Introduction: The frequency of bacterial dermohypodermal infections would appear to be increasing in western countries, particularly severe necrotizing forms.
Patients and methods: We attempted to determine: (1) the incidence of the two most well-defined forms of bacterial dermohypodermal infections (erysipelas and necrotizing fasciitis) in a retrospective study of hospitalized cases seen over a period of 13 years in the Limoges University Hospital and (2) the role of streptococci as causative agents in bacterial dermohypodermal infections in the adult by collecting bacteriological data in 174 cases of erysipelas and 31 cases of necrotizing fasciitis.
Results: This retrospective analysis confirmed that the annual incidence of erysipelas was constantly increasing over the study period (1978-1991) while the annual incidence of necrotizing fasciitis was much lower and more constant. The two incidence curves were not parallel. Bacteriology, detection of streptococci (groups A, B, C or G) in skin specimen was better with direct immunofluorescence (64 p. 100) than with latex agglutination (47 p. 100) or classic culture techniques (28 p. 100) for erysipelas. Streptococci were determined to be the causative agent in 79 p. 100 (137/174) of the cases of erysipelas using at least one of the 3 bacteriological tests and/or serology. Group A streptococci predominated (67 p. 100 of the cases). For necrotizing fasciitis, streptococci was identified with classical culture technique, latex agglutination and/or serology in 12/131 cases (39 p. 100), again with a group A predominance (7 cases). In the other cases, multiple microbial flora (12 cases) were found including Staphylococcus aureus (3 cases) and Serratia liquefaciens (1 case).
Conclusion: These results show that streptococci (group A predominantly and group G to a lesser extent) were the major, though not exclusive, causative agents in bacterial dermohypodermal infections in the adult, including necrotizing forms.