Bacillus and Clostridium Classification

Positive Bacilli

• Divided into spore forming and non-spore forming

Spore Forming Positive Bacilli

• Divided into aerobic and anaerobic types

Aerobic Spore Forming Positive Bacilli

• Has 2 types: Bacillus anthracis and Bacillus cereus
• Bacillus anthracis causes cutaneous anthrax, pulmonary anthrax, and intestinal anthrax
• Bacillus cereus causes enterotoxin food poisoning

Anaerobic Spore Forming Positive Bacilli

• Has 4 types: Clostridium tetani, Clostridium botulinum, Clostridium perfringens, and Clostridium difficile
• Clostridium tetani causes spastic muscle paralysis
• Clostridium botulinum causes flaccid muscle paralysis
• Clostridium perfringens causes gas gangrene myonecrosis
• Clostridium difficile causes diarrhea and colitis due to long-term antibiotic therapy

Non-Spore Forming Positive Bacilli

• Has 2 examples: Corynebacterium and Lactobacillus
• Corynebacterium causes diphtheria

Negative Bacilli

• Divided into 4 types: rod, curved, cocci, and mycobacterium

Rod Negative Bacilli

• Divided into 2 types: lactose fermented and non-lactose fermented

Lactose Fermented Negative Bacilli

• Motile lactose fermenter example: E. coli
• E. coli causes UTI and neonatal meningitis
• Non-motile lactose fermenter examples: Klebsiella
• Klebsiella causes UTI and pneumonia

Non-Lactose Fermented Negative Bacilli

• Motile non-lactose fermenter examples: Proteus and Salmonella
• Proteus causes urease +, bacteremia, and UTI
• Salmonella causes H2S +, septicemic, enteric fever, and food poisoning
• Non-motile non-lactose fermenter example: Shigella
• Shigella causes H2S -, bacillary dysentery

Curved Negative Bacilli

• Has 3 examples: Helicobacter pylori, Vibrio cholera, and Campylobacter
• Vibrio cholera causes comma-shaped, alkaliphilic, and causes cholera
• Helicobacter pylori causes acidophilus, microphilic, and peptic ulcer

Cocci Negative Bacilli

• Has 3 examples: Brucella, Haemophilus influenza, and Pseudomonas aeruginosa
• Brucella causes Malta fever, it's capnophilic
• Haemophilus influenza causes meningitis and pneumonia in infants, it's on chocolate agar
• Pseudomonas aeruginosa causes pleomorphic, and in patients with severe burns and immunosuppressed

Mycobacterium

• A type of non-spore forming rod
• Causes Mycobacterium tuberculosis and Mycobacterium leprosy