Bactéries anaérobies strictes: Taxonomie et bilan de sensibilité aux antimicrobiens

[Anaerobic deep abscesses with unusual location: report of 5 cases]

OBJECTIVE

Anaerobic deep abscesses are rare and may have unusual location leading to severe outcome due to delayed diagnosis and treatment. In order to improve their diagnosis, we report and analyse 5 new cases.

METHODS

Patients were seen from 1999 to 2003 in a single department of internal medicine of the university hospital of Marseille.

RESULTS

Five new cases were diagnosed consisting in 3 females and 2 males with a medium age of 56,8 years, with unusual location in 4 cases: epidural (2), psoas (1) and sub-diaphragmatic (1) or circumstances in one case of pulmonary abscess unrelated to inhalation. Predisposing conditions thought to compromise resistance to infection were found in all cases: social poverty (4/5), alcoholism (3/5), smoking (4/5), teeth and periodontal disease (4/5), neoplasia (2/5), iatrogenic disease (2/5). Symptoms were insidious (5/5) and unspecific but were always related to the abscess location. Abscesses were frequently found distant from the initial focus of infection because of frequent hematogenous spread (4/5). Drainage of the collection led to bacterial identification in all cases (4/4), although blood cultures could be positive (3/5) and helpful in one case in which drainage was not possible (1/5). The isolated organisms always corresponded to the suspected initial focus (oropharynx 4/5 and digestive 1/5). Finally, combination of surgical drainage and double prolonged antibiotherapy (penicillin+metronidazole) was the elected treatment.

CONCLUSION

Since hematogenous diffusion is frequent, anaerobic infection should be suspected in any case of deep abscess affecting patients with predisposing conditions such as poverty, severe teeth disease or iatrogenic procedure.

E-test antibiotics susceptibility of strict anaerobic bacteria

The E-test is convenient for testing susceptibility of anaerobes. From September 1998 to September 1999, 194 strains (105 Gram-positive bacteria, 89 Gram-negative bacteria) of clinically relevant samples were tested against five antibiotics benzylpenicillin, amoxicillin-clavulanic acid, clindamycin, metronidazole and imipenem on blood agar plates. Resistance to benzyl penicillin is widespread and Gram-negative bacteria and resistance to amoxicillin-clavulanic acid is exceptional. Metronidazole is very effective against anaerobes except non-spore-forming aerotolerant Gram-positive rods and Peptostreptococcus micros.