A Study of Features used in the Diagnosis of Pseudomonas aeruginosa

Abstract

SUMMARYThirty-three strains of Pseudomoizas aeruginosa, previously described as a species group by a quantitative study, were subjected to an extended schedule of tests used in bacterial classification and identification. Adansonian analysis by electronic computer confirmed previous results, indicating that the 33 strains should be treated as a species group. The 172 features coded for each strain were analysed by computer, yielding a ' probability of occurrence ' of each feature within the species, P. aeruginosa.This output was then used to select features appropriate for diagnostic purposes. From the analyses it was also possible to measure the sensitivity of several methods for determining the presence or absence of characteristics such as pigment production and oxidation of gluconate to ketogluconate. The general applicability of the use of the computer to cooperative pooling of data by bacteriologists is discussed.

Taxonomic Studies of Red Halophilic Bacteria

“…The combined data for these organisms and the halophiles, when computed and analyzed, revealed linkage s values of about 40%, much lower similarity values than would be expected if strong relationships between the groups were present. On the basis 8. Similarity matrix of merged data sets for halophilic bacteria, including laboratory culture collection strains and recent isolates from a solar salt facility.…”

“…The modified medium provided more rapid growth and longer viability of the freshly isolated halophiles. Thus, cultures of these strains were maintained on the following medium: yeast extract (Yeast Products), 1.0 8.0 f 0.1. The solid form of the medium contained 2% (wt/vol) agar (Difco).…”

Identification of Bacteria by Computer: Identification of Reference Strains

“…(Rhodes, 1959;Hugh & Ryschenkow, 1961 ;Hugh & Leifson, 1963;Colwell, 1964, Wahba & Darrell, 1965Redfearn, Palleroni & Stanier, 1966;Stanier, Palleroni & Doudoroff, 1966;Weaver, 1967;Lapage, Hill & Reeve, 1968.) Pseudomonas aeruginosa, P. jluorescens, P. mallei, P. maltophilia and P. pseudomallei were included as separate taxa.…”

Numerical Taxonomy of the Flexibacteria

“…Eighty-two features were coded for the 55 strains, and established procedures were used for a preliminary analysis by high-speed computer (Colwell & Liston, 1961;Colwell, 1964). By the 'highest link' sorting (Sokal & Sneath, 1963), three major clusters were noted, with all strains clustering at levels of > 65 yo S.…”

“…During the course of the study a series of programmes was used. Programmes GTP-I to GTP-5 (GTP = Georgetown Taxonomy Programme) were developed for the IBM 1620 and the IBM 360/40 computer systems from programmes written during the earlier work (Colwell & Liston, 1961 ;Colwell, 1964). Essentially, these programmes provide a full S value matrix (GTP-I), a modified link sort and clustering at decrements of similarity values (GTP-2) (R. R. Colwell, to be published), feature frequency sort (GTP-3) (Colwell, I a master programme for the IBM Model 360/40 System.…”