia is a type of bacterial pneumonia that is caused by Streptococcus pneumoniae (which is also called pneumococcus). It is the most common bacterial pneumonia found in adults, the most common type of community-acquired pneumonia, and one of the common types of pneumococcal infection. The estimated number of Americans with pneumococcal pneumonia is 900,000 annually, with almost 400,000 cases hospitalized and fatalities accounting for 5-7% of these cases. The symptoms of pneumococcal pneumonia can occur suddenly, typically presenting as a severe chill, later including a severe fever, cough, shortness of breath, rapid breathing, and chest pains. Other symptoms like nausea, vomiting, headache, fatigue, and muscle aches could also accompany the original symptoms. Sometimes the coughing can produce rusty or blood-streaked sputum. In 25% of cases, a parapneumonic effusion may occur. Chest X-rays will typically show lobar consolidation or patchy infiltrates.

Prospective study of community-acquired pneumonia of bacterial etiology in adults.

The aim of this study was to prospectively analyze the bacterial etiology of community-acquired pneumonia in adults in Spain. From May 1994 to February 1996, 392 episodes of CAP diagnosed in the emergency department of a 600-bed university hospital were studied. An etiological diagnosis based on noninvasive microbiological investigations was achieved in 228 cases (58%); 173 of these diagnoses were definitive and 55 probable. Streptococcus pneumoniae, which caused 23.9% of the episodes, was the predominant pathogen observed, followed by Chlamydia pneumoniae (13.5%) and Legionella pneumophila (12.5%). Other less frequent pathogens found were Haemophilus influenzae (2.3%), Pseudomonas aeruginosa (1.5%), Mycoplasma pneumoniae (1.3%), Coxiella burnetii (1%), Moraxella catarrhalis (2 cases), Nocardia spp. (2 cases), and Staphylococcus aureus (2 cases). Streptococcus pneumoniae was significantly more frequent in patients with underlying disease and/or age > or =60 years (28% vs. 13%, P = 0.002), while Legionella pneumophila was more frequent in patients below 60 years of age and without underlying disease (20% vs. 9%, P = 0.006). Likewise, Streptococcus pneumoniae and Legionella pneumophila were the most frequent etiologies in patients requiring admission to the intensive care unit, occurring in 29% and 26.3% of the patients, respectively. In addition to Streptococcus pneumoniae, other microorganisms such as Chlamydia pneumoniae and Legionella spp. should be seriously considered in adults with community-acquired pneumonia when initiating empiric treatment or ordering rapid diagnostic tests.

[Community-acquired pneumonia: 573 cases].

To evaluate the epidemiology and incidence of community-acquired pneumonia (CAP) a retrospective study of 573 cases which had been diagnosed during a 3 1/2 year period was carried out. There was a male predominance (2.09/1) with mean age of 53.33 years. The diagnostic delay (days) was 1.5. The mean hospital stay was 13.39 days. The most common underlying disease was COLD (27%). 34% of patients had received previous therapy. The most common clinical features were cough, fever, and mucous sputum. The most common radiological pattern was alveolar (81%). There was increased ESR and moderately high GOT and GPT. The microbiological diagnosis was achieved in 35.4%, with positive sputum culture (mostly pneumococcus) in 26.8% an positive blood culture in 5.9%. Ten patients died (1.7%). The following factors predicted a poor prognosis: age 75 years, underlying disease, bilateral radiological involvement and leukocytosis with neutrophilia.

InternalMed_Harrison

presenting manifestations The presentation of pneumococcal pneumonia does not reliably distinguish it from pneumonia of other etiologies. In a subset of cases, pneumococcal pneumonia is recognized at the outset as associated with a viral upper respiratory infection and is characterized by the abrupt onset of cough and dyspnea accompanied by fever, shaking chills, and myalgias. The cough evolves from nonpurulent to productive of sputum that is purulent and sometimes tinged with blood. Patients may describe stabbing pleuritic chest pain and significant dyspnea indicating involvement of the parietal pleura. Among the elderly, the presenting clinical symptoms may be less specific, with confusion or malaise but without fever or cough. In such cases, a high index of suspicion is required because failure to treat pneumococcal pneumonia promptly in an elderly patient is likely to result in rapid evolution of the infection, with increased severity, morbidity, and risk of death.

