False identification of other microorganisms as Staphylococcus aureus in Southern Nigeria

Purpose: Staphylococcus aureus is the causative agent of many infections and the advent MRSA has drawn much attention to it. However, some organisms have been noted to be wrongly identified as S. aureus through phenotypic identifications leading to wrong treatment of infections. This study is therefore undertaken to evaluate the rate of false identification of other organisms as S. aureus in Southern Nigeria. Methods: 507 microorganisms which have been previously identified as S. aureus in 8 States in Southern Nigeria through characteristic morphology on blood agar, Gram staining, growth and fermentation on Mannitol Salt Agar and coagulase formation were collected. All the isolates were identified in this study through sequencing of 16S rRNA and detection of spa gene. The percentages of true and false identities were determined. Results: Of the 507 isolates previously identified as S. aureus, only 54 (11 %) were confirmed as S. aureus while the rest were coagulase negative Staphylococci (85 % misidentification rate), Bacillus sp. (12 % misidentification rate), and Brevibacterium sp. (3 % misidentification rate). Conclusion: A high rate of false positive identification of S. aureus which could lead to the misuse of antibiotics in emergency situation has been identified in this study. The use of standard methods for the identification of S. aureus at all times is highly recommended.

Role of cytokines in Trypanosoma brucei-induced anaemia: A review of the literature

Background Anaemia is an important complication of trypanosomiasis. The mechanisms through which trypanosomal infection leads to anaemia are poorly defined. A number of studies have implicated inflammatory cytokines, but these data are limited and inconsistent. In this article, we reviewed the published literature on cytokines associated with Trypanosoma brucei infections and their role in the immunopathology leading to anaemia. Methodology Articles were searched in PubMed through screening of titles and abstracts with no limitation on date of publishing and study design. Articles in English were searched using keywords “African trypanosomiasis”, “sleeping sickness”, “Trypanosoma brucei”, in all possible combinations with “anaemia” and/or “cytokines”. Results Twelve articles examining cytokines and their role in trypanosomeinduced anaemia were identified out of 1095 originally retrieved from PubMed. None of the articles identified were from human-based studies. A total of eight cytokines were implicated, with four cytokines (IFN-γ, IL-10, TNF-α, IL-12) showing an association with anaemia. These articles reported that mice lacking TNF-α were able to control anaemia, and that IFN-γ was linked to severe anaemia given its capacity to suppress erythropoiesis, while IL-10 was shown to regulate IFN-γ and TNF-α, providing a balance that was associated with severity of anaemia. IFN-γ and TNF-α have also been reported to work in concert with other factors such as nitric oxide and iron in order to induce anaemia. Conclusion IFN-γ, IL-10, and TNF-α were the three major cytokines identified to be heavily involved in anaemia caused by Trypanosoma brucei infection. The anti-inflammatory cytokine, IL-10, was shown to counter the effects of proinflammatory cytokines in order to balance the severity of anaemia. The mechanism of anaemia is multifactorial and therefore requires further, more elaborate research. Data from human subjects would also shed more light.