The reported rate of detection of Chlamydia pneumoniae DNA within atherosclerotic lesions by PCR varies between 0 and 100%. In this study, identical sets of coded experimental atheroma samples (n ‫؍‬ 15) and spiked controls (n ‫؍‬ 5) were analyzed by 16 test methods in nine centers by means of PCR. The positive controls were correctly identified to levels of 1, 0.1, and 0.01 inclusion bodies of C. pneumoniae/ml of tissue homogenate by 16 (100%), 11 (69%), and 3 (19%) of the test methods, respectively. Three out of 16 negative controls (19%) were rated positive. Positivity rates for atheroma samples varied between 0 and 60% for the different test methods, with the maximum concordant result for positivity being only 25% for one carotid artery sample. There was no consistent pattern of positive results among the various laboratories, and there was no correlation between the detection rates and the sensitivity of the assay used.

For the purpose of collecting Chlamydia pneumoniae strains of vascular origin that could be grown continuously in vitro, a cell culture system has been established. Using different types of vascular specimens obtained from 38 patients, Chlamydia pneumoniae could be isolated in three (7.9%) cases. The strains were obtained from specimens of the carotid artery, the femoral artery and an infrarenal aneurysm of the abdominal aorta of three male atherosclerosis patients. Thus, viable Chlamydia pneumoniae strains are also present in vascular regions other than those hitherto described.

In a 3-month prospective study among 203 Austrian outpatients with diarrhea, the role of pathogenic Escherichia coli and the use of the polymerase chain reaction in screening Escherichia coli isolates from clinical stool specimens were evaluated. Enteroaggregative Escherichia coli and enterotoxigenic Escherichia coli combined were identified as the second most frequent cause of diarrhea. Of a total of 85 bacterial pathogens isolated from 80 patients, 15 were pathogenic Escherichia coli, 13 enteroaggregative Escherichia coli and two enterotoxigenic Escherichia coli. Enteropathogenic, enteroinvasive, and enterohemorrhagic Escherichia coli isolates were not detected.

Thirty-one isolates of Acinetobacter baumannii were collected from ten intensive care units of an Austrian university hospital. All isolates were typed by enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR). Two strains colonizing 13 infants in the neonatal intensive care unit were identified by ERIC-PCR. All other Acinetobacter baumannii isolates had highly divergent ERIC-PCR patterns, despite having the same antibiogram. Thus, a hospital-wide clonal distribution, as suggested by identical antibiogram patterns, was excluded by ERIC-PCR.