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

Abstract

Although haemolysin production in Klebsiella is a rare trait, cell lysates of about 59% clinical and 9.5% food-origin isolates were found haemolytic to guinea pig red blood cells (RBCs). Of the 38 pathogenic and 170 non-pathogenic strains, preparations of 29 (76.3%) and 1 (0.59%) strains, respectively, were haemolytic. Among 6 types of RBCs, viz. guinea pig, human (O, A and B groups), calf and sheep RBCs; guinea pig RBCs were haemolysed by all the 30, while sheep RBCs by 16 and others by only 4 haemolytic test preparations. Klebsiella haemolysins appeared to be intracellular or cell-wall associated since only 4 strains could release haemolysins extracellularly to yield positive results on blood agar, while cell lysate of 30 strains possessed haemolytic potential. The study concludes expression of different types of haemolysins by different strains of Klebsiella either as intracellular, cell-wall associated or released extracetlularly into growth medium.