1. Body Fluids and Bone Marrow Infections
@ Body fluid (or biofluids) are liquids originating
from inside the human body.
@ Body fluids analyzed in the laboratory are:
Urine
CSF
Blood
Semen
5. Effusions: Synovial fluid, Pleural fluid,
Peritoneal fluid, Ascitic fluid, Hydrocele fluid

2. URINE Possible Pathogens:
@ Gram positive: Enterococci, S. saprophyticus
Haemolytic streptococci
@ Gram negative: E. coli, Proteus, Pseudomonas
Klebsiella, Salmonella, N. gonorrhoeae,
@ Others: Myco. Tuberculosis, Leptospira interrogans
Chlamydia, Mycoplasma, Candida species
Commensals:
@ Acinetobacter, diphtheroids, S. epidermidis, yeasts,
and Mycobacterium smegmatis.

3. Collection of urine if TB is suspected:
@ Collect first entire urine passed on three
successive mornings.
@ The container used must be clean, dry,
leak-proof & large to contain all urine
@ It need not be sterile because urine is
decontaminated before culture.
@ The urine is stored at 4°C until all three
urines have been col­lected.

4. Appearance of Urine Appearance Cause Clear, yellow Normal Cloudy
Bacterial infection
Red and cloudy
Urinary schistosomiasis
Brown and cloudy
Black water fever
Intravascular haemolysis
Yellow brown or green brown
Acute viral hepatitis
Obstructive jaundice
Yellow-orange
Haemolysis
Hepatocellular jaundice
Milky-white
Filariasis

5. Cerebrospinal Fluid
Possible Pathogens
@ Gram positive: S. pneumoniae, S. aureus,
S. agalactiae, Listeria, Bacillus anthracis
@ Gram negative: N.meningitidis, E. coli,
Ps. Aeruginosa, Proteus, Salmonella,
Flavobacterium, Bacteroides. H.influenzae
@ Others: Myco.TB, T. pallidum, Leptospira
@ Viruses: ECHO, Coxsackiae, & Poliovirus
@ Fungi: Cryptococcus neoformans.

6. Laboratory Examination:
@ Collect by a lumbar puncture, and process
immediately. If there is delaykeep the fluid
at °C.
@ Take 2 samples: first to be used for culture,
and the second for microscopy.
@ A viral transport medium is used for viruses
@ Check if CSF is clear, cloudy, purulent,
bloody, yellow-red, or contains clots.
@ Clotted CSF is found in pyogenic meningitis.

7. @ In TB meningitis, CSF forms a skin spider
web clot.
@ Count neutrophil and lymphocytes cells
using a Neubauer ruled chamber.
@ Gram smear: Fix smear with methanol and
look for pus cells, bacteria, and fungi
@ Do ZN on CSF sedi­ment for TB meningitis
@ Do India ink capsule stain for C. neoformans
@ Culture on chocolate, Mc Conkey, & blood
agar to isolate the bacterial pathogens.

8. Blood and Bone Marrow Possible Pathogens:
@ Gram negative: Salmonella species, Brucella,
H. influenzae, Ps. Aeruginosa, Klebsiella,
E. coli, Proteus, Bacteroides, N. meningitidis
Y. pestis
@ Gram positive: S. aureus, S. viridans,
S. pneumoniae, S. pyogenes, Enterococci,
anaerobic streptococci, C. perfringens
@ Fungi: C. albicans, H. capsulatum
@ Others: Leptospira, Borrelia.

9. Laboratory Examination:
@ Blood is collected before antimicrobial
treatment, and at the time of fever. Two
speci­mens are collected at different
times aseptically.
@ Bone marrow is aspirated by a pathologist.
@ Culture in one of the following media:
1. Tryptone soya diphasic medium, where
bacteria grow on the slope, hence no need
for subculture. It contains tryptone soya
agar slope, a tryptone soya broth, liquoid,
and p-aminobenzoic acid.

10. 2. Thioglycollate broth medium consisting of
nutrient broth, and thioglycollate. It is
suitable for both anaerobes and aerobes.
@ Pour plate blood culture:
This is done by adding 3 ml blood to 20 ml of
molten nutrient agar, mixing, and pouring in a petri dish. Plate is incubated at 35-37°C overnight.
@ Do dark-field preparation for Leptospira.
@ Examine a Gram smear
@ Subculture on blood, chocolate, and
Mc Conkey agar media.

11. Effusions @ An effusion is a fluid collecting in a body cavity as:
# An exudate (due to infection)
# A transudate (without infection)
@ They include: Hydrocele, Synovial, Pleural,
Pericardial, and Ascitic fluids.
Commensals: Body fluids have no normal flora.
Possible Pathogens
(1) Hydrocele Fluid
Occasionally Wuchereria bancrofti microfilariae

12. (2) Synovial Fluid
@ Gram positive: S. aureus, S. pyogenes,
S. pneumoniae, Actinomycetes, Myco. TB
@ Gram negative: N. gonorrhoeae, E. coli,
N. meningitidis, H. influenzae, Bacteroides
Brucella, Salmonella, Ps. aeruginosa, Proteus
(3) Pleural and Pericardial Fluids
@ Gram positive: S. aureus, S. pneumoniae,
S. pyogenes, Actinomycetes, Myco. TB
@ Gram negative: H. influenzae, Bacteroides,
Pseudomonas, Klebsiella, enterobacteria,
@ Viruses: Coxsackie B virus.

13. (4) Ascitic Fluid
@ Gram negative: E. coli, Klebsiella,
Enterobacteria, Pseudomonas, Bacteroides
@ Gram positive: Enterococci, S.pnemoniae S. aureus, S. pyogenes, S. agalactiae, S. viridans, C. perfringens, Myco. TB
@ Candida species
Laboratory Examination:
@ Effusions are aspirated by a physician in tubes containing anticoagulant & transported
in a thioglycollate broth.

14. @ Describe appearance of effusion: Colour,
clear, cloudy, purulent, clotting, or bloody
@ A transudate is yellowish, clear, unclotted
@ An exudate is purulent, cloudy, or bloody
@ Do Gram and ZN stains for exudates
@ Count the number of WBC in the effusion
(polymorphs and lymphocytes).
@ Culture the effusion after centrifugation on chocolate agar, blood agar (anaerobic), Mc Conkey agar, & LJ slope if TB suspected