Inflammatory and cardiac biomarkers are differentially expressed in clinical stages of Chagas disease.

BACKGROUND: Chagas disease has a long clinically silent period following Trypanosoma cruzi infection and before development of overt clinical pathology; detectable biomarkers of infection and pathogenesis are urgently needed. We tested 22 biomarkers known to be associated with cardiomyopathy to evaluate if a biomarker signature could successfully classify T. cruzi seropositive subjects into clinical Chagas disease stage groups. METHODS: This cross-sectional retrospective case-control study enrolled T. cruzi seropositive blood donors (BD) who were further characterized as having chronic Chagas cardiomyopathy (CC-BD) or not (nonCC-BD) and seronegative (SN) control donors; we also included clinically diagnosed Chagas cardiomyopathy patients (CC-P). All subjects underwent a health history questionnaire, medical examination, electro- and echocardiograms (ECG and Echo) and phlebotomy. Biomarkers were measured on blinded samples by luminex bead array and Ortho VITROS. RESULTS: A clear biomarker pattern was observed only in more severe cardiac disease; this pattern included significantly elevated levels of inflammatory cytokines IFN-γ, IL-6, IL-10 and TNF-α and soluble cardiovascular disease biomarkers CK-MB, troponin, myoglobin, VCAM and NTproBNP while there were lower levels of MPO, PAI-1, and MCP-1. The markers determined to be the most predictive of disease by ROC curve analysis were NTproBNP and T. cruzi PCR status. CONCLUSIONS: Although many biomarkers demonstrated increased or decreased concentrations among the clinical forms of Chagas disease, NTproBNP and T. cruzi PCR were the only tests that would independently be of clinical value for disease staging, in concert with ECG, Echo and clinical assessments.

Analytical performance of an immunologic-based periodontal bacterial test for simultaneous detection and differentiation of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia.

The analytical performance of a membrane-based immunoassay for the simultaneous detection and differentiation of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, and Prevotella intermedia (including Prevotella nigrescens) was investigated. Positive reactions were observed for 71 of 71 reference strains and recent oral isolates of A. actinomycetemcomitans, P. gingivalis, and P. intermedia. No cross-reactivity was observed with 39 other common oral and environmental species. The specificity of the test was unaffected by the presence of potential oral interferents including whole blood, white blood cells, mucin, saliva, toothpastes, and oral rinses. A proficiency test by dental professionals using a standardized set of unknown simulated samples yielded a sensitivity of 97% (116/120) and a 100% specificity (240/ 240). An additional group including dental professionals and high school students was shown to be 99% proficient (1385/1397) in distinguishing proper from improper test function when processing control samples with normal test devices and devices with simulated error conditions. Comparisons to a culture standard for 104 subgingival plaque samples collected from 26 adult periodontitis patients yielded > 98% specificity for each of the test bacteria. In addition, the detection threshold for the test was determined to be equivalent to 10(4) cultivable test bacteria when compared to the culture standard. The data indicate that this membrane immunoassay is a valid and easy-to-use method for the detection of A. actinomycetemcomitans, P. gingivalis, and P. intermedia in subgingival plaque, at levels above the detection threshold of the test.

Rapid, direct antibiotic susceptibility testing of blood culture isolates using the Abbott Avantage system.

The Abbott Avantage (AV) is an updated version of the MS-2 system that provides antibiotic-susceptibility results in four to six hours. Although the system compared favorably with reference methods in several laboratory evaluations, little information exists regarding its performance with inocula obtained directly from blood cultures. The authors compared AV and a modified disk-diffusion test using standardized inocula obtained directly from the blood culture bottles for 58 isolates (46 patients). All isolates were also tested by the National Committee for Clinical Laboratory Standards standard disk-diffusion method, using inocula obtained from subcultures of the positive bottles. AV results for 553 antibiotic tests agreed with the direct disk results in 92.6% of the tests, and the agreement with the standard disk results was 88.2%. The concordance between direct and standard disk results was 93.5%. There were 2.2% very major, 1.8% major, and 7.8% minor discrepancies between results obtained with direct AV and standard disk methods. False sensitivity of Klebsiella pneumoniae to ampicillin and carbenicillin and induced clindamycin resistance in staphylococci were noted with AV. When one considers only the clinically meaningful antibiotic-organism combinations, direct AV is an acceptable, rapid alternative to direct disk susceptibility testing.