ayham omar mohammad malas - humsc · ayham omar 10 . scientific team – يملعلا قيرفلا...
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Mohammad Malas
Ayham Omar
10
SCIENTIFIC TEAM 1 –الفريق العلمي
بسم الله الرحمن الرحيم
Pseudomonas Aeruginosa
Very successful hospital pathogen (very important in hospital
environments), because:
It infects immunocompromized patient.
It shows resistance to most antibiotics.
Usually causes hard to treat nosocomial infections (hospital
infections).
Pseudomonas Aeruginosa
Lecture 10
Date : 15/Nov./2020
كلام الدكتور: الأسود
السلايد: الأزرق
شرح أو توضيح خارجي: الأخضر
SCIENTIFIC TEAM 2 –الفريق العلمي
People at risk include:
Hospitalized patients
Immuno-compromised persons can cause very severe life
threatening infection.
Healthy individuals mild infection.
CF patients can cause severe chronic infection in CF patients
like, pneumonia and chest infection.
- CF patients: cystic fibrosis patients (مرضى التليف الكيسي) .
Ecological factors (which make Pa so successful):
Pa is primary a nosocomial pathogen.
It is ubiquitous water and soil organism.
Survive well in domestic environments like contact lenses and
solutions, and in hospital (food, cut flowers, sinks, toilets, floor
mops, respiratory therapy (respirator) and dialysis equip, and
even in some disinfectant solutions)
Rarely it can be a part of normal flora in healthy individuals
Importance of prevention:
How the ecological factors are important in risk prevention?
- If we know where we can find Pa (by knowing the ecological
factors) we can prevent patients from infection.
لأنه في عليها كثير من هذه البكتيريا، مثلً يعني بنمنع وجود الورود والخضار في وحدة الحروق -
.واذا وصلت للمريض رح تسببله عدوى شديدة
SCIENTIFIC TEAM 3 –الفريق العلمي
Pa is found almost everywhere in hospital, it is even found in
disinfectant (الي بيستخدموه للتعقيم) .
Pa is able to survive and proliferate in water with minimal nutrient
like respirator, contact lenses
.(eye infectionوممكن يسبب السائل الي بنحفظ فيه العدسات اللصقة)
Bacteriology
Bacteria.
Gram negative and gram positive.
Gram negative: Cocci, rods, acid-fast.
Gram negative rod: facultative, anaerobes, aerobics.
Pa is obligate aerobic gram negative rod (oxidation).
- It drives its energy from sugars by oxidation (unlike other
enterobacter).
Pa in non-fermenter (has a lot of cytochrome oxidase C).
Pa classification: non fermenting, oxidase positive, gram
negative rods.
Pa has a polar flagella and pilli that make Pa mobile.
positive oxidase test
SCIENTIFIC TEAM 4 –الفريق العلمي
Production of colorful water-soluble pigments:
Pyocyanin Pyoverdin (fluorescence)
Fluorescence: this characteristic can be used in early detection of
skin infection in burn patient (blue, yellow, green or red pigments)
بلون pigmentationبنلقي burn infection in the skinل يعني لما نتطلع على ا -
Paأزرق أو أصفر وهذا بيدلني على احتمالية وجود ال
Pyocyanin (blue) + Pyoverdin (yellow) = bright green color of
fluorescence
Also we can identify it from other gram negative bacteria
(Characteristic metallic sheen).
Intense fruity odor like the smell of crapes
SCIENTIFIC TEAM 5 –الفريق العلمي
Pa lives in slime enclosed biofilm.
The biofilm protects Pa from antibiotics and phagocytes, this biofilm
allows Pa to survive in this biofilom and replicate in this biofilm and
cause chronic infection CF patients.
Pa lives inside respiratory system, especially in CF patients as slime
enclosed biofilm.
بتكون على شكلcommunity وبتحميها طبقة من ال مغلفة مع بعضها البعضslime or
mucous وبالتالي هذه التجمعات أو ال ،biofilm بيحميها من الantibiotics.
General characteristics:
1. Obligate aerobic, gram negative bacilli non-sporing,
non-capsulate
2. Non-lactose fermenter
3. Oxidase positive
4. Glucose oxidizer
5. Catalase positive
6. Citrate positive
7. Motile by a polar flagella
8. It produces pigments
a) pyocyanin = blue green pigment (only in PA)
b) pyoveridin = yellow-fluorescence (PA & other bacteria)
c) pyorubin= red
SCIENTIFIC TEAM 6 –الفريق العلمي
Pathogenesis:
Opportunistic pathogen because it has a weak invasive ability.
