Molecular detection of Mycoplasma pneumoniae in adults with community-acquired pneumonia requiring hospitalization.

Mycoplasma pneumoniae infection was diagnosed in 18 (12.5%) of 144 adults hospitalized with community-acquired pneumonia. The infection was demonstrated by PCR in 15 patients and by serology, using two methods, in 10 patients. The mean age of the 8 patients with positive M. pneumoniae PCR and negative serology was significantly higher than that of the 10 patients with positive serology.

Results of molecular detection of Mycoplasma pneumoniae among patients with acute respiratory infection and in their household contacts reveals children as human reservoirs.

During a 30-month prospective study in The Netherlands, the distribution of Mycoplasma pneumoniae and respiratory viruses among 1172 patients with acute respiratory infection (ARI) who were treated in the outpatient general practitioner setting was studied. M. pneumoniae, as detected by polymerase chain reaction analysis, was present in 39 (3.3%) patients. The infection rate was similar in all age groups. Nose and throat samples collected from 79 household contacts of M. pneumoniae-positive index patients revealed M. pneumoniae in 12 (15%) cases. The frequency of M. pneumoniae among household contacts of index patients treated with appropriate antibiotics and untreated index patients was similar. Nine of the 12 M. pneumoniae-positive household contacts were <16 years old (P=.02), and 4 (44%) of them did not develop ARI. Apparently, children are a relevant reservoir for M. pneumoniae.

Diagnosis of hepatitis C virus infection using two second-generation enzyme immunoassays with a recombinant immunoblot assay for confirmation.

A total of 1,016 serum samples from patients with either non-A, non-B hepatitis or risk factors for hepatitis C virus (HCV) infection were examined in two second-generation enzyme immunoassays (EIAs), the UBI HCV EIA (Organon Teknika, The Netherlands) and the Wellcozyme anti-HCV (Murex Diagnostics, UK), for detection of antibodies to HCV. An immunoblot assay that uses four recombinant antigens, the 4-RIBA (Chiron, USA), was used as a confirmatory assay. Of the 1,016 samples, 195 (19.2%) were reactive in both EIAs, while ten yielded discrepant results. One hundred eighty of the 195 (92%) positive reactions were confirmed in the 4-RIBA; 13 sera yielded an indeterminate result and two were negative. None of the sera with discrepant results reacted positively in the confirmatory test, while two sera showed an indeterminate pattern. In contrast to the screening of antibodies to HCV among blood donors, confirmatory testing of antibodies to HCV with the 4-RIBA seems to have limited added value in the diagnostic examination of clinical samples from patients with suspected HCV infection.

Mutation of the POU-specific domain of Pit-1 and hypopituitarism without pituitary hypoplasia.

A point mutation in the POU-specific portion of the human gene that encodes the tissue-specific POU-domain transcription factor, Pit-1, results in hypopituitarism, with deficiencies of growth hormone, prolactin, and thyroid-stimulating hormone. In two unrelated Dutch families, a mutation in Pit-1 that altered an alanine in the first putative alpha helix of the POU-specific domain to proline was observed. This mutation generated a protein capable of binding to DNA response elements but unable to effectively activate its known target genes, growth hormone and prolactin. The phenotype of the affected individuals suggests that the mutant Pit-1 protein is competent to initiate other programs of gene activation required for normal proliferation of somatotrope, lactotrope, and thyrotrope cell types. Thus, a mutation in the POU-specific domain of Pit-1 has a selective effect on a subset of Pit-1 target genes.