Interspecies Transformation of Acinetobacter : Genetic Evidence for a Ubiquitous Genus

Abstract

The availability of a strain of Acinetobacter competent for transformation has made it possible to demonstrate the genetic relatedness of a large variety of gram-negative, oxidase-negative, nonmotile, and aerobic coccobacilli originally classified into eleven different genera. Deoxyribonucleic acid (DNA) species from 265 such strains are capable of transforming stable auxotrophs of the competent Acinetobacter to prototrophy. The compositions of these DNA species vary from 40 to 46.8% guanine plus cytosine. Strains with widely differing phenotypic properties are also included in this collection of acinetobacters. DNA species from all oxidase-positive strains of Moraxella and from a variety of common bacteria are unable fo transform the competent Acinetobacter. Although acinetobacters are usually considered to be unable to reduce nitrate to nitrite, six strains known to carry out this reduction have been shown to be authentic acinetobacters since their DNA species readily transform the competent Acinetobacter auxotrophs to prototrophy. In contrast to previous findings that acinetobacters rarely grow with glucose as a sole carbon source, the results of the present study show that 17 of the 265 strains grow readily in a glucosemineral medium, and 48 other strains can mutate spontaneously to grow in such a medium. A second competent strain of Acinetobacter, originally unable to use glucose, D-xylose, or D-ribose as carbon sources, has been transformed for ability to dissimilate these compounds using DNA species from strains that normally grow on these sugars. Although most of the 265 Acinetobacter strains studied were originally grown on complex media when isolated from human sources, only nine of these strains require growth factors in order to grow in a mineral medium containing a single carbon and energy source. A simple transformation assay has been devised for rapid examination of large numbers of strains to determine whether or not they are acinetobacters. This assay, which is suitable for routine diagnostic work, includes a procedure for preparation of crude transforming DNA from a small quantity of bacterial paste. Samples of DNA prepared from Acinetobacter cultures that had died on slants and plates were still able to effect transformation of the competent auxotrophs to prototrophy.

Biofilm formation byAcinetobacter baumanniistrains isolated from urinary tract infection and urinary catheters

“…Urine samples and urinary catheters from patients with UTI were collected from two hospitals in Pune, India using standard procedures. The samples were collected aseptically and isolation was performed on selective Acinetobacter minimal medium (Juni, 1972), cystein lactose electrolyte deficient agar (HiMedia, Mumbai), Holton's medium (Holton, 1983) and violet red bile agar (HiMedia). UTI samples were suitably diluted and plated onto the selective agar media, while the urinary catheter surfaces were scraped aseptically and transferred to sterile medium.…”

Cloning and analysis of the polyhydroxyalkanoic acid synthase gene from an Acinetobacter sp.: Evidence that the gene is both plasmid and chromosomally located

“…The bacterial strains and plasmids used in this study are listed in Table 1. Acinetobacter strains were isolated from modified activated sludge treatment plants and identified by a transformation test [14]. Acinetobacter strains were grown at 30°C on a defined medium containing acetate as the sole source of carbon and energy (referred to as ADM) [15].…”

Plasmid transfer to indigenous marine bacterial populations by natural transformation

“…Transformation experiments were performed by mixing fresh cultures of the isolates with cell lysates from rifampin-resistant derivative strains on the surface of an ASWJP + PY plate and incubating overnight at 28°C. Spontaneous rifampin resistant mutants were obtained by plating on selective media and crude cell lysates of these rifampin resistant mutants were prepared by the method of Juni [28]. Controls lacking recipient cells or lacking cell lysates from rifampinresistant strains were performed.…”