Haemolytic pattern of pathogenic and non-pathogenic Klebsiella isolated from foods and clinical cases

Although haemolysin production in Klebsiella is a rare trait, cell lysates of about 59% clinical and 9.5% food-origin isolates were found haemolytic t o guinea pig red blood cells (RBCs), Of the 38 pathogenic and 170 non-patho genic strains, preparations of 29 (76.3%) and 1 (0.59%) strains, respective ly, were haemolytic. Among 6 types of RBCs, tit. guinea pig, human (O, A an d B groups), calf and sheep RBCs; guinea pig RBC's were haemolysed by all t he 30, while sheep RBCs by 16 and others by only 4 haemolytic test preparat ions. Klebsiella haemolysins appeared to be intracellular or cell-wall asso ciated since only 4 strains could release haemolysins extracellularly to yi eld positive results on blood agar, while cell lysate of 30 strains possess ed haemolytic potential. The study concludes expression of different types of haemolysins by different strains of Klebsiella, either as intracellular, cell-wall associated or released extracellularly into growth medium.