CULTURE OF NORMALLY STERILE FLUIDS
Lusubilo Malakbungu(BMLS)Lusu2012
Normally sterile Fluids
These are fluids that do not contain commensals. Any marked presence of commensals can lead to progression of disease in these fluid and site in particular.
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Some diseases occuring in normal sterile sites Amnionitis-inflamation of the amnion(fetal
sac).Due to contamination of vaginal flora or instrumentation during antenatal medical procedures.
Pericaditis-inflamation of the pericardium(membrane enveloping the heart).
Peritonitis-inflamation of the peritoneum. Empyema-collection of pus in pleural
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• Septic athritis- pyogenic infection of a joint. Spread by haematogeneous spread.
• Bursitis-inflamation of bursa(small fluid filled sac of fibrous tissues lined with synovial membrane)
• Meningitis-inflamation of the meninges in the brain. Agents can be Haemophilus influenza, Streptococcus pneumoniae.Neisseria meningitidis.
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CULTURING PROCEDURES FOR
SOME NORMAL STERILE FLUIDS
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1.Cerebral Spinal Fluid Collection should be done by
experienced personnel. 5-10ml of CSF should be collected in
two sterile tubes. Disinfection of the skin is mandatory. Cells of CSF disintergrate rapidly,so
they should be processed immediately without delay.
Lumbar puncture done between L3 and L4 Lusu2012
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. If transport to laboratory is not
possible,inoculate CSF aseptically into Trans-Isolate (T-I)Medium and held overnight at 35C
MACROSCOPIC
Cloudy appearance give a clue of pyogenic infections.
Gram staining
CSF should be centrifuged and the sediments smeared for staining.
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CULTURE The drop of sediments after
centrifugation is used for culture. MEDIA:Blood agar,Chocolate
Agar(Tryptone Soy Agar) .Suspected organisms for this culture include N.meningitidis,H.influenza,S.pneumoniae.
-SDA-used for any clue of yeast cells in gram stain. Lusu2012
. MCA-when neonatal meningitis is
suspected,for isolating Escherichia coli also Listeria monocytogenes
RESULTS
Colonies could be of:Neisseria meningitidis(in Blood Agar & chocolate agar)
S.pneumoniae,H.influenza(CA),Cryptococcus neoformans(SDA).
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Confirmation of coloniesH.Influenzae will grow on CA and satellite
colonies in the vicinity of staphylococcus streak.
H.Influenza type b-antiserum slide agglutination.
On CA rapid oxidase positive is suggested to be meningococci.
N.Meningitidis antisera(A,B,C) in slide agglutination
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OTHER STERILE SITES Pericardial effusion
This infections pericaditis can be:- Purulent caused by bacteria. Benign can be due to viruses Granulomatous which are caused by
mycobacterium tuberculosis.
Wide range of bacteria isolated for purulent include Streptococcus spp,Neisseria spp,Haemophilus.
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BONE MARROW
Should be inoculated into commercially available Nutrient broth(e.g Brain-Heart infusion broth or TSB)
Common isolate is S.aureus.
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OTHER EFFUSIONS
Synovial Pleural Ascitic (peritoneal)
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Collection
Is done by a well trained medical officer.
After aspiration ,aseptically dispense the fluid as follows;
2-3ml into a dry,sterile,screw-cap tube or bottle to observe for clotting.
9 ml into a screw-cap tube or bottle which contains 1ml of sterile tri-sodium citrate, mix well for anticoagulation.
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Microscopic Examination
Gram smear-look for pus cells and bacteria.
Ziehl-Neelsen
Look for AFB
Wet preparation for crystals:
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CULTURE Blood agar (incubate aerobically) Chocolate agar(incubate in C02 MacConkey agar
Incubate aerobically.
For suspected Tuberculosis-required facilities of tuberculosis should be used.
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Report culturesLook particularly for
S.aureus,s.pyogenes,s.pneumoniae,H.influenzae,Neisseria spp,Enterobacteria.
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references
Isolation of Agents from Normally Sterile Sites;CDC covers 2003.
Investigations of Fluid from Normally sterile sites; Issued by Standards Unit, Department for Evaluations, Standards and Training,Centre for Infections.
Cheesebrough M.District Laboratory Practice in Tropical Countries, Part 2 Second Edition Lusu2012
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