Antagonism of streptomycin activity by culture filtrates of Pseudononas aerugino8a was first reported by Sureau, Arquie, Boyer & Saviard (1948). The factor responsible for the antagonism was isolated (Lightbown, 1954) and was shown by Cornforth & James (1954, 1956) to be a mixture of 2-alkyl-4-hydroxyquinoline N-oxides. The present paper describes an investigation of some of the biological properties of these compounds; part of this work has already been briefly reported (Lightbown & Jackson, 1954; Jackson & Lightbown, 1955). METHODS AND MATERIALS Assay of dihydrostreptomycin antagonist activity. A modified cup-plate diffusion method (Lightbown, 1954) was employed. Cups containing the solutions of the quino

It is proposed that the facultatively anaerobic, gram-neptive organism described by Eiken (1958) and named by him Bacteroides corrodens be transferred to a new genus, which the authors name Eikenella. Organisms of this kind form a fairly homogeneous group and differ in important respects from the generally accepted Bacteroides species and from the members of the currently recognized genera of the family Brucellaceae, wherein the genus Eikenella is placed. An up-dated description of the type species, E. corrodens (Eiken) comb. n. (basionym: B. corrodens Eiken 1958), is given. The type strain of this species, previously designated by Henriksen, is Henriksen's strain 333/54-5 5 (ATCC 23834; NCTC 10596), one of the strains originally studied by Eiken.Certain gram-negative "corroding bacilli" have been subjected to detailed investigation during the past few years (2, 5 , 6), and they appear not t o fit easily into any of the currently recognized genera. Organisms of this type were examined by Eiken ( l ) , who placed them in the genus Bacteroides, under the name B. corrodens, because most of the strains with which he worked either were anaerobic or adapted to aerobic growth only after a number of subcultures. More recent work (6) has shown that the aerobic growth of these organisms may be dependent on the constitution of the medium, particularly on the hemin content. Moreover, the moles per cent guanine plus cytosine (GC) content of the deoxyribonucleic acid (DNA) of all strains tested lies in the 57 to 58 range, and this is widely different from the value for the accepted Bacteroides species. Prkvot (9), who does not accept the validity of the generic name Bacteroides but uses the name Ristella, states that members of the genus have an adenine plus thymine t o GC ratio of 1.4, which is equivalent to a GC content of 41%. Similar values for members of the genus Bacteroides have been quoted by Hill (4). Strains of B. fragilis (42.2%) and B. melaninogenicus (41%) that we have examined gave values close to this figure.The purpose of this paper is t o designate a new genus t o contain the facultatively anaerobic strains of the type t o which Eiken gave the name B. corrodens.

The name Bacteroides ureolyticus is proposed for a species to accommodate strains of gram-negative, urease-positive, anaerobic, corroding rods previously incorrectly referred to as Bacteroides corrodens. The organisms are catalase negative and reduce nitrate. In peptone-yeast-glucose medium, growth is enhanced by the addition of fumarate and formate, and succinate is the major end product. Conventional carbohydrate fermentation tests are negative. The oxidase test is positive and is markedly inhibited by azide. Absorption bands of reduced cytochromes are seen by visual spectroscopy at 550 nm (cytochrome c) and 555-560 nm (b-type cytochrome); no cytochrome a band was detected. Most strains hydrolyze gelatin and casein. Strains with very weak proteolytic activity are also encountered. The cells are nonflagellated but may show "twitching motility." Electron micrographs of five of seven strains reveal polar pili. Strains that lack pili do not produce spreading colonies or show twitching motility. The guanine-plus-cytosine content of the deoxyribonucleic acid is in the range of 28.0 to 30.0 mol%. Strain NCTC 10941 is designated as the type strain.Eiken (2) applied the name Bacteroides corrodens to certain gram-negative rods that formed "corroding" colonies on agar media and that were considered to be anaerobes. It has since become clear that the Eiken collection contained organisms of several different kinds. Some of the strains, including that later designated by Henriksen as the type strain (4), were found to be facultative anaerobes. Three of Eiken's anaerobic strains were later found by Henrichsen (3) to have polar flagella. Nonflagellated anaerobic strains, corresponding in many respects to Eiken's description of B. corrodens, have since been studied in detail by Khairat (8) and by Jackson et al. (7). Organisms of this type are now commonly referred to as B. corrodens, and we reported in an earlier publication (6) that these anaerobic strains can be clearly distinguished from the facultative organisms, which we placed in a new genus, Eikenella. The facultatively anaerobic Eikenella organisms have a deoxyribonucleic acid (DNA) guanine-plus-cytosine (G+C) content of 56 to 58 mol% and do not produce urease, whereas the anaerobic strains have a DNA G+C content of 28 to 30 mol% and are urease positive. It is our purpose in this paper to refer to some instances of possible confusion in the recent literature on these organisms and to propose a new specific name for the anaerobic, urease-positive organisms that up to now have been called B. corrodens. MATERIALS AND METHODSBacterial strains. Strain NCTC 10941 was originally isolated from amniotic fluid at the Misericordia Hospital, Edmonton, Alberta, Canada, and was referred to us for identification by J. H. Stirrat. Strains UAH 1 (from an infected face lesion) and UAH 2 (from an infected heel) were isolated in our diagnostic service at the University of Alberta Hospital. Strain B 912 was sent to us by S. M. Finegold, Veteran's Administration Center, Los Angeles, Calif.,...

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Objectives Human leukocyte antigen (HLA)‐B*5701 is strongly associated with developing a hypersensitivity reaction to abacavir (ABC) in White and Hispanic subjects. Across the UK, limited data exist on HLA‐B*5701 prevalence in HIV‐1‐infected subjects. We determined HLA‐B*5701 prevalence in the general HIV‐1‐infected population and in specific ethnic groups, particularly Black Africans who, in general, exhibit greater genetic diversity. We also compared HLA‐B*5701 results obtained from local laboratories with those from a central provider. Design and methods Multi‐centre, observational study. All HIV‐1‐infected adult individuals receiving care at participating centres were eligible, irrespective of treatment status or prior exposure to ABC. Subjects provided samples for HLA‐B*5701 assessment by both local (blood) and central laboratories (buccal swabs). HLA‐B*5701 prevalence was adjusted to represent the ethnic group composition of the general UK population, and by main ethnic group. Results From eight UK centres, 1494 subjects [618 (41%) White, 770 (52%) Black] were recruited. Eighty‐nine per cent of Black subjects reported an immediate country of origin in Africa. Overall adjusted HLA‐B*5701 prevalence was 4.55% [95% confidence interval (CI) 3.49% to 5.60%]. Among White subjects, prevalence was 7.93% (CI 5.80% to 10.06%). Among Black subjects, only two (both Ugandan) were HLA‐B*5701 positive giving a rate of 0.26% (CI 0.07% to 0.94%). Conclusions HLA‐B*5701 prevalence was similar to previously reported rates in White HIV‐infected subjects but considerably lower than that reported in Black HIV‐1‐infected subjects, as a result of the large proportion of Black African subjects.