No abstract

The lesions produced by six Candida species on the chorioallantoic membrane (CAM) of the developing chick are described and compared. It is suggested that CAM inoculation be used as a pathogenicity test for Candida species.

Legionella pneumophila continues to play a role in both community- and nosocomially-acquired pneumonia. We investigated the ability of L pneumophila to adhere to various types of materials such as those found in the hospital air-cooling and portable water distribution systems. Through the use of a unique sampling apparatus, we were able to regularly acquire planktonic and sessile samples and determine the numbers of bacteria present in both populations, in vitro and in situ. Portions of these apparatuses could be aseptically removed for examination by scanning electron microscopy, or for the determination of the number of viable adherent L pneumophila. The number of bacteria present in each sample was determined by direct plate count, with presumptive L pneumophila colonies being positively identified by direct fluorescent antibody staining techniques. The results demonstrated that not only are legionellae capable of colonizing various metallic and nonmetallic surfaces but that they are preferentially found on surfaces. Surface-adherent bacteria may play a profound role as a reservoir of these potential pathogens in aquatic environments. Furthermore, these results suggest that any comprehensive legionella monitoring program must include not only water samples but also an examination of the adherent populations.

Outbreaks of Escherichia coli O157:H7 have been attributed to meat or meat products, particularly ground meat, and to unpasteurized dairy products. However, the risk factors for sporadic cases have not been clearly delineated. Study data were collected by using a self-administered dietary and historical questionnaire on all patients whose history included bloody diarrhea and who attended one of the participating emergency departments. Designation as "case" or "control" occurred after stool culture results were known, eliminating the possibility for recall bias common to this type of study. Cases (E. coli O157:H7-positive) were further matched with one diarrheal and one healthy community control, and more detailed information on food preparation practices and other data were then taken. Of 266 presentations of bloody diarrhea, 103 (38.7%) were due to E. coli O157:H7. Unmatched analyses with bloody diarrheal controls revealed a seemingly lower risk for E. coli O157:H7 infection in fast food restaurant patrons. No increased risk could be detected for ground meat consumption despite adequate study power, although an association between ingestion of undercooked meat and infection (odds ratio = 3.5, P less than .05) was found when community controls were used. Proper food cooking (and handling) rather than the avoidance of particular food products is the preventive measure of choice.

Legionella pneumophila continues to play a role in both community- and nosocomially-acquired pneumonia. We investigated the ability of L pneumophila to adhere to various types of materials such as those found in the hospital air-cooling and portable water distribution systems. Through the use of a unique sampling apparatus, we were able to regularly acquire planktonic and sessile samples and determine the numbers of bacteria present in both populations, in vitro and in situ. Portions of these apparatuses could be aseptically removed for examination by scanning electron microscopy, or for the determination of the number of viable adherent L pneumophila. The number of bacteria present in each sample was determined by direct plate count, with presumptive L pneumophila colonies being positively identified by direct fluorescent antibody staining techniques. The results demonstrated that not only are legionellae capable of colonizing various metallic and nonmetallic surfaces but that they are preferentially found on surfaces. Surface-adherent bacteria may play a profound role as a reservoir of these potential pathogens in aquatic environments. Furthermore, these results suggest that any comprehensive legionella monitoring program must include not only water samples but also an examination of the adherent populations.