Comparative features of pneumococcal, mycoplasmal, and Legionnaires' disease pneumonias

Rapid etiological diagnosis of pneumonia in young men

The major findings and conclusions of the present study are: 1. Evidence of the etiology of the pneumonia was established in 86% of 106 young men with pneumonia. Pneumococcus was the most common etiologic agent; it was detected definitely in 30% of the pneumonia patients, and possibly in another 20%, by blood culture, sputum culture, antigen detection, and serological methods. 2. Pneumococcal antigen detection from purulent pretreatment sputum samples was the best rapid diagnostic method for pneumococcus; it was capable of identifying 90% of the pneumococcal pneumonias definite by our criteria, whereas sputum Gram stain was positive in 65% of these. 3. Detection of adenoviral antigens from nasopharyngeal specimens (NPS) by EIA or IF method or adenovirus DNA by HYB method showed good specificity but a somewhat lower sensitivity than did adenovirus isolation from NPS. 4. Adenovirus antigens and DNA can be demonstrated also from sputum specimens. 5. EIA is slightly superior to the CF method in detecting antibody responses to adenovirus, but the detection of different antibody classes offers no additional diagnostic possibilities. 6. Isolation of Mycoplasma pneumoniae from bronchoalveolar fluid in pneumonia patients is a specific and sensitive method in the diagnosis of mycoplasmal pneumonia. 7. It seems possible to differentiate by clinical signs and symptoms and by high CRP (over 85mg/1) and WBC (over 10 x 10(9)/1) values pneumococcal pneumonias from viral, mycoplasmal and mixed pneumonias and from upper respiratory infections. Moderately elevated CRP values were observed in adenoviral (Mean 50 mg/1) and in mycoplasma (mean 59 mg/l) pneumonias, as well as in MRI (mean 44 mg/l).

Bacteremic pneumococcal pneumonia in Sweden: clinical course and outcome and comparison with non-bacteremic pneumococcal and mycoplasmal pneumonias

279 patients with 285 episodes of bacteremic pneumococcal pneumonia (Pnb), treated at the 2 departments for infectious diseases in Stockholm, Sweden, were reviewed retrospectively. Almost half of all episodes were caused by serotypes 3, 9 and 4 (in that order). The overall mortality rate was 7% and as low as 5% if patients with extrapulmonary complications were excluded. As in other studies male sex, alcoholism and absence of leukocytosis on admission to hospital were all associated with a higher mortality rate. However, the prognosis for old patients was much better than in most other studies. This was true also when the infecting strain was of serotype 3. For 89 consecutive patients out of the 279 ones with Pnb the clinical, laboratory and chest X-ray data were compared with those of 44 patients with non-bacteremic pneumococcal pneumonia (Pn) and 27 patients with Mycoplasma pneumoniae pneumonia (MP). Within the pneumococcal group almost all non-bacteremic patients had respiratory tract symptoms compared to less than half of the patients with bacteremic disease. High age, alcoholism, chills, pleuritic chest pain, a leukocyte count of greater than 15 x 10(9)l and an elevated CRP were factors significantly more common among those with pneumococcal pneumonia than among the MP patients. On chest X-ray an alveolar pattern was seen in all but 2 of the totally 133 patients with a pneumococcal pneumonia, but also in half the patients with MP.

Significance of non-pneumophila Legionella species in adult community-acquired and nosocomial pneumonias

The number of different Legionella species is increasing at an impressive rate. In two prospective studies, one involving 110 intensive-care unit (ICU) patients with mainly nosocomial pneumonias and the other 105 patients with community-acquired pneumonias, we investigated the incidence and significance of Legionella pneumophila and non-pneumophila pneumonias on the basis of 17 different main serogroups. In the first study, 14 ICU patients had 15 (13.6%) Legionella pneumonias, which, in 5 cases (33%), were of non-pneumophila etiology. In the second study, 9 patients with community-acquired pneumonias had 10 (9.5%) Legionella pneumonias. Leading this study were 6 L. gormanii infections, followed by 2 L. dumoffii and only 1 L. pneumophila and 1 L. longbeachae pneumonia. Of the total, 22 of 23 patients with Legionnaires' disease suffered from severe basic diseases and complications (acute renal failure, respiratory insufficiency, etc.) predominant among the nosocomial pneumonias. The mortality rate was significant in these patients at 33% (5 patients) in the ICU group and 10% (1 patient) in the group with community-acquired pneumonias. We conclude that non-pneumophila Legionella species should receive more diagnostic and therapeutic consideration in patients with nosocomial or community-acquired pneumonias.

