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At present, the rapid diagnosis of pulmonary tuberculosis rests with microscopy. However, this technique is insensitive and many cases of pulmonary tuberculosis cannot be initially confirmed. Nucleic acid amplification techniques are extremely sensitive, but when they are applied to tuberculosis diagnosis, they have given variable results. Investigators at six centers in Europe compared a standardized PCR system (Amplicor; Roche) against conventional culture methods. Defined clinical information was collected. Discrepant samples were retested, and inhibition assays and backup amplification with a separate primer pair were performed. Mycobacterium tuberculosis complex organisms were recovered from 654 (9.1%) of 7,194 samples and 293 (7.8%) of 3,738 patients. Four hundred fifty-two of the M. tuberculosis isolates from 204 patients were smear positive and culture positive. Among the culture-positive specimens, PCR had a sensitivity of 91.4% for smear-positive specimens and 60.9% for smear-negative specimens, with a specificity of 96.1%. Analysis of 254 PCR-positive, culture-negative specimens with discrepant results revealed that 130 were from patients with recently diagnosed tuberculosis and 94 represented a presumed laboratory error. Similar analysis of 118 PCR-negative, culture-positive specimens demonstrated that 27 discrepancies were due to presumed uneven aliquot distribution and 11 were due to presumed laboratory error; PCR inhibitors were detected in 8 specimens. Amplicor enables laboratories with little previous experience with nucleic acid amplification to perform PCR. Disease in more than 60% of the patients with tuberculosis with smear-negative, culture-positive specimens can be diagnosed at the time of admission, and potentially all patients with smear-positive specimens can immediately be confirmed as being infected with M. tuberculosis, leading to improved clinical management.

In the past 5 yr, an increased incidence of tuberculosis has been noted in the United States. Simultaneously, the population infected with human immunodeficiency virus-type I (HIV-I) and the number of cases of acquired immunodeficiency syndrome (AIDS) have increased. Selected areas of the United States have also reported increases in the frequency of drug-resistant isolates of Mycobacterium tuberculosis. Because our institution serves a population in which tuberculosis, AIDS, and drug resistant isolates of M. tuberculosis are frequently encountered, we sought to better define interrelationships among these factors by retrospectively reviewing the demographic, clinical, bacteriologic, and radiologic data for all adult patients in whom M. tuberculosis was isolated from a culture of respiratory-tract secretions during a 1-year period (June 1, 1988 to May 31, 1989). Two hundred forty-six patients were thus identified; 66.5% were U.S. born blacks, and 62.6% were 17 to 40 yr of age. Risk factors for HIV infection were present in 106 patients. The overall resistance rate (one or more drugs) = 30.9%, with primary resistance = 22.6% (35 of 155) and secondary resistance = 49.2% (29 of 59). In addition, 12 resistant isolates were found in 32 patients whose prior treatment status was indeterminate. Of the resistant isolates, 56.6% (43 of 76) were multiply resistant. Isoniazid resistance was noted in 90.7% (69 of 76) and rifampin resistance was noted in 50% (38 of 76) of the resistant isolates. No significant differences in the overall frequency of resistance were noted in patients at risk for HIV infection compared with those without these risks.(ABSTRACT TRUNCATED AT 250 WORDS)

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Empyema may rarely present as a delayed complication after laparoscopic cholecystectomy. Patients with this complication invariably have associated dropped gallstones in the peritoneal cavity. The gallstones may erode through the diaphragm or migrate through preexisting defects in the diaphragm. The latter are seen in over 50% of the elderly population and may predispose them to this rare complication.

The case history is presented of a 32 year old black man who developed haemoptysis leading to pulmonary haemorrhage and bilateral pulmonary infiltrates. He was found to have Kaposi's sarcoma ofthe lung with no evidence of skin or endobronchial lesions. (Thorax 1995;50:98- Laboratory data on admission were white blood cell count of 9000 with normal differential count, haemoglobin 13-2 g/l, platelet count 31 000/mm', prothrombin time 11 seconds (control 12 seconds), partial thromboplastin time 40 seconds (control 36 seconds), D-dimer >2, fibrinogen 4-8 g/l, electrolytes normal, blood urea nitrogen 22-84 mmol/l, creatinine 353-6 gimollI and glucose 6.6 mmol/l.Arterial blood tensions breathing 50% oxygen via a ventimask were pH 7 34, Pco2 3 19 kPa, Po2 11 30 kPa. The electrocardiogram showed left ventricular hypertrophy with non-specific ST segment depression in the anterolateral chest leads. Chest radiography showed extensive bilateral alveolar infiltrates on the left more than the right. He was given a rapid infusion of two litres of saline and his blood pressure improved to 100/60. Broad spectrum antibiotics (vancomycin, erythromycin, and ticarcillin) were started. Over the next few days his clinical state, platelet count, and renal function improved, but he continued to have episodes of haemoptysis and worsening hypoxaemia. Other investigations including sputum culture, blood culture, and sputum Legionella direct fluorescent antibody (DFA) were all negative. In view of his fluctuating pulmonary infiltrates bronchoscopy was performed and revealed normal vocal cords, trachea, carina, and bronchi. There was haemorrhagic fluid in several airways which was easily aspirated and no endobronchial lesions were noted. A transbronchial biopsy sample and bronchoalveolar lavage (BAL) fluid from the left lower lobe revealed negative DFA for Legionella, smears for acid fast bacilli, and fungi.The BAL fluid tested positive for cytomegalovirus by monoclonal antibody studies, but no viral inclusions were noted. Gancyclovir nevertheless was added to the treatment. Histological examination of the transbronchial biopsy specimen revealed an exuberant collection of spindle-shaped cells which were probably of endothelial origin and were von Willebrand antigen positive, compatible with Kaposi's sarcoma. Stains for cytokeratin and muscle specific antigen were negative in these tumour cells. Gallium scanning did not reveal any ab-