No abstract

Two hundred sixty-six strains of Klebsiella pneumoniae isolated from natural water sources in geographically diverse areas (Florida, Massachusetts, and Oregon) were analyzed to determine the serotype, biochemical, virulence, and antimicrobial susceptibility differences between these natural strains and human Klebsiella isolates. Sixty of 72 defined serotypes were found among 210 typable strains. Geographic patterns were present, but in general were not pronounced among serotypes. Reactions with 28 biochemical tests showed percentage responses which were very similar to the summaries of primarily human Klebsiella isolates (as reported by Edwards and Ewing, 1972) and that represented diverse geographic sampling. Virulence studies in representative strains showed no geographic variability and little difference from comparable hospital patient-obtained isolates. In contrast to human hospital isolates, strains demonstrated 90% or greater susceptibility to all antibiotics except ampicillin and carbenicillin; and in further contrast, there was little multiple antibiotic resistance beyond that with ampicillin and carbenicillin. Klebsiella strains constitute a significant portion of the organisms that cause serious gram-negative infections in humans. These oganisms may be endogenously acquired, as part of the natural host flora, or they may be exogenously acquired within the hospital environment. The Klebsiella which are associated with infections pose therapeutic problems for the physician because of the potential for antimicrobial resistance among these infection-related isolates. A study was undertaken to determine the degree of natural Klebsiella resistance to antibiotics, to assess other characteristics of Klebsiella strains isolated from natural receiving waters in geographically divergent areas of the United States, and to compare these strains with characteristics of human clinical Klebsiella isolates. MATERIALS AND METHODS Organism isolation. Klebsiella strains, as characterized by indole, methyl red, Voges-Proskauer, and citrate biochemical reactions, were isolated from fresh and saline water sources in Oregon (88 strains), Massachusetts (68 strains), and Florida (110 strains). The water source was classified as clean if there was no identifiable source of human contamination, or as

Two hundred sixty-six strains of Klebsiella pneumoniae isolated from natural water sources in geographically diverse areas (Florida, Massachusetts, and Oregon) were analyzed to determine the serotype, biochemical, virulence, and antimicrobial susceptibility differences between these natural strains and human Klebsiella isolates. Sixty of 72 defined serotypes were found among 210 typable strains. Geographic patterns were present, but in general were not pronounced among serotypes. Reactions with 28 biochemical tests showed percentage responses which were very similar to the summaries of primarily human Klebsiella isolates (as reported by Edwards and Ewing, 1972) and that represented diverse geographic sampling. Virulence studies in representative strains showed no geographic variability and little difference from comparable hospital patient-obtained isolates. In contrast to human hospital isolates, strains demonstrated 90% or greater susceptibility to all antibiotics except ampicillin and carbenicillin; and in further contrast, there was little multiple antibiotic resistance beyond that with ampicillin and carbenicillin.