Comparative clinical and laboratory features of legionella with pneumococcal and mycoplasma pneumonias

The clinical and laboratory features of 83 cases of community-acquired pneumococcal pneumonia (PP), 79 cases of legionella pneumonia (LP) and 62 cases of mycoplasma pneumonia (MP) have been compared. No unique features have been found in any group. Patients with MP were younger, were more likely to have had prior antibiotics before hospital referral, had a predominance of upper respiratory tract symptoms, low total white cell counts and lacked features of multisystem involvement. Multisystem features were common in both PP and LP with confusion, high fever, hyponatraemia, hypoalbuminaemia and abnormalities of liver function occurring more often in LP. A high leucocyte count was especially common in PP. Antibiotic therapy in community-acquired pneumonia must remain empirical until a definite microbiological diagnosis is made.

Overwhelming pneumonia

Overwhelming pneumonia may be caused by a large number of different organisms in both immunocompetent and compromised hosts. In this article, the most common etiologies of overwhelming pneumonia are considered from an epidemiologic and clinical point of view.

Antigen detection for the rapid diagnosis of mycoplasma and Legionella pneumonia

Immunologic attempts to detect mycoplasma antigens in fluids of infected patients have been rare and largely unsuccessful. Nucleic acid hybridization procedures appear promising on the basis of successes in detecting mycoplasmal contamination of tissue culture cells; results of attempts to apply these techniques to human infections have not been reported. Antigens can be detected in the urine of about 80% of patients with serogroup 1 Legionella pneumophila pneumonia and of some patients with serogroup 4 Legionella pneumophila and Legionella dumoffii pneumonia. The specificity of these assays is greater than 99%. In a test population in which the prevalence of Legionella pneumophila was 4%, the posterior probabilities of positive and negative results of tests for antigen were 86.5% and 99.3%, respectively. Antigen is detectable within the first 3 days of illness approximately as often as at later periods, and antigen may remain detectable for a few days to 1 yr after successful therapy. Antigen is detectable in serum, but the concentrations are considerably lower than in urine. Combining urinary antigen detection with direct fluorescent antibody examination of secretions increases the rapid diagnostic yield by 10%-20%. Monoclonal antibody studies demonstrate that subgroup specificities are present among the serogroup 1 urinary antigens. Radiometric and enzyme immunoassays detect antigen in equal proportions of patients. Latex agglutination results are positive in about 80% of those cases positive by the other methods.

Community-acquired bronchitis and pneumonia. Presentation, pathogens, and therapy

Community-acquired bronchitis and pneumonia are common conditions that can be approached in a methodical manner. Knowledge of the patient's epidemiologic history, any underlying conditions, and the clinical presentation should allow the physician to make a rational empirical judgment concerning therapy and the need for hospitalization. Most patients with bronchitis and many with pneumonia can be treated as outpatients if the diagnosis is certain and the patient is compliant and is not severely ill. However, if the diagnosis is in doubt or if other issues surface, strong consideration should be given to early hospitalization. All reasonable efforts should be made to identify a specific pathogen, although in many instances the clinician can make valid empirical choices, obviating invasive and potentially dangerous procedures. If the patient has an adverse drug reaction or otherwise responds unsatisfactorily to treatment, more invasive measures may be necessary.

Legionella brain stem encephalopathy and peripheral neuropathy without preceding pneumonia

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Legionella and Legionnaires' disease: a review with emphasis on environmental studies and laboratory diagnosis

Legionella pneumophila and related species are important causes of epidemic bacterial pneumonia and nosocomial infection. This review will discuss this new family of bacteria and the diseases they produce. The classification, general microbiologic characteristics, and ecology of the bacteria will be reviewed and the epidemiology and clinical aspects of the infection will be discussed. More emphasis will be given to issues that are more directly related to laboratory workers and with which the author has had more direct experience: pathology, laboratory diagnosis of human infection, pathogenesis of the infection, and virulence mechanisms of the bacterium. Therapy and prevention of the infection will be discussed more briefly.

Sporadic Legionnaires' disease: clinical observations on 87 nosocomial and community-acquired cases

To add information about sporadic Legionnaires' disease, 87 cases of L. pneumophila pneumonia were reviewed. Twenty cases were nosocomial infections and 67 cases were community-acquired. Most cases (64%) occurred between July and October. The mean age of patients was 51.4 years and males outnumbered females 2.5:1.0. Thirty-one percent of patients were receiving corticosteroid, immunosuppressive, or antineoplastic chemotherapy when illness began. Immunosuppression at onset of illness was more common in nosocomial infections (90%) than in community-acquired infections (14%). Seventy percent of patients had underlying diseases. Malignancies, renal failure, and transplantation were the most common conditions underlying nosocomial infections. Chronic lung disease and malignancies were the most common diseases underlying community-acquired infections. The case-fatality rate in nosocomial infection (70%) was greater than that in community-acquired disease (22%). Clinical, laboratory, and radiologic features of the cases were examined. Illness ranged from mild to severe. Extrapulmonary findings of encephalopathy and renal failure were more common in fatal than in non-fatal cases. Indirect immunofluorescent and microagglutination antibody responses plateaued by the fourth week of illness. Twenty-nine patients died. The case-fatality rate of patients receiving erythromycin (6%) was less than that of patients receiving penicillin (36%), ampicillin (28%), cephalosporin (32%), or aminoglycosides (41%). Despite erythromycin therapy, the case fatality rate for nosocomial L. pneumophilia pneumonia was unacceptably high (25%).

