A “clean catch” urine for culture of catheterised
urine specimen must be used to determined the type of bacterial in urine
(Christian, 2006).
urine specimen must be used to determined the type of bacterial in urine
(Christian, 2006).
Urine microscopy
Description of the
appearance of the urine sample must be done, indicating whether the urine is
cloudy, reddish, brown, yellow, orange or milky white. urine which has
unpleasant odour may contain white blood cell, which is indication of bacterial
urinary tract infection. Also reddish urine may be a of result of bacterial
infection (Monica, 2005).
appearance of the urine sample must be done, indicating whether the urine is
cloudy, reddish, brown, yellow, orange or milky white. urine which has
unpleasant odour may contain white blood cell, which is indication of bacterial
urinary tract infection. Also reddish urine may be a of result of bacterial
infection (Monica, 2005).
Significance of urine
microscopy
microscopy
Urine is examine
microscopically as wet preparation to detect: significant pyuria (i.e. white
blood cells in excess of 10 cell/µl (10/µl)of urine, red blood cell yeast
cells, Trichimonas vaginalis motile trophozoites, schistosom haematobium,
bacterial (Monica, 2005). It is generally accepted that a bacterial count of
more than 100,000(105) per millitre of urine is a significant count and it indicates
infection. This is true bacteriauria.a count of less than 100,00(105)
bacteria per millitre is taken to be as a result of contamination and therefore
non- significant or it may be that urine was collected after chemotherapy.
microscopically as wet preparation to detect: significant pyuria (i.e. white
blood cells in excess of 10 cell/µl (10/µl)of urine, red blood cell yeast
cells, Trichimonas vaginalis motile trophozoites, schistosom haematobium,
bacterial (Monica, 2005). It is generally accepted that a bacterial count of
more than 100,000(105) per millitre of urine is a significant count and it indicates
infection. This is true bacteriauria.a count of less than 100,00(105)
bacteria per millitre is taken to be as a result of contamination and therefore
non- significant or it may be that urine was collected after chemotherapy.
Count between 1000 (103) to 10,000 is
doubtful significant because it may be caused by delay delivery of specimen to
the laboratory or severe contamination (Ochie and Kolhtkar, 2007).
doubtful significant because it may be caused by delay delivery of specimen to
the laboratory or severe contamination (Ochie and Kolhtkar, 2007).
Urine culture
Urine culture must be done
if the specimen contains pus cells, bacterial, casts, protein, protein or shows
high alkalinity or high acidity reaction. Pyuria was once considered as a “sure
sign” of bacteriuria. It has been found that many patient with significant
bacteria do not have pyuria or that the presence of pus cell is intermittently
excess (Ochie and Kolhtkar, 2007).
if the specimen contains pus cells, bacterial, casts, protein, protein or shows
high alkalinity or high acidity reaction. Pyuria was once considered as a “sure
sign” of bacteriuria. It has been found that many patient with significant
bacteria do not have pyuria or that the presence of pus cell is intermittently
excess (Ochie and Kolhtkar, 2007).
Appearance of some urinary pathogens on (cled
medium)
medium)
i.
S. aureus: deep yellow of uniform
colonies.
ii.
S.saprophytus and other coagulase
negative staph: yellow to white colonies
iii.
E.coli: yellow (lactose
fermenting) opaque and colonies often with slightly colour centre.
iv.
Klebsiella species: large muciod yellow colonies
or yellow white colonies (Monica, 2005).
Appearance of staphylococous aureus on blood
agar
agar
S. aureus produces yellow to cream
or occasionally white 1 – 2 mm diameter colonies after overnight incubation.
Some strains are beta- haemolytic when grown aerobically. Colonies are slightly
raised (Monica, 2005).
or occasionally white 1 – 2 mm diameter colonies after overnight incubation.
Some strains are beta- haemolytic when grown aerobically. Colonies are slightly
raised (Monica, 2005).
Gram’s staining
Gram starring reaction is
used to identify pathogen in specimen (Direct gram) and culture (Indirect gram)
by their gram’s reaction (Gram positive or Gram negative organism) and their
morphology. Pus can also be identified in gram sinear.
used to identify pathogen in specimen (Direct gram) and culture (Indirect gram)
by their gram’s reaction (Gram positive or Gram negative organism) and their
morphology. Pus can also be identified in gram sinear.
Gram’ positive bacterial stains dark-purple with
crystal violet, while gram-negative organism stains red with the counter stain
neutral red after decolorizing with acetone. Gram negative organism are red because
after being stained with crystal violet they are decolorized by acetone or
ethanol and they take up the red colour of the counter neutral red. Gram positive
bacterial includes all staph species,
strep species, clostridium species, corynebactenum
diphtheriae, Gram negative bacterial includes neisseria species, haemophilus
influerizae, salmonella species, shigella species,
klebsiella species (Monica,2008).
crystal violet, while gram-negative organism stains red with the counter stain
neutral red after decolorizing with acetone. Gram negative organism are red because
after being stained with crystal violet they are decolorized by acetone or
ethanol and they take up the red colour of the counter neutral red. Gram positive
bacterial includes all staph species,
strep species, clostridium species, corynebactenum
diphtheriae, Gram negative bacterial includes neisseria species, haemophilus
influerizae, salmonella species, shigella species,
klebsiella species (Monica,2008).
Catalase Test
This test helps to differentiate streptococci from staphylococci. The enzymecatalase is produced only by staphylococcus species and not streptococcus species catalase acts as a catalyst in breaking
down of hydrogen peroxide to form oxygen and water 2 H2O2
2 H2O + O2when the organism containing catalase comes in contact with hydrogen peroxide,
bubbles of oxygen are given off ( Ochei and Kolhtkar, 2007).
Coagulase test ( confirmatory test for S.
aureus)
aureus)
This test is used to differentiate S.aureus from other staphylococcus. The enzyme coagulase
causes plasma to clot by converting fibrinogen to fibrin. Coagulase test is considered as pathogenicity test for staph. Aureus. Two types of coagulase
enzymes is produced by staph aureus:
causes plasma to clot by converting fibrinogen to fibrin. Coagulase test is considered as pathogenicity test for staph. Aureus. Two types of coagulase
enzymes is produced by staph aureus:
i.
Free Coagulase:
This convert fibrinogen to fibrin by first activating coagulase reacting factor (C.R.F.). This coagulase is detected by the formation of clot in test tube in
which bacterial broth is mixed with plasma. The free coagulase is released in the surrounding medium.
Free Coagulase:
This convert fibrinogen to fibrin by first activating coagulase reacting factor (C.R.F.). This coagulase is detected by the formation of clot in test tube in
which bacterial broth is mixed with plasma. The free coagulase is released in the surrounding medium.
ii.
Bound Coagulase:
Bound coagulase convert fibrinogen to fibrin with the absence
of coagulase reacting factor. It is
detected by clumping in the slide test. The bound coagulase is associated with bacterial cells. The free coagulase is the most constantly
produced extracellular products. It is usually recommended to do tube coagulase on all slide coagulase negative staphylococci (Ochei
and Kolhtkar, 2007).
Bound Coagulase:
Bound coagulase convert fibrinogen to fibrin with the absence
of coagulase reacting factor. It is
detected by clumping in the slide test. The bound coagulase is associated with bacterial cells. The free coagulase is the most constantly
produced extracellular products. It is usually recommended to do tube coagulase on all slide coagulase negative staphylococci (Ochei
and Kolhtkar, 2007).
