A comparison of the properties of Klebsiella strains isolated from different sources

KLEBSIELLAS are often found in the human bowel and in a variety of environ-mental situations, such as soil, vegetation and water (Duncan and Razzell, 1972; Knittel, 1975). Over the last two decades klebsiellas have become important opportunistic pathogens in hospital patients (Price and Sleigh, 1970; Curie et al., 1978) and have been frequently associated with animal diseases such as bovine mastitis (Braman et al., 1973). Despite the availability of good typing methods, such as capsular serotyp-ing and bacteriocine typing, the epidemiology of klebsiella infections is not fully understood, and little is known of the significance of environmentally derived strains in causing infections in hospital patients. Some previous investi-gations suggested that klebsiellas isolated from human and animal infections are phenotypically indistinguishable from environmental strains (Brown and Seidler, 1973; Dufour and Cabelli, 1976), but DNA-reassociation studies indicated that environmentally derived strains are genetically more diverse than strains of clinical origin (Seidler, Knittel and Brown, 1975). Mor