Improved semiselective medium for isolation of Legionella pneumophila from contaminated clinical and environmental specimens

Eighteen types of media, all of which used charcoal yeast extract medium as a base, were tested for their ability to support the growth of a stock strain of Legionella pneumophila. Fifteen of these contained antimicrobial agents. Five antibiotic-containing media which performed best in growing the stock strain were then tested for the ability to grow L. pneumophila from clinical respiratory tract specimens. One of the media, BMPA alpha, which contained cefamandole, polymyxin B, anisomycin, an organic buffer, and alpha-ketoglutarate, performed from contaminated clinical specimens and, in conjunction with an acid wash treatment, facilitated recovery of the bacterium from potable water.

Long-term followup of two patients with pulmonary cavitation caused by Legionella pneumophila

Two patients with cavitary pneumonia caused by Legionella pneumophila were followed by several months. Both patients had positive sputum cultures for L. pneumophila; one patient had positive respiratory tract cultures for 18 days after initiation of erythromycin. Slow resolution of the cavities occurred in both patients after 1 to 2 months of antimicrobial therapy.

Legionella longbeachae species nova, another etiologic agent of human pneumonia

A new species of bacteria that is an etiologic agent of human pneumonia has been isolated and characterized. Clinical symptoms of infection with this organism are not readily distinguishable from those caused by Legionella pneumophila infection. The organism was isolated from respiratory tract specimens from four patients. Two cases of infection apparently originated in California and one in Georgia, and a fourth was of unknown geographic origin. The name Legionella longbeachae species nova is proposed for this organism. The type strain of L. longbeachae is Long Beach 4 (= American Type Culture Collection 33462).

Rapid radioimmunoassay diagnosis of Legionnaires' disease: detection and partial characterization of urinary antigen

Urine from nine patients with serogroup 1 Legionnaires' disease, 100 with infected or contaminated urine, 50 with bacteremic infections, 26 with infectious or infiltrative pulmonary diseases, and 65 with miscellaneous infectious or noninfectious illnesses, was examined by radioimmunoassay for the presence of Legionella pneumophila antigen(s). Urine of all nine Legionnaires' disease patients was clearly differentiated from that of the 241 control subjects by the assay. The antigen was detected from 2 to at least 10 days after the initiation of erythromycin therapy. A probable false-positive results occurred in a patient with necrotizing nosocomial pneumonia who died before definitive serologic evaluation for Legionnaires' disease could be completed. The antigen was stable at 100 degrees C for 30 minutes and was not degraded by trypsin. Its elution behavior suggested that its molecular weight is approximately 10 000. The radioimmunoassay appears to be a useful method for rapidly diagnosing serogroup 1 Legionnaires' disease.

Susceptibility of Legionella pneumophila to twenty antimicrobial agents

Thirty-three isolates of Legionella pneumophila, all except one of which were clinical isolates, were tested against 20 antimicrobial agents by using an agar dilution technique. Erythromycin, rifamp]in, and rosaramycin were the most active agents tested. Aminoglycosides, chloramphenicol, and cefoxitin also inhibited the organisms at low concentrations. Other agents, including moxalactam, cefoperazone, and cephalosporins, exhibited moderate to little activity. Tetracycline, doxycycline and minocyeline were apparently inactivated by charcoal-yeast extract medium. There was slight inoculum dependence noted with most of the antimicrobials tested, particularly the beta-lactam agents. There was no consistent difference in susceptibility between Center for Disease Control-supplied stock strains and recent clinical isolates, but there were marked differences with some agents. Susceptibility testing needs to be standardized in view of the influence of inoculum size, strain variation, and the medium used.

