A Comparative Study of Organisms of the Friedländer and Coli-aerogenes Groups

Potential pathogens in the environment: Klebsiella pneumoniae, a taxonomic and ecological enigma

A nitrogen-deficient medium and m-Endo agar were employed in the isolation of members of the tribe Klebsielleae from surfaces of vegetables and seeds. With m-Endo agar at an incubation temperature of 37 C, nearly 50% of the vegetables and seven out of seven seed samples yielded organisms which biochemically and serologically were identified as Klebsiella pneumoniae, Viable counts were generally in the range of 10(3) cells per g of vegetable peel or seed. Organisms classified as K. pneumoniae exhibited seven different IMViC patterns, with the --++, ++++, and -+++ patterns most common. Seven of the eleven K. pneumoniae serotypes encountered have previously been isolated from human urinary tract and other infections. Fifty percent of the 40 K. pneumoniae examined exhibited positive acetylene-reducing activity, i.e., they possessed the capability for fixing N(2). Vegetables containing K. pneumoniae may constitute a potential reservoir for human nosocomial genitourinary or other infections.

Differentiation of Aerobacter-Klebsiella isolated from sugarcane

Three hundred and eighty-four isolates were obtained in the completed test portion of the most probable number determinations of coliforms in sugarcane sources. Of these isolates, 88% were of the (- - + +) indole, methyl red, Voges-Proskauer, citrate (IMViC) type and were identified as Aerobacter aerogenes according to the protocol of the American Public Health Association (1). Employing 359 of these cultures, a comparative biochemical, serological, and pathogenicity study was carried out with Klebsiella pneumoniae CDC no. 2211-66 type 9. More than 86% of the organisms tested gave biochemical reactions typical of K. pneumoniae. Of the other isolates, 2% were Enterobacter aerogenes, and the remaining 12% were identified as atypical, nonmotile IMViC types. Comparable agglutination titers were also observed between A. aerogenes and the CDC strain of K. pneumoniae when several randomly selected sugarcane strains were reacted with prepared K. pneumoniae whole cell antiserum. Neither the K. pneumoniae reference organism nor selected sugarcane isolates displayed pathogenicity for mice. On the basis of all the analyses performed, it was suggested that such organisms be classified as K. pneumoniae.