Dr.Taghreed Khudhur Mohammad
Lab. 7 / 2015
Morphology of bacteria
Bacterial shape:
Bacteria can be classified into the following types according to their shape of
the cells:
a. Oval or spheroid called coccus  cocci.
b. Rod or cylindrical called bacillus  bacilli.
c. Curved or comma shape.
d. Spiral and coil shaped (spirochactes).
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After binary fission the daughter cell remains attached to the parent cell and
fission occurs again before separates so the bacterial can be classified due to
their shape and aggregation and arrangement to:
I. Cocci (coccus)
a) Single like Micrococcus. ‫مفردة‬
b) Pairs like Diplococcus. ‫مزدوجة‬
c) Chains like Streptococcus. ‫سلسلة‬
d) Groups of four (tetra) like Peptococcus tetracocci. ‫مجاميع رباعية‬
e) Groups of eight (cubical paekat) like Sarcina. ‫مجاميع ثمانية‬
f) Clusters (random clumps) like Staphylococcus. ‫عنقودية‬
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2. Kidney shape like Neisseria. ‫تشبه الكلى‬
3. Cocco-bacilli like Brucilla , E. coli . ‫عصوي كروي‬
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II. Rod or cylinder ‫عصية‬
1. Bacilli(bacillus):‫عصيات‬
a. Single  Salmonella
b. Pairs  Diplobacilli.
C. Cahins  Bacillus.
2. Chinese latter  Corynebacterium.
3. Group of cigarettes Mycobacterium
4. With curved end E. coli.
5. Cuneiform bundle  Mycobacterium
With or without spores.
III. Comma shape (curved) …..
Vibrio ‫ضمات الكوليرا‬
IV. Spiral ‫ حلزونية‬ Treponema ‫السفلس‬
Quiz1
Classify bacteria according to shape.
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Staphylococcus aureus
Diagnosis of Staphylococcus aureus ‫تشخيص المكورات‬
‫العنقودية‬
Clinical samples : ‫النماذج السريرية‬
A- Direct microscope
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Culture the samples on culture media :
‫زرع النموذج على االوساط الزرعية‬
Beta haemolysis on blood agar
Mannitol salt agar ( yellow for Staphylococcus aureus , fermenter)
( Pink for Staphylococcus epidermedis , non-fermenter)
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