Electron Microscopy of Tissue Culture Cells Infected withBrucella abortus

Abstract

Thin sections of hamster kidney tissue cultures were examined by electron microscopy over a 7-day period after infection with Brucella abortus 3183. Numerous bacteria and structures resembling L-forms were present both intracellularly and extracellularly after the first 24 hr of infection. Most intracellular microorganisms were enclosed by a cytoplasmic membrane, but in a few instances no limiting membrane was detected. After 4 to 7 days, fewer microorganisms were present, and most normal-appearing bacteria were intracellular, particularly in antibiotictreated cultures. Structures typical of Brucella L-forms were extracellular at the latter time intervals. Several structures were observed in cells from infected cultures whose relationship to the infecting organisms is not known. These consisted of various membranous structures within cytoplasmic vacuoles, myelin-like structures surrounding occasional intracellular organisms, and small bodies present within vacuoles and extracellularly. The latter structures observed throughout the experimental period appeared to occur infection increased. more frequently as the duration of the

Demonstration of the Phenomena of Microbial Persistence and Reversion with Bacterial L-Forms in Human Embryonic Kidney Cells

“…In our laboratory, specific fluorescence of transitional-phase variants could be demonstrated for as long as 237 days postinfection in rats kept on penicillin therapy (7). Tissue culture studies of Hatten et al (11,12) and Schmitt-Slomska et al (17) suggest that L-forms can persist within cells for various periods of time. These experimental findings, coupled with an ever-increasing number of welldocumented clinical case reports of isolation of cell wall-deficient variants in cases of persistent and recurrent bacterial infection, dictate the necessity for critical assessment of the role of the L-form in persistence and relapse of infectious disease (6,9).…”

Cytological changes related toBrucella canis variants uptake in vitro

“…Tissue culture studies on other brucellae indicate different degrees of virulence. This fact has been demonstrated in chick embryo fibroblasts (Holland and Pickett, 1956) and guinea pig or mouse monocytes (Braun et al, 1958;Holland and Pickett, 1958); HeLa Cells (Shepard, 1959); Brucella abortus (Hatten et al, 1971). Brucella canis is the most recent member of the genus Brucella.…”