Microbiology of secondarily infected diaper dermatitis

Specimens obtained from 67 infants with secondarily infected diaper dermatitis were cultured for aerobic and anaerobic bacteria. Bacteria growth was obtained in 58. Aerobic facultative bacteria or Candida sp. only were present in 28 patients (48%), anaerobic bacteria only in 11 (19%), and mixed anaerobic with aerobic, facultative, or yeast flora was present in 19 (33%). Ninety-one bacterial or fungal isolates were recovered (1.6 per specimen), 54 (0.9 per specimen) aerobic or facultative bacteria, 8 (0.1 per specimen) Candida sp., and 31 (0.6 per specimen) strict anaerobes. The predominant aerobic and facultative bacteria were Staphylococcus aureus (23 isolates), Streptococcus sp. (16), and Escherichia coli (6). The predominant anaerobes included Bacteroides sp. (12, including 9 Bacteroides fragilis group) and Peptostreptococcus sp. (11). Single bacterial isolates were recovered in 32 (55%) patients, 18 of which were S. aureus. Twenty-five beta-lactamase-producing bacteria were detected in 22 (51%) of the 43 tested patients. These included 16 S. aureus and 6 B. fragilis group. These data highlight the importance of anaerobic bacteria in the polymicrobial nature of secondarily infected diaper dermatitis.