Legionnaires' disease: unusual clinical and laboratory features

During a nosocomial epidemic of Legionnaires' disease, clinical and laboratory observations led to the recognition of remarkable aspects in six patients. Features included two episodes of disease, dual or sequential infections with Legionella pneumophila and other pathogens; transient deafness with erythromycin therapy, and Legionnaires' disease with a pleural effusion but no pulmonary infiltrate. Expectorated sputum culture yielded two serogroups of L. pneumophila in one patient. Cultures of transtracheal and endotracheal aspirates and of blood led to the diagnosis, permitted evaluation of confounding potential pathogens, and confirmed Legionnaires' disease in the absence of seroconversion. Although many manifestations of Legionnaires' disease were quite typical in this outbreak, these additional unusual features expand the spectrum and illustrate the value of rapid diagnostic methods.

Immunologic diagnosis of Legionnaires' disease: cross-reactions with anaerobic and microaerophilic organisms and infections caused by them

The hundred twenty-four isolates of anaerobic and microaerophilis organisms were examined with a polyvalent direct immunofluorescent antibody (DFA) reagent directed against Legionella pneumophila, serogroups (SG) I-IV. Three of 53 isolates of Bacteroides fragilis cross-reated with the SG I component of the reagent. Rabbit antisera to three SG I strains of L. pneumophila cross-reacted with these three B. fragilis isolates, and cross-reactivity was not due to preexisting rabbit antibodies; antisera to a fourth SG I strain did not cross-react with these isolates. Indirect fluorescent antibody (IFA) examinations of convalescent-phase sera from eight of 41 patients with B. fragilis group infections showed titers of greater than or equal to 1:128 or a fourfold or greater seroconversion against L. pneumophila, SG I. All eight patients had bacteremia due to B. fragilis, but five B. fragilis isolates available from these patients were DFA-negative. Thus, false-positive reactions may result from DFA as well as IFA examinations of sera from patients with B. fragilis infections.

Legionnaires' disease. Postmortem pathologic findings of 20 cases

From March 1977 to December 1978, postmortem examination was performed at Wadsworth Veterans Administration Medical Center for 20 patients who had had nosocomially acquired Legionnaires' disease. Seventeen patients died during the acute illness due to Legionnaires' disease, and three patients died after clinical resolution of the acute process. The only consistent postmortem findings were limited to the lungs. Confluent bronchopneumonia, and less frequently lobar pneumonia, was present in most cases. Although a spectrum of microscopic pulmonary findings was observed, the characteristic histologic features of acute Legionnaires' disease were an extensive intra-alveolar exudation of macrophages and neutrophils in varying proportions, erythrocytes, and fibrin. Lysis of the inflammatory cells was frequently found. Areas of coagulative necrosis of the lung parenchyma and edematous thickening of the alveolar septa were typically seen. Microscopy of lung tissue from the three patients who died after clinical resolution of the acute process revealed organized pneumonia, with patchy organization of the intra-alveolar exudate and focal obliteration of the alveolar septal framework. Associated postmortem findings were fibrinous endocarditis in one case and hemorrhagic infarction of the adrenal glands in two cases. Electron-microscopic examination of the lungs revealed as many as 23 separate bacillary profiles within a single macrophage. Septate binary fission or spore-like structures were not observed.

Laboratory diagnosis of Legionnaires' disease

Legionnaires' disease was diagnosed in 32 patients with nosocomially acquired pneumonia by using direct immunofluorescence examination of respiratory tract secretions, indirect immunofluorescence determinations of antibody titer, and/or culture of Legionella pneumophila from respiratory tract secretions. Cultures of specimens for Legionella pneumophila were positive for 13 of 21 patients for whom appropriate specimens were submitted. Using a positive culture as a definition of Legionnaires' disease, the sensitivity of direct immunofluorescence examination was 62%; that of indirect immunofluorescence serologic studies, 75%. Using any positive test as a definition of Legionnaires' disease, the sensitivity of direct immunofluorescence examination of respiratory tract secretions was 50%, that of indirect immunofluorescence serologic studies (using all 4 serogroups), 80%; that of culture, 65%. A negative control group of 21 patients without Legionnaires' disease was used to estimate the specificity of the tests. The specificity of direct immunofluorescence examination was 94%; that of indirect immunofluorescence serologic studies, 75%. Culture of specimens was necessary to diagnose some cases of Legionnaires' disease because the other 2 tests were negative. All 3 tests should be performed for optimal sensitivity and specificity.