A case report of Legionella and Mycoplasma pneumonia: Co-incidence or co-infection?

Concurrent or sequential coinfections of Legionella pneumophila and Mycoplasma pneumoniae have been reported in the past though infrequently. Distinguishing a true co-infection from cross reactivity is often challenging as the diagnosis is mostly dependent on serological testing. A 77-year-old male presented with worsening dyspnea, cough with yellow sputum, diarrhea and fever of 2-days duration. Patient had history of chronic obstructive pulmonary disease (COPD) on home oxygen, bronchiectasis, rheumatoid arthritis (on methotrexate and leflunomide), treated pulmonary tuberculosis and 30-pack-year smoking. Chest X-ray showed bilateral interstitial changes with left lower lobe infiltrate. On day 5, his urine antigen for L pneumophila serogroup 1 was reported positive. The following day his serum M pneumoniae IgM antibody titers were reported elevated at 6647 U/mL. Patient was started on antibiotics and placed on non-invasive positive pressure ventilation. The patient was diagnosed with possible Legionella and Mycoplasma co-infection. Sputum Mycoplasma polymerase chain reaction (PCR) and serum cold agglutinins were obtained on day 6 and later reported negative. He was treated with azithromycin for 10 days with clinical improvement. Serological testing alone is an indirect measure with poor sensitivity and specificity and has its own limitations. Urine antigen detection confirms L pneumophila serogroup 1 infection in a patient with suggestive symptoms. However, diagnosis of M pneumonia should be based on combination of tests including serology and PCR to confirm true co-infection.

Delafloxacin

Susceptible bacteria for CABP are: Streptococcus pneumoniae, Staphylococcus aureus (methicillin-susceptible [MSSA] isolates only), Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Haemophilus influenzae, Haemophilus parainfluenzae, Chlamydia pneumoniae, Legionella pneumophila, and Mycoplasma pneumoniae. It has not been tested in pregnant women. In the European Union it is indicated for the treatment of acute bacterial skin and skin structure infections (ABSSSI) in adults when it is considered inappropriate to use other antibacterial agents that are commonly recommended for the initial treatment of these infections.

[Comparative study of clinical features of typical and atypical pneumonias].

We prospectively analyzed the clinical and laboratory features of 74 patients with community-acquired pneumonia who required hospitalization between May 1996 and October 1997. Typical pathogens were identified in 47, and atypical pathogens in 27. The average age was higher in patients affected by typical pathogens (73.9 years), than in patients affected by atypical pathogens (50.9 years). Univariable analysis found that atypical pneumonias were more frequent in healthy patients than typical pneumonias. Moreover, the presence of relatives with symptoms of airway infection, headache, and earache was more common among the patients with atypical pneumonias, while leukocytosis and elevated C-reactive protein levels were more frequent among patients with typical pneumonias. Typical pathogens accounted for up to 79.6% of the cases of pneumonia with in older patients (aged 60 years or more), whereas atypical pathogens accounted for up to 80% of the cases of pneumonia in younger patients (aged under 60 years). This difference was statistically significant. Of all 74 patients, 39 (52.7%) were afflicted by severe community-acquired pneumonia, as categorized by American Thoracic Society guidelines. The most common pathogen among these patients was Streptococcus pneumoniae. Legionella was one of the top four. Selection of the initial antimicrobial treatment is an important clinical decision that should be made on the basis of clinical features at admission, age, and severity of the patient's illness.

[Community-acquired pneumonia (CAP) with hospital treatment. The value of the clinical picture and complementary exams in predicting its etiology].

We studied 162 patients with community-acquired pneumonia admitted for hospital treatment, in order to determine the utility of clinical and ancillary examinations for predicting etiology and guiding the most appropriate empirical treatment. Acute first appearance of symptoms, purulent expectoration, chest sounds indicating lung condensation, pleuritic chest pain and leukocytosis over 12,500/ml were statistically significant in differentiating typical pneumonias from those with atypical behavior patterns. The last two features were the most relevant according to multivariate analysis. We conclude that careful taking of case histories and basic blood testing continue to be relevant and must not be considered anachronistic for the differential diagnosis of community-acquired pneumonias.

