Comparison of the amplified Mycobacterium tuberculosis (MTB) direct test, Amplicor MTB PCR, and IS6110-PCR for detection of MTB in respiratory specimens.

Several nucleic acid amplification techniques (NAAT) have been developed for rapid and direct detection of Mycobacterium tuberculosis (MTB) from clinical specimens. This study compared the performances of the Gen-Probe Amplified MTB Direct Test (AMDT), Roche Amplicor MTB PCR test, and an IS6110-PCR assay with acid-fast smear and culture in the detection of MTB from 428 respiratory specimens from 259 patients. Patients' charts were reviewed for clinical correlation. Of 98 specimens that were clinically positive for MTB, acid-fast smear was positive in 50% of cases, culture in 93%, IS6110-PCR in 83%, AMDT in 84%, and Amplicor MTB PCR in 80%. Of 337 specimens that were negative for MTB, 117 (35%) were positive for nontuberculous mycobacteria. Specificities were as follows: smear, 89%; culture, 100%; IS6110-PCR, 99%; AMDT, 98%; and Amplicor MTB PCR, 96%. The accuracies of the tests were 80%, 98%, 96%, and 92%, respectively. MTB culture-positive specimens that were smear-negative were detected by AMDT and IS6110-PCR in 77% of cases and by Amplicor MTB PCR in 70%. NAAT was less sensitive than was culture for detection of MTB, but all these techniques had acceptable accuracy and were completed within hours. NAAT may be useful for rapid screening of respiratory specimens to distinguish MTB from nontuberculous mycobacteria infection in order to isolate patients.

Corneal ulcer due to Exserohilum longirostratum.

A 47-year-old man sustained a traumatic injury to the left eye, and a corneal ulcer subsequently developed. Histologic examination of the corneal tissue revealed septate hyphae with acute angle branching. The mycologic and bacterial cultures yielded a dematiaceous fungus with ellipsoidal pigmented macroconidia borne sympodially on geniculate conidiophores. The multicellular macroconidia had prominent, protruding, truncated hila. The shorter macroconidia averaged 5-7 septa, and the longer conidia 13-21 septa. Growth on V-8 agar, alternating between fluorescent light and the dark, produced macroconidia more than 200 microns in length. The isolate was identified as Exserohilum longirostratum. This is believed to be the first documented case of mycotic keratitis caused by the phaeohyphomycete E longirostratum.

Creatine kinase B subunit as measured with a radioimmunoassay kit in detection of acute myocardial infarction.

Results with a commercial radioimmunoassay (RIA) reagent kit for quantification of the creatine kinase B subunit (CK-B) (Nuclear-Medical Laboratories, Irving, TX 75061) were compared with results obtained by electrophoresis for patients consecutively admitted to our coronary care unit for suspected acute myocardial infarction. Analytical sensitivity, precision, and specificity of the RIA were satisfactory. Its clinical efficacy was assessed in 97 patients suspected of having had an acute myocardial infarction. Of 30 patients who had had an acute myocardial infarction, increased CK-B was detected by RIA in 30 and by electrophoresis in 27. The temporal relationship between CK-B by RIA and CK-MB by electrophoresis was similar. Of 66 admissions where infarction was not established, CK-B was negligibly increased in samples from four patients by RIA, and from one by electrophoresis. Although not abnormally increased (greater than 5 U/L), CK-MB was detected by electrophoresis in samples from another five of these 66 patients. We conclude that estimation of CK-B by this RIA is an excellent alternative to estimation of CK-MB by electrophoresis in patients suspected of having had an acute myocardial infarction.

Two radioimmunoassays compared with isoenzyme electrophoresis for the detection of serum creatine kinase-MB in acute myocardial infarction.

We have evaluated two commercial radioimmunoassay (RIA) reagent kits for the estimation of the MB isoenzyme of creating kinase (CK). Although both methods use CK-B antisera and radioiodinated CK-B, one ("M" for Mallinckrodt) uses hybridized CK-MB for calibration, while the other ("NMS" for Nuclear Medical Systems) uses CK-B. Both assays provide adequate sensitivity, precision, and specificity for the estimation of serum CK-MB. Ninety-nine patients admitted consecutively to our coronary care unit were studied. Apparent CK-MB was measured by both RIAs and results compared with CK-MB enzymatic activity after electrophoresis (E). CK-MB was elevated, as judged by E and by M, in all of 42 patients with acute myocardial infarction (AMI), and in 40 of the 42 by NMS. Of the 57 patients who did not have an AMI, eight had elevated CK-MB by E, 16 by M, and 25 by NMS. Patients with persistently elevated apparent CK-MB concentrations not associated with AMI were identified by M and by NMS, but not by E. The ability to differentiate AMI from no infarction in patients was best with E, and was not satisfactory by NMS. Although the detection of AMI by M equaled that by E, the large number of apparent false-positive results hindered the clinical application of RIA CK-MB measurements.

Histopathology of marine vibrio wound infections.

Although marine vibrio wound infections and septicemia are being reported with increasing frequency, description of the histopathologic changes has been scanty. The histologic alterations in three patients with primary marine vibrio wound infections are presented. The lesions are characterized by intense acute cellulitis of the subcutis with much tissue destruction and extension into the adjacent dermis. The superficial dermis is devitalized and lacks an inflammatory cellular infiltrate. Subepidermal noninflammatory bullae are formed. Many organisms are seen both within the areas of intense acute inflammation and in devitalized areas. Organisms and inflammation are especially oriented around vessels, with associated acute vasculitis. It is concluded that the morphologic picture in marine vibrio wound infections is nonspecific yet characteristic.