An explosive, common-source outbreak of pneumonia caused by a previously unrecognized bacterium affected primarily persons attending an American Legion convention in Philadelphia in July, 1976. Twenty-nine of 182 cases were fatal. Spread of the bacterium appeared to be air borne. The source of the bacterium was not found, but epidemiologic analysis suggested that exposure may have occurred in the lobby of the headquarters hotel or in the area immediately surrounding the hotel. Person-to-person spread seemed not to have occurred. Many hotel employees appeared to be immune, suggesting that the agent may have been present in the vicinity, perhaps intermittently, for two or more years.

To identify the etiologic agent of Legionnaire's disease, we examined patients' serum and tissue specimens in a search for toxins, bacteria, fungi, chlamydiae, rickettsiae and viruses. From the lungs of four of six patients we isolated a gram-negative, non-acid-fast bacillus in guinea pigs. The bacillus could be transferred to yolk sacs of embryonated eggs. Classification of this organism is incomplete. We used yolk-sac cultures of the bacillus as antigen to survey suspected serum specimens, employing antihuman-globulin fluorescent antibody. When compared to controls, specimens from 101 to 111 patients meeting clinical criteria of Legionnaires' disease showed diagnostic increases in antibody titers. Diagnostic increases were also found in 54 recent sporadic cases of severe pneumonia and, retrospectively, in stored serum from most patients in two other previously unsolved outbreaks of respiratory disease. We conclude that Legionnaires' disease is caused by a gram-negative bacterium that may be responsible for widespread infection.

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Two outbreaks of postoperative wound infections due to organisms of the Mycobacterium fortuitum complex (Mycobacterium chelonei and M. fortuitum) occurred among patients who underwent open-heart surgery. In one hospital, 19 of 80 patients who underwent cardiac surgery within a 10-week period developed sternal infection with M. chelonei. In the second hospital, four of nine patients who underwent cardiac surgery within a two-week period developed sternal incisional infection with M. fortuitum. Although epidemiologic investigations uncovered factors that were significantly associated with the development of infection, the source of the infections could not be determined. The results of numerous cultures were negative, but because the investigations were conducted at least two months after many of the patients had had surgery, the materials in use at the time of the surgery were not available for culture. These results emphasize that physicians should be aware that rapidly growing mycobacteria may produce postoperative wound infections.

Two outbreaks of peritonitis caused by a Mycobacterium chelonei-like organism--a previously unrecognized pathogen--occurred among patients receiving intermittent chronic peritoneal dialysis (CPD). In one center, five of 22 patients who had undergone CPD during a one-month period developed peritonitis caused by an M. chelonei-like organism acquired from a single contaminated automated CPD machine. In a second center, five of eight patients who had received CPD during a several-week period became infected, apparently as a result of cross-infection from contaminated machines. Seven sporadic cases of peritonitis due to an M. chelonei-like organism were also found. M. chelonei-like organisms can survive and proliferate in water and are relatively resistant to formaldehyde. Defects in the design of CPD machines and disinfection procedures were identified that may have permitted M. chelonei-like organisms to survive attempted disinfection.

To determine the risk factors associated with toxic-shock syndrome (TSS) in menstruating women, we conducted a retrospective telephone study of 52 cases and 52 age-matched and sex-matched controls. Fifty-two cases and 44 controls used tampons (P < 0.02). Moreover, in case-control pairs in which both women used tampons, cases were more likely than controls to use tampons throughout menstruation (42 of 44 vs. 34 of 44, respectively; P < 0.05). There were no significant differences in brand of tampon used, degree of absorbency specified on label, frequency of tampon change, type of contraceptive used, frequency of sexual intercourse, or sexual intercourse during menstruation. Fourteen of 44 cases had one or more definite or probable recurrences during a subsequent menstrual period. In a separate study, Staphylococcus aureus was isolated from 62 of 64 women with TSS and from seven of 71 vaginal cultures obtained from healthy controls (P < 0.001).

Suicide and other self-directed violence deaths are likely grossly underestimated, reflecting inappropriate classification of many drug intoxication deaths as accidents or unintentional and heterogeneous ascertainment and coding practices across states. As the tide of prescription and illicit drug-poisoning deaths is rising, public health and research needs would be better satisfied by considering most of these deaths a result of self-intoxication. Epidemiologists and prevention scientists could design better intervention strategies by focusing on premorbid behavior. We propose incorporating deaths from drug self-intoxication and investigations of all poisoning deaths into the National Violent Death Reporting System, which contains misclassified homicides and undetermined intent deaths, to facilitate efforts to comprehend and reverse the surging rate of drug intoxication fatalities.

During July 1978 an outbreak of Legionnaires' disease characterized by high fever, prostration, and pneumonia occurred at an Atlanta, Georgia, country club. All eight cases involved club members whose primary club activity was golfing. The degree of golfing activity during the likely exposure period was a risk factor for acquiring the illness. Legionella pneumophila was isolated from the evaporative condenser within the clubhouse. The fact that the stream of air blowing from the exhaust duct of the evaporative condenser was directed toward a nearby practice green and the 10th and 16th tees supports the hypothesis that this outbreak represents airborne dissemination of L. pneumophila from the evaporative condenser to an outdoor site where susceptible golfers contracted the illness.