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).

Fluorescent-antibody detection of Legionella dumoffii in a fatal case of pneumonia.

Legionella dumoffii organisms were detected in the lung tissue from a patient with a fatal case of pneumonia, the second reported to date. A fluorescent-antibody conjugate specific for the Tex-KL organism isolated in 1979 revealed many L, dumoffii organisms in lung tissue obtained postmortem from this patient.

Epidemiology of pertussis, Atlanta, 1977.

In the period April to October, 1977, an epidemic of pertussis in the outpatient population of a large metropolitan hospital involved 115 cases that were diagnosed by culture or direct fluorescent antibody tests. A study of secondary cases in household contacts showed attack rates of 81% in children under one year of age; attack rates decreased with increasing age to 8% in persons over 20 years of age. Vaccine efficacy was estimated to be 63%. There was no evidence of decreased efficacy with increasing time after vaccination. Fourteen asymptomatic FA-positive individuals were identified; four of these were also culture positive. Four were adults and ten were children. Nine of the ten children had received three or more vaccinations, compared to only 29 of 78 symptomatic children (P = 0.002).

Preservation of nasopharyngeal smears for fluorescent antibody detection of Bordetella pertussis.

Smears from throat and nasal washings seeded with Bordetella pertussis were either treated with aprotinin (a protease inhibitor) or fixed with 1 or 10% Formalin. These smears were stored at 23, 4, and -70 degrees C. Smears were removed and stained with a fluorescent antibody conjugate for B. pertussis at intervals during 22 days of storage. Results indicate that treatment of smears with 4 or 8 U of aprotinin per ml preserved fluorescent antibody staining qualities of B. pertussis for 22 days; fixation with either concentration of Formalin was unsatisfactory.

"Pittsburgh pneumonia agent": a bacterium phenotypically similar to Legionella pneumophila and identical to the TATLOCK bacterium.

The "Pittsburgh pneumonia agent," isolated by Pasculle and co-workers from human lung tissue, has been cultured on artificial media and characterized. The "Pittsburgh" bacterium and the TATLOCK and HEBA bacteria have identical cultural, biochemical, and antigenic characteristics. They also have the same cellular fatty-acid composition, and DNA relatedness indicates that they belong to the same species.

A Legionella-like bacterium related to WIGA in a fatal case of pneumonia.

An unusual bacterium serologically related to a "rickettsia-like agent," designated previously as WIGA, was seen in lung tissue from a patient who died of pneumonia of unknown cause. A fluorescent antibody conjugate prepared with the WIGA organism, isolated in 1959, was used to stain the lung tissue. Enormous numbers of fluorescent bacteria in the lungs of this patient confirm the pathogenicity of this unusual bacterium.

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.

Recognition of a new serogroup of Legionnaires disease bacterium.

A strain of the Legionnaires disease bacterium (LDB) that was isolated by Joseph E. McDade from a postmortem lung specimen of a patient with fatal atypical pneumonia at the Veterans Administration Hospital in Togus, Maine was serologically different from 16 other strains of LDB that had been isolated previously from patients in other geographic locations. The serological differences of the Togus isolate were shown in results of direct and indirect fluorescent antibody staining and of immunoelectrophoresis with soluble antigen extracts. Seroconversion for the Togus strain of LDB in acute- and convalescent-phase sera from a second patient with atypical pneumonia at the Veterans Administration Hospital in Togus indicated that this patient had been infected with an LDB that was serologically similar or identical to the Togus isolate. The Togus serogroup of LDB should be considered when performing serological tests for Legionnaires disease.

Detection of Legionnaires disease bacteria by direct immunofluorescent staining.

Antisera and fluorescein isothiocyanate conjugates prepared for five strains of the Legionnaires bacteria were tested in both homologous and heterologous staining reactions with 10 isolates of the organism from patients in seven geographic areas. The strains were related but not identical as judged by the results of direct immunofluorescence staining. The conjugates were successfully used to detect Legionnaires disease bacteria in Formalin-fixed lung scrapings, in histological sections, and in fresh lung tissue obtained at biopsy or autopsy. In addition, the labeled antibodies are valuable for staining suspected cultures of the bacterium and for searching for the source of these organisms in soil, water, and other environmental niches. The reagents are highly specific for detecting the Legionnaires organism in clinical specimens.

Optimum immunization of rabbits for Streptococcus mutans antiserum and conjugate production and studies of batch immunoabsorption methods.

By far, the most significant rises in titers were seen with the immunization protocol used in series 6. Conjugates prepared from bleedings on the 33rd day produced exceptionally high titers for type b S mutans, and reasonably high titers for type a were obtained in a short time. A concentrated antigen with Formalin (13.4 ml) was given during a ten-day period followed by a two-week rest period, after which booster doses of either antigen with Formalin or live antigen were given (Fig 1). Based on evaluation of the immunization protocol just described, series 6 resulted in the highest titered reagents, but the data are insufficient to permit recommending that particular schedule without limitations. Our experience in the use of live antigens of S mutans for immunization is limited in that only types b, c, and e have been used in this way. The rabbits survived these injections, but the pathogenicity of other strains and other serotypes has not been determined. In addition, protocols including combined injections of killed and living organisms should be tested further for possible improvement in antibody production. In view of these considerations, our recommendations for production of high titered antiserums for S mutans in rabbits are as follows: -Take a preimmunization bleeding from each rabbit and screen by indirect FA tests with the antigens to be used. -Inject heavy concentrations (40 IU/ml) of Formalin-killed cells, intravenously. -Inject for eight to ten consecutive days, giving increasing doses of antigen ranging from 0.2 to 5.0 ml for a total of 12 to 15 ml. -Rest the rabbits for one week. If you are monitoring the progress of immunization, bleed the rabbits before giving booster injections. -Give booster injections on four consecutive days, giving 0.25, 0.5, 1.0, and 1.5 ml of live antigen that has been washed one time to remove traces of media and adjusted to a concentration of 40 IU/ml. If live antigen is not used, continue to give booster injections with killed antigen, injecting 2.0 ml on each of three consecutive days. -Rest the rabbits for one week and take sufficient blood to produce the trial reagents needed, or exsaguinate the rabbits. Absorption of type a conjugates resulted in the total loss of titer for type a cells. The cross-reactions with type b conjugate were easily eliminated by dilution, with the exception of the cross-reaction with S sanguis JC-43. Bratthall's absorption method eliminated all cross-reactions of the type b conjugate. Absorption of type c conjugate successfully removed the cross-reaction with type e cells; however, the loss of homologous type c titer was so great that this absorption is of limited value. High-titered conjugates for types d and e have been obtained by using batch absorption procedures.