Mixed community-acquired pneumonia in hospitalised patients.

The role of mixed community-acquired pneumonia (CAP) is controversial. The aim of the present study was to determine the incidence, principal microbial patterns, clinical predictors and course of mixed CAP. The current study included 1,511 consecutive hospitalised patients with CAP. Of these, 610 (40%) patients had an established aetiology. One pathogen was demonstrated in 528 patients and 82 (13%) patients had mixed pneumonia. Cases including CAP, by a pyogenic bacteria and a complete paired serology for "atypicals", revealed that 82 (13%) patients had definite single pyogenic pneumonia and 28 patients (5%) had mixed pyogenic pneumonia. In patients with mixed CAP, Streptococcus pneumoniae was the most prevalent microorganism (44 out of 82; 54%). The most frequent combination was S. pneumoniae with Haemophilus influenzae (17 out of 82; 21%). Influenza virus A and S. pneumoniae (five out of 28; 18%) was the most frequent association in the mixed pyogenic pneumonia group. No clinical predictors for mixed pneumonias could be identified. Patients with mixed pyogenic pneumonia more frequently developed shock when compared with patients with single pyogenic pneumonia (18 versus 4%). In conclusion, mixed pneumonia occurs in >10% of cases with community-acquired pneumonia requiring hospitalisation.     

Clinical analysis of community-acquired pneumonia in the elderly

OBJECTIVE: To evaluate the clinical features, etiology, and outcome of patients over 65 years old hospitalized for community-acquired pneumonia. PATIENTS: Eighty-four patients (50 males, 34 females) hospitalized for community-acquired pneumonia in Kawasaki Medical School Kawasaki Hospital between April 1998 and March 2000. RESULTS: Most of the patients had respiratory symptoms or signs, but over one-third also had atypical symptoms of pneumonia such as dyspnea, consciousness disturbance, and gastrointestinal symptoms. The causative microorganisms were identified in 48% of these patients. Streptococcus pneumoniae (13%), respiratory viruses (13%), Haemophilus influenzae (8%) and Mycobacterium tuberculosis (8%) were frequently identified, but Mycoplasma pneumoniae was less frequently noted in the elderly. Double infection was recognized in 19 % and a combination of some virus and bacteria in 13%. Treatment consisted of the administration of second or third generation cephalosporin antibiotics intravenously, because antibiotics had already been preadministered in 39%. The prognosis was poor (mortality rate 9%) for the elderly with community-acquired pneumonia despite mechanical ventilation in 8%. CONCLUSIONS: Although the range of microorganisms causing community-acquired pneumonia differed slightly from that in previous reports; namely, lower frequency of Chlamydia pneumoniae and Legionella pneumophila, it is suggested that the initial antibiotic treatment should always cover S. pneumoniae and H. influenzae. In addition, since a prevalence of virus infections related to the increase in community-acquired pneumonia in the elderly was found in this study, the routine use of influenza vaccine and pneumococcal vaccines in the elderly is recommended to reduce the high mortality rate.     

Community-acquired pneumonia with rhabdomyolysis]

We assessed the frequency and etiology of rhabdomyolysis in patients with community-acquired pneumonia. In 594 patients with community-acquired pneumonia whose serum CPK were measured, 25 patients (2.4%) were found to have rhabdomyolysis. Including 4 patients with mixed infections, the etiologies in 25 patients with community-acquired pneumonia with rhabdomyolysis were as follows: Legionella species, 11 patients (44%); Influenza virus, 6 (24%); Streptococcus pneumoniae, 4 (16%); Chlamydia psittaci, 3 (12%); Mycoplasma pneumoniae, 2 (8%); unknown 3 patients (12%). The rates of rhabdomyolysis for each etiologic category were as follows: Legionella species, 26.8% (11/41); Chlamydia psittaci, 21.4% (3/14); Influenza virus, 9.5% (6/63) ; Streptococcus pneumoniae, 4.7% (4/85);Mycoplasma pneumoniae, 3.1% (2/65). Renal dysfunction with a serum creatinine concentration greater than 1.5 mg/dl occurred in 6 patients (24%). Our experience illustrates that 5 pathogens can cause rhabdomyolysis in patients with community-acquired pneumonia. Legionella species are the most common organisms followed by Influenza virus, Streptococcus pneumoniae, Chlamydia psittaci, Mycoplasma pneumoniae.     

