‫بسم هللا الرحمن الرحيم‬
2013-2014
L/O/G/O
Diagnostic Medical Microbiology-Laboratory Manual
Body Fluid Culture
 Aim of the test
Isolate and identify pathogenic organisms from normally sterile
body fluids and perform sensitivity test
 Types of specimen
Aseptically aspirated body fluid (e.g., , synovial, peritoneal fluid).
 Criteria of specimen rejection
Inappropriate specimen transport device; mislabeled specimen;
unlabeled specimen; specimen received after prolonged delay
(usually more than two hour); specimen received in expired
transport media.
Infection Of Sterile Body Fluid
all body fluid are sterile
Common Pathogenic of Precarditis And Myocarditis
Mycoplasma pneumoniae
Chlamydia trachomatis
Mycobacterium tuberculosis
Staphylococcus aureus
Streptococcus pneumoniae
Enterobacteriacae and other gram negative Bacilli
Fungi
Pleural Fluid
Staphylococcus aureus
Streptococcus pneumoniae
Haemophilus influenzae
Enterobacteriacae
Pseudomonas spp.
Anaerobic bacteria
Mycobacterium tuberculosis
Coccidoides immitis
Actinomyces spp.
Aspergillus spp.
Candida spp.
Cryptococcus neoformans
Histoplasma capsulatum
Bones and joints
Staphylococcus aureus
Streptococcus pyogenes
Haemophilus influenzae
Streptococcus pneumoniae
Enterobacteriacae
Mycobacterium spp
Neisseria gonorrheae
Peritoneal fluid
Streptococcus pneumoniae
Group A streptococci
Enterobacteriacae
Other gram negative bacilli
Staphylococci
Neisseria gonorrheae
Chlamydia trachomatis
Fungi
Coccioides immitis
Candida spp
Pre specimen processing
 Who will collect the specimen
 Physician
 Quantity of specimen
 1-5 mL is adequate, a larger quantity of fluid is better.
 Time relapse before processing the sample
 Body fluids should be treated as CSF specimens and
should processed immediately.
 Storage
 Maintain specimen at room temperature. Do not
refrigerate.
Specimen processing
Specimen processing
 Body fluids for culture should be concentrated by either
filtration or high speed centrifugation.
 Filtration of fluid through a 0.45 micrometer poresize
membrane filter allows a greater volume of fluid to be processed
and usually yield better results, then the filter should be cut
aseptically into pieces, one of which is placed on chocolate agar
for incubation in 5% carbon dioxide, one on MacConkey agar, on
blood agar plate for aerobic incubation, and the last on a blood
agar plate for anaerobic incubation.
Specimen processing
 If fluid has been concentrated by centrifugation, the resulting
sediment should be inoculated to an enrichment broth, blood,
chocolate and MacConkey agars.
 All fluids should be processed for direct microscopic
examination, in general if one organism is seen per oil
immersion field at least 105 organisms per milliliter of
specimen are present.
 Specimens for fungi should be examined by direct wet
preparation or by preparing 10% KOH for visualization of
fungi element from a wet preparation.
 Acid Fast stain for Mycobacterium spp.
Post specimen processing
 Interfering factors:
 Patient on antibiotic therapy.
 Improper sample collection.
 Result reporting:
 Report Gram stain, KOH, and AFS finding as an initial report.
 Report the isolated pathogen and its sensitivity pattern as a final
report.
 Turn around time:
 Gram stain and wet mount results should be available 1 hour
after specimen receipt.
 Isolation of a possible pathogen can be expected after 2-4 days.
 Negative culture will be reported out 1-2 days after the receipt
of the specimen.
L/O/G/O
Any Questions ?