Evaluation of procalcitonin, C-reactive protein, interleukin-6 & serum amyloid A as diagnostic biomarkers of bacterial infection in febrile patients.

Background & objectives: Early identification of bacterial infection in patients with fever is important for prompt treatment. However, the available parameters such as C-reactive protein (CRP) and leukocyte counts are not very specific. This study was aimed to assess the diagnostic value of procalcitonin (PCT), CRP, interleukin-6 (IL-6) and serum amyloid A (SAA) for bacterial infection in febrile patients. Methods: Serum samples were collected from febrile patients between January and December 2012 and processed for blood cultures. PCT, IL-6, CRP and SAA levels were measured. The patients were divided into three groups according to the final diagnosis: bacteraemia group (group1), bacterial infection with negative blood culture (group 2) and non-bacterial infection group (group 3). Results: There were significant (P<0.05) difference in the levels of PCT, CRP, IL-6 and SAA among the three groups. The PCT levels of patients with gram-positive bacterial infections were lower than gram-negative bacterial infections (0.53 vs 2.13, P < 0.01). The best cut-off value to detect bacterial infections was 0.26 ng/ml for PCT. PCT, CRP, IL-6 and SAA had areas under the curve of 0.804, 0.693, 0.658 and 0.687, respectively. Interpretation & conclusions: Our results showed PCT as a valuable marker of bacterial infections in febrile patients. PCT was superior to CRP, IL-6 or SAA in the early identification of bacterial infection. More prospective and large scale studies are warranted to confirm these findings.

PCR versus serology for diagnosing Mycoplasma pneumoniae infection: A systematic review & meta-analysis.

Background & objectives Diagnosis for Mycoplasma pneumoniae usually relies on serological tests. PCR technology has some advantages but also limitations. The optimal selection for these tests still needs discussion. This paper reviews the overall diagnostic accuracy of PCR versus serological assays for diagnosis of M. pneumoniae infections and to identify factors associated with heterogeneity of results. Methods: MEDLINE and Embase databases were searched. Articles meeting the selection criteria were retrieved for data collection and analysis. Studies were assessed for methodological quality using QUADAS. Hierarchial summary receiver operating characteristic (HSROC) model was used to estimate summary ROC curve. Results: Initial meta-analysis showed a summary estimate of sensitivity (SEN) 0.62 (95% CI, 0.45-0.76), and specificity (SPE) 0.96 (95% CI, 0.93-0.98). Subgroup analyses were performed to identify factors associated with heterogeneity. For different gene targets, reference standards, subjects (children or adults) and different PCR types, these aspects can generate results of heterogeneity. The 16s rDNA target and adult subjects and real-time PCR may have better test results for PCR. Interpretation & conclusions Commercial PCR tests generated consistent results with high specificity but a lower and more variable sensitivity. The findings suggest commercial PCR tests having superiorities in diagnosing M. pneumoniae infections but still cannot replace serology. PCR plus serology could be good screening tests for reliable and accurate diagnosis of M. pneumoniae.

Disseminated penicillium marneffei infection with fungemia and endobronchial disease in an AIDS patients in China

To present a rare Chinese case ofdisseminated Penicilliummarneffei infection with fungemia and endobronchial disease in an AIDS patient. A 26-year-old policeman who had resided in Guangxi Province, China, for 3 years presented to his county hospital with a 2-month history of high fever and cough. A provisional diagnosis of pulmonary tuberculosis [TB] was made. Accordingly, the patient was treated with anti-TB drugs for 1 month but with no clinical improvement; he was then referred toWest China Hospital. Blood and bone marrow cultures as well as a bronchoscopic biopsy were positive for P. marneffei. A confirmatory serologic test for HIV was positive. A combination therapy with amphotericin B and itraconazole was instituted, and the patient responded well to treatment. This case showsendobronchial involvement caused by an emerging fungal microorganism. HIV-positive patients with a history of residence in or travel to southern China and a clinical presentation suggestive of TB but responding poorly to anti-TB treatment may have P. marneffei infection