I have collected almost 160 samples from a tertiary hospital from children
Dear Nithu,
Pneumonia and meningitis are clinical diagnosis that can be caused by a great number of microbes. S. pneumoniae, although common, isn't the only etiological agent of these diseases.
Nevertheless, S, pneumoniae is a very fragile bacteria. A single antibiotic dose prior to cultures can prevent its isolation from biological products. Have you tried alternative methods, such as serology or molecular biology?
S. pneumoniae cultures need blood agar plates and CO2 Inkubation. The incubation should not be longer than 24h at 35-37 °C. The colonies have a typical autolysis-zone in the middle. They can not be recultured after too long incubation at 37°C. They don´t like low temperature like in a fridge (4°C). If you have stored the liquor and sputum or BAL in ther fridge it could be the reason.
Dear Alexandre,
For my study we are taking invasive samples but most of the cases have got antibiotics from a primary centre. I am doing Binax antigen for CSF but results are negative. I have not tried any molecular tests as for blood specificity matters if you are doing PCR. Do you have any other suggestive molecular techniques?
Dear Heidelinde,
We are using sheep blood agar plates and CO2 incubator. We are looking for inasive pneumococci only.
Hi
Lets me try to answer , i was involved in Meningitidis project at CMC vellore for more than 3 years and what i feel is below
as earlier told S, pneumoniae is a very fragile bacteria, though there is bacteria density in sample there are few factors of which they do not grow invitro
let me list out
1. time span for sample arrival to lab is most crucial factor and thats what we experienced at our surveillance
2. media nutrition , we even experienced difference in media of two company and got better isolation with one of them and made in practise to use than regularly.
3. you can increase percentage of blood in media offc course.
4. technique of plating, as most of people come with antibiotic treatment in advance so when you plate the sample just do not spread it there and there put a drop let it dry so antibiotics get absorbed in media locally and then spread it you will get better result
and so many other small small factors are there which we made in practise and we saw number of isolation was jumped in span of year....
Bianx is really good enough and sensitive , we also used PCR and Real time PCR
- Badges
- Science topic
- Similar topics
- Medicine
- Disease
- Infectious Diseases