Fifty years of dysentery research at the Pécs University.

Károly Rauss was appointed as head of the Department of Public Health of the Elisabeth University of Pécs in 1946, Professor Rauss's carrier had started working with Professor Hugó Preisz in Budapest. During his residency years he was already appointed to the Department of Bacteriology chaired by Lovrekovics at the National Institute of Public Health. In this institution--as in all organizations affiliated with the Rockefeller Institute--the state of art diagnostic work together with research focusing on problems derived from everyday medical and public health practice was considered as to be of primary importance.

Biofilms produced by Pseudomonas aeruginosa and by Staphylococcus aureus on model medical devices.

Polyethylene, teflon, tygon, polypropylene, silicon rubber, and rubber tubes or rings contaminated with Pseudomonas aeruginosa or Staphylococcus aureus were implanted subcutaneously into mice. After 5 days the colony forming units developing on, and attaching to them were determined. The highest numbers of bacteria were observed on rubber and silicon rubber, polyethylene was next in order, while significantly lower values were obtained on teflon and on tygon and polypropylene.

A model for testing drug susceptibility of Pseudomonas aeruginosa and Staphylococcus aureus grown in biofilms on medical devices.

UV-sterilized polyethylene rings infected with Pseudomonas aeruginosa or with Staphylococcus aureus were implanted into artificial wounds of mice. During 5 days incubation biofilm was formed on the plastic surfaces. To determine the Minimal Bactericidal Dose on sessile bacteria, rings with biofilm were removed and incubated in Luria broth containing serial dilutions of different antibiotics.

Effectiveness of antibiotics on the autochthonous Escherichia coli of mice in the intestinal biofilm versus its planktonic phase.

The effectiveness of antibiotics was tested on the autochthonous Escherichia coli in biofilm mode of growth in large bowel pieces as well as on the predominant faecal E. coli isolated from the same SPF mice in planktonic phase of growth. Aminoglycoside antibiotics, chloramphenicol, oxytetracycline, erythromycin and lincomycin-clindamycin treatment had a very limited effect in the intestinal biofilm.

[Effect of antibiotics on autochtonous intestinal E. coli population in SPF mice and on planktonic phase isolates].

Representatives of different groups of antibiotics were tested on the autochtonous Escherichia coli of mice being in biofilm mode of growth, as well as on their isolates in planktonic phase. Aminoglycoside antibiotics, chloramphenicol, oxytetracycline, erythromycin, lincomycin-clindamycin, and polymyxins showed a very reduced effectivity on Escherichia coli embedded in the biofilm matrix. On the other hand, beta-lactam antibiotics were equally effective both for sessile and planktonic bacteria.