BACTERIAL INFECTIONSFatima AlAwadh

objectives• Define and Classify Bacteria.• State the different ways of bacterial infections spread.• Mention the risk factors for bacterial infections.

Definition of Bacteria• Bacteria are relatively simple in structure. They are prokaryotic organisms-simple unicellular organisms with no nuclear membrane, mitochondria, Golgi bodies, or endoplasmic reticulum-that reproduce by asexual division.

Bacterial Classification• Bacteria can be classified by their macroscopic and

microscopic appearance, by characteristic growth and metabolic properties, by their antigenicity, and finally by their genotype.

Bacterial Classification

• Growth characteristics; resist certain antibiotics, ferment specific sugars, to lyse erythrocytes, or to hydrolyze lipids.

• Colony characteristics; color, size, shape, and smell

Macroscopic

• Size• Shape • Configuration of the organism (cocci,

rods, curved, or spiral) • Retain the Gram stain

Microscopic

Gram Stain

Is the primary mean to distinguish bacteria.

Allows clinicians to distinguish between the two major classes of bacteria.

Is a rapid, powerful, easy test.

Gra

m P

ositi

ve cocci

Staphylococcus

Streptococcus

Enterococcus

bacilli

Spore-forming

Non-sporeforming

Acid-fast

Gra

m N

egat

ive

cocciNeisseria

Moraxella catarrhalis

Bacilli

Enterobacteriaceae

Pseudomonas, Stenotrophomonas

, Burkholderia

Stenotrophomonas

coccobacilli

Moraxella

Acinetobacter

Haemophilus

How does bacteria spread ?

Sneezing and

Coughing (air).

Interaction with

tainted food,

surfaces, and water.

Physical contact.

Exchange of bodily

fluids.

Interaction with

contaminated living

being.

Infections Risk Factors

• medical risks• past medical history • family history • current treatment

• social risks• lifestyle• travel history• occupation