Microbiology, Epidemiology: -

Pathogenesis:- Nonsporulating anaerobic bacteria are important components of the normal flora of mucosal surfaces of the mouth, lower GI tract, skin, and female genital tract and contribute to physiologic, metabolic, and immunologic functions of the host.

  • Most clinically relevant anaerobes are relatively aerotolerant and can

survive for as long as 72 h in the presence of low levels of oxygen.

– Clinically relevant anaerobes include gram-positive cocci (e.g., Peptostreptococcus species), gram-positive rods (e.g., spore-forming clostridia and Propionibacterium acnes), and gram-negative bacilli (e.g., the B. fragilis group in the normal bowel flora, Fusobacterium species in the oral cavity and GI tract, Prevotella species in the oral cavity and female genital tract, and Porphyromonas species in the oral flora).

  • Infections caused by anaerobes are typically polymicrobial (including at least one anaerobic organism and sometimes involving microaerophilic and facultative bacteria) and occur when organisms penetrate a previously sterile site that has a reduced oxidation-reduction potential—e.g., from tissue ischemia, trauma, surgery, perforated viscus, shock, or aspiration. Bacterial synergy, bacterial virulence factors, and mechanisms of formation are factors involved in the pathogenesis of anaerobic infections.


The clinical presentation of anaerobic infections depends, in part, on the anatomic location affected.

  • Mouth, head, and neck infections: Odontogenic infections (e.g., dental caries, periodontal disease, gingivitis) are common, can spread locally,and may be life-threatening.

– Acute necrotizing ulcerative gingivitis (trench mouth, Vincent’s stomatitis) is associated with bleeding tender gums, foul breath, and ulceration with gray exudates, often affecting malnourished children, pts with leukemia, or pts with a debilitating illness. Widespread destruction of bone and soft tissue can develop. Lesions heal but leave disfiguring defects.

– Acute necrotizing infection of the pharynx is associated with ulcerative gingivitis. Pts have a sore throat, foul breath, fever, a choking sensation, and tonsillar pillars that are swollen, red, ulcerated, and covered with a gray membrane. Aspiration of infected material can lead to a lung abscess.

– Peripharyngeal infections include peritonsillar abscess (quinsy; caused by a mixed flora including anaerobes and group A streptococci) and submandibular space infection (Ludwig’s angina), which arises from the second and third molars in 80% of cases and is associated with swelling (which can lead to respiratory obstruction), pain, trismus, and displacement of the tongue.

– Chronic sinusitis and otitis are commonly due to anaerobes.


The medicines that can be thought of use are: -

  • Camphor
  • Veratrum album
  • Cuprum met
  • Sulphur
  • Calendula
  • Lachesis.