[Diagnosis, treatment and prognosis of community acquired pneumonia - results from three primary care centers in Iceland].

To study how general practitioners diagnose and treat adult patients with community acquired pneumonia (CAP) and evaluate outcomes. Retrospective chart review for one year on patients 18 years and older diagnosed with CAP in three different primary care centers in Iceland. A total of 215 patients were diagnosed with CAP. Of those 195 were both diagnosed and treated in the primary health care and 20 patients were referred for specialized care. Mean age was 50.3 years (SD= 21.0) and 126 (65%) of the patients were women. Most patients had been ill for less than a week and did not have a previously diagnosed lung disease. Cough was the most common symptom (71%) and 96% had abnormal chest auscultation. Vital signs were frequently not recorded. A chest radiograph was done in third of the cases and showed abnormality in over 80%. Most patients (94%) were treated with antibiotics usually extended spectrum penicillin. Phone consultations were the most common form of communication after diagnosis and about 12% of subjects had their antibiotics changed and about 10% had a chest radiograph done after diagnosis had been made. There was no mortality from CAP during the study period. CAP was diagnosed clinically and managed in primary care in most cases. CAP was more common in women and a minority of patients had underlying lung diseases. Vital sign measurements were used less than expected. Broad spectrum antibiotics were widely used for treatment. CAP had no mortality.

[A multicentre study on the pathogenic agents in 665 adult patients with community-acquired pneumonia in cities of China].

To investigate the pathogenic causes of community-acquired pneumonia (CAP) in adult patients in China, the relation of previous antibiotic use and the Pneumonia Patient Outcome Research Team (PORT) classification to microbial etiology, and the prevalence of drug resistance of common CAP bacteria. A prospective study was performed on 665 consecutive adult patients with CAP at 12 centers in 7 Chinese cities during one year. The etiology of pneumonia was considered if one of the following criteria was met: (1) valid sputum sample yielding one or more predominant strains; (2) blood cultures yielding a bacterial pathogen; (3) seroconversion, a > or = 4-fold increase or decrease titers of antibodies to Mycoplasma pneumoniae, Chlamydia pneumoniae and Legionella pneumophila. Minimum inhibitory concentration (MIC) of respiratory tract isolates was determined using the agar dilution method. Pathogens were identified in 324/610 patients (53.1%) with valid serum samples and sputum cultures as follows: Mycoplasma pneumoniae (126, 20.7%), Streptococcus pneumoniae (63, 10.3%), Haemophilus influenzae (56, 9.2%), Chlamydia pneumoniae (40, 6.6%), Klebsiella pneumoniae (37, 6.1%), Legionella pneumophila (31, 5.1%), Staphylococcus aureus (23, 3.8%), Escherichia coli (10, 1.6%), Moraxella catarrhalis (8, 1.3%), Pseudomonas aeruginosa (6, 1.0%). Of 195 patients with a bacterial pathogen, an atypical pathogen was identified in 62 (10.2%) cases. The non-susceptibility rate of Streptococcus pneumoniae to penicillin, azithromycin, and moxifloxacin was 20.3%, 75.4% and 4.3% respectively. Atypical pathogens have important role in CAP, with Mycoplasma pneumoniae being the most common pathogen, and mixed infection of atypical pathogens with bacteria was found in 10.2% of the cases. Streptococcus pneumoniae and Haemophilus influenzae remain the most important bacteria for CAP. More than 75.0% of Streptococcus pneumoniae was resistant to macrolides and 20.3% was resistant to penicillin.

[Etiology of community-acquired pneumonia among adult patients in Japan].

