European Journal of Clinical Microbiology最新文献

Two cases of bacteremic infection due to aerococci in granulocytopenic patients with acute leukemia and oral mucositis are described. Strains isolated from blood cultures of both patients were resistant to the antibiotics given orally for prophylaxis. One patient died in septic shock; surveillance cultures from oral washings in the other repeatedly showed high concentrations of aerococci. Aerococci were also isolated from surveillance cultures taken from 5 of 17 other patients with acute leukemia; however, their viable counts were lower than in the surviving patient.

A four-month pilot study involving 100 volunteers, 100 hospitalised patients not on antibiotics and 100 patients on antibiotics was performed using a non labor-intensive system involving inoculator, laser colony counter and 14-cm petri dishes containing MacConkey medium to determine the number of aerobic gram-negative bacilli present in saliva. All colonies greater than or equal to 0.75 mm in diameter were found to be aerobic gram-negative bacteria. This was also valid for Pseudomonas aeruginosa, but only after incubation for 48 h. This study showed that the novel and practical technique used can be applied to a large number of saliva specimens, and antibiotics have limited impact on the buccal microflora (intensive care unit excluded).

A miniaturized 2-h system for detection of lactose-negative potentially enteropathogenic bacteria on the basis of nine enzymatic tests was evaluated. The system was challenged with 210 strains of lactose-negative and lactose-positive species grown on MacConkey agar. Specific and constant patterns were found for Salmonella, Shigella A-C, Yersinia enterocolitica, Aeromonas spp. and Vibrio cholerae. Shigella sonnei and Hafnia alvei had an identical pattern, likewise Plesiomonas shigelloides, halophilic vibrios and Pseudomonas aeruginosa.

The growth media peptone yeast extract glucose broth and gas liquid chromatography broth were compared with respect to their suitability for anaerobic bacteria, using 63 strains belonging to 12 species. After incubation for 24 and 48 h the broth cultures were subjected to viable counts and gas chromatographic analysis of short-chain alcohols and fatty acids in head-space vapours and ether extracts. Head-space analysis was superior to the ether extraction method for detecting the rapidly eluting short-chain alcohols. The gas liquid chromatography medium provided superior growth and contained fewer compounds that interfered with the chromatographic analyses. Whereas incubation in gas liquid chromatography medium for 24 h gave characteristic chromatograms for all but one of the studied species, most species required 48 h of incubation in peptone yeast extract glucose medium. Gas liquid chromatography broth is the preferred substrate for use in gas chromatographic identification of anaerobic bacteria.

A 29-month prospective study was carried out in a leukemia unit with the aim of investigating the epidemiology of Clostridium difficile infections and limiting their spread. Systematic cultures of stools and assays for cytotoxin were performed on patient admission and at weekly intervals, yielding 1,355 cultures and assays. The study period was divided in period A, before total unit renovation, and period B, afterwards. During period B all patient carriers of Clostridium difficile received vancomycin. A comparison of the two periods showed that the percentage of positive cultures fell from 16.6% to 3.6% and the positive toxin assays from 9.9% to 1.2%. It was concluded that colonization by Clostridium difficile can be prevented in hospital wards with generally high rates of infection by a combination of decontamination of the environment, introduction of preventive measures and treatment of Clostridium difficile carriage with vancomycin.

An enzyme immunoassay (EIA) and an enzyme-linked fluoroimmunoassay (ELFIA) utilizing monoclonal antibody to major outer membrane protein of Chlamydia trachomatis L2 were developed for rapid detection of chlamydial antigen in clinical samples. The EIA and ELFIA could detect levels of purified chlamydial outer membrane protein as low as 1.0 and 0.2 ng/ml respectively. However, when EIA and ELFIA were compared to chlamydial isolation using 160 patient samples, the sensitivity rate was 68% and 85% respectively. The sensitivity of the antigen detection method might be increased by simply using less diluted samples than in the present study. Chlamydial antigen was also demonstrated by EIA and ELFIA in 15% and 23% of culture-negative samples. The reason for these false-positive findings remains undetermined.

Extracts of representative mycobacteria were examined by thin-layer chromatography for glycosylphenolphthiocerol dimycocerosates. The glycolipid typical of Mycobacterium bovis was also found in Mycobacterium africanum and Mycobacterium microti, but it was absent in Mycobacterium bovis AN 5. Mycobacterium gastri strains contained a glycolipid which was chromatographically similar to that in Mycobacterium kansasii. Representatives of Mycobacterium marinum produced a distinct glycolipid type, and one strain had major amounts of a more polar variant. The sugar moieties of purified lipids, including that from Mycobacterium leprae, were identified by thin-layer chromatography of methyl glycosides in acid methanolysates.