Laboratory diagnosis and molecular characterization of bacterial bloodstream infections

Bloodstream infections [BSI] represent an important complication in patients receiving chemotherapy for neoplastic diseases. To identify and characterize the isolated bacteria from blood of pediatric cancer patients with fever, blood cultures were done and identification was carried out by conventional methods and API [for Gram negative bacteria], then molecular characterization by Pulsed Field Gel Electrophoresis [PFGE] was done. This study was conducted on fifty pediatric cancer patients with fever. We found that only 22% of patients were positive for BSI, Gram positive bacteria were more commonly isolated than Gram negative bacteria and Coagulase negative Staphylococci [CONS] were the most commonly isolated species. There was a significant association between the presence of neutropenia with the increased incidence of BSI. The analysis of PFGE patterns produced showed identical profiles for most of the isolated bacterial strains. This means that those isolates have a common source of infection and strict infection control measures are needed inside our institude for prevention of HAI especially with those immunocompromised risky patients

Rapid enzyme-linked immunosorbent assay for the diagnosis of human brucellosis in surveillance and clinical settings in Egypt

To optimize and standardize an enzyme-linked immunosorbent assay [ELISA] for rapid diagnosis of human brucellosis in clinical cases identified during a surveillance study for acute febrile illness [AFI]. Serum samples from patients presenting with AFI at 13 fever hospitals across Egypt between 1999 and 2003 were kept frozen at NAMRU-3 and used in this study. The assay was evaluated in 5 subject groups: brucellosis cases confirmed by blood culture [group I, n=202] 87% positive by standard tube agglutination test [TA], brucellosis cases exclusively confirmed by TA [group II, n=218], blood cultures from AFI cases positive for bacterial species other than Brucella [group III, n=103], AFI cases with unexplained etiologies [group IV, n=654], and healthy volunteers [group V, n=50]. All members of groups III-V were negative for brucellosis by TA. Sensitivity and specificity of ELISA for total specific antibodies were >=96% versus 87% for TA as compared to microbial culture, the current gold standard method for Brucella identification. Assessment of Brucella antibody classes by ELISA in random subsets of the 5 groups showed significantly high [p>0.001] levels of anti Brucella IgG [>=81%] and IgM [>=90%] in groups I and II only. The obtained sensitivity and specificity results indicate that our ELISA is more suitable for AFI surveillance and clinical settings than blood culture and TA. The developed assay is also cost-effective, easier to use, faster, and the coated plates can be stocked for at least 8 months, providing a potential for field use and automation