Microbiology of sinusitis

Most sinus infections are viral, and only a small proportion develops a secondary bacterial infection. Rhinoviruses, influenza viruses, and parainfluenza viruses are the most common causes of sinusitis. The most common bacteria isolated from pediatric and adult patients with community-acquired acute purulent sinusitis are Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pyogenes. Staphylococcus aureus and anaerobic bacteria (Prevotella and Porphyromonas, Fusobacterium and Peptostreptococcus spp.) are the main isolates in chronic sinusitis. Pseudomonas aeruginosa and other aerobic and facultative gram-negative rods are commonly isolated from patients with nosocomial sinusitis, the immunocompromised host, those with HIV infection, and in cystic fibrosis. Fungi and Pseudomonas aeruginosa are the most common isolates in neutropenic patients. The microbiology of sinusitis is influenced by the previous antimicrobial therapy, vaccinations, and the presence of normal flora capable of interfering with the growth of pathogens.     

Differences in the etiology of community-acquired pneumonia according to site of care: a population-based study

BACKGROUND: A few population-based studies assessing the etiology of community-acquired pneumonia in both hospitalized and ambulatory patients, with special emphasis on the etiologic role of viral infections, have been reported. The purpose of this study was to assess microbiological differences according to initial site of care in patients with community-acquired pneumonia. METHODS: We studied 496 patients > 14 years of age collected from the study samples of three population-based studies carried out in the same geographical area ("Maresme" region in the Mediterranean coast in Barcelona, Spain) with the same methodology over an 8-year period (1987-1995). RESULTS: Fifty-six percent of patients were hospitalized and 44% were treated at home. Of the 474 patients with etiological evaluation, 195 patients had an identifiable etiology (overall diagnostic yield 41%). Streptococcus pneumoniae was the most common causative organism. Viral infection was diagnosed in 26.5% of hospitalized patients vs. 13.2% of ambulatory patients (P=0.03). Twenty-five percent of the 68 patients with documented etiology treated at home had Chlamydia pneumoniae infection compared with 14.3% of those treated in the hospital. Ten percent of hospitalized patients had pneumonia caused by two pathogens compared with 9.7% of ambulatory patients. The association of viruses and bacteria was the most frequent cause of dual infection (79% inpatients, 67% outpatients). CONCLUSIONS: This study has provided information on etiology of community-acquired pneumonia in hospitalized patients and in patients treated at home. A considerable proportion of patients had viral pneumonia, frequently requiring hospital admission for inpatient care.     

Epidemiology of community-acquired pneumonia in adults: a population-based study.

In this prospective study, the authors assessed the incidence, aetiology, and outcome of patients with community-acquired pneumonia in the general population. From December 1993 to November 1995, a study was performed in a mixed residential-industrial urban population of the "Maresme" region in Barcelona, Spain. All subjects > or =14 yrs of age (annual average population size 74,368 inhabitants) with clinically suspected community-acquired pneumonia were registered. All cases were re-evaluated by chest radiographs on the 5th day of illness and at monthly intervals until complete recovery. Urine and blood samples were obtained for culture and antigen detection. When lower respiratory tract secretions were obtained, these were also cultured. There were 241 patients with community-acquired pneumonia, with an annual incidence rate of 1.62 cases (95% confidence interval, 1.42-1.82) per 1,000 inhabitants. Incidence rates increased by age groups and were higher in males than in females. Of 232 patients with aetiological data, 104 had an identifiable aetiology. A total of 114 pathogens were found (single pathogen 94, two pathogens 10). There were 81 episodes of bacterial infection and 33 of viral infection. The most common pathogens were Streptococcus pneumoniae, Chlamydia pneumoniae, and influenza A and B viruses. No case of Hantavirus infection was found. The rate of hospital admission was 61.4% with a mean+/-SD length of 11.7+/-10.1 days, a mean period of 23.0+/-14.3 days inactivity, and an overall mortality rate of 5%. The high rate of hospital admission, prolonged stay in hospital, and long period of inactivity all continue to constitute a social and health care burden of community-acquired pneumonia.     

Microbiology and risk factors for community-acquired pneumonia

The outcome of community-acquired pneumonia (CAP) depends on the interaction between the infectious agent and the host response. Nowadays the etiology of CAP can be established in ~60% of the cases, and Streptococcus pneumoniae remains the main etiological agent in outpatients, those hospitalized, or those requiring intensive care unit (ICU) admission. Recently, the development of nucleic acid amplification techniques has emphasized the role of viruses as important etiological agents in CAP. However, some demographic factors and comorbidities will determine a higher risk of pneumonia. Thus elderly patients or those with toxic habits (smoking, alcohol abuse), and the presence of various comorbidities (respiratory, metabolic, or renal) favor the development of pneumonia by altering the inflammatory response to infection.Some medications like inhaled corticosteroids could play a role in CAP development in chronic obstructive pulmonary disease (COPD) patients. Fortunately some of these risk factors are preventable and modifiable, for example, through smoking cessation and pneumococcal and influenza vaccinations, which are the biggest successes.     