In healthy individual it doesn’t cause a severe infection.
It takes any reduce of immune system opportunity.
Requires break of first-line defenses (wound or contaminated
solution).
Burn patient: the skin defense is lost so Pa will take this
opportunity and cause infection in burn area.
CF patient is immunocompromized, this patient has an
impairment in the respiratory tract (thick mucous), Pa will take
this opportunity and cause infection, and it will produce a
biofilm and cause chronic infection.
Virulent factors:
Endotoxin, exotoxin, enzymes, flagella, billi, biofilm, biocyanin,
type 3 section system
Endotoxin (lipid A): sepsis and endotoxin shock
SCIENTIFIC TEAM 7 –الفريق العلمي
Exotoxin A
Causes tissue necrosis
Consists of 2 portions; A-B toxin, and
produced by Pa.
Portion B binds to a receptor on the
cell membrane, A & B units become
internalized into the cell by
endocytosis and surrounded by a
vesicle.
A & B portions are separated
because of the acidity, portion B exits the cell by exocytosis,
while portion A enters cytoplasm and stops translation (stops
protein synthesis)
Stopping translation:
mRNA passes through the ribosome
The addition of amino acids to the polypeptide chain is called
elongation.
Elongation is facilitated by a factor called elongating factor, one
of them is called elongating factor 2 (EF2).
Exotoxin A inactivates the EF2,
Once the elongation stops, protein synthesis stops cell dies.
This means that there is a necrosis.
Similar in structure to Diptheriatoxin
Causes Dermatonecrosisin burn wounds, corneal damage in ocular
infections, and tissue damage and nexcrosisin chronic pulmonary
infections
SCIENTIFIC TEAM 8 –الفريق العلمي
Portion B (binding portion): binds to the receptor
Portion A (active portion): activates the EF2 and stops protein
synthesis.
Exo S, T, Y and U
Cause epithelial cell damage, facilitating bacterial spread, tissue
invasion, and necrosis.
Enzymes
Elastase, phospholipase C and protease are produced by Pa.
Histotoxic
Cause destruction and disruption of the body tissue
Facilitate the organism to reach blood stream
Eleastase:
Destruction of elastin-containing tissues (blood vessels,
lung tissue, skin), collagen, immunoglobulins (IgA and
IgG), and complement factors
Can produce hemorrhagic lesions (ecthymagangrenosum)
associated with disseminated infection
Elastase facilitates the organism to reach blood stream
and when get to the blood stream cause bacteremia and
sepsis.
Phospholipase C
Breaks down lipids and lecithin causing tissue destruction
SCIENTIFIC TEAM 9 –الفريق العلمي
T3SS (Type 3 secretion system)
Some strains of pa have this system.
Strains that have T3SS more violent than other strains that
don’t have this system.
They transfer exotoxin from bacteria directly into the adjacent
human cell.
This allows to exotoxin to avoid the antibodies.
SCIENTIFIC TEAM 10 –الفريق العلمي
Flagella and Pilli
Makes the Pa mobile
Pulmonary infection
Pilli facilitate the adhesion of pa to epithelial cell
Pyocunin can damage cilia and mucosal cells and immune cell in
respiratory tract
1. Can mediate tissue damage
2. It also stimulates IL-8 release, leading to enhanced attraction
of neutrophils
Considered a virulent factor.
Mediates tissue damage through production of oxygen radicals.
Alginate–mucoid exopolysaccharide that forms a shiny biofilm
protecting from antibodies, complement, phagocytosis, and
antibiotics.
Also considered a virulent factor.
SCIENTIFIC TEAM 11 –الفريق العلمي
Gram stain and culture
Gram stain can't differentiate Pa from other gram negative
rods.
Specimen obtained as indicated of type of infection
Gram stain: gram negative, rod that is motile and encapsulated
Electron microscope: polar flagella it has pili
Gram negative Motile encapsulated rod with polar flagella
Ps. aeruginosa is indistinguishable from other gram negative
bacilli. Therefore there is a little significance for gram staining.
Culture: far the most important and specific test for diagnose pa
infection
Grow well on ordinary media such as Blood Agar, Nutrient
Agar and MacConkey Agar.
Pa does not ferment lactose
Pa grows in non lactose fermenting colony in macConkey
agar (very characteristic for Pa).