Symposium on infectious complications of neoplastic disease (Part II). Legionnaires' disease. Aspects of nosocomial infection

Tremendous progress has been made recently in characterization of Legionella pneumophila and infections caused by it. Certain areas that are particularly germane to immunosuppressed patients, who are affected more frequently than other patients, and areas that are controversial and merit particular consideration are considered herein. These include pathogenesis and correlation of experimental and clinical evidence, nosocomial outbreaks and almost ubiquitous distribution of L. pneumophila in water despite only a limited number of studies linking the two by aerosols, prevalence and possible reasons for the apparent spotty distribution, protean clinical manifestations, difficulties in diagnosis, certain aspects of therapy, and control by environmental changes.

Comparative radiographic features of community acquired Legionnaires' disease, pneumococcal pneumonia, mycoplasma pneumonia, and psittacosis

The features of the chest radiographs of 49 adults with legionnaires' disease were compared with those of 91 adults with pneumococcal pneumonia (31 of whom had bacteraemia or antigenaemia), 46 with mycoplasma pneumonia, and 10 with psittacosis pneumonia. No distinctive pattern was seen for any group. Homogeneous shadowing was more frequent in legionnaires' disease (40/49 cases) (p less than 0.005), bacteraemic pneumococcal pneumonia (25/31) (p less than 0.01) and non-bacteraemic pneumococcal pneumonia (42/60) (p less than 0.05) than in mycoplasma pneumonia (23/46). Multilobe disease at presentation was commoner in bacteraemic pneumococcal pneumonia (20/31) than in non-bacteraemic pneumococcal pneumonia (15/60) (p less than 0.001) or legionnaires' disease (19/49) (p less than 0.025). In bacteraemic pneumococcal pneumonia multilobe disease at presentation was associated with increased mortality. Pleural effusions and some degree of lung collapse were seen in all groups, although effusions were commoner in bacteraemic pneumococcal pneumonia. Cavitation was unusual. Lymphadenopathy occurred only in mycoplasma pneumonia (10/46). Radiographic deterioration was particularly a feature of legionnaires' disease (30/46) and bacteraemic pneumococcal pneumonia (14/27), and these groups also showed slow radiographic resolution in survivors. Radiographic resolution was fastest with mycoplasma pneumonia; psittacosis and non-bacteraemic pneumococcal pneumonia cleared at an intermediate rate. Residual intrapulmonary streaky opacities remained in over a quarter of survivors from legionnaires' disease (12/42) and bacteraemic pneumococcal pneumonia (5/19).

Coreactivity of Legionella pneumophila immune sera in the Mycoplasma pneumoniae complement fixation test

Sheep and guinea pigs were immunized with cellular and extracellular antigen from Legionella pneumophila bacteria. After immunization, the animals developed immunoglobulin G titers against the immunizing agent. The same sera were also tested in a Mycoplasma pneumoniae complement fixation test. All the preimmunization sera from sheep showed positive M. pneumoniae complement fixation tests of varying titers, with significant antibody rises in two of five sheep as a result of the Legionella immunizations. In contrast to the sheep, all the guinea pigs were negative in the M. pneumoniae complement fixation test, both in their preimmunization sera and after completion of the Legionella immunizations. The results obtained with the sheep sera may be explained as a nonspecific booster effect of Legionella bacteria upon previously elicited immune responses.

[Clinical picture of Legionnaires' disease (author's transl)]

Legionella infections can take the clinical course of a relatively harmless respiratory infection. However, serious, atypical pneumonia is a more frequent manifestation of infection with these pathogens. As yet, six different Legionella species can be identified; Legionella pneumophila appears to be the most common. Legionnaires' pneumonia is being found with increasing regularity during summer and autumn in elderly male patients with previous illnesses. The clinical picture is characterised by viral "prodrome", high fever, a dry cough, breast pain, confusion, diarrhoea, haematuria, moderate leukocytosis with lymphopenia, low concentrations of sodium in the serum and negative results from microbiological analysis of the sputum and pleural exudate. Diagnosis is confirmed culturally, microscopically and serologically; the indirect immunofluorescence test is of particular value for this purpose. Erythromycin alone or in combination with rifampicin is the treatment of choice.

