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:

1.Urine

2.CSF

3.Blood

4.Semen

5. Effusions: Synovial fluid, Pleural fluid,

Peritoneal fluid, Ascitic fluid, Hydrocele fluid

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.

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 col lected.

AppearanceCauseClear, yellowNormalCloudyBacterial infection Red and cloudy1. Bacterial infection

2. Urinary schistosomiasis

Brown and cloudy1. Black water fever2. Intravascular

haemolysisYellow brown or green brown

1. Acute viral hepatitis2. Obstructive jaundice

Yellow-orange1. Haemolysis2. Hepatocellular

jaundiceMilky-whiteFilariasis

Appearance of Urine

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 .

Laboratory Examination:

@ Collect by a lumbar puncture, and process immediately. If there is delaykeep the fluid at 35-37 °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.

@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 sedi ment for TB meningitis

@ Do India ink capsule stain for C. neoformans

@ Culture on chocolate, Mc Conkey, & blood agar to isolate the bacterial pathogens.

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.

Laboratory Examination:

@Blood is collected before antimicrobial treatment, and at the time of fever. Two speci mens 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.

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.

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

(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.

(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 .

@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