TheKlebsiella-Enterobacter-SerratiaDivision

Abstract

Biochemical reactions and capsular typing were used to classify strains of the Klebsiella-Enterobacter-Serratia Group of the family Enterobacteriaceae isolated at Boston City Hospital. Klebsiella pneumoniae accounted for 84% of the 306 strains studied, and 87% of the strains of that species were typable using 72 capsular antiserums; 38 types were found, but type 24 alone accounted for 24% of all the typable strains. Klebsiella pneumoniae types 1, 3, 4 and 5 were recovered most often from the respiratory tract, whereas other types (including type 2 and nontypable strains) were most frequently isolated from urine as Wdre strains of Enterobacter. Susceptibility tests with gentamicin , kanamycin, poiymyxin, colistin'', streptomycin, chloramphenicol and tetracycline were tested as to antibiotic activity. Cephalothin was moderately active against strains of K. pneumoniae but not against those of Enterobacter-Serratia. Increased resistance to antibiotics was associated with: hospital origin of the strains; prior antibiotic therapy; nonrespiratory source; and capsular types, the strains of types 24 being generally more resistant than others.