Transcript Bacterial Diseases

Bacterial Diseases
Pathogenicity
• “the state of producing or being able to
produce pathological changes and disease”
Staphylococcus
• “a genus of gram-negative, nonmotile,
opportunistic bacteria which tend to
aggregate in irregular, grape-like clusters”
Readings Question #1
• Staphylococcus aureus is the most pathogenic
of the staphylococci. What are its toxins
capable of doing? What enzymes does it
produce, and what is their known effect?
Staphylococcal Food Poisoning
• caused by ingesting an enterotoxin
• high resistance to heat, drying and radiation,
and high osmotic pressures
• inhabitant of nasal passages…contaminates
the hands…..readily enters food
• mechanical vectors
• mayonnaise, cream sauces
Skin and Wound Infections
• Sty: “infected follicle of an eyelash”
Skin and Wound Infections (cont’d)
• Pimple: infected hair follicle
• Abscess: more serious hair follicle infection
– furuncle/boil: superficial
– carbuncle: deeper
• Risk of underlying tissues becoming infected
• Toxemia: toxins circulate
Scalded Skin Syndrome
Toxic Shock Syndrome
• S. aureus growth associated with the use of a
new type of highly absorbent vaginal tampon
• swell with menstrual fluids and adhere to the
vagina
• tears in the vaginal wall
Streptococcus
“spherical shaped bacteria occurring in chains”
What are the implications for the embalmer
when dealing with saprophytes?
Streptococcus pneumoniae
( pneumococcus)
• gram-positive ovoid bacterium
• cell pairs surrounded by capsule
• common cause of:
1) lobar pneumonia
2) meningitis
3) otitis media
Lobar Pneumonia
• Readings question #2:
• What is lobar pneumonia, and how is it
characterized?
• What are some of the predisposing conditions
for this disease?
• penicillin and fluoroquinolones
Meningitis
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70% of the population are healthy carriers
Gram-positive encapsulated diplococcus
Leading cause of bacterial meningitis
Most cases between 1 month and 4 years
Broad-spectrum cephalosporins
CSF obtained by a spinal tap
Vaccine: Pneumococcal Conjugated Vaccine
Otitis Media
• 85% before 3 years of age (Eustachian Tubes)
Streptococcus pyogenes
• Scarlet Fever: streptococcal pharyngitis
• Septic Sore Throat: respiratory secretions
– penicillin
• Puerperal Sepsis: Childbirth/Childbed Fever
• Rheumatic Fever: arthritis and fever
– 50% inflammation of the heart
– penicillin
– Syndenham’s chorea
Neisseria
gram-negative cocci that inhabit the
mucous membranes
Readings Question #3
• One of the most common communicable
diseases in the United States is gonorrhea, an
STD caused by Neisseria gonorrhoeae. How
does it attach to the tissues? How does it
spread? What is its only natural host? What
is its most common symptoms? When do
symptoms appear?
Gonorrhea
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leukocytes
men: single unprotected exposure- 20-35%
women: 60-90%
Men:
urethra
sterility
vas deferens
Women
• insidious
• cervix
• abdominal pain: PID
Men and Women
• Untreated gonorrhea can disseminate and
become a serious, systemic infection.
Opthalmia Neonatorum
• antibiotics/silver nitrate
Antibiotic Resistance
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penicillin
fluorquinolone antibiotics
frequent coinfection with chlamydia
include antichlamydial in treatment
– tetracycline
• Diagnosis: ELISA- detects N. gonorrhoeae
Readings Question 4
• Gonorrhea is a common cause of pelvic
inflammatory disease in women. What are its
signs and symptoms? What is epididymitis?
PID
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1 in 10 women
1 in 4: serious complications
coinfection with chlamydial bacteria
barrier contraceptives with spermicides
salpingitis: most serious form
– ectopic/tubal pregnancy
• Treatment: gonococcus and chlamydia
Neisseria meningitides
(meningococcus)
• aerobic, gram-negative bacteria with a
capsule, pili, and production of endotoxins
• endotoxins are primarily responsible for
symptoms
• most distinguishing feature is the rash that
does not fade when pressed
Meningococcus Rash
• Spots do not blanch when pressed with the
glass.
Meningococcus Rash
Septicemic Rash
Meningococcal Meningitis
• typically begins with a throat infection which
leads to bacteremia, and eventually meningitis
• generally occurs in children under 2 years
• residual damage
• sporadic outbreaks
• vaccine
• penicillin and cephalosporin
Menningococcemia
Gangrene of the hand of a 4 month old.
Clostridium
• obligate anaerobes
• rod-shaped cells that contain endospores
• Clostridium botulinum: botulin
Readings Question 5
• Clostridium tetani causes what bacterial
infection? Describe the characteristics of this
microbe. Where is it found? What are its
symptoms, and what causes them?
Gas Gangrene
Gas Gangrene
Readings Question #6
Clostridium perfringens is the causative agent of
a postmortem condition known as tissue gas.
List 3 things that may result in this condition in
the decedent.
List 7 conditions that predispose the decedent
to tissue gas formation.
Food Intoxication
• Clostridium perfringens Gastroenteritis: one
of the more common forms of food poisoning
in the United States
• improper handling of meat during the
slaughtering of animals
• 2 main causes: 1) keeping foods warm for
more than 20 minutes
2) inadequate refrigeration
Corneybacterium
• Diptheria: caused by Corneybacterium
diptheria
• 2 forms:
1) respiratory
2) cutaneous
Respiratory Diptheria
• Begins with a sore throat, followed by general
malaise and swelling of the neck.
• DTaP vaccine
• antibiotics used in
conjunction with
antitoxin
Cutaneous Diptheria
• C. diptheria infects the skin
• minimal systemic circulation of the toxin
• slow-healing ulcerations covered by a gray
membrane
Reading Question #7
Tularemia/Rabbit Fever is a zoonotic disease
caused by the bacterium Francisella
tularensis. What are the characteristics of this
parasite? How can it enter the body? What
are the signs associated with this disease?
Proliferation can lead to sepsis.
Streptomycin is the antibiotic of choice.
Salmonella typhi
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most virulent strain and causes typhoid fever
pathogen not found in animals
spread only in the feces of other humans
S. typhi multiply within phagocytic cells,
disseminated into multiple organs
• phagocytic cells “lyse”
• high fever and headache are 1st symptoms
• diarrhea in 2nd or 3rd week
Typhoid Fever
• 350 – 500 annual cases in the United States
• 70% foreign travel
• worldwide:
16 million annual cases
600,000 deaths/year
• cephalosporins
1909 newspaper illustration