Clinical strains of Acinetobacter classified by DNA‐DNA hybridization

Abstract

Tjernberg, I. & Ursing. J. Clinical strains of ,lcinewhartrr classified by DNA-DNA hybridization. APMIS A collection of .-lcincrohn~tcr strains consisting of I68 consecutive clinical strains and 30 type and reference strains was studied by DNA-DNA hybridization and a few phenotypic tests. The field strains could be allotted to 13 DNA groups. By means of reference strains ten of these could be identified with groups described by Boiriw & Grirnonr (1986). while three groups were new: they were given the numbers 13-1 5. The type strain of .4. ruclior~~.~i.s,m.~recently described by Ni. rhimuru et al. ( 1988) was shown to be a member of DNA group 12. which comprised 3 1 clinical isolates. Of the 19 strains of A . ,jrinii. eight showed hemolytic activity on sheep and human blood agar and an additional four strains on human blood agar only.Strains of this species have previously been regarded as non-hemolytic. Reciprocal DNA pairing data for the reference strains of the DNA groups were treated by UPGMA clustering. The reference strains for .4. c~~~l~~o u r c~~i c~i r .~..4. haiiriiannii and for DNA groups 3 and 13 formed a cluster with about 70% relatedness within the cluster. Other DNA groups joined at levels below 6OYn.

Phylogenetic structures of the genus Acinetobacter based on gyrB sequences: comparison with the grouping by DNA-DNA hybridization

“…A phylogenetic tree constructed from these gyrB sequences by using the neighbour-joining method is shown in Fig, 1. The grouping of the strains examined in this tree was almost congruent with the genomic species determined by DNA-DNA hybridization studies (Bouvet & Jeanjean, 1989 ;Bouvet & Grimont, 1986;Tjernberg & Ursing, 1989). The genetic distances between the sequences within the same genomic species were mostly within 0.041 of the Kimura 2-parameter distances and within 0.183 of the synonymous distances (Jukes-Phylogeny of Acinetobacter species 0.05…”

“…Recent taxonomic studies have placed this genus within the y-subclass of the Proteobacteria (Rainey et al, 1994) and the genus has been resolved into seven valid species and at least 14 genomic species (DNA groups) by DNA-DNA hybridization studies (Bouvet & Jeanjean, 1989;Bouvet & Grimont, 1986;Gerner-Smidt & Tjernberg, 1993 ;Nishimura et al, 1988;Tjernberg & Ursing, 1989). Acinetobacter is a normal inhabitant of the skin in healthy people and is an opportunistic pathogen involved in outbreaks of hospital infections (Bifulco et al, 1989;Bouvet & Jeanjean, 1995;Seifert et al, 1997;Towner, 1997;Towner et al, 1991).…”

“…N, any base; R, A or G ; S, C or G ; Y, C or T; M, A or C. (1 997). The following 18 genomic species were examined in this study: 1-12 (Bouvet & Grimont, 1986;Nishimura et al, 1988;Tjernberg & Ursing, 1989); BJ13 (synonym of TU14)-BJ17 (Bouvet & Jeanjean, 1995); and TU13 (Tjernberg & Ursing, 1989).…”

“…Genomic species 8 and 9 are phenotypically indistinguishable, but have been proposed to be separated into two taxa by DNA-DNA hybridization (4). However, the ATm values for genomic species 8 and 9 were in the range 4 -5 4 "C and the unification of genomic species 8 and 9 has been proposed by several investigators (Janssen et al, 1997 ;Tjernberg & Ursing, 1989). If the two genomic species are identical, it is not surprising that the gyrB analysis failed to differentiate them.…”

Diverse responses to UV light exposure in Acinetobacter include the capacity for DNA damage-induced mutagenesis in the opportunistic pathogens Acinetobacter baumannii and Acinetobacter ursingii

“…Given the tremendous range of variation across the genus, this suggests that while UV survival mechanisms are highly variable between species, they may be consistent within each species. However, as hypothesized, there was no association between the type of umuDC locus and strain survival, although two of the top five survivors lacked any of the type A-D umuD alleles.Survival after UV exposure was, however, associated with belonging to either the Acb group or a haemolytic species [A. gyllenbergii and genomic groups 6, 13, 14 and 16 (Tjernberg & Ursing, 1989)]. Each of these groups had a statistically lower survivorship than non-Acb or nonhaemolytic species (each group tested independently with P,0.05 in a Mann-Whitney U test).…”