3. IMPORTANT PATHOGENS
3 important pathogens in this group
1. CORYNEBACTERIUM DIPHTHERIAE
2. LISTERIA MONOCYTOGENES
3. GARDNERELLA VAGINALIS
4. CORYNEBACTERIUM
DIPHTHERIA
Gram positive rods
Appear club shaped
Arranged in palisades or in V or L
shaped
Rods are in form of beads
Beads consist of granules of
highly polymerized polyphosphate
5. DISEASE
Diphtheria
Other corynebacter are implicated in opportunistic
infections
TRANSMISSION
Humans are the only natural resource
Resides in the upper respiratory tract and transmitted by
air born droplet
Can also infect skin at pre existing lesion
6. PATHOGENESIS
Organism is first establish and maintain itself in throat
Diphtheria toxin inhibits protein synthesis by ADP- ribosylation of
elongation factor (EF-2)
Toxin effects all eukaryotic cells but has an effect on prokaryotic cells
2 functional domains of toxin
binding domain binding of toxin on cell memb.
Active domain enzymatic activity that cleaves down
nicotinamide from NAD
DNA code for Diphtheria toxin part of DNA temperate phage
Beta phage
7.
8. CLINICAL FINDINGS
Most prominent sign thick gray adherent pseudo membrane
over the tonsils and throat
3 prominent complications are
1. Extension of the membrane into larynx and trachea air way
obstruction
2. Myocarditis accompanied by arrhythmias and circulatory collapse
3. Nerve weakness and paralysis esp. of cranial nerves
Peripheral neuritis affecting muscles of extremities also occur
Cutaneous diphtheria causes ulcerating skin lesions covered by grey
membrane
9.
10. LABORATORY DIAGNOSIS
Involves both isolating organism and demonstrating toxin production
A throat swab should be cultured on Loffler’s medium , a tellurite
plate and a blood agar
If diphtheria is reused from cultures ,either animal inoculation or an
antibody based gel diffusion precipitation test is prepared to
document toxin production
PCR assay can also be used
Smear of the throat swab should be stained with gram stain and
methylene blue tapered pleomorphic gram positive rods can be
suggestive
11.
12. TREATMENT
The treatment of choice is anti toxin which
should be given immediately on the basis of
clinical impression
Toxin binds rapidly and irreversible to cells .
Once bound can't be neutralized
Function of anti toxin is to neutralize
unbound toxin in blood
Treatment with penicillin G or erythromycin
is also recommended
13. PREVENTION
Children are immunized with diphtheria toxoid
Diphtheria toxoid is prepared by treating exotoxin with
formaldehyde , which inactivates the toxin toxicity but
antigenicity remains intact
Immunization consists of three doses given at 2 4 6
months age
14. LISTERIA MONOCYTOGENES
Arranged in V or L shaped
Exhibits unusual tumbling movement that distinguish it
from carynebacteria which are non motile
Colonies on blood agar plate produce a narrow zone of
Beta hemolysis
Listeria grow well at cold temperature , so
contaminated food in refrigerator can increase the risk
the of gastroenteritis
growth is called cold enhancement
DISEASES
Causes meningitis and sepsis in new born, pregnant
women , immunocompromised patient
15. PATHOGENESIS
Infection occur in 2 clinical condition
1. In fetus or in new born In placenta or during delivery
2. In pregnant women and immunocompromised patients
Organism is distributed in animals soil and plants transmitted to human
by ingesting pasteurized milk , under cooked meat , raw vegetables
Following ingestion bacteria enters colon and to female genital tract
Invasion of cells is mediated by internal in made by Listeria and
adhesion on the surface of human cells
Organism produce Listeriolysin allows it to escape from phagosome into
cytoplasm
Cell mediated immunity is more imp. Than humoral immunity
Move from one human cells to another by actin rockets filaments
17. CLINICAL FINDINGS
Infections during pregnancy cause abortions ,
premature delivery or sepsis during prepartom
period
New born infected at the time of delivery can have
acute meningitis 1 – 4 weeks later
Infection in immunocompromised adults can sepsis
of meningitis
Gastroenteritis is characterized by watery diarrhea
fever headache myalgia and abdominal cramps but
little vomiting
caused by contaminated diary products
and under cooked meat
18.
19. LABORATORY DIAGNOSIS
Made by gram stain and culture
Formation of smell gray colonies with a
narrow zone of Beta hemolytic on blood
agar plate suggests presence of listeria
Identification of the organism as L.
monocytogenes is made by sugar
fermentation test
20. TREATMENT
Consist of ampicillin with or without gentamycin
Trimethoprim , sulfonamide can also be used
Listeria gastroenteritis typically doesn’t require any
treatment
21. PREVENTION
Limiting the exposure to potential sources
such as farm animals unpasteurized milk
products and raw vegetables is
recommendable
Trimethoprim sulfamethoxazole to
prevent pneumocystis pneumonia can also
prevent listeriosis
22. GARDNERELLA VAGINALIS
Small facultative
Gram variable rods
Gram variable refers to some organism
that are some purple and others are
pink
Wall is thin and older organism tend to
loose the purple color
23. DISEASE
Cause bacterial vaginosis but no vaginitis
PATHOGENESIS
Gardenral vaginalis after found in association
with anaerobes and nonaerobes
Bacterial vaginosis is not transmitted by
sexual activity
It is considered to be a dysbiosis in which
lactobacillus that are found as normal flora
in the vagina is replaced by those organism
24. CLINICAL FINDINGS
Bacterial vaginosis is characterized by a
malodorous , white or gray colored vaginal
discharge
Discharge has characteristic fishy odor
Inflammatory changes are typically absent
which is why it is called vaginosis rather than
vaginitis
Mild itching may occur
25. LABORATORY DIAGNOSIS
Based on the clue cell ( vaginal epithelial cells covered
with bacteria ) in microscopic examination of vaginal
discharge
Whiff test treating vaginal discharge with 10% KOH
and smelling pungent , fishy odor is positive
A pH of greater than 4.5 of vaginal discharge
indicates bacterial vaginosis
TREATMENT AND
PREVENTION
Drug metronidazole
There is no vaccine
26.
27. Hello there!
My name is Syeda Maryam . I am here to assist you, whether you are a
student or teacher . I can make educational presentations/slides for
you based on the content you’ll give to me .
I have 2 years of experience in this field of making slides on power point
for students and teachers as well.
so if you need any help then contact me through my freelancer
account at Guru.com
https://www.guru.com/pro/dashboard.aspx
you can view my portfolio at Slideshare.net and facebook page
https://www.slideshare.net/syedamaryam10
https://www.facebook.com/Study-Slides-107976133868241
you can also contact me through my email
maryamhy95@gmail.com I’ll be glad to help you!
See you soon!