Anaerobic streptococci and Bacteroides often occur in the mixed bacterial flora found in the sputum of patients with aspiration pneumonia or lung abscess and may be responsible for the spreading necrosis and foul pus encountered in these conditions. These organisms also occasionally produce acute otitis media, sinusitis, or mastoiditis. Anaerobic streptococci and Bacteroides occur frequently in chronic. suppuration of the ears, sinuses, or lungs; brain abscess may result from extension of infection from these sites. Anaerobic streptococci and Bacteroides are apparently the most common bacterial species isolated from brain abscesses.
Anaerobic streptococci also cause an infection of muscle that simulates clostridial myositis (“gas gangrene”)., Infection begins insidiously two to nine days after an injury and is characterized by fever and severe pain, swelling; and erythema extending from the wound. Disorientation occurs in some cases. Gas formation is invariably present but is rarely pronounced. Smears of the profuse seropurulent exudate usually reveal enormous numbers of gram-positive cocci among masses of pus cells, and cultures show anaerobic streptococci mixed with Streptococcus pyogenes or Staphylococcus aureus: Anaerobic streptococci in association with Staphylococcus aureus, Streptococcus pyogenes, or Proteus species may also cause a rather rare cutaneous infection known as “progressive bacterial synergistic gangrene.”
The infection usually begins after an operation on the thoracic or abdominal viscera. Erythema, edema, and finally gangrene and ulceration of the skin appear at the site of incision and extend peripherally. If the infection is not controlled, enormous ulcers may form. Fusospirochetal Infections. In gingivitis caused by F. fusiform and spirochetes, the free edges of the gums are reddened and swollen and bleed easily. Severe infections are characterized by painful, tender, extremely swollen and ulcerated gums, foul breath, and, rarely, fever and leukocytosis. Manifestations of fusospirochetal pharyngitis (Vincent’s angina) are a sore throat and pharyngeal ulcers covered with a gray necrotic pseudo-membrane, removal of which may cause bleeding. Fever and leukocytosis are observed occasionally.
Infection may occasionally spread from gums or pharynx to the buccal mucosa and underlying tissues to produce an extensive necrotizing lesion of the cheek or lip (cancrum oris, noma). Fusiform bacilli and indigenOus spirochetes also produce vulvovaginitis and balanitis, and may on occasion contribute to the genesis of aspiration pneumonia, lung abscess, and necrotizing cellulitis complicating human bites. Diagnosis. The presence .of localized infection with foul pus or signs of systemic infection after manipulation of the gastrointestinal or female pelvic organs should suggest the possibility of infection with an anaerobic organism, but the definitive diagnosis of Bacteroides or anaerobic streptococcus infection depends on isolation of the causative organism.
Hectic fever and intense rigors occurring several days after onset of severe sore throat or peritonsillar abscess, especially if associated with a firm tender cord indicating a thrombus in the internal jugular vein, should suggest the possibility of Bacteroides septicemia originating in the oropharynx. Exudates or blood must be cultured under anaerobic conditions. The frequent association of aerobes with anaerobes in exudates may make recognition and isolation of the anaerobic organisms difficult. Bacteroides in the blood may grow slowly, and blood cultures should be incubated for two to three weeks. Diagnosis of fusospirochetal infections is based on the appearance of the lesions and smears of exudates showing a predominance of fusiform bacilli and spirochetes. Interpretation of smears is difficult because fusospirochetes are often present in scrapings of the gingivodental fold from normal persons. Treatment.