To clarify the etiology of community-acquired pneumonia (CAP) in Japan, the causative pathogens were prospectively investigated in adult patients admitted to Kurashiki Central Hospital. The microbiological diagnosis was based on the results of quantitative sputum culture, blood culture, and other invasive procedures, including transthoracic needle aspiration or bronchoscopic examination. Five hundred fifty-two episodes of CAP in 540 patients were admitted between July 1994 and June 1999. Causative pathogens were identified in 353 episodes (63.9%). Several characteristics about the etiology of CAP in Japan were recognized: 1) Streptococcus pneumoniae is the most common pathogen followed by Haemophilus influenzae; 2) Mycoplasma pneumonia is dominant among young patients; 3) Chlomydia pneumoniae is one of the significant pathogens in Japan as well as in western countries; 4) Streptococcus milleri group and anaerobes are important pathogens in patients with suppurative pulmonary diseases; 5) The incidence of Legionella pneumonia is far lower than in western countries; 6) The prevalence of tuberculosis in CAP is still high in Japan; etc. Recognition of these results will lead us to treat patients with prompt antimicrobial therapy.

Comparative study of the clinical presentation of Legionella pneumonia and other community-acquired pneumonias.

The aim of this study was to compare the clinical, biological, and radiologic features of presentation in the emergency ward of community-acquired pneumonia (CAP) by Legionella pneumophila (LP) and other community-acquired bacterial pneumonias to help in early diagnosis of CAP by LP. Three hundred ninety-two patients with CAP were studied prospectively in the emergency department of a 600-bed university hospital. Univariate and multivariate analyses were performed to compare epidemiologic and demographic data and clinical, analytical, and radiologic features of presentation in 48 patients with CAP by LP and 125 patients with CAP by other bacterial etiology (68 by Streptococcus pneumoniae, 41 by Chlamydia pneumoniae, 5 by Mycoplasma pneumoniae, 4 by Coxiella burnetii, 3 by Pseudomonas aeruginosa, 2 by Haemophilus influenzae, and 2 by Nocardia species. Univariate analysis showed that CAP by LP was more frequent in middle-aged, male healthy (but alcohol drinking) patients than CAP by other etiology. Moreover, the lack of response to previous beta-lactamic drugs, headache, diarrhea, severe hyponatremia, and elevation in serum creatine kinase (CK) levels on presentation were more frequent in CAP by LP, while cough, expectoration, and thoracic pain were more frequent in CAP by other bacterial etiology. However, multivariate analysis only confirmed these differences with respect to lack of underlying disease, diarrhea, and elevation in the CK level. We conclude that detailed analysis of features of presentation of CAP allows suspicion of Legionnaire's disease in the emergency department. The initiation of antibiotic treatment, including a macrolide, and the performance of rapid diagnostic techniques are mandatory in these cases.

Clinical differentiation of atypical pneumonia using Japanese guidelines.

Atypical pneumonia occupies an important position in community-acquired pneumonia. The aim of this study was to examine whether making a diagnosis of atypical pneumonia is possible based upon the Japanese Respiratory Society guidelines. The data from three prospective studies were reviewed. A total of 285 patients with mycoplasmal pneumonia or chlamydial pneumonia and 515 patients with pneumococcal pneumonia or Haemophilus influenzae pneumonia were assessed to determine whether these pneumonias met the diagnostic criteria for atypical pneumonia used in the Japanese Respiratory Society guidelines. The criteria were: (i) age less than 60 years; (ii) no or only minor underlying diseases; (iii) persistent cough; (iv) limited chest auscultatory findings; (v) no sputum, or no identified aetiological agent by rapid diagnosis; and (vi) a peripheral white blood cell count below 10,000/microL. All items of the criteria proved to be valid except for 'age' in patients with Chlamydophila pneumoniae pneumonia using multiple regression analysis. The sensitivity and specificity for atypical pneumonia were 77.0% and 93.0% based on four or more of the criteria respectively. Pure atypical pneumonia can be differentiated to some degree by clinical symptoms and laboratory findings. It is important to differentiate and treat bacterial pneumonia and atypical pneumonia in regions such as Japan, where Streptococcus pneumoniae resistance to macrolides is high. Treatment covering the two types of pneumonia should be considered in elderly patients and those with underlying respiratory disease.