Comparison of community-acquired pneumonia in relation to influenza A and RS virus infections

We experienced 142 cases with community-acquired pneumonia between April 1998 and March 2000. By measuring the titers of respiratory viruses for these cases, we were able to identify acute phase infections of influenza A virus in 10 cases and RS virus in 6 cases and determined that there was an increase in community-acquired pneumonia during both winter seasons. Thereafter we compared the clinical features of community-acquired pneumonia with regard to these two types of virus infection by dividing the patients into two groups, both of which frequently included in the elderly. In the influenza virus group, such general symptoms as high fever, headache and general fatigue were dominant. Common bacteria were isolated in nine cases with mixed infection; four of them with Streptococcus pneumoniae. In the RS virus group, there were fewer general symptoms and common bacteria were isolated in four cases with mixed infection; three with Haemophilus influenzae. The severity of the illness was greater in the Influenza virus group; i.e.) three cases required mechanical ventilation and two of these three cases died. In the RS virus group, on the other hand, the prognosis was good because no mechanical ventilation was required and there were no deaths. Influenza vaccination is especially important for the elderly, because the epidemiology of the influenza virus groups showed none had a history of influenza vaccination in this study.     

Clinical presentation of community-acquired Chlamydia pneumoniae pneumonia in adults

STUDY OBJECTIVE: To investigate the clinical presentation of community-acquired Chlamydia pneumoniae pneumonia in adults. DESIGN: Prospective study. SETTING: Kawasaki Medical School Hospital, Kawasaki Medical School Kawasaki Hospital, and Kurashiki Daiichi Hospital in Japan. PARTICIPANTS: Forty patients with community-acquired pneumonia with C pneumoniae as the only pathogen identified admitted to three hospitals between April 1996 and March 2001 and their clinical presentations were compared to patients with Streptococcus pneumoniae and Mycoplasma pneumoniae pneumonia. MEASUREMENTS: The diagnosis of C pneumoniae infection was based on isolation and serologic testing of antibodies by the microimmunofluorescence test. RESULTS: The clinical presentations, except for shortness of breath, were similar for the three major etiologic agents. The mean temperature of C pneumoniae patients on hospital admission was 37.9 degrees C, which was lower than that of patients with S pneumoniae and M pneumoniae. The mean WBC count on hospital admission was lower in the patients with C pneumoniae (mean, 9,100/microL) than in those with S pneumoniae pneumonia but higher than in those with M pneumoniae pneumonia. No patients required respiratory support or admission to an ICU, and no deaths occurred among the C pneumoniae pneumonia patients. CONCLUSIONS: Our results indicate that C pneumoniae pneumonia as a single etiologic agent is mild and that the underlying conditions and clinical symptoms closely resemble those of S pneumoniae pneumonia. However, the physical examinations, laboratory findings, and prognostic factors of the C pneumoniae patients resembled those of patients with M pneumoniae pneumonia.     

Bacterial pneumonia in patients with the acquired immunodeficiency syndrome

Eighteen episodes of community-acquired bacterial pneumonia were diagnosed in 13 patients among 336 with the acquired immunodeficiency syndrome (AIDS) cared for at Memorial Sloan-Kettering Cancer Center since 1979. Bacterial pathogens isolated in 16 of 18 episodes were Haemophilus influenzae in 8, Streptococcus pneumoniae in 6, group B streptococcus in 1, and Branhamella catarrhalis in 1. Eight episodes were presumed Pneumocystis carinii pneumonia until cultures obtained at bronchoscopy confirmed a bacterial cause. Specific antibacterial therapy was curative in 16 of 18 episodes; 2 patients died. Given an estimated yearly incidence of pneumococcal pneumonia in the general population of 2.6/1000, 1.09 cases were expected in our patients with AIDS; we saw 6 (p = 0.001), for an attack rate of 17.9/1000. Bacteria associated with B-cell defects should be anticipated when formulating empiric antibiotic therapy, pending a definitive diagnosis, for pulmonary infiltrates in patients with AIDS.     

Microbial etiology of community-acquired pneumonia in the adult population of 4 municipalities in eastern Finland.

