Procalcitonin levels in patients with positive blood culture, positive body fluid culture, sepsis, and severe sepsis: a cross-sectional study.

BACKGROUND: Numerous investigations on procalcitonin (PCT) have been carried out, although few with large sample size. To deal with the complexity of sepsis, an understanding of PCT in heterogeneous clinical conditions is required. METHODS: Hospitalized patients aged 10-79 years were included in this retrospective and cross-sectional study. PCT tests were assayed within 2 days of blood culture. RESULTS: A total of 2952 cases (from 2538 patients) were enrolled in this study, including 440 cases in the 'positive BC' group, 123 cases in the 'positive body fluid culture' group, and 2389 cases in the 'negative all culture' group. Median PCT values were 4.53 ng/ml, 2.95 ng/ml, and 0.49 ng/ml, respectively. Median PCT values in the gram-negative BC group and gram-positive BC group, respectively, were 6.99 ng/ml and 2.96 ng/ml. Median PCT values in the 'positive hydrothorax culture' group, 'positive ascites culture' group, 'positive bile culture' group, and 'positive cerebrospinal fluid culture' group, respectively, were 1.39 ng/ml, 8.32 ng/ml, 5.98 ng/ml, and 0.46 ng/ml. In all, 357 cases were classified into the 'sepsis' group, 150 of them were classified into the 'severe sepsis' group. Median PCT values were 5.63 ng/ml and 11.06 ng/ml, respectively. CONCLUSIONS: PCT could be used in clinical algorithms to diagnose positive infections and sepsis. Different PCT levels could be related to different kinds of microbemia, different infection sites, and differing severity of sepsis.

[Optimization of the conditions for protein chip preparation].

OBJECTIVE: To define the optimal conditions for preparing protein chips on aldehyde-coated slides. METHODS: The proteins were diluted in PBS containing 40% glycerol and spotted on aldehyde-coated slides. After the spots were dried for 1 hour at room temperature, the slides were stored at 4 degrees Celsius;. Following block and rinse, the slides were used for immunoassay and the results detected with a scanner. Several key factors that might influence the results were tested, including the number of spots, concentration of protein in the spotting solution, time of immobilization and the blocking reagent. RESULTS: Pre-spotting of 10 to 15 spots achieved good homogeneity of the subsequent spots on aldehyde-coated slides. The protein immobilized at 4 degrees Celsius; for 24 to 48 h showed higher fluorescence intensity and clearer images, and the slides blocked with 3% BSA produced the lowest background signal. The concentration of protein in the spotting solution significantly affected the fluorescence intensity. CONCLUSION: To ensure good results in preparing protein chips on aldehyde slides, pre-spotting of 10-15 spots can be necessary followed by immobilization at 4 degrees Celsius; for 24-48 h and 3% BSA blocking.

Immunoassays based on Penicillium marneffei Mp1p derived from Pichia pastoris expression system for diagnosis of penicilliosis.

BACKGROUND: Penicillium marneffei is a dimorphic fungus endemic in Southeast Asia. It can cause fatal penicilliosis in humans, particularly in HIV-infected people. Diagnosis of this infection is difficult because its clinical manifestations are not distinctive. Specialized laboratory tests are necessary to establish a definitive diagnosis for successful management. We have demonstrated previously that a cell wall mannoprotein Mp1p, abundant in P. marneffei, is a potential biomarker for diagnosis of P. marneffei infections. In the present study, we describe immunoassays based on Mp1p derived from the yeast Pichia pastoris expression system. METHODOLOGY/PRINCIPAL FINDINGS: We generated monoclonal antibodies (MAbs) and rabbit polyclonal antibodies (PAbs) against Mp1p expressed in P. pastoris. Subsequently, we developed two Mp1p antigen capture ELISAs which employed MAbs for both the capture and detecting antibodies (MAb-MAb pair) or PAbs and MAbs as the capture and detecting antibodies (PAbs-MAb pair) respectively. The two Mp1p antigen ELISAs detected Mp1p specifically in cultures of P. marneffei yeast phase at 37-40°C and had no cross-reaction with other tested pathogenic fungi. The sensitivities and specificities of the two antigen assays were found to be 55% (11/20) and 99.6% (538/540) for MAb-MAb Mp1p ELISA, and 75% (15/20) and 99.4% (537/540) for PAbs-MAb Mp1p ELISA performed using 20 sera with culture-confirmed penicilliosis, and 540 control sera from 15 other mycosis patients and 525 healthy donors. Meanwhile, we also developed an anti-Mp1p IgG antibody ELISA with an evaluated sensitivity of 30% (6/20) and a specificity of 98.5% (532/540) using the same sera. Furthermore, combining the results of Mp1p antigen and antibody detection improved the sensitivity of diagnosis to 100% (20/20). CONCLUSIONS/SIGNIFICANCE: Simultaneous detection of antigen and antibody using the immunoassays based on Mp1p derived from P. pastoris greatly improves detection sensitivity. The procedures should be useful for the routine diagnosis of penicilliosis.

[Detection of pathogenicity island-associated genes in enterococcal isolates].

OBJECTIVE: To investigate the presence of pathogenicity island (PAI)-associated genes in the enterococcal isolates. METHODS: Using PCR and hybridization methods, PAI-associated genes were detected in 155 enteococcal strains isolated from clinical patients and healthy individuals. RESULTS: Among the 155 enterococcal isolates, 137 (88.39%) carried at least one of PAI-associated genes, namely hyd (positivity rate of 81.94%), psaA (78.06%), nuc (57.42%), esp (53.55%), cylB (52.90%), and gls24-like (38.06%) genes. Expect for esp gene, the other 5 genes showed higher positivity rates in the E. faecalis strains than in the E. faecium strains, and this difference was statistically significant for the genes nuc, cylB, and gls24-like. The positivity rates and the number of these genes in the E. faecalis from clinical isolates were both significantly higher than those in the strains isolated from healthy individuals. CONCLUSION: The data show a wide distribution of the PAI-associated genes among the enterococcal strains, and E. faecalis strains are more likely than E. faecium strains to be positive for the 6 genes, which are present at significant higher rates in the clinically isolated samples than in that from healthy individuals.