Common bacterial
diseases
Mrs. Dalia Kamal Eldien
MSC in Microbiology
Lecture NO: 5&6
Common bacterial diseases
 Bacterial diseases include any type of illness caused by
bacteria.
 The pathogenesis of bacterial infection includes the
initiation of the infectious process and the mechanisms
leading to the development of signs and symptoms of
bacterial disease.
 Examples to common bacterial diseases, include: Urinary tract infection –UTI Meningitis
 Tuberculosis
 Pneumonia
Common bacterial diseases
 Food poisoning
 Gastritis and gastric ulcers
 Gonorrhea
 Syphilis
 Tonsillitis
 Septicemia
 Puerperal sepsis, ect ……………….
Urinary tract infection(UTI)
 Also known as acute cystitis or bladder infection, is
an infection that affects part of the urinary tract.
 Urinary system consist of kidney, ureters, urinary bladder&
urethra
 When it affects the lower urinary tract it is known as a
cystitis (bladder infection) and when it affects the upper
urinary tract it is known as pyelonephritis (kidney
infection).
Urinary system
Sings& symptoms of UTI
 Symptoms of cystitis (bladder infection) include:
o
o
o
o
o
Either frequent urination or urge to urinate (or both)
Dysuria (painful urination)
Cloudy urine with a strong odor
Blood in urine (hematuria)
Low-grade fever
Sings& symptoms of UTI
 Symptoms of pyelonephritis can vary depending on a
person’s age and may include the following:
o Fever
o Vomiting
o Flank pain (back, side, and groin pain)
o Chills
o Nausea
o Frequent, painful urination
UTI
 Urinary tract infections occur more commonly in women
than men, due the short female urethra.
 In men, the infection is low as a result of antibacterial
activity of prostatic secretions
• Explain why UTI common in female than male?
Common bacterial causing UTI
 Escherichia coli is the commonest urinary pathogen
causing 60–90% of infections.
 UTIs caused by Pseudomonas, Proteus, Klebsiella species
and Staph aureus, are associated with hospital-acquired
infections, often following catheterization or gynaecological
surgery.
 Proteus infections are also associated with renal stones.
Diagnosis of UTI
 The diagnosis of UTI should be CLNICAL, based on
symptoms and signs, and laboratory testing.
 Diagnosis of a urinary tract infection is based on
information& symptoms given by the patient to the
physician
 A physical examination and lab tests complete the
evaluation.
Diagnosis of UTI
 The most important lab test is urinalysis.
 A urine sample will be tested for signs of infection, such
as the presence of white blood cells and bacteria.
 Midstream urine also be "cultured." This means that a
small amount of the urine is brushed on a sterile media in
a plastic plate.
 The plate is incubated for 24 hours , and then examined to
see what kind of bacteria are growing on it.
Plate culture for urine specimen
Antibiotics Sensitivity test
 The isolated bacteria are treated with different antibiotics
to see which works best against them.
 This helps determine the best treatment for the specific
infection.
Antibiotics Sensitivity test
Bacterial meningitis
 The term meningitis inflammation of meninges (membrane
cover the brain and spinal cord) caused by:
a) Neisseria meningitidis: The pathogen is a small, non
motile, encapsulated, aerobic, Gram-negative diplococcus
b) Streptococcus pneumoniae Gram-positive, encapsulated
chain of diplococci
c) Haemophilus influenzae type b. a small, non motile,
encapsulated, Gram-negative rod
Meninges
Bacterial meningitis
 All three bacterial species discussed above enter the body
by respiratory droplets from prolonged contact, such as
coughing, sneezing, or kissing.
 They then colonize the nasopharynx and sinus cavities
 However, should the organism invade into the nonciliated
epithelium and spread to the blood
 Once in the blood, all three pathogens are capable of
crossing the blood-brain barrier.
 The meninges then become inflamed, causing pressure on
the spinal cord and brain.