To determine the etiology of community-acquired pneumonia in the adult population of a defined area, specific antibody responses in paired serum samples, levels of circulating pneumococcal immune complexes in serum samples, and pneumococcal antigen in urine were measured. Samples (304 paired serum samples and 300 acute urine samples) were obtained from 345 patients > or =15 years old with community-acquired, radiologically confirmed pneumonia, which comprised all cases in the population of 4 municipalities in eastern Finland during 1 year. Specific infecting organisms were identified in 183 patients (including 49 with mixed infection), as follows: Streptococcus pneumoniae, 125 patients; Haemophilus influenzae, 12; Moraxella catarrhalis, 8; chlamydiae, 37 (of which, Chlamydia pneumoniae, 30); Mycoplasma pneumoniae, 30; and virus species, 27. The proportion of patients with pneumococcal infections increased and of those with Mycoplasma infections decreased with age, but for each age group, the etiologic profile was similar among inpatients and among outpatients. S. pneumoniae was the most important etiologic agent. The annual incidence of pneumococcal pneumonia per 1000 inhabitants aged > or =60 years was 8.0.     

Etiology and management of community-acquired pneumonia in Asia

The causative organisms of community-acquired pneumonia, especially in Japan and Korea, are essentially similar to those in Western countries. If there are any differences, these are due to the laboratory tests and criteria used to define pathogenicity. Overall, Streptococcus pneumoniae is the most frequently occurring pathogen and Haemophilus influenzae, Mycoplasma pneumoniae, Chlamydia pneumoniae and viruses follow. Legionella spp. look likely to be low frequency pathogens in Asian countries, but a reason for this might be limitations of the laboratory tests used. A high frequency of Gram-negative bacilli as pathogens of community-acquired pneumonia in some Asian countries may be due to different criteria used to identify disease-causing organisms. A small number of papers about antibiotic resistance have shown no large differences between Asian countries, but considerable differences to Western countries, such as frequency of macrolide-resistant S. pneumoniae. Some Asian countries have their own guidelines for community-acquired pneumonia, but these are written in their own languages.     

Pneumonia in the elderly

PURPOSE OF REVIEW: This review provides an update on new data about the etiology, clinical characteristics, outcomes, and prevention of community-acquired pneumonia. The impact of severe acute respiratory syndrome in older persons is also addressed. RECENT FINDINGS: Streptococcus pneumoniae remains the most important cause of community-acquired pneumonia in the very elderly (80 years and over). Pneumococcus is also an important etiologic agent of pneumonia in residents of long-term care facilities. Clinical signs and symptoms of community-acquired pneumonia are less distinct in this group compared with younger patients. New data about influenza immunization reveal better mucosal immunity with the intranasal vaccine compared with the intramuscular vaccine. A review of clinical trial evidence differs from observational studies that demonstrate a clear benefit of the polysaccharide pneumococcal vaccine in the elderly. The prospect of severe acute respiratory syndrome in older adults is the most important new issue to emerge, as older adults are at increased risk from complications and death. SUMMARY: There are many challenges in preventing and managing community-acquired pneumonia in the elderly. S. pneumoniae remains the most important cause. The clinical presentation of pneumonia in the very elderly can be nonspecific. Given the safety profile of the vaccine and supportive observational evidence, public health policymakers should continue to support use of the polysaccharide pneumococcal vaccine. However, research into new vaccine strategies, including use of conjugate or common antigen vaccines, is a priority.     

Chlamydia species as a cause of community-acquired pneumonia in Canada.

Chlamydia pneumoniae has been implicated as a cause of community-acquired pneumonia (CAP) in several studies. However, there has been no comprehensive study of the role of Chlamydia species (C. pneumoniae, C. psittaci (avian and feline strains) and C. pecorum) as a cause of CAP. The aim of the present study was to determine the role of C. pneumoniae, C. psittaci and C. pecorum as causes of CAP. A prospective cohort observational study of CAP was conducted at 15 teaching centres in eight Canadian provinces between January 1996-October 1997. Acute (n=539) and convalescent (n=272) serum samples were obtained for determination of antibody titres to C. pneumoniae, C. psittaci, C. pecorum, C. trachomatis, Mycoplasma pneumoniae, Legionella pneumophila serogroups I-VI, Streptococcus pneumoniae and various respiratory viruses. Twelve of 539 (2.2%) patients had acute C. pneumoniae pneumonia and an additional 32 (5.9%) had possible acute infection. C. pneumoniae was the sole pathogen in 16 of 42 (38.1%) of these patients. The most common copathogens were S. pneumoniae, respiratory syncytial virus and influenza virus type A. C. pneumoniae pneumonia patients were older and more likely to show congestive heart failure compared to bacteraemic S. pneumoniae patients. The latter had a lower mean diastolic blood pressure, a higher white blood cell count and a lower arterial carbon dioxide tension. Two patients had antibody titres suggestive of recent infection with the feline strain of C. psittaci. Although numerically Chlamydia pneumoniae is an important cause of community-acquired pneumonia, no distinctive clinical features associated with this pathogen were detected in the present study. Feline Chlamydia psittaci may cause a few cases of community-acquired pneumonia. Avian Chlamydia psittaci should be considered only if there is a compatible epidemiological history.     

