3,084 research outputs found
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]
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
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
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