SCIENTIFIC TEAM 12 –الفريق العلمي
Blood agar: -Metallic sheen -Many are haemolytic
MacConkey agar: -Colourless,non lactose fermenters Pa colorless Ecoli pink
Cetrimide agar: -selective media
بنلحظ هون الpositive oxidase testبناخد ال ،oxidase reagent وبنضعه على ،
.oxidase positive، وهذا معناه انه purple، بتصير colonyال
Biochemical reactions
Oxidative/fermentation glucose test-oxidative
Catalase-positive
Oxidase-positive
Nitrate reduction-positive
Citrate test-positive
SCIENTIFIC TEAM 13 –الفريق العلمي
Sugar fermentation tests
Glucose-only acid
Lactose-negative
Sucrose-negative
Mannitol-negative
These tests differentiate Pa from other oxidase negative gram
negative rods.
Pa non lactose fermenting oxidase positive gram negative rod.
Ps produce diffusible greenish
pigment which is a combination of
pyoveridin and pyocyanin.
Mucoid appearance of pa due to over production of alginate,
Alginate is an exopolysaccharide that provide the matrix for pa to
live in this biofilm
SCIENTIFIC TEAM 14 –الفريق العلمي
Summery the culture feature of Pa
Non lactose ferment oxidase positive
Green, blue
Metallic sheen
Mucoid appearance
Fruit smell
These feature are sufficient to diagnosis pa and confirmation by
biochemical test
Clinical Presentation
Pulmonary infections, common in cystic fibrosis patients
Primary skin infections: Opportunistic infections of existing
wounds (e.g., burns) to localized infections of hair follicles
UTI infections: Opportunistic infections in patients with indwelling
urinary catheters
Ear infections: range from mild irritation of external ear
"swimmer's ear“ to invasive destruction of cranial bones
Eye infections: Opportunistic infections of exposed, mildly
damaged corneas e.g., contact lens wearer
Bacteremia: Dissemination of bacteria from primary infection to
other organs and tissues
SCIENTIFIC TEAM 15 –الفريق العلمي
Ecthyma gangrenosum is a well recognized cutaneous
manifestation of severe, invasive infection by Pseudomonas
aeruginosathat is usually seen in immunocompromised, burn
patients, and other critically ill patients
Black necrotic ulcer,
often no pus
Burn
Bluish greenish discoloration
Tissue necrosis
Grape like smell
Tt: debridement and anti-
psudomnase
SCIENTIFIC TEAM 16 –الفريق العلمي
Malignant Otitis Externa
Diabetic and HIV pts
No fever
No leukocytosis.
Otologiand headache
tt: oral cipro
In 24-48 hrs
SCIENTIFIC TEAM 17 –الفريق العلمي
Healthy individuals may be infected by Pa and cause mild infection.
Most common to cause folliculitis (hair follical) that happens happy
when path water is contaminated with Pa.
Prevention
Observe proper hand hygiene (specially hands with finger ring).
Proper education of hospital related personnel on hand hygiene
Good housekeeping limit the chance of transmission of pa
Do not bring fruit ad row vegetable in burn unit
Use sterile water for washing medical equipment and devices
and do not use tape water
Limit use of broad spectrum ab disturb normal Flore, give pa an
opportunity infect
Place all CF patent in private room that should not share
bathroom or shower
Avoid direct contact
SCIENTIFIC TEAM 18 –الفريق العلمي
Treatment
Inherently resistant to many antibiotics (penicillin, ampicillin,
tetracycline, earlier aminoglycosides and sulfonamides).
Can mutate to more resistant strains during therapy.
Production of B-lactamases.
Combination of active antibiotics generally required for successful
therapy (Anti-β-lactam and aminoglycoside).
There are some strains of Pa that are even resistant to anti-pa
antibiotics.
Anti-Pa antibiotics:
Extended spectrum penicillin (ticarcillin piperacillin)
- not used alone used, usually combined with aminoglycoside.
Cabapenem (imipenem)
- very broad spectrum is because it is stable and the molecular
structure for it is very small so it can cross the cell wall of Pa (very
effective in treating Pa).
Aminoglycoside gentmtimicin amikacin tobramycin
Cephalosporin3rd 4th the 3rd: ceftazidime, 4th cefipime
fluoroquinolone (ciprofloxacin) good choice as a oral anti-Pa.
Monobactam
Polymyxin B
inhaled topramcine (for respiratory infection).
Vaccine experimental (ما في لقاح لحد الآن)
..بالتوفيق