Seroreactivity to Mycoplasma pneumoniae and Legionella pneumophila: lack of a statistically significant relationship

We reviewed antibody titers to Mycoplasma pneumoniae and Legionella pneumophila serogroup I in sera from 1,060 cases of acute respiratory infection to determine whether there was an association in seroreactivity to these organisms. Of the 170 serum pairs with antibodies to L. pneumophila (35 seroconversions and 135 with presumptive titers), 32 (18.8%) demonstrated seroreactivity to M. pneumoniae (17 seroconversions and 15 with presumptive titers). This frequency was not significantly greater than the seroreactivity to M. pneumoniae observed in sera without antibodies to L. pneumophila (17.5%) (0.05 less than P less than 0.10), which included 111 seroconversions and 45 sera with presumptive titers.

Etiologic diagnosis of acute pneumonia in adults: a growing challenge

For most pneumonia patients, an etiologic diagnosis can be established by proper use of noninvasive methods. Cultures of blood and pleural fluid and serologic titers are the most specific. The clinical history is helpful in distinguishing community- from hospital-acquired pneumonia and in identifying patients who are immunosuppressed or aspiration prone. When noninvasive diagnostic means and initial antibiotic therapy fail, the physician must choose between further empiric treatment and an invasive procedure with its attendant risks. For seriously ill and immunosuppressed patients, the need for an etiologic diagnosis is usually sufficient to justify these risks. The need for invasive diagnostic procedures is likely to increase in the future, necessitating greater knowledge of the relative risks and merits of each procedure on the part of all physicians who treat patients with pneumonia.

Opportunistic lung infections in renal transplant patients: a comparison of Pittsburgh pneumonia agent and legionnaires' disease

From July 1977 to January 1980, 5 cases of pneumonia owing to Pittsburgh pneumonia agent and 4 cases owing to Legionella pneumophila occurred in our renal transplant population. Comparison of the clinical manifestations, laboratory features an radiographic changes demonstrated no unique characteristics that allowed differentiation from other bacterial pneumonias. Diagnosis in all cases required histologic or serologic identification of the infecting organism. We herein present our protocol for establishing rapidly the diagnosis of pneumonia in renal transplant patients with emphasis on the use of open lung biopsy.

Legionnaires' disease among pneumonias in Iowa (FY 1972-1978) II. Epidemiologic and clinical features of 30 sporadic cases of L. pneumophila infection

We reviewed retrospectively the clinical records of 30 cases of sporadic Legionella pneumophila infection that occurred in Iowa between FY 1972 and 1978. Cases occurred throughout the year, most between May and December. Twenty-one male patients and 9 female patients ranging in age from 5-80 years were infected. Half the patients smoked or had an underlying illness; five were receiving corticosteroids or immunosuppressive therapy. Occupations and exposures related to hospitals, construction and travel were common; four patients had been exposed to birds. In addition to L. pneumophila infection, six patients had evidence of infection with a viral, mycoplasmal, bacterial, mycobacterial or fungal pathogen; three had had preceding dental infections. Twenty-seven cases were pneumonias visible on radiographs. Fever, cough, chills, myalgia and rales occurred inover half the cases. Headache, gastrointestinal symptoms and encephalopathy also were seen. Upper respiratory symptoms were uncommon. Urinalysis and blood studies often suggested renal and hepatic involvement, but other routine laboratory diagnostic tests were not helpful. All but two patients were hospitalized; seven required intensive care. The median duration of hospitalization was 12 days. Two patients who did not receive erythromycin or tetracycline therapy died.

Legionnaires' disease

Described here is a unique case of Legionnaires' disease in a previously healthy 46 year old man in whom disseminated disease was demonstrated in the kidneys, bone marrow, spleen and multiple peripheral lymph nodes at autopsy. The pathologic distribution of the lesions suggests that dissemination occurred by both hematogenous and lymphatic pathways. Pancytopenia associated with bone marrow destruction and fibrosis suggests that substances toxic to hematopoietic cells were present. It is likely that many of the unusual systemic manifestations of this disease are related to dissemination of the bacterium. The findings presented extend the spectrum of the clinical and pathologic manifestations of Legionnaires' disease from a mild and self-limited illness to a severe and fatal disseminated form of the disease.

Legionnaires' disease in South Australia. Four case reports

Four severe cases of Legionnaires' disease are described. In addition to multilobar pneumonia with respiratory failure, involvement of the central nervous, cardiovascular, renal, hepatic and coagulation systems had occurred. Adult respiratory distress syndrome complicated respiratory management. Early development of acute renal failure was associated with a poor prognosis. Erythromycin was the most commonly used antibiotic. Review of stored pathological material from patients who died from unidentified pneumonias enabled confirmation of the existence of Legionnaires' disease in Australia in 1974.