title: [The growth curves of enterobacteriaceae and the estimation of L-forms under the influence of cephalosporin antibiotics].
abstract: The antibacterial effectiveness of cephalothin, cefazolin, cephacetrile and cephradine was investigated on growing cultures of Klebsiella pneumoniae recording the growth curves with a biophotometer. Thereby cefazolin has a greater antibacterial activity than the other cephalosporins. By raising the dose to 100 microgram/ml after initial bactericidal effect a second growth phase was observed. Phase microscopic observation showed that this was caused by an increasing number of L-forms. This phenomenon could be observed with two other strains and seems to be a strain-specific characteristic. It occurs only using cephalosporins and isotonic nutrient media. The medical importance of the described ability of some bacteria as a factor of pathogenicity is discussed.
mesh_terms: D002437:Cefazolin / Q000494:pharmacology; D002505:Cephacetrile / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology*; D002512:Cephalothin / Q000494:pharmacology; D002515:Cephradine / Q000494:pharmacology; D004755:Enterobacteriaceae / Q000187:drug effects / Q000254:growth & development*; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000254:growth & development; D007740:L Forms / Q000254:growth & development*
chemical_list: D002511:Cephalosporins; D002515:Cephradine; D002505:Cephacetrile; D002437:Cefazolin; D002512:Cephalothin