Pyogenic bacterial pneumonia in the acquired immunodeficiency syndrome

Individuals with human immunodeficiency virus (HIV) infection are more susceptible to bacterial infections because of defects in both cellular and humoral immunity. The most common causes of community-acquired pyogenic bacterial pneumonia in HIV-infected patients are Streptococcus pneumoniae and Haemophilus influenzae. The clinical presentation of HIV-infected patients with pyogenic pneumonia does not seem to differ significantly from that of patients without HIV infection. Response to therapy is generally good, and complications relatively few. Prevention of bacterial pneumonia is very important in the care of HIV-infected persons. The pneumococcal vaccine is currently recommended for all HIV-seropositive individuals, although its efficacy is unknown is this setting. Other forms of prevention require further investigation but may prove to be helpful.     

Multicenter screening of Chlamydia pneumoniae pneumonia by ELISA method

We prospectively investigated the etiology of community-acquired pneumonia among adult patients admitted to three general hospitals over one year. Antibody titers to Chlamydia pneumoniae were also measured by ELISA method to investigate the incidence and clinical pictures of C. pneumoniae pneumonia in Japan. Two hundred and fourteen patients were enrolled in the study. Seventeen patients (7.9%) satisfied the criteria for diagnosis of acute infection due to C. pneumoniae by ELISA method. C. pneumoniae was the 3rd leading causative agent following Streptococcus pneumoniae (21.5%) and Haemophilus influenzae (8.4%). Preexisting antibodies were detected in 62.1% of the patients. Most of the patients with C. pneumoniae pneumonia were aged, and had comorbidities of respiratory system. Superinfection with bacterial pneumonia was recognized in some patients. Though there are several problems, ELISA method is thought to be useful to diagnose C. pneumoniae pneumonia, and is suitable for screening tests.     

Clinical analysis of pneumonia in the elderly in a community hospital--comparison of community-acquired pneumonia and nosocomial pneumonia]

We experienced 530 elderly cases with pneumonia among 930 patients with pneumonia in Kawasaki Medical School Kawasaki Hospital between April 1986 and September 1998. Clinical analysis of all these patients and a comparison of one group consisting of 418 patients with community-acquired pneumonia and another group composed of 112 patients with nosocomial pneumonia were performed. In all of the elderly patients with pneumonia, respiratory symptoms and inflammatory findings were less frequent, but were frequent for those in poor general and nutritional condition. The causative microorganism was isolated in 42% of these patients. Streptococcus pneumoniae, MSSA and Klebsiella pneumoniae were frequently isolated from the sputum of the patients with community-acquired pneumonia, while Methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, Methicillin-sensitive Staphylococcus aureus (MSSA) were frequently isolated from that of nosocomial pneumonia patients. Mycoplasma pneumoniae, Chlamydia pneumoniae and some viruses were less frequent for patients in both groups. Although many intravenous antibiotics, such as cephem or carbapenem were administered to patients in both groups, the prognosis was relatively good for those with community acquired pneumonia but was extremely poor for those with nosocomial pneumonia despite mechanical ventilation or steroid pulse therapy for many patients.     

Evaluation of the causative bacteria of pneumonia in the elderly in recent years

A study of 62 cases of elderly pneumonia (EP) in their sixties and eighties with etiologic bacteria confirmed by cultures of sputum, blood or pleural effusion was carried out Greater change of etiologic bacteria of EP in patients of eighties has been found when they were compared with those of sixties. In the group of eighties the incidence of Gram-negative bacilli increased (77%), including pseudomonas aeruginosa (48.39%), Klebsiella pneumoniae (17.35%) and Enteric coli (9.68%), while Staphylococcus aureus accounted only for 16.1%. There were 2 species of Streptococcus pneumoniae; both were mixed with other bacteria in cultures. In patients of eighties the etiologic agents isolated from pneumonia were more resistant to many common antibiotics. The above mentioned results suggest that the diagnosis of etiology of pneumonia in the elderly should be emphasized.