Evaluation of a rapid latex slide agglutination test for herpes simplex virus as a specimen screen and culture identification method.

A total of 449 clinical specimens and 199 culture fluids were tested using the Virogen Herpes Slide Test (Wampole Laboratories, Div. Carter-Wallace, Inc., Cranbury, N.J.), a rapid latex agglutination procedure. The results were compared with those obtained with isolation of herpes simplex virus in cell culture followed by identification using immunoperoxidase or fluorescent reagents. The sensitivity, specificity, and positive and negative predictive values of the direct test were 49.7, 93.4, 96.0, and 37.1%, respectively. The sensitivity and specificity of the latex agglutination test for culture confirmation were 75.9 and 100%, respectively.

Comparison of the Ortho Cultureset (Vero cells) and Difco Cellmatics system (mink lung and primary rabbit kidney cells) for the detection of herpes simplex virus from clinical specimens.

Two Cellmatics (Difco) Herpes simplex virus (HSV) detection systems, one with mink lung cells (ML) and the other with primary rabbit kidney cells (PRK) and the Cultureset (Ortho) system with Vero cells were compared for their ability to detect previously positive specimens. One hundred fifty patients specimens positive for HSV in either Vero or PRK cells prior to freezing at -70 degrees C were thawed once, diluted to 1:8, and inoculated in duplicate into each cell system. Positive cultures were detected using each kit's immunoperoxidase method. All three cell lines were stained at 24 hr followed by a final staining of negative cultures at 48 hr for Cultureset and at 72 hr for Cellmatics as per kit instructions. At 24 hr percent detection was: Cellmatics (ML) = 85%, Cellmatics (PRK) = 81%, Cultureset (Vero) = 74%. At final staining percent detection was 94%, 92%, and 84%, respectively. The Cellmatics system has the advantage of fewer steps in the staining procedure and no manipulation of coverslips because staining is performed in the tubes. As employed in these commercial systems, the Cellmatics system with ML cells is more sensitive than the Cultureset with Vero cells (p less than 0.001) and comparable to the Cellmatics system with PRK.

Isolation of Corynebacterium aquaticum from spinal fluid of an infant with meningitis.

A 4-week-old female was hospitalized because of vomiting, irritability, and nuchal rigidity. A spinal fluid culture yielded Corynebacterium aquaticum. The diagnosis of C. aquaticum meningitis in this infant was supported by the following cerebrospinal fluid findings: Gram stain, elevated protein, hypoglycorrhachia, positive C-reactive protein, and polymorphonuclear leukocytosis. Antigen studies for common bacterial causes of meningitis were negative. C. aquaticum is a rare cause of human disease and may be initially confused with Listeria monocytogenes, which is a more common gram-positive, motile rod associated with meningitis in infants.

Comparison of a latex agglutination test with five other methods for determining the presence of antibody against cytomegalovirus.

A latex agglutination test for determination of antibody against cytomegalovirus was compared with five other methods: a solid-phase fluorescent immunoassay, an indirect hemagglutination test, two solid-phase enzyme immunoassays, and an indirect fluorescent-antibody method, with sera collected from 210 random blood donors. Of the sera tested, 28% were positive for anti-cytomegalovirus by concordance of four or more methods. The latex agglutination test performed well, with a sensitivity of 100%, a specificity of 99%, and positive and negative predictive values of 97 and 100%, respectively. The methods were also evaluated for the number of sera requiring repeat testing, equivocal results after retesting, ease of performance, turnaround time, and technical demands. The tests which best met the requirements for a screening test were the solid-phase fluorescent immunoassay, the indirect hemagglutination test, and the latex agglutination test. The latex agglutination test is a valuable screening tool for detecting total anti-cytomegalovirus which has high sensitivity, high negative predictive value, and rare equivocal results and also has the added advantages of ease of performance and rapid turnaround time.

Enhanced detection of bacteremia with a new BACTEC resin blood culture medium.

