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Some chronic middle ear infections may contain viable bacteria not detectable by bacterial cultures. Otitis media with effusion is a middle ear infection with fluid collection that brings many children to the doctor and can cause hearing and speech disorders. Researchers used genetic amplification to look for evidence of bacterial metabolic activity in 93 effusions collected during middle ear surgery in children. Bacterial RNA was detected, but cultures were negative, in 31.2% of effusions. Most effusions are sterile, but bacterial cultures may miss live organisms in some cases., Context.--Otitis media with effusion (OME) can lead to significant hearing loss in children. Although previous studies have shown that bacterial DNA is present in a significant percentage of effusions sterile by culture, whether the DNA represents viable organisms or "fossilized remains" is unknown. Objective.--To determine if bacterial messenger RNA (mRNA), as detected by a reverse transcriptase-polym erase chain reaction (RT-PCR)-based assay, is present in chronic pediatric middle ear effusions that contain bacterial DNA but are sterile by standard cultural methods. Bacterial mRNAs have a half-life measured in seconds to minutes; therefore, detection of bacteria-specific mRNAs would be evidence that metabolically active organisms are present. Design.--Blinded comparative study. Patients.--A total of 93 effusions from pediatric outpatients seen for myringotomy and tube placement for chronic (>3 months) OME (median age of children, 17 months). Setting.--Tertiary care pediatric hospital. Main Outcome Measures.--Percentage of positive test results for RT-PCR-based assays compared with culture for Haemophilus influenzae and concordance between RT-PCR and PCR-based findings for bacterial nucleic acids. Results.--Eleven (11.8%) of the 93 specimens tested positive by culture, PCR, and RT-PCR for H influenzae. A total of 29 specimens (31.2%) were positive by PCR but negative by culture for H influenzae. All 29 specimens were positive by RT-PCR for H influenzae-specific mRNA. Conclusions.--The RT-PCR-based assay system can detect the presence of bacterial mRNA in a significant percentage of culturally sterile middle ear effusions, establishing the presence of viable, metabolically active, intact organisms in some culture-negative OME. JAMA. 1998;279:296-299

Objectives: Because there are no markers for hereditary pancreatitis (HP), diagnosis has relied on clinical features and inferences. Identification of the HP disease gene locus on chromosome 7q35 provides the first genetic marker for HP, allowing an accurate comparison of the clinical diagnosis of HP with the presence of a high-risk HP haplotype. Our objectives were to compare the clinical diagnosis of HP with inheritance of the HP gene and to characterize the common clinical features. Methods: A detailed questionnaire was administered to 102 study participants of a large HP kindred. Blood samples were taken for DNA extraction and high-risk haplotype determination. Clinical findings were compared with the presence of a high-risk haplotype. Results: A family tree of more than 500 members and eight generations was constructed, and clinical features of the 102 participants were determined. HP occurred before the age of 5 yr in 58% of subjects, who presented with common symptoms of abdominal pain, nausea/vomiting, and frequent attacks. Thirty-five probands, of whom 80% had clinical symptoms, carried the high-risk haplotype, confirming previous estimates of 80% penetrance. Thirty-two of the study participants had been clinically diagnosed with HP. whereas 70 were clinically unaffected. With regard to the presence of the high-risk haplotype, 87.5% of the clinically diagnosed patients were affected by HP (true positive), whereas 12.5% did not carry the high-risk haplotype (false positive). Seven obligate carriers were identified through DNA analysis; three had previously been unrecognized because of lack of affected offspring. Conclusions: The diagnosis of hereditary pancreatitis on clinical grounds alone may be inaccurate in less severe cases, as is the exclusion of carrier status through family tree analysis. Therefore, a definitive diagnosis of hereditary pancreatitis in equivocal cases or exclusion of a carrier state should include analysis of genetic markers. [ABSTRACT FROM AUTHOR]