“Not so typical Bacteria”
Mycoplasma
Mycobacterium
Rickettsia
Chlamydia
Borrelia
Exotoxin vs Endotoxin
Exotoxin
Endotoxin
Gram + & -
Protein (can be denatured by heat)
Non fever producing
Ex) S. aureus, Bacillus anthracis
Gram –
Lipopolysaccharide (LPS)
Lipid
Cause fever
Component of Gram – membrane
Toxic portion released when cell lysed
Ex) E.coli, Salmonella typhi, Shigella, Vibrio cholera
4 species of Clostridium:
Clostridium difficile- diarrhea, Pseudomembranous colitis
Clostridium botulinum- botulism
Clostridium tetani- neonatal tetanus
Clostridium perfringens- cellulitis, gas gangrene
Skin:
1. Crowded conditions (competition with NF)
2. Dry
3. High salt
4. Sloughing off of dead cells
5. Low pH
3 main types:
Intoxications in preformed food
Intoxications due to toxins manufactured in the body
Intestinal invasive diseases
Clostridium botulinum
Clostridium perfringens
Salmonella typhi
Bacillus cereus
Vibrio cholera
Listeria monocytogenes
Staphylococcus aureus
Shigella dysenteriae
Listeria monocytogenes
E. coli O157:H7
Campylobacter jejuni
Yersinia enterocolitica
Roles of Normal Flora:
1. Common sources of infection
2. Immune stimulation
3. Keeping out Invaders: Commensal bacteria. Some produce antibiotics of bacteriocins.
4. Nutrition and metabolism: E. coli and Bacteroides synthesize vitamins K and B12
5. Possible source of carcinogens
Case Study Streptococcus pneumoniae The day after Mr. B. was admitted to the hospital, the local public health department was noticed that eight customers at the restaurant where he worked had developed severe vomiting and diarrhea 4 to 6 hours after eating there. Health department investigators learned that 6 of the 8 persons who had diarrhea had eaten cream pie. Cultures of the remaining cream pies in the restaurant refrigerator were positive for S. aureus. A preformed staphylococcal toxin called enterotoxin A was detected in the cream pies. The organisms from the contaminated food belonged to the same pulsed field gel electrophoresis type as those isolated from the patient’s abscess and blood and were therefore likely to be the same.
In January, Mr. P., a 68-year-old grandfather and a heavy smoker, noted that he had nasal congestion, muscle aches, and a low-grade fever. He felt that his symptoms were resolving until he abruptly developed a shaking chill, cough, and severe pain on the right side of his chest that worsened with breathing. The cough was productive of rust- colored sputum. When he was seen in the emergency department 2 days later, he appeared to acutely ill and a temperature of 40°C. His respiratory rate was rapid at 30 breaths per minute.
• The laboratory reported that Mr. P.’s white blood cell count was 23,000/μl 3 , indicative of leukocytosis; often characterizes bacterial infection
• A chest radiograph revealed a dense infiltrate in the right lung.
• A Gram stain of the sputum showed many neutrophils and Gram positive diplococci
• Streptococcus pneumoniae
• Community acquired pneumonia
Bacteroides fragilis & Escherichia coli
Ms. A., an 18-year-old