In this multicenter study, 621 sets of blood culture specimens were drawn from 280 patients who were suspected of being septic and who were receiving antimicrobial therapy. Equal volumes of each specimen were inoculated into BACTEC 6B and 16B media. The 16B medium contained adsorbent and cationic resins for neutralizing the effects of the drugs. Of the 621 sets drawn, there were 72 positive cultures in 16B and 52 positive cultures in 6B. In 23 cases the organism was detected only in the 16B medium, and in 3 cases the organism was detected in 6B only. The remaining 49 positives were detected in both culture bottles. In 13 of these 49 cultures, detection in 16B was made between 1 and 5 days earlier than in 6B, whereas 3 of 49 specimens were detected 1 day earlier in 6B; the remaining 33 cultures became positive at approximately the same time in both media. There were a total of 43 patients with positive cultures in this study. Of these patients, 28 had sepsis detected in both the 16B and 6B media. The 6B medium alone detected an additional three cases of sepsis, and the 16B resin medium alone identified 12 additional cases. Supplementary culturing of samples from patients receiving antimicrobial therapy significantly increased the number of positive cultures and positive patients, as well as significantly shortening the time to positivity in these cultures.

Anaerobic radiometric detection of facultative Gram-positive cocci in blood.

Radiometric detection of facultative gram-positive cocci, particularly streptococci, has been reported to be suboptimal. A recently marketed anaerobic Bactec bottle (7C) with purportedly improved capability to detect facultative gram-positive cocci in blood was compared with the previously available bottle in a study of simulated bacteremia. The Bactec system detected all beta-hemolytic streptococci and enterococci tested. Detection of alpha-hemolytic streptococci was improved in general. However, detection of Streptococcus mutans, Streptococcus bovis and Streptococcus pneumoniae remained suboptimal under anaerobic conditions. A metabolic index unit threshold for positivity of 15 is recommended when employing the anaerobic Bactec bottle.

Evaluation of the necessity for routine terminal subculturing of blood cultures negative by radiometric methods.

A retrospective review of 18,130 blood cultures performed with a BACTEC 225 indicated that terminal subculturing of bottles negative after 7 days of testing did not recover organisms which affected patient care or the length of patient hospitalization.

Performance of a commercial microdilution minimal inhibitory concentration procedure for aminoglycoside susceptibility testing of Pseudomonas aeruginosa.

The accuracy of quantitative aminoglycoside minimal inhibitory concentration (MIC) determinations was evaluated with the Micro-Media Systems microdilution MIC panel and Pseudomonas aeruginosa. Without Mg++ and Ca++ supplementation, very major interpretive discrepancies occurred. A simple, in-expensive cation supplementation procedure was evaluated to correct the discrepancies. The necessity of cation supplementation for susceptibility testing of P. aeruginosa when employing MIC procedures is stressed.

Development of five-hour radiometric serum antibacterial assay for gram-positive cocci.

A preliminary report on a 5-hr radiometric serum antibacterial assay (ABA) for Gram-positive cocci is presented. The method agreed within +/- one twofold dilution with static ABA endpoints in 24/26 (92%) of the assays and with cidal ABA endpoints in 23/26 (88%) of the assays performed.

Role of a cefoxitin-inducible beta-lactamase in a case of breakthrough bacteremia.

Development of resistance during therapy with cefamandole contributes to treatment failure. A simple cefoxitin disk test was recently described which detects a cefamandole-active inducible beta-lactamase not otherwise detectable with cefamandole as the inducer. A case of breakthrough Enterobacter bacteremia due to selection of a resistant subpopulation is reported in an immunocompromised patient. The use of this simple disk test in selected clinical cases is advocated.

Detection of group D and viridans streptococci in blood by radiometric methods.

A prospective study was conducted to evaluate the radiometric detection of group D and viridans streptococci in blood, using three media preparations, Bactec 6A and 6B isotonic media and 8B hypertonic medium. All enterococci tested were detected by the 6A and 6B media. However, the 6A medium failed to detect 76% of the Streptococcus bovis isolates and 57% of the viridans streptococci, whereas all S. bovis isolates and 95% of the viridans streptococci were detected with the 6B formulation. No improvement in detection was noted in comparing the 6B and the 8B hypertonic media. The importance of adequate detection of this group of organisms, especially in patients with endocarditis, is discussed.

Torulopsis glabrata fungemia secondary to stone colonization.

A case of Torulopsis glabrata fungemia with persistent funguria and pyelonephritis secondary to colonization of renal calculus is presented. The importance of secondary colonization of renal calculi in persistent infection and septicemia is discussed.