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

• 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

• leukocytes• men: single unprotected exposure- 20-35%• women: 60-90%• Men:urethra

sterilityvas 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

• 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

• 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) respiratory2) 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

• 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 cases600,000 deaths/year

• cephalosporins

1909 newspaper illustration