Sings& Symptoms
o
o
o
o
o
o
Fever
Stiff neck
Headache
Nausea
Vomiting
Sensitivity to bright light
Diagnosis
 Clinically
 Imaging: X-rays and computerized tomography (CT)
scans of the head, chest or sinuses may reveal swelling or
inflammation. These tests can also help your doctor look
for infection in other areas of the body that may be
associated with meningitis.
 Laboratory: The definitive diagnosis of meningitis
requires an analysis of patient cerebrospinal fluid (CSF),
which is collected during a procedure known as lumbar
puncture (spinal tap)
Collection of CSF
Lumbar puncture syringe
Tuberculosis
 Tuberculosis (TB) is caused by Mycobacterium tuberculosis
 It is a small, aerobic, non motile rod whose cell wall
contains a layer of waxy material
 M. tuberculosis enters the respiratory tract in small
aerosolized droplets
 Crowded conditions and poor ventilation contribute to
disease spread.
 TB is chronic disease takes much longer time to symptoms
appear
 Tuberculosis typically attacks the lungs, but can also affect
other parts of the body
Sings& symptoms
o A cough with thick, cloudy, and sometimes bloody mucus
from the lungs (sputum) for more than 2 weeks.
o Loss of appetite
o Unexplained weight loss
o Night sweats
o Fever
o Fatigue
o TB of the kidney may cause blood in the urine
o TB of meninges may cause headache or Confusion
o TB of the spine may cause back pain
o TB of the larynx can cause hoarseness
Diagnosis
• The diagnosis of tuberculosis include:
 Clinical diagnosis
 Radiological diagnosis by Chest Radiograph
 Laboratory diagnosis to isolate the causative bacteria
Mycobacterium tuberculosis bacilli under
microscope
Pneumonia
 The term pneumonia refers to microbial disease of the
bronchial tubes and lungs.
 A wide spectrum of organisms, including viruses, fungi,
and bacterial species, may cause pneumonia.
 Usually acquired by aerosolized droplets
Symptoms of Pneumonia
• Cough (with some pneumonias you may cough up
greenish or yellow mucus, or even bloody mucus)
• Fever, which may be mild or high
• Shaking chills
• Shortness of breath, which may only occur when you
climb stairs
Healthy air way vs. one pneumonic one
Types of bacterial pneumonia
 " Basically, pneumonia can be classified in to :
A- Community acquired pneumonia is the most common
type of pneumonia because you can catch it in public
places such as a school or workplace
B- Hospital acquired pneumonia is more serious and
dangerous than community-acquired pneumonia as the
germs in hospital are more resistant to the drugs given
Diagnosis
Physical Exam
The doctor will listen to the lungs with a stethoscope. If
their pneumonia, the lungs may make crackling, bubbling,
and rumbling sounds, also doctor may hear wheezing.
Chest X Ray or Chest computed tomography (CT) scan
Laboratory tests: sputum& blood specimen send to the
lab to diagnose the causative agent to culture.
Treatment
 Specific treatments depend on the type and severity of
pneumonia, age and the overall health. The options
include:
o Antibiotics: are used to treat bacterial pneumonia. It may
take time to identify the type of bacteria causing your
pneumonia and to choose the best antibiotic to treat it.
o Fever reducers such as Ibuprofen& Paracetamol
o Cough medicine: used to calm the cough so that to can
rest. Because coughing helps loosen and move fluid from
the lungs, it's a good idea not to eliminate your cough
completely.
By this lecture we finish the chapter of
bacteria
Sources for more reading
 Microbiology, Lippincott’s Illustrated Reviews. Cynthia Nau
Cornelissen, Bruce D. Fisher, Richard A. Harvey. Third
edition
 Review of medical microbiology and immunology. Warren
Levinson. Eleventh edition
 District Laboratory Practice in Tropical Countries, Monica
Cheesbrough, Part 2, Second Edition
 Applied Microbiology, Dr. Abd Elwahab M. Abd Elhafz and
Dr. M. A. M. Moubarak, references by Dr. Saad A. Z.
Mahmoud. 1st ed. Cairo, 1996