Oral health status and behaviours of preschool children in Hong Kong.

published_or_final_versio

Carriage of meticillin-susceptible and -resistant Staphylococcus aureus by medical students in Hong Kong

Letter to the Editorpostprin

Klebsiella pneumoniae necrotizing fasciitis associated with diabetes and liver cirrhosis [9]

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Reply to Bassetti et al.

published_or_final_versio

Cellular signaling pathways of matrix metalloproteinase gene expression by Pseudomonas aeruginosa-infected human bronchial epithelial cells

Research Dissemination Reports - supported by funds (Research Fund for the Control of Infectious Diseases)published_or_final_versio

Anti-inflammatory effects of fluticasone in bronchiectasis

published_or_final_versio

The relationship between sputum microbial load and leucocyte count in stable bronchiectasis

published_or_final_versio

Effects of chelators (desferal, deferiprone & deferaairox) on the growth of klebsiella and aeromonas isolated from transfusion dependent thalassemia patients

Poster Presentation (Doctor’s Session)Infection is among the leading causes of death for thalassemia major patients. The known predisposing factors of infection include prior splenectomy, iron overload and use of iron chelator such as desferal (desferrioxamine). While encapsulated organisms frequently found in splenectomized patients were readily controlled by prophylactic vaccination and vigilant antibiotic treatment, ferrophilic organisms such as Yersinia and Klebsiella remains common among Thalassemic patients. The inductive iron overloaded environment favours the growth of these organisms but their growth is also affected by the environment temperature. For example, Yersinia infection is more prevalent in temperate regions and Klebsiella infection is commonly found in subtropical areas. Furthermore, the use of iron chelator in the form of desferal further aggravates the risk of Yersinia infection. It is because the iron membrane transport protein siderophore found in desferal can be adopted by the bacteria for iron acquisition. However, oral chelators such as deferiprone do not enhance growth of Yersinia in vitro or in vivo. In order to find out whether such observation can be extended to Klebsiella and Aeromona infection, in vitro culture assay using Klebsiella pneumoniae and Aeromonas hydrophila obtained directly from our transfusion dependent thalassaemic patients were performed. The growth rates of the bacteria under iron rich, iron poor with or without different chelators were assessed. The growth rates were analyzed by both: (1) optic density of bacterial broth; and (2) colony count by bacterial agar plate. We found that the growth of Klebsiella was marginally enhanced by desferal in vitro when compared to Yersinia. Such unfavourable effect was not found in either deferiprone or deferasirox in vitro. On the other hand, the growth of Aeromonas was not affected by the presence of any of the 3 chelators. Therefore, we suggested that factors other than desferal may account for the increase prevalence of Klebsiella and Aeromonas infection among Asian thalassemic patients. It also suggests that oral chelators are safe for thalassemic patients during febrile illness. Unlike desferal, withholding iron chelator during infectious period may not be mandatory. But care has to be exercised especially for patients on deferiprone, since neutropenia has to be ruled out during febrile illness. This project was supported by the Children's Thalassaemia Foundationspublished_or_final_versio

Bacteremia caused by staphylococci with inducible vancomycin heteroresistance

The clinical significance of bacteremia due to vancomycin- heteroresistant staphylococci and a rapid laboratory screening method were examined; 203 strains of staphylococci isolated from patients with clinically significant bacteremia were screened by the disk-agar method with use of vancomycin-salt agar to demonstrate satellitism around an aztreonam disk as well as by conventional population screening. Eighteen isolates (three Staphylococcus aureus and 15 coagulase-negative staphylococci) were shown to be heteroresistant to vancomycin. A case-control clinical study showed that the interval between admission and bacteremia, admission to the intensive care unit, prior use of vancomycin and/or β-lactams, and isolation of methicillin-resistant staphylococci were significantly more common among patients with bacteremia due to staphylococci with heteroresistance to vancomycin; these patients had an overall mortality of 44.4%. The use of vancomycin and admission to the intensive care unit were independently significant risk factors on multivariate analysis. Vancomycin heteroresistance is inducible by salt and β-lactams. Indiscriminate sequential use of β-lactams and glycopeptides may facilitate the emergence of glycopeptide resistance.published_or_final_versio

Streptococcus pneumonia serotype 19A bacteremia in a child fully immunized with 10-valent pneumococcal conjugate vaccine

postprin