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Biomedical subjects

H R Elston

Publications and source records attributed to H R Elston.

At least 19 recordsLinked to original sources

Arm abscesses caused by Clostridium botulinum.

Wound botulism is an uncommon disorder that continues to be rarely reported in the United States. A 34-year-old intravenous heroin user was admitted to the Loma Linda, Calif., Veterans Administration hospital with multiple abscesses on his forearms. His clinical course was compatible with botulism, and his culture and serum were positive for Clostridium botulinum toxin type A. Early culture and/or serum identification can lead to prompt diagnosis, treatment, and improvement in the morbidity and mortality rates of this disease.

Abscess↗

Evaluation of isolator system and large-volume centrifugation method for culturing body fluids.

The Isolator system was compared with the large-volume centrifugation method for processing and recovering organisms from body fluids other than blood, cerebrospinal fluid, and urine. A total of 155 body fluid samples were processed for the recovery of clinically significant organisms. Of the 55 positive cultures, Isolator detected 94% and the large-volume centrifugation method detected 64%. The time necessary to indicate positivity was not significantly different in the two methods; however, in five cases, the Isolator system yielded clinically significant organisms 24 h sooner than the conventional method. The Isolator system was found to be a more sensitive alternative than the conventional large-volume centrifugation method.

Bacteria↗

Multi-biochemical test system for distinguishing enteric and other gram-negative bacilli.

A multi-biochemical test system consisting of nine tests, entitled Enterotube, was evaluated in parallel with conventional tests to determine its value in the identification of enteric and certain other gram-negative bacilli. The 242 bacterial strains studied were from a variety of pathological specimens and from our culture collection. When the results with individual tests represented in both test systems were compared, no discrepancies were noted in the indole test, and one discrepancy was recorded for dextrose. In 7 of 242 hydrogen sulfide tests, 3 of 242 phenylalanine tests, 22 of 242 urease tests, 15 of 242 dulcitol tests, 12 of 242 lactose tests, 27 of 217 lysine decarboxylase tests, and 5 of 242 citrate tests, the Enterotube results were contrary to those obtained with conventional methods. The lysine decarboxylase test in the Enterotube posed a problem of interpretation and readability and is not an acceptable alternative to the conventional methods. Fifteen of the strains studied were incorrectly identified by the Enterotube system and four could not be differentiated from other closely related strains. Salmonella could be identified as to group, whereas Shigella strains were frequently misidentified as Escherichia. The Enterotube method is simple and convenient, and all media are inoculated at once from a single colony.

Agar↗

Lysine decarboxylase activity in broth and agar media.

Four lysine decarboxylase media were studied by testing them with 305 Enterobacteriaceae and 42 nonfermenting bacilli. A comparison was made between lysine decarboxylase broth medium (Moeller base) and Johnson's semisolid agar without lactose and Bachrach's broth medium and lysine-agar slants which contain lactose. The nonlactose media, lysine decarboxylase broth and the semisolid medium of Johnson, were the best media for use with all of the bacteria studied. The exclusion of lactose from lysine decarboxylase medium seems desirable to extend the usefulness of this medium among members of the Enterobacteriaceae. When the results with lysine decarboxylase broth and Johnson's semisolid medium without lactose were compared, a 6% difference existed between the results obtained with lysine decarboxylase broth and Johnson's semisolid agar. When the results with Bachrach's broth and lysine-agar slants with lactose were compared, a 1% difference existed between Bachrach's broth and the agar slant method. At times, reading and interpretation were difficult because of intermediate degrees of color change. The inability of Pseudomonas aeruginosa or Herellea to utilize glucose under the anaerobic condition of the medium makes the lysine decarboxylase test an undesirable procedure for these organisms. Of the four test media used, the lysine-lactose-agar slants seemed to be the least desirable because of the more frequent occurrence of indistinct color reactions and shifts in color.

Agar↗

Further use of deoxyribonuclease in a screening test for Serratia.

The deoxyribonuclease (DNase) test is useful in classifying Serratia bacilli and in differentiating it from the Hafnia group, E. cloacae, and E. liquefaciens. It is recommended as a differential test in enteric bacteriology because of its specificity, the convenience of its use, and the rapidity with which it can be performed.

Bacteriological Techniques↗