Prospective comparative study of efficacy and toxicity of netilmicin and amikacin

Eighty patients were treated with either amikacin or netilmicin in a prospective randomized study of serious gram-negative bacillary infections, including 11 due to gentamicin-resistant pathogens. Thirty-six treated with netilmicin and 35 treated with amikacin were evaluable for efficacy or toxicity, or both. The overall groups differed significantly only in age. There were no significant differences in efficacy of the two drugs. There were no statistically significant differences at the 95% level between the netilmicin group and the amikacin group with respect to nephrotoxic reactions (38 versus 28%, respectively) or ototoxic reactions (9 versus 25%, respectively). Further comparative trials of netilmicin and other aminoglycosides appear warranted before it is widely used.

Use of a semiselective medium to culture Legionella pneumophila from contaminated lung specimens

Legionella pneumophila was successfully isolated, using a semiselective medium, from two of three lung specimens heavily contaminated with other organisms. This medium is composed of charcoal yeast extract agar, supplemented with vancomycin and polymyxin B. L. pneumophila was observed at 8 days on plates containing less than or equal to 40 units of polymyxin B and less than or equal to 1 microgram of vancomycin per ml.

Legionnaires' disease. A cause of severe abscess-forming pneumonia

In two previously well nonsmokers fatal pneumonia developed with extensive abscess formation. Legionnaires' bacillus was the only pathogen isolated. These cases indicate that Legionnaires' bacillus is capable of causing extensive necrosis of the lung.

Isolation of Legionella pneumophila from blood

Legionella pneumophila has been isolated, with an in-vitro method, from the blood of a patient with fatal legionnaires' disease.

Four serogroups of Legionnaires' disease bacteria defined by direct immunofluorescence

Thirty-five strains of Legionnaires' disease bacteria were shown to belong in four distinct serologic groups on the basis of findings obtained with direct fluorescent antibody testing. Thirty of the strains were placed in group 1, three in group 2, one in group 3, and one in group 4. Immunoelectrophoretic studies showed both unique and common antigens among the representative strains of the four serogroups.

Isolation of Legionella pneumophila from a transtracheal aspirate

Isolation of Legionella pneumophila from a transtracheal aspirate was achieved by using simple in vitro culture methods. Clinical microbiologists should routinely culture for this organism from appropriate body fluids obtained from normally sterile areas.

Isolation of a new serotype of legionnaires' disease bacterium

A new serotype of the legionnaires' disease bacterium has been isolated. The strain appears to be identical with the Philadelphia strain except for the cell-wall antigens as tested by a direct fluorescent antibody technique. Demonstration of a new serotype brings into question the diagnostic specificity of currently used reference strains.

Infections caused by Klebsiella ozaenae: a changing disease spectrum

A total of 64 isolates of Klebsiella ozaenae were recovered from 36 patients during a 40-month period. Over 7,500 isolates of K. pneumoniae were isolated during the same time period. Before this decade, K. ozaenae was considered to be only a colonizer of the nasopharynx or a putative cause of ozena (atrophic rhinitis). K. ozaenae was recovered most frequently from sputum in mixed culture but was associated with infection in 12 patients (2 with bacteremia, 3 with urinary tract infection, 1 with soft tissue infection, and 6 with mucopurulent nasal discharge). The spectrum of disease caused by this organism is more extensive than has been appreciated previously.

Legionnaires' disease in renal-transplant recipients

Legionnaires' disease is reported in five renal-transplant recipients. All had febrile respiratory illnesses with pulmonary infiltrates and one died. The diagnosis was made on clinical features and by indirect fluorescent antibody titres. Symptoms started after maximum immunosuppressive therapy.