Virulence and Morphological Characteristics of Mammalian Tubercle Bacilli

نویسندگان

  • Gardner Middlebrook
  • René J. Dubos
  • Cynthia Pierce
چکیده

Experimental infection of the mouse can be used for the determination of virulence of cultures of mammalian tubercle bacilli. The relative virulence of such cultures for the mouse is approximately the same as for the guinea pig. Cultures of virulent and avirulent variants of mammalian tubercle bacilli grown in the depth of Tween 80-albumin liquid medium, on the surface of solid agar modifications of this medium, and on the surface of a liquid modification of this medium exhibit consistent morphological differences. All virulent cultures tend to form microscopically demonstrable serpentine cords of varying thickness and length consisting of highly acid-fast bacilli oriented in parallel along the long axis of the cord. The formation of cords appears to be an important factor in conditioning the ability of cultures to spread on the surface of liquid and solid media. It can be inhibited by the addition to the medium of the surface-active water-dispersible oleic acid ester, Tween 80. Avirulent variant bacilli grow in a more or less non-oriented fashion. They have never been observed to form cords under any condition of growth and are much less acid-fast than the virulent cultures when grown in Tween-albumin medium. Two strains of mammalian tubercle bacilli which are intermediate in degree of virulence between the fully virulent and the avirulent variants also exhibit intermediate morphological characteristics.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

THE COLONY MORPHOLOGY OF TUBERCLE BACILLI I. TH~ P~sm~cE oF SMOOTH COLONIES IN STRAndS RECENTLY ISOLATED FROM SOURCES OTHER THAN SPUTUM BY

Variations in the colony morphology of pathogenic bacteria were observed many years ago, but it was not until the work of Arkwright (1, 3, 8), De Kruif (2, 4, 5), and Northrop and De Kruif (6, 7) that the significance of these variations began to be apparent. Since then, the chemo-immunological studies of Avery and his associates (9-14) have demonstrated the urgent need of a dearer understandin...

متن کامل

Specific Tuberculosis Immunity During Infection *

The variegated picture of tuiberculous infection, both spontaneous in man and experimentally induced in animals, has puzzled students and led to most complicated explanations. Most of the earlier experimental studies were handicapped by the lack of two fundamentals which now appear so essential to a solution. One of these was the primary lack of information on the tubercle bacillus and its viru...

متن کامل

Growth characteristics of recent sputum isolates of Mycobacterium tuberculosis in guinea pigs infected by the respiratory route.

The consideration of virulence must distinguish between infectivity and the ability to cause progressive disease once the infection is established. Several investigators have reported the presence of naturally occurring isolates which differ in virulence for guinea pigs. Isolates from south India which differed with respect to gross disease and number of bacilli recovered from spleen after an i...

متن کامل

The Effect of Wetting Agents on the Growth of Tubercle Bacilli

Tween 80 and Triton A20 are two water-dispersible, non-ionic, surface-active agents which favor dispersed growth of tubercle bacilli in aqueous media probably by wetting the bacterial surface. Tween 80 is a polyoxyethylene ester of sorbitan monooleate and is liable to enzymatic hydrolysis by lipases. Triton A20 in an arylalkyl polyether of phenol which appears resistant to the known enzymes of ...

متن کامل

Bactericidal action of oleic acid for tubercle bacilli. II. Morphological response.

In the previous report (Minami, 1957), the bactericidal action of oleic acid on tubercle bacilli was studied, and it was concluded that some particular portion of the cell's surface structure was concerned with this action. In the present paper, the electron microscopic studies were carried out to look for a morphological base for the bactericidal action of oleic and other homologous fatty acid...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • The Journal of Experimental Medicine

دوره 86  شماره 

صفحات  -

تاریخ انتشار 1947