An outbreak of Campylobacter jejuni infection in a neonatal intensive care unit.

During a period of 2 weeks Campylobacter jejuni infection was diagnosed in seven infants in a neonatal intensive care unit. An identical serotype of Camp. jejuni was found in five of the cases.

Soft tissue calcification: a complication of vitamin E injection.

Two cases of gross soft tissue calcification following intramuscular administration of vitamin E in two premature babies are described. The drug was administered for prevention of retinopathy of prematurity. The relation between this complication and both the dosage used and the duration of the treatment is discussed.

Elucidation of the phagocytosis mechanism with the aid of luminous bacteria.

Phagocytosis of the luminous bacterium Vibrio cholerae var. albensis caused a similar decrease both in viable count and in the in-vivo luminescence. These effects of polymorphonuclear neutrophil leukocytes (PMN) were oxygen-dependent processes.

The use of luminous bacteria for determination of phagocytosis.

The existing methods for phagocytosis evaluation are inadequate for assessing all the real events occurring during phagocytosis, or for continuously following the kinetics of the process. Our purpose is to establish the use of luminous bacteria as an object for phagocytosis. The bioluminescence test offers an easy and simple method to determine the kinetics of phagocytosis by following the luminescence of the bacteria.

Determination of serum bactericidal activity with the aid of luminous bacteria.

Nonmarine luminous bacteria belonging to the genus Vibrio cholerae were extremely sensitive to the bactericidal activity of human serum. Luminous bacteria incubated in a medium containing serum showed a decrease in their in vivo luminescence that was directly proportional to the decrease in the viable count and was a function of the serum concentration. Both immunoglobulins and the complement system were required to exert the serum bactericidal activity.

Phagocytosis-induced mutagenesis in bacteria.

Dark mutants of the luminous bacteria Photobacterium fischeri reverted to hereditary stable luminescent forms when incubated with human polymorphonuclear neutrophils (PMN). The maximal mutagenic effect occurred during the first 15 min of phagocytosis, and was dependent on the phagocyte:bacterium ratio as well as on the integrity of the PMN cells. Heat-killed phagocytes or disintegrated phagocytes did not show any mutagenic activity, whereas the supernatant of the phagocytosis reaction exerted mutagenic activity.