Description of Leeds Acinetobacter Medium, a new selective and differential medium for isolation of clinically important Acinetobacter spp., and comparison with Herellea agar and Holton's agar

Abstract

Acinetobacter spp. are responsible for an increasing number of opportunistic, nosocomial infections. They have been isolated from diverse inanimate objects in the hospital environment and are resistant to most of the commonly used antibiotics. Existing media for the isolation of Acinetobacter spp. are either nonselective, allowing the growth of unwanted bacteria, or too inhibitory, inhibiting the growth of manyAcinetobacter strains. For the rapid isolation and effective control ofAcinetobacter infection, a new selective and differential medium, Leeds Acinetobacter Medium (LAM), has been developed to isolate Acinetobacter spp. from clinical and environmental sources. The concentration of antibiotics and other ingredients in this medium have been determined according to the results of MIC and viable counts performed for these ingredients. LAM was compared with other selective and differential media for the isolation ofAcinetobacter spp. from a local hospital environment and proved to be better in terms of recovery and selectivity.

Intestinal microflora of Estonian and Swedish infants

“…The bacteria were quantitated by serial dilutions on 10 different freshly prepared media, i.e. Fastidious Anaerobes Agar (FAA, LabM) for total anaerobes; Columbia CNA agar (BBL) for Gram-positive anaerobes; Schaedler agar (BBL) with vancomycin and nalidixic acid supplement (Oxoid) for Gram-negative anaerobes; Cefoxitin-Cycloserine-Fructose Agar (CCFA, Oxoid) supplemented with egg yolk and sodium taurocholate for Clostridium dificile; yeast-extract agar for total aerobes; yeast-extract agar with 6.5% of sodium chloride for staphylococci; Endo agar for coliforms; Leeds Acinetobacter Medium (LAM) with vancomycin at lOmg 1-', cefsulodin at 15 mg I-' and cephradine at 50 mg 1-' for acinetobacteria (19); MRS agar (Amersham) for microaerophiles such as lactobacilli and streptococci; and Sabouraud medium supplemented with penicillin (50 000 U I-') and streptomycin (40000U I-') for yeasts and fungi. The total counts of clostridia were estimated on FAA after ethanol treatment (20).…”

Acinetobacter , Chryseobacterium , Moraxella , and Other Nonfermentative Gram-Negative Rods

“…Selective media have been described for Acinetobacter spp. (8,113) and for Moraxella spp. (231), but their usefulness remains to be assessed.…”

Prevalence of Acinetobacter baumannii and other Acinetobacter spp. in faecal samples from non-hospitalised individuals

“…The samples were mixed to resuspend the faecal material, and then incubated with vigorous aeration for up to 48 h at 30°C to enrich for Acinetobacter spp. Following incubation, the cultures were streaked on to Leeds Acinetobacter Medium (LAM) [6] and blood agar. The plates were incubated aerobically at 30°C and examined after 24 h and 48 h for putative A. baumannii colonies (pink with mauve background on LAM [6]), or other colonies with a morphology on blood agar that was typical of Acinetobacter spp.…”

“…Following incubation, the cultures were streaked on to Leeds Acinetobacter Medium (LAM) [6] and blood agar. The plates were incubated aerobically at 30°C and examined after 24 h and 48 h for putative A. baumannii colonies (pink with mauve background on LAM [6]), or other colonies with a morphology on blood agar that was typical of Acinetobacter spp. (non-pigmented, white or cream-coloured, smooth to mucoid colonies, 1-2 mm in diameter [7]).…”

“…The simultaneous presence of mef(A) and erm(B) has been reported [4], while other reports have described mutations in regions V and II of the 23S rRNA gene, and also in genes encoding riboproteins L4 and L22. Resistance phenotypes correlating with these mutations may vary [5,6].…”