The Progressive Diagnostics Manufacturers epsilometer test (E test; AB Biodisk, Solna, Sweden), a quantitative variant of the disk diffusion technique, was evaluated comparatively to an agar dilution method for the antimicrobial susceptibility testing of Helicobacter pylori. A collection of 79 H. pylori clinical strains, including isolates with known resistance to various antimicrobial agents, was tested against 12 different antimicrobial agents. All strains were tested on Columbia agar supplemented with 10% horse blood. Plates were incubated at 37°C in microaerobic atmosphere (5% 02, 10% C02), and readings were done after 3 days of incubation. In general, E test MICs were easy to interpret and the correlation between MICs by the agar dilution method and the E test was good, with 86 and 99.5% of results being within, respectively, 1 and 2 log2 dilution steps in a total of 936 tests. All strains of H. pylori with documented resistance to the tested agents were detected by the E test. Thus, the E test appears to be an easy and reliable method for determination of MICs of antibiotics for H. pylori, and it may offer an interesting alternative to MIC determination by the agar dilution technique.

Four hundred strains of lactose-fermenting Enterobacteriaceae were tested for hydrolysis ofp-nitropheny1-j8-D-glucopyranosiduronic acid, the chromogenic enzyme substrate of I-glucuronidase. Escherichia coli was found to be homogeneous with respect to I-glucuronidase: more than 94% of the examined E. coli strains were positive, whereas none of the other lactose-fermenting strains possessed ,-glucuronidase activity. The qualitative 13-glucuronidase test, as rapid and simple as the o-nitropheny1- ,-D-galactopyranosidase test, proved to be of diagnostic value, especially in the identification of E. coli in primary urine cultures. No significant differences were observed in the results of experiments in which either substrate-impregnated disks prepared in the laboratory or commercially available tablets were used.

The in vitro susceptibilities of 37 clinical isolates of Alcaligenes denitrificans subsp. xylosoxidans to 24 antimicrobial agents were determined. Imipenem was the only drug with consistent activity (MIC for 90% of isolates, 2 micrograms/ml). Piperacillin, ticarcillin-clavulanic acid, ceftazidime, and co-trimoxazole were active against most strains. All the isolates were resistant to ampicillin, cefazolin, cefuroxime, cefamandole, cefotetan, ceftriaxone, cefotaxime, aztreonam, amdinocillin, and temocillin. Most isolates were resistant to the aminoglycosides tested, including amikacin. Lack of activity was also observed for all new 4-quinolone antimicrobial agents.

A modified decarboxylase assay medium (DCA medium) was used for studying the production of biogenic amines by Leuconostoc oenos DSM 20252 and two strains of Lactobacillus buchneri (Lb14 and St2A). The DCA medium contained histidine, lysine, ornithine and tyrosine as precursors of the respective biogenic amines. Under the experimental conditions both strains of Lact. buchneri produced > 90% of the maximum amount of histamine within 24 h. Only tyramine was produced by Leuc. oenos DSM 20252. accountine for 88% of the maximum theoretical amount within 24 h.

Pseudomonas paucimobilis has rarely been reported as an opportunistic human pathogen. We report the isolation of this organism in two patients who developed peritonitis during the course of intermittent or continuous ambulatory peritoneal dialysis. The origin of the infection was related to contamination of the dialysate in the first patient